ar71xx: add NAND driver for the Mikrotik RB91x boards

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

SVN-Revision: 39097

1 files changed, 355 insertions, 0 deletions

diff --git a/target/linux/ar71xx/files/drivers/mtd/nand/rb91x_nand.c b/target/linux/ar71xx/files/drivers/mtd/nand/rb91x_nand.c
new file mode 100644
index 0000000..99828cb
--- /dev/null
+++ b/target/linux/ar71xx/files/drivers/mtd/nand/rb91x_nand.c
@@ -0,0 +1,355 @@
+/*
+ *  NAND flash driver for the MikroTik RouterBOARD 91x series
+ *
+ *  Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
+ *
+ *  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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include <asm/mach-ath79/ath79.h>
+
+#define DRV_NAME	"rb91x-nand"
+#define DRV_DESC	"NAND flash driver for the RouterBOARD 91x series"
+
+#define RB91X_NAND_NRE_ENABLE	BIT(3)
+#define RB91X_NAND_RDY		BIT(4)
+#define RB91X_LATCH_ENABLE	BIT(11)
+#define RB91X_NAND_NRWE		BIT(12)
+#define RB91X_NAND_NCE		BIT(13)
+#define RB91X_NAND_CLE		BIT(14)
+#define RB91X_NAND_ALE		BIT(15)
+
+#define RB91X_NAND_DATA_BITS	(BIT(0) | BIT(1) | BIT(2) | BIT(3) | BIT(4) |\
+				 BIT(13) | BIT(14) | BIT(15))
+
+#define RB91X_NAND_INPUT_BITS	(RB91X_NAND_DATA_BITS | RB91X_NAND_RDY)
+#define RB91X_NAND_OUTPUT_BITS	\
+	(RB91X_NAND_DATA_BITS | RB91X_NAND_NRWE)
+
+#define RB91X_NAND_LOW_DATA_MASK	0x1f
+#define RB91X_NAND_HIGH_DATA_MASK	0xe0
+#define RB91X_NAND_HIGH_DATA_SHIFT	8
+
+struct rb91x_nand_info {
+	struct nand_chip	chip;
+	struct mtd_info		mtd;
+};
+
+static inline struct rb91x_nand_info *mtd_to_rbinfo(struct mtd_info *mtd)
+{
+	return container_of(mtd, struct rb91x_nand_info, mtd);
+}
+
+/*
+ * We need to use the OLD Yaffs-1 OOB layout, otherwise the RB bootloader
+ * will not be able to find the kernel that we load.
+ */
+static struct nand_ecclayout rb91x_nand_ecclayout = {
+	.eccbytes	= 6,
+	.eccpos		= { 8, 9, 10, 13, 14, 15 },
+	.oobavail	= 9,
+	.oobfree	= { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }
+};
+
+static struct mtd_partition rb91x_nand_partitions[] = {
+	{
+		.name	= "booter",
+		.offset	= 0,
+		.size	= (256 * 1024),
+		.mask_flags = MTD_WRITEABLE,
+	}, {
+		.name	= "kernel",
+		.offset	= (256 * 1024),
+		.size	= (4 * 1024 * 1024) - (256 * 1024),
+	}, {
+		.name	= "rootfs",
+		.offset	= MTDPART_OFS_NXTBLK,
+		.size	= MTDPART_SIZ_FULL,
+	},
+};
+
+static void rb91x_change_gpo(u32 clear, u32 set)
+{
+	void __iomem *base = ath79_gpio_base;
+	static unsigned on = 0xE002800;
+	static unsigned off = 0x0000C008;
+	static unsigned oe = 0;
+	static DEFINE_SPINLOCK(lock);
+	unsigned long flags;
+
+	spin_lock_irqsave(&lock, flags);
+
+	on = (on | set) & ~clear;
+	off = (off | clear) & ~set;
+
+	if (!oe)
+		oe = __raw_readl(base + AR71XX_GPIO_REG_OE);
+
+	if (on & RB91X_LATCH_ENABLE) {
+		u32 t;
+
+		t = oe & __raw_readl(base + AR71XX_GPIO_REG_OE);
+		t &= ~(on | off);
