The boot ROM of the JZ4725B SoC expects a specific OOB layout on the
NAND, so we use it unconditionally in the ingenic-nand driver.

Also add the jz4725b-bch driver to support the JZ4725B-specific BCH
hardware.

Signed-off-by: Paul Cercueil <p...@crapouillou.net>
---

Changes:

v2: Instead of forcing the OOB layout, leave it to the board code or
    devicetree to decide if the jz4725b-specific layout should be used
    or not.

v3: - Revert the change in v2, as the previous behaviour was correct.
    - Also add support for the hardware BCH of the JZ4725B in this
      patch.

v4: - Add MODULE_* macros
    - Add tweaks suggested by upstream feedback

 drivers/mtd/nand/raw/ingenic/Kconfig        |  10 +
 drivers/mtd/nand/raw/ingenic/Makefile       |   1 +
 drivers/mtd/nand/raw/ingenic/ingenic_nand.c |  48 ++++-
 drivers/mtd/nand/raw/ingenic/jz4725b_bch.c  | 292 ++++++++++++++++++++++++++++
 4 files changed, 350 insertions(+), 1 deletion(-)
 create mode 100644 drivers/mtd/nand/raw/ingenic/jz4725b_bch.c

diff --git a/drivers/mtd/nand/raw/ingenic/Kconfig 
b/drivers/mtd/nand/raw/ingenic/Kconfig
index cc663cc15119..497b46b144f2 100644
--- a/drivers/mtd/nand/raw/ingenic/Kconfig
+++ b/drivers/mtd/nand/raw/ingenic/Kconfig
@@ -27,6 +27,16 @@ config MTD_NAND_JZ4740_ECC
          This driver can also be built as a module. If so, the module
          will be called jz4740-ecc.
 
+config MTD_NAND_JZ4725B_BCH
+       tristate "Hardware BCH support for JZ4725B SoC"
+       select MTD_NAND_INGENIC_ECC
+       help
+         Enable this driver to support the BCH error-correction hardware
+         present on the JZ4725B SoC from Ingenic.
+
+         This driver can also be built as a module. If so, the module
+         will be called jz4725b-bch.
+
 config MTD_NAND_JZ4780_BCH
        tristate "Hardware BCH support for JZ4780 SoC"
        select MTD_NAND_INGENIC_ECC
diff --git a/drivers/mtd/nand/raw/ingenic/Makefile 
b/drivers/mtd/nand/raw/ingenic/Makefile
index 563b7effcf59..ab2c5f47e5b7 100644
--- a/drivers/mtd/nand/raw/ingenic/Makefile
+++ b/drivers/mtd/nand/raw/ingenic/Makefile
@@ -3,4 +3,5 @@ obj-$(CONFIG_MTD_NAND_JZ4780) += ingenic_nand.o
 
 obj-$(CONFIG_MTD_NAND_INGENIC_ECC) += ingenic_ecc.o
 obj-$(CONFIG_MTD_NAND_JZ4740_ECC) += jz4740_ecc.o
+obj-$(CONFIG_MTD_NAND_JZ4725B_BCH) += jz4725b_bch.o
 obj-$(CONFIG_MTD_NAND_JZ4780_BCH) += jz4780_bch.o
diff --git a/drivers/mtd/nand/raw/ingenic/ingenic_nand.c 
b/drivers/mtd/nand/raw/ingenic/ingenic_nand.c
index 036938fdad51..4837bbce7099 100644
--- a/drivers/mtd/nand/raw/ingenic/ingenic_nand.c
+++ b/drivers/mtd/nand/raw/ingenic/ingenic_nand.c
@@ -34,6 +34,7 @@ struct jz_soc_info {
        unsigned long data_offset;
        unsigned long addr_offset;
        unsigned long cmd_offset;
+       const struct mtd_ooblayout_ops *oob_layout;
 };
 
 struct ingenic_nand_cs {
@@ -71,6 +72,41 @@ static inline struct ingenic_nfc *to_ingenic_nfc(struct 
nand_controller *ctrl)
        return container_of(ctrl, struct ingenic_nfc, controller);
 }
 
