Re: [PATCH v6 2/2] mtd: rawnand: nuvoton: add new driver for the Nuvoton MA35 SoC

From: Hui-Ping Chen
Date: Mon Oct 07 2024 - 23:20:13 EST

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In reply to: Miquel Raynal: "Re: [PATCH v6 2/2] mtd: rawnand: nuvoton: add new driver for the Nuvoton MA35 SoC"
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Dear Miquel,

Thank you for your reply.

On 2024/10/2 上午 03:57, Miquel Raynal wrote:

Hi Hui-Ping,

hpchen0nvt@xxxxxxxxx wrote on Fri, 27 Sep 2024 02:07:49 +0000:

Nuvoton MA35 SoCs NAND Flash Interface Controller
supports 2kiB, 4kiB and 8kiB page size, and up to
8-bit, 12-bit, and 24-bit hardware ECC calculation
circuit to protect data.

Signed-off-by: Hui-Ping Chen <hpchen0nvt@xxxxxxxxx>
---
drivers/mtd/nand/raw/Kconfig | 8 +
drivers/mtd/nand/raw/Makefile | 1 +
drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c | 862 +++++++++++++++++++++
3 files changed, 871 insertions(+)
create mode 100644 drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c

diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index d0aaccf72d78..e3677bcaf035 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -454,6 +454,14 @@ config MTD_NAND_TS72XX
help
Enables support for NAND controller on ts72xx SBCs.
+config MTD_NAND_NUVOTON_MA35
+ tristate "Nuvoton MA35 SoC NAND controller"
+ depends on ARCH_MA35 || COMPILE_TEST
+ depends on OF
+ help
+ Enables support for the NAND controller found on
+ the Nuvoton MA35 series SoCs.
+
comment "Misc"
config MTD_SM_COMMON
diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
index d0b0e6b83568..cc24955627f8 100644
--- a/drivers/mtd/nand/raw/Makefile
+++ b/drivers/mtd/nand/raw/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_MTD_NAND_INTEL_LGM) += intel-nand-controller.o
obj-$(CONFIG_MTD_NAND_ROCKCHIP) += rockchip-nand-controller.o
obj-$(CONFIG_MTD_NAND_PL35X) += pl35x-nand-controller.o
obj-$(CONFIG_MTD_NAND_RENESAS) += renesas-nand-controller.o
+obj-$(CONFIG_MTD_NAND_NUVOTON_MA35) += nuvoton_ma35d1_nand.o
nand-objs := nand_base.o nand_legacy.o nand_bbt.o nand_timings.o nand_ids.o
nand-objs += nand_onfi.o
diff --git a/drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c b/drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c
new file mode 100644
index 000000000000..efd60493f22a
--- /dev/null
+++ b/drivers/mtd/nand/raw/nuvoton_ma35d1_nand.c
@@ -0,0 +1,862 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/* NFI Registers */
+#define MA35_NFI_REG_DMACTL 0x400
+#define DMA_EN BIT(0)
+#define DMA_RST BIT(1)
+#define DMA_BUSY BIT(9)
+
+#define MA35_NFI_REG_DMASA 0x408
+#define MA35_NFI_REG_GCTL 0x800
+#define NAND_EN BIT(3)
+
+#define MA35_NFI_REG_NANDCTL 0x8A0
+#define SWRST BIT(0)
+#define DMA_R_EN BIT(1)
+#define DMA_W_EN BIT(2)
+#define ECC_CHK BIT(7)
+#define PROT3BEN BIT(8)
+#define PSIZE_2K BIT(16)
+#define PSIZE_4K BIT(17)
+#define PSIZE_8K GENMASK(17, 16)
+#define PSIZE_MASK GENMASK(17, 16)
+#define BCH_T24 BIT(18)
+#define BCH_T8 BIT(20)
+#define BCH_T12 BIT(21)
+#define BCH_NONE (0x0)
+#define BCH_MASK GENMASK(22, 18)
+#define ECC_EN BIT(23)
+#define DISABLE_CS0 BIT(25)
+
+#define MA35_NFI_REG_NANDINTEN 0x8A8
+#define MA35_NFI_REG_NANDINTSTS 0x8AC
+#define INT_DMA BIT(0)
+#define INT_ECC BIT(2)
+#define INT_RB0 BIT(10)
+#define INT_RB0_STS BIT(18)
+
+#define MA35_NFI_REG_NANDCMD 0x8B0
+#define MA35_NFI_REG_NANDADDR 0x8B4
+#define ENDADDR BIT(31)
+
+#define MA35_NFI_REG_NANDDATA 0x8B8
+#define MA35_NFI_REG_NANDRACTL 0x8BC
+#define MA35_NFI_REG_NANDECTL 0x8C0
+#define ENABLE_WP 0x0
+#define DISABLE_WP BIT(0)
+
+#define MA35_NFI_REG_NANDECCES0 0x8D0
+#define ECC_STATUS_MASK GENMASK(1, 0)
+#define ECC_ERR_CNT_MASK GENMASK(4, 0)
+
+#define MA35_NFI_REG_NANDECCEA0 0x900
+#define MA35_NFI_REG_NANDECCED0 0x960
+#define MA35_NFI_REG_NANDRA0 0xA00
+
+/* Define for the BCH hardware ECC engine */
+/* define the total padding bytes for 512/1024 data segment */
+#define MA35_BCH_PADDING_512 32
+#define MA35_BCH_PADDING_1024 64
+/* define the BCH parity code length for 512 bytes data pattern */
+#define MA35_PARITY_BCH8 15
+#define MA35_PARITY_BCH12 23
+/* define the BCH parity code length for 1024 bytes data pattern */
+#define MA35_PARITY_BCH24 45
+
+struct ma35_nand_info {
+ struct nand_controller controller;
+ struct nand_chip chip;
+ struct device *dev;
+ void __iomem *regs;
+ int irq;
+ struct clk *clk;
+ struct completion complete;
+ u32 bch;
+ u32 bitflips;
+ u8 *ecc_buf;
+};
+
+static int ma35_ooblayout_ecc(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+
+ if (section)
+ return -ERANGE;
+
+ oobregion->length = chip->ecc.total;
+ oobregion->offset = mtd->oobsize - oobregion->length;
+
+ return 0;
+}
+
+static int ma35_ooblayout_free(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ struct nand_chip *chip = mtd_to_nand(mtd);
+
+ if (section)
+ return -ERANGE;
+
+ oobregion->length = mtd->oobsize - chip->ecc.total - 2;
+ oobregion->offset = 2;
+
+ return 0;
+}
+
+static const struct mtd_ooblayout_ops ma35_ooblayout_ops = {
+ .free = ma35_ooblayout_free,
+ .ecc = ma35_ooblayout_ecc,
+};
+
+static inline void ma35_clear_spare(struct nand_chip *chip, int size)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ int i;
+
+ for (i = 0; i < size/4; i++)

