atmel_serial.c 77.2 KB
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/*
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 *  Driver for Atmel AT91 / AT32 Serial ports
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 *  Copyright (C) 2003 Rick Bronson
 *
 *  Based on drivers/char/serial_sa1100.c, by Deep Blue Solutions Ltd.
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
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 *  DMA support added by Chip Coldwell.
 *
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 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#include <linux/tty.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/serial.h>
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#include <linux/clk.h>
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#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/tty_flip.h>
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#include <linux/platform_device.h>
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#include <linux/of.h>
#include <linux/of_device.h>
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#include <linux/of_gpio.h>
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#include <linux/dma-mapping.h>
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#include <linux/dmaengine.h>
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#include <linux/atmel_pdc.h>
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#include <linux/atmel_serial.h>
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#include <linux/uaccess.h>
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#include <linux/platform_data/atmel.h>
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#include <linux/timer.h>
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#include <linux/gpio.h>
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#include <linux/gpio/consumer.h>
#include <linux/err.h>
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#include <linux/irq.h>
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#include <linux/suspend.h>
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#include <asm/io.h>
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#include <asm/ioctls.h>
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#define PDC_BUFFER_SIZE		512
/* Revisit: We should calculate this based on the actual port settings */
#define PDC_RX_TIMEOUT		(3 * 10)		/* 3 bytes */

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/* The minium number of data FIFOs should be able to contain */
#define ATMEL_MIN_FIFO_SIZE	8
/*
 * These two offsets are substracted from the RX FIFO size to define the RTS
 * high and low thresholds
 */
#define ATMEL_RTS_HIGH_OFFSET	16
#define ATMEL_RTS_LOW_OFFSET	20

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#if defined(CONFIG_SERIAL_ATMEL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
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#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

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#include "serial_mctrl_gpio.h"

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static void atmel_start_rx(struct uart_port *port);
static void atmel_stop_rx(struct uart_port *port);

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#ifdef CONFIG_SERIAL_ATMEL_TTYAT
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/* Use device name ttyAT, major 204 and minor 154-169.  This is necessary if we
 * should coexist with the 8250 driver, such as if we have an external 16C550
 * UART. */
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#define SERIAL_ATMEL_MAJOR	204
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#define MINOR_START		154
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#define ATMEL_DEVICENAME	"ttyAT"
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#else

/* Use device name ttyS, major 4, minor 64-68.  This is the usual serial port
 * name, but it is legally reserved for the 8250 driver. */
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#define SERIAL_ATMEL_MAJOR	TTY_MAJOR
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#define MINOR_START		64
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#define ATMEL_DEVICENAME	"ttyS"
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#endif

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#define ATMEL_ISR_PASS_LIMIT	256
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struct atmel_dma_buffer {
	unsigned char	*buf;
	dma_addr_t	dma_addr;
	unsigned int	dma_size;
	unsigned int	ofs;
};

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struct atmel_uart_char {
	u16		status;
	u16		ch;
};

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/*
 * Be careful, the real size of the ring buffer is
 * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer
 * can contain up to 1024 characters in PIO mode and up to 4096 characters in
 * DMA mode.
 */
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#define ATMEL_SERIAL_RINGSIZE 1024

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/*
 * at91: 6 USARTs and one DBGU port (SAM9260)
 * avr32: 4
 */
#define ATMEL_MAX_UART		7

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/*
 * We wrap our port structure around the generic uart_port.
 */
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struct atmel_uart_port {
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	struct uart_port	uart;		/* uart */
	struct clk		*clk;		/* uart clock */
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	int			may_wakeup;	/* cached value of device_may_wakeup for times we need to disable it */
	u32			backup_imr;	/* IMR saved during suspend */
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	int			break_active;	/* break being received */
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	bool			use_dma_rx;	/* enable DMA receiver */
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	bool			use_pdc_rx;	/* enable PDC receiver */
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	short			pdc_rx_idx;	/* current PDC RX buffer */
	struct atmel_dma_buffer	pdc_rx[2];	/* PDC receier */

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	bool			use_dma_tx;     /* enable DMA transmitter */
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	bool			use_pdc_tx;	/* enable PDC transmitter */
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	struct atmel_dma_buffer	pdc_tx;		/* PDC transmitter */

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	spinlock_t			lock_tx;	/* port lock */
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	spinlock_t			lock_rx;	/* port lock */
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	struct dma_chan			*chan_tx;
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	struct dma_chan			*chan_rx;
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	struct dma_async_tx_descriptor	*desc_tx;
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	struct dma_async_tx_descriptor	*desc_rx;
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	dma_cookie_t			cookie_tx;
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	dma_cookie_t			cookie_rx;
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	struct scatterlist		sg_tx;
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	struct scatterlist		sg_rx;
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	struct tasklet_struct	tasklet_rx;
	struct tasklet_struct	tasklet_tx;
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	atomic_t		tasklet_shutdown;
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	unsigned int		irq_status_prev;
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	unsigned int		tx_len;
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	struct circ_buf		rx_ring;
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	struct mctrl_gpios	*gpios;
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	unsigned int		tx_done_mask;
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	u32			fifo_size;
	u32			rts_high;
	u32			rts_low;
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	bool			ms_irq_enabled;
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	u32			rtor;	/* address of receiver timeout register if it exists */
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	bool			has_frac_baudrate;
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	bool			has_hw_timer;
	struct timer_list	uart_timer;
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	bool			suspended;
	unsigned int		pending;
	unsigned int		pending_status;
	spinlock_t		lock_suspended;

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	struct {
		u32		cr;
		u32		mr;
		u32		imr;
		u32		brgr;
		u32		rtor;
		u32		ttgr;
		u32		fmr;
		u32		fimr;
	} cache;

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	int (*prepare_rx)(struct uart_port *port);
	int (*prepare_tx)(struct uart_port *port);
	void (*schedule_rx)(struct uart_port *port);
	void (*schedule_tx)(struct uart_port *port);
	void (*release_rx)(struct uart_port *port);
	void (*release_tx)(struct uart_port *port);
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};

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static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
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static DECLARE_BITMAP(atmel_ports_in_use, ATMEL_MAX_UART);
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#ifdef SUPPORT_SYSRQ
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static struct console atmel_console;
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#endif

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#if defined(CONFIG_OF)
static const struct of_device_id atmel_serial_dt_ids[] = {
	{ .compatible = "atmel,at91rm9200-usart" },
	{ .compatible = "atmel,at91sam9260-usart" },
	{ /* sentinel */ }
};
#endif

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static inline struct atmel_uart_port *
to_atmel_uart_port(struct uart_port *uart)
{
	return container_of(uart, struct atmel_uart_port, uart);
}

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static inline u32 atmel_uart_readl(struct uart_port *port, u32 reg)
{
	return __raw_readl(port->membase + reg);
}

static inline void atmel_uart_writel(struct uart_port *port, u32 reg, u32 value)
{
	__raw_writel(value, port->membase + reg);
}

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#ifdef CONFIG_AVR32

/* AVR32 cannot handle 8 or 16bit I/O accesses but only 32bit I/O accesses */
static inline u8 atmel_uart_read_char(struct uart_port *port)
{
	return __raw_readl(port->membase + ATMEL_US_RHR);
}

static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
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{
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	__raw_writel(value, port->membase + ATMEL_US_THR);
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}

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#else

static inline u8 atmel_uart_read_char(struct uart_port *port)
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{
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	return __raw_readb(port->membase + ATMEL_US_RHR);
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}

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static inline void atmel_uart_write_char(struct uart_port *port, u8 value)
{
	__raw_writeb(value, port->membase + ATMEL_US_THR);
}

#endif

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#ifdef CONFIG_SERIAL_ATMEL_PDC
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static bool atmel_use_pdc_rx(struct uart_port *port)
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{
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
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	return atmel_port->use_pdc_rx;
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}

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static bool atmel_use_pdc_tx(struct uart_port *port)
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{
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
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	return atmel_port->use_pdc_tx;
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}
#else
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static bool atmel_use_pdc_rx(struct uart_port *port)
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{
	return false;
}

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static bool atmel_use_pdc_tx(struct uart_port *port)
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{
	return false;
}
#endif

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static bool atmel_use_dma_tx(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

	return atmel_port->use_dma_tx;
}

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static bool atmel_use_dma_rx(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

	return atmel_port->use_dma_rx;
}

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static bool atmel_use_fifo(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

	return atmel_port->fifo_size;
}

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static void atmel_tasklet_schedule(struct atmel_uart_port *atmel_port,
				   struct tasklet_struct *t)
{
	if (!atomic_read(&atmel_port->tasklet_shutdown))
		tasklet_schedule(t);
}

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static unsigned int atmel_get_lines_status(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	unsigned int status, ret = 0;

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	status = atmel_uart_readl(port, ATMEL_US_CSR);
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	mctrl_gpio_get(atmel_port->gpios, &ret);

	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
						UART_GPIO_CTS))) {
		if (ret & TIOCM_CTS)
			status &= ~ATMEL_US_CTS;
		else
			status |= ATMEL_US_CTS;
	}

	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
						UART_GPIO_DSR))) {
		if (ret & TIOCM_DSR)
			status &= ~ATMEL_US_DSR;
		else
			status |= ATMEL_US_DSR;
	}

	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
						UART_GPIO_RI))) {
		if (ret & TIOCM_RI)
			status &= ~ATMEL_US_RI;
		else
			status |= ATMEL_US_RI;
	}

	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
						UART_GPIO_DCD))) {
		if (ret & TIOCM_CD)
			status &= ~ATMEL_US_DCD;
		else
			status |= ATMEL_US_DCD;
	}

	return status;
}

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/* Enable or disable the rs485 support */
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static int atmel_config_rs485(struct uart_port *port,
			      struct serial_rs485 *rs485conf)
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{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	unsigned int mode;

	/* Disable interrupts */
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	atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
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	mode = atmel_uart_readl(port, ATMEL_US_MR);
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	/* Resetting serial mode to RS232 (0x0) */
	mode &= ~ATMEL_US_USMODE;

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	port->rs485 = *rs485conf;
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	if (rs485conf->flags & SER_RS485_ENABLED) {
		dev_dbg(port->dev, "Setting UART to RS485\n");
		atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
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		atmel_uart_writel(port, ATMEL_US_TTGR,
				  rs485conf->delay_rts_after_send);
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		mode |= ATMEL_US_USMODE_RS485;
	} else {
		dev_dbg(port->dev, "Setting UART to RS232\n");
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		if (atmel_use_pdc_tx(port))
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			atmel_port->tx_done_mask = ATMEL_US_ENDTX |
				ATMEL_US_TXBUFE;
		else
			atmel_port->tx_done_mask = ATMEL_US_TXRDY;
	}
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	atmel_uart_writel(port, ATMEL_US_MR, mode);
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	/* Enable interrupts */
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	atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
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	return 0;
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}

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/*
 * Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
 */
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static u_int atmel_tx_empty(struct uart_port *port)
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{
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	return (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXEMPTY) ?
		TIOCSER_TEMT :
		0;
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}

/*
 * Set state of the modem control output lines
 */
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static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
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{
	unsigned int control = 0;
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	unsigned int mode = atmel_uart_readl(port, ATMEL_US_MR);
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	unsigned int rts_paused, rts_ready;
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
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	/* override mode to RS485 if needed, otherwise keep the current mode */
	if (port->rs485.flags & SER_RS485_ENABLED) {
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		atmel_uart_writel(port, ATMEL_US_TTGR,
				  port->rs485.delay_rts_after_send);
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		mode &= ~ATMEL_US_USMODE;
		mode |= ATMEL_US_USMODE_RS485;
	}

	/* set the RTS line state according to the mode */
	if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
		/* force RTS line to high level */
		rts_paused = ATMEL_US_RTSEN;

		/* give the control of the RTS line back to the hardware */
		rts_ready = ATMEL_US_RTSDIS;
	} else {
		/* force RTS line to high level */
		rts_paused = ATMEL_US_RTSDIS;

		/* force RTS line to low level */
		rts_ready = ATMEL_US_RTSEN;
	}

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	if (mctrl & TIOCM_RTS)
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		control |= rts_ready;
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	else
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		control |= rts_paused;
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	if (mctrl & TIOCM_DTR)
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		control |= ATMEL_US_DTREN;
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	else
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		control |= ATMEL_US_DTRDIS;
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	atmel_uart_writel(port, ATMEL_US_CR, control);
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	mctrl_gpio_set(atmel_port->gpios, mctrl);

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	/* Local loopback mode? */
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	mode &= ~ATMEL_US_CHMODE;
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	if (mctrl & TIOCM_LOOP)
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		mode |= ATMEL_US_CHMODE_LOC_LOOP;
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	else
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		mode |= ATMEL_US_CHMODE_NORMAL;
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	atmel_uart_writel(port, ATMEL_US_MR, mode);
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}

/*
 * Get state of the modem control input lines
 */
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static u_int atmel_get_mctrl(struct uart_port *port)
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{
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	unsigned int ret = 0, status;
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	status = atmel_uart_readl(port, ATMEL_US_CSR);
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	/*
	 * The control signals are active low.
	 */
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	if (!(status & ATMEL_US_DCD))
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		ret |= TIOCM_CD;
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	if (!(status & ATMEL_US_CTS))
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		ret |= TIOCM_CTS;
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	if (!(status & ATMEL_US_DSR))
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		ret |= TIOCM_DSR;
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	if (!(status & ATMEL_US_RI))
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		ret |= TIOCM_RI;

