[PATCH] AVR32 MTD: Static Memory Controller driver

This patchset adds the necessary drivers and infrastructure to access the
external flash on the ATSTK1000 board through the MTD subsystem.  With this
stuff in place, it will be possible to use a jffs2 filesystem stored in the
external flash as a root filesystem.  It might also be possible to update the
boot loader if you drop the write protection of partition 0.

As suggested by David Woodhouse, I reworked the patches to use the physmap
driver instead of introducing a separate mapping driver for the ATSTK1000.
I've also cleaned up the hsmc header by removing useless comments and
converting spaces to tabs (my headerfile generator needs some work.)

Unfortunately, I couldn't unlock the flash in fixup_use_atmel_lock because the
erase regions hadn't been set up yet, so I had to do it from cfi_amdstd_setup
instead.

This patch:

This adds a simple API for configuring the static memory controller along with
an implementation for the Atmel HSMC.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/avr32/mach-at32ap/Makefile

-obj-y				+= at32ap.o clock.o pio.o intc.o extint.o
+obj-y				+= at32ap.o clock.o pio.o intc.o extint.o hsmc.o
 obj-$(CONFIG_CPU_AT32AP7000)	+= at32ap7000.o

arch/avr32/mach-at32ap/at32ap7000.c

@@ -450,6 +450,13 @@ static struct clk hramc_clk = {
 	.users		= 1,
 };
 
+static struct resource smc0_resource[] = {
+	PBMEM(0xfff03400),
+};
+DEFINE_DEV(smc, 0);
+DEV_CLK(pclk, smc0, pbb, 13);
+DEV_CLK(mck, smc0, hsb, 0);
+
 static struct platform_device pdc_device = {
 	.name		= "pdc",
 	.id		= 0,
@@ -503,6 +510,7 @@ void __init at32_add_system_devices(void)
 
 	platform_device_register(&at32_sm_device);
 	platform_device_register(&at32_intc0_device);
+	platform_device_register(&smc0_device);
 	platform_device_register(&pdc_device);
 
 	platform_device_register(&pio0_device);
@@ -796,6 +804,8 @@ struct clk *at32_clock_list[] = {
 	&at32_intc0_pclk,
 	&ebi_clk,
 	&hramc_clk,
+	&smc0_pclk,
+	&smc0_mck,
 	&pdc_hclk,
 	&pdc_pclk,
 	&pico_clk,

arch/avr32/mach-at32ap/hsmc.c

+/*
+ * Static Memory Controller for AT32 chips
+ *
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define DEBUG
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <asm/io.h>
+#include <asm/arch/smc.h>
+
+#include "hsmc.h"
+
+#define NR_CHIP_SELECTS 6
+
+struct hsmc {
+	void __iomem *regs;
+	struct clk *pclk;
+	struct clk *mck;
+};
+
+static struct hsmc *hsmc;
+
+int smc_set_configuration(int cs, const struct smc_config *config)
+{
+	unsigned long mul;
+	unsigned long offset;
+	u32 setup, pulse, cycle, mode;
+
+	if (!hsmc)
+		return -ENODEV;
+	if (cs >= NR_CHIP_SELECTS)
+		return -EINVAL;
+
+	/*
+	 * cycles = x / T = x * f
+	 *   = ((x * 1000000000) * ((f * 65536) / 1000000000)) / 65536
+	 *   = ((x * 1000000000) * (((f / 10000) * 65536) / 100000)) / 65536
+	 */
+	mul = (clk_get_rate(hsmc->mck) / 10000) << 16;
+	mul /= 100000;
+
+#define ns2cyc(x) ((((x) * mul) + 65535) >> 16)
+
+	setup = (HSMC_BF(NWE_SETUP, ns2cyc(config->nwe_setup))
+		 | HSMC_BF(NCS_WR_SETUP, ns2cyc(config->ncs_write_setup))
+		 | HSMC_BF(NRD_SETUP, ns2cyc(config->nrd_setup))
+		 | HSMC_BF(NCS_RD_SETUP, ns2cyc(config->ncs_read_setup)));
+	pulse = (HSMC_BF(NWE_PULSE, ns2cyc(config->nwe_pulse))
+		 | HSMC_BF(NCS_WR_PULSE, ns2cyc(config->ncs_write_pulse))
+		 | HSMC_BF(NRD_PULSE, ns2cyc(config->nrd_pulse))
+		 | HSMC_BF(NCS_RD_PULSE, ns2cyc(config->ncs_read_pulse)));
+	cycle = (HSMC_BF(NWE_CYCLE, ns2cyc(config->write_cycle))
+		 | HSMC_BF(NRD_CYCLE, ns2cyc(config->read_cycle)));
+
+	switch (config->bus_width) {
+	case 1:
+		mode = HSMC_BF(DBW, HSMC_DBW_8_BITS);
+		break;
+	case 2:
+		mode = HSMC_BF(DBW, HSMC_DBW_16_BITS);
+		break;
+	case 4:
+		mode = HSMC_BF(DBW, HSMC_DBW_32_BITS);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (config->nrd_controlled)
+		mode |= HSMC_BIT(READ_MODE);
+	if (config->nwe_controlled)
+		mode |= HSMC_BIT(WRITE_MODE);
+	if (config->byte_write)
+		mode |= HSMC_BIT(BAT);
+
+	pr_debug("smc cs%d: setup/%08x pulse/%08x cycle/%08x mode/%08x\n",
+		 cs, setup, pulse, cycle, mode);
+
+	offset = cs * 0x10;
+	hsmc_writel(hsmc, SETUP0 + offset, setup);
+	hsmc_writel(hsmc, PULSE0 + offset, pulse);
+	hsmc_writel(hsmc, CYCLE0 + offset, cycle);
+	hsmc_writel(hsmc, MODE0 + offset, mode);
+	hsmc_readl(hsmc, MODE0); /* I/O barrier */
+
+	return 0;
+}
+EXPORT_SYMBOL(smc_set_configuration);
+
+static int hsmc_probe(struct platform_device *pdev)
+{
+	struct resource *regs;
+	struct clk *pclk, *mck;
+	int ret;
+
+	if (hsmc)
+		return -EBUSY;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs)
+		return -ENXIO;
+	pclk = clk_get(&pdev->dev, "pclk");
+	if (IS_ERR(pclk))
+		return PTR_ERR(pclk);
+	mck = clk_get(&pdev->dev, "mck");
+	if (IS_ERR(mck)) {
+		ret = PTR_ERR(mck);
+		goto out_put_pclk;
+	}
+
+	ret = -ENOMEM;
+	hsmc = kzalloc(sizeof(struct hsmc), GFP_KERNEL);
+	if (!hsmc)
+		goto out_put_clocks;
+
+	clk_enable(pclk);
+	clk_enable(mck);
+
+	hsmc->pclk = pclk;
+	hsmc->mck = mck;
+	hsmc->regs = ioremap(regs->start, regs->end - regs->start + 1);
+	if (!hsmc->regs)
+		goto out_disable_clocks;
+
+	dev_info(&pdev->dev, "Atmel Static Memory Controller at 0x%08lx\n",
+		 (unsigned long)regs->start);
+
+	platform_set_drvdata(pdev, hsmc);
+
+	return 0;
+
+out_disable_clocks:
+	clk_disable(mck);
+	clk_disable(pclk);
+	kfree(hsmc);
+out_put_clocks:
+	clk_put(mck);
+out_put_pclk:
+	clk_put(pclk);
+	hsmc = NULL;
+	return ret;
+}
+
+static struct platform_driver hsmc_driver = {
+	.probe		= hsmc_probe,
+	.driver		= {
+		.name	= "smc",
+	},
+};
+
+static int __init hsmc_init(void)
+{
+	return platform_driver_register(&hsmc_driver);
+}
+arch_initcall(hsmc_init);

arch/avr32/mach-at32ap/hsmc.h

+/*
+ * Register definitions for Atmel Static Memory Controller (SMC)
+ *
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __ASM_AVR32_HSMC_H__
+#define __ASM_AVR32_HSMC_H__
+
+/* HSMC register offsets */
+#define HSMC_SETUP0				0x0000
+#define HSMC_PULSE0				0x0004
+#define HSMC_CYCLE0				0x0008
+#define HSMC_MODE0				0x000c
+#define HSMC_SETUP1				0x0010
+#define HSMC_PULSE1				0x0014
+#define HSMC_CYCLE1				0x0018
+#define HSMC_MODE1				0x001c
+#define HSMC_SETUP2				0x0020
+#define HSMC_PULSE2				0x0024
+#define HSMC_CYCLE2				0x0028
+#define HSMC_MODE2				0x002c
+#define HSMC_SETUP3				0x0030
+#define HSMC_PULSE3				0x0034
+#define HSMC_CYCLE3				0x0038
+#define HSMC_MODE3				0x003c
+#define HSMC_SETUP4				0x0040
+#define HSMC_PULSE4				0x0044
+#define HSMC_CYCLE4				0x0048
+#define HSMC_MODE4				0x004c
+#define HSMC_SETUP5				0x0050
+#define HSMC_PULSE5				0x0054
+#define HSMC_CYCLE5				0x0058
+#define HSMC_MODE5				0x005c
+
+/* Bitfields in SETUP0 */
+#define HSMC_NWE_SETUP_OFFSET			0
+#define HSMC_NWE_SETUP_SIZE			6
+#define HSMC_NCS_WR_SETUP_OFFSET		8
+#define HSMC_NCS_WR_SETUP_SIZE			6
+#define HSMC_NRD_SETUP_OFFSET			16
+#define HSMC_NRD_SETUP_SIZE			6
+#define HSMC_NCS_RD_SETUP_OFFSET		24
+#define HSMC_NCS_RD_SETUP_SIZE			6
+
+/* Bitfields in PULSE0 */
+#define HSMC_NWE_PULSE_OFFSET			0
+#define HSMC_NWE_PULSE_SIZE			7
+#define HSMC_NCS_WR_PULSE_OFFSET		8
+#define HSMC_NCS_WR_PULSE_SIZE			7
+#define HSMC_NRD_PULSE_OFFSET			16
+#define HSMC_NRD_PULSE_SIZE			7
+#define HSMC_NCS_RD_PULSE_OFFSET		24
+#define HSMC_NCS_RD_PULSE_SIZE			7
+
+/* Bitfields in CYCLE0 */
+#define HSMC_NWE_CYCLE_OFFSET			0
+#define HSMC_NWE_CYCLE_SIZE			9
+#define HSMC_NRD_CYCLE_OFFSET			16
+#define HSMC_NRD_CYCLE_SIZE			9
+
+/* Bitfields in MODE0 */
+#define HSMC_READ_MODE_OFFSET			0
+#define HSMC_READ_MODE_SIZE			1
+#define HSMC_WRITE_MODE_OFFSET			1
+#define HSMC_WRITE_MODE_SIZE			1
+#define HSMC_EXNW_MODE_OFFSET			4
+#define HSMC_EXNW_MODE_SIZE			2
+#define HSMC_BAT_OFFSET				8
+#define HSMC_BAT_SIZE				1
+#define HSMC_DBW_OFFSET				12
+#define HSMC_DBW_SIZE				2
+#define HSMC_TDF_CYCLES_OFFSET			16
+#define HSMC_TDF_CYCLES_SIZE			4
+#define HSMC_TDF_MODE_OFFSET			20
+#define HSMC_TDF_MODE_SIZE			1
+#define HSMC_PMEN_OFFSET			24
+#define HSMC_PMEN_SIZE				1
+#define HSMC_PS_OFFSET				28
+#define HSMC_PS_SIZE				2
+
+/* Constants for READ_MODE */
+#define HSMC_READ_MODE_NCS_CONTROLLED		0
+#define HSMC_READ_MODE_NRD_CONTROLLED		1
+
+/* Constants for WRITE_MODE */
+#define HSMC_WRITE_MODE_NCS_CONTROLLED		0
+#define HSMC_WRITE_MODE_NWE_CONTROLLED		1
+
+/* Constants for EXNW_MODE */
+#define HSMC_EXNW_MODE_DISABLED			0
+#define HSMC_EXNW_MODE_RESERVED			1
+#define HSMC_EXNW_MODE_FROZEN			2
+#define HSMC_EXNW_MODE_READY			3
+
+/* Constants for BAT */
+#define HSMC_BAT_BYTE_SELECT			0
+#define HSMC_BAT_BYTE_WRITE			1
+
+/* Constants for DBW */
+#define HSMC_DBW_8_BITS				0
+#define HSMC_DBW_16_BITS			1
+#define HSMC_DBW_32_BITS			2
+
+/* Bit manipulation macros */
+#define HSMC_BIT(name)							\
+	(1 << HSMC_##name##_OFFSET)
+#define HSMC_BF(name,value)						\
+	(((value) & ((1 << HSMC_##name##_SIZE) - 1))			\
+	 << HSMC_##name##_OFFSET)
+#define HSMC_BFEXT(name,value)						\
+	(((value) >> HSMC_##name##_OFFSET)				\
+	 & ((1 << HSMC_##name##_SIZE) - 1))
+#define HSMC_BFINS(name,value,old)					\
+	(((old) & ~(((1 << HSMC_##name##_SIZE) - 1)			\
+		    << HSMC_##name##_OFFSET)) | HSMC_BF(name,value))
+
+/* Register access macros */
+#define hsmc_readl(port,reg)						\
+	readl((port)->regs + HSMC_##reg)
+#define hsmc_writel(port,reg,value)					\
+	writel((value), (port)->regs + HSMC_##reg)
+
+#endif /* __ASM_AVR32_HSMC_H__ */

