vt8500_serial.c 15.6 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546
/*
 * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
 *
 * Based on msm_serial.c, which is:
 * Copyright (C) 2007 Google, Inc.
 * Author: Robert Love <rlove@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
# define SUPPORT_SYSRQ
#endif

#include <linux/hrtimer.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/platform_device.h>

/*
 * UART Register offsets
 */

#define VT8500_URTDR		0x0000	/* Transmit data */
#define VT8500_URRDR		0x0004	/* Receive data */
#define VT8500_URDIV		0x0008	/* Clock/Baud rate divisor */
#define VT8500_URLCR		0x000C	/* Line control */
#define VT8500_URICR		0x0010	/* IrDA control */
#define VT8500_URIER		0x0014	/* Interrupt enable */
#define VT8500_URISR		0x0018	/* Interrupt status */
#define VT8500_URUSR		0x001c	/* UART status */
#define VT8500_URFCR		0x0020	/* FIFO control */
#define VT8500_URFIDX		0x0024	/* FIFO index */
#define VT8500_URBKR		0x0028	/* Break signal count */
#define VT8500_URTOD		0x002c	/* Time out divisor */
#define VT8500_TXFIFO		0x1000	/* Transmit FIFO (16x8) */
#define VT8500_RXFIFO		0x1020	/* Receive FIFO (16x10) */

/*
 * Interrupt enable and status bits
 */

#define TXDE	(1 << 0)	/* Tx Data empty */
#define RXDF	(1 << 1)	/* Rx Data full */
#define TXFAE	(1 << 2)	/* Tx FIFO almost empty */
#define TXFE	(1 << 3)	/* Tx FIFO empty */
#define RXFAF	(1 << 4)	/* Rx FIFO almost full */
#define RXFF	(1 << 5)	/* Rx FIFO full */
#define TXUDR	(1 << 6)	/* Tx underrun */
#define RXOVER	(1 << 7)	/* Rx overrun */
#define PER	(1 << 8)	/* Parity error */
#define FER	(1 << 9)	/* Frame error */
#define TCTS	(1 << 10)	/* Toggle of CTS */
#define RXTOUT	(1 << 11)	/* Rx timeout */
#define BKDONE	(1 << 12)	/* Break signal done */
#define ERR	(1 << 13)	/* AHB error response */

#define RX_FIFO_INTS	(RXFAF | RXFF | RXOVER | PER | FER | RXTOUT)
#define TX_FIFO_INTS	(TXFAE | TXFE | TXUDR)

struct vt8500_port {
	struct uart_port	uart;
	char			name[16];
	struct clk		*clk;
	unsigned int		ier;
};

static inline void vt8500_write(struct uart_port *port, unsigned int val,
			     unsigned int off)
{
	writel(val, port->membase + off);
}

static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off)
{
	return readl(port->membase + off);
}

static void vt8500_stop_tx(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier &= ~TX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void vt8500_stop_rx(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier &= ~RX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void vt8500_enable_ms(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier |= TCTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void handle_rx(struct uart_port *port)
{
	struct tty_struct *tty = tty_port_tty_get(&port->state->port);
	if (!tty) {
		/* Discard data: no tty available */
		int count = (vt8500_read(port, VT8500_URFIDX) & 0x1f00) >> 8;
		u16 ch;
		while (count--)
			ch = readw(port->membase + VT8500_RXFIFO);
		return;
	}

	/*
	 * Handle overrun
	 */
	if ((vt8500_read(port, VT8500_URISR) & RXOVER)) {
		port->icount.overrun++;
		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
	}

	/* and now the main RX loop */
	while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) {
		unsigned int c;
		char flag = TTY_NORMAL;

		c = readw(port->membase + VT8500_RXFIFO) & 0x3ff;

