Re: [PATCH v3 5/9] mtd: nand: add sunxi NAND flash controller support

Ezequiel Garcia
2014-05-09T16:03:41Z

Hello Boris,

Sorry for the review delay.

Emilio, if you have hardware to test this, it would be nice to give
Boris some Tested-by?

On 12 Mar 07:07 PM, Boris BREZILLON wrote:
> Add support for the sunxi NAND Flash Controller (NFC).
>
> Signed-off-by: Boris BREZILLON <b.brezillon.dev@gmail.com>
> ---
> drivers/mtd/nand/Kconfig | 6 +
> drivers/mtd/nand/Makefile | 1 +
> drivers/mtd/nand/sunxi_nand.c | 1276 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 1283 insertions(+)
> create mode 100644 drivers/mtd/nand/sunxi_nand.c
>
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index 90ff447..8a28c06 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -510,4 +510,10 @@ config MTD_NAND_XWAY
> Enables support for NAND Flash chips on Lantiq XWAY SoCs. NAND is attached
> to the External Bus Unit (EBU).
>
> +config MTD_NAND_SUNXI
> + tristate "Support for NAND on Allwinner SoCs"
> + depends on ARCH_SUNXI
> + help
> + Enables support for NAND Flash chips on Allwinner SoCs.
> +
> endif # MTD_NAND
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index 0b8a822..34f45d8 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -49,5 +49,6 @@ obj-$(CONFIG_MTD_NAND_JZ4740) += jz4740_nand.o
> obj-$(CONFIG_MTD_NAND_GPMI_NAND) += gpmi-nand/
> obj-$(CONFIG_MTD_NAND_XWAY) += xway_nand.o
> obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH) += bcm47xxnflash/
> +obj-$(CONFIG_MTD_NAND_SUNXI) += sunxi_nand.o
>
> nand-objs := nand_base.o nand_bbt.o
> diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
> new file mode 100644
> index 0000000..e93cc44
> --- /dev/null
> +++ b/drivers/mtd/nand/sunxi_nand.c
> @@ -0,0 +1,1276 @@
> +/*
> + * Copyright (C) 2013 Boris BREZILLON <b.brezillon.dev@gmail.com>
> + *
> + * Derived from:
> + * https://github.com/yuq/sunxi-nfc-mtd
> + * Copyright (C) 2013 Qiang Yu <yuq825@gmail.com>
> + *
> + * https://github.com/hno/Allwinner-Info
> + * Copyright (C) 2013 Henrik Nordström <Henrik Nordström>
> + *
> + * Copyright (C) 2013 Dmitriy B. <rzk333@gmail.com>
> + * Copyright (C) 2013 Sergey Lapin <slapin@ossfans.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/dma-mapping.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/platform_device.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_mtd.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/nand.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/dmaengine.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +
> +#define NFC_REG_CTL 0x0000
> +#define NFC_REG_ST 0x0004
> +#define NFC_REG_INT 0x0008
> +#define NFC_REG_TIMING_CTL 0x000C
> +#define NFC_REG_TIMING_CFG 0x0010
> +#define NFC_REG_ADDR_LOW 0x0014
> +#define NFC_REG_ADDR_HIGH 0x0018
> +#define NFC_REG_SECTOR_NUM 0x001C
> +#define NFC_REG_CNT 0x0020
> +#define NFC_REG_CMD 0x0024
> +#define NFC_REG_RCMD_SET 0x0028
> +#define NFC_REG_WCMD_SET 0x002C
> +#define NFC_REG_IO_DATA 0x0030
> +#define NFC_REG_ECC_CTL 0x0034
> +#define NFC_REG_ECC_ST 0x0038
> +#define NFC_REG_DEBUG 0x003C
> +#define NFC_REG_ECC_CNT0 0x0040
> +#define NFC_REG_ECC_CNT1 0x0044
> +#define NFC_REG_ECC_CNT2 0x0048
> +#define NFC_REG_ECC_CNT3 0x004c
> +#define NFC_REG_USER_DATA_BASE 0x0050
> +#define NFC_REG_SPARE_AREA 0x00A0
> +#define NFC_RAM0_BASE 0x0400
> +#define NFC_RAM1_BASE 0x0800
> +
> +/*define bit use in NFC_CTL*/

nit: Use BIT() for these?