Spacing ^

I will check and fix it.

+ writel(0xff, nand->regs + MA35_NFI_REG_NANDRA0);
+}
+
+static inline void read_remaining_bytes(struct ma35_nand_info *nand, u32 *buf,
+ u32 offset, int size)
+{
+ u32 value = readl(nand->regs + MA35_NFI_REG_NANDRA0 + offset);
+ u8 *ptr = (u8 *)buf;
+ int i;
+
+ for (i = 0; i < size; i++)
+ ptr[i] = (value >> (i * 8)) & 0xff;
+}
+
+static inline void ma35_read_spare(struct nand_chip *chip, int size, u32 *buf, u32 offset)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ int i, j;
+
+ if ((offset % 4) == 0) {
+ for (i = 0, j = 0; i < size / 4; i++, j += 4)
+ *buf++ = readl(nand->regs + MA35_NFI_REG_NANDRA0 + offset + j);
+
+ read_remaining_bytes(nand, buf, offset + j, size % 4);
+ } else {
+ read_remaining_bytes(nand, buf, offset, 4 - (offset % 4));
+ offset += 4;
+ size -= (4 - (offset % 4));
+
+ for (i = 0, j = 0; i < size / 4; i++, j += 4)
+ *buf++ = readl(nand->regs + MA35_NFI_REG_NANDRA0 + offset + j);
+
+ read_remaining_bytes(nand, buf, offset + j, size % 4);
+ }
+}
+
+static inline void ma35_write_spare(struct nand_chip *chip, int size, u32 *buf)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ u32 value;
+ int i, j;
+ u8 *ptr;
+
+ for (i = 0, j = 0; i < size / 4; i++, j += 4)
+ writel(*buf++, nand->regs + MA35_NFI_REG_NANDRA0 + j);
+
+ ptr = (u8 *)buf;
+ switch (size % 4) {
+ case 1:
+ writel(*ptr, nand->regs + MA35_NFI_REG_NANDRA0 + j);
+ break;
+ case 2:
+ value = *ptr | (*(ptr+1) << 8);
+ writel(value, nand->regs + MA35_NFI_REG_NANDRA0 + j);
+ break;
+ case 3:
+ value = *ptr | (*(ptr+1) << 8) | (*(ptr+2) << 16);
+ writel(value, nand->regs + MA35_NFI_REG_NANDRA0 + j);
+ break;
+ default:
+ break;
+ }
+}
+
+static inline void ma35_nand_target_enable(struct ma35_nand_info *nand)
+{
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) & (~DISABLE_CS0),
+ nand->regs+MA35_NFI_REG_NANDCTL);
+}
+
+static inline void ma35_nand_target_disable(struct ma35_nand_info *nand)
+{
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | DISABLE_CS0,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+}
+
+static void ma35_nand_hwecc_init(struct ma35_nand_info *nand)
+{
+ struct mtd_info *mtd = nand_to_mtd(&nand->chip);
+ u32 reg;
+
+ /* resets the internal state machine and counters

Please check the style in all you comments.

/*
* Reset the

I will check and fix all.

