[PATCH v2] nand: Add NAND driver for Mikrotik RB4xx series boards
From: Bert Vermeulen
Date: Thu May 07 2015 - 08:33:07 EST
The NAND chip containing the root filesystem is behind an SPI-connected
CPLD. This driver uses the spi-rb4xx driver to communicate with the CPLD.
The CPLD also acts as a GPIO expander: the ALE/CLE/NCE pins are set via
CPLD commands. Some LEDs on the board are also accessed this way.
Signed-off-by: Bert Vermeulen <bert@xxxxxxxx>
---
Changes in v2:
- Fix Kconfig dependencies and description
- Move NAND partitions into platform data
- Use gpiod API with lookup table, and devm_ as needed
- Code cleanup
arch/mips/include/asm/mach-ath79/rb4xx.h | 44 +++
drivers/mtd/nand/Kconfig | 7 +
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/rb4xx_nand.c | 482 +++++++++++++++++++++++++++++++
4 files changed, 534 insertions(+)
create mode 100644 arch/mips/include/asm/mach-ath79/rb4xx.h
create mode 100644 drivers/mtd/nand/rb4xx_nand.c
diff --git a/arch/mips/include/asm/mach-ath79/rb4xx.h b/arch/mips/include/asm/mach-ath79/rb4xx.h
new file mode 100644
index 0000000..667ea748
--- /dev/null
+++ b/arch/mips/include/asm/mach-ath79/rb4xx.h
@@ -0,0 +1,44 @@
+/*
+ * SPI driver definitions for the CPLD chip on the Mikrotik RB4xx boards
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ *
+ * This file was based on the patches for Linux 2.6.27.39 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * 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/spi/flash.h>
+
+#define RB4XX_GPIO_CPLD_BASE 32
+
+#define CPLD_GPIO_LED1 0
+#define CPLD_GPIO_LED2 2
+#define CPLD_GPIO_LED3 1
+#define CPLD_GPIO_LED4 3
+#define CPLD_GPIO_FAN 4
+#define CPLD_GPIO_ALE 5
+#define CPLD_GPIO_CLE 6
+#define CPLD_GPIO_NCE 7
+#define CPLD_GPIO_LED5 8
+
+#define CPLD_NUM_GPIOS 9
+
+#define CPLD_CFG_LED1 BIT(CPLD_GPIO_LED1)
+#define CPLD_CFG_LED2 BIT(CPLD_GPIO_LED2)
+#define CPLD_CFG_LED3 BIT(CPLD_GPIO_LED3)
+#define CPLD_CFG_LED4 BIT(CPLD_GPIO_LED4)
+#define CPLD_CFG_FAN BIT(CPLD_GPIO_FAN)
+#define CPLD_CFG_ALE BIT(CPLD_GPIO_ALE)
+#define CPLD_CFG_CLE BIT(CPLD_GPIO_CLE)
+#define CPLD_CFG_NCE BIT(CPLD_GPIO_NCE)
+#define CPLD_CFG_LED5 BIT(CPLD_GPIO_LED5)
+
+struct rb4xx_cpld_platform_data {
+ unsigned gpio_base;
+ struct flash_platform_data flash_data;
+};
+
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 5897d8d..873639f 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -530,4 +530,11 @@ config MTD_NAND_HISI504
help
Enables support for NAND controller on Hisilicon SoC Hip04.
+config MTD_NAND_RB4XX
+ tristate "NAND flash driver for Mikrotik RB4xx series boards"
+ depends on MTD_NAND && SPI_RB4XX
+ help
+ Enables support for the NAND flash chip on Mikrotik Routerboard
+ RB4xx series.
