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mtd: nand: jz4780: driver for NAND devices on JZ4780 SoCs
authorAlex Smith <alex.smith@imgtec.com>
Mon, 4 Jan 2016 12:34:43 +0000 (12:34 +0000)
committerBrian Norris <computersforpeace@gmail.com>
Thu, 7 Jan 2016 17:35:11 +0000 (09:35 -0800)
Add a driver for NAND devices connected to the NEMC on JZ4780 SoCs, as
well as the hardware BCH controller. DMA is not currently implemented.

While older 47xx SoCs also have a BCH controller, they are incompatible
with the one in the 4780 due to differing register/bit positions, which
would make implementing a common driver for them quite messy.

Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Harvey Hunt <harvey.hunt@imgtec.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
[Brian: fixed a few small mistakes]
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
drivers/mtd/nand/Kconfig
drivers/mtd/nand/Makefile
drivers/mtd/nand/jz4780_bch.c [new file with mode: 0644]
drivers/mtd/nand/jz4780_bch.h [new file with mode: 0644]
drivers/mtd/nand/jz4780_nand.c [new file with mode: 0644]

index 95b8d2b..20f01b3 100644 (file)
@@ -519,6 +519,13 @@ config MTD_NAND_JZ4740
        help
                Enables support for NAND Flash on JZ4740 SoC based boards.
 
+config MTD_NAND_JZ4780
+       tristate "Support for NAND on JZ4780 SoC"
+       depends on MACH_JZ4780 && JZ4780_NEMC
+       help
+         Enables support for NAND Flash connected to the NEMC on JZ4780 SoC
+         based boards, using the BCH controller for hardware error correction.
+
 config MTD_NAND_FSMC
        tristate "Support for NAND on ST Micros FSMC"
        depends on PLAT_SPEAR || ARCH_NOMADIK || ARCH_U8500 || MACH_U300
index 2c7f014..9e36233 100644 (file)
@@ -49,6 +49,7 @@ obj-$(CONFIG_MTD_NAND_MPC5121_NFC)    += mpc5121_nfc.o
 obj-$(CONFIG_MTD_NAND_VF610_NFC)       += vf610_nfc.o
 obj-$(CONFIG_MTD_NAND_RICOH)           += r852.o
 obj-$(CONFIG_MTD_NAND_JZ4740)          += jz4740_nand.o
+obj-$(CONFIG_MTD_NAND_JZ4780)          += jz4780_nand.o jz4780_bch.o
 obj-$(CONFIG_MTD_NAND_GPMI_NAND)       += gpmi-nand/
 obj-$(CONFIG_MTD_NAND_XWAY)            += xway_nand.o
 obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH)   += bcm47xxnflash/
diff --git a/drivers/mtd/nand/jz4780_bch.c b/drivers/mtd/nand/jz4780_bch.c
new file mode 100644 (file)
index 0000000..5954fbf
--- /dev/null
@@ -0,0 +1,381 @@
+/*
+ * JZ4780 BCH controller
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * 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/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include "jz4780_bch.h"
+
+#define BCH_BHCR                       0x0
+#define BCH_BHCCR                      0x8
+#define BCH_BHCNT                      0xc
+#define BCH_BHDR                       0x10
+#define BCH_BHPAR0                     0x14
+#define BCH_BHERR0                     0x84
+#define BCH_BHINT                      0x184
+#define BCH_BHINTES                    0x188
+#define BCH_BHINTEC                    0x18c
+#define BCH_BHINTE                     0x190
+
+#define BCH_BHCR_BSEL_SHIFT            4
+#define BCH_BHCR_BSEL_MASK             (0x7f << BCH_BHCR_BSEL_SHIFT)
+#define BCH_BHCR_ENCE                  BIT(2)
+#define BCH_BHCR_INIT                  BIT(1)
+#define BCH_BHCR_BCHE                  BIT(0)
+
+#define BCH_BHCNT_PARITYSIZE_SHIFT     16
+#define BCH_BHCNT_PARITYSIZE_MASK      (0x7f << BCH_BHCNT_PARITYSIZE_SHIFT)
+#define BCH_BHCNT_BLOCKSIZE_SHIFT      0
+#define BCH_BHCNT_BLOCKSIZE_MASK       (0x7ff << BCH_BHCNT_BLOCKSIZE_SHIFT)
+