+ * This bit will be auto cleared after a few clock cycles.
+ */
+ reg = readl(nand->regs + MA35_NFI_REG_NANDCTL);
+ reg |= SWRST;
+ writel(reg, nand->regs + MA35_NFI_REG_NANDCTL);

This has a way wider impact than just configuring the hw ECC engine,
no? Are you sure you want to do this now? I believe it should be in its
own helper, and you want to do it earlier than that, like before the
discovery step (and also in the resume path).

I carefully examined our NAND controller and found that this action is unnecessary.

I will remove it.

+ while (readl(nand->regs + MA35_NFI_REG_NANDCTL) & SWRST)
+ ;

cpu_relax()

I will remove this while-loop, so this API will not be added.

+
+ /* Redundant area size */
+ writel(mtd->oobsize, nand->regs + MA35_NFI_REG_NANDRACTL);
+
+ /* Protect redundant 3 bytes */
+ reg = readl(nand->regs + MA35_NFI_REG_NANDCTL);
+ reg |= (PROT3BEN | ECC_CHK);
+ writel(reg, nand->regs + MA35_NFI_REG_NANDCTL);
+
+ if (nand->bch == BCH_NONE) {

Please use the definitions/constants from the core.

Will use ecc.strength instead.

+ /* Disable H/W ECC, ECC parity check enable bit during read page */
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) & (~ECC_EN),
+ nand->regs + MA35_NFI_REG_NANDCTL);

Move the readl before the if and save it in the reg variable.

In general please do not overload the lines like that when it's not
needed.

It will be changed to:

reg = readl();

writel(...);

+ } else {
+ /* Set BCH algorithm */
+ writel((readl(nand->regs + MA35_NFI_REG_NANDCTL) & (~BCH_MASK)) |

Parenthesis are not needed ^

I will remove the parentheses.

+ nand->bch, nand->regs + MA35_NFI_REG_NANDCTL);
+
+ /* Enable H/W ECC, ECC parity check enable bit during read page */
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | ECC_EN,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ }
+}
+
+/* Correct data by BCH alrogithm */
+static void ma35_nfi_correct(struct ma35_nand_info *nand, u8 index,
+ u8 err_cnt, u8 *addr)
+{
+ u32 temp_data[24], temp_addr[24];
+ u32 padding_len, parity_len;
+ u32 value, offset, remain;
+ u32 err_data[6];
+ u8 i, j;
+
+ /* configurations */
+ switch (nand->bch) {
+ case BCH_T24:
+ parity_len = MA35_PARITY_BCH24;
+ padding_len = MA35_BCH_PADDING_1024;
+ break;
+ case BCH_T12:
+ parity_len = MA35_PARITY_BCH12;
+ padding_len = MA35_BCH_PADDING_512;
+ break;
+ case BCH_T8:
+ parity_len = MA35_PARITY_BCH8;
+ padding_len = MA35_BCH_PADDING_512;
+ break;
+ default:
+ dev_warn(nand->dev, "NAND ERROR: invalid SMCR_BCH_TSEL = 0x%08X\n",
+ (u32)(readl(nand->regs + MA35_NFI_REG_NANDCTL) & BCH_MASK));
+ return;
+ }
+
+ /* got valid BCH_ECC_DATAx and parse them to temp_data[]
+ * got the valid register number of BCH_ECC_DATAx since
+ * one register include 4 error bytes
+ */
+ j = (err_cnt + 3) / 4;
+ j = (j > 6) ? 6 : j;
+ for (i = 0; i < j; i++)
+ err_data[i] = readl(nand->regs + MA35_NFI_REG_NANDECCED0 + i * 4);
+
+ for (i = 0; i < j; i++) {
+ temp_data[i*4+0] = err_data[i] & 0xff;
+ temp_data[i*4+1] = (err_data[i] >> 8) & 0xff;
+ temp_data[i*4+2] = (err_data[i] >> 16) & 0xff;
+ temp_data[i*4+3] = (err_data[i] >> 24) & 0xff;
+ }
+
+ /* got valid REG_BCH_ECC_ADDRx and parse them to temp_addr[]
+ * got the valid register number of REG_BCH_ECC_ADDRx since
+ * one register include 2 error addresses
+ */
+ j = (err_cnt + 1) / 2;
+ j = (j > 12) ? 12 : j;
+ for (i = 0; i < j; i++) {
+ temp_addr[i*2+0] = readl(nand->regs + MA35_NFI_REG_NANDECCEA0 + i * 4)
+ & 0x07ff;
+ temp_addr[i*2+1] = (readl(nand->regs + MA35_NFI_REG_NANDECCEA0 + i * 4)
+ >> 16) & 0x07ff;
+ }
+
+ /* pointer to begin address of field that with data error */
+ addr += index * nand->chip.ecc.steps;
+
+ /* correct each error bytes */
+ for (i = 0; i < err_cnt; i++) {
+ u32 corrected_index = temp_addr[i];
+
+ /* for wrong data in field */
+ if (corrected_index < nand->chip.ecc.steps)
+ *(addr + corrected_index) ^= temp_data[i];
+
+ /* for wrong first-3-bytes in redundancy area */
+ else if (corrected_index < (nand->chip.ecc.steps + 3)) {
+ corrected_index -= nand->chip.ecc.steps;
+ temp_addr[i] += (parity_len * index); /* field offset */
+
+ value = readl(nand->regs + MA35_NFI_REG_NANDRA0);
+ value ^= temp_data[i] << (8 * corrected_index);
+ writel(value, nand->regs + MA35_NFI_REG_NANDRA0);
+ }
+ /* for wrong parity code in redundancy area
+ * BCH_ERR_ADDRx = [data in field] + [3 bytes] + [xx] + [parity code]
+ * |<-- padding bytes -->|
+ * The BCH_ERR_ADDRx for last parity code always = field size + padding size.
+ * So, the first parity code = field size + padding size - parity code length.
+ * For example, for BCH T12, the first parity code = 512 + 32 - 23 = 521.
+ * That is, error byte address offset within field is
+ */
+ else {
+ corrected_index -= (nand->chip.ecc.steps + padding_len - parity_len);
+
+ /* final address = first parity code of first field +
+ * offset of fields +
+ * offset within field
+ */
+ offset = (readl(nand->regs + MA35_NFI_REG_NANDRACTL) & 0x1ff) -
+ (parity_len * nand->chip.ecc.steps) +
+ (parity_len * index) + corrected_index;
+
+ remain = offset % 4;
+ value = readl(nand->regs + MA35_NFI_REG_NANDRA0 + offset - remain);
+ value ^= temp_data[i] << (8 * remain);
+ writel(value, nand->regs + MA35_NFI_REG_NANDRA0 + offset - remain);
+ }
+ }
+}
+
+static int ma35_nfi_ecc_check(struct nand_chip *chip, u8 *addr)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ int i, j, nchunks = 0;
+ int report_err = 0;
+ int err_cnt = 0;
+ u32 status;
+
+ nchunks = mtd->writesize / chip->ecc.steps;
+ if (nchunks < 4)
+ nchunks = 1;
+ else
+ nchunks /= 4;
+
+ for (j = 0; j < nchunks; j++) {
+ status = readl(nand->regs + MA35_NFI_REG_NANDECCES0 + j * 4);
+ if (!status)
+ continue;
+
+ for (i = 0; i < 4; i++) {
+ if (!(status & ECC_STATUS_MASK)) {
+ /* No error */
+ status >>= 8;
+ continue;