+
endif # MTD_NAND
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index 582bbd05..56dbd08 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -52,5 +52,6 @@ obj-$(CONFIG_MTD_NAND_XWAY) += xway_nand.o
obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH) += bcm47xxnflash/
obj-$(CONFIG_MTD_NAND_SUNXI) += sunxi_nand.o
obj-$(CONFIG_MTD_NAND_HISI504) += hisi504_nand.o
+obj-$(CONFIG_MTD_NAND_RB4XX) += rb4xx_nand.o
nand-objs := nand_base.o nand_bbt.o nand_timings.o
diff --git a/drivers/mtd/nand/rb4xx_nand.c b/drivers/mtd/nand/rb4xx_nand.c
new file mode 100644
index 0000000..d61ee2b
--- /dev/null
+++ b/drivers/mtd/nand/rb4xx_nand.c
@@ -0,0 +1,482 @@
+/*
+ * NAND flash driver for the MikroTik RouterBoard 4xx series
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@xxxxxxxxxxx>
+ * Copyright (C) 2015 Bert Vermeulen <bert@xxxxxxxx>
+ *
+ * This file was based on the driver for Linux 2.6.22 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * 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/mtd/nand.h>
+#include <linux/spi/spi.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/consumer.h>
+
+#include <asm/mach-ath79/rb4xx.h>
+
+#define CPLD_CMD_WRITE_NAND 0x08
+#define CPLD_CMD_WRITE_CFG 0x09
+#define CPLD_CMD_READ_NAND 0x0a
+#define CPLD_CMD_READ_FAST 0x0b
+#define CPLD_CMD_LED5_ON 0x0c
+#define CPLD_CMD_LED5_OFF 0x0d
+
+struct rb4xx_nand_info {
+ struct nand_chip chip;
+ struct mtd_info mtd;
+ struct spi_device *spi_dev;
+ struct gpio_desc *gpio_rdy;
+ struct gpio_desc *gpio_ale;
+ struct gpio_desc *gpio_cle;
+ struct gpio_desc *gpio_nce;
+};
+
+struct rb4xx_cpld {
+ struct spi_device *spi;
+ struct mutex lock;
+ struct gpio_chip chip;
+ unsigned int config;
+};
+
+/*
+ * 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 rb4xx_nand_ecclayout = {
+ .eccbytes = 6,
+ .eccpos = { 8, 9, 10, 13, 14, 15 },
+ .oobavail = 9,
+ .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }
+};
+
+static inline struct rb4xx_cpld *gpio_to_cpld(struct gpio_chip *chip)
+{
+ return container_of(chip, struct rb4xx_cpld, chip);
+}
+
+static int rb4xx_cpld_write_cmd(struct rb4xx_cpld *cpld, unsigned char cmd)
+{
+ struct spi_transfer t;
+ struct spi_message m;
+
+ spi_message_init(&m);
+
+ memset(&t, 0, sizeof(t));
+ t.tx_buf = &cmd;
+ t.len = sizeof(cmd);
+ spi_message_add_tail(&t, &m);
+ return spi_sync(cpld->spi, &m);
+}
+
+static int rb4xx_cpld_write_cfg(struct rb4xx_cpld *cpld, unsigned char config)
+{
+ struct spi_transfer t;
+ struct spi_message m;
+ unsigned char cmd[2] = {
+ CPLD_CMD_WRITE_CFG, config
+ };
+
+ spi_message_init(&m);
+
+ memset(&t, 0, sizeof(t));
+ t.tx_buf = cmd;
+ t.len = sizeof(cmd);
+ spi_message_add_tail(&t, &m);
+ return spi_sync(cpld->spi, &m);
+}
+
+static int rb4xx_cpld_change_cfg(struct rb4xx_cpld *cpld, u32 mask, u32 value)
+{
+ unsigned int config;
+ int ret;
+
+ config = cpld->config & ~mask;
+ config |= value;
+
+ if (mask & 0xff) {
+ ret = rb4xx_cpld_write_cfg(cpld, config);
+ if (ret)
+ return ret;
