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

Miquel Raynal
2024-10-01T19:58:06Z

Hi Hui-Ping,

hpchen0nvt@gmail.com 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@gmail.com>
> ---
> 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 ^

> + 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

> + * 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).

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

cpu_relax()

> +
> + /* 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.

> + /* 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.

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

Parenthesis are not needed ^

> + 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.

> + } 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 ^^^^^^

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

Not a valid error code

> + }
> + 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.

> +}
> +
> +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() ?

> + 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).

> + 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?

> +
> + /* 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)
...

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

same

> + }
> +
> + 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.

> + 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?

> +
> + 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.

> +
> + 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.

> + 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.

> +
> + /* 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.

> + 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.

> + }
> +
> + 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().

> +
> + 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

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

This is much better than the legacy hooks!

> +
> +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!

> + 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

> +
> + 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.

> +
> + 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.

> +
> + 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

> +}
> +
> +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

> + 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.

> +
> + clk_disable(nand->clk);

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

> +
> + 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.

> + 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.

> + { .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@gmail.com>");
> +MODULE_LICENSE("GPL");

Thanks,
Miquèl