Re: [RFC PATCH 5/9] mtd: nand: add sunxi NFC support

[boris brezillon <b.brezillon@overkiz.com>]

Le 08/01/2014 15:22, Boris BREZILLON a écrit :
> Add the sunxi NAND Flash Controller driver.
>
> Signed-off-by: Boris BREZILLON <b.brezillon@overkiz.com>
> ---
>   drivers/mtd/nand/Kconfig     |    6 +
>   drivers/mtd/nand/Makefile    |    1 +
>   drivers/mtd/nand/sunxi_nfc.c |  700 ++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 707 insertions(+)
>   create mode 100644 drivers/mtd/nand/sunxi_nfc.c
>
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index 93ae6a6..784dd42 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 542b568..e8b210d 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_nfc.o
>   

BTW, I recently was one of the sources of a merge issue in the clk
subsystem because of unsorted Makefile lines.
Shouldn't we try to sort this Makefile too ?

>   nand-objs := nand_base.o nand_bbt.o
> diff --git a/drivers/mtd/nand/sunxi_nfc.c b/drivers/mtd/nand/sunxi_nfc.c
> new file mode 100644
> index 0000000..1c7a511
> --- /dev/null
> +++ b/drivers/mtd/nand/sunxi_nfc.c
> @@ -0,0 +1,700 @@
> +/*
> + * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
> + *
> + * Derived from Qiang Yu work:
> + *	https://github.com/yuq/sunxi-nfc-mtd
> + *	Copyright (C) 2013 Qiang Yu <yuq825@gmail.com>
> + *
> + * 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*/
> +#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)
> +
> +
> +
> +enum sunxi_nand_rb_type {
> +	RB_NONE,
> +	RB_NATIVE,
> +	RB_GPIO,
> +};
> +
> +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_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];
> +};
> +
> +static inline struct sunxi_nand_chip *to_sunxi_nand(struct mtd_info *mtd)
> +{
> +	return container_of(mtd, struct sunxi_nand_chip, mtd);
> +}
> +
> +struct sunxi_nfc {
> +	struct nand_hw_control controller;
> +	void __iomem *regs;
> +	int irq;
> +	struct clk *ahb_clk;
> +	struct clk *sclk;
> +	unsigned long assigned_cs;
> +	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);
> +	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 sunxi_nand_chip *sunxi_nand = to_sunxi_nand(mtd);
> +	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;
> +		dev_err(&mtd->dev, "cannot check R/B NAND status!");
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static void sunxi_nfc_select_chip(struct mtd_info *mtd, int chip)
> +{
> +	struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(mtd);
> +	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 |
> +		       (((sunxi_nand->nand.page_shift - 10) & 0xf) << 8);
> +		if (sel->rb.type == RB_NONE) {
> +			sunxi_nand->nand.dev_ready = NULL;
> +		} else {
> +			sunxi_nand->nand.dev_ready = sunxi_nfc_dev_ready;
> +			if (sel->rb.type == RB_NATIVE)
> +				ctl |= (sel->rb.info.nativeid << 3);
> +		}
> +	}
> +
> +	writel(ctl, nfc->regs + NFC_REG_CTL);
> +	clk_set_rate(nfc->sclk, sunxi_nand->clk_rate);
> +
> +	sunxi_nand->selected = chip;
> +}
> +
> +static void sunxi_nfc_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> +{
> +	struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(mtd);
> +	struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> +	int cnt;
> +	int offs = 0;
> +
> +	while (len > 0) {
> +		cnt = len > 1024 ? 1024 : len;
> +		while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> +			;
> +		writel(cnt, nfc->regs + NFC_REG_CNT);
> +		writel(NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | NFC_SEQ,
> +		       nfc->regs + NFC_REG_CMD);
> +		sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> +		memcpy_fromio(buf + offs, nfc->regs + NFC_RAM0_BASE, cnt);
> +		offs += cnt;
> +		len -= cnt;
> +	}
> +}
> +
> +static void sunxi_nfc_write_buf(struct mtd_info *mtd, const uint8_t *buf,
> +				int len)
> +{
> +	struct sunxi_nand_chip *sunxi_nand = to_sunxi_nand(mtd);
> +	struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> +	int cnt;
> +	int offs = 0;
> +
> +	while (len > 0) {
> +		cnt = len > 1024 ? 1024 : len;
> +		while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> +			;
> +		writel(cnt, nfc->regs + NFC_REG_CNT);
> +		memcpy_toio(nfc->regs + NFC_RAM0_BASE, buf + offs, cnt);
> +		writel(NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD |
> +		       NFC_ACCESS_DIR | NFC_SEQ, nfc->regs + NFC_REG_CMD);
> +		sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
> +		offs += cnt;
> +		len -= 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 sunxi_nand_chip *sunxi_nand = to_sunxi_nand(mtd);
> +	struct sunxi_nfc *nfc = to_sunxi_nfc(sunxi_nand->nand.controller);
> +	u32 tmp;
> +
> +	while ((readl(nfc->regs + NFC_REG_ST) & NFC_CMD_FIFO_STATUS))
> +		;
> +
> +	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_nand_chip_init_timings(struct sunxi_nand_chip *chip,
> +					struct device_node *np)
> +{
> +	struct nand_timings timings;
> +	u32 min_clk_period = 0;
> +	int ret;
> +
> +	ret = of_get_nand_timings(np, &timings);
> +	if (ret)
> +		return ret;
> +
> +	/* NFC timings defined in Allwinner Datasheets */
> +
> +	/* 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)
> +		chip->clk_rate = 20000000;
> +	else
> +		chip->clk_rate = (2 * 1000000000) / min_clk_period;
> +
> +	/* TODO: configure T16-T19 */
> +
> +	return 0;
> +}
> +
> +static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
> +				struct device_node *np)
> +{
> +	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) {
> +				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;
> +			} else {
> +				chip->sels[i].rb.type = RB_NONE;
> +			}
> +		}
> +	}
> +
> +	ret = sunxi_nand_chip_init_timings(chip, np);
> +	if (ret)
> +		return ret;
> +
> +	nand = &chip->nand;
> +	nand->IO_ADDR_R = nand->IO_ADDR_W = nfc->regs + NFC_REG_IO_DATA;
> +	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;
> +
> +	nand->ecc.mode = of_get_nand_ecc_mode(np);
> +	if (of_get_nand_on_flash_bbt(np))
> +		nand->bbt_options |= NAND_BBT_USE_FLASH;
> +
> +	mtd = &chip->mtd;
> +	mtd->priv = nand;
> +	mtd->owner = THIS_MODULE;
> +
> +	ret = nand_scan_ident(mtd, nsels, NULL);
> +	if (ret)
> +		return ret;
> +
> +	if (nand->ecc.mode == NAND_ECC_SOFT_BCH) {
> +		nand->ecc.size = nand->ecc_step_ds;
> +		nand->ecc.bytes = (((nand->ecc_strength_ds *
> +				     fls(8 * nand->ecc_step_ds)) + 7) / 8);
> +	}
> +
> +	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)
> +		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 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");
> +		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");
> +		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)
> +		;
> +
> +	writel(0, nfc->regs + NFC_REG_INT);
> +	ret = devm_request_irq(dev, nfc->irq, sunxi_nfc_interrupt,
> +			       0, "sunxi-nfc", 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);
> +
> +	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 const struct of_device_id sunxi_nfc_ids[] = {
> +	{ .compatible = "allwinner,sun4i-nfc" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sunxi_nfc_ids);
> +
> +static struct platform_driver sunxi_nfc_driver = {
> +	.driver = {
> +		.name = "sunxi_nfc",
> +		.owner = THIS_MODULE,
> +		.of_match_table = of_match_ptr(sunxi_nfc_ids),
> +	},
> +	.probe = sunxi_nfc_probe,
> +};
> +module_platform_driver(sunxi_nfc_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Boris BREZILLON");
> +MODULE_DESCRIPTION("Allwinner NAND Flash Controller driver");
> +MODULE_ALIAS("platform:sunxi_nfc");