+ }
+
+ if (mask & CPLD_CFG_LED5) {
+ if (value & CPLD_CFG_LED5)
+ ret = rb4xx_cpld_write_cmd(cpld, CPLD_CMD_LED5_ON);
+ else
+ ret = rb4xx_cpld_write_cmd(cpld, CPLD_CMD_LED5_OFF);
+ if (ret)
+ return ret;
+ }
+
+ cpld->config = config;
+
+ return 0;
+}
+
+static int rb4xx_cpld_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+ int value;
+
+ mutex_lock(&cpld->lock);
+ value = (cpld->config >> offset) & 1;
+ mutex_unlock(&cpld->lock);
+
+ return value;
+}
+
+static void rb4xx_cpld_gpio_set(struct gpio_chip *chip,
+ unsigned offset, int value)
+{
+ struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+
+ mutex_lock(&cpld->lock);
+ rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
+ mutex_unlock(&cpld->lock);
+}
+
+static int rb4xx_cpld_gpio_direction_input(struct gpio_chip *chip,
+ unsigned offset)
+{
+ return -EOPNOTSUPP;
+}
+
+static int rb4xx_cpld_gpio_direction_output(struct gpio_chip *chip,
+ unsigned offset, int value)
+{
+ struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
+ int ret;
+
+ mutex_lock(&cpld->lock);
+ ret = rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
+ mutex_unlock(&cpld->lock);
+
+ return ret;
+}
+
+static int rb4xx_cpld_read(struct spi_device *spi, unsigned char *rx_buf,
+ unsigned len)
+{
+ struct spi_message m;
+ static const unsigned char cmd[2] = {
+ CPLD_CMD_READ_NAND, 0
+ };
+ struct spi_transfer t[2] = {
+ {
+ .tx_buf = &cmd,
+ .len = sizeof(cmd),
+ }, {
+ .rx_buf = rx_buf,
+ .len = len,
+ },
+ };
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t[0], &m);
+ spi_message_add_tail(&t[1], &m);
+ return spi_sync(spi, &m);
+}
+
+static int rb4xx_cpld_write(struct spi_device *spi, const u8 *buf, int len)
+{
+ struct spi_message m;
+ static const unsigned char cmd = CPLD_CMD_WRITE_NAND;
+ struct spi_transfer t[3] = {
+ {
+ .tx_buf = &cmd,
+ .len = sizeof(cmd),
+ }, {
+ .tx_buf = buf,
+ .len = len,
+ .tx_nbits = SPI_NBITS_DUAL,
+ }, {
+ .len = 1,
+ .tx_nbits = SPI_NBITS_DUAL,
+ },
+ };
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t[0], &m);
+ spi_message_add_tail(&t[1], &m);
+ spi_message_add_tail(&t[2], &m);
+ return spi_sync(spi, &m);
+}
+
+static int rb4xx_nand_dev_ready(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct rb4xx_nand_info *info = chip->priv;
+ return gpiod_get_value_cansleep(info->gpio_rdy);
+}
+
+static void rb4xx_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
+ unsigned int ctrl)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct rb4xx_nand_info *info = chip->priv;
+ u8 data = cmd;
+ int ret;
+
+ if (ctrl & NAND_CTRL_CHANGE) {
+ gpiod_set_value_cansleep(info->gpio_cle,
+ (ctrl & NAND_CLE) ? 1 : 0);
+ gpiod_set_value_cansleep(info->gpio_ale,
+ (ctrl & NAND_ALE) ? 1 : 0);
+ gpiod_set_value_cansleep(info->gpio_nce,
+ (ctrl & NAND_NCE) ? 0 : 1);
+ }
+
+ if (cmd != NAND_CMD_NONE) {
+ ret = rb4xx_cpld_write(info->spi_dev, &data, 1);
+ if (ret)
+ pr_err("rb4xx_nand: write cmd failed, error %d\n", ret);
+ }
+}
+