Remove this block, it will do the same and be more clear.

Indeed, this is unnecessary. I will remove it.

+ } else if ((status & ECC_STATUS_MASK) == 0x01) {
+ /* Correctable error */
+ err_cnt = (status >> 2) & ECC_ERR_CNT_MASK;
+ ma35_nfi_correct(nand, j*4+i, err_cnt, addr);

Spacing ^^^^^^

I will check and fix it.

+ report_err += err_cnt;
+ } else {
+ /* uncorrectable error */
+ dev_warn(nand->dev, "uncorrectable error! 0x%4x\n", status);
+ return -1;

Not a valid error code

I will change it to return -EBADMSG;

+ }
+ status >>= 8;
+ }
+ }
+ return report_err;
+}
+
+static void ma35_nand_dmac_init(struct ma35_nand_info *nand)
+{
+ /* DMAC reset and enable */
+ writel(DMA_RST | DMA_EN, nand->regs + MA35_NFI_REG_DMACTL);
+ writel(DMA_EN, nand->regs + MA35_NFI_REG_DMACTL);
+
+ /* Clear DMA finished flag */
+ writel(INT_DMA | INT_ECC, nand->regs + MA35_NFI_REG_NANDINTSTS);
+
+ init_completion(&nand->complete);

You're gonna call init_completion more than once during suspend/resume
cycles, this is unsafe.

I will move init_completion to probe, and then add reinit_completion in the read/write page.

