Message-ID: <20150520204948.GL11598@ld-irv-0074>
Date:	Wed, 20 May 2015 13:49:48 -0700
From:	Brian Norris <computersforpeace@...il.com>
To:	Punnaiah Choudary Kalluri <punnaiah.choudary.kalluri@...inx.com>
Cc:	robh+dt@...nel.org, pawel.moll@....com, mark.rutland@....com,
	ijc+devicetree@...lion.org.uk, galak@...eaurora.org,
	rob@...dley.net, michal.simek@...inx.com, grant.likely@...aro.org,
	gregkh@...uxfoundation.org, jason@...edaemon.net,
	ezequiel.garcia@...e-electrons.com, arnd@...db.de,
	dwmw2@...radead.org, artem.bityutskiy@...ux.intel.com,
	jussi.kivilinna@....fi, acourbot@...dia.com, joern@...fs.org,
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-mtd@...ts.infradead.org,
	kpc528@...il.com, kalluripunnaiahchoudary@...il.com,
	Punnaiah Choudary Kalluri <punnaia@...inx.com>
Subject: Re: [PATCH v2 2/2] mtd: nand: Add support for Arasan Nand Flash
 Controller

On Tue, May 19, 2015 at 07:19:17PM +0530, Punnaiah Choudary Kalluri wrote:
> Added the basic driver for Arasan Nand Flash Controller used in
> Zynq UltraScale+ MPSoC. It supports only Hw Ecc and upto 24bit
> correction.
> 
> Signed-off-by: Punnaiah Choudary Kalluri <punnaia@...inx.com>
> Tested-by: Michal Simek <michal.simek@...inx.com>
> ---
> Changes in v2:
> - Added missing of.h to avoid kbuild system report error
> ---
>  drivers/mtd/nand/Kconfig      |    7 +
>  drivers/mtd/nand/Makefile     |    1 +
>  drivers/mtd/nand/arasan_nfc.c |  862 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 870 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/mtd/nand/arasan_nfc.c
> 
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index 5897d8d..64e497c 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -530,4 +530,11 @@ config MTD_NAND_HISI504
>  	help
>  	  Enables support for NAND controller on Hisilicon SoC Hip04.
>  
> +config MTD_NAND_ARASAN
> +	tristate "Support for Arasan Nand Flash controller"
> +	depends on MTD_NAND
> +	help
> +	  Enables the driver for the Arasan Nand Flash controller on
> +	  Zynq UltraScale+ MPSoC.
> +
>  endif # MTD_NAND
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index 582bbd05..fd863ea 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -52,5 +52,6 @@ obj-$(CONFIG_MTD_NAND_XWAY)		+= xway_nand.o
>  obj-$(CONFIG_MTD_NAND_BCM47XXNFLASH)	+= bcm47xxnflash/
>  obj-$(CONFIG_MTD_NAND_SUNXI)		+= sunxi_nand.o
>  obj-$(CONFIG_MTD_NAND_HISI504)	        += hisi504_nand.o
> +obj-$(CONFIG_MTD_NAND_ARASAN)		+= arasan_nfc.o
>  
>  nand-objs := nand_base.o nand_bbt.o nand_timings.o
> diff --git a/drivers/mtd/nand/arasan_nfc.c b/drivers/mtd/nand/arasan_nfc.c
> new file mode 100644
> index 0000000..5736864
> --- /dev/null
> +++ b/drivers/mtd/nand/arasan_nfc.c
> @@ -0,0 +1,862 @@
> +/*
> + * Arasan Nand Flash Controller Driver
> + *
> + * Copyright (C) 2014 - 2015 Xilinx, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify it under
> + * the terms of the GNU General Public License version 2 as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/nand.h>
> +#include <linux/mtd/partitions.h>
> +#include <linux/of.h>
> +#include <linux/of_mtd.h>
> +#include <linux/platform_device.h>
> +
> +#define DRIVER_NAME			"arasan_nfc"
> +#define EVNT_TIMEOUT			1000
> +#define STATUS_TIMEOUT			2000
> +
> +#define PKT_OFST			0x00
> +#define MEM_ADDR1_OFST			0x04
> +#define MEM_ADDR2_OFST			0x08
> +#define CMD_OFST			0x0C
> +#define PROG_OFST			0x10
> +#define INTR_STS_EN_OFST		0x14
> +#define INTR_SIG_EN_OFST		0x18
> +#define INTR_STS_OFST			0x1C
> +#define READY_STS_OFST			0x20
> +#define DMA_ADDR1_OFST			0x24
> +#define FLASH_STS_OFST			0x28
> +#define DATA_PORT_OFST			0x30
> +#define ECC_OFST			0x34
> +#define ECC_ERR_CNT_OFST		0x38
> +#define ECC_SPR_CMD_OFST		0x3C
> +#define ECC_ERR_CNT_1BIT_OFST		0x40
> +#define ECC_ERR_CNT_2BIT_OFST		0x44
> +#define DMA_ADDR0_OFST			0x50
> +
> +#define PKT_CNT_SHIFT			12
> +
> +#define ECC_ENABLE			BIT(31)
> +#define DMA_EN_MASK			GENMASK(27, 26)
> +#define DMA_ENABLE			0x2
> +#define DMA_EN_SHIFT			26
> +#define PAGE_SIZE_MASK			GENMASK(25, 23)
> +#define PAGE_SIZE_SHIFT			23
> +#define PAGE_SIZE_512			0
> +#define PAGE_SIZE_1K			5
> +#define PAGE_SIZE_2K			1
> +#define PAGE_SIZE_4K			2
> +#define PAGE_SIZE_8K			3
> +#define PAGE_SIZE_16K			4
> +#define CMD2_SHIFT			8
> +#define ADDR_CYCLES_SHIFT		28
> +
> +#define XFER_COMPLETE			BIT(2)
> +#define READ_READY			BIT(1)
> +#define WRITE_READY			BIT(0)
> +#define MBIT_ERROR			BIT(3)
> +#define ERR_INTRPT			BIT(4)
> +
> +#define PROG_PGRD			BIT(0)
> +#define PROG_ERASE			BIT(2)
> +#define PROG_STATUS			BIT(3)
> +#define PROG_PGPROG			BIT(4)
> +#define PROG_RDID			BIT(6)
> +#define PROG_RDPARAM			BIT(7)
> +#define PROG_RST			BIT(8)
> +
> +#define ONFI_STATUS_FAIL		BIT(0)
> +#define ONFI_STATUS_READY		BIT(6)
> +
> +#define PG_ADDR_SHIFT			16
> +#define BCH_MODE_SHIFT			25
> +#define BCH_EN_SHIFT			27
> +#define ECC_SIZE_SHIFT			16
> +
> +#define MEM_ADDR_MASK			GENMASK(7, 0)
> +#define BCH_MODE_MASK			GENMASK(27, 25)
> +
> +#define CS_MASK				GENMASK(31, 30)
> +#define CS_SHIFT			30
> +
> +#define PAGE_ERR_CNT_MASK		GENMASK(16, 8)
> +#define PKT_ERR_CNT_MASK		GENMASK(7, 0)
> +
> +#define ONFI_ID_LEN			8
> +#define TEMP_BUF_SIZE			512
> +
> +/**
> + * struct anfc_ecc_matrix - Defines ecc information storage format
> + * @pagesize:		Page size in bytes.
> + * @codeword_size:	Code word size information.
> + * @eccbits:		Number of ecc bits.
> + * @bch:		Bch / Hamming mode enable/disable.
> + * @eccsize:		Ecc size information.
> + */
> +struct anfc_ecc_matrix {
> +	u32 pagesize;
> +	u32 codeword_size;
> +	u8 eccbits;
> +	u8 bch;
> +	u16 eccsize;
> +};
> +
> +static const struct anfc_ecc_matrix ecc_matrix[] = {
> +	{512,	512,	1,	0,	0x3},
> +	{512,	512,	4,	1,	0x7},
> +	{512,	512,	8,	1,	0xD},
> +	/* 2K byte page */
> +	{2048,	512,	1,	0,	0xC},
> +	{2048,	512,	4,	1,	0x1A},
> +	{2048,	512,	8,	1,	0x34},
> +	{2048,	512,	12,	1,	0x4E},
> +	{2048,	1024,	24,	1,	0x54},
> +	/* 4K byte page */
> +	{4096,	512,	1,	0,	0x18},
> +	{4096,	512,	4,	1,	0x34},
> +	{4096,	512,	8,	1,	0x68},
> +	{4096,	512,	12,	1,	0x9C},
> +	{4096,	1024,	4,	1,	0xA8},
> +	/* 8K byte page */
> +	{8192,	512,	1,	0,	0x30},
> +	{8192,	512,	4,	1,	0x68},
> +	{8192,	512,	8,	1,	0xD0},
> +	{8192,	512,	12,	1,	0x138},
> +	{8192,	1024,	24,	1,	0x150},
> +	/* 16K byte page */
> +	{16384,	512,	1,	0,	0x60},
> +	{16384,	512,	4,	1,	0xD0},
> +	{16384,	512,	8,	1,	0x1A0},
> +	{16384,	512,	12,	1,	0x270},
> +	{16384,	1024,	24,	1,	0x2A0}
> +};
> +
> +/**
> + * struct anfc - Defines the Arasan NAND flash driver instance
> + * @chip:		NAND chip information structure.
> + * @mtd:		MTD information structure.
> + * @parts:		Pointer to the mtd_partition structure.
> + * @dev:		Pointer to the device structure.
> + * @base:		Virtual address of the NAND flash device.
> + * @curr_cmd:		Current command issued.
> + * @dma:		Dma enable/disable.
> + * @bch:		Bch / Hamming mode enable/disable.
> + * @err:		Error identifier.
> + * @iswriteoob:		Identifies if oob write operation is required.
> + * @buf:		Buffer used for read/write byte operations.
> + * @raddr_cycles:	Row address cycle information.
> + * @caddr_cycles:	Column address cycle information.
> + * @irq:		irq number
> + * @page:		Page address to be use for write oob operations.
> + * @pktsize:		Packet size for read / write operation.
> + * @bufshift:		Variable used for indexing buffer operation
> + * @rdintrmask:		Interrupt mask value for read operation.
> + * @bufrdy:		Completion event for buffer ready.
> + * @xfercomp:		Completion event for transfer complete.
> + * @ecclayout:		Ecc layout object
> + */
> +struct anfc {
> +	struct nand_chip chip;
> +	struct mtd_info mtd;
> +	struct mtd_partition *parts;

^^ This field is unused.

> +	struct device *dev;
> +
> +	void __iomem *base;
> +	int curr_cmd;
> +
> +	bool dma;
> +	bool bch;
> +	bool err;
> +	bool iswriteoob;
> +
> +	u8 buf[TEMP_BUF_SIZE];
> +
> +	u16 raddr_cycles;
> +	u16 caddr_cycles;
> +
> +	u32 irq;
> +	u32 page;
> +	u32 pktsize;
> +	u32 bufshift;
> +	u32 rdintrmask;
> +
> +	struct completion bufrdy;
> +	struct completion xfercomp;
> +	struct nand_ecclayout ecclayout;
> +};
> +
> +static u8 anfc_page(u32 pagesize)
> +{
> +	switch (pagesize) {
> +	case 512:
> +		return PAGE_SIZE_512;
> +	case 2048:
> +		return PAGE_SIZE_2K;
> +	case 4096:
> +		return PAGE_SIZE_4K;
> +	case 8192:
> +		return PAGE_SIZE_8K;
> +	case 16384:
> +		return PAGE_SIZE_16K;
> +	case 1024:
> +		return PAGE_SIZE_1K;
> +	default:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static inline void anfc_enable_intrs(struct anfc *nfc, u32 val)
> +{
> +	writel(val, nfc->base + INTR_STS_EN_OFST);
> +	writel(val, nfc->base + INTR_SIG_EN_OFST);
> +}
> +
> +static int anfc_wait_for_event(struct anfc *nfc, u32 event)
> +{
> +	struct completion *comp;
> +	int ret;
> +
> +	if (event == XFER_COMPLETE)
> +		comp = &nfc->xfercomp;
> +	else
> +		comp = &nfc->bufrdy;
> +
> +	ret = wait_for_completion_timeout(comp, msecs_to_jiffies(EVNT_TIMEOUT));
> +
> +	return ret;
> +}
> +
> +static inline void anfc_setpktszcnt(struct anfc *nfc, u32 pktsize,
> +				    u32 pktcount)
> +{
> +	writel(pktsize | (pktcount << PKT_CNT_SHIFT), nfc->base + PKT_OFST);
> +}
> +
> +static inline void anfc_set_eccsparecmd(struct anfc *nfc, u8 cmd1, u8 cmd2)
> +{
> +	writel(cmd1 | (cmd2 << CMD2_SHIFT) |
> +	       (nfc->caddr_cycles << ADDR_CYCLES_SHIFT),
> +	       nfc->base + ECC_SPR_CMD_OFST);
> +}
> +
> +static void anfc_setpagecoladdr(struct anfc *nfc, u32 page, u16 col)
> +{
> +	u32 val;
> +
> +	writel(col | (page << PG_ADDR_SHIFT), nfc->base + MEM_ADDR1_OFST);
> +
> +	val = readl(nfc->base + MEM_ADDR2_OFST);
> +	val = (val & ~MEM_ADDR_MASK) |
> +	      ((page >> PG_ADDR_SHIFT) & MEM_ADDR_MASK);
> +	writel(val, nfc->base + MEM_ADDR2_OFST);
> +}
> +
> +static void anfc_prepare_cmd(struct anfc *nfc, u8 cmd1, u8 cmd2,
> +			     u8 dmamode, u32 pagesize, u8 addrcycles)
> +{
> +	u32 regval;
> +
> +	regval = cmd1 | (cmd2 << CMD2_SHIFT);
> +	if (dmamode && nfc->dma)
> +		regval |= DMA_ENABLE << DMA_EN_SHIFT;
> +	if (addrcycles)
> +		regval |= addrcycles << ADDR_CYCLES_SHIFT;
> +	if (pagesize)
> +		regval |= anfc_page(pagesize) << PAGE_SIZE_SHIFT;
> +	writel(regval, nfc->base + CMD_OFST);
> +}
> +
> +static int anfc_device_ready(struct mtd_info *mtd,
> +			     struct nand_chip *chip)
> +{
> +	u8 status;
> +	u32 timeout = STATUS_TIMEOUT;
> +
> +	while (timeout--) {
> +		chip->cmdfunc(mtd, NAND_CMD_STATUS, 0, 0);
> +		status = chip->read_byte(mtd);
> +		if (status & ONFI_STATUS_READY) {
> +			if (status & ONFI_STATUS_FAIL)
> +				return NAND_STATUS_FAIL;
> +			return 0;
> +		}
> +	}

No, we can't just do a busy-wait loop at an arbitrary count of 2000
cycles. Can you do something that's interrupt-based? Or at least time
yourself with jiffies or something similar.

> +
> +	pr_err("%s timed out\n", __func__);
> +	return -ETIMEDOUT;
> +}
> +
> +static int anfc_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
> +			 int page)
> +{
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +
> +	chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
> +	if (nfc->dma)
> +		nfc->rdintrmask = XFER_COMPLETE;
> +	else
> +		nfc->rdintrmask = READ_READY;
> +	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
> +
> +	return 0;
> +}
> +
> +static int anfc_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
> +			  int page)
> +{
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +
> +	nfc->iswriteoob = true;
> +	chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, page);
> +	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
> +	nfc->iswriteoob = false;
> +
> +	return 0;
> +}
> +
> +static void anfc_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
> +{
> +	u32 i, pktcount, buf_rd_cnt = 0, pktsize;
> +	u32 *bufptr = (u32 *)buf;
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +	dma_addr_t paddr = 0;
> +
> +	if (nfc->curr_cmd == NAND_CMD_READ0) {
> +		pktsize = nfc->pktsize;
> +		if (mtd->writesize % pktsize)
> +			pktcount = mtd->writesize / pktsize + 1;
> +		else
> +			pktcount = mtd->writesize / pktsize;
> +	} else {
> +		pktsize = len;
> +		pktcount = 1;
> +	}
> +
> +	anfc_setpktszcnt(nfc, pktsize, pktcount);
> +
> +	if (nfc->dma) {
> +		paddr = dma_map_single(nfc->dev, buf, len, DMA_FROM_DEVICE);
> +		if (dma_mapping_error(nfc->dev, paddr)) {
> +			dev_err(nfc->dev, "Read buffer mapping error");
> +			return;
> +		}
> +		writel(paddr, nfc->base + DMA_ADDR0_OFST);
> +		writel(paddr >> 32, nfc->base + DMA_ADDR1_OFST);

drivers/mtd/nand/arasan_nfc.c: In function ‘anfc_read_buf’:
drivers/mtd/nand/arasan_nfc.c:355:3: warning: right shift count >= width of type [enabled by default]
   writel(paddr >> 32, nfc->base + DMA_ADDR1_OFST);
   ^

How about using upper_32_bits() and lower_32_bits()?

> +		anfc_enable_intrs(nfc, nfc->rdintrmask);
> +		writel(PROG_PGRD, nfc->base + PROG_OFST);
> +		anfc_wait_for_event(nfc, XFER_COMPLETE);
> +		dma_unmap_single(nfc->dev, paddr, len, DMA_FROM_DEVICE);
> +		return;
> +	}
> +
> +	anfc_enable_intrs(nfc, nfc->rdintrmask);
> +	writel(PROG_PGRD, nfc->base + PROG_OFST);
> +
> +	while (buf_rd_cnt < pktcount) {
> +
> +		anfc_wait_for_event(nfc, READ_READY);
> +		buf_rd_cnt++;
> +
> +		if (buf_rd_cnt == pktcount)
> +			anfc_enable_intrs(nfc, XFER_COMPLETE);
> +
> +		for (i = 0; i < pktsize / 4; i++)
> +			bufptr[i] = readl(nfc->base + DATA_PORT_OFST);
> +
> +		bufptr += (pktsize / 4);
> +
> +		if (buf_rd_cnt < pktcount)
> +			anfc_enable_intrs(nfc, nfc->rdintrmask);
> +	}
> +
> +	anfc_wait_for_event(nfc, XFER_COMPLETE);
> +}
> +
> +static void anfc_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
> +{
> +	u32 buf_wr_cnt = 0, pktcount = 1, i, pktsize;
> +	u32 *bufptr = (u32 *)buf;
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +	dma_addr_t paddr = 0;
> +
> +	if (nfc->iswriteoob) {
> +		pktsize = len;
> +		pktcount = 1;
> +	} else {
> +		pktsize = nfc->pktsize;
> +		pktcount = mtd->writesize / pktsize;
> +	}
> +
> +	anfc_setpktszcnt(nfc, pktsize, pktcount);
> +
> +	if (nfc->dma) {
> +		paddr = dma_map_single(nfc->dev, (void *)buf, len,
> +				       DMA_TO_DEVICE);
> +		if (dma_mapping_error(nfc->dev, paddr)) {
> +			dev_err(nfc->dev, "Write buffer mapping error");
> +			return;
> +		}
> +		writel(paddr, nfc->base + DMA_ADDR0_OFST);
> +		writel(paddr >> 32, nfc->base + DMA_ADDR1_OFST);

Same problem as in read_buf().

> +		anfc_enable_intrs(nfc, XFER_COMPLETE);
> +		writel(PROG_PGPROG, nfc->base + PROG_OFST);
> +		anfc_wait_for_event(nfc, XFER_COMPLETE);
> +		dma_unmap_single(nfc->dev, paddr, len, DMA_TO_DEVICE);
> +		return;
> +	}
> +
> +	anfc_enable_intrs(nfc, WRITE_READY);
> +	writel(PROG_PGPROG, nfc->base + PROG_OFST);
> +
> +	while (buf_wr_cnt < pktcount) {
> +		anfc_wait_for_event(nfc, WRITE_READY);
> +
> +		buf_wr_cnt++;
> +		if (buf_wr_cnt == pktcount)
> +			anfc_enable_intrs(nfc, XFER_COMPLETE);
> +
> +		for (i = 0; i < (pktsize / 4); i++)
> +			writel(bufptr[i], nfc->base + DATA_PORT_OFST);
> +
> +		bufptr += (pktsize / 4);
> +
> +		if (buf_wr_cnt < pktcount)
> +			anfc_enable_intrs(nfc, WRITE_READY);
> +	}
> +
> +	anfc_wait_for_event(nfc, XFER_COMPLETE);
> +}
> +
> +static int anfc_read_page_hwecc(struct mtd_info *mtd,
> +				struct nand_chip *chip, uint8_t *buf,
> +				int oob_required, int page)
> +{
> +	u32 val;
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +
> +	anfc_set_eccsparecmd(nfc, NAND_CMD_RNDOUT, NAND_CMD_RNDOUTSTART);
> +
> +	val = readl(nfc->base + CMD_OFST);
> +	val = val | ECC_ENABLE;
> +	writel(val, nfc->base + CMD_OFST);
> +
> +	if (nfc->dma)
> +		nfc->rdintrmask = XFER_COMPLETE;
> +	else
> +		nfc->rdintrmask = READ_READY;
> +
> +	if (!nfc->bch)
> +		nfc->rdintrmask = MBIT_ERROR;
> +
> +	chip->read_buf(mtd, buf, mtd->writesize);
> +
> +	val = readl(nfc->base + ECC_ERR_CNT_OFST);
> +	if (nfc->bch) {
> +		mtd->ecc_stats.corrected += val & PAGE_ERR_CNT_MASK;
> +	} else {
> +		val = readl(nfc->base + ECC_ERR_CNT_1BIT_OFST);
> +		mtd->ecc_stats.corrected += val;
> +		val = readl(nfc->base + ECC_ERR_CNT_2BIT_OFST);
> +		mtd->ecc_stats.failed += val;
> +		/* Clear ecc error count register 1Bit, 2Bit */
> +		writel(0x0, nfc->base + ECC_ERR_CNT_1BIT_OFST);
> +		writel(0x0, nfc->base + ECC_ERR_CNT_2BIT_OFST);
> +	}
> +	nfc->err = false;
> +
> +	if (oob_required)
> +		chip->ecc.read_oob(mtd, chip, page);
> +
> +	return 0;
> +}
> +
> +static int anfc_write_page_hwecc(struct mtd_info *mtd,
> +				 struct nand_chip *chip, const uint8_t *buf,
> +				 int oob_required)
> +{
> +	u32 val, i;
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +	uint8_t *ecc_calc = chip->buffers->ecccalc;
> +	uint32_t *eccpos = chip->ecc.layout->eccpos;
> +
> +	anfc_set_eccsparecmd(nfc, NAND_CMD_RNDIN, 0);
> +
> +	val = readl(nfc->base + CMD_OFST);
> +	val = val | ECC_ENABLE;
> +	writel(val, nfc->base + CMD_OFST);
> +
> +	chip->write_buf(mtd, buf, mtd->writesize);
> +
> +	if (oob_required) {
> +		anfc_device_ready(mtd, chip);
> +		chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, nfc->page);
> +		if (nfc->dma)
> +			nfc->rdintrmask = XFER_COMPLETE;
> +		else
> +			nfc->rdintrmask = READ_READY;
> +		chip->read_buf(mtd, ecc_calc, mtd->oobsize);
> +		for (i = 0; i < chip->ecc.total; i++)
> +			chip->oob_poi[eccpos[i]] = ecc_calc[eccpos[i]];
> +		chip->ecc.write_oob(mtd, chip, nfc->page);
> +	}
> +
> +	return 0;
> +}
> +
> +static u8 anfc_read_byte(struct mtd_info *mtd)
> +{
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +
> +	return nfc->buf[nfc->bufshift++];
> +}
> +
> +static void anfc_readfifo(struct anfc *nfc, u32 prog, u32 size)
> +{
> +	u32 i, *bufptr = (u32 *)&nfc->buf[0];
> +
> +	anfc_enable_intrs(nfc, READ_READY);
> +
> +	writel(prog, nfc->base + PROG_OFST);
> +	anfc_wait_for_event(nfc, READ_READY);
> +
> +	anfc_enable_intrs(nfc, XFER_COMPLETE);
> +
> +	for (i = 0; i < size / 4; i++)
> +		bufptr[i] = readl(nfc->base + DATA_PORT_OFST);
> +
> +	anfc_wait_for_event(nfc, XFER_COMPLETE);
> +}
> +
> +static int anfc_ecc_init(struct mtd_info *mtd,
> +			 struct nand_ecc_ctrl *ecc)
> +{
> +	u32 oob_index, i, ecc_addr, regval, bchmode = 0;
> +	struct nand_chip *nand_chip = mtd->priv;
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +	int found = -1;
> +
> +	nand_chip->ecc.mode = NAND_ECC_HW;
> +	nand_chip->ecc.read_page = anfc_read_page_hwecc;
> +	nand_chip->ecc.write_page = anfc_write_page_hwecc;
> +	nand_chip->ecc.write_oob = anfc_write_oob;
> +	nand_chip->ecc.read_oob = anfc_read_oob;
> +
> +	for (i = 0; i < sizeof(ecc_matrix) / sizeof(struct anfc_ecc_matrix);
> +	     i++) {
> +		if ((ecc_matrix[i].pagesize == mtd->writesize) &&
> +		    (ecc_matrix[i].codeword_size >= nand_chip->ecc_step_ds)) {
> +			if (ecc_matrix[i].eccbits >=
> +			    nand_chip->ecc_strength_ds) {
> +				found = i;
> +				break;
> +			}
> +			found = i;
> +		}
> +	}
> +
> +	if (found < 0) {
> +		dev_err(nfc->dev, "ECC scheme not supported");
> +		return 1;
> +	}
> +	if (ecc_matrix[found].bch) {
> +		switch (ecc_matrix[found].eccbits) {
> +		case 12:
> +			bchmode = 0x1;
> +			break;
> +		case 8:
> +			bchmode = 0x2;
> +			break;
> +		case 4:
> +			bchmode = 0x3;
> +			break;
> +		case 24:
> +			bchmode = 0x4;
> +			break;
> +		default:
> +			bchmode = 0x0;
> +		}
> +	}
> +
> +	nand_chip->ecc.strength = ecc_matrix[found].eccbits;
> +	nand_chip->ecc.size = ecc_matrix[found].codeword_size;
> +	nand_chip->ecc.steps = ecc_matrix[found].pagesize /
> +			       ecc_matrix[found].codeword_size;
> +	nand_chip->ecc.bytes = ecc_matrix[found].eccsize /
> +			       nand_chip->ecc.steps;
> +	nfc->ecclayout.eccbytes = ecc_matrix[found].eccsize;
> +	nfc->bch = ecc_matrix[found].bch;
> +	oob_index = nand_chip->onfi_params.spare_bytes_per_page -
> +		    nfc->ecclayout.eccbytes;

sparse doesn't like this:

drivers/mtd/nand/arasan_nfc.c:599:43: warning: restricted __le16 degrades to integer [sparse]

You need to use __le16_to_cpu() when accessing ONFI params. But really,
you should be using mtd->oobsize, not onfi_params.

> +	ecc_addr = mtd->writesize + oob_index;
> +
> +	for (i = 0; i < nand_chip->ecc.size; i++)
> +		nfc->ecclayout.eccpos[i] = oob_index + i;
> +
> +	nfc->ecclayout.oobfree->offset = 2;
> +	nfc->ecclayout.oobfree->length = oob_index -
> +					 nfc->ecclayout.oobfree->offset;
> +
> +	nand_chip->ecc.layout = &(nfc->ecclayout);
> +	regval = ecc_addr | (ecc_matrix[found].eccsize << ECC_SIZE_SHIFT) |
> +		 (ecc_matrix[found].bch << BCH_EN_SHIFT);
> +	writel(regval, nfc->base + ECC_OFST);
> +
> +	regval = readl(nfc->base + MEM_ADDR2_OFST);
> +	regval = (regval & ~(BCH_MODE_MASK)) | (bchmode << BCH_MODE_SHIFT);
> +	writel(regval, nfc->base + MEM_ADDR2_OFST);
> +
> +	if (nand_chip->ecc_step_ds >= 1024)
> +		nfc->pktsize = 1024;
> +	else
> +		nfc->pktsize = 512;
> +
> +	return 0;
> +}
> +
> +static void anfc_cmd_function(struct mtd_info *mtd,
> +			      unsigned int cmd, int column, int page_addr)
> +{
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +	bool wait = false, read = false;
> +	u32 addrcycles, prog;
> +	u32 *bufptr = (u32 *)&nfc->buf[0];
> +
> +	nfc->bufshift = 0;
> +	nfc->curr_cmd = cmd;
> +
> +	if (page_addr == -1)
> +		page_addr = 0;
> +	if (column == -1)
> +		column = 0;
> +
> +	switch (cmd) {
> +	case NAND_CMD_RESET:
> +		anfc_prepare_cmd(nfc, cmd, 0, 0, 0, 0);
> +		prog = PROG_RST;
> +		wait = true;
> +		break;
> +	case NAND_CMD_SEQIN:
> +		addrcycles = nfc->raddr_cycles + nfc->caddr_cycles;
> +		nfc->page = page_addr;
> +		anfc_prepare_cmd(nfc, cmd, NAND_CMD_PAGEPROG, 1,
> +				 mtd->writesize, addrcycles);
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		break;
> +	case NAND_CMD_READOOB:
> +		column += mtd->writesize;
> +	case NAND_CMD_READ0:
> +	case NAND_CMD_READ1:
> +		addrcycles = nfc->raddr_cycles + nfc->caddr_cycles;
> +		anfc_prepare_cmd(nfc, NAND_CMD_READ0, NAND_CMD_READSTART, 1,
> +				 mtd->writesize, addrcycles);
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		break;
> +	case NAND_CMD_RNDOUT:
> +		anfc_prepare_cmd(nfc, cmd, NAND_CMD_RNDOUTSTART, 1,
> +				 mtd->writesize, 2);
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		if (nfc->dma)
> +			nfc->rdintrmask = XFER_COMPLETE;
> +		else
> +			nfc->rdintrmask = READ_READY;
> +		break;
> +	case NAND_CMD_PARAM:
> +		anfc_prepare_cmd(nfc, cmd, 0, 0, 0, 1);
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		anfc_setpktszcnt(nfc, sizeof(struct nand_onfi_params), 1);
> +		anfc_readfifo(nfc, PROG_RDPARAM,
> +				sizeof(struct nand_onfi_params));
> +		break;
> +	case NAND_CMD_READID:
> +		anfc_prepare_cmd(nfc, cmd, 0, 0, 0, 1);
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		anfc_setpktszcnt(nfc, ONFI_ID_LEN, 1);
> +		anfc_readfifo(nfc, PROG_RDID, ONFI_ID_LEN);
> +		break;
> +	case NAND_CMD_ERASE1:
> +		addrcycles = nfc->raddr_cycles;
> +		prog = PROG_ERASE;
> +		anfc_prepare_cmd(nfc, cmd, NAND_CMD_ERASE2, 0, 0, addrcycles);
> +		column = page_addr & 0xffff;
> +		page_addr = (page_addr >> PG_ADDR_SHIFT) & 0xffff;
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		wait = true;
> +		break;
> +	case NAND_CMD_STATUS:
> +		anfc_prepare_cmd(nfc, cmd, 0, 0, 0, 0);
> +		anfc_setpktszcnt(nfc, 1, 1);
> +		anfc_setpagecoladdr(nfc, page_addr, column);
> +		prog = PROG_STATUS;
> +		wait = read = true;
> +		break;
> +	default:
> +		return;
> +	}
> +
> +	if (wait) {
> +		anfc_enable_intrs(nfc, XFER_COMPLETE);
> +		writel(prog, nfc->base + PROG_OFST);
> +		anfc_wait_for_event(nfc, XFER_COMPLETE);
> +	}
> +
> +	if (read)
> +		bufptr[0] = readl(nfc->base + FLASH_STS_OFST);
> +}
> +
> +static void anfc_select_chip(struct mtd_info *mtd, int num)
> +{
> +	u32 val;
> +	struct anfc *nfc = container_of(mtd, struct anfc, mtd);
> +
> +	if (num == -1)
> +		return;
> +
> +	val = readl(nfc->base + MEM_ADDR2_OFST);
> +	val = (val & ~(CS_MASK)) | (num << CS_SHIFT);
> +	writel(val, nfc->base + MEM_ADDR2_OFST);
> +}
> +
> +static irqreturn_t anfc_irq_handler(int irq, void *ptr)
> +{
> +	struct anfc *nfc = ptr;
> +	u32 regval = 0, status;
> +
> +	status = readl(nfc->base + INTR_STS_OFST);
> +	if (status & XFER_COMPLETE) {
> +		complete(&nfc->xfercomp);
> +		regval |= XFER_COMPLETE;
> +	}
> +
> +	if (status & READ_READY) {
> +		complete(&nfc->bufrdy);
> +		regval |= READ_READY;
> +	}
> +
> +	if (status & WRITE_READY) {
> +		complete(&nfc->bufrdy);
> +		regval |= WRITE_READY;
> +	}
> +
> +	if (status & MBIT_ERROR) {
> +		nfc->err = true;
> +		complete(&nfc->bufrdy);
> +		regval |= MBIT_ERROR;
> +	}
> +
> +	if (regval) {
> +		writel(regval, nfc->base + INTR_STS_OFST);
> +		writel(0, nfc->base + INTR_STS_EN_OFST);
> +		writel(0, nfc->base + INTR_SIG_EN_OFST);
> +
> +		return IRQ_HANDLED;
> +	}
> +
> +	return IRQ_NONE;
> +}
> +
> +static int anfc_probe(struct platform_device *pdev)
> +{
> +	struct anfc *nfc;
> +	struct mtd_info *mtd;
> +	struct nand_chip *nand_chip;
> +	struct resource *res;
> +	struct mtd_part_parser_data ppdata;
> +	int err;
> +
> +	nfc = devm_kzalloc(&pdev->dev, sizeof(*nfc), GFP_KERNEL);
> +	if (!nfc)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	nfc->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(nfc->base))
> +		return PTR_ERR(nfc->base);
> +
> +	mtd = &nfc->mtd;
> +	nand_chip = &nfc->chip;
> +	nand_chip->priv = nfc;
> +	mtd->priv = nand_chip;
> +	mtd->owner = THIS_MODULE;
> +	mtd->name = DRIVER_NAME;
> +	nfc->dev = &pdev->dev;

You should set mtd->dev.parent too.

> +
> +	nand_chip->cmdfunc = anfc_cmd_function;
> +	nand_chip->waitfunc = anfc_device_ready;
> +	nand_chip->chip_delay = 30;
> +	nand_chip->read_buf = anfc_read_buf;
> +	nand_chip->write_buf = anfc_write_buf;
> +	nand_chip->read_byte = anfc_read_byte;
> +	nand_chip->bbt_options = NAND_BBT_USE_FLASH;
> +	nand_chip->select_chip = anfc_select_chip;
> +	mtd->size = nand_chip->chipsize;

This line looks superfluous. chipsize isn't even set at this point.

> +	nfc->dma = of_property_read_bool(pdev->dev.of_node,
> +					 "arasan,has-mdma");
> +	platform_set_drvdata(pdev, nfc);
> +	init_completion(&nfc->bufrdy);
> +	init_completion(&nfc->xfercomp);
> +	nfc->irq = platform_get_irq(pdev, 0);

Check for errors?

> +	err = devm_request_irq(&pdev->dev, nfc->irq, anfc_irq_handler,
> +			       0, "arasannfc", nfc);
> +	if (err)
> +		return err;
> +
> +	if (nand_scan_ident(mtd, 1, NULL)) {
> +		dev_err(&pdev->dev, "nand_scan_ident for NAND failed\n");
> +		return -ENXIO;
> +	}
> +	nfc->raddr_cycles = nand_chip->onfi_params.addr_cycles & 0xF;
> +	nfc->caddr_cycles = (nand_chip->onfi_params.addr_cycles >> 4) & 0xF;

Do you *have* to get this from ONFI? What if someone uses non-ONFI
flash? You should at least check if this is an ONFI flash before using
these param values.

> +
> +	if (anfc_ecc_init(mtd, &nand_chip->ecc))
> +		return -ENXIO;
> +
> +	if (nand_scan_tail(mtd)) {
> +		dev_err(&pdev->dev, "nand_scan_tail for NAND failed\n");
> +		return -ENXIO;
> +	}
> +
> +	ppdata.of_node = pdev->dev.of_node;
> +
> +	mtd_device_parse_register(&nfc->mtd, NULL, &ppdata, NULL, 0);
> +	return 0;

You're ignoring the return value from mtd_device_parse_register(). How
about:

	return mtd_device_parse_register(&nfc->mtd, NULL, &ppdata, NULL, 0);

> +}
> +
> +static int anfc_remove(struct platform_device *pdev)
> +{
> +	struct anfc *nfc = platform_get_drvdata(pdev);
> +
> +	nand_release(&nfc->mtd);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id anfc_ids[] = {
> +	{ .compatible = "arasan,nfc-v3p10" },
> +	{  }
> +};
> +MODULE_DEVICE_TABLE(of, anfc_ids);
> +
> +static struct platform_driver anfc_driver = {
> +	.driver = {
> +		.name = DRIVER_NAME,
> +		.of_match_table = anfc_ids,
> +	},
> +	.probe = anfc_probe,
> +	.remove = anfc_remove,
> +};
> +module_platform_driver(anfc_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Xilinx, Inc");
> +MODULE_DESCRIPTION("Arasan NAND Flash Controller Driver");

Brian
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