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	return mctrl_gpio_get(atmel_port->gpios, &ret);
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}

/*
 * Stop transmitting.
 */
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static void atmel_stop_tx(struct uart_port *port)
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{
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

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	if (atmel_use_pdc_tx(port)) {
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		/* disable PDC transmit */
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		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
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	}
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	/*
	 * Disable the transmitter.
	 * This is mandatory when DMA is used, otherwise the DMA buffer
	 * is fully transmitted.
	 */
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS);

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	/* Disable interrupts */
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	atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
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	if ((port->rs485.flags & SER_RS485_ENABLED) &&
	    !(port->rs485.flags & SER_RS485_RX_DURING_TX))
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		atmel_start_rx(port);
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}

/*
 * Start transmitting.
 */
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static void atmel_start_tx(struct uart_port *port)
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{
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

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	if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR)
				       & ATMEL_PDC_TXTEN))
		/* The transmitter is already running.  Yes, we
		   really need this.*/
		return;
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	if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
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		if ((port->rs485.flags & SER_RS485_ENABLED) &&
		    !(port->rs485.flags & SER_RS485_RX_DURING_TX))
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			atmel_stop_rx(port);

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	if (atmel_use_pdc_tx(port))
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		/* re-enable PDC transmit */
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		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
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	/* Enable interrupts */
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	atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
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	/* re-enable the transmitter */
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
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}

/*
 * start receiving - port is in process of being opened.
 */
static void atmel_start_rx(struct uart_port *port)
{
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	/* reset status and receiver */
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
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	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXEN);
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	if (atmel_use_pdc_rx(port)) {
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		/* enable PDC controller */
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		atmel_uart_writel(port, ATMEL_US_IER,
				  ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
				  port->read_status_mask);
		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
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	} else {
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		atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY);
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	}
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}

/*
 * Stop receiving - port is in process of being closed.
 */
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static void atmel_stop_rx(struct uart_port *port)
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{
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	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RXDIS);
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	if (atmel_use_pdc_rx(port)) {
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		/* disable PDC receive */
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		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTDIS);
		atmel_uart_writel(port, ATMEL_US_IDR,
				  ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
				  port->read_status_mask);
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	} else {
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		atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXRDY);
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	}
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}

/*
 * Enable modem status interrupts
 */
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static void atmel_enable_ms(struct uart_port *port)
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{
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	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	uint32_t ier = 0;

	/*
	 * Interrupt should not be enabled twice
	 */
	if (atmel_port->ms_irq_enabled)
		return;

	atmel_port->ms_irq_enabled = true;

595
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
596 597
		ier |= ATMEL_US_CTSIC;

598
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))
599 600
		ier |= ATMEL_US_DSRIC;

601
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))
602 603
		ier |= ATMEL_US_RIIC;

604
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))
605 606
		ier |= ATMEL_US_DCDIC;

607
	atmel_uart_writel(port, ATMEL_US_IER, ier);
608 609

	mctrl_gpio_enable_ms(atmel_port->gpios);
610 611
}

612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627
/*
 * Disable modem status interrupts
 */
static void atmel_disable_ms(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	uint32_t idr = 0;

	/*
	 * Interrupt should not be disabled twice
	 */
	if (!atmel_port->ms_irq_enabled)
		return;

	atmel_port->ms_irq_enabled = false;

628 629 630
	mctrl_gpio_disable_ms(atmel_port->gpios);

	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
631 632
		idr |= ATMEL_US_CTSIC;

633
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DSR))
634 635
		idr |= ATMEL_US_DSRIC;

636
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_RI))
637 638
		idr |= ATMEL_US_RIIC;

639
	if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_DCD))
640 641
		idr |= ATMEL_US_DCDIC;

642
	atmel_uart_writel(port, ATMEL_US_IDR, idr);
643 644
}

645 646 647
/*
 * Control the transmission of a break signal
 */
648
static void atmel_break_ctl(struct uart_port *port, int break_state)
649 650
{
	if (break_state != 0)
651 652
		/* start break */
		atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTBRK);
653
	else
654 655
		/* stop break */
		atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STPBRK);
656 657
}

658 659 660 661 662 663 664
/*
 * Stores the incoming character in the ring buffer
 */
static void
atmel_buffer_rx_char(struct uart_port *port, unsigned int status,
		     unsigned int ch)
{
665
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682
	struct circ_buf *ring = &atmel_port->rx_ring;
	struct atmel_uart_char *c;

	if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE))
		/* Buffer overflow, ignore char */
		return;

	c = &((struct atmel_uart_char *)ring->buf)[ring->head];
	c->status	= status;
	c->ch		= ch;

	/* Make sure the character is stored before we update head. */
	smp_wmb();

	ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1);
}

C
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683 684 685 686 687 688
/*
 * Deal with parity, framing and overrun errors.
 */
static void atmel_pdc_rxerr(struct uart_port *port, unsigned int status)
{
	/* clear error */
689
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
C
Chip Coldwell 已提交
690 691 692 693 694 695 696 697 698 699 700 701 702 703

	if (status & ATMEL_US_RXBRK) {
		/* ignore side-effect */
		status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);
		port->icount.brk++;
	}
	if (status & ATMEL_US_PARE)
		port->icount.parity++;
	if (status & ATMEL_US_FRAME)
		port->icount.frame++;
	if (status & ATMEL_US_OVRE)
		port->icount.overrun++;
}

704 705 706
/*
 * Characters received (called from interrupt handler)
 */
707
static void atmel_rx_chars(struct uart_port *port)
708
{
709
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
710
	unsigned int status, ch;
711

712
	status = atmel_uart_readl(port, ATMEL_US_CSR);
713
	while (status & ATMEL_US_RXRDY) {
714
		ch = atmel_uart_read_char(port);
715 716 717 718 719

		/*
		 * note that the error handling code is
		 * out of the main execution path
		 */
720 721 722
		if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
				       | ATMEL_US_OVRE | ATMEL_US_RXBRK)
			     || atmel_port->break_active)) {
723

R
Remy Bohmer 已提交
724
			/* clear error */
725
			atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
726

727 728 729
			if (status & ATMEL_US_RXBRK
			    && !atmel_port->break_active) {
				atmel_port->break_active = 1;
730 731
				atmel_uart_writel(port, ATMEL_US_IER,
						  ATMEL_US_RXBRK);
732 733 734 735 736 737 738 739
			} else {
				/*
				 * This is either the end-of-break
				 * condition or we've received at
				 * least one character without RXBRK
				 * being set. In both cases, the next
				 * RXBRK will indicate start-of-break.
				 */
740 741
				atmel_uart_writel(port, ATMEL_US_IDR,
						  ATMEL_US_RXBRK);
742 743
				status &= ~ATMEL_US_RXBRK;
				atmel_port->break_active = 0;
744
			}
745 746
		}

747
		atmel_buffer_rx_char(port, status, ch);
748
		status = atmel_uart_readl(port, ATMEL_US_CSR);
749 750
	}

751
	atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
752 753 754
}

/*
755 756
 * Transmit characters (called from tasklet with TXRDY interrupt
 * disabled)
757
 */
758
static void atmel_tx_chars(struct uart_port *port)
759
{
A
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760
	struct circ_buf *xmit = &port->state->xmit;
761
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
762

763 764
	if (port->x_char &&
	    (atmel_uart_readl(port, ATMEL_US_CSR) & atmel_port->tx_done_mask)) {
765
		atmel_uart_write_char(port, port->x_char);
766 767 768
		port->icount.tx++;
		port->x_char = 0;
	}
769
	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
770 771
		return;

772 773
	while (atmel_uart_readl(port, ATMEL_US_CSR) &
	       atmel_port->tx_done_mask) {
774
		atmel_uart_write_char(port, xmit->buf[xmit->tail]);
775 776 777 778 779 780 781 782 783
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
		if (uart_circ_empty(xmit))
			break;
	}

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

784
	if (!uart_circ_empty(xmit))
785
		/* Enable interrupts */
786 787
		atmel_uart_writel(port, ATMEL_US_IER,
				  atmel_port->tx_done_mask);
788 789
}

E
Elen Song 已提交
790 791 792 793 794 795 796 797 798 799 800 801
static void atmel_complete_tx_dma(void *arg)
{
	struct atmel_uart_port *atmel_port = arg;
	struct uart_port *port = &atmel_port->uart;
	struct circ_buf *xmit = &port->state->xmit;
	struct dma_chan *chan = atmel_port->chan_tx;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);

	if (chan)
		dmaengine_terminate_all(chan);
802
	xmit->tail += atmel_port->tx_len;
E
Elen Song 已提交
803 804
	xmit->tail &= UART_XMIT_SIZE - 1;

805
	port->icount.tx += atmel_port->tx_len;
E
Elen Song 已提交
806 807 808 809 810 811 812 813 814 815

	spin_lock_irq(&atmel_port->lock_tx);
	async_tx_ack(atmel_port->desc_tx);
	atmel_port->cookie_tx = -EINVAL;
	atmel_port->desc_tx = NULL;
	spin_unlock_irq(&atmel_port->lock_tx);

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

816 817 818 819 820
	/*
	 * xmit is a circular buffer so, if we have just send data from
	 * xmit->tail to the end of xmit->buf, now we have to transmit the
	 * remaining data from the beginning of xmit->buf to xmit->head.
	 */
E
Elen Song 已提交
821
	if (!uart_circ_empty(xmit))
822
		atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
823 824 825 826 827
	else if ((port->rs485.flags & SER_RS485_ENABLED) &&
		 !(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
		/* DMA done, stop TX, start RX for RS485 */
		atmel_start_rx(port);
	}
E
Elen Song 已提交
828 829 830 831 832 833 834 835 836 837 838 839 840

	spin_unlock_irqrestore(&port->lock, flags);
}

static void atmel_release_tx_dma(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	struct dma_chan *chan = atmel_port->chan_tx;

	if (chan) {
		dmaengine_terminate_all(chan);
		dma_release_channel(chan);
		dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1,
841
				DMA_TO_DEVICE);
E
Elen Song 已提交
842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857
	}

	atmel_port->desc_tx = NULL;
	atmel_port->chan_tx = NULL;
	atmel_port->cookie_tx = -EINVAL;
}

/*
 * Called from tasklet with TXRDY interrupt is disabled.
 */
static void atmel_tx_dma(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	struct circ_buf *xmit = &port->state->xmit;
	struct dma_chan *chan = atmel_port->chan_tx;
	struct dma_async_tx_descriptor *desc;
858 859 860
	struct scatterlist sgl[2], *sg, *sg_tx = &atmel_port->sg_tx;
	unsigned int tx_len, part1_len, part2_len, sg_len;
	dma_addr_t phys_addr;
E
Elen Song 已提交
861 862 863 864 865 866 867 868 869 870 871 872 873 874 875

	/* Make sure we have an idle channel */
	if (atmel_port->desc_tx != NULL)
		return;

	if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
		/*
		 * DMA is idle now.
		 * Port xmit buffer is already mapped,
		 * and it is one page... Just adjust
		 * offsets and lengths. Since it is a circular buffer,
		 * we have to transmit till the end, and then the rest.
		 * Take the port lock to get a
		 * consistent xmit buffer state.
		 */
876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911
		tx_len = CIRC_CNT_TO_END(xmit->head,
					 xmit->tail,
					 UART_XMIT_SIZE);

		if (atmel_port->fifo_size) {
			/* multi data mode */
			part1_len = (tx_len & ~0x3); /* DWORD access */
			part2_len = (tx_len & 0x3); /* BYTE access */
		} else {
			/* single data (legacy) mode */
			part1_len = 0;
			part2_len = tx_len; /* BYTE access only */
		}

		sg_init_table(sgl, 2);
		sg_len = 0;
		phys_addr = sg_dma_address(sg_tx) + xmit->tail;
		if (part1_len) {
			sg = &sgl[sg_len++];
			sg_dma_address(sg) = phys_addr;
			sg_dma_len(sg) = part1_len;

			phys_addr += part1_len;
		}

		if (part2_len) {
			sg = &sgl[sg_len++];
			sg_dma_address(sg) = phys_addr;
			sg_dma_len(sg) = part2_len;
		}

		/*
		 * save tx_len so atmel_complete_tx_dma() will increase
		 * xmit->tail correctly
		 */
		atmel_port->tx_len = tx_len;
E
Elen Song 已提交
912 913

		desc = dmaengine_prep_slave_sg(chan,
914 915
					       sgl,
					       sg_len,
916 917 918
					       DMA_MEM_TO_DEV,
					       DMA_PREP_INTERRUPT |
					       DMA_CTRL_ACK);
E
Elen Song 已提交
919 920 921 922 923
		if (!desc) {
			dev_err(port->dev, "Failed to send via dma!\n");
			return;
		}

924
		dma_sync_sg_for_device(port->dev, sg_tx, 1, DMA_TO_DEVICE);
E
Elen Song 已提交
925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954

		atmel_port->desc_tx = desc;
		desc->callback = atmel_complete_tx_dma;
		desc->callback_param = atmel_port;
		atmel_port->cookie_tx = dmaengine_submit(desc);
	}

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);
}

static int atmel_prepare_tx_dma(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	dma_cap_mask_t		mask;
	struct dma_slave_config config;
	int ret, nent;

	dma_cap_zero(mask);
	dma_cap_set(DMA_SLAVE, mask);

	atmel_port->chan_tx = dma_request_slave_channel(port->dev, "tx");
	if (atmel_port->chan_tx == NULL)
		goto chan_err;
	dev_info(port->dev, "using %s for tx DMA transfers\n",
		dma_chan_name(atmel_port->chan_tx));

	spin_lock_init(&atmel_port->lock_tx);
	sg_init_table(&atmel_port->sg_tx, 1);
	/* UART circular tx buffer is an aligned page. */
955
	BUG_ON(!PAGE_ALIGNED(port->state->xmit.buf));
E
Elen Song 已提交
956 957 958
	sg_set_page(&atmel_port->sg_tx,
			virt_to_page(port->state->xmit.buf),
			UART_XMIT_SIZE,
959
			(unsigned long)port->state->xmit.buf & ~PAGE_MASK);
E
Elen Song 已提交
960 961 962
	nent = dma_map_sg(port->dev,
				&atmel_port->sg_tx,
				1,
963
				DMA_TO_DEVICE);
E
Elen Song 已提交
964 965 966 967 968

	if (!nent) {
		dev_dbg(port->dev, "need to release resource of dma\n");
		goto chan_err;
	} else {
969
		dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
E
Elen Song 已提交
970 971
			sg_dma_len(&atmel_port->sg_tx),
			port->state->xmit.buf,
972
			&sg_dma_address(&atmel_port->sg_tx));
E
Elen Song 已提交
973 974 975 976 977
	}

	/* Configure the slave DMA */
	memset(&config, 0, sizeof(config));
	config.direction = DMA_MEM_TO_DEV;
978 979 980
	config.dst_addr_width = (atmel_port->fifo_size) ?
				DMA_SLAVE_BUSWIDTH_4_BYTES :
				DMA_SLAVE_BUSWIDTH_1_BYTE;
E
Elen Song 已提交
981
	config.dst_addr = port->mapbase + ATMEL_US_THR;
982
	config.dst_maxburst = 1;
E
Elen Song 已提交
983

984 985
	ret = dmaengine_slave_config(atmel_port->chan_tx,
				     &config);
E
Elen Song 已提交
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000
	if (ret) {
		dev_err(port->dev, "DMA tx slave configuration failed\n");
		goto chan_err;
	}

	return 0;

chan_err:
	dev_err(port->dev, "TX channel not available, switch to pio\n");
	atmel_port->use_dma_tx = 0;
	if (atmel_port->chan_tx)
		atmel_release_tx_dma(port);
	return -EINVAL;
}

E
Elen Song 已提交
1001 1002 1003 1004 1005
static void atmel_complete_rx_dma(void *arg)
{
	struct uart_port *port = arg;
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

1006
	atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
E
Elen Song 已提交
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017
}

static void atmel_release_rx_dma(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	struct dma_chan *chan = atmel_port->chan_rx;

	if (chan) {
		dmaengine_terminate_all(chan);
		dma_release_channel(chan);
		dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1,
1018
				DMA_FROM_DEVICE);
E
Elen Song 已提交
1019 1020 1021 1022 1023 1024 1025 1026 1027 1028
	}

	atmel_port->desc_rx = NULL;
	atmel_port->chan_rx = NULL;
	atmel_port->cookie_rx = -EINVAL;
}

static void atmel_rx_from_dma(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1029
	struct tty_port *tport = &port->state->port;
E
Elen Song 已提交
1030 1031 1032 1033
	struct circ_buf *ring = &atmel_port->rx_ring;
	struct dma_chan *chan = atmel_port->chan_rx;
	struct dma_tx_state state;
	enum dma_status dmastat;
1034
	size_t count;
E
Elen Song 已提交
1035 1036 1037


	/* Reset the UART timeout early so that we don't miss one */
1038
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
E
Elen Song 已提交
1039 1040 1041 1042 1043 1044
	dmastat = dmaengine_tx_status(chan,
				atmel_port->cookie_rx,
				&state);
	/* Restart a new tasklet if DMA status is error */
	if (dmastat == DMA_ERROR) {
		dev_dbg(port->dev, "Get residue error, restart tasklet\n");
1045
		atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
1046
		atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
E
Elen Song 已提交
1047 1048 1049
		return;
	}

1050 1051 1052 1053
	/* CPU claims ownership of RX DMA buffer */
	dma_sync_sg_for_cpu(port->dev,
			    &atmel_port->sg_rx,
			    1,
1054
			    DMA_FROM_DEVICE);
1055 1056 1057 1058 1059 1060 1061 1062 1063 1064

	/*
	 * ring->head points to the end of data already written by the DMA.
	 * ring->tail points to the beginning of data to be read by the
	 * framework.
	 * The current transfer size should not be larger than the dma buffer
	 * length.
	 */
	ring->head = sg_dma_len(&atmel_port->sg_rx) - state.residue;
	BUG_ON(ring->head > sg_dma_len(&atmel_port->sg_rx));
E
Elen Song 已提交
1065
	/*
1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
	 * At this point ring->head may point to the first byte right after the
	 * last byte of the dma buffer:
	 * 0 <= ring->head <= sg_dma_len(&atmel_port->sg_rx)
	 *
	 * However ring->tail must always points inside the dma buffer:
	 * 0 <= ring->tail <= sg_dma_len(&atmel_port->sg_rx) - 1
	 *
	 * Since we use a ring buffer, we have to handle the case
	 * where head is lower than tail. In such a case, we first read from
	 * tail to the end of the buffer then reset tail.
E
Elen Song 已提交
1076
	 */
1077 1078
	if (ring->head < ring->tail) {
		count = sg_dma_len(&atmel_port->sg_rx) - ring->tail;
E
Elen Song 已提交
1079

1080 1081 1082 1083
		tty_insert_flip_string(tport, ring->buf + ring->tail, count);
		ring->tail = 0;
		port->icount.rx += count;
	}
E
Elen Song 已提交
1084

1085 1086 1087
	/* Finally we read data from tail to head */
	if (ring->tail < ring->head) {
		count = ring->head - ring->tail;
E
Elen Song 已提交
1088

1089 1090 1091 1092 1093
		tty_insert_flip_string(tport, ring->buf + ring->tail, count);
		/* Wrap ring->head if needed */
		if (ring->head >= sg_dma_len(&atmel_port->sg_rx))
			ring->head = 0;
		ring->tail = ring->head;
E
Elen Song 已提交
1094 1095 1096
		port->icount.rx += count;
	}

1097 1098 1099 1100
	/* USART retreives ownership of RX DMA buffer */
	dma_sync_sg_for_device(port->dev,
			       &atmel_port->sg_rx,
			       1,
1101
			       DMA_FROM_DEVICE);
1102 1103 1104 1105 1106 1107 1108 1109 1110

	/*
	 * Drop the lock here since it might end up calling
	 * uart_start(), which takes the lock.
	 */
	spin_unlock(&port->lock);
	tty_flip_buffer_push(tport);
	spin_lock(&port->lock);

1111
	atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
E
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}

static int atmel_prepare_rx_dma(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	struct dma_async_tx_descriptor *desc;
	dma_cap_mask_t		mask;
	struct dma_slave_config config;
	struct circ_buf		*ring;
	int ret, nent;

	ring = &atmel_port->rx_ring;

	dma_cap_zero(mask);
	dma_cap_set(DMA_CYCLIC, mask);

	atmel_port->chan_rx = dma_request_slave_channel(port->dev, "rx");
	if (atmel_port->chan_rx == NULL)
		goto chan_err;
	dev_info(port->dev, "using %s for rx DMA transfers\n",
		dma_chan_name(atmel_port->chan_rx));

	spin_lock_init(&atmel_port->lock_rx);
	sg_init_table(&atmel_port->sg_rx, 1);
	/* UART circular rx buffer is an aligned page. */
1137
	BUG_ON(!PAGE_ALIGNED(ring->buf));
E
Elen Song 已提交
1138
	sg_set_page(&atmel_port->sg_rx,
1139
		    virt_to_page(ring->buf),
1140
		    sizeof(struct atmel_uart_char) * ATMEL_SERIAL_RINGSIZE,
1141
		    (unsigned long)ring->buf & ~PAGE_MASK);
1142 1143 1144 1145
	nent = dma_map_sg(port->dev,
			  &atmel_port->sg_rx,
			  1,
			  DMA_FROM_DEVICE);
E
Elen Song 已提交
1146 1147 1148 1149 1150

	if (!nent) {
		dev_dbg(port->dev, "need to release resource of dma\n");
		goto chan_err;
	} else {
1151
		dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
E
Elen Song 已提交
1152 1153
			sg_dma_len(&atmel_port->sg_rx),
			ring->buf,
1154
			&sg_dma_address(&atmel_port->sg_rx));
E
Elen Song 已提交
1155 1156 1157 1158 1159 1160 1161
	}

	/* Configure the slave DMA */
	memset(&config, 0, sizeof(config));
	config.direction = DMA_DEV_TO_MEM;
	config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
	config.src_addr = port->mapbase + ATMEL_US_RHR;
1162
	config.src_maxburst = 1;
E
Elen Song 已提交
1163

1164 1165
	ret = dmaengine_slave_config(atmel_port->chan_rx,
				     &config);
E
Elen Song 已提交
1166 1167 1168 1169 1170 1171 1172 1173 1174
	if (ret) {
		dev_err(port->dev, "DMA rx slave configuration failed\n");
		goto chan_err;
	}
	/*
	 * Prepare a cyclic dma transfer, assign 2 descriptors,
	 * each one is half ring buffer size
	 */
	desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx,
1175 1176 1177 1178 1179
					 sg_dma_address(&atmel_port->sg_rx),
					 sg_dma_len(&atmel_port->sg_rx),
					 sg_dma_len(&atmel_port->sg_rx)/2,
					 DMA_DEV_TO_MEM,
					 DMA_PREP_INTERRUPT);
E
Elen Song 已提交
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
	desc->callback = atmel_complete_rx_dma;
	desc->callback_param = port;
	atmel_port->desc_rx = desc;
	atmel_port->cookie_rx = dmaengine_submit(desc);

	return 0;

chan_err:
	dev_err(port->dev, "RX channel not available, switch to pio\n");
	atmel_port->use_dma_rx = 0;
	if (atmel_port->chan_rx)
		atmel_release_rx_dma(port);
	return -EINVAL;
}

1195 1196 1197 1198 1199
static void atmel_uart_timer_callback(unsigned long data)
{
	struct uart_port *port = (void *)data;
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

1200 1201 1202 1203 1204
	if (!atomic_read(&atmel_port->tasklet_shutdown)) {
		tasklet_schedule(&atmel_port->tasklet_rx);
		mod_timer(&atmel_port->uart_timer,
			  jiffies + uart_poll_timeout(port));
	}
1205 1206
}

R
Remy Bohmer 已提交
1207 1208 1209 1210 1211 1212
/*
 * receive interrupt handler.
 */
static void
atmel_handle_receive(struct uart_port *port, unsigned int pending)
{
1213
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
R
Remy Bohmer 已提交
1214

1215
	if (atmel_use_pdc_rx(port)) {
C
Chip Coldwell 已提交
1216 1217 1218 1219 1220 1221 1222 1223
		/*
		 * PDC receive. Just schedule the tasklet and let it
		 * figure out the details.
		 *
		 * TODO: We're not handling error flags correctly at
		 * the moment.
		 */
		if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {
1224 1225
			atmel_uart_writel(port, ATMEL_US_IDR,
					  (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT));
1226 1227
			atmel_tasklet_schedule(atmel_port,
					       &atmel_port->tasklet_rx);
C
Chip Coldwell 已提交
1228 1229 1230 1231 1232 1233 1234
		}

		if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |
				ATMEL_US_FRAME | ATMEL_US_PARE))
			atmel_pdc_rxerr(port, pending);
	}

E
Elen Song 已提交
1235 1236
	if (atmel_use_dma_rx(port)) {
		if (pending & ATMEL_US_TIMEOUT) {
1237 1238
			atmel_uart_writel(port, ATMEL_US_IDR,
					  ATMEL_US_TIMEOUT);
1239 1240
			atmel_tasklet_schedule(atmel_port,
					       &atmel_port->tasklet_rx);
E
Elen Song 已提交
1241 1242 1243
		}
	}

R
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1244 1245 1246 1247 1248 1249 1250 1251
	/* Interrupt receive */
	if (pending & ATMEL_US_RXRDY)
		atmel_rx_chars(port);
	else if (pending & ATMEL_US_RXBRK) {
		/*
		 * End of break detected. If it came along with a
		 * character, atmel_rx_chars will handle it.
		 */
1252 1253
		atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
		atmel_uart_writel(port, ATMEL_US_IDR, ATMEL_US_RXBRK);
R
Remy Bohmer 已提交
1254 1255 1256 1257 1258
		atmel_port->break_active = 0;
	}
}

/*
1259
 * transmit interrupt handler. (Transmit is IRQF_NODELAY safe)
R
Remy Bohmer 已提交
1260 1261 1262 1263
 */
static void
atmel_handle_transmit(struct uart_port *port, unsigned int pending)
{
1264
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1265

1266 1267
	if (pending & atmel_port->tx_done_mask) {
		/* Either PDC or interrupt transmission */
1268 1269
		atmel_uart_writel(port, ATMEL_US_IDR,
				  atmel_port->tx_done_mask);
1270
		atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
1271
	}
R
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1272 1273 1274 1275 1276 1277 1278 1279 1280
}

/*
 * status flags interrupt handler.
 */
static void
atmel_handle_status(struct uart_port *port, unsigned int pending,
		    unsigned int status)
{
1281
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1282
	unsigned int status_change;
1283

R
Remy Bohmer 已提交
1284
	if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC
1285
				| ATMEL_US_CTSIC)) {
1286
		status_change = status ^ atmel_port->irq_status_prev;
1287
		atmel_port->irq_status_prev = status;
1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302

		if (status_change & (ATMEL_US_RI | ATMEL_US_DSR
					| ATMEL_US_DCD | ATMEL_US_CTS)) {
			/* TODO: All reads to CSR will clear these interrupts! */
			if (status_change & ATMEL_US_RI)
				port->icount.rng++;
			if (status_change & ATMEL_US_DSR)
				port->icount.dsr++;
			if (status_change & ATMEL_US_DCD)
				uart_handle_dcd_change(port, !(status & ATMEL_US_DCD));
			if (status_change & ATMEL_US_CTS)
				uart_handle_cts_change(port, !(status & ATMEL_US_CTS));

			wake_up_interruptible(&port->state->port.delta_msr_wait);
		}
1303
	}
R
Remy Bohmer 已提交
1304 1305
}

1306 1307 1308
/*
 * Interrupt handler
 */
1309
static irqreturn_t atmel_interrupt(int irq, void *dev_id)
1310 1311
{
	struct uart_port *port = dev_id;
1312
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1313
	unsigned int status, pending, mask, pass_counter = 0;
1314

1315 1316
	spin_lock(&atmel_port->lock_suspended);

C
Chip Coldwell 已提交
1317
	do {
1318
		status = atmel_get_lines_status(port);
1319
		mask = atmel_uart_readl(port, ATMEL_US_IMR);
1320
		pending = status & mask;
C
Chip Coldwell 已提交
1321 1322 1323
		if (!pending)
			break;

1324 1325 1326
		if (atmel_port->suspended) {
			atmel_port->pending |= pending;
			atmel_port->pending_status = status;
1327
			atmel_uart_writel(port, ATMEL_US_IDR, mask);
1328 1329 1330 1331
			pm_system_wakeup();
			break;
		}

R
Remy Bohmer 已提交
1332 1333 1334
		atmel_handle_receive(port, pending);
		atmel_handle_status(port, pending, status);
		atmel_handle_transmit(port, pending);
C
Chip Coldwell 已提交
1335
	} while (pass_counter++ < ATMEL_ISR_PASS_LIMIT);
1336

1337 1338
	spin_unlock(&atmel_port->lock_suspended);

1339
	return pass_counter ? IRQ_HANDLED : IRQ_NONE;
C
Chip Coldwell 已提交
1340
}
1341

1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352
static void atmel_release_tx_pdc(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;

	dma_unmap_single(port->dev,
			 pdc->dma_addr,
			 pdc->dma_size,
			 DMA_TO_DEVICE);
}

C
Chip Coldwell 已提交
1353 1354 1355
/*
 * Called from tasklet with ENDTX and TXBUFE interrupts disabled.
 */
1356
static void atmel_tx_pdc(struct uart_port *port)
C
Chip Coldwell 已提交
1357
{
1358
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
A
Alan Cox 已提交
1359
	struct circ_buf *xmit = &port->state->xmit;
C
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1360 1361 1362
	struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
	int count;

1363
	/* nothing left to transmit? */
1364
	if (atmel_uart_readl(port, ATMEL_PDC_TCR))
1365 1366
		return;

C
Chip Coldwell 已提交
1367 1368 1369 1370 1371 1372
	xmit->tail += pdc->ofs;
	xmit->tail &= UART_XMIT_SIZE - 1;

	port->icount.tx += pdc->ofs;
	pdc->ofs = 0;

1373
	/* more to transmit - setup next transfer */
C
Chip Coldwell 已提交
1374

1375
	/* disable PDC transmit */
1376
	atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
1377

I
Itai Levi 已提交
1378
	if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
C
Chip Coldwell 已提交
1379 1380 1381 1382 1383 1384 1385 1386
		dma_sync_single_for_device(port->dev,
					   pdc->dma_addr,
					   pdc->dma_size,
					   DMA_TO_DEVICE);

		count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
		pdc->ofs = count;

1387 1388 1389
		atmel_uart_writel(port, ATMEL_PDC_TPR,
				  pdc->dma_addr + xmit->tail);
		atmel_uart_writel(port, ATMEL_PDC_TCR, count);
1390
		/* re-enable PDC transmit */
1391
		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
1392
		/* Enable interrupts */
1393 1394
		atmel_uart_writel(port, ATMEL_US_IER,
				  atmel_port->tx_done_mask);
1395
	} else {
1396 1397
		if ((port->rs485.flags & SER_RS485_ENABLED) &&
		    !(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
1398 1399 1400
			/* DMA done, stop TX, start RX for RS485 */
			atmel_start_rx(port);
		}
1401
	}
C
Chip Coldwell 已提交
1402 1403 1404

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);
1405 1406
}

1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
static int atmel_prepare_tx_pdc(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
	struct circ_buf *xmit = &port->state->xmit;

	pdc->buf = xmit->buf;
	pdc->dma_addr = dma_map_single(port->dev,
					pdc->buf,
					UART_XMIT_SIZE,
					DMA_TO_DEVICE);
	pdc->dma_size = UART_XMIT_SIZE;
	pdc->ofs = 0;

	return 0;
}

1424 1425
static void atmel_rx_from_ring(struct uart_port *port)
{
1426
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487
	struct circ_buf *ring = &atmel_port->rx_ring;
	unsigned int flg;
	unsigned int status;

	while (ring->head != ring->tail) {
		struct atmel_uart_char c;

		/* Make sure c is loaded after head. */
		smp_rmb();

		c = ((struct atmel_uart_char *)ring->buf)[ring->tail];

		ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1);

		port->icount.rx++;
		status = c.status;
		flg = TTY_NORMAL;

		/*
		 * note that the error handling code is
		 * out of the main execution path
		 */
		if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME
				       | ATMEL_US_OVRE | ATMEL_US_RXBRK))) {
			if (status & ATMEL_US_RXBRK) {
				/* ignore side-effect */
				status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME);

				port->icount.brk++;
				if (uart_handle_break(port))
					continue;
			}
			if (status & ATMEL_US_PARE)
				port->icount.parity++;
			if (status & ATMEL_US_FRAME)
				port->icount.frame++;
			if (status & ATMEL_US_OVRE)
				port->icount.overrun++;

			status &= port->read_status_mask;

			if (status & ATMEL_US_RXBRK)
				flg = TTY_BREAK;
			else if (status & ATMEL_US_PARE)
				flg = TTY_PARITY;
			else if (status & ATMEL_US_FRAME)
				flg = TTY_FRAME;
		}


		if (uart_handle_sysrq_char(port, c.ch))
			continue;

		uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg);
	}

	/*
	 * Drop the lock here since it might end up calling
	 * uart_start(), which takes the lock.
	 */
	spin_unlock(&port->lock);
J
Jiri Slaby 已提交
1488
	tty_flip_buffer_push(&port->state->port);
1489 1490 1491
	spin_lock(&port->lock);
}

1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507
static void atmel_release_rx_pdc(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	int i;

	for (i = 0; i < 2; i++) {
		struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];

		dma_unmap_single(port->dev,
				 pdc->dma_addr,
				 pdc->dma_size,
				 DMA_FROM_DEVICE);
		kfree(pdc->buf);
	}
}

1508
static void atmel_rx_from_pdc(struct uart_port *port)
C
Chip Coldwell 已提交
1509
{
1510
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
J
Jiri Slaby 已提交
1511
	struct tty_port *tport = &port->state->port;
C
Chip Coldwell 已提交
1512 1513 1514 1515 1516 1517 1518 1519
	struct atmel_dma_buffer *pdc;
	int rx_idx = atmel_port->pdc_rx_idx;
	unsigned int head;
	unsigned int tail;
	unsigned int count;

	do {
		/* Reset the UART timeout early so that we don't miss one */
1520
		atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
C
Chip Coldwell 已提交
1521 1522

		pdc = &atmel_port->pdc_rx[rx_idx];
1523
		head = atmel_uart_readl(port, ATMEL_PDC_RPR) - pdc->dma_addr;
C
Chip Coldwell 已提交
1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549
		tail = pdc->ofs;

		/* If the PDC has switched buffers, RPR won't contain
		 * any address within the current buffer. Since head
		 * is unsigned, we just need a one-way comparison to
		 * find out.
		 *
		 * In this case, we just need to consume the entire
		 * buffer and resubmit it for DMA. This will clear the
		 * ENDRX bit as well, so that we can safely re-enable
		 * all interrupts below.
		 */
		head = min(head, pdc->dma_size);

		if (likely(head != tail)) {
			dma_sync_single_for_cpu(port->dev, pdc->dma_addr,
					pdc->dma_size, DMA_FROM_DEVICE);

			/*
			 * head will only wrap around when we recycle
			 * the DMA buffer, and when that happens, we
			 * explicitly set tail to 0. So head will
			 * always be greater than tail.
			 */
			count = head - tail;

J
Jiri Slaby 已提交
1550 1551
			tty_insert_flip_string(tport, pdc->buf + pdc->ofs,
						count);
C
Chip Coldwell 已提交
1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565

			dma_sync_single_for_device(port->dev, pdc->dma_addr,
					pdc->dma_size, DMA_FROM_DEVICE);

			port->icount.rx += count;
			pdc->ofs = head;
		}

		/*
		 * If the current buffer is full, we need to check if
		 * the next one contains any additional data.
		 */
		if (head >= pdc->dma_size) {
			pdc->ofs = 0;
1566 1567
			atmel_uart_writel(port, ATMEL_PDC_RNPR, pdc->dma_addr);
			atmel_uart_writel(port, ATMEL_PDC_RNCR, pdc->dma_size);
C
Chip Coldwell 已提交
1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578

			rx_idx = !rx_idx;
			atmel_port->pdc_rx_idx = rx_idx;
		}
	} while (head >= pdc->dma_size);

	/*
	 * Drop the lock here since it might end up calling
	 * uart_start(), which takes the lock.
	 */
	spin_unlock(&port->lock);
J
Jiri Slaby 已提交
1579
	tty_flip_buffer_push(tport);
C
Chip Coldwell 已提交
1580 1581
	spin_lock(&port->lock);

1582 1583
	atmel_uart_writel(port, ATMEL_US_IER,
			  ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
C
Chip Coldwell 已提交
1584 1585
}

1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615
static int atmel_prepare_rx_pdc(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	int i;

	for (i = 0; i < 2; i++) {
		struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];

		pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);
		if (pdc->buf == NULL) {
			if (i != 0) {
				dma_unmap_single(port->dev,
					atmel_port->pdc_rx[0].dma_addr,
					PDC_BUFFER_SIZE,
					DMA_FROM_DEVICE);
				kfree(atmel_port->pdc_rx[0].buf);
			}
			atmel_port->use_pdc_rx = 0;
			return -ENOMEM;
		}
		pdc->dma_addr = dma_map_single(port->dev,
						pdc->buf,
						PDC_BUFFER_SIZE,
						DMA_FROM_DEVICE);
		pdc->dma_size = PDC_BUFFER_SIZE;
		pdc->ofs = 0;
	}

	atmel_port->pdc_rx_idx = 0;

1616 1617
	atmel_uart_writel(port, ATMEL_PDC_RPR, atmel_port->pdc_rx[0].dma_addr);
	atmel_uart_writel(port, ATMEL_PDC_RCR, PDC_BUFFER_SIZE);
1618

1619 1620 1621
	atmel_uart_writel(port, ATMEL_PDC_RNPR,
			  atmel_port->pdc_rx[1].dma_addr);
	atmel_uart_writel(port, ATMEL_PDC_RNCR, PDC_BUFFER_SIZE);
1622 1623 1624 1625

	return 0;
}

1626 1627 1628
/*
 * tasklet handling tty stuff outside the interrupt handler.
 */
1629
static void atmel_tasklet_rx_func(unsigned long data)
1630 1631
{
	struct uart_port *port = (struct uart_port *)data;
1632
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1633 1634 1635

	/* The interrupt handler does not take the lock */
	spin_lock(&port->lock);
1636
	atmel_port->schedule_rx(port);
1637 1638
	spin_unlock(&port->lock);
}
1639

1640 1641 1642 1643 1644 1645 1646 1647
static void atmel_tasklet_tx_func(unsigned long data)
{
	struct uart_port *port = (struct uart_port *)data;
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