		/* Mask conditions we're ignorning. */
		c &= ~port->read_status_mask;

		if (c & FER) {
			port->icount.frame++;
			flag = TTY_FRAME;
		} else if (c & PER) {
			port->icount.parity++;
			flag = TTY_PARITY;
		}
		port->icount.rx++;

		if (!uart_handle_sysrq_char(port, c))
			tty_insert_flip_char(tty, c, flag);
	}

	tty_flip_buffer_push(tty);
	tty_kref_put(tty);
}

static void handle_tx(struct uart_port *port)
{
	struct circ_buf *xmit = &port->state->xmit;

	if (port->x_char) {
		writeb(port->x_char, port->membase + VT8500_TXFIFO);
		port->icount.tx++;
		port->x_char = 0;
	}
	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		vt8500_stop_tx(port);
		return;
	}

	while ((vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16) {
		if (uart_circ_empty(xmit))
			break;

		writeb(xmit->buf[xmit->tail], port->membase + VT8500_TXFIFO);

		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;
	}

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

	if (uart_circ_empty(xmit))
		vt8500_stop_tx(port);
}

static void vt8500_start_tx(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier &= ~TX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
	handle_tx(port);
	vt8500_port->ier |= TX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void handle_delta_cts(struct uart_port *port)
{
	port->icount.cts++;
	wake_up_interruptible(&port->state->port.delta_msr_wait);
}

static irqreturn_t vt8500_irq(int irq, void *dev_id)
{
	struct uart_port *port = dev_id;
	unsigned long isr;

	spin_lock(&port->lock);
	isr = vt8500_read(port, VT8500_URISR);

	/* Acknowledge active status bits */
	vt8500_write(port, isr, VT8500_URISR);

	if (isr & RX_FIFO_INTS)
		handle_rx(port);
	if (isr & TX_FIFO_INTS)
		handle_tx(port);
	if (isr & TCTS)
		handle_delta_cts(port);

	spin_unlock(&port->lock);

	return IRQ_HANDLED;
}

static unsigned int vt8500_tx_empty(struct uart_port *port)
{
	return (vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16 ?
						TIOCSER_TEMT : 0;
}

static unsigned int vt8500_get_mctrl(struct uart_port *port)
{
	unsigned int usr;

	usr = vt8500_read(port, VT8500_URUSR);
	if (usr & (1 << 4))
		return TIOCM_CTS;
	else
		return 0;
}

static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}

static void vt8500_break_ctl(struct uart_port *port, int break_ctl)
{
	if (break_ctl)
		vt8500_write(port, vt8500_read(port, VT8500_URLCR) | (1 << 9),
			     VT8500_URLCR);
}

static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud)
{
	unsigned long div;
	unsigned int loops = 1000;

	div = vt8500_read(port, VT8500_URDIV) & ~(0x3ff);

	if (unlikely((baud < 900) || (baud > 921600)))
		div |= 7;
	else
		div |= (921600 / baud) - 1;

	while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops)
		cpu_relax();
	vt8500_write(port, div, VT8500_URDIV);

	return baud;
}

static int vt8500_startup(struct uart_port *port)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);
	int ret;

	snprintf(vt8500_port->name, sizeof(vt8500_port->name),
		 "vt8500_serial%d", port->line);

	ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH,
			  vt8500_port->name, port);
	if (unlikely(ret))
		return ret;

	vt8500_write(port, 0x03, VT8500_URLCR);	/* enable TX & RX */

	return 0;
}

static void vt8500_shutdown(struct uart_port *port)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);

	vt8500_port->ier = 0;

	/* disable interrupts and FIFOs */
	vt8500_write(&vt8500_port->uart, 0, VT8500_URIER);
	vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR);
	free_irq(port->irq, port);
}

static void vt8500_set_termios(struct uart_port *port,
			       struct ktermios *termios,
			       struct ktermios *old)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);
	unsigned long flags;
	unsigned int baud, lcr;
	unsigned int loops = 1000;

	spin_lock_irqsave(&port->lock, flags);

	/* calculate and set baud rate */
	baud = uart_get_baud_rate(port, termios, old, 900, 921600);
	baud = vt8500_set_baud_rate(port, baud);
	if (tty_termios_baud_rate(termios))
		tty_termios_encode_baud_rate(termios, baud, baud);