> +#define NFC_EN (1 << 0)
> +#define NFC_RESET (1 << 1)
> +#define NFC_BUS_WIDYH (1 << 2)
> +#define NFC_RB_SEL (1 << 3)
> +#define NFC_CE_SEL (7 << 24)
> +#define NFC_CE_CTL (1 << 6)
> +#define NFC_CE_CTL1 (1 << 7)
> +#define NFC_PAGE_SIZE (0xf << 8)
> +#define NFC_SAM (1 << 12)
> +#define NFC_RAM_METHOD (1 << 14)
> +#define NFC_DEBUG_CTL (1 << 31)
> +
> +/*define bit use in NFC_ST*/
> +#define NFC_RB_B2R (1 << 0)
> +#define NFC_CMD_INT_FLAG (1 << 1)
> +#define NFC_DMA_INT_FLAG (1 << 2)
> +#define NFC_CMD_FIFO_STATUS (1 << 3)
> +#define NFC_STA (1 << 4)
> +#define NFC_NATCH_INT_FLAG (1 << 5)
> +#define NFC_RB_STATE0 (1 << 8)
> +#define NFC_RB_STATE1 (1 << 9)
> +#define NFC_RB_STATE2 (1 << 10)
> +#define NFC_RB_STATE3 (1 << 11)
> +
> +/*define bit use in NFC_INT*/
> +#define NFC_B2R_INT_ENABLE (1 << 0)
> +#define NFC_CMD_INT_ENABLE (1 << 1)
> +#define NFC_DMA_INT_ENABLE (1 << 2)
> +#define NFC_INT_MASK (NFC_B2R_INT_ENABLE | \
> + NFC_CMD_INT_ENABLE | \
> + NFC_DMA_INT_ENABLE)
> +
> +
> +/*define bit use in NFC_CMD*/
> +#define NFC_CMD_LOW_BYTE (0xff << 0)
> +#define NFC_CMD_HIGH_BYTE (0xff << 8)
> +#define NFC_ADR_NUM (0x7 << 16)
> +#define NFC_SEND_ADR (1 << 19)
> +#define NFC_ACCESS_DIR (1 << 20)
> +#define NFC_DATA_TRANS (1 << 21)
> +#define NFC_SEND_CMD1 (1 << 22)
> +#define NFC_WAIT_FLAG (1 << 23)
> +#define NFC_SEND_CMD2 (1 << 24)
> +#define NFC_SEQ (1 << 25)
> +#define NFC_DATA_SWAP_METHOD (1 << 26)
> +#define NFC_ROW_AUTO_INC (1 << 27)
> +#define NFC_SEND_CMD3 (1 << 28)
> +#define NFC_SEND_CMD4 (1 << 29)
> +#define NFC_CMD_TYPE (3 << 30)
> +
> +/* define bit use in NFC_RCMD_SET*/
> +#define NFC_READ_CMD (0xff << 0)
> +#define NFC_RANDOM_READ_CMD0 (0xff << 8)
> +#define NFC_RANDOM_READ_CMD1 (0xff << 16)
> +
> +/*define bit use in NFC_WCMD_SET*/
> +#define NFC_PROGRAM_CMD (0xff << 0)
> +#define NFC_RANDOM_WRITE_CMD (0xff << 8)
> +#define NFC_READ_CMD0 (0xff << 16)
> +#define NFC_READ_CMD1 (0xff << 24)
> +
> +/*define bit use in NFC_ECC_CTL*/
> +#define NFC_ECC_EN (1 << 0)
> +#define NFC_ECC_PIPELINE (1 << 3)
> +#define NFC_ECC_EXCEPTION (1 << 4)
> +#define NFC_ECC_BLOCK_SIZE (1 << 5)
> +#define NFC_RANDOM_EN (1 << 9)
> +#define NFC_RANDOM_DIRECTION (1 << 10)
> +#define NFC_ECC_MODE_SHIFT 12
> +#define NFC_ECC_MODE (0xf << NFC_ECC_MODE_SHIFT)
> +#define NFC_RANDOM_SEED (0x7fff << 16)
> +
> +
> +

Kill and avoid these extra empty lines.

> +enum sunxi_nand_rb_type {
> + RB_NONE,
> + RB_NATIVE,
> + RB_GPIO,
> +};
> +

Can you add some documentation about this read-back stuff?
I know documenting is not a super-fun activity, but it's a bit tough
to review otherwise.

> +struct sunxi_nand_rb {
> + enum sunxi_nand_rb_type type;
> + union {
> + int gpio;
> + int nativeid;
> + } info;
> +};
> +
> +struct sunxi_nand_chip_sel {
> + u8 cs;
> + struct sunxi_nand_rb rb;
> +};
> +
> +#define DEFAULT_NAME_FORMAT "nand@%d"
> +#define MAX_NAME_SIZE (sizeof("nand@") + 2)
> +
> +struct sunxi_nand_hw_ecc {
> + int mode;
> + struct nand_ecclayout layout;
> +};
> +
> +struct sunxi_nand_chip {
> + struct list_head node;
> + struct nand_chip nand;
> + struct mtd_info mtd;
> + char default_name[MAX_NAME_SIZE];
> + unsigned long clk_rate;
> + int selected;
> + int nsels;
> + struct sunxi_nand_chip_sel sels[0];

Hm... you prepare the whole multiple chip support but you really support a
single chip? I'd say drop entirely and support just a single chip, it'll
make the driver much cleaner. We can always add the support later, after
proper testing.

> +};
> +
> +static inline struct sunxi_nand_chip *to_sunxi_nand(struct nand_chip *nand)
> +{
> + return container_of(nand, struct sunxi_nand_chip, nand);
> +}
> +
> +struct sunxi_nfc {
> + struct nand_hw_control controller;
> + void __iomem *regs;
> + int irq;

You don't seem to need the irq stored anywhere, as you're using
devm_request_irq.

> + struct clk *ahb_clk;
> + struct clk *sclk;
> + unsigned long assigned_cs;
> + unsigned long clk_rate;
> + struct list_head chips;
> + struct completion complete;
> +};
> +
> +static inline struct sunxi_nfc *to_sunxi_nfc(struct nand_hw_control *ctrl)
> +{
> + return container_of(ctrl, struct sunxi_nfc, controller);
> +}
> +
> +static irqreturn_t sunxi_nfc_interrupt(int irq, void *dev_id)
> +{
> + struct sunxi_nfc *nfc = dev_id;
> + u32 st = readl(nfc->regs + NFC_REG_ST);
> + u32 ien = readl(nfc->regs + NFC_REG_INT);
> +
> + if (!(ien & st))
> + return IRQ_NONE;
> +
> + if ((ien & st) == ien)
> + complete(&nfc->complete);
> +
> + writel(st & NFC_INT_MASK, nfc->regs + NFC_REG_ST);
> + writel(~st & ien & NFC_INT_MASK, nfc->regs + NFC_REG_INT);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int sunxi_nfc_wait_int(struct sunxi_nfc *nfc, u32 flags,
> + unsigned int timeout_ms)
> +{
> + init_completion(&nfc->complete);
> +
> + writel(flags, nfc->regs + NFC_REG_INT);
> + if (!timeout_ms)
> + wait_for_completion(&nfc->complete);

In the same vein as infinite loops (see below), I'd avoid this no-timeout wait.
Or maybe you can *guarantee* it'll be always completed?