	/* The interrupt handler does not take the lock */
	spin_lock(&port->lock);
	atmel_port->schedule_tx(port);
1648 1649 1650
	spin_unlock(&port->lock);
}

1651
static void atmel_init_property(struct atmel_uart_port *atmel_port,
1652 1653 1654
				struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
J
Jingoo Han 已提交
1655
	struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev);
1656 1657 1658

	if (np) {
		/* DMA/PDC usage specification */
1659 1660
		if (of_property_read_bool(np, "atmel,use-dma-rx")) {
			if (of_property_read_bool(np, "dmas")) {
1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671
				atmel_port->use_dma_rx  = true;
				atmel_port->use_pdc_rx  = false;
			} else {
				atmel_port->use_dma_rx  = false;
				atmel_port->use_pdc_rx  = true;
			}
		} else {
			atmel_port->use_dma_rx  = false;
			atmel_port->use_pdc_rx  = false;
		}

1672 1673
		if (of_property_read_bool(np, "atmel,use-dma-tx")) {
			if (of_property_read_bool(np, "dmas")) {
1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693
				atmel_port->use_dma_tx  = true;
				atmel_port->use_pdc_tx  = false;
			} else {
				atmel_port->use_dma_tx  = false;
				atmel_port->use_pdc_tx  = true;
			}
		} else {
			atmel_port->use_dma_tx  = false;
			atmel_port->use_pdc_tx  = false;
		}

	} else {
		atmel_port->use_pdc_rx  = pdata->use_dma_rx;
		atmel_port->use_pdc_tx  = pdata->use_dma_tx;
		atmel_port->use_dma_rx  = false;
		atmel_port->use_dma_tx  = false;
	}

}

1694
static void atmel_init_rs485(struct uart_port *port,
1695 1696 1697
				struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
J
Jingoo Han 已提交
1698
	struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev);
1699 1700

	if (np) {
J
Jiri Slaby 已提交
1701
		struct serial_rs485 *rs485conf = &port->rs485;
1702 1703 1704 1705 1706 1707 1708
		u32 rs485_delay[2];
		/* rs485 properties */
		if (of_property_read_u32_array(np, "rs485-rts-delay",
					rs485_delay, 2) == 0) {
			rs485conf->delay_rts_before_send = rs485_delay[0];
			rs485conf->delay_rts_after_send = rs485_delay[1];
			rs485conf->flags = 0;
J
Jiri Slaby 已提交
1709
		}
1710 1711 1712 1713 1714 1715 1716 1717

		if (of_get_property(np, "rs485-rx-during-tx", NULL))
			rs485conf->flags |= SER_RS485_RX_DURING_TX;

		if (of_get_property(np, "linux,rs485-enabled-at-boot-time",
								NULL))
			rs485conf->flags |= SER_RS485_ENABLED;
	} else {
1718
		port->rs485       = pdata->rs485;
1719 1720 1721 1722
	}

}

1723 1724 1725 1726
static void atmel_set_ops(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

E
Elen Song 已提交
1727 1728 1729 1730 1731
	if (atmel_use_dma_rx(port)) {
		atmel_port->prepare_rx = &atmel_prepare_rx_dma;
		atmel_port->schedule_rx = &atmel_rx_from_dma;
		atmel_port->release_rx = &atmel_release_rx_dma;
	} else if (atmel_use_pdc_rx(port)) {
1732 1733 1734 1735 1736 1737 1738 1739 1740
		atmel_port->prepare_rx = &atmel_prepare_rx_pdc;
		atmel_port->schedule_rx = &atmel_rx_from_pdc;
		atmel_port->release_rx = &atmel_release_rx_pdc;
	} else {
		atmel_port->prepare_rx = NULL;
		atmel_port->schedule_rx = &atmel_rx_from_ring;
		atmel_port->release_rx = NULL;
	}

E
Elen Song 已提交
1741 1742 1743 1744 1745
	if (atmel_use_dma_tx(port)) {
		atmel_port->prepare_tx = &atmel_prepare_tx_dma;
		atmel_port->schedule_tx = &atmel_tx_dma;
		atmel_port->release_tx = &atmel_release_tx_dma;
	} else if (atmel_use_pdc_tx(port)) {
1746 1747 1748 1749 1750 1751 1752 1753 1754 1755
		atmel_port->prepare_tx = &atmel_prepare_tx_pdc;
		atmel_port->schedule_tx = &atmel_tx_pdc;
		atmel_port->release_tx = &atmel_release_tx_pdc;
	} else {
		atmel_port->prepare_tx = NULL;
		atmel_port->schedule_tx = &atmel_tx_chars;
		atmel_port->release_tx = NULL;
	}
}

1756 1757 1758
/*
 * Get ip name usart or uart
 */
1759
static void atmel_get_ip_name(struct uart_port *port)
1760 1761
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1762
	int name = atmel_uart_readl(port, ATMEL_US_NAME);
1763
	u32 version;
1764
	u32 usart, dbgu_uart, new_uart;
1765 1766 1767
	/* ASCII decoding for IP version */
	usart = 0x55534152;	/* USAR(T) */
	dbgu_uart = 0x44424755;	/* DBGU */
1768
	new_uart = 0x55415254;	/* UART */
1769

1770 1771
	/*
	 * Only USART devices from at91sam9260 SOC implement fractional
1772 1773 1774
	 * baudrate. It is available for all asynchronous modes, with the
	 * following restriction: the sampling clock's duty cycle is not
	 * constant.
1775 1776
	 */
	atmel_port->has_frac_baudrate = false;
1777
	atmel_port->has_hw_timer = false;
1778

1779 1780
	if (name == new_uart) {
		dev_dbg(port->dev, "Uart with hw timer");
1781
		atmel_port->has_hw_timer = true;
1782 1783 1784
		atmel_port->rtor = ATMEL_UA_RTOR;
	} else if (name == usart) {
		dev_dbg(port->dev, "Usart\n");
1785
		atmel_port->has_frac_baudrate = true;
1786 1787
		atmel_port->has_hw_timer = true;
		atmel_port->rtor = ATMEL_US_RTOR;
1788 1789
	} else if (name == dbgu_uart) {
		dev_dbg(port->dev, "Dbgu or uart without hw timer\n");
1790
	} else {
1791
		/* fallback for older SoCs: use version field */
1792
		version = atmel_uart_readl(port, ATMEL_US_VERSION);
1793 1794 1795 1796
		switch (version) {
		case 0x302:
		case 0x10213:
			dev_dbg(port->dev, "This version is usart\n");
1797
			atmel_port->has_frac_baudrate = true;
1798
			atmel_port->has_hw_timer = true;
1799
			atmel_port->rtor = ATMEL_US_RTOR;
1800 1801 1802 1803 1804 1805 1806 1807
			break;
		case 0x203:
		case 0x10202:
			dev_dbg(port->dev, "This version is uart\n");
			break;
		default:
			dev_err(port->dev, "Not supported ip name nor version, set to uart\n");
		}
1808 1809 1810
	}
}

1811 1812 1813
/*
 * Perform initialization and enable port for reception
 */
1814
static int atmel_startup(struct uart_port *port)
1815
{
1816
	struct platform_device *pdev = to_platform_device(port->dev);
1817
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
A
Alan Cox 已提交
1818
	struct tty_struct *tty = port->state->port.tty;
1819 1820 1821 1822 1823 1824 1825
	int retval;

	/*
	 * Ensure that no interrupts are enabled otherwise when
	 * request_irq() is called we could get stuck trying to
	 * handle an unexpected interrupt
	 */
1826
	atmel_uart_writel(port, ATMEL_US_IDR, -1);
1827
	atmel_port->ms_irq_enabled = false;
1828 1829 1830 1831

	/*
	 * Allocate the IRQ
	 */
1832 1833
	retval = request_irq(port->irq, atmel_interrupt,
			IRQF_SHARED | IRQF_COND_SUSPEND,
1834
			tty ? tty->name : "atmel_serial", port);
1835
	if (retval) {
1836
		dev_err(port->dev, "atmel_startup - Can't get irq\n");
1837 1838 1839
		return retval;
	}

1840 1841 1842 1843 1844
	atomic_set(&atmel_port->tasklet_shutdown, 0);
	tasklet_init(&atmel_port->tasklet_rx, atmel_tasklet_rx_func,
			(unsigned long)port);
	tasklet_init(&atmel_port->tasklet_tx, atmel_tasklet_tx_func,
			(unsigned long)port);
1845

C
Chip Coldwell 已提交
1846 1847 1848
	/*
	 * Initialize DMA (if necessary)
	 */
1849
	atmel_init_property(atmel_port, pdev);
1850
	atmel_set_ops(port);
1851

1852 1853 1854 1855
	if (atmel_port->prepare_rx) {
		retval = atmel_port->prepare_rx(port);
		if (retval < 0)
			atmel_set_ops(port);
C
Chip Coldwell 已提交
1856 1857
	}

1858 1859 1860 1861
	if (atmel_port->prepare_tx) {
		retval = atmel_port->prepare_tx(port);
		if (retval < 0)
			atmel_set_ops(port);
C
Chip Coldwell 已提交
1862
	}
1863

1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876
	/*
	 * Enable FIFO when available
	 */
	if (atmel_port->fifo_size) {
		unsigned int txrdym = ATMEL_US_ONE_DATA;
		unsigned int rxrdym = ATMEL_US_ONE_DATA;
		unsigned int fmr;

		atmel_uart_writel(port, ATMEL_US_CR,
				  ATMEL_US_FIFOEN |
				  ATMEL_US_RXFCLR |
				  ATMEL_US_TXFLCLR);

1877 1878 1879
		if (atmel_use_dma_tx(port))
			txrdym = ATMEL_US_FOUR_DATA;

1880 1881 1882 1883 1884 1885 1886 1887 1888 1889
		fmr = ATMEL_US_TXRDYM(txrdym) | ATMEL_US_RXRDYM(rxrdym);
		if (atmel_port->rts_high &&
		    atmel_port->rts_low)
			fmr |=	ATMEL_US_FRTSC |
				ATMEL_US_RXFTHRES(atmel_port->rts_high) |
				ATMEL_US_RXFTHRES2(atmel_port->rts_low);

		atmel_uart_writel(port, ATMEL_US_FMR, fmr);
	}

1890
	/* Save current CSR for comparison in atmel_tasklet_func() */
1891
	atmel_port->irq_status_prev = atmel_get_lines_status(port);
1892

1893 1894 1895
	/*
	 * Finally, enable the serial port
	 */
1896
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
R
Remy Bohmer 已提交
1897
	/* enable xmit & rcvr */
1898
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
1899

1900 1901 1902 1903
	setup_timer(&atmel_port->uart_timer,
			atmel_uart_timer_callback,
			(unsigned long)port);

1904
	if (atmel_use_pdc_rx(port)) {
C
Chip Coldwell 已提交
1905
		/* set UART timeout */
1906
		if (!atmel_port->has_hw_timer) {
1907 1908 1909 1910
			mod_timer(&atmel_port->uart_timer,
					jiffies + uart_poll_timeout(port));
		/* set USART timeout */
		} else {
1911 1912
			atmel_uart_writel(port, atmel_port->rtor,
					  PDC_RX_TIMEOUT);
1913
			atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
C
Chip Coldwell 已提交
1914

1915 1916
			atmel_uart_writel(port, ATMEL_US_IER,
					  ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
1917
		}
C
Chip Coldwell 已提交
1918
		/* enable PDC controller */
1919
		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_RXTEN);
E
Elen Song 已提交
1920
	} else if (atmel_use_dma_rx(port)) {
1921
		/* set UART timeout */
1922
		if (!atmel_port->has_hw_timer) {
1923 1924 1925 1926
			mod_timer(&atmel_port->uart_timer,
					jiffies + uart_poll_timeout(port));
		/* set USART timeout */
		} else {
1927 1928
			atmel_uart_writel(port, atmel_port->rtor,
					  PDC_RX_TIMEOUT);
1929
			atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_STTTO);
E
Elen Song 已提交
1930

1931 1932
			atmel_uart_writel(port, ATMEL_US_IER,
					  ATMEL_US_TIMEOUT);
1933
		}
C
Chip Coldwell 已提交
1934 1935
	} else {
		/* enable receive only */
1936
		atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_RXRDY);
C
Chip Coldwell 已提交
1937
	}
1938

1939 1940 1941
	return 0;
}

1942 1943 1944 1945 1946 1947 1948 1949 1950
/*
 * Flush any TX data submitted for DMA. Called when the TX circular
 * buffer is reset.
 */
static void atmel_flush_buffer(struct uart_port *port)
{
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

	if (atmel_use_pdc_tx(port)) {
1951
		atmel_uart_writel(port, ATMEL_PDC_TCR, 0);
1952 1953
		atmel_port->pdc_tx.ofs = 0;
	}
1954 1955 1956 1957 1958
	/*
	 * in uart_flush_buffer(), the xmit circular buffer has just
	 * been cleared, so we have to reset tx_len accordingly.
	 */
	atmel_port->tx_len = 0;
1959 1960
}

1961 1962 1963
/*
 * Disable the port
 */
1964
static void atmel_shutdown(struct uart_port *port)
1965
{
1966
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
1967

1968 1969 1970
	/* Disable modem control lines interrupts */
	atmel_disable_ms(port);

1971 1972 1973 1974 1975 1976
	/* Disable interrupts at device level */
	atmel_uart_writel(port, ATMEL_US_IDR, -1);

	/* Prevent spurious interrupts from scheduling the tasklet */
	atomic_inc(&atmel_port->tasklet_shutdown);

1977 1978 1979 1980 1981 1982
	/*
	 * Prevent any tasklets being scheduled during
	 * cleanup
	 */
	del_timer_sync(&atmel_port->uart_timer);

1983 1984 1985
	/* Make sure that no interrupt is on the fly */
	synchronize_irq(port->irq);

1986 1987 1988 1989
	/*
	 * Clear out any scheduled tasklets before
	 * we destroy the buffers
	 */
1990 1991
	tasklet_kill(&atmel_port->tasklet_rx);
	tasklet_kill(&atmel_port->tasklet_tx);
1992

C
Chip Coldwell 已提交
1993
	/*
1994
	 * Ensure everything is stopped and
1995
	 * disable port and break condition.
C
Chip Coldwell 已提交
1996 1997 1998 1999
	 */
	atmel_stop_rx(port);
	atmel_stop_tx(port);

2000
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
2001

C
Chip Coldwell 已提交
2002 2003 2004
	/*
	 * Shut-down the DMA.
	 */
2005 2006 2007 2008
	if (atmel_port->release_rx)
		atmel_port->release_rx(port);
	if (atmel_port->release_tx)
		atmel_port->release_tx(port);
C
Chip Coldwell 已提交
2009

2010 2011 2012 2013 2014 2015
	/*
	 * Reset ring buffer pointers
	 */
	atmel_port->rx_ring.head = 0;
	atmel_port->rx_ring.tail = 0;

2016
	/*
2017
	 * Free the interrupts
2018 2019
	 */
	free_irq(port->irq, port);
2020

2021
	atmel_flush_buffer(port);
2022 2023
}

2024 2025 2026
/*
 * Power / Clock management.
 */
R
Remy Bohmer 已提交
2027 2028
static void atmel_serial_pm(struct uart_port *port, unsigned int state,
			    unsigned int oldstate)
2029
{
2030
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2031

2032
	switch (state) {
R
Remy Bohmer 已提交
2033 2034 2035 2036 2037
	case 0:
		/*
		 * Enable the peripheral clock for this serial port.
		 * This is called on uart_open() or a resume event.
		 */
2038
		clk_prepare_enable(atmel_port->clk);
2039 2040

		/* re-enable interrupts if we disabled some on suspend */
2041
		atmel_uart_writel(port, ATMEL_US_IER, atmel_port->backup_imr);
R
Remy Bohmer 已提交
2042 2043
		break;
	case 3:
2044
		/* Back up the interrupt mask and disable all interrupts */
2045 2046
		atmel_port->backup_imr = atmel_uart_readl(port, ATMEL_US_IMR);
		atmel_uart_writel(port, ATMEL_US_IDR, -1);
2047

R
Remy Bohmer 已提交
2048 2049 2050 2051
		/*
		 * Disable the peripheral clock for this serial port.
		 * This is called on uart_close() or a suspend event.
		 */
2052
		clk_disable_unprepare(atmel_port->clk);
R
Remy Bohmer 已提交
2053 2054
		break;
	default:
2055
		dev_err(port->dev, "atmel_serial: unknown pm %d\n", state);
2056 2057 2058 2059 2060 2061
	}
}

/*
 * Change the port parameters
 */
R
Remy Bohmer 已提交
2062 2063
static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
			      struct ktermios *old)
2064
{
2065
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2066
	unsigned long flags;
2067
	unsigned int old_mode, mode, imr, quot, baud, div, cd, fp = 0;
2068 2069

	/* save the current mode register */
2070
	mode = old_mode = atmel_uart_readl(port, ATMEL_US_MR);
2071

2072 2073 2074
	/* reset the mode, clock divisor, parity, stop bits and data size */
	mode &= ~(ATMEL_US_USCLKS | ATMEL_US_CHRL | ATMEL_US_NBSTOP |
		  ATMEL_US_PAR | ATMEL_US_USMODE);
2075

R
Remy Bohmer 已提交
2076
	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
2077 2078 2079 2080

	/* byte size */
	switch (termios->c_cflag & CSIZE) {
	case CS5:
2081
		mode |= ATMEL_US_CHRL_5;
2082 2083
		break;
	case CS6:
2084
		mode |= ATMEL_US_CHRL_6;
2085 2086
		break;
	case CS7:
2087
		mode |= ATMEL_US_CHRL_7;
2088 2089
		break;
	default:
2090
		mode |= ATMEL_US_CHRL_8;
2091 2092 2093 2094 2095
		break;
	}

	/* stop bits */
	if (termios->c_cflag & CSTOPB)
2096
		mode |= ATMEL_US_NBSTOP_2;
2097 2098 2099

	/* parity */
	if (termios->c_cflag & PARENB) {
R
Remy Bohmer 已提交
2100 2101
		/* Mark or Space parity */
		if (termios->c_cflag & CMSPAR) {
2102
			if (termios->c_cflag & PARODD)
2103
				mode |= ATMEL_US_PAR_MARK;
2104
			else
2105
				mode |= ATMEL_US_PAR_SPACE;
R
Remy Bohmer 已提交
2106
		} else if (termios->c_cflag & PARODD)
2107
			mode |= ATMEL_US_PAR_ODD;
2108
		else
2109
			mode |= ATMEL_US_PAR_EVEN;
R
Remy Bohmer 已提交
2110
	} else
2111
		mode |= ATMEL_US_PAR_NONE;
2112 2113 2114

	spin_lock_irqsave(&port->lock, flags);

2115
	port->read_status_mask = ATMEL_US_OVRE;
2116
	if (termios->c_iflag & INPCK)
2117
		port->read_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
P
Peter Hurley 已提交
2118
	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
2119
		port->read_status_mask |= ATMEL_US_RXBRK;
2120

2121
	if (atmel_use_pdc_rx(port))
C
Chip Coldwell 已提交
2122
		/* need to enable error interrupts */
2123
		atmel_uart_writel(port, ATMEL_US_IER, port->read_status_mask);
C
Chip Coldwell 已提交
2124

2125 2126 2127 2128 2129
	/*
	 * Characters to ignore
	 */
	port->ignore_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
2130
		port->ignore_status_mask |= (ATMEL_US_FRAME | ATMEL_US_PARE);
2131
	if (termios->c_iflag & IGNBRK) {
2132
		port->ignore_status_mask |= ATMEL_US_RXBRK;
2133 2134 2135 2136 2137
		/*
		 * If we're ignoring parity and break indicators,
		 * ignore overruns too (for real raw support).
		 */
		if (termios->c_iflag & IGNPAR)
2138
			port->ignore_status_mask |= ATMEL_US_OVRE;
2139
	}
R
Remy Bohmer 已提交
2140
	/* TODO: Ignore all characters if CREAD is set.*/
2141 2142 2143 2144

	/* update the per-port timeout */
	uart_update_timeout(port, termios->c_cflag, baud);

2145 2146 2147 2148 2149
	/*
	 * save/disable interrupts. The tty layer will ensure that the
	 * transmitter is empty if requested by the caller, so there's
	 * no need to wait for it here.
	 */
2150 2151
	imr = atmel_uart_readl(port, ATMEL_US_IMR);
	atmel_uart_writel(port, ATMEL_US_IDR, -1);
2152 2153

	/* disable receiver and transmitter */
2154
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
2155

2156
	/* mode */
2157
	if (port->rs485.flags & SER_RS485_ENABLED) {
2158 2159
		atmel_uart_writel(port, ATMEL_US_TTGR,
				  port->rs485.delay_rts_after_send);
2160
		mode |= ATMEL_US_USMODE_RS485;
2161 2162
	} else if (termios->c_cflag & CRTSCTS) {
		/* RS232 with hardware handshake (RTS/CTS) */
2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178
		if (atmel_use_fifo(port) &&
		    !mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) {
			/*
			 * with ATMEL_US_USMODE_HWHS set, the controller will
			 * be able to drive the RTS pin high/low when the RX
			 * FIFO is above RXFTHRES/below RXFTHRES2.
			 * It will also disable the transmitter when the CTS
			 * pin is high.
			 * This mode is not activated if CTS pin is a GPIO
			 * because in this case, the transmitter is always
			 * disabled (there must be an internal pull-up
			 * responsible for this behaviour).
			 * If the RTS pin is a GPIO, the controller won't be
			 * able to drive it according to the FIFO thresholds,
			 * but it will be handled by the driver.
			 */
2179
			mode |= ATMEL_US_USMODE_HWHS;
2180 2181 2182 2183 2184 2185
		} else {
			/*
			 * For platforms without FIFO, the flow control is
			 * handled by the driver.
			 */
			mode |= ATMEL_US_USMODE_NORMAL;
2186
		}
2187 2188 2189
	} else {
		/* RS232 without hadware handshake */
		mode |= ATMEL_US_USMODE_NORMAL;
2190 2191
	}

2192
	/* set the mode, clock divisor, parity, stop bits and data size */
2193
	atmel_uart_writel(port, ATMEL_US_MR, mode);
2194

2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209
	/*
	 * when switching the mode, set the RTS line state according to the
	 * new mode, otherwise keep the former state
	 */
	if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
		unsigned int rts_state;

		if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
			/* let the hardware control the RTS line */
			rts_state = ATMEL_US_RTSDIS;
		} else {
			/* force RTS line to low level */
			rts_state = ATMEL_US_RTSEN;
		}

2210
		atmel_uart_writel(port, ATMEL_US_CR, rts_state);
2211 2212
	}

2213 2214 2215 2216 2217 2218
	/*
	 * Set the baud rate:
	 * Fractional baudrate allows to setup output frequency more
	 * accurately. This feature is enabled only when using normal mode.
	 * baudrate = selected clock / (8 * (2 - OVER) * (CD + FP / 8))
	 * Currently, OVER is always set to 0 so we get
2219 2220 2221
	 * baudrate = selected clock / (16 * (CD + FP / 8))
	 * then
	 * 8 CD + FP = selected clock / (2 * baudrate)
2222
	 */
2223
	if (atmel_port->has_frac_baudrate) {
2224 2225 2226
		div = DIV_ROUND_CLOSEST(port->uartclk, baud * 2);
		cd = div >> 3;
		fp = div & ATMEL_US_FP_MASK;
2227 2228 2229 2230 2231 2232 2233 2234 2235 2236
	} else {
		cd = uart_get_divisor(port, baud);
	}

	if (cd > 65535) {	/* BRGR is 16-bit, so switch to slower clock */
		cd /= 8;
		mode |= ATMEL_US_USCLKS_MCK_DIV8;
	}
	quot = cd | fp << ATMEL_US_FP_OFFSET;

2237 2238 2239
	atmel_uart_writel(port, ATMEL_US_BRGR, quot);
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
2240 2241

	/* restore interrupts */
2242
	atmel_uart_writel(port, ATMEL_US_IER, imr);
2243 2244 2245

	/* CTS flow-control and modem-status interrupts */
	if (UART_ENABLE_MS(port, termios->c_cflag))
2246 2247 2248
		atmel_enable_ms(port);
	else
		atmel_disable_ms(port);
2249 2250 2251 2252

	spin_unlock_irqrestore(&port->lock, flags);
}

2253
static void atmel_set_ldisc(struct uart_port *port, struct ktermios *termios)
2254
{
2255
	if (termios->c_line == N_PPS) {
2256
		port->flags |= UPF_HARDPPS_CD;
2257
		spin_lock_irq(&port->lock);
2258
		atmel_enable_ms(port);
2259
		spin_unlock_irq(&port->lock);
2260 2261
	} else {
		port->flags &= ~UPF_HARDPPS_CD;
2262 2263 2264 2265 2266
		if (!UART_ENABLE_MS(port, termios->c_cflag)) {
			spin_lock_irq(&port->lock);
			atmel_disable_ms(port);
			spin_unlock_irq(&port->lock);
		}
2267 2268 2269
	}
}

2270 2271 2272
/*
 * Return string describing the specified port
 */
2273
static const char *atmel_type(struct uart_port *port)
2274
{
2275
	return (port->type == PORT_ATMEL) ? "ATMEL_SERIAL" : NULL;
2276 2277 2278 2279 2280
}

/*
 * Release the memory region(s) being used by 'port'.
 */
2281
static void atmel_release_port(struct uart_port *port)
2282
{
2283 2284 2285 2286 2287 2288 2289 2290 2291
	struct platform_device *pdev = to_platform_device(port->dev);
	int size = pdev->resource[0].end - pdev->resource[0].start + 1;

	release_mem_region(port->mapbase, size);

	if (port->flags & UPF_IOREMAP) {
		iounmap(port->membase);
		port->membase = NULL;
	}
2292 2293 2294 2295 2296
}

/*
 * Request the memory region(s) being used by 'port'.
 */
2297
static int atmel_request_port(struct uart_port *port)
2298
{
2299 2300 2301
	struct platform_device *pdev = to_platform_device(port->dev);
	int size = pdev->resource[0].end - pdev->resource[0].start + 1;