+#define BCH_BHERR_MASK_SHIFT           16
+#define BCH_BHERR_MASK_MASK            (0xffff << BCH_BHERR_MASK_SHIFT)
+#define BCH_BHERR_INDEX_SHIFT          0
+#define BCH_BHERR_INDEX_MASK           (0x7ff << BCH_BHERR_INDEX_SHIFT)
+
+#define BCH_BHINT_ERRC_SHIFT           24
+#define BCH_BHINT_ERRC_MASK            (0x7f << BCH_BHINT_ERRC_SHIFT)
+#define BCH_BHINT_TERRC_SHIFT          16
+#define BCH_BHINT_TERRC_MASK           (0x7f << BCH_BHINT_TERRC_SHIFT)
+#define BCH_BHINT_DECF                 BIT(3)
+#define BCH_BHINT_ENCF                 BIT(2)
+#define BCH_BHINT_UNCOR                        BIT(1)
+#define BCH_BHINT_ERR                  BIT(0)
+
+#define BCH_CLK_RATE                   (200 * 1000 * 1000)
+
+/* Timeout for BCH calculation/correction. */
+#define BCH_TIMEOUT_US                 100000
+
+struct jz4780_bch {
+       struct device *dev;
+       void __iomem *base;
+       struct clk *clk;
+       struct mutex lock;
+};
+
+static void jz4780_bch_init(struct jz4780_bch *bch,
+                           struct jz4780_bch_params *params, bool encode)
+{
+       u32 reg;
+
+       /* Clear interrupt status. */
+       writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
+
+       /* Set up BCH count register. */
+       reg = params->size << BCH_BHCNT_BLOCKSIZE_SHIFT;
+       reg |= params->bytes << BCH_BHCNT_PARITYSIZE_SHIFT;
+       writel(reg, bch->base + BCH_BHCNT);
+
+       /* Initialise and enable BCH. */
+       reg = BCH_BHCR_BCHE | BCH_BHCR_INIT;
+       reg |= params->strength << BCH_BHCR_BSEL_SHIFT;
+       if (encode)
+               reg |= BCH_BHCR_ENCE;
+       writel(reg, bch->base + BCH_BHCR);
+}
+
+static void jz4780_bch_disable(struct jz4780_bch *bch)
+{
+       writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
+       writel(BCH_BHCR_BCHE, bch->base + BCH_BHCCR);
+}
+
+static void jz4780_bch_write_data(struct jz4780_bch *bch, const void *buf,
+                                 size_t size)
+{
+       size_t size32 = size / sizeof(u32);
+       size_t size8 = size % sizeof(u32);
+       const u32 *src32;
+       const u8 *src8;
+
+       src32 = (const u32 *)buf;
+       while (size32--)
+               writel(*src32++, bch->base + BCH_BHDR);
+
+       src8 = (const u8 *)src32;
+       while (size8--)
+               writeb(*src8++, bch->base + BCH_BHDR);
+}
+
+static void jz4780_bch_read_parity(struct jz4780_bch *bch, void *buf,
+                                  size_t size)
+{
+       size_t size32 = size / sizeof(u32);
+       size_t size8 = size % sizeof(u32);
+       u32 *dest32;
+       u8 *dest8;
+       u32 val, offset = 0;
+
+       dest32 = (u32 *)buf;
+       while (size32--) {
+               *dest32++ = readl(bch->base + BCH_BHPAR0 + offset);
+               offset += sizeof(u32);
+       }
+
+       dest8 = (u8 *)dest32;
+       val = readl(bch->base + BCH_BHPAR0 + offset);
+       switch (size8) {
+       case 3:
+               dest8[2] = (val >> 16) & 0xff;
+       case 2:
+               dest8[1] = (val >> 8) & 0xff;
+       case 1:
+               dest8[0] = val & 0xff;
+               break;
+       }
+}
+
+static bool jz4780_bch_wait_complete(struct jz4780_bch *bch, unsigned int irq,
+                                    u32 *status)
+{
+       u32 reg;
+       int ret;
+
+       /*
+        * While we could use interrupts here and sleep until the operation
+        * completes, the controller works fairly quickly (usually a few
+        * microseconds) and so the overhead of sleeping until we get an
+        * interrupt quite noticeably decreases performance.
+        */
+       ret = readl_poll_timeout(bch->base + BCH_BHINT, reg,
+                                (reg & irq) == irq, 0, BCH_TIMEOUT_US);
+       if (ret)
+               return false;
+
+       if (status)
+               *status = reg;
+
+       writel(reg, bch->base + BCH_BHINT);
+       return true;
+}
+
+/**
+ * jz4780_bch_calculate() - calculate ECC for a data buffer
+ * @bch: BCH device.
+ * @params: BCH parameters.
+ * @buf: input buffer with raw data.
+ * @ecc_code: output buffer with ECC.
+ *
+ * Return: 0 on success, -ETIMEDOUT if timed out while waiting for BCH
+ * controller.
+ */
+int jz4780_bch_calculate(struct jz4780_bch *bch, struct jz4780_bch_params *params,
+                        const u8 *buf, u8 *ecc_code)
+{
+       int ret = 0;
+
+       mutex_lock(&bch->lock);
+       jz4780_bch_init(bch, params, true);
+       jz4780_bch_write_data(bch, buf, params->size);
+
+       if (jz4780_bch_wait_complete(bch, BCH_BHINT_ENCF, NULL)) {
+               jz4780_bch_read_parity(bch, ecc_code, params->bytes);
+       } else {
+               dev_err(bch->dev, "timed out while calculating ECC\n");
+               ret = -ETIMEDOUT;
+       }
+
+       jz4780_bch_disable(bch);
+       mutex_unlock(&bch->lock);
+       return ret;
+}
+EXPORT_SYMBOL(jz4780_bch_calculate);
+
+/**
+ * jz4780_bch_correct() - detect and correct bit errors
+ * @bch: BCH device.
+ * @params: BCH parameters.
+ * @buf: raw data read from the chip.
+ * @ecc_code: ECC read from the chip.
+ *
+ * Given the raw data and the ECC read from the NAND device, detects and
+ * corrects errors in the data.
+ *
+ * Return: the number of bit errors corrected, or -1 if there are too many
+ * errors to correct or we timed out waiting for the controller.
+ */
+int jz4780_bch_correct(struct jz4780_bch *bch, struct jz4780_bch_params *params,
+                      u8 *buf, u8 *ecc_code)
+{
+       u32 reg, mask, index;
+       int i, ret, count;
+
+       mutex_lock(&bch->lock);
+
+       jz4780_bch_init(bch, params, false);
+       jz4780_bch_write_data(bch, buf, params->size);
+       jz4780_bch_write_data(bch, ecc_code, params->bytes);
+
+       if (!jz4780_bch_wait_complete(bch, BCH_BHINT_DECF, &reg)) {
+               dev_err(bch->dev, "timed out while correcting data\n");
+               ret = -1;
+               goto out;
+       }
+
+       if (reg & BCH_BHINT_UNCOR) {
+               dev_warn(bch->dev, "uncorrectable ECC error\n");
+               ret = -1;
+               goto out;
+       }
+
+       /* Correct any detected errors. */
+       if (reg & BCH_BHINT_ERR) {
+               count = (reg & BCH_BHINT_ERRC_MASK) >> BCH_BHINT_ERRC_SHIFT;
+               ret = (reg & BCH_BHINT_TERRC_MASK) >> BCH_BHINT_TERRC_SHIFT;
+
+               for (i = 0; i < count; i++) {
+                       reg = readl(bch->base + BCH_BHERR0 + (i * 4));
+                       mask = (reg & BCH_BHERR_MASK_MASK) >>
+                                               BCH_BHERR_MASK_SHIFT;
+                       index = (reg & BCH_BHERR_INDEX_MASK) >>
+                                               BCH_BHERR_INDEX_SHIFT;
+                       buf[(index * 2) + 0] ^= mask;
+                       buf[(index * 2) + 1] ^= mask >> 8;
+               }
+       } else {
+               ret = 0;
+       }
+
+out:
+       jz4780_bch_disable(bch);
+       mutex_unlock(&bch->lock);
+       return ret;
+}
+EXPORT_SYMBOL(jz4780_bch_correct);
+
+/**
+ * jz4780_bch_get() - get the BCH controller device
+ * @np: BCH device tree node.
+ *
+ * Gets the BCH controller device from the specified device tree node. The
+ * device must be released with jz4780_bch_release() when it is no longer being
+ * used.
+ *
+ * Return: a pointer to jz4780_bch, errors are encoded into the pointer.
+ * PTR_ERR(-EPROBE_DEFER) if the device hasn't been initialised yet.
+ */
+static struct jz4780_bch *jz4780_bch_get(struct device_node *np)
+{
+       struct platform_device *pdev;
+       struct jz4780_bch *bch;
+
+       pdev = of_find_device_by_node(np);
+       if (!pdev || !platform_get_drvdata(pdev))
+               return ERR_PTR(-EPROBE_DEFER);
+
+       get_device(&pdev->dev);
+
+       bch = platform_get_drvdata(pdev);
+       clk_prepare_enable(bch->clk);
+
+       bch->dev = &pdev->dev;
+       return bch;
+}
+
+/**
+ * of_jz4780_bch_get() - get the BCH controller from a DT node
+ * @of_node: the node that contains a bch-controller property.
+ *
+ * Get the bch-controller property from the given device tree
+ * node and pass it to jz4780_bch_get to do the work.
+ *
+ * Return: a pointer to jz4780_bch, errors are encoded into the pointer.
+ * PTR_ERR(-EPROBE_DEFER) if the device hasn't been initialised yet.
+ */
+struct jz4780_bch *of_jz4780_bch_get(struct device_node *of_node)
+{
+       struct jz4780_bch *bch = NULL;
+       struct device_node *np;
+
+       np = of_parse_phandle(of_node, "ingenic,bch-controller", 0);
+
+       if (np) {
+               bch = jz4780_bch_get(np);
+               of_node_put(np);
+       }
+       return bch;
+}
+EXPORT_SYMBOL(of_jz4780_bch_get);
+
+/**
+ * jz4780_bch_release() - release the BCH controller device
+ * @bch: BCH device.
+ */
+void jz4780_bch_release(struct jz4780_bch *bch)
+{
+       clk_disable_unprepare(bch->clk);
+       put_device(bch->dev);
+}
+EXPORT_SYMBOL(jz4780_bch_release);
+
+static int jz4780_bch_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct jz4780_bch *bch;
+       struct resource *res;
+
+       bch = devm_kzalloc(dev, sizeof(*bch), GFP_KERNEL);
+       if (!bch)
+               return -ENOMEM;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       bch->base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(bch->base))
+               return PTR_ERR(bch->base);
+
+       jz4780_bch_disable(bch);
+
+       bch->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(bch->clk)) {
+               dev_err(dev, "failed to get clock: %ld\n", PTR_ERR(bch->clk));
+               return PTR_ERR(bch->clk);
+       }
+
+       clk_set_rate(bch->clk, BCH_CLK_RATE);
+
+       mutex_init(&bch->lock);
+
+       bch->dev = dev;
+       platform_set_drvdata(pdev, bch);
+
+       return 0;
+}
+
+static const struct of_device_id jz4780_bch_dt_match[] = {
+       { .compatible = "ingenic,jz4780-bch" },
+       {},
+};
+MODULE_DEVICE_TABLE(of, jz4780_bch_dt_match);
+
+static struct platform_driver jz4780_bch_driver = {
+       .probe          = jz4780_bch_probe,
+       .driver = {
+               .name   = "jz4780-bch",
+               .of_match_table = of_match_ptr(jz4780_bch_dt_match),
+       },
+};
+module_platform_driver(jz4780_bch_driver);
+
+MODULE_AUTHOR("Alex Smith <alex@alex-smith.me.uk>");
+MODULE_AUTHOR("Harvey Hunt <harvey.hunt@imgtec.com>");
+MODULE_DESCRIPTION("Ingenic JZ4780 BCH error correction driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/mtd/nand/jz4780_bch.h b/drivers/mtd/nand/jz4780_bch.h
new file mode 100644 (file)
index 0000000..bf47180
--- /dev/null
@@ -0,0 +1,43 @@
+/*
+ * JZ4780 BCH controller
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * 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 __DRIVERS_MTD_NAND_JZ4780_BCH_H__
+#define __DRIVERS_MTD_NAND_JZ4780_BCH_H__
+
+#include <linux/types.h>
+
+struct device;
+struct device_node;
+struct jz4780_bch;
+
+/**
+ * struct jz4780_bch_params - BCH parameters
+ * @size: data bytes per ECC step.
+ * @bytes: ECC bytes per step.
+ * @strength: number of correctable bits per ECC step.
+ */
+struct jz4780_bch_params {
+       int size;
+       int bytes;
+       int strength;
+};
+
+int jz4780_bch_calculate(struct jz4780_bch *bch,
+                               struct jz4780_bch_params *params,
+                               const u8 *buf, u8 *ecc_code);
+int jz4780_bch_correct(struct jz4780_bch *bch,
+                             struct jz4780_bch_params *params, u8 *buf,
+                             u8 *ecc_code);
+
+void jz4780_bch_release(struct jz4780_bch *bch);
+struct jz4780_bch *of_jz4780_bch_get(struct device_node *np);
+
+#endif /* __DRIVERS_MTD_NAND_JZ4780_BCH_H__ */
diff --git a/drivers/mtd/nand/jz4780_nand.c b/drivers/mtd/nand/jz4780_nand.c
new file mode 100644 (file)
index 0000000..17eb9f2
--- /dev/null
@@ -0,0 +1,425 @@
+/*
+ * JZ4780 NAND driver
+ *
+ * Copyright (c) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * 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/delay.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/gpio/consumer.h>
+#include <linux/of_mtd.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+#include <linux/jz4780-nemc.h>
+
+#include "jz4780_bch.h"
+
+#define DRV_NAME       "jz4780-nand"
+
+#define OFFSET_DATA    0x00000000
+#define OFFSET_CMD     0x00400000
+#define OFFSET_ADDR    0x00800000
+
+/* Command delay when there is no R/B pin. */
+#define RB_DELAY_US    100
+
+struct jz4780_nand_cs {
+       unsigned int bank;
+       void __iomem *base;
+};
+
+struct jz4780_nand_controller {
+       struct device *dev;
+       struct jz4780_bch *bch;
+       struct nand_hw_control controller;
+       unsigned int num_banks;
+       struct list_head chips;
+       int selected;
+       struct jz4780_nand_cs cs[];
+};
+
+struct jz4780_nand_chip {
+       struct nand_chip chip;
+       struct list_head chip_list;
+
+       struct nand_ecclayout ecclayout;
+
+       struct gpio_desc *busy_gpio;
+       struct gpio_desc *wp_gpio;
+       unsigned int reading: 1;
+};
+
+static inline struct jz4780_nand_chip *to_jz4780_nand_chip(struct mtd_info *mtd)
+{
+       return container_of(mtd_to_nand(mtd), struct jz4780_nand_chip, chip);
+}
+
+static inline struct jz4780_nand_controller *to_jz4780_nand_controller(struct nand_hw_control *ctrl)
+{
+       return container_of(ctrl, struct jz4780_nand_controller, controller);
+}
+
+static void jz4780_nand_select_chip(struct mtd_info *mtd, int chipnr)
+{
+       struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+       struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);
+       struct jz4780_nand_cs *cs;
+
+       /* Ensure the currently selected chip is deasserted. */
+       if (chipnr == -1 && nfc->selected >= 0) {
+               cs = &nfc->cs[nfc->selected];
+               jz4780_nemc_assert(nfc->dev, cs->bank, false);
+       }
+
+       nfc->selected = chipnr;
+}
+
+static void jz4780_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
+                                unsigned int ctrl)
+{
+       struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+       struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);
+       struct jz4780_nand_cs *cs;
+
+       if (WARN_ON(nfc->selected < 0))
+               return;
+
+       cs = &nfc->cs[nfc->selected];
+
+       jz4780_nemc_assert(nfc->dev, cs->bank, ctrl & NAND_NCE);
+
+       if (cmd == NAND_CMD_NONE)
+               return;
+
+       if (ctrl & NAND_ALE)
+               writeb(cmd, cs->base + OFFSET_ADDR);
+       else if (ctrl & NAND_CLE)
+               writeb(cmd, cs->base + OFFSET_CMD);
+}
+
+static int jz4780_nand_dev_ready(struct mtd_info *mtd)
+{
+       struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+
+       return !gpiod_get_value_cansleep(nand->busy_gpio);
+}
+
+static void jz4780_nand_ecc_hwctl(struct mtd_info *mtd, int mode)
+{
+       struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+
+       nand->reading = (mode == NAND_ECC_READ);
+}
+
+static int jz4780_nand_ecc_calculate(struct mtd_info *mtd, const u8 *dat,
+                                    u8 *ecc_code)
+{
+       struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+       struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);
+       struct jz4780_bch_params params;
+
+       /*
+        * Don't need to generate the ECC when reading, BCH does it for us as
+        * part of decoding/correction.
+        */
+       if (nand->reading)
+               return 0;
+
+       params.size = nand->chip.ecc.size;
+       params.bytes = nand->chip.ecc.bytes;
+       params.strength = nand->chip.ecc.strength;
+
+       return jz4780_bch_calculate(nfc->bch, &params, dat, ecc_code);
+}
+
+static int jz4780_nand_ecc_correct(struct mtd_info *mtd, u8 *dat,
+                                  u8 *read_ecc, u8 *calc_ecc)
+{
+       struct jz4780_nand_chip *nand = to_jz4780_nand_chip(mtd);
+       struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(nand->chip.controller);
+       struct jz4780_bch_params params;
+
+       params.size = nand->chip.ecc.size;
+       params.bytes = nand->chip.ecc.bytes;
+       params.strength = nand->chip.ecc.strength;
+
+       return jz4780_bch_correct(nfc->bch, &params, dat, read_ecc);
+}
+
+static int jz4780_nand_init_ecc(struct jz4780_nand_chip *nand, struct device *dev)
+{
+       struct nand_chip *chip = &nand->chip;
+       struct mtd_info *mtd = nand_to_mtd(chip);
+       struct jz4780_nand_controller *nfc = to_jz4780_nand_controller(chip->controller);
+       struct nand_ecclayout *layout = &nand->ecclayout;
+       u32 start, i;
+
+       chip->ecc.bytes = fls((1 + 8) * chip->ecc.size) *
+                               (chip->ecc.strength / 8);
+
+       if (nfc->bch && chip->ecc.mode == NAND_ECC_HW) {
+               chip->ecc.hwctl = jz4780_nand_ecc_hwctl;
+               chip->ecc.calculate = jz4780_nand_ecc_calculate;
+               chip->ecc.correct = jz4780_nand_ecc_correct;
+       } else if (!nfc->bch && chip->ecc.mode == NAND_ECC_HW) {
+               dev_err(dev, "HW BCH selected, but BCH controller not found\n");
+               return -ENODEV;
+       }
+
+       if (chip->ecc.mode == NAND_ECC_HW_SYNDROME) {
+               dev_err(dev, "ECC HW syndrome not supported\n");
+               return -EINVAL;
+       }
+
+       if (chip->ecc.mode != NAND_ECC_NONE)
+               dev_info(dev, "using %s (strength %d, size %d, bytes %d)\n",
+                       (nfc->bch) ? "hardware BCH" : "software ECC",
+                       chip->ecc.strength, chip->ecc.size, chip->ecc.bytes);
+       else
+               dev_info(dev, "not using ECC\n");
+
+       /* The NAND core will generate the ECC layout. */
+       if (chip->ecc.mode == NAND_ECC_SOFT || chip->ecc.mode == NAND_ECC_SOFT_BCH)
+               return 0;
+
+       /* Generate ECC layout. ECC codes are right aligned in the OOB area. */
+       layout->eccbytes = mtd->writesize / chip->ecc.size * chip->ecc.bytes;
+
+       if (layout->eccbytes > mtd->oobsize - 2) {
+               dev_err(dev,
+                       "invalid ECC config: required %d ECC bytes, but only %d are available",
+                       layout->eccbytes, mtd->oobsize - 2);
+               return -EINVAL;
+       }
+
+       start = mtd->oobsize - layout->eccbytes;
+       for (i = 0; i < layout->eccbytes; i++)
+               layout->eccpos[i] = start + i;
+
+       layout->oobfree[0].offset = 2;
+       layout->oobfree[0].length = mtd->oobsize - layout->eccbytes - 2;
+
+       chip->ecc.layout = layout;
+       return 0;
+}
+
+static int jz4780_nand_init_chip(struct platform_device *pdev,
+                               struct jz4780_nand_controller *nfc,
+                               struct device_node *np,
+                               unsigned int chipnr)
+{
+       struct device *dev = &pdev->dev;
+       struct jz4780_nand_chip *nand;
+       struct jz4780_nand_cs *cs;
+       struct resource *res;
+       struct nand_chip *chip;
+       struct mtd_info *mtd;
+       const __be32 *reg;
+       int ret = 0;
+
+       cs = &nfc->cs[chipnr];
+
+       reg = of_get_property(np, "reg", NULL);
+       if (!reg)
+               return -EINVAL;
+
+       cs->bank = be32_to_cpu(*reg);
+
+       jz4780_nemc_set_type(nfc->dev, cs->bank, JZ4780_NEMC_BANK_NAND);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, chipnr);
+       cs->base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(cs->base))
+               return PTR_ERR(cs->base);
+
+       nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
+       if (!nand)
+               return -ENOMEM;
+
+       nand->busy_gpio = devm_gpiod_get_optional(dev, "rb", GPIOD_IN);
+
+       if (IS_ERR(nand->busy_gpio)) {
+               ret = PTR_ERR(nand->busy_gpio);
+               dev_err(dev, "failed to request busy GPIO: %d\n", ret);
+               return ret;
+       } else if (nand->busy_gpio) {
+               nand->chip.dev_ready = jz4780_nand_dev_ready;
+       }
+
+       nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
+
+       if (IS_ERR(nand->wp_gpio)) {
+               ret = PTR_ERR(nand->wp_gpio);
+               dev_err(dev, "failed to request WP GPIO: %d\n", ret);
+               return ret;
+       }
+
+       chip = &nand->chip;
+       mtd = nand_to_mtd(chip);
+       mtd->priv = chip;
+       mtd->name = devm_kasprintf(dev, GFP_KERNEL, "%s.%d", dev_name(dev),
+                                  cs->bank);
+       if (!mtd->name)
+               return -ENOMEM;
+       mtd->dev.parent = dev;
+
+       chip->IO_ADDR_R = cs->base + OFFSET_DATA;
+       chip->IO_ADDR_W = cs->base + OFFSET_DATA;
+       chip->chip_delay = RB_DELAY_US;
+       chip->options = NAND_NO_SUBPAGE_WRITE;
+       chip->select_chip = jz4780_nand_select_chip;
+       chip->cmd_ctrl = jz4780_nand_cmd_ctrl;
+       chip->ecc.mode = NAND_ECC_HW;
+       chip->controller = &nfc->controller;
+       nand_set_flash_node(chip, np);
+
+       ret = nand_scan_ident(mtd, 1, NULL);
+       if (ret)
+               return ret;
+
+       ret = jz4780_nand_init_ecc(nand, dev);
+       if (ret)
+               return ret;
+
+       ret = nand_scan_tail(mtd);
+       if (ret)
+               return ret;
+
+       ret = mtd_device_register(mtd, NULL, 0);
+       if (ret) {
+               nand_release(mtd);