	/* calculate parity */
	lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR);
	lcr &= ~((1 << 5) | (1 << 4));
	if (termios->c_cflag & PARENB) {
		lcr |= (1 << 4);
		termios->c_cflag &= ~CMSPAR;
		if (termios->c_cflag & PARODD)
			lcr |= (1 << 5);
	}

	/* calculate bits per char */
	lcr &= ~(1 << 2);
	switch (termios->c_cflag & CSIZE) {
	case CS7:
		break;
	case CS8:
	default:
		lcr |= (1 << 2);
		termios->c_cflag &= ~CSIZE;
		termios->c_cflag |= CS8;
		break;
	}

	/* calculate stop bits */
	lcr &= ~(1 << 3);
	if (termios->c_cflag & CSTOPB)
		lcr |= (1 << 3);

	/* set parity, bits per char, and stop bit */
	vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR);

	/* Configure status bits to ignore based on termio flags. */
	port->read_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		port->read_status_mask = FER | PER;

	uart_update_timeout(port, termios->c_cflag, baud);

	/* Reset FIFOs */
	vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR);
	while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc)
							&& --loops)
		cpu_relax();

	/* Every possible FIFO-related interrupt */
	vt8500_port->ier = RX_FIFO_INTS | TX_FIFO_INTS;

	/*
	 * CTS flow control
	 */
	if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag))
		vt8500_port->ier |= TCTS;

	vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR);
	vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER);

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

static const char *vt8500_type(struct uart_port *port)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);
	return vt8500_port->name;
}

static void vt8500_release_port(struct uart_port *port)
{
}

static int vt8500_request_port(struct uart_port *port)
{
	return 0;
}

static void vt8500_config_port(struct uart_port *port, int flags)
{
	port->type = PORT_VT8500;
}

static int vt8500_verify_port(struct uart_port *port,
			      struct serial_struct *ser)
{
	if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500))
		return -EINVAL;
	if (unlikely(port->irq != ser->irq))
		return -EINVAL;
	return 0;
}

static struct vt8500_port *vt8500_uart_ports[4];
static struct uart_driver vt8500_uart_driver;

#ifdef CONFIG_SERIAL_VT8500_CONSOLE

static inline void wait_for_xmitr(struct uart_port *port)
{
	unsigned int status, tmout = 10000;

	/* Wait up to 10ms for the character(s) to be sent. */
	do {
		status = vt8500_read(port, VT8500_URFIDX);

		if (--tmout == 0)
			break;
		udelay(1);
	} while (status & 0x10);
}

static void vt8500_console_putchar(struct uart_port *port, int c)
{
	wait_for_xmitr(port);
	writeb(c, port->membase + VT8500_TXFIFO);
}

static void vt8500_console_write(struct console *co, const char *s,
			      unsigned int count)
{
	struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index];
	unsigned long ier;

	BUG_ON(co->index < 0 || co->index >= vt8500_uart_driver.nr);

	ier = vt8500_read(&vt8500_port->uart, VT8500_URIER);
	vt8500_write(&vt8500_port->uart, VT8500_URIER, 0);

	uart_console_write(&vt8500_port->uart, s, count,
			   vt8500_console_putchar);

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and switch back to FIFO
	 */
	wait_for_xmitr(&vt8500_port->uart);
	vt8500_write(&vt8500_port->uart, VT8500_URIER, ier);
}

static int __init vt8500_console_setup(struct console *co, char *options)
{
	struct vt8500_port *vt8500_port;
	int baud = 9600;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	if (unlikely(co->index >= vt8500_uart_driver.nr || co->index < 0))
		return -ENXIO;

	vt8500_port = vt8500_uart_ports[co->index];

	if (!vt8500_port)
		return -ENODEV;

	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);

	return uart_set_options(&vt8500_port->uart,
				 co, baud, parity, bits, flow);
}

static struct console vt8500_console = {
	.name = "ttyWMT",
	.write = vt8500_console_write,
	.device = uart_console_device,
	.setup = vt8500_console_setup,
	.flags = CON_PRINTBUFFER,
	.index = -1,
	.data = &vt8500_uart_driver,
};

#define VT8500_CONSOLE	(&vt8500_console)

#else
#define VT8500_CONSOLE	NULL
#endif

static struct uart_ops vt8500_uart_pops = {
	.tx_empty	= vt8500_tx_empty,
	.set_mctrl	= vt8500_set_mctrl,
	.get_mctrl	= vt8500_get_mctrl,
	.stop_tx	= vt8500_stop_tx,
	.start_tx	= vt8500_start_tx,
	.stop_rx	= vt8500_stop_rx,
	.enable_ms	= vt8500_enable_ms,
	.break_ctl	= vt8500_break_ctl,
	.startup	= vt8500_startup,
	.shutdown	= vt8500_shutdown,
	.set_termios	= vt8500_set_termios,
	.type		= vt8500_type,
	.release_port	= vt8500_release_port,
	.request_port	= vt8500_request_port,
	.config_port	= vt8500_config_port,
	.verify_port	= vt8500_verify_port,
};

static struct uart_driver vt8500_uart_driver = {
	.owner		= THIS_MODULE,
	.driver_name	= "vt8500_serial",
	.dev_name	= "ttyWMT",
	.nr		= 6,
	.cons		= VT8500_CONSOLE,
};

547
static int __devinit vt8500_serial_probe(struct platform_device *pdev)
548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575
{
	struct vt8500_port *vt8500_port;
	struct resource *mmres, *irqres;
	int ret;

	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!mmres || !irqres)
		return -ENODEV;

	vt8500_port = kzalloc(sizeof(struct vt8500_port), GFP_KERNEL);
	if (!vt8500_port)
		return -ENOMEM;

	vt8500_port->uart.type = PORT_VT8500;
	vt8500_port->uart.iotype = UPIO_MEM;
	vt8500_port->uart.mapbase = mmres->start;
	vt8500_port->uart.irq = irqres->start;
	vt8500_port->uart.fifosize = 16;
	vt8500_port->uart.ops = &vt8500_uart_pops;
	vt8500_port->uart.line = pdev->id;
	vt8500_port->uart.dev = &pdev->dev;
	vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
	vt8500_port->uart.uartclk = 24000000;

	snprintf(vt8500_port->name, sizeof(vt8500_port->name),
		 "VT8500 UART%d", pdev->id);

576
	vt8500_port->uart.membase = ioremap(mmres->start, resource_size(mmres));
577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607
	if (!vt8500_port->uart.membase) {
		ret = -ENOMEM;
		goto err;
	}

	vt8500_uart_ports[pdev->id] = vt8500_port;

	uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);

	platform_set_drvdata(pdev, vt8500_port);

	return 0;

err:
	kfree(vt8500_port);
	return ret;
}

static int __devexit vt8500_serial_remove(struct platform_device *pdev)
{
	struct vt8500_port *vt8500_port = platform_get_drvdata(pdev);

	platform_set_drvdata(pdev, NULL);
	uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart);
	kfree(vt8500_port);

	return 0;
}

static struct platform_driver vt8500_platform_driver = {
	.probe  = vt8500_serial_probe,
608
	.remove = __devexit_p(vt8500_serial_remove),
609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645
	.driver = {
		.name = "vt8500_serial",
		.owner = THIS_MODULE,
	},
};

static int __init vt8500_serial_init(void)
{
	int ret;

	ret = uart_register_driver(&vt8500_uart_driver);
	if (unlikely(ret))
		return ret;

	ret = platform_driver_register(&vt8500_platform_driver);

	if (unlikely(ret))
		uart_unregister_driver(&vt8500_uart_driver);

	return ret;
}

static void __exit vt8500_serial_exit(void)
{
#ifdef CONFIG_SERIAL_VT8500_CONSOLE
	unregister_console(&vt8500_console);
#endif
	platform_driver_unregister(&vt8500_platform_driver);
	uart_unregister_driver(&vt8500_uart_driver);
}

module_init(vt8500_serial_init);
module_exit(vt8500_serial_exit);

MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
MODULE_DESCRIPTION("Driver for vt8500 serial device");
MODULE_LICENSE("GPL");
新手
引导
客服 返回
顶部