2302
	if (!request_mem_region(port->mapbase, size, "atmel_serial"))
2303 2304 2305 2306 2307 2308 2309 2310 2311
		return -EBUSY;

	if (port->flags & UPF_IOREMAP) {
		port->membase = ioremap(port->mapbase, size);
		if (port->membase == NULL) {
			release_mem_region(port->mapbase, size);
			return -ENOMEM;
		}
	}
2312

2313
	return 0;
2314 2315 2316 2317 2318
}

/*
 * Configure/autoconfigure the port.
 */
2319
static void atmel_config_port(struct uart_port *port, int flags)
2320 2321
{
	if (flags & UART_CONFIG_TYPE) {
2322
		port->type = PORT_ATMEL;
2323
		atmel_request_port(port);
2324 2325 2326 2327 2328 2329
	}
}

/*
 * Verify the new serial_struct (for TIOCSSERIAL).
 */
2330
static int atmel_verify_port(struct uart_port *port, struct serial_struct *ser)
2331 2332
{
	int ret = 0;
2333
	if (ser->type != PORT_UNKNOWN && ser->type != PORT_ATMEL)
2334 2335 2336 2337 2338 2339 2340
		ret = -EINVAL;
	if (port->irq != ser->irq)
		ret = -EINVAL;
	if (ser->io_type != SERIAL_IO_MEM)
		ret = -EINVAL;
	if (port->uartclk / 16 != ser->baud_base)
		ret = -EINVAL;
2341
	if (port->mapbase != (unsigned long)ser->iomem_base)
2342 2343 2344 2345 2346 2347 2348 2349
		ret = -EINVAL;
	if (port->iobase != ser->port)
		ret = -EINVAL;
	if (ser->hub6 != 0)
		ret = -EINVAL;
	return ret;
}

2350 2351 2352
#ifdef CONFIG_CONSOLE_POLL
static int atmel_poll_get_char(struct uart_port *port)
{
2353
	while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_RXRDY))
2354 2355
		cpu_relax();

2356
	return atmel_uart_read_char(port);
2357 2358 2359 2360
}

static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
{
2361
	while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
2362 2363
		cpu_relax();

2364
	atmel_uart_write_char(port, ch);
2365 2366 2367
}
#endif

2368
static const struct uart_ops atmel_pops = {
2369 2370 2371 2372 2373 2374 2375 2376 2377 2378
	.tx_empty	= atmel_tx_empty,
	.set_mctrl	= atmel_set_mctrl,
	.get_mctrl	= atmel_get_mctrl,
	.stop_tx	= atmel_stop_tx,
	.start_tx	= atmel_start_tx,
	.stop_rx	= atmel_stop_rx,
	.enable_ms	= atmel_enable_ms,
	.break_ctl	= atmel_break_ctl,
	.startup	= atmel_startup,
	.shutdown	= atmel_shutdown,
2379
	.flush_buffer	= atmel_flush_buffer,
2380
	.set_termios	= atmel_set_termios,
2381
	.set_ldisc	= atmel_set_ldisc,
2382 2383 2384 2385 2386 2387
	.type		= atmel_type,
	.release_port	= atmel_release_port,
	.request_port	= atmel_request_port,
	.config_port	= atmel_config_port,
	.verify_port	= atmel_verify_port,
	.pm		= atmel_serial_pm,
2388 2389 2390 2391
#ifdef CONFIG_CONSOLE_POLL
	.poll_get_char	= atmel_poll_get_char,
	.poll_put_char	= atmel_poll_put_char,
#endif
2392 2393
};

2394 2395 2396
/*
 * Configure the port from the platform device resource info.
 */
2397
static int atmel_init_port(struct atmel_uart_port *atmel_port,
R
Remy Bohmer 已提交
2398
				      struct platform_device *pdev)
2399
{
2400
	int ret;
2401
	struct uart_port *port = &atmel_port->uart;
J
Jingoo Han 已提交
2402
	struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev);
2403

2404 2405
	atmel_init_property(atmel_port, pdev);
	atmel_set_ops(port);
2406

2407
	atmel_init_rs485(port, pdev);
2408

2409 2410 2411 2412 2413
	port->iotype		= UPIO_MEM;
	port->flags		= UPF_BOOT_AUTOCONF;
	port->ops		= &atmel_pops;
	port->fifosize		= 1;
	port->dev		= &pdev->dev;
2414 2415
	port->mapbase	= pdev->resource[0].start;
	port->irq	= pdev->resource[1].start;
2416
	port->rs485_config	= atmel_config_rs485;
2417

2418 2419
	memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));

2420
	if (pdata && pdata->regs) {
2421
		/* Already mapped by setup code */
2422
		port->membase = pdata->regs;
2423
	} else {
2424 2425 2426
		port->flags	|= UPF_IOREMAP;
		port->membase	= NULL;
	}
2427

R
Remy Bohmer 已提交
2428 2429
	/* for console, the clock could already be configured */
	if (!atmel_port->clk) {
2430
		atmel_port->clk = clk_get(&pdev->dev, "usart");
2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441
		if (IS_ERR(atmel_port->clk)) {
			ret = PTR_ERR(atmel_port->clk);
			atmel_port->clk = NULL;
			return ret;
		}
		ret = clk_prepare_enable(atmel_port->clk);
		if (ret) {
			clk_put(atmel_port->clk);
			atmel_port->clk = NULL;
			return ret;
		}
2442
		port->uartclk = clk_get_rate(atmel_port->clk);
2443
		clk_disable_unprepare(atmel_port->clk);
2444
		/* only enable clock when USART is in use */
2445
	}
C
Chip Coldwell 已提交
2446

2447
	/* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */
2448
	if (port->rs485.flags & SER_RS485_ENABLED)
2449
		atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
2450
	else if (atmel_use_pdc_tx(port)) {
C
Chip Coldwell 已提交
2451
		port->fifosize = PDC_BUFFER_SIZE;
2452 2453 2454 2455
		atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE;
	} else {
		atmel_port->tx_done_mask = ATMEL_US_TXRDY;
	}
2456 2457

	return 0;
2458 2459
}

2460 2461
struct platform_device *atmel_default_console_device;	/* the serial console device */

2462
#ifdef CONFIG_SERIAL_ATMEL_CONSOLE
2463
static void atmel_console_putchar(struct uart_port *port, int ch)
2464
{
2465
	while (!(atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY))
2466
		cpu_relax();
2467
	atmel_uart_write_char(port, ch);
2468
}
2469 2470 2471 2472

/*
 * Interrupts are disabled on entering
 */
2473
static void atmel_console_write(struct console *co, const char *s, u_int count)
2474
{
2475
	struct uart_port *port = &atmel_ports[co->index].uart;
2476
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2477
	unsigned int status, imr;
2478
	unsigned int pdc_tx;
2479 2480

	/*
R
Remy Bohmer 已提交
2481
	 * First, save IMR and then disable interrupts
2482
	 */
2483 2484 2485
	imr = atmel_uart_readl(port, ATMEL_US_IMR);
	atmel_uart_writel(port, ATMEL_US_IDR,
			  ATMEL_US_RXRDY | atmel_port->tx_done_mask);
2486

2487
	/* Store PDC transmit status and disable it */
2488 2489
	pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN;
	atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
2490

2491 2492 2493
	/* Make sure that tx path is actually able to send characters */
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);

2494
	uart_console_write(port, s, count, atmel_console_putchar);
2495 2496

	/*
R
Remy Bohmer 已提交
2497 2498
	 * Finally, wait for transmitter to become empty
	 * and restore IMR
2499 2500
	 */
	do {
2501
		status = atmel_uart_readl(port, ATMEL_US_CSR);
2502
	} while (!(status & ATMEL_US_TXRDY));
2503 2504 2505

	/* Restore PDC transmit status */
	if (pdc_tx)
2506
		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
2507

R
Remy Bohmer 已提交
2508
	/* set interrupts back the way they were */
2509
	atmel_uart_writel(port, ATMEL_US_IER, imr);
2510 2511 2512
}

/*
R
Remy Bohmer 已提交
2513 2514
 * If the port was already initialised (eg, by a boot loader),
 * try to determine the current setup.
2515
 */
R
Remy Bohmer 已提交
2516 2517
static void __init atmel_console_get_options(struct uart_port *port, int *baud,
					     int *parity, int *bits)
2518 2519 2520
{
	unsigned int mr, quot;

2521 2522 2523 2524
	/*
	 * If the baud rate generator isn't running, the port wasn't
	 * initialized by the boot loader.
	 */
2525
	quot = atmel_uart_readl(port, ATMEL_US_BRGR) & ATMEL_US_CD;
2526 2527
	if (!quot)
		return;
2528

2529
	mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_CHRL;
2530
	if (mr == ATMEL_US_CHRL_8)
2531 2532 2533 2534
		*bits = 8;
	else
		*bits = 7;

2535
	mr = atmel_uart_readl(port, ATMEL_US_MR) & ATMEL_US_PAR;
2536
	if (mr == ATMEL_US_PAR_EVEN)
2537
		*parity = 'e';
2538
	else if (mr == ATMEL_US_PAR_ODD)
2539 2540
		*parity = 'o';

2541 2542 2543 2544 2545 2546 2547
	/*
	 * The serial core only rounds down when matching this to a
	 * supported baud rate. Make sure we don't end up slightly
	 * lower than one of those, as it would make us fall through
	 * to a much lower baud rate than we really want.
	 */
	*baud = port->uartclk / (16 * (quot - 1));
2548 2549
}

2550
static int __init atmel_console_setup(struct console *co, char *options)
2551
{
2552
	int ret;
2553
	struct uart_port *port = &atmel_ports[co->index].uart;
2554 2555 2556 2557 2558
	int baud = 115200;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

R
Remy Bohmer 已提交
2559 2560
	if (port->membase == NULL) {
		/* Port not initialized yet - delay setup */
2561
		return -ENODEV;
R
Remy Bohmer 已提交
2562
	}
2563

2564 2565 2566
	ret = clk_prepare_enable(atmel_ports[co->index].clk);
	if (ret)
		return ret;
2567

2568 2569 2570
	atmel_uart_writel(port, ATMEL_US_IDR, -1);
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
2571 2572 2573 2574

	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);
	else
2575
		atmel_console_get_options(port, &baud, &parity, &bits);
2576 2577 2578 2579

	return uart_set_options(port, co, baud, parity, bits, flow);
}

2580
static struct uart_driver atmel_uart;
2581

2582 2583 2584
static struct console atmel_console = {
	.name		= ATMEL_DEVICENAME,
	.write		= atmel_console_write,
2585
	.device		= uart_console_device,
2586
	.setup		= atmel_console_setup,
2587 2588
	.flags		= CON_PRINTBUFFER,
	.index		= -1,
2589
	.data		= &atmel_uart,
2590 2591
};

2592
#define ATMEL_CONSOLE_DEVICE	(&atmel_console)
2593

2594 2595 2596
/*
 * Early console initialization (before VM subsystem initialized).
 */
2597
static int __init atmel_console_init(void)
2598
{
2599
	int ret;
2600
	if (atmel_default_console_device) {
2601
		struct atmel_uart_data *pdata =
J
Jingoo Han 已提交
2602
			dev_get_platdata(&atmel_default_console_device->dev);
2603
		int id = pdata->num;
2604
		struct atmel_uart_port *atmel_port = &atmel_ports[id];
2605

2606 2607
		atmel_port->backup_imr = 0;
		atmel_port->uart.line = id;
2608

2609
		add_preferred_console(ATMEL_DEVICENAME, id, NULL);
2610
		ret = atmel_init_port(atmel_port, atmel_default_console_device);
2611 2612
		if (ret)
			return ret;
2613
		register_console(&atmel_console);
2614
	}
2615 2616 2617

	return 0;
}
R
Remy Bohmer 已提交
2618

2619
console_initcall(atmel_console_init);
2620

2621 2622 2623
/*
 * Late console initialization.
 */
2624
static int __init atmel_late_console_init(void)
2625
{
R
Remy Bohmer 已提交
2626 2627
	if (atmel_default_console_device
	    && !(atmel_console.flags & CON_ENABLED))
2628
		register_console(&atmel_console);
2629 2630 2631

	return 0;
}
R
Remy Bohmer 已提交
2632

2633
core_initcall(atmel_late_console_init);
2634

2635 2636 2637 2638 2639
static inline bool atmel_is_console_port(struct uart_port *port)
{
	return port->cons && port->cons->index == port->line;
}

2640
#else
2641
#define ATMEL_CONSOLE_DEVICE	NULL
2642 2643 2644 2645 2646

static inline bool atmel_is_console_port(struct uart_port *port)
{
	return false;
}
2647 2648
#endif

2649
static struct uart_driver atmel_uart = {
R
Remy Bohmer 已提交
2650 2651 2652 2653 2654 2655 2656
	.owner		= THIS_MODULE,
	.driver_name	= "atmel_serial",
	.dev_name	= ATMEL_DEVICENAME,
	.major		= SERIAL_ATMEL_MAJOR,
	.minor		= MINOR_START,
	.nr		= ATMEL_MAX_UART,
	.cons		= ATMEL_CONSOLE_DEVICE,
2657 2658
};