+}
+
+static int ma35_nand_do_write(struct nand_chip *chip, const u8 *addr, u32 len)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ dma_addr_t dma_addr;
+ int ret = 0, i;
+ u32 reg;
+
+ if (len != mtd->writesize) {
+ for (i = 0; i < len; i++)
+ writel(addr[i], nand->regs + MA35_NFI_REG_NANDDATA);
+ return 0;
+ }
+
+ ma35_nand_dmac_init(nand);
+
+ writel(mtd->oobsize, nand->regs + MA35_NFI_REG_NANDRACTL);
+
+ writel(INT_DMA, nand->regs + MA35_NFI_REG_NANDINTEN);
+ /* To mark this page as dirty. */
+ reg = readl(nand->regs + MA35_NFI_REG_NANDRA0);
+ if (reg & 0xffff0000)
+ writel(reg & 0xffff, nand->regs + MA35_NFI_REG_NANDRA0);
+
+ dma_addr = dma_map_single(nand->dev, (void *)addr, len, DMA_TO_DEVICE);
+ ret = dma_mapping_error(nand->dev, dma_addr);
+ if (ret) {
+ dev_err(nand->dev, "dma mapping error\n");
+ return -EINVAL;
+ }
+ dma_sync_single_for_device(nand->dev, dma_addr, len, DMA_TO_DEVICE);
+
+ writel((unsigned long)dma_addr, nand->regs + MA35_NFI_REG_DMASA);
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | DMA_W_EN,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ ret = wait_for_completion_timeout(&nand->complete, msecs_to_jiffies(1000));
+ if (!ret) {
+ dev_err(nand->dev, "write timeout\n");
+ ret = -ETIMEDOUT;
+ }
+
+ dma_unmap_single(nand->dev, dma_addr, len, DMA_TO_DEVICE);
+
+ return ret;
+}
+
+static int ma35_nand_do_read(struct nand_chip *chip, u8 *addr, u32 len)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ int ret = 0, cnt = 0, i;
+ dma_addr_t dma_addr;
+ u32 reg;
+
+ if (len != mtd->writesize) {
+ for (i = 0; i < len; i++)
+ *(addr+i) = (u8)readl(nand->regs + MA35_NFI_REG_NANDDATA);

Mmh, that line is strange. Please don't do that.

addr[i] = readb() ?

It will be fixed to readb().

+ return 0;
+ }
+
+ ma35_nand_dmac_init(nand);
+
+ writel(mtd->oobsize, nand->regs + MA35_NFI_REG_NANDRACTL);
+
+ /* setup and start DMA using dma_addr */
+ dma_addr = dma_map_single(nand->dev, (void *)addr, len, DMA_FROM_DEVICE);
+ ret = dma_mapping_error(nand->dev, dma_addr);
+ if (ret) {
+ dev_err(nand->dev, "dma mapping error\n");
+ return -EINVAL;
+ }
+
+ writel((unsigned long)dma_addr, nand->regs + MA35_NFI_REG_DMASA);

Please enforce a dma mask of 32 (even though it might be the fault).

I will change it to dma_addr & 0xffffffff.

+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | DMA_R_EN,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ ret = wait_for_completion_timeout(&nand->complete, msecs_to_jiffies(1000));
+ if (!ret) {
+ dev_err(nand->dev, "read timeout\n");
+ ret = -ETIMEDOUT;
+ }
+
+ dma_unmap_single(nand->dev, dma_addr, len, DMA_FROM_DEVICE);
+
+ reg = readl(nand->regs + MA35_NFI_REG_NANDINTSTS);
+ if (reg & INT_ECC) {
+ cnt = ma35_nfi_ecc_check(&nand->chip, addr);
+ if (cnt < 0) {
+ mtd->ecc_stats.failed++;
+ writel(DMA_RST | DMA_EN, nand->regs + MA35_NFI_REG_DMACTL);
+ writel(readl(nand->regs + MA35_NFI_REG_NANDCTL) | SWRST,
+ nand->regs + MA35_NFI_REG_NANDCTL);
+ } else {
+ mtd->ecc_stats.corrected += cnt;
+ nand->bitflips = cnt;
+ }
+ writel(INT_ECC, nand->regs + MA35_NFI_REG_NANDINTSTS);
+ }
+
+ return ret;
+}
+
+static int ma35_nand_write_page_hwecc(struct nand_chip *chip, const u8 *buf,
+ int oob_required, int page)
+{
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ void *ecc_calc = chip->ecc.calc_buf;
+
+ ma35_clear_spare(chip, mtd->oobsize);
+ ma35_write_spare(chip, mtd->oobsize - chip->ecc.total,
+ (u32 *)chip->oob_poi);
+
+ nand_prog_page_begin_op(chip, page, 0, buf, mtd->writesize);
+ nand_prog_page_end_op(chip);
+
+ /* Copy parity code in NANDRA to calc */
+ ma35_read_spare(chip, chip->ecc.total, (u32 *)ecc_calc,
+ mtd->oobsize - chip->ecc.total);
+
+ /* Copy parity code in calc to oob_poi */
+ memcpy(chip->oob_poi + (mtd->oobsize - chip->ecc.total),
+ ecc_calc, chip->ecc.total);
+
+ return 0;
+}
+
+static int ma35_nand_read_page_hwecc(struct nand_chip *chip, u8 *buf,
+ int oob_required, int page)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ u32 reg;
+
+ /* read the OOB area */
+ nand_read_oob_op(chip, page, 0, chip->oob_poi, mtd->oobsize);
+ nand->bitflips = 0;

Why storing this value in your structure?

Because ecc.read_page needs to return bit flips, it is necessary to log them.

+
+ /* copy OOB data to NANDRA for page read */
+ ma35_write_spare(chip, mtd->oobsize, (u32 *)chip->oob_poi);
+
+ reg = readl(nand->regs + MA35_NFI_REG_NANDRA0);
+ if (reg & 0xffff0000) {
+ memset((void *)buf, 0xff, mtd->writesize);
+ } else {
+ /* read data from nand */
+ nand_read_page_op(chip, page, 0, buf, mtd->writesize);

ret =
if (ret)
...

I will add a return value here.

+
+ /* restore OOB data from SMRA */
+ ma35_read_spare(chip, mtd->oobsize, (u32 *)chip->oob_poi, 0);

same

ma35_read_spare() is declared as void, with no return value.

SMRA will be changed to NANDRA registers.

+ }
+
+ return nand->bitflips;
+}
+
+static int ma35_nand_read_oob_hwecc(struct nand_chip *chip, int page)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ u32 reg;
+
+ nand_read_oob_op(chip, page, 0, chip->oob_poi, mtd->oobsize);
+
+ /* copy OOB data to NANDRA for page read */

What is NANDRA? does not mean anything to me.

NANDRA is the Redundant Area Word of the MA35 NAND controller.

The controller reads ECC parity from this area for calculations or uses the information for check.

I will change NANDRA to NANDRA registers.

+ ma35_write_spare(chip, mtd->oobsize, (u32 *)chip->oob_poi);
+
+ reg = readl(nand->regs + MA35_NFI_REG_NANDRA0);
+ if (reg & 0xffff0000)
+ memset((void *)chip->oob_poi, 0xff, mtd->oobsize);

What does this mean?

MA35 NAND controller checks oob bytes 2 and 3.

If this page has been written, oob bytes 2 and 3 will be set to 0.

Therefore, if bytes 2 and 3 are not 0, it indicates an empty page, and it will return 0xff.

+
+ return 0;
+}
+
+static irqreturn_t ma35_nand_irq(int irq, void *id)
+{
+ struct ma35_nand_info *nand = (struct ma35_nand_info *)id;
+ u32 isr;
+
+ isr = readl(nand->regs + MA35_NFI_REG_NANDINTSTS);
+ if (isr & INT_DMA) {
+ writel(INT_DMA, nand->regs + MA35_NFI_REG_NANDINTSTS);
+ complete(&nand->complete);
+ }

I guess a more future proof implementation would always writel(isr); to
silence the interrupt. Otherwise of course you must call complete()
only upon isr & INT_DMA.

This part can remove the if(), but writel(isr) is not feasible.

The isr may contain the ECC flag, and clearing it could cause a miss in ECC handling.

I will change it to:

writel(INT_DMA, nand->regs + MA35_NFI_REG_NANDINTSTS);
complete(&nand->complete);

+
+ return IRQ_HANDLED;
+}
+
+static int ma35_nand_attach_chip(struct nand_chip *chip)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ struct mtd_info *mtd = nand_to_mtd(chip);
+ unsigned int reg;
+
+ if (chip->options & NAND_BUSWIDTH_16) {
+ dev_err(nand->dev, "16 bits bus width not supported");
+ return -EINVAL;
+ }
+
+ /* support only ecc hw mode */

Why ? Please don't.

I will add handling for other cases.

+ if (chip->ecc.engine_type != NAND_ECC_ENGINE_TYPE_ON_HOST) {
+ dev_err(nand->dev, "ecc.engine_type not supported\n");
+ return -EINVAL;
+ }
+
+ nand->ecc_buf = devm_kzalloc(nand->dev, mtd->writesize + mtd->oobsize,
+ GFP_KERNEL);
+ if (!nand->ecc_buf)
+ return -ENOMEM;
+ chip->ecc.calc_buf = nand->ecc_buf;

Are you sure you need this? I don't see the point.

This is unnecessary; I will remove it.

+
+ /* Set PSize */
+ reg = readl(nand->regs + MA35_NFI_REG_NANDCTL) & (~PSIZE_MASK);
+ if (mtd->writesize == 2048)
+ writel(reg | PSIZE_2K, nand->regs + MA35_NFI_REG_NANDCTL);
+ else if (mtd->writesize == 4096)
+ writel(reg | PSIZE_4K, nand->regs + MA35_NFI_REG_NANDCTL);
+ else if (mtd->writesize == 8192)
+ writel(reg | PSIZE_8K, nand->regs + MA35_NFI_REG_NANDCTL);
+
+ chip->ecc.steps = mtd->writesize / chip->ecc.size;
+ if (chip->ecc.strength == 0) {
+ nand->bch = BCH_NONE; /* No ECC */
+ chip->ecc.total = 0;
+ } else if (chip->ecc.strength <= 8) {
+ nand->bch = BCH_T8; /* T8 */

bch is probably a bad name, and in general I don't see the point of
saving this value. Just check the ECC strength in the above switch
cases and don't use this intermediate variable.

I will change it to directly use ecc.strength for the check.

+ chip->ecc.total = chip->ecc.steps * MA35_PARITY_BCH8;
+ } else if (chip->ecc.strength <= 12) {
+ nand->bch = BCH_T12; /* T12 */
+ chip->ecc.total = chip->ecc.steps * MA35_PARITY_BCH12;
+ } else if (chip->ecc.strength <= 24) {
+ nand->bch = BCH_T24; /* T24 */
+ chip->ecc.total = chip->ecc.steps * MA35_PARITY_BCH24;
+ } else {
+ dev_warn(nand->dev, "NAND Controller is not support this flash. (%d, %d)\n",
+ mtd->writesize, mtd->oobsize);

This must be a dev_err() and return an error immediately.

Also the string is not correct.

I will change it to:

dev_err(nand->dev, "ECC strength error\n");
return -EINVAL;

+ }
+
+ chip->ecc.bytes = chip->ecc.total / chip->ecc.steps;
+ mtd_set_ooblayout(mtd, &ma35_ooblayout_ops);
+
+ /* add mtd-id. The string should same as uboot definition */
+ mtd->name = "nand0";

No! There are DT labels for that and mtd->name will automatically be
set when calling nand_set_flash_node().

I will remove it.

+
+ ma35_nand_hwecc_init(nand);
+
+ writel(DISABLE_WP, nand->regs + MA35_NFI_REG_NANDECTL);
+
+ return 0;
+}
+
+static int ma35_nfc_exec_instr(struct nand_chip *chip,
+ const struct nand_op_instr *instr)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ unsigned int i;
+ u32 status;
+
+ switch (instr->type) {
+ case NAND_OP_CMD_INSTR:
+ writel(instr->ctx.cmd.opcode, nand->regs + MA35_NFI_REG_NANDCMD);
+ return 0;
+ case NAND_OP_ADDR_INSTR:
+ for (i = 0; i < instr->ctx.addr.naddrs; i++) {
+ if (i == (instr->ctx.addr.naddrs - 1))
+ writel(instr->ctx.addr.addrs[i] | ENDADDR,
+ nand->regs + MA35_NFI_REG_NANDADDR);
+ else
+ writel(instr->ctx.addr.addrs[i],
+ nand->regs + MA35_NFI_REG_NANDADDR);
+ }
+ return 0;
+ case NAND_OP_DATA_IN_INSTR:
+ ma35_nand_do_read(chip, instr->ctx.data.buf.in, instr->ctx.data.len);
+ return 0;
+ case NAND_OP_DATA_OUT_INSTR:
+ ma35_nand_do_write(chip, instr->ctx.data.buf.out, instr->ctx.data.len);
+ return 0;
+ case NAND_OP_WAITRDY_INSTR:
+ return readl_poll_timeout(nand->regs + MA35_NFI_REG_NANDINTSTS, status,
+ status & INT_RB0, 20,
+ instr->ctx.waitrdy.timeout_ms * 1000);

MSEC_PER_SEC

I will change it to instr->ctx.waitrdy.timeout_ms * MSEC_PER_SEC.

+ default:
+ break;
+ }
+
+ return -EINVAL;
+}

This is much better than the legacy hooks!

Thanks.

+
+static int ma35_nfc_exec_op(struct nand_chip *chip,
+ const struct nand_operation *op,
+ bool check_only)
+{
+ struct ma35_nand_info *nand = nand_get_controller_data(chip);
+ int ret = 0;
+ u32 i, reg;
+
+ if (check_only)
+ return 0;
+
+ ma35_nand_target_enable(nand);
+
+ reg = readl(nand->regs + MA35_NFI_REG_NANDINTSTS);
+ reg |= INT_RB0;

This RB pin looks like something hardcoded, whereas it should not :-)

If you have several RB, it means you have several CS as well!

The MA35 NAND controller is indeed expected to support two sets of CS and RB.

However, currently, the MA35 series only supports one set, so this name will be changed to RB.

+ writel(reg, nand->regs + MA35_NFI_REG_NANDINTSTS);
+
+ for (i = 0; i < op->ninstrs; i++) {
+ ret = ma35_nfc_exec_instr(chip, &op->instrs[i]);
+ if (ret)
+ break;
+ }
+
+ ma35_nand_target_disable(nand);
+
+ return ret;
+}
+
+static const struct nand_controller_ops ma35_nfc_ops = {
+ .attach_chip = ma35_nand_attach_chip,
+ .exec_op = ma35_nfc_exec_op,
+};
+
+static int ma35_nand_probe(struct platform_device *pdev)
+{
+ struct ma35_nand_info *nand;
+ struct nand_chip *chip;
+ struct mtd_info *mtd;
+ int ret = 0;
+
+ nand = devm_kzalloc(&pdev->dev, sizeof(*nand), GFP_KERNEL);
+ if (!nand)
+ return -ENOMEM;
+
+ nand_controller_init(&nand->controller);
+ nand->controller.ops = &ma35_nfc_ops;
+
+ nand->regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(nand->regs))
+ return PTR_ERR(nand->regs);
+
+ nand->dev = &pdev->dev;
+ chip = &nand->chip;
+ nand_set_controller_data(chip, nand);
+ nand_set_flash_node(chip, pdev->dev.of_node);
+
+ nand->clk = devm_clk_get_enabled(&pdev->dev, "nand_gate");
+ if (IS_ERR(nand->clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(nand->clk),
+ "failed to find nand clock\n");

NAND

I will fix it.

+
+ nand->irq = platform_get_irq(pdev, 0);
+ if (nand->irq < 0)
+ return dev_err_probe(&pdev->dev, nand->irq,
+ "failed to get platform irq\n");
+
+ ret = devm_request_irq(&pdev->dev, nand->irq, ma35_nand_irq,
+ IRQF_TRIGGER_HIGH, "ma35d1-nand", nand);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request NAND irq\n");
+ return -ENXIO;
+ }
+
+ nand->chip.controller = &nand->controller;
+ platform_set_drvdata(pdev, nand);
+
+ chip->options |= NAND_NO_SUBPAGE_WRITE | NAND_USES_DMA;
+
+ chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_ON_HOST;
+ chip->ecc.write_page = ma35_nand_write_page_hwecc;
+ chip->ecc.read_page = ma35_nand_read_page_hwecc;
+ chip->ecc.read_oob = ma35_nand_read_oob_hwecc;

You support to disable the ECC engine, so you must support software
corrections as well. Please don't force hw ECC use. Please look at
other implementations, there is usually a helper with a switch case
which supports various ECC configurations.

I will refer to other implementations and will add handling for other cases.

+
+ mtd = nand_to_mtd(chip);
+ mtd->priv = chip;
+ mtd->owner = THIS_MODULE;
+ mtd->dev.parent = &pdev->dev;
+
+ writel(NAND_EN, nand->regs + MA35_NFI_REG_GCTL);

I would expect your reset bit to be set before this writel.

Are you referring to SWRST? I will call the reset engine before enabling it.

+
+ ret = nand_scan(chip, 1);
+ if (ret)
+ return ret;
+
+ ret = mtd_device_register(mtd, NULL, 0);
+ if (ret) {
+ nand_cleanup(chip);
+ return ret;
+ }
+
+ return ret;

return 0; then

I will change it to return 0;

+}
+
+static void ma35_nand_remove(struct platform_device *pdev)
+{
+ struct ma35_nand_info *nand = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = mtd_device_unregister(nand_to_mtd(&nand->chip));
+ WARN_ON(ret);
+ nand_cleanup(&nand->chip);
+}
+
+/* PM Support */
+#ifdef CONFIG_PM
+static int ma35_nand_suspend(struct platform_device *pdev, pm_message_t pm)
+{
+ struct ma35_nand_info *nand = platform_get_drvdata(pdev);
+ int ret = 0;
+ u32 val;
+
+ /* wait DMAC to ready */

be

I will fix it.

+ ret = readl_poll_timeout(nand->regs + MA35_NFI_REG_DMACTL, val,
+ !(val & DMA_BUSY), 50, HZ/2);
+ if (ret)
+ dev_warn(&pdev->dev, "dma busy\n");

DMA

And please make a sentence.

I will fix it.

+
+ clk_disable(nand->clk);

If you decide to return ret != 0, shall you really disable this clock ?

I will change it to:

    /* wait DMAC to be ready */
    ret = readl_poll_timeout(nand->regs + MA35_NFI_REG_DMACTL, val,
                 !(val & DMA_BUSY), 50, HZ/2);
    if (ret) {
        dev_warn(&pdev->dev, "wait DMA done timeout.\n");
        return ret;
    }

    clk_disable(nand->clk);

    return 0;

+
+ return ret;
+}
+
+static int ma35_nand_resume(struct platform_device *pdev)
+{
+ struct ma35_nand_info *nand = platform_get_drvdata(pdev);
+
+ clk_enable(nand->clk);
+ ma35_nand_hwecc_init(nand);

The naming is wrong. This init is not just the hw ECC controller.

This will be changed to handle the initialization of the NAND controller and ECC controller.

It will also call nand_reset().

+ ma35_nand_dmac_init(nand);
+
+ return 0;
+}
+
+#else
+#define ma35_nand_suspend NULL
+#define ma35_nand_resume NULL
+#endif
+
+static const struct of_device_id ma35_nfi_of_match[] = {

ma35_nfi or ma35_nand, take one and please stick to it.

Will be unified into ma35_nand.

+ { .compatible = "nuvoton,ma35d1-nand" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ma35_nfi_of_match);
+
+static struct platform_driver ma35_nand_driver = {
+ .driver = {
+ .name = "ma35d1-nand",
+ .of_match_table = ma35_nfi_of_match,
+ },
+ .probe = ma35_nand_probe,
+ .remove = ma35_nand_remove,
+ .suspend = ma35_nand_suspend,
+ .resume = ma35_nand_resume,
+};
+
+module_platform_driver(ma35_nand_driver);
+
+MODULE_DESCRIPTION("Nuvoton ma35 NAND driver");
+MODULE_AUTHOR("Hui-Ping Chen <hpchen0nvt@xxxxxxxxx>");
+MODULE_LICENSE("GPL");

Thanks,
Miquèl

Best regards,

Hui-Ping Chen

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