+		__raw_writel(t, base + AR71XX_GPIO_REG_OE);
+		__raw_writel(off, base + AR71XX_GPIO_REG_CLEAR);
+		__raw_writel(on, base + AR71XX_GPIO_REG_SET);
+	} else if (clear & RB91X_LATCH_ENABLE) {
+		oe = __raw_readl(base + AR71XX_GPIO_REG_OE);
+		__raw_writel(RB91X_LATCH_ENABLE,
+			     base + AR71XX_GPIO_REG_CLEAR);
+		/* flush write */
+		__raw_readl(base + AR71XX_GPIO_REG_CLEAR);
+	}
+
+	spin_unlock_irqrestore(&lock, flags);
+}
+
+static inline void rb91x_latch_enable(void)
+{
+	rb91x_change_gpo(RB91X_LATCH_ENABLE, 0);
+}
+
+static inline void rb91x_latch_disable(void)
+{
+	rb91x_change_gpo(0, RB91X_LATCH_ENABLE);
+}
+
+static void rb91x_nand_write(const u8 *buf, unsigned len)
+{
+	void __iomem *base = ath79_gpio_base;
+	u32 oe_reg;
+	u32 out_reg;
+	u32 out;
+	unsigned i;
+
+	rb91x_latch_enable();
+
+	oe_reg = __raw_readl(base + AR71XX_GPIO_REG_OE);
+	out_reg = __raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+	/* set data lines to output mode */
+	__raw_writel(oe_reg & ~(RB91X_NAND_DATA_BITS | RB91X_NAND_NRWE),
+		     base + AR71XX_GPIO_REG_OE);
+
+	out = out_reg & ~(RB91X_NAND_DATA_BITS | RB91X_NAND_NRWE);
+	for (i = 0; i != len; i++) {
+		u32 data;
+
+		data = (buf[i] & RB91X_NAND_HIGH_DATA_MASK) <<
+			RB91X_NAND_HIGH_DATA_SHIFT;
+		data |= buf[i] & RB91X_NAND_LOW_DATA_MASK;
+		data |= out;
+		__raw_writel(data, base + AR71XX_GPIO_REG_OUT);
+
+		/* deactivate WE line */
+		data |= RB91X_NAND_NRWE;
+		__raw_writel(data, base + AR71XX_GPIO_REG_OUT);
+		/* flush write */
+		__raw_readl(base + AR71XX_GPIO_REG_OUT);
+	}
+
+	/* restore  registers */
+	__raw_writel(oe_reg, base + AR71XX_GPIO_REG_OE);
+	__raw_writel(out_reg, base + AR71XX_GPIO_REG_OUT);
+	/* flush write */
+	__raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+	rb91x_latch_disable();
+}
+
+static void rb91x_nand_read(u8 *read_buf, unsigned len)
+{
+	void __iomem *base = ath79_gpio_base;
+	u32 oe_reg;
+	u32 out_reg;
+	unsigned i;
+
+	/* save registers */
+	oe_reg = __raw_readl(base + AR71XX_GPIO_REG_OE);
+
+	/* select nRE mode */
+	rb91x_change_gpo(0, RB91X_NAND_NRE_ENABLE);
+
+	/* enable latch */
+	rb91x_latch_enable();
+
+	out_reg = __raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+	/* set data lines to input mode */
+	__raw_writel(oe_reg | RB91X_NAND_DATA_BITS,
+		     base + AR71XX_GPIO_REG_OE);
+
+	for (i = 0; i < len; i++) {
+		u32 in;
+		u8 data;
+
+		/* activate RE line */
+		__raw_writel(RB91X_NAND_NRWE, base + AR71XX_GPIO_REG_CLEAR);
+		/* flush write */
+		__raw_readl(base + AR71XX_GPIO_REG_CLEAR);
+
+		/* read input lines */
+		in = __raw_readl(base + AR71XX_GPIO_REG_IN);
+
+		/* deactivate RE line */
+		__raw_writel(RB91X_NAND_NRWE, base + AR71XX_GPIO_REG_SET);
+
+		data = (in & RB91X_NAND_LOW_DATA_MASK);
+		data |= (in >> RB91X_NAND_HIGH_DATA_SHIFT) &
+			RB91X_NAND_HIGH_DATA_MASK;
+
+		read_buf[i] = data;
+	}
+
+	/* restore  registers */