2659
#ifdef CONFIG_PM
2660 2661 2662 2663 2664 2665 2666 2667 2668
static bool atmel_serial_clk_will_stop(void)
{
#ifdef CONFIG_ARCH_AT91
	return at91_suspend_entering_slow_clock();
#else
	return false;
#endif
}

R
Remy Bohmer 已提交
2669 2670
static int atmel_serial_suspend(struct platform_device *pdev,
				pm_message_t state)
2671
{
2672
	struct uart_port *port = platform_get_drvdata(pdev);
2673
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2674

2675 2676
	if (atmel_is_console_port(port) && console_suspend_enabled) {
		/* Drain the TX shifter */
2677 2678
		while (!(atmel_uart_readl(port, ATMEL_US_CSR) &
			 ATMEL_US_TXEMPTY))
2679 2680 2681
			cpu_relax();
	}

2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695
	if (atmel_is_console_port(port) && !console_suspend_enabled) {
		/* Cache register values as we won't get a full shutdown/startup
		 * cycle
		 */
		atmel_port->cache.mr = atmel_uart_readl(port, ATMEL_US_MR);
		atmel_port->cache.imr = atmel_uart_readl(port, ATMEL_US_IMR);
		atmel_port->cache.brgr = atmel_uart_readl(port, ATMEL_US_BRGR);
		atmel_port->cache.rtor = atmel_uart_readl(port,
							  atmel_port->rtor);
		atmel_port->cache.ttgr = atmel_uart_readl(port, ATMEL_US_TTGR);
		atmel_port->cache.fmr = atmel_uart_readl(port, ATMEL_US_FMR);
		atmel_port->cache.fimr = atmel_uart_readl(port, ATMEL_US_FIMR);
	}

2696 2697
	/* we can not wake up if we're running on slow clock */
	atmel_port->may_wakeup = device_may_wakeup(&pdev->dev);
2698 2699 2700 2701 2702 2703
	if (atmel_serial_clk_will_stop()) {
		unsigned long flags;

		spin_lock_irqsave(&atmel_port->lock_suspended, flags);
		atmel_port->suspended = true;
		spin_unlock_irqrestore(&atmel_port->lock_suspended, flags);
2704
		device_set_wakeup_enable(&pdev->dev, 0);
2705
	}
2706 2707

	uart_suspend_port(&atmel_uart, port);
2708

2709 2710
	return 0;
}
2711

2712
static int atmel_serial_resume(struct platform_device *pdev)
2713 2714
{
	struct uart_port *port = platform_get_drvdata(pdev);
2715
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
2716 2717
	unsigned long flags;

2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736
	if (atmel_is_console_port(port) && !console_suspend_enabled) {
		atmel_uart_writel(port, ATMEL_US_MR, atmel_port->cache.mr);
		atmel_uart_writel(port, ATMEL_US_IER, atmel_port->cache.imr);
		atmel_uart_writel(port, ATMEL_US_BRGR, atmel_port->cache.brgr);
		atmel_uart_writel(port, atmel_port->rtor,
				  atmel_port->cache.rtor);
		atmel_uart_writel(port, ATMEL_US_TTGR, atmel_port->cache.ttgr);

		if (atmel_port->fifo_size) {
			atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_FIFOEN |
					  ATMEL_US_RXFCLR | ATMEL_US_TXFLCLR);
			atmel_uart_writel(port, ATMEL_US_FMR,
					  atmel_port->cache.fmr);
			atmel_uart_writel(port, ATMEL_US_FIER,
					  atmel_port->cache.fimr);
		}
		atmel_start_rx(port);
	}

2737 2738 2739 2740 2741 2742 2743 2744 2745 2746
	spin_lock_irqsave(&atmel_port->lock_suspended, flags);
	if (atmel_port->pending) {
		atmel_handle_receive(port, atmel_port->pending);
		atmel_handle_status(port, atmel_port->pending,
				    atmel_port->pending_status);
		atmel_handle_transmit(port, atmel_port->pending);
		atmel_port->pending = 0;
	}
	atmel_port->suspended = false;
	spin_unlock_irqrestore(&atmel_port->lock_suspended, flags);
2747

2748 2749
	uart_resume_port(&atmel_uart, port);
	device_set_wakeup_enable(&pdev->dev, atmel_port->may_wakeup);
2750 2751 2752

	return 0;
}
2753
#else
2754 2755
#define atmel_serial_suspend NULL
#define atmel_serial_resume NULL
2756
#endif
2757

2758
static void atmel_serial_probe_fifos(struct atmel_uart_port *atmel_port,
2759 2760
				     struct platform_device *pdev)
{
2761 2762 2763
	atmel_port->fifo_size = 0;
	atmel_port->rts_low = 0;
	atmel_port->rts_high = 0;
2764 2765 2766

	if (of_property_read_u32(pdev->dev.of_node,
				 "atmel,fifo-size",
2767
				 &atmel_port->fifo_size))
2768 2769
		return;

2770
	if (!atmel_port->fifo_size)
2771 2772
		return;

2773 2774
	if (atmel_port->fifo_size < ATMEL_MIN_FIFO_SIZE) {
		atmel_port->fifo_size = 0;
2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786
		dev_err(&pdev->dev, "Invalid FIFO size\n");
		return;
	}

	/*
	 * 0 <= rts_low <= rts_high <= fifo_size
	 * Once their CTS line asserted by the remote peer, some x86 UARTs tend
	 * to flush their internal TX FIFO, commonly up to 16 data, before
	 * actually stopping to send new data. So we try to set the RTS High
	 * Threshold to a reasonably high value respecting this 16 data
	 * empirical rule when possible.
	 */
2787 2788 2789 2790
	atmel_port->rts_high = max_t(int, atmel_port->fifo_size >> 1,
			       atmel_port->fifo_size - ATMEL_RTS_HIGH_OFFSET);
	atmel_port->rts_low  = max_t(int, atmel_port->fifo_size >> 2,
			       atmel_port->fifo_size - ATMEL_RTS_LOW_OFFSET);
2791 2792

	dev_info(&pdev->dev, "Using FIFO (%u data)\n",
2793
		 atmel_port->fifo_size);
2794
	dev_dbg(&pdev->dev, "RTS High Threshold : %2u data\n",
2795
		atmel_port->rts_high);
2796
	dev_dbg(&pdev->dev, "RTS Low Threshold  : %2u data\n",
2797
		atmel_port->rts_low);
2798 2799
}

B
Bill Pemberton 已提交
2800
static int atmel_serial_probe(struct platform_device *pdev)
2801
{
2802
	struct atmel_uart_port *atmel_port;
2803
	struct device_node *np = pdev->dev.of_node;
J
Jingoo Han 已提交
2804
	struct atmel_uart_data *pdata = dev_get_platdata(&pdev->dev);
2805
	void *data;
2806
	int ret = -ENODEV;
2807
	bool rs485_enabled;
2808

2809
	BUILD_BUG_ON(ATMEL_SERIAL_RINGSIZE & (ATMEL_SERIAL_RINGSIZE - 1));
2810

2811 2812 2813 2814 2815
	if (np)
		ret = of_alias_get_id(np, "serial");
	else
		if (pdata)
			ret = pdata->num;
2816 2817

	if (ret < 0)
2818
		/* port id not found in platform data nor device-tree aliases:
2819
		 * auto-enumerate it */
2820
		ret = find_first_zero_bit(atmel_ports_in_use, ATMEL_MAX_UART);
2821

2822
	if (ret >= ATMEL_MAX_UART) {
2823 2824 2825 2826
		ret = -ENODEV;
		goto err;
	}

2827
	if (test_and_set_bit(ret, atmel_ports_in_use)) {
2828 2829 2830 2831 2832
		/* port already in use */
		ret = -EBUSY;
		goto err;
	}

2833 2834 2835 2836
	atmel_port = &atmel_ports[ret];
	atmel_port->backup_imr = 0;
	atmel_port->uart.line = ret;
	atmel_serial_probe_fifos(atmel_port, pdev);
2837

2838
	atomic_set(&atmel_port->tasklet_shutdown, 0);
2839
	spin_lock_init(&atmel_port->lock_suspended);
2840

2841
	ret = atmel_init_port(atmel_port, pdev);
2842
	if (ret)
2843
		goto err_clear_bit;
2844

2845 2846 2847
	atmel_port->gpios = mctrl_gpio_init(&atmel_port->uart, 0);
	if (IS_ERR(atmel_port->gpios)) {
		ret = PTR_ERR(atmel_port->gpios);
2848 2849 2850
		goto err_clear_bit;
	}

2851
	if (!atmel_use_pdc_rx(&atmel_port->uart)) {
C
Chip Coldwell 已提交
2852
		ret = -ENOMEM;
2853 2854
		data = kmalloc(sizeof(struct atmel_uart_char)
				* ATMEL_SERIAL_RINGSIZE, GFP_KERNEL);
C
Chip Coldwell 已提交
2855 2856
		if (!data)
			goto err_alloc_ring;
2857
		atmel_port->rx_ring.buf = data;
C
Chip Coldwell 已提交
2858
	}
2859

2860
	rs485_enabled = atmel_port->uart.rs485.flags & SER_RS485_ENABLED;
2861

2862
	ret = uart_add_one_port(&atmel_uart, &atmel_port->uart);
2863 2864 2865
	if (ret)
		goto err_add_port;

2866
#ifdef CONFIG_SERIAL_ATMEL_CONSOLE
2867
	if (atmel_is_console_port(&atmel_port->uart)
2868 2869 2870
			&& ATMEL_CONSOLE_DEVICE->flags & CON_ENABLED) {
		/*
		 * The serial core enabled the clock for us, so undo
2871
		 * the clk_prepare_enable() in atmel_console_setup()
2872
		 */
2873
		clk_disable_unprepare(atmel_port->clk);
2874
	}
2875
#endif
2876

2877
	device_init_wakeup(&pdev->dev, 1);
2878
	platform_set_drvdata(pdev, atmel_port);
2879

2880 2881 2882 2883
	/*
	 * The peripheral clock has been disabled by atmel_init_port():
	 * enable it before accessing I/O registers
	 */
2884
	clk_prepare_enable(atmel_port->clk);
2885

2886
	if (rs485_enabled) {
2887
		atmel_uart_writel(&atmel_port->uart, ATMEL_US_MR,
2888
				  ATMEL_US_USMODE_NORMAL);
2889 2890
		atmel_uart_writel(&atmel_port->uart, ATMEL_US_CR,
				  ATMEL_US_RTSEN);
2891 2892
	}

2893 2894 2895
	/*
	 * Get port name of usart or uart
	 */
2896
	atmel_get_ip_name(&atmel_port->uart);
2897

2898 2899 2900 2901
	/*
	 * The peripheral clock can now safely be disabled till the port
	 * is used
	 */
2902
	clk_disable_unprepare(atmel_port->clk);
2903

2904 2905 2906
	return 0;

err_add_port:
2907 2908
	kfree(atmel_port->rx_ring.buf);
	atmel_port->rx_ring.buf = NULL;
2909
err_alloc_ring:
2910 2911 2912
	if (!atmel_is_console_port(&atmel_port->uart)) {
		clk_put(atmel_port->clk);
		atmel_port->clk = NULL;
2913
	}
2914
err_clear_bit:
2915
	clear_bit(atmel_port->uart.line, atmel_ports_in_use);
2916
err:
2917 2918 2919
	return ret;
}

2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934
/*
 * Even if the driver is not modular, it makes sense to be able to
 * unbind a device: there can be many bound devices, and there are
 * situations where dynamic binding and unbinding can be useful.
 *
 * For example, a connected device can require a specific firmware update
 * protocol that needs bitbanging on IO lines, but use the regular serial
 * port in the normal case.
 */
static int atmel_serial_remove(struct platform_device *pdev)
{
	struct uart_port *port = platform_get_drvdata(pdev);
	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
	int ret = 0;

2935 2936
	tasklet_kill(&atmel_port->tasklet_rx);
	tasklet_kill(&atmel_port->tasklet_tx);
2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953

	device_init_wakeup(&pdev->dev, 0);

	ret = uart_remove_one_port(&atmel_uart, port);

	kfree(atmel_port->rx_ring.buf);

	/* "port" is allocated statically, so we shouldn't free it */

	clear_bit(port->line, atmel_ports_in_use);

	clk_put(atmel_port->clk);
	atmel_port->clk = NULL;

	return ret;
}

2954 2955
static struct platform_driver atmel_serial_driver = {
	.probe		= atmel_serial_probe,
2956
	.remove		= atmel_serial_remove,
2957 2958
	.suspend	= atmel_serial_suspend,
	.resume		= atmel_serial_resume,
2959
	.driver		= {
2960 2961
		.name			= "atmel_usart",
		.of_match_table		= of_match_ptr(atmel_serial_dt_ids),
2962 2963 2964
	},
};

2965
static int __init atmel_serial_init(void)
2966 2967 2968
{
	int ret;

2969
	ret = uart_register_driver(&atmel_uart);
2970 2971 2972
	if (ret)
		return ret;

2973
	ret = platform_driver_register(&atmel_serial_driver);
2974
	if (ret)
2975
		uart_unregister_driver(&atmel_uart);
2976 2977 2978

	return ret;
}
2979
device_initcall(atmel_serial_init);