> + else if (!wait_for_completion_timeout(&nfc->complete,
> + msecs_to_jiffies(timeout_ms)))
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int sunxi_nfc_dev_ready(struct mtd_info *mtd)
> +{
> + struct nand_chip *nand = mtd->priv;
> + struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
> + struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> + struct sunxi_nand_rb *rb;
> + unsigned long timeo = (sunxi_nand->nand.state == FL_ERASING ? 400 : 20);
> + int ret;
> +
> + if (sunxi_nand->selected < 0)
> + return 0;
> +
> + rb = &sunxi_nand->sels[sunxi_nand->selected].rb;
> +
> + switch (rb->type) {
> + case RB_NATIVE:
> + ret = !!(readl(nfc->regs + NFC_REG_ST) &
> + (NFC_RB_STATE0 << rb->info.nativeid));
> + if (ret)
> + break;
> +
> + sunxi_nfc_wait_int(nfc, NFC_RB_B2R, timeo);
> + ret = !!(readl(nfc->regs + NFC_REG_ST) &
> + (NFC_RB_STATE0 << rb->info.nativeid));
> + break;
> + case RB_GPIO:
> + ret = gpio_get_value(rb->info.gpio);
> + break;
> + case RB_NONE:
> + default:
> + ret = 0;
> + pr_err("cannot check R/B NAND status!");

I'd suggest avoiding this kind of pr_err. The user won't know
who's saying this. Try using dev_err or pr_fmt.

> + break;
> + }
> +
> + return ret;
> +}
> +
> +static void sunxi_nfc_select_chip(struct mtd_info *mtd, int chip)
> +{
> + struct nand_chip *nand = mtd->priv;
> + struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
> + struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> + struct sunxi_nand_chip_sel *sel;
> + u32 ctl;
> +
> + if (chip > 0 && chip >= sunxi_nand->nsels)
> + return;
> +
> + if (chip == sunxi_nand->selected)
> + return;
> +
> + ctl = readl(nfc->regs + NFC_REG_CTL) &
> + ~(NFC_CE_SEL | NFC_RB_SEL | NFC_EN);
> +
> + if (chip >= 0) {
> + sel = &sunxi_nand->sels[chip];
> +
> + ctl |= (sel->cs << 24) | NFC_EN |
> + (((nand->page_shift - 10) & 0xf) << 8);
> + if (sel->rb.type == RB_NONE) {
> + nand->dev_ready = NULL;
> + } else {
> + nand->dev_ready = sunxi_nfc_dev_ready;
> + if (sel->rb.type == RB_NATIVE)
> + ctl |= (sel->rb.info.nativeid << 3);
> + }
> +
> + writel(mtd->writesize, nfc->regs + NFC_REG_SPARE_AREA);
> +
> + if (nfc->clk_rate != sunxi_nand->clk_rate) {
> + clk_set_rate(nfc->sclk, sunxi_nand->clk_rate);
> + nfc->clk_rate = sunxi_nand->clk_rate;
> + }
> + }
> +
> + writel(ctl, nfc->regs + NFC_REG_CTL);
> +
> + sunxi_nand->selected = chip;
> +}
> +
> +static void sunxi_nfc_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> +{
> + struct nand_chip *nand = mtd->priv;
> + struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
> + struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> + int cnt;
> + int offs = 0;
> + u32 tmp;
> +
> + while (len > offs) {
> + cnt = len - offs;
> + if (cnt > 1024)
> + cnt = 1024;
> +
> + while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> + ;

How about avoiding the infinite loop?

> + writel(cnt, nfc->regs + NFC_REG_CNT);
> + tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD;
> + writel(tmp, nfc->regs + NFC_REG_CMD);
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> + if (buf)
> + memcpy_fromio(buf + offs, nfc->regs + NFC_RAM0_BASE,
> + cnt);
> + offs += cnt;
> + }
> +}
> +
> +static void sunxi_nfc_write_buf(struct mtd_info *mtd, const uint8_t *buf,
> + int len)
> +{
> + struct nand_chip *nand = mtd->priv;
> + struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
> + struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> + int cnt;
> + int offs = 0;
> + u32 tmp;
> +
> + while (len > offs) {
> + cnt = len - offs;
> + if (cnt > 1024)
> + cnt = 1024;
> +
> + while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> + ;

Ditto.

> + writel(cnt, nfc->regs + NFC_REG_CNT);
> + memcpy_toio(nfc->regs + NFC_RAM0_BASE, buf + offs, cnt);
> + tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD |
> + NFC_ACCESS_DIR;
> + writel(tmp, nfc->regs + NFC_REG_CMD);
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> + offs += cnt;
> + }
> +}
> +
> +static uint8_t sunxi_nfc_read_byte(struct mtd_info *mtd)
> +{
> + uint8_t ret;
> +
> + sunxi_nfc_read_buf(mtd, &ret, 1);
> +
> + return ret;
> +}
> +
> +static void sunxi_nfc_cmd_ctrl(struct mtd_info *mtd, int dat,
> + unsigned int ctrl)
> +{
> + struct nand_chip *nand = mtd->priv;
> + struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(nand);
> + struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> + u32 tmp;
> +
> + while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> + ;
> +

Ditto.