+	__raw_writel(oe_reg, base + AR71XX_GPIO_REG_OE);
+	__raw_writel(out_reg, base + AR71XX_GPIO_REG_OUT);
+	/* flush write */
+	__raw_readl(base + AR71XX_GPIO_REG_OUT);
+
+	/* disable latch */
+	rb91x_latch_disable();
+
+	/* deselect nRE mode */
+	rb91x_change_gpo(RB91X_NAND_NRE_ENABLE, 0);
+}
+
+static int rb91x_nand_dev_ready(struct mtd_info *mtd)
+{
+	void __iomem *base = ath79_gpio_base;
+
+	return !!(__raw_readl(base + AR71XX_GPIO_REG_IN) & RB91X_NAND_RDY);
+}
+
+static void rb91x_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
+				unsigned int ctrl)
+{
+	if (ctrl & NAND_CTRL_CHANGE) {
+		u32 on = 0;
+		u32 off;
+
+		if (!(ctrl & NAND_NCE))
+			on |= RB91X_NAND_NCE;
+
+		if (ctrl & NAND_CLE)
+			on |= RB91X_NAND_CLE;
+
+		if (ctrl & NAND_ALE)
+			on |= RB91X_NAND_ALE;
+
+		off = on ^ (RB91X_NAND_ALE | RB91X_NAND_NCE | RB91X_NAND_CLE);
+		rb91x_change_gpo(off, on);
+	}
+
+	if (cmd != NAND_CMD_NONE) {
+		u8 t = cmd;
+
+		rb91x_nand_write(&t, 1);
+	}
+}
+
+static u8 rb91x_nand_read_byte(struct mtd_info *mtd)
+{
+	u8 data = 0xff;
+
+	rb91x_nand_read(&data, 1);
+
+	return data;
+}
+
+static void rb91x_nand_read_buf(struct mtd_info *mtd, u8 *buf, int len)
+{
+	rb91x_nand_read(buf, len);
+}
+
+static void rb91x_nand_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
+{
+	rb91x_nand_write(buf, len);
+}
+
+static int rb91x_nand_probe(struct platform_device *pdev)
+{
+	struct rb91x_nand_info	*info;
+	int ret;
+
+	pr_info(DRV_DESC "\n");
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->chip.priv	= &info;
+	info->mtd.priv	= &info->chip;
+	info->mtd.owner	= THIS_MODULE;
+
+	info->chip.cmd_ctrl	= rb91x_nand_cmd_ctrl;
+	info->chip.dev_ready	= rb91x_nand_dev_ready;
+	info->chip.read_byte	= rb91x_nand_read_byte;
+	info->chip.write_buf	= rb91x_nand_write_buf;
+	info->chip.read_buf	= rb91x_nand_read_buf;
+
+	info->chip.chip_delay	= 25;
+	info->chip.ecc.mode	= NAND_ECC_SOFT;
+
+	platform_set_drvdata(pdev, info);
+
+	ret = nand_scan_ident(&info->mtd, 1, NULL);
+	if (ret)
+		return ret;
+
+	if (info->mtd.writesize == 512)
+		info->chip.ecc.layout = &rb91x_nand_ecclayout;
+
+	ret = nand_scan_tail(&info->mtd);
+	if (ret)
+		return ret;
+
+	ret = mtd_device_register(&info->mtd, rb91x_nand_partitions,
+				 ARRAY_SIZE(rb91x_nand_partitions));
+	if (ret)
+		goto err_release_nand;
+
+	return 0;
+
+err_release_nand:
+	nand_release(&info->mtd);
+	return ret;
+}
+
+static int rb91x_nand_remove(struct platform_device *pdev)
+{
+	struct rb91x_nand_info *info = platform_get_drvdata(pdev);
+
+	nand_release(&info->mtd);
+
+	return 0;
+}
+
+static struct platform_driver rb91x_nand_driver = {
+	.probe	= rb91x_nand_probe,
+	.remove	= rb91x_nand_remove,
+	.driver	= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_platform_driver(rb91x_nand_driver);
+
+MODULE_DESCRIPTION(DRV_DESC);
+MODULE_VERSION(DRV_VERSION);
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_LICENSE("GPL v2");