+               return ret;
+       }
+
+       list_add_tail(&nand->chip_list, &nfc->chips);
+
+       return 0;
+}
+
+static void jz4780_nand_cleanup_chips(struct jz4780_nand_controller *nfc)
+{
+       struct jz4780_nand_chip *chip;
+
+       while (!list_empty(&nfc->chips)) {
+               chip = list_first_entry(&nfc->chips, struct jz4780_nand_chip, chip_list);
+               nand_release(nand_to_mtd(&chip->chip));
+               list_del(&chip->chip_list);
+       }
+}
+
+static int jz4780_nand_init_chips(struct jz4780_nand_controller *nfc,
+                                 struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *np;
+       int i = 0;
+       int ret;
+       int num_chips = of_get_child_count(dev->of_node);
+
+       if (num_chips > nfc->num_banks) {
+               dev_err(dev, "found %d chips but only %d banks\n", num_chips, nfc->num_banks);
+               return -EINVAL;
+       }
+
+       for_each_child_of_node(dev->of_node, np) {
+               ret = jz4780_nand_init_chip(pdev, nfc, np, i);
+               if (ret) {
+                       jz4780_nand_cleanup_chips(nfc);
+                       return ret;
+               }
+
+               i++;
+       }
+
+       return 0;
+}
+
+static int jz4780_nand_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       unsigned int num_banks;
+       struct jz4780_nand_controller *nfc;
+       int ret;
+
+       num_banks = jz4780_nemc_num_banks(dev);
+       if (num_banks == 0) {
+               dev_err(dev, "no banks found\n");
+               return -ENODEV;
+       }
+
+       nfc = devm_kzalloc(dev, sizeof(*nfc) + (sizeof(nfc->cs[0]) * num_banks), GFP_KERNEL);
+       if (!nfc)
+               return -ENOMEM;
+
+       /*
+        * Check for BCH HW before we call nand_scan_ident, to prevent us from
+        * having to call it again if the BCH driver returns -EPROBE_DEFER.
+        */
+       nfc->bch = of_jz4780_bch_get(dev->of_node);
+       if (IS_ERR(nfc->bch))
+               return PTR_ERR(nfc->bch);
+
+       nfc->dev = dev;
+       nfc->num_banks = num_banks;
+
+       spin_lock_init(&nfc->controller.lock);
+       INIT_LIST_HEAD(&nfc->chips);
+       init_waitqueue_head(&nfc->controller.wq);
+
+       ret = jz4780_nand_init_chips(nfc, pdev);
+       if (ret) {
+               if (nfc->bch)
+                       jz4780_bch_release(nfc->bch);
+               return ret;
+       }
+
+       platform_set_drvdata(pdev, nfc);
+       return 0;
+}
+
+static int jz4780_nand_remove(struct platform_device *pdev)
+{
+       struct jz4780_nand_controller *nfc = platform_get_drvdata(pdev);
+
+       if (nfc->bch)
+               jz4780_bch_release(nfc->bch);
+
+       jz4780_nand_cleanup_chips(nfc);
+
+       return 0;
+}
+
+static const struct of_device_id jz4780_nand_dt_match[] = {
+       { .compatible = "ingenic,jz4780-nand" },
+       {},
+};
+MODULE_DEVICE_TABLE(of, jz4780_nand_dt_match);
+
+static struct platform_driver jz4780_nand_driver = {
+       .probe          = jz4780_nand_probe,
+       .remove         = jz4780_nand_remove,
+       .driver = {
+               .name   = DRV_NAME,
+               .of_match_table = of_match_ptr(jz4780_nand_dt_match),
+       },
+};
+module_platform_driver(jz4780_nand_driver);
+
+MODULE_AUTHOR("Alex Smith <alex@alex-smith.me.uk>");
+MODULE_AUTHOR("Harvey Hunt <harvey.hunt@imgtec.com>");
+MODULE_DESCRIPTION("Ingenic JZ4780 NAND driver");
+MODULE_LICENSE("GPL v2");