> + if (ctrl & NAND_CTRL_CHANGE) {
> + tmp = readl(nfc->regs + NFC_REG_CTL);
> + if (ctrl & NAND_NCE)
> + tmp |= NFC_CE_CTL;
> + else
> + tmp &= ~NFC_CE_CTL;
> + writel(tmp, nfc->regs + NFC_REG_CTL);
> + }
> +
> + if (dat == NAND_CMD_NONE)
> + return;
> +
> + if (ctrl & NAND_CLE) {
> + writel(NFC_SEND_CMD1 | dat, nfc->regs + NFC_REG_CMD);
> + } else {
> + writel(dat, nfc->regs + NFC_REG_ADDR_LOW);
> + writel(NFC_SEND_ADR, nfc->regs + NFC_REG_CMD);
> + }
> +
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> +}
> +
> +static int sunxi_nfc_hw_ecc_read_page(struct mtd_info *mtd,
> + struct nand_chip *chip, uint8_t *buf,
> + int oob_required, int page)
> +{
> + struct sunxi_nfc *nfc = to_sunxi_nfc(chip->controller);
> + struct nand_ecc_ctrl *ecc = &chip->ecc;
> + struct nand_ecclayout *layout = ecc->layout;
> + struct sunxi_nand_hw_ecc *data = ecc->priv;
> + int steps = mtd->writesize / ecc->size;
> + unsigned int max_bitflips = 0;
> + int offset;
> + u32 tmp;
> + int i;
> + int cnt;
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~(NFC_ECC_MODE | NFC_ECC_PIPELINE | NFC_ECC_BLOCK_SIZE |
> + NFC_ECC_BLOCK_SIZE);
> + tmp |= NFC_ECC_EN | (data->mode << NFC_ECC_MODE_SHIFT);
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + for (i = 0; i < steps; i++) {
> + if (i)
> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, i * ecc->size, -1);
> +
> + offset = mtd->writesize + layout->eccpos[i * ecc->bytes] - 4;
> +
> + chip->read_buf(mtd, NULL, ecc->size);
> +
> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, offset, -1);
> + while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> + ;
> +

Ditto.

> + tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | (1 << 30);
> + writel(tmp, nfc->regs + NFC_REG_CMD);
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> + memcpy_fromio(buf + (i * ecc->size),
> + nfc->regs + NFC_RAM0_BASE, ecc->size);
> +
> + if (readl(nfc->regs + NFC_REG_ECC_ST) & 0x1) {
> + mtd->ecc_stats.failed++;
> + } else {
> + tmp = readl(nfc->regs + NFC_REG_ECC_CNT0) & 0xff;
> + mtd->ecc_stats.corrected += tmp;
> + max_bitflips = max_t(unsigned int, max_bitflips, tmp);
> + }
> +
> + if (oob_required) {
> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, offset, -1);
> + while ((readl(nfc->regs + NFC_REG_ST) &
> + NFC_CMD_FIFO_STATUS))
> + ;

Ditto.

> + offset -= mtd->writesize;
> + chip->read_buf(mtd, chip->oob_poi + offset,
> + ecc->bytes + 4);
> + }
> + }
> +
> + if (oob_required) {
> + cnt = ecc->layout->oobfree[0].length - 4;
> + if (cnt > 0) {
> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize,
> + -1);
> + chip->read_buf(mtd, chip->oob_poi, cnt);
> + }
> + }
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~NFC_ECC_EN;
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + return max_bitflips;
> +}
> +
> +static int sunxi_nfc_hw_ecc_write_page(struct mtd_info *mtd,
> + struct nand_chip *chip,
> + const uint8_t *buf, int oob_required)
> +{
> + struct sunxi_nfc *nfc = to_sunxi_nfc(chip->controller);
> + struct nand_ecc_ctrl *ecc = &chip->ecc;
> + struct nand_ecclayout *layout = ecc->layout;
> + struct sunxi_nand_hw_ecc *data = ecc->priv;
> + int offset;
> + u32 tmp;
> + int i;
> + int cnt;
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~(NFC_ECC_MODE | NFC_ECC_PIPELINE | NFC_ECC_BLOCK_SIZE |
> + NFC_ECC_BLOCK_SIZE);
> + tmp |= NFC_ECC_EN | (data->mode << NFC_ECC_MODE_SHIFT);
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + for (i = 0; i < mtd->writesize / ecc->size; i++) {
> + if (i)
> + chip->cmdfunc(mtd, NAND_CMD_RNDIN, i * ecc->size, -1);
> +
> + chip->write_buf(mtd, buf + (i * ecc->size), ecc->size);
> +
> + offset = layout->eccpos[i * ecc->bytes] - 4 + mtd->writesize;
> +
> + /* Fill OOB data in */
> + if (oob_required) {
> + tmp = 0xffffffff;
> + memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, &tmp,
> + 4);
> + } else {
> + memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE,
> + chip->oob_poi + offset - mtd->writesize,
> + 4);
> + }
> +
> + chip->cmdfunc(mtd, NAND_CMD_RNDIN, offset, -1);
> + while ((readl(nfc->regs + NFC_REG_ST) &
> + NFC_CMD_FIFO_STATUS))
> + ;
> +

Ditto.

> + tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | NFC_ACCESS_DIR |
> + (1 << 30);
> + writel(tmp, nfc->regs + NFC_REG_CMD);
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> + }
> +
> + if (oob_required) {
> + cnt = ecc->layout->oobfree[0].length - 4;
> + if (cnt > 0) {
> + chip->cmdfunc(mtd, NAND_CMD_RNDIN, mtd->writesize, -1);
> + chip->write_buf(mtd, chip->oob_poi, cnt);
> + }
> + }
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~(NFC_ECC_EN | NFC_ECC_PIPELINE);
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + return 0;
> +}
> +
> +static int sunxi_nfc_hw_syndrome_ecc_read_page(struct mtd_info *mtd,
> + struct nand_chip *chip,
> + uint8_t *buf, int oob_required,
> + int page)
> +{
> + struct sunxi_nfc *nfc = to_sunxi_nfc(chip->controller);
> + struct nand_ecc_ctrl *ecc = &chip->ecc;
> + struct sunxi_nand_hw_ecc *data = ecc->priv;
> + int steps = mtd->writesize / ecc->size;
> + unsigned int max_bitflips = 0;
> + uint8_t *oob = chip->oob_poi;
> + int offset = 0;
> + int cnt;
> + u32 tmp;
> + int i;
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~(NFC_ECC_MODE | NFC_ECC_PIPELINE | NFC_ECC_BLOCK_SIZE |
> + NFC_ECC_BLOCK_SIZE);
> + tmp |= NFC_ECC_EN | (data->mode << NFC_ECC_MODE_SHIFT);
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + for (i = 0; i < steps; i++) {
> + chip->read_buf(mtd, NULL, ecc->size);
> +
> + tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | (1 << 30);
> + writel(tmp, nfc->regs + NFC_REG_CMD);
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> + memcpy_fromio(buf, nfc->regs + NFC_RAM0_BASE, ecc->size);
> + buf += ecc->size;
> + offset += ecc->size;
> +
> + if (readl(nfc->regs + NFC_REG_ECC_ST) & 0x1) {
> + mtd->ecc_stats.failed++;
> + } else {
> + tmp = readl(nfc->regs + NFC_REG_ECC_CNT0) & 0xff;
> + mtd->ecc_stats.corrected += tmp;
> + max_bitflips = max_t(unsigned int, max_bitflips, tmp);
> + }
> +
> + if (oob_required) {
> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, offset, -1);
> + chip->read_buf(mtd, oob, ecc->bytes + ecc->prepad);
> + oob += ecc->bytes + ecc->prepad;
> + }
> +
> + offset += ecc->bytes + ecc->prepad;
> + }
> +
> + if (oob_required) {
> + cnt = mtd->oobsize - (oob - chip->oob_poi);
> + if (cnt > 0) {
> + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, offset, -1);
> + chip->read_buf(mtd, oob, cnt);
> + }
> + }
> +
> + writel(readl(nfc->regs + NFC_REG_ECC_CTL) & ~NFC_ECC_EN,
> + nfc->regs + NFC_REG_ECC_CTL);
> +
> + return max_bitflips;
> +}
> +
> +static int sunxi_nfc_hw_syndrome_ecc_write_page(struct mtd_info *mtd,
> + struct nand_chip *chip,
> + const uint8_t *buf,
> + int oob_required)
> +{
> + struct sunxi_nfc *nfc = to_sunxi_nfc(chip->controller);
> + struct nand_ecc_ctrl *ecc = &chip->ecc;
> + struct sunxi_nand_hw_ecc *data = ecc->priv;
> + int steps = mtd->writesize / ecc->size;
> + uint8_t *oob = chip->oob_poi;
> + int offset = 0;
> + int cnt;
> + u32 tmp;
> + int i;
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~(NFC_ECC_MODE | NFC_ECC_PIPELINE | NFC_ECC_BLOCK_SIZE |
> + NFC_ECC_BLOCK_SIZE);
> + tmp |= NFC_ECC_EN | (data->mode << NFC_ECC_MODE_SHIFT);
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + for (i = 0; i < steps; i++) {
> + chip->write_buf(mtd, buf + (i * ecc->size), ecc->size);
> + offset += ecc->size;
> +
> + /* Fill OOB data in */
> + if (oob_required) {
> + tmp = 0xffffffff;
> + memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, &tmp,
> + 4);
> + } else {
> + memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, oob ,
> + 4);
> + }
> +
> + tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | NFC_ACCESS_DIR |
> + (1 << 30);
> + writel(tmp, nfc->regs + NFC_REG_CMD);
> + sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> +
> + offset += ecc->bytes + ecc->prepad;
> + oob += ecc->bytes + ecc->prepad;
> + }
> +
> + if (oob_required) {
> + cnt = mtd->oobsize - (oob - chip->oob_poi);
> + if (cnt > 0) {
> + chip->cmdfunc(mtd, NAND_CMD_RNDIN, offset, -1);
> + chip->write_buf(mtd, oob, cnt);
> + }
> + }
> +
> + tmp = readl(nfc->regs + NFC_REG_ECC_CTL);
> + tmp &= ~(NFC_ECC_EN | NFC_ECC_PIPELINE);
> +
> + writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
> +
> + return 0;
> +}
> +
> +static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip,
> + const struct nand_sdr_timings *timings)
> +{
> + u32 min_clk_period = 0;
> +
> + /* T1 <=> tCLS */
> + if (timings->tCLS_min > min_clk_period)
> + min_clk_period = timings->tCLS_min;
> +
> + /* T2 <=> tCLH */
> + if (timings->tCLH_min > min_clk_period)
> + min_clk_period = timings->tCLH_min;
> +
> + /* T3 <=> tCS */
> + if (timings->tCS_min > min_clk_period)
> + min_clk_period = timings->tCS_min;
> +
> + /* T4 <=> tCH */
> + if (timings->tCH_min > min_clk_period)
> + min_clk_period = timings->tCH_min;
> +
> + /* T5 <=> tWP */
> + if (timings->tWP_min > min_clk_period)
> + min_clk_period = timings->tWP_min;
> +
> + /* T6 <=> tWH */
> + if (timings->tWH_min > min_clk_period)
> + min_clk_period = timings->tWH_min;
> +
> + /* T7 <=> tALS */
> + if (timings->tALS_min > min_clk_period)
> + min_clk_period = timings->tALS_min;
> +
> + /* T8 <=> tDS */
> + if (timings->tDS_min > min_clk_period)
> + min_clk_period = timings->tDS_min;
> +
> + /* T9 <=> tDH */
> + if (timings->tDH_min > min_clk_period)
> + min_clk_period = timings->tDH_min;
> +
> + /* T10 <=> tRR */
> + if (timings->tRR_min > (min_clk_period * 3))
> + min_clk_period = (timings->tRR_min + 2) / 3;
> +
> + /* T11 <=> tALH */
> + if (timings->tALH_min > min_clk_period)
> + min_clk_period = timings->tALH_min;
> +
> + /* T12 <=> tRP */
> + if (timings->tRP_min > min_clk_period)
> + min_clk_period = timings->tRP_min;
> +
> + /* T13 <=> tREH */
> + if (timings->tREH_min > min_clk_period)
> + min_clk_period = timings->tREH_min;
> +
> + /* T14 <=> tRC */
> + if (timings->tRC_min > (min_clk_period * 2))
> + min_clk_period = (timings->tRC_min + 1) / 2;
> +
> + /* T15 <=> tWC */
> + if (timings->tWC_min > (min_clk_period * 2))
> + min_clk_period = (timings->tWC_min + 1) / 2;
> +
> +
> + /* min_clk_period = (NAND-clk-period * 2) */
> + if (min_clk_period < 1000)
> + min_clk_period = 1000;
> +
> + min_clk_period /= 1000;
> + chip->clk_rate = (2 * 1000000000) / min_clk_period;
> +
> + /* TODO: configure T16-T19 */
> +
> + return 0;
> +}
> +
> +static int sunxi_nand_chip_init_timings(struct sunxi_nand_chip *chip,
> + struct device_node *np)
> +{
> + const struct nand_sdr_timings *timings;
> + int ret;
> + int mode;
> +
> + mode = onfi_get_async_timing_mode(&chip->nand);
> + if (mode == ONFI_TIMING_MODE_UNKNOWN) {
> + mode = of_get_nand_onfi_timing_mode(np);
> + if (mode < 0)
> + mode = 1;
> +
> + mode = fls(mode) - 1;
> + if (mode < 0)
> + mode = 0;
> + } else {
> + uint8_t feature[ONFI_SUBFEATURE_PARAM_LEN] = {};
> + mode = fls(mode) - 1;
> + if (mode < 0)
> + mode = 0;
> +
> + feature[0] = mode;
> + ret = chip->nand.onfi_set_features(&chip->mtd, &chip->nand,
> + ONFI_FEATURE_ADDR_TIMING_MODE,
> + feature);
> + if (ret)
> + return ret;
> + }
> +
> + timings = onfi_async_timing_mode_to_sdr_timings(mode);
> + if (IS_ERR(timings))
> + return PTR_ERR(timings);
> +
> + return sunxi_nand_chip_set_timings(chip, timings);
> +}
> +
> +static int sunxi_nand_hw_common_ecc_ctrl_init(struct mtd_info *mtd,
> + struct nand_ecc_ctrl *ecc,
> + struct device_node *np)
> +{
> + struct sunxi_nand_hw_ecc *data;
> + struct nand_ecclayout *layout;
> + int nsectors;
> + int ret;
> +
> + if (!ecc->strength || !ecc->size)
> + return -EINVAL;
> +
> + data = kzalloc(sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + /* Add ECC info retrieval from DT */
> + if (ecc->strength <= 16) {
> + ecc->strength = 16;
> + data->mode = 0;
> + } else if (ecc->strength <= 24) {
> + ecc->strength = 24;
> + data->mode = 1;
> + } else if (ecc->strength <= 28) {
> + ecc->strength = 28;
> + data->mode = 2;
> + } else if (ecc->strength <= 32) {
> + ecc->strength = 32;
> + data->mode = 3;
> + } else if (ecc->strength <= 40) {
> + ecc->strength = 40;
> + data->mode = 4;
> + } else if (ecc->strength <= 48) {
> + ecc->strength = 48;
> + data->mode = 5;
> + } else if (ecc->strength <= 56) {
> + ecc->strength = 56;
> + data->mode = 6;
> + } else if (ecc->strength <= 60) {
> + ecc->strength = 60;
> + data->mode = 7;
> + } else if (ecc->strength <= 64) {
> + ecc->strength = 64;
> + data->mode = 8;
> + } else {
> + pr_err("unsupported strength\n");