+static unsigned char rb4xx_nand_read_byte(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct rb4xx_nand_info *info = chip->priv;
+ unsigned char data;
+ int ret;
+
+ ret = rb4xx_cpld_read(info->spi_dev, &data, 1);
+ if (ret) {
+ pr_err("rb4xx_nand: read data failed, error %d\n", ret);
+ return 0xff;
+ }
+
+ return data;
+}
+
+static void rb4xx_nand_write_buf(struct mtd_info *mtd, const unsigned char *buf,
+ int len)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct rb4xx_nand_info *info = chip->priv;
+ int ret;
+
+ ret = rb4xx_cpld_write(info->spi_dev, buf, len);
+ if (ret)
+ pr_err("rb4xx_nand: write buf failed, error %d\n", ret);
+}
+
+static void rb4xx_nand_read_buf(struct mtd_info *mtd, unsigned char *buf,
+ int len)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct rb4xx_nand_info *info = chip->priv;
+ int ret;
+
+ ret = rb4xx_cpld_read(info->spi_dev, buf, len);
+ if (ret)
+ pr_err("rb4xx_nand: read buf failed, error %d\n", ret);
+}
+
+static int rb4xx_cpld_gpio_init(struct rb4xx_cpld *cpld, unsigned int base)
+{
+ int ret;
+
+ cpld->chip.label = "rb4xx-cpld";
+ cpld->chip.base = base;
+ cpld->chip.ngpio = CPLD_NUM_GPIOS;
+ cpld->chip.can_sleep = 1;
+ cpld->chip.dev = &cpld->spi->dev;
+ cpld->chip.get = rb4xx_cpld_gpio_get;
+ cpld->chip.set = rb4xx_cpld_gpio_set;
+ cpld->chip.direction_input = rb4xx_cpld_gpio_direction_input;
+ cpld->chip.direction_output = rb4xx_cpld_gpio_direction_output;
+
+ ret = gpiochip_add(&cpld->chip);
+ if (ret)
+ dev_err(&cpld->spi->dev, "adding GPIO chip failed, error %d\n",
+ ret);
+
+ return ret;
+}
+
+static int rb4xx_cpld_probe(struct spi_device *spi)
+{
+ struct rb4xx_cpld *cpld;
+ struct rb4xx_cpld_platform_data *pdata;
+ int ret;
+
+ pdata = dev_get_platdata(&spi->dev);
+ if (!pdata)
+ return -ENODATA;
+
+ cpld = devm_kzalloc(&spi->dev, sizeof(*cpld), GFP_KERNEL);
+ if (!cpld)
+ return -ENOMEM;
+
+ mutex_init(&cpld->lock);
+ cpld->spi = spi_dev_get(spi);
+ dev_set_drvdata(&spi->dev, cpld);
+
+ ret = spi_setup(spi);
+ if (ret) {
+ dev_err(&spi->dev, "SPI setup failed, error %d\n", ret);
+ return ret;
+ }
+
+ return rb4xx_cpld_gpio_init(cpld, pdata->gpio_base);
+}
+
+static int rb4xx_cpld_remove(struct spi_device *spi)
+{
+ struct rb4xx_cpld *cpld;
+
+ cpld = dev_get_drvdata(&spi->dev);
+ gpiochip_remove(&cpld->chip);
+ mutex_destroy(&cpld->lock);
+
+ return 0;
+}
+
+static struct spi_driver rb4xx_cpld_driver = {
+ .probe = rb4xx_cpld_probe,
+ .remove = rb4xx_cpld_remove,
+ .driver = {
+ .name = "rb4xx-cpld",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int rb4xx_nand_probe(struct platform_device *pdev)
+{
+ struct device *spi_dev;
+ struct rb4xx_nand_info *info;
+ struct rb4xx_cpld_platform_data *pdata;
+ int ret;
+
+ /*
+ * NAND chip is behind the CPLD on SPI bus 0 CS 1. Allow this
+ * to silently fail the second time around.
+ */
+ spi_register_driver(&rb4xx_cpld_driver);
+
+ /*
+ * Getting a handle on the SPI device above will fail the first time,
+ * but should succeed whenever that driver gets probed.