include/asm-avr32/arch-at32ap/smc.h

+/*
+ * Static Memory Controller for AT32 chips
+ *
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * Inspired by the OMAP2 General-Purpose Memory Controller interface
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef __ARCH_AT32AP_SMC_H
+#define __ARCH_AT32AP_SMC_H
+
+/*
+ * All timing parameters are in nanoseconds.
+ */
+struct smc_config {
+	/* Delay from address valid to assertion of given strobe */
+	u16		ncs_read_setup;
+	u16		nrd_setup;
+	u16		ncs_write_setup;
+	u16		nwe_setup;
+
+	/* Pulse length of given strobe */
+	u16		ncs_read_pulse;
+	u16		nrd_pulse;
+	u16		ncs_write_pulse;
+	u16		nwe_pulse;
+
+	/* Total cycle length of given operation */
+	u16		read_cycle;
+	u16		write_cycle;
+
+	/* Bus width in bytes */
+	u8		bus_width;
+
+	/*
+	 * 0: Data is sampled on rising edge of NCS
+	 * 1: Data is sampled on rising edge of NRD
+	 */
+	unsigned int	nrd_controlled:1;
+
+	/*
+	 * 0: Data is driven on falling edge of NCS
+	 * 1: Data is driven on falling edge of NWR
+	 */
+	unsigned int	nwe_controlled:1;
+
+	/*
+	 * 0: Byte select access type
+	 * 1: Byte write access type
+	 */
+	unsigned int	byte_write:1;
+};
+
+extern int smc_set_configuration(int cs, const struct smc_config *config);
+extern struct smc_config *smc_get_configuration(int cs);
+
+#endif /* __ARCH_AT32AP_SMC_H */