> + return -ENOTSUPP;

You're leaking the 'data' allocated above in here.

> + }
> +
> + /* HW ECC always request ECC bytes for 1024 bytes blocks */
> + ecc->bytes = ((ecc->strength * fls(8 * 1024)) + 7) / 8;
> +
> + /* HW ECC always work with even numbers of ECC bytes */
> + if (ecc->bytes % 2)
> + ecc->bytes++;
> +
> + layout = &data->layout;
> + nsectors = mtd->writesize / ecc->size;
> +
> + if (mtd->oobsize < ((ecc->bytes + 4) * nsectors)) {
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + layout->eccbytes = (ecc->bytes * nsectors);
> +
> + ecc->layout = layout;
> + ecc->priv = data;
> +
> + return 0;
> +
> +err:
> + kfree(data);
> +
> + return ret;
> +}
> +
> +static void sunxi_nand_hw_common_ecc_ctrl_cleanup(struct nand_ecc_ctrl *ecc)
> +{
> + kfree(ecc->priv);
> +}
> +
> +static int sunxi_nand_hw_ecc_ctrl_init(struct mtd_info *mtd,
> + struct nand_ecc_ctrl *ecc,
> + struct device_node *np)
> +{
> + struct nand_ecclayout *layout;
> + int nsectors;
> + int i, j;
> + int ret;
> +
> + ret = sunxi_nand_hw_common_ecc_ctrl_init(mtd, ecc, np);
> + if (ret)
> + return ret;
> +
> + ecc->read_page = sunxi_nfc_hw_ecc_read_page;
> + ecc->write_page = sunxi_nfc_hw_ecc_write_page;
> + layout = ecc->layout;
> + nsectors = mtd->writesize / ecc->size;
> + /*
> + * The first 2 bytes are used for BB markers.
> + * We merge the 4 user available bytes from HW ECC with this
> + * first section, hence why the + 2 operation (- 2 + 4).
> + */
> + layout->oobfree[0].length = mtd->oobsize + 2 -
> + ((ecc->bytes + 4) * nsectors);
> + layout->oobfree[0].offset = 2;
> + for (i = 0; i < nsectors; i++) {
> + /*
> + * The first 4 ECC block bytes are already counted in the first
> + * oobfree entry.
> + */
> + if (i) {
> + layout->oobfree[i].offset =
> + layout->oobfree[i - 1].offset +
> + layout->oobfree[i - 1].length +
> + ecc->bytes;
> + layout->oobfree[i].length = 4;
> + }
> +
> + for (j = 0; j < ecc->bytes; j++)
> + layout->eccpos[(ecc->bytes * i) + j] =
> + layout->oobfree[i].offset +
> + layout->oobfree[i].length + j;
> + }
> +
> + return 0;
> +}
> +
> +static int sunxi_nand_hw_syndrome_ecc_ctrl_init(struct mtd_info *mtd,
> + struct nand_ecc_ctrl *ecc,
> + struct device_node *np)
> +{
> + struct nand_ecclayout *layout;
> + int nsectors;
> + int i;
> + int ret;
> +
> + ret = sunxi_nand_hw_common_ecc_ctrl_init(mtd, ecc, np);
> + if (ret)
> + return ret;
> +
> + ecc->prepad = 4;
> + ecc->read_page = sunxi_nfc_hw_syndrome_ecc_read_page;
> + ecc->write_page = sunxi_nfc_hw_syndrome_ecc_write_page;
> +
> + layout = ecc->layout;
> + nsectors = mtd->writesize / ecc->size;
> +
> + for (i = 0; i < (ecc->bytes * nsectors); i++)
> + layout->eccpos[i] = i;
> +
> + layout->oobfree[0].length = mtd->oobsize - i;
> + layout->oobfree[0].offset = i;
> +
> + return 0;
> +}
> +
> +static void sunxi_nand_ecc_cleanup(struct nand_ecc_ctrl *ecc)
> +{
> + switch (ecc->mode) {
> + case NAND_ECC_HW:
> + case NAND_ECC_HW_SYNDROME:
> + sunxi_nand_hw_common_ecc_ctrl_cleanup(ecc);
> + break;
> + default:
> + break;
> + }
> +}
> +
> +static int sunxi_nand_ecc_init(struct mtd_info *mtd, struct nand_ecc_ctrl *ecc,
> + struct device_node *np)
> +{
> + struct nand_chip *nand = mtd->priv;
> + int ecc_step_size, ecc_strength;
> + int ret;
> +
> + ecc_step_size = of_get_nand_ecc_step_size(np);
> + ecc_strength = of_get_nand_ecc_strength(np);
> + if (ecc_step_size > 0 && ecc_strength > 0) {
> + ecc->size = ecc_step_size;
> + ecc->strength = ecc_strength;
> + } else {
> + ecc->size = nand->ecc_step_ds;
> + ecc->strength = nand->ecc_strength_ds;
> + }
> +