+ */
+ spi_dev = bus_find_device_by_name(&spi_bus_type, NULL, "spi0.1");
+ if (!spi_dev)
+ return -EPROBE_DEFER;
+
+ pdata = dev_get_platdata(spi_dev);
+ if (!pdata)
+ return -ENODATA;
+
+ info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->gpio_ale = devm_gpiod_get(&pdev->dev, "NAND ALE", GPIOD_OUT_LOW);
+ if (IS_ERR(info->gpio_ale)) {
+ dev_err(&pdev->dev, "unable to request gpio NAND ALE: %ld\n",
+ PTR_ERR(info->gpio_ale));
+ return -ENOENT;
+ }
+
+ info->gpio_cle = devm_gpiod_get(&pdev->dev, "NAND CLE", GPIOD_OUT_LOW);
+ if (IS_ERR(info->gpio_cle)) {
+ dev_err(&pdev->dev, "unable to request gpio NAND CLE: %ld\n",
+ PTR_ERR(info->gpio_cle));
+ return -ENOENT;
+ }
+
+ info->gpio_nce = devm_gpiod_get(&pdev->dev, "NAND NCE", GPIOD_OUT_LOW);
+ if (IS_ERR(info->gpio_nce)) {
+ dev_err(&pdev->dev, "unable to request gpio NAND NCE: %ld\n",
+ PTR_ERR(info->gpio_nce));
+ return -ENOENT;
+ }
+
+ /* Platform GPIO, has no device to manage it. */
+ info->gpio_rdy = gpiod_get(NULL, "NAND RDY", GPIOD_IN);
+ if (IS_ERR(info->gpio_rdy)) {
+ dev_err(&pdev->dev, "unable to request gpio RDY: %ld\n",
+ PTR_ERR(info->gpio_rdy));
+ return -ENOENT;
+ }
+
+ info->spi_dev = container_of(spi_dev, struct spi_device, dev);
+
+ info->chip.priv = info;
+ info->mtd.priv = &info->chip;
+ info->mtd.owner = THIS_MODULE;
+
+ info->chip.cmd_ctrl = rb4xx_nand_cmd_ctrl;
+ info->chip.dev_ready = rb4xx_nand_dev_ready;
+ info->chip.read_byte = rb4xx_nand_read_byte;
+ info->chip.write_buf = rb4xx_nand_write_buf;
+ info->chip.read_buf = rb4xx_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) {
+ ret = -ENXIO;
+ goto err_gpio;
+ }
+
+ if (info->mtd.writesize == 512)
+ info->chip.ecc.layout = &rb4xx_nand_ecclayout;
+
+ ret = nand_scan_tail(&info->mtd);
+ if (ret) {
+ ret = -ENXIO;
+ goto err_gpio;
+ }
+
+ ret = mtd_device_register(&info->mtd, pdata->flash_data.parts,
+ pdata->flash_data.nr_parts);
+ if (ret)
+ goto err_release_nand;
+
+ return 0;
+
+err_release_nand:
+ nand_release(&info->mtd);
+err_gpio:
+ gpiod_put(info->gpio_rdy);
+
+ return ret;
+}
+
+static int rb4xx_nand_remove(struct platform_device *pdev)
+{
+ struct rb4xx_nand_info *info = platform_get_drvdata(pdev);
+
+ nand_release(&info->mtd);
+ gpiod_put(info->gpio_rdy);
+ spi_unregister_driver(&rb4xx_cpld_driver);
+
+ return 0;
+}
+
+static struct platform_driver rb4xx_nand_driver = {
+ .probe = rb4xx_nand_probe,
+ .remove = rb4xx_nand_remove,
+ .driver = {
+ .name = "rb4xx-nand",
+ },
+};
+
+module_platform_driver(rb4xx_nand_driver);
+
+MODULE_DESCRIPTION("NAND flash driver for RouterBoard 4xx series");
+MODULE_AUTHOR("Gabor Juhos <juhosg@xxxxxxxxxxx>");
+MODULE_AUTHOR("Imre Kaloz <kaloz@xxxxxxxxxxx>");
+MODULE_AUTHOR("Bert Vermeulen <bert@xxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
1.9.1
--
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