+static int jz4725b_ooblayout_ecc(struct mtd_info *mtd, int section,
+                                struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+       if (section || !ecc->total)
+               return -ERANGE;
+
+       oobregion->length = ecc->total;
+       oobregion->offset = 3;
+
+       return 0;
+}
+
+static int jz4725b_ooblayout_free(struct mtd_info *mtd, int section,
+                                 struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+       if (section)
+               return -ERANGE;
+
+       oobregion->length = mtd->oobsize - ecc->total - 3;
+       oobregion->offset = 3 + ecc->total;
+
+       return 0;
+}
+
+const struct mtd_ooblayout_ops jz4725b_ooblayout_ops = {
+       .ecc = jz4725b_ooblayout_ecc,
+       .free = jz4725b_ooblayout_free,
+};
+
 static void ingenic_nand_select_chip(struct nand_chip *chip, int chipnr)
 {
        struct ingenic_nand *nand = to_ingenic_nand(nand_to_mtd(chip));
@@ -211,7 +247,7 @@ static int ingenic_nand_attach_chip(struct nand_chip *chip)
                return -EINVAL;
        }
 
-       mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
+       mtd_set_ooblayout(mtd, nfc->soc_info->oob_layout);
 
        return 0;
 }
@@ -407,16 +443,26 @@ static const struct jz_soc_info jz4740_soc_info = {
        .data_offset = 0x00000000,
        .cmd_offset = 0x00008000,
        .addr_offset = 0x00010000,
+       .oob_layout = &nand_ooblayout_lp_ops,
+};
+
+static const struct jz_soc_info jz4725b_soc_info = {
+       .data_offset = 0x00000000,
+       .cmd_offset = 0x00008000,
+       .addr_offset = 0x00010000,
+       .oob_layout = &jz4725b_ooblayout_ops,
 };
 
 static const struct jz_soc_info jz4780_soc_info = {
        .data_offset = 0x00000000,
        .cmd_offset = 0x00400000,
        .addr_offset = 0x00800000,
+       .oob_layout = &nand_ooblayout_lp_ops,
 };
 
 static const struct of_device_id ingenic_nand_dt_match[] = {
        { .compatible = "ingenic,jz4740-nand", .data = &jz4740_soc_info },
+       { .compatible = "ingenic,jz4725b-nand", .data = &jz4725b_soc_info },
        { .compatible = "ingenic,jz4780-nand", .data = &jz4780_soc_info },
        {},
 };
diff --git a/drivers/mtd/nand/raw/ingenic/jz4725b_bch.c 
b/drivers/mtd/nand/raw/ingenic/jz4725b_bch.c
new file mode 100644
index 000000000000..f7094c34b5df
--- /dev/null
+++ b/drivers/mtd/nand/raw/ingenic/jz4725b_bch.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * JZ4725B BCH controller driver
+ *
+ * Copyright (C) 2019 Paul Cercueil <p...@crapouillou.net>
+ *
+ * Based on jz4780_bch.c
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include "ingenic_ecc.h"
+
+#define BCH_BHCR                       0x0
+#define BCH_BHCSR                      0x4
+#define BCH_BHCCR                      0x8
+#define BCH_BHCNT                      0xc
+#define BCH_BHDR                       0x10
+#define BCH_BHPAR0                     0x14
+#define BCH_BHERR0                     0x28
+#define BCH_BHINT                      0x24
+#define BCH_BHINTES                    0x3c
+#define BCH_BHINTEC                    0x40
+#define BCH_BHINTE                     0x38
+
+#define BCH_BHCR_ENCE                  BIT(3)
+#define BCH_BHCR_BSEL                  BIT(2)
+#define BCH_BHCR_INIT                  BIT(1)
+#define BCH_BHCR_BCHE                  BIT(0)
+
+#define BCH_BHCNT_DEC_COUNT_SHIFT      16
+#define BCH_BHCNT_DEC_COUNT_MASK       (0x3ff << BCH_BHCNT_DEC_COUNT_SHIFT)
+#define BCH_BHCNT_ENC_COUNT_SHIFT      0
+#define BCH_BHCNT_ENC_COUNT_MASK       (0x3ff << BCH_BHCNT_ENC_COUNT_SHIFT)
+
+#define BCH_BHERR_INDEX0_SHIFT         0
+#define BCH_BHERR_INDEX0_MASK          (0x1fff << BCH_BHERR_INDEX0_SHIFT)
+#define BCH_BHERR_INDEX1_SHIFT         16
+#define BCH_BHERR_INDEX1_MASK          (0x1fff << BCH_BHERR_INDEX1_SHIFT)
+
+#define BCH_BHINT_ERRC_SHIFT           28
+#define BCH_BHINT_ERRC_MASK            (0xf << BCH_BHINT_ERRC_SHIFT)
+#define BCH_BHINT_TERRC_SHIFT          16
+#define BCH_BHINT_TERRC_MASK           (0x7f << BCH_BHINT_TERRC_SHIFT)
+#define BCH_BHINT_ALL_0                        BIT(5)
+#define BCH_BHINT_ALL_F                        BIT(4)
+#define BCH_BHINT_DECF                 BIT(3)
+#define BCH_BHINT_ENCF                 BIT(2)
+#define BCH_BHINT_UNCOR                        BIT(1)
+#define BCH_BHINT_ERR                  BIT(0)
+
+/* Timeout for BCH calculation/correction. */
+#define BCH_TIMEOUT_US                 100000
+
+static inline void jz4725b_bch_config_set(struct ingenic_ecc *bch, u32 cfg)
+{
+       writel(cfg, bch->base + BCH_BHCSR);
+}
+
+static inline void jz4725b_bch_config_clear(struct ingenic_ecc *bch, u32 cfg)
+{
+       writel(cfg, bch->base + BCH_BHCCR);
+}
+
+static int jz4725b_bch_init(struct ingenic_ecc *bch,
+                           struct ingenic_ecc_params *params, bool calc_ecc)
+{
+       u32 reg, max_value;
+
+       /* Clear interrupt status. */
+       writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
+
+       /* Initialise and enable BCH. */
+       jz4725b_bch_config_clear(bch, 0x1f);
+       jz4725b_bch_config_set(bch, BCH_BHCR_BCHE);
+
+       if (params->strength == 8)
+               jz4725b_bch_config_set(bch, BCH_BHCR_BSEL);
+       else
+               jz4725b_bch_config_clear(bch, BCH_BHCR_BSEL);
+
+       if (calc_ecc) /* calculate ECC from data */
+               jz4725b_bch_config_set(bch, BCH_BHCR_ENCE);
+       else /* correct data from ECC */
+               jz4725b_bch_config_clear(bch, BCH_BHCR_ENCE);
+
+       jz4725b_bch_config_set(bch, BCH_BHCR_INIT);
+
+       max_value = BCH_BHCNT_ENC_COUNT_MASK >> BCH_BHCNT_ENC_COUNT_SHIFT;
+       if (params->size > max_value)
+               return -EINVAL;
+
+       max_value = BCH_BHCNT_DEC_COUNT_MASK >> BCH_BHCNT_DEC_COUNT_SHIFT;
+       if (params->size + params->bytes > max_value)
+               return -EINVAL;
+
+       /* Set up BCH count register. */
+       reg = params->size << BCH_BHCNT_ENC_COUNT_SHIFT;
+       reg |= (params->size + params->bytes) << BCH_BHCNT_DEC_COUNT_SHIFT;
+       writel(reg, bch->base + BCH_BHCNT);
+
+       return 0;
+}
+
+static void jz4725b_bch_disable(struct ingenic_ecc *bch)
+{
+       /* Clear interrupts */
+       writel(readl(bch->base + BCH_BHINT), bch->base + BCH_BHINT);
+
+       /* Disable the hardware */
+       jz4725b_bch_config_clear(bch, BCH_BHCR_BCHE);
+}
+
+static void jz4725b_bch_write_data(struct ingenic_ecc *bch, const u8 *buf,
+                                  size_t size)
+{
+       while (size--)
+               writeb(*buf++, bch->base + BCH_BHDR);
+}
+
+static void jz4725b_bch_read_parity(struct ingenic_ecc *bch, u8 *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_relaxed(bch->base + BCH_BHPAR0 + offset);
+               offset += sizeof(u32);
+       }
+
+       dest8 = (u8 *)dest32;
+       val = readl_relaxed(bch->base + BCH_BHPAR0 + offset);
+       switch (size8) {
+       case 3:
+               dest8[2] = (val >> 16) & 0xff;
+       case 2: /* fall-through */
+               dest8[1] = (val >> 8) & 0xff;
+       case 1: /* fall-through */
+               dest8[0] = val & 0xff;
+               break;
+       }
+}
+
+static int jz4725b_bch_wait_complete(struct ingenic_ecc *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_relaxed_poll_timeout(bch->base + BCH_BHINT, reg,
+                                        reg & irq, 0, BCH_TIMEOUT_US);
+       if (ret)
+               return ret;
+
+       if (status)
+               *status = reg;
+
+       writel(reg, bch->base + BCH_BHINT);
+
+       return 0;
+}
+
+static int jz4725b_calculate(struct ingenic_ecc *bch,
+                            struct ingenic_ecc_params *params,
+                            const u8 *buf, u8 *ecc_code)
+{
+       int ret;
+
+       mutex_lock(&bch->lock);
+       ret = jz4725b_bch_init(bch, params, true);
+       if (ret) {
+               dev_err(bch->dev, "Unable to init BCH with given parameters\n");
+               goto out_disable;
+       }
+
+       jz4725b_bch_write_data(bch, buf, params->size);
+
+       ret = jz4725b_bch_wait_complete(bch, BCH_BHINT_ENCF, NULL);
+       if (ret) {
+               dev_err(bch->dev, "timed out while calculating ECC\n");
+               goto out_disable;
+       }
+
+       jz4725b_bch_read_parity(bch, ecc_code, params->bytes);
+
+out_disable:
+       jz4725b_bch_disable(bch);
+       mutex_unlock(&bch->lock);
+
+       return ret;
+}
+
+static int jz4725b_correct(struct ingenic_ecc *bch,
+                          struct ingenic_ecc_params *params,
+                          u8 *buf, u8 *ecc_code)
+{
+       u32 reg, errors, bit;
+       unsigned int i;
+       int ret;
+
+       mutex_lock(&bch->lock);
+
+       ret = jz4725b_bch_init(bch, params, false);
+       if (ret) {
+               dev_err(bch->dev, "Unable to init BCH with given parameters\n");
+               goto out;
+       }
+
+       jz4725b_bch_write_data(bch, buf, params->size);
+       jz4725b_bch_write_data(bch, ecc_code, params->bytes);
+
+       ret = jz4725b_bch_wait_complete(bch, BCH_BHINT_DECF, &reg);
+       if (ret) {
+               dev_err(bch->dev, "timed out while correcting data\n");
+               goto out;
+       }
+
+       if (reg & (BCH_BHINT_ALL_F | BCH_BHINT_ALL_0)) {
+               /* Data and ECC is all 0xff or 0x00 - nothing to correct */
+               ret = 0;
+               goto out;
+       }
+
+       if (reg & BCH_BHINT_UNCOR) {
+               /* Uncorrectable ECC error */
+               ret = -EBADMSG;
+               goto out;
+       }
+
+       errors = (reg & BCH_BHINT_ERRC_MASK) >> BCH_BHINT_ERRC_SHIFT;
+
+       /* Correct any detected errors. */
+       for (i = 0; i < errors; i++) {
+               if (i & 1) {
+                       bit = (reg & BCH_BHERR_INDEX1_MASK) >> 
BCH_BHERR_INDEX1_SHIFT;
+               } else {
+                       reg = readl(bch->base + BCH_BHERR0 + (i * 4));
+                       bit = (reg & BCH_BHERR_INDEX0_MASK) >> 
BCH_BHERR_INDEX0_SHIFT;
+               }
+
+               buf[(bit >> 3)] ^= BIT(bit & 0x7);
+       }
+
+out:
+       jz4725b_bch_disable(bch);
+       mutex_unlock(&bch->lock);
+
+       return ret;
+}
+
+static const struct ingenic_ecc_ops jz4725b_bch_ops = {
+       .disable = jz4725b_bch_disable,
+       .calculate = jz4725b_calculate,
+       .correct = jz4725b_correct,
+};
+
+static const struct of_device_id jz4725b_bch_dt_match[] = {
+       { .compatible = "ingenic,jz4725b-bch", .data = &jz4725b_bch_ops },
+       {},
+};
+MODULE_DEVICE_TABLE(of, jz4725b_bch_dt_match);
+
+static struct platform_driver jz4725b_bch_driver = {
+       .probe          = ingenic_ecc_probe,
+       .driver = {
+               .name   = "jz4725b-bch",
+               .of_match_table = jz4725b_bch_dt_match,
+       },
+};
+module_platform_driver(jz4725b_bch_driver);
+
+MODULE_AUTHOR("Paul Cercueil <p...@crapouillou.net>");
+MODULE_DESCRIPTION("Ingenic JZ4725B BCH controller driver");
+MODULE_LICENSE("GPL v2");
-- 
2.11.0

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