Shouldn't you check the devicetree value is not weaker than the ONFI-obtained?

> + ecc->mode = of_get_nand_ecc_mode(np);
> + switch (ecc->mode) {
> + case NAND_ECC_SOFT_BCH:
> + if (!ecc->size || !ecc->strength)
> + return -EINVAL;
> + ecc->bytes = ((ecc->strength * fls(8 * ecc->size)) + 7) / 8;
> + break;
> + case NAND_ECC_HW:
> + ret = sunxi_nand_hw_ecc_ctrl_init(mtd, ecc, np);
> + if (ret)
> + return ret;
> + break;
> + case NAND_ECC_HW_SYNDROME:
> + ret = sunxi_nand_hw_syndrome_ecc_ctrl_init(mtd, ecc, np);
> + if (ret)
> + return ret;
> + break;
> + case NAND_ECC_NONE:
> + case NAND_ECC_SOFT:
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
> + struct device_node *np)
> +{
> + const struct nand_sdr_timings *timings;
> + struct sunxi_nand_chip *chip;
> + struct mtd_part_parser_data ppdata;
> + struct mtd_info *mtd;
> + struct nand_chip *nand;
> + int nsels;
> + int ret;
> + int i;
> + u32 tmp;
> +
> + if (!of_get_property(np, "reg", &nsels))
> + return -EINVAL;
> +
> + nsels /= sizeof(u32);
> + if (!nsels)
> + return -EINVAL;
> +
> + chip = devm_kzalloc(dev,
> + sizeof(*chip) +
> + (nsels * sizeof(struct sunxi_nand_chip_sel)),
> + GFP_KERNEL);
> + if (!chip)
> + return -ENOMEM;
> +
> + chip->nsels = nsels;
> + chip->selected = -1;
> +
> + for (i = 0; i < nsels; i++) {
> + ret = of_property_read_u32_index(np, "reg", i, &tmp);
> + if (ret)
> + return ret;
> +
> + if (tmp > 7)
> + return -EINVAL;
> +
> + if (test_and_set_bit(tmp, &nfc->assigned_cs))
> + return -EINVAL;
> +
> + chip->sels[i].cs = tmp;
> +
> + if (!of_property_read_u32_index(np, "allwinner,rb", i, &tmp) &&
> + tmp < 2) {
> + chip->sels[i].rb.type = RB_NATIVE;
> + chip->sels[i].rb.info.nativeid = tmp;
> + } else {
> + ret = of_get_named_gpio(np, "rb-gpios", i);
> + if (ret >= 0) {
> + tmp = ret;
> + chip->sels[i].rb.type = RB_GPIO;
> + chip->sels[i].rb.info.gpio = tmp;
> + ret = devm_gpio_request(dev, tmp, "nand-rb");
> + if (ret)
> + return ret;
> +
> + ret = gpio_direction_input(tmp);
> + if (ret)
> + return ret;
> + } else {
> + chip->sels[i].rb.type = RB_NONE;
> + }
> + }
> + }
> +
> + timings = onfi_async_timing_mode_to_sdr_timings(0);
> + if (IS_ERR(timings))
> + return PTR_ERR(timings);
> +
> + ret = sunxi_nand_chip_set_timings(chip, timings);
> +
> + nand = &chip->nand;
> + /* Default tR value specified in the ONFI spec (chapter 4.15.1) */
> + nand->chip_delay = 200;
> + nand->controller = &nfc->controller;
> + nand->select_chip = sunxi_nfc_select_chip;
> + nand->cmd_ctrl = sunxi_nfc_cmd_ctrl;
> + nand->read_buf = sunxi_nfc_read_buf;
> + nand->write_buf = sunxi_nfc_write_buf;
> + nand->read_byte = sunxi_nfc_read_byte;
> +
> + if (of_get_nand_on_flash_bbt(np))
> + nand->bbt_options |= NAND_BBT_USE_FLASH;
> +
> + mtd = &chip->mtd;
> + mtd->dev.parent = dev;
> + mtd->priv = nand;
> + mtd->owner = THIS_MODULE;
> +
> + ret = nand_scan_ident(mtd, nsels, NULL);
> + if (ret)
> + return ret;
> +
> + ret = sunxi_nand_chip_init_timings(chip, np);
> + if (ret)
> + return ret;
> +
> + ret = sunxi_nand_ecc_init(mtd, &nand->ecc, np);
> + if (ret)
> + return ret;
> +
> + ret = nand_scan_tail(mtd);
> + if (ret)
> + return ret;
> +
> + if (of_property_read_string(np, "nand-name", &mtd->name)) {
> + snprintf(chip->default_name, MAX_NAME_SIZE,
> + DEFAULT_NAME_FORMAT, chip->sels[i].cs);
> + mtd->name = chip->default_name;
> + }
> +
> + ppdata.of_node = np;
> + ret = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
> + if (!ret)

Aren't you leaking the BBT resources allocated in nand_scan_tail? I **think**
you need to call nand_release if the mtd device register fails.

> + return ret;
> +
> + list_add_tail(&chip->node, &nfc->chips);
> +
> + return 0;
> +}
> +
> +static int sunxi_nand_chips_init(struct device *dev, struct sunxi_nfc *nfc)
> +{
> + struct device_node *np = dev->of_node;
> + struct device_node *nand_np;
> + int nchips = of_get_child_count(np);
> + int ret;
> +
> + if (nchips > 8)
> + return -EINVAL;
> +
> + for_each_child_of_node(np, nand_np) {
> + ret = sunxi_nand_chip_init(dev, nfc, nand_np);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void sunxi_nand_chips_cleanup(struct sunxi_nfc *nfc)
> +{
> + struct sunxi_nand_chip *chip;
> +
> + while (!list_empty(&nfc->chips)) {
> + chip = list_first_entry(&nfc->chips, struct sunxi_nand_chip,
> + node);
> + nand_release(&chip->mtd);
> + sunxi_nand_ecc_cleanup(&chip->nand.ecc);
> + }
> +}
> +
> +static int sunxi_nfc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct resource *r;
> + struct sunxi_nfc *nfc;
> + int ret;
> +
> + nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
> + if (!nfc) {
> + dev_err(dev, "failed to allocate NFC struct\n");

OOM message not needed.

> + return -ENOMEM;
> + }
> +
> + spin_lock_init(&nfc->controller.lock);
> + init_waitqueue_head(&nfc->controller.wq);
> + INIT_LIST_HEAD(&nfc->chips);
> +
> + r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + nfc->regs = devm_ioremap_resource(dev, r);
> + if (IS_ERR(nfc->regs)) {
> + dev_err(dev, "failed to remap iomem\n");

Message not needed, see devm_ioremap_resource() documentation.

> + return PTR_ERR(nfc->regs);
> + }
> +
> + nfc->irq = platform_get_irq(pdev, 0);
> + if (nfc->irq < 0) {
> + dev_err(dev, "failed to retrieve irq\n");
> + return nfc->irq;
> + }
> +
> + nfc->ahb_clk = devm_clk_get(dev, "ahb_clk");
> + if (IS_ERR(nfc->ahb_clk)) {
> + dev_err(dev, "failed to retrieve ahb_clk\n");
> + return PTR_ERR(nfc->ahb_clk);
> + }
> +
> + ret = clk_prepare_enable(nfc->ahb_clk);
> + if (ret)
> + return ret;
> +
> + nfc->sclk = devm_clk_get(dev, "sclk");
> + if (IS_ERR(nfc->sclk)) {
> + dev_err(dev, "failed to retrieve nand_clk\n");
> + ret = PTR_ERR(nfc->sclk);
> + goto out_ahb_clk_unprepare;
> + }
> +
> + ret = clk_prepare_enable(nfc->sclk);
> + if (ret)
> + goto out_ahb_clk_unprepare;
> +
> + /* Reset NFC */
> + writel(readl(nfc->regs + NFC_REG_CTL) | NFC_RESET,
> + nfc->regs + NFC_REG_CTL);
> + while (readl(nfc->regs + NFC_REG_CTL) & NFC_RESET)
> + ;

Again: maybe you should avoid potentially infinite loop, no matter what.

> +
> + writel(0, nfc->regs + NFC_REG_INT);
> + ret = devm_request_irq(dev, nfc->irq, sunxi_nfc_interrupt,
> + 0, "sunxi-nand", nfc);
> + if (ret)
> + goto out_sclk_unprepare;
> +
> + platform_set_drvdata(pdev, nfc);
> +
> + writel(0x100, nfc->regs + NFC_REG_TIMING_CTL);
> + writel(0x7ff, nfc->regs + NFC_REG_TIMING_CFG);

Hm... can you remove the magic numbers?

> +
> + ret = sunxi_nand_chips_init(dev, nfc);
> + if (ret) {
> + dev_err(dev, "failed to init nand chips\n");
> + goto out_sclk_unprepare;
> + }
> +
> + return 0;
> +
> +out_sclk_unprepare:
> + clk_disable_unprepare(nfc->sclk);
> +out_ahb_clk_unprepare:
> + clk_disable_unprepare(nfc->ahb_clk);
> +
> + return ret;
> +}
> +
> +static int sunxi_nfc_remove(struct platform_device *pdev)
> +{
> + struct sunxi_nfc *nfc = platform_get_drvdata(pdev);
> +
> + sunxi_nand_chips_cleanup(nfc);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id sunxi_nfc_ids[] = {
> + { .compatible = "allwinner,sun4i-nand" },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sunxi_nfc_ids);
> +
> +static struct platform_driver sunxi_nfc_driver = {
> + .driver = {
> + .name = "sunxi_nand",
> + .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(sunxi_nfc_ids),

Redundant of_match_ptr. See 5576bc7bef2919dd2b185bffb768bf9c0da76788.

I think that's all I can spot, without knowing the hardware details.
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering