[PATCH 2/2] mtd: rawnand: meson: add support for Amlogic NAND flash controller

Yixun Lan yixun.lan at amlogic.com
Wed Jul 18 02:38:56 PDT 2018


Hi Roris

thanks for all your suggestions!

It actually takes us some time to digest all your comments ;-)
and get back to you on these questions.


On 06/25/18 03:38, Boris Brezillon wrote:
> 
> 
> Hi Yixun,
> 
> On Wed, 13 Jun 2018 16:13:14 +0000
> Yixun Lan <yixun.lan at amlogic.com> wrote:
> 
>> From: Liang Yang <liang.yang at amlogic.com>
>>
>> Add initial support for the Amlogic NAND flash controller which found
>> in the Meson-GXBB/GXL/AXG SoCs.
>>
>> Singed-off-by: Liang Yang <liang.yang at amlogic.com>
>> Signed-off-by: Yixun Lan <yixun.lan at amlogic.com>
>> ---
>>  drivers/mtd/nand/raw/Kconfig      |    8 +
>>  drivers/mtd/nand/raw/Makefile     |    3 +
>>  drivers/mtd/nand/raw/meson_nand.c | 1422 +++++++++++++++++++++++++++++
>>  3 files changed, 1433 insertions(+)
>>  create mode 100644 drivers/mtd/nand/raw/meson_nand.c
> 
> Can you run checkpatch.pl --strict and fix the coding style issues?
> 
sure, we will be more cautious about this

>>
>> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
>> index 19a2b283fbbe..b3c17a3ca8f4 100644
>> --- a/drivers/mtd/nand/raw/Kconfig
>> +++ b/drivers/mtd/nand/raw/Kconfig
>> @@ -534,4 +534,12 @@ config MTD_NAND_MTK
>>  	  Enables support for NAND controller on MTK SoCs.
>>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>>  
>> +config MTD_NAND_MESON
>> +	tristate "Support for NAND flash controller on Amlogic's Meson SoCs"
>> +	depends on ARCH_MESON || COMPILE_TEST
>> +	select COMMON_CLK_REGMAP_MESON
>> +	select MFD_SYSCON
>> +	help
>> +	  Enables support for NAND controller on Amlogic's Meson SoCs.
>> +
>>  endif # MTD_NAND
>> diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
>> index 165b7ef9e9a1..cdf6162f38c3 100644
>> --- a/drivers/mtd/nand/raw/Makefile
>> +++ b/drivers/mtd/nand/raw/Makefile
>> @@ -1,5 +1,7 @@
>>  # SPDX-License-Identifier: GPL-2.0
>>  
>> +ccflags-$(CONFIG_MTD_NAND_MESON) += -I$(srctree)/drivers/clk/meson
> 
> Please don't do that. If you need to expose common regs, put them
> in include/linux/soc/meson/. I'm also not sure why you need to access
> the clk regs directly. Why can't you expose the MMC/NAND clk as a clk
> provider whose driver would be placed in drivers/clk and which would use
> the mmc syscon. This way the same clk driver could be used for both
> MMC and NAND clk indifferently, and the NAND driver would be much
> simpler.
> 

this is already addressed in another thread, as we will model it as a
standard clock driver.

so this cflags can be dropped.

>> +
>>  obj-$(CONFIG_MTD_NAND)			+= nand.o
>>  obj-$(CONFIG_MTD_NAND_ECC)		+= nand_ecc.o
>>  obj-$(CONFIG_MTD_NAND_BCH)		+= nand_bch.o
>> @@ -56,6 +58,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        += hisi504_nand.o
>>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
>>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
>>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
>> +obj-$(CONFIG_MTD_NAND_MESON)		+= meson_nand.o
>>  
>>  nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
>>  nand-objs += nand_amd.o
>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>> new file mode 100644
>> index 000000000000..28abc3684772
>> --- /dev/null
>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>> @@ -0,0 +1,1422 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +/*
>> + * Amlogic Meson Nand Flash Controller Driver
>> + *
>> + * Copyright (c) 2018 Amlogic, inc.
>> + * Author: Liang Yang <liang.yang at amlogic.com>
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/clk.h>
>> +#include <linux/mtd/rawnand.h>
>> +#include <linux/mtd/mtd.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/regmap.h>
>> +#include <linux/module.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include "clk-regmap.h"
>> +
>> +#define NFC_REG_CMD		0x00
>> +#define NFC_REG_CFG		0x04
>> +#define NFC_REG_DADR		0x08
>> +#define NFC_REG_IADR		0x0c
>> +#define NFC_REG_BUF		0x10
>> +#define NFC_REG_INFO		0x14
>> +#define NFC_REG_DC		0x18
>> +#define NFC_REG_ADR		0x1c
>> +#define NFC_REG_DL		0x20
>> +#define NFC_REG_DH		0x24
>> +#define NFC_REG_CADR		0x28
>> +#define NFC_REG_SADR		0x2c
>> +#define NFC_REG_PINS		0x30
>> +#define NFC_REG_VER		0x38
>> +
> 
> Can you put the reg offsets next to their field definitions?
> 
actually, we would prefer to put all the CMD definition below the reg
offset, so it will better reflect what's it belong to.


>> +
>> +#define NFC_CMD_DRD		(0x8 << 14)
>> +#define NFC_CMD_IDLE		(0xc << 14)
>> +#define NFC_CMD_DWR		(0x4 << 14)
>> +#define NFC_CMD_CLE		(0x5 << 14)
>> +#define NFC_CMD_ALE		(0x6 << 14)
>> +#define NFC_CMD_ADL		((0 << 16) | (3 << 20))
>> +#define NFC_CMD_ADH		((1 << 16) | (3 << 20))
>> +#define NFC_CMD_AIL		((2 << 16) | (3 << 20))
>> +#define NFC_CMD_AIH		((3 << 16) | (3 << 20))
>> +#define NFC_CMD_SEED		((8 << 16) | (3 << 20))
>> +#define NFC_CMD_M2N		((0 << 17) | (2 << 20))
>> +#define NFC_CMD_N2M		((1 << 17) | (2 << 20))
>> +#define NFC_CMD_RB		(1 << 20)
>> +#define NFC_CMD_IO6		((0xb << 10) | (1 << 18))
>> +
>> +#define NFC_RB_USED		(1 << 23)
>> +#define NFC_LARGE_PAGE		(1 << 22)
>> +#define NFC_RW_OPS		(2 << 20)
>> +
>> +#define NAND_TWB_TIME_CYCLE	10
>> +
>> +#define CMDRWGEN(cmd_dir, ran, bch, short_mode, page_size, pages)	\
>> +	(								\
>> +		(cmd_dir)			|			\
>> +		((ran) << 19)			|			\
>> +		((bch) << 14)			| 			\
>> +		((short_mode) << 13)		|			\
>> +		(((page_size) & 0x7f) << 6)	|			\
>> +		((pages) & 0x3f)					\
>> +	)
>> +
>> +#define GENCMDDADDRL(adl, addr)		((adl) | ((addr) & 0xffff))
>> +#define GENCMDDADDRH(adh, addr)		((adh) | (((addr) >> 16) & 0xffff))
>> +#define GENCMDIADDRL(ail, addr)		((ail) | ((addr) & 0xffff))
>> +#define GENCMDIADDRH(aih, addr)		((aih) | (((addr) >> 16) & 0xffff))
>> +
>> +#define RB_STA(x)		(1 << (26 + x))
>> +
>> +#define ECC_CHECK_RETURN_FF	(-1)
>> +
>> +#define NAND_CE0		(0xe << 10)
>> +#define NAND_CE1		(0xd << 10)
>> +
>> +#define DMA_BUSY_TIMEOUT	0x100000
>> +
>> +#define MAX_CE_NUM		2
>> +#define RAN_ENABLE		1
>> +
>> +#define SD_EMMC_CLOCK 		0x00
>> +#define CLK_ALWAYS_ON		BIT(28)
>> +#define CLK_SELECT_NAND		BIT(31)
>> +#define CLK_DIV_MASK		GENMASK(5, 0)
>> +#define CLK_SRC_MASK		GENMASK(7, 6)
>> +
>> +#define NFC_CLK_CYCLE		6
>> +
>> +/* nand flash controller delay 3 ns */
>> +#define NFC_DEFAULT_DELAY 3000
>> +
>> +#define MAX_ECC_INDEX	10
>> +
>> +#define MUX_CLK_NUM_PARENTS 2
>> +
>> +struct meson_nfc_info_format {
>> +	u16 info_bytes;
>> +	u8 zero_cnt; /* bit0~5 is valid */
>> +	struct ecc_sta {
>> +		u8 eccerr_cnt : 6;
>> +		u8 notused : 1;
>> +		u8 completed : 1;
>> +	} ecc;
>> +	u32 reserved;
>> +};
>> +
>> +#define	PER_INFO_BYTE	(sizeof(struct meson_nfc_info_format))
>> +
>> +struct meson_nfc_nand_chip {
>> +	struct list_head node;
>> +	struct nand_chip nand;
>> +	/*
>> +	 * Then NAND controller support two oob modes:
>> +	 *  a) 2 user bytes with each ecc page;
>> +	 *  b) 16 user bytes with 1st ecc page and zero user byte
>> +	 *      with the other ecc pages.
>> +	 * when using as mtd mode, the driver prefer to use 2 user bytes mode.
> 
> Why not using this mode unconditionally? What's the point of
> maintaining 2 different page layout if only one is used?
> 

after consideration, we will just stick to mode a)

>> +	 */
>> +	int user_mode;
>> +	int rand_mode; /* 0: disable scramble, 1: enable scramble */
>> +	int bch_mode;
>> +	int cs;
>> +
>> +	u8 *data_buf;
>> +	u8 *info_buf;
>> +};
>> +
>> +/*
>> + * While booting from NAND, a page0 data is needed to tell ROM boot code
>> + * to read SPL image, and the ROM boot code need to know which ecc mode
>> + * is selected and whether scramble is enabled or not, and so on.
>> + *
>> + * So when updating SPL image, the driver need to store these informations
>> + * into the page0, and SPL image will be loadded into next page - the page1.
> 
> Clearly not the kind of information that belongs in the NAND controller
> driver. We had the same problem on sunxi platforms where the first few
> blocks are written with a different ECC/scrambler setup (the
> ROM code only supports a pre-defined set of ECC/scrambler configs that
> it tries until it finds one that works).
> 
> What we did to solve that is write the SPL partition in raw mode (ECC
> and scrambler disabled) with an image that already contains the ECC
> bytes has the data appropriately scrambled (for the record, we use the
> sunxi-spl-image-builder [1] tool to generate this raw image).
> 

will drop this as we also have tools ready to generate the raw image.
thanks for suggesting.

>> + */
>> +struct meson_nand_setup {
>> +	u32 d32;
>> +	u16 id;
>> +	u16 max;
>> +};
>> +
>> +struct meson_nand_page0 {
>> +	struct meson_nand_setup nand_setup;
>> +	unsigned char page_list[16];
>> +	unsigned short reserved[32];
>> +};
>> +
>> +struct meson_nand_ecc {
>> +	int bch;
>> +	int strength;
>> +	int parity;
>> +};
>> +
>> +struct meson_nfc_data {
>> +	struct meson_nand_ecc *ecc;
>> +	int ecc_num;
>> +	int bch_mode;
>> +	int short_bch;
>> +};
>> +
>> +struct meson_nfc_param {
>> +	int chip_select;
>> +	int rb_select;
>> +
>> +	int page_size;
>> +	int oob_size;
>> +	int ecc_size;
>> +	int ecc_bytes;
>> +
>> +	int rand_mode;
>> +	int oob_mode;
>> +	int bch_mode;
>> +	int ecc_step;
>> +
>> +	int ecc_max;
>> +};
> 
> Looks like most of these information are tied to the NAND chip and not
> the NAND controller. They should probably be moved to
> meson_nfc_nand_chip.
> 
sure, we fix it

>> +
>> +struct meson_nfc {
>> +	struct nand_hw_control controller;
>> +	struct clk *core_clk;
>> +	struct clk *device_clk;
>> +
>> +	struct device *dev;
>> +	void __iomem *reg_base;
>> +	struct regmap *reg_clk;
>> +
>> +	struct completion completion;
>> +	struct list_head chips;
>> +	struct meson_nfc_data *data;
>> +	struct meson_nfc_param param;
>> +	struct meson_nand_page0 *page0;
>> +
>> +	u8 *data_buf;
>> +	u8 *info_buf;
>> +};
>> +
>> +enum {
>> +	NFC_ECC_NONE	= 0,
>> +	NFC_ECC_BCH8,		/* bch8 with ecc page size of 512B */
>> +	NFC_ECC_BCH8_1K,	/* bch8 with ecc page size of 1024B */
>> +	NFC_ECC_BCH24_1K,
>> +	NFC_ECC_BCH30_1K,
>> +	NFC_ECC_BCH40_1K,
>> +	NFC_ECC_BCH50_1K,
>> +	NFC_ECC_BCH60_1K,
>> +
>> +	/*
>> +	 * Short mode is special only for page 0 when inplement booting
>> +	 * from nand, which means a small size(384 bit / 8 = 48 Byte) of
>> +	 * ecc page is used with a fixed ecc mode. rom code will use short mode
>> +	 * to read page0 for getting nand parameters such as ecc, scramber, etc.
>> +	 *
>> +	 * Example, in GXL SoC, the first page adopt the short mode with
>> +	 * 60bit ecc, while in AXG SoC, it adopt short mode with 8bit ecc.
>> +	 */
>> +	NFC_ECC_BCH_SHORT,
> 
> Let's see if we can avoid supporting this mode. I'm pretty sure you
> have all the information you need to generate ECC bytes and scramble
> data in SW. Then, all you'll need from the NAND controller driver is a
> way to write thing in raw mode, which I'll ask you to support
> anyway ;-).
> 

sure, as mentioned above, we have all the information known and tools to
generate image which can be written in raw mode.

>> +};
>> +
>> +enum {
>> +	NFC_USER2_OOB_BYTES		= 2,
>> +	NFC_USER16_OOB_BYTES		= 16,
>> +};
>> +
>> +#define MESON_ECC_DATA(b, s, p)				\
>> +	{ .bch = (b),	.strength = (s),	.parity = (p) }
>> +
>> +struct meson_nand_ecc meson_gxl_ecc[] = {
>> +	MESON_ECC_DATA(NFC_ECC_NONE, 0, 0),
>> +	MESON_ECC_DATA(NFC_ECC_BCH8, 8, 14),
>> +	MESON_ECC_DATA(NFC_ECC_BCH8_1K, 8, 14),
>> +	MESON_ECC_DATA(NFC_ECC_BCH24_1K, 24, 42),
>> +	MESON_ECC_DATA(NFC_ECC_BCH30_1K, 30, 54),
>> +	MESON_ECC_DATA(NFC_ECC_BCH40_1K, 40, 70),
>> +	MESON_ECC_DATA(NFC_ECC_BCH50_1K, 50, 88),
>> +	MESON_ECC_DATA(NFC_ECC_BCH60_1K, 60, 106),
>> +	MESON_ECC_DATA(NFC_ECC_BCH_SHORT, 0xff, 0xff),
>> +};
>> +
>> +struct meson_nand_ecc meson_axg_ecc[] = {
>> +	MESON_ECC_DATA(NFC_ECC_NONE, 0, 0),
>> +	MESON_ECC_DATA(NFC_ECC_BCH8, 8, 14),
>> +	MESON_ECC_DATA(NFC_ECC_BCH8_1K, 8, 14),
>> +	MESON_ECC_DATA(NFC_ECC_BCH_SHORT, 0xff, 0xff),
>> +};
>> +
>> +static inline struct meson_nfc_nand_chip *to_meson_nand(struct nand_chip *nand)
>> +{
>> +	return container_of(nand, struct meson_nfc_nand_chip, nand);
>> +}
>> +
>> +static int meson_nfc_page0_gen(struct meson_nfc *nfc)
>> +{
>> +	u32 cmd;
>> +
>> +	nfc->page0 = devm_kzalloc(nfc->dev,
>> +		sizeof(struct meson_nand_page0), GFP_KERNEL);
>> +	if(!nfc->page0)
>> +		return -ENOMEM;
>> +
>> +	cmd = CMDRWGEN(NFC_CMD_N2M, nfc->param.rand_mode,
>> +		nfc->param.bch_mode, 0,
>> +		nfc->param.ecc_size >> 3,
>> +		nfc->param.ecc_step);
>> +	cmd |= NFC_RB_USED | NFC_LARGE_PAGE | NFC_RW_OPS;
>> +	nfc->page0->nand_setup.d32 = cmd;
>> +
>> +	return 0;
>> +}
>> +
>> +static void meson_nfc_select_chip(struct mtd_info *mtd, int chip)
>> +{
>> +	struct nand_chip *nand = mtd_to_nand(mtd);
>> +	struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>> +	struct meson_nfc *nfc = nand_get_controller_data(nand);
>> +
>> +	if (chip != meson_chip->cs)
> 
> I know it's not clear at all, but chip is not encoding the NAND
> controller CS id, but the NAND chip CS id, which can be != 0 for
> multi-die chips.
> 
> To extract the NAND controller CS id, you'll have to parse the NAND
> chip node reg prop, and store the information somewhere in
> meson_nfc_nand_chip. Go check the sunxi if you want an example.
> 
ok, we will fix this

>> +		return;
>> +
>> +	nfc->param.chip_select = chip ? NAND_CE1 : NAND_CE0;
>> +	nfc->param.rb_select = chip ? NAND_CE1 : NAND_CE0;
>> +	nfc->param.oob_mode =
>> +		(meson_chip->user_mode == NFC_USER2_OOB_BYTES) ? 0 : 1;
>> +	nfc->param.rand_mode = meson_chip->rand_mode;
>> +	nfc->param.bch_mode = meson_chip->bch_mode;
>> +
>> +	nfc->param.ecc_step = mtd->writesize / nand->ecc.size;
>> +	nfc->param.ecc_size = nand->ecc.size;
>> +	nfc->param.ecc_bytes =  nand->ecc.bytes;
>> +	nfc->param.page_size = mtd->writesize;
>> +	nfc->param.oob_size =  mtd->oobsize;
>> +	nfc->param.ecc_max = nand->ecc.strength;
>> +
>> +	nfc->data_buf = meson_chip->data_buf;
>> +	nfc->info_buf = meson_chip->info_buf;
>> +}
>> +
>> +static inline void meson_nfc_cmd_idle(struct meson_nfc *nfc, u32 time)
>> +{
>> +	writel(nfc->param.chip_select | NFC_CMD_IDLE | (time & 0x3ff),
>> +			nfc->reg_base + NFC_REG_CMD);
>> +}
>> +
>> +static void meson_nfc_cmd_ctrl(struct mtd_info *mtd,
>> +					int cmd, unsigned int ctrl)
> 
> ->cmd_ctrl() has recently been deprecated in favor of ->exec_op(). You
> can have a look at the marvell, v610 or fsmc drivers if you want to
> have an idea of how ->exec_op() should be implemented. Miquel and I are
> also here to help if you have any questions.
> 

follow your suggestion, we have implemented the exec_op() interface,
we'd really appreciate if you can help to review this ..

>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
>> +
>> +	if (cmd == NAND_CMD_NONE)
>> +		return;
>> +
>> +	cmd = nfc->param.chip_select | (cmd & 0xff);
>> +	cmd |= (ctrl & NAND_CLE) ? NFC_CMD_CLE : NFC_CMD_ALE;
>> +
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +}
>> +
>> +static inline void meson_nfc_cmd_seed(struct meson_nfc *nfc, u32 seed)
>> +{
>> +	writel(NFC_CMD_SEED | (0xc2 + (seed & 0x7fff)),
>> +			nfc->reg_base + NFC_REG_CMD);
>> +}
>> +
>> +static void meson_nfc_cmd_m2n(struct meson_nfc *nfc, int raw)
> 
> n2m -> nand2mem ?
> 
yes, it is

>> +{
>> +	u32 cmd, pagesize, pages, shortm = 0;
>> +	int bch = nfc->param.bch_mode;
>> +	int len = nfc->param.page_size;
>> +
>> +	pagesize = nfc->param.ecc_size;
>> +
>> +	if (unlikely(raw)) {
> 
> I think you'll have plenty of things to optimize before this branch
> prediction becomes the bottleneck ;-). Please don't use
> unlikely()/likely() statements unless you have numbers showing a
> noticeable improvement.
> 
thank you for the advice, it's not really necessary, will drop them


>> +		bch = NAND_ECC_NONE;
>> +		len = nfc->param.page_size + nfc->param.oob_size;
>> +		cmd = NFC_CMD_M2N |
>> +			(len & 0x3fff) | (nfc->param.rand_mode << 19);
>> +		writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +		return;
>> +	}
>> +
>> +	if (unlikely(bch == NFC_ECC_BCH_SHORT)) {
>> +		bch = nfc->data->short_bch;
>> +		pagesize = 384 >> 3;
>> +		pages = len / nfc->param.ecc_size;
>> +		memcpy(nfc->data_buf,
>> +			nfc->page0, sizeof(struct meson_nand_page0));
>> +		shortm = 1;
>> +	} else
>> +		pages = len / nfc->param.ecc_size;
>> +
>> +	cmd = CMDRWGEN(NFC_CMD_M2N,
>> +		nfc->param.rand_mode, bch, shortm, pagesize, pages);
>> +
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +}
>> +
>> +static void meson_nfc_cmd_n2m(struct meson_nfc *nfc, int raw)
>> +{
>> +	u32 cmd, pagesize, pages, shortm = 0;
>> +	int bch = nfc->param.bch_mode;
>> +	int len = nfc->param.page_size;
>> +
>> +	pagesize = nfc->param.ecc_size;
>> +
>> +	if (unlikely(raw)) {
>> +		bch = NAND_ECC_NONE;
>> +		len = nfc->param.page_size + nfc->param.oob_size;
>> +		cmd = (len & 0x3fff) | (nfc->param.rand_mode << 19) |
>> +			NFC_CMD_N2M;
>> +		writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +		return;
>> +	}
>> +
>> +	if (unlikely(bch == NFC_ECC_BCH_SHORT)) {
>> +		bch = nfc->data->short_bch;
>> +		pagesize = 384 >> 3;
>> +		pages = len / nfc->param.ecc_size;
>> +		shortm = 1;
>> +	} else
>> +		pages = len / nfc->param.ecc_size;
>> +
>> +	cmd = CMDRWGEN(NFC_CMD_N2M,
>> +		nfc->param.rand_mode, bch, shortm, pagesize, pages);
>> +
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +}
> 
> Looks like there's a lot in common in meson_nfc_cmd_m2n() and
> meson_nfc_cmd_n2m(). Wouldn't it be better to have a single function and
> pass the direction.
> 
sure, good idea, will construct a meson_nfc_cmd_access() helper to do this

>> +
>> +static int meson_nfc_wait_cmd_finish(struct meson_nfc *nfc,
>> +					unsigned int timeout_ms)
>> +{
>> +	u32 cmd_size = 0;
>> +	int ret;
>> +
>> +	/* wait cmd fifo is empty */
>> +	ret = readl_poll_timeout(nfc->reg_base + NFC_REG_CMD,
>> +				cmd_size,
>> +				!((cmd_size >> 22) & 0x1f),
>> +				10, timeout_ms * 1000);
>> +	if (ret)
>> +		dev_err(nfc->dev, "wait for empty cmd FIFO time out\n");
>> +
>> +	return ret;
>> +}
>> +
>> +static int meson_nfc_wait_dma_finish(struct meson_nfc *nfc)
>> +{
>> +	meson_nfc_cmd_idle(nfc, 0);
>> +	meson_nfc_cmd_idle(nfc, 0);
> 
> Two calls to cmd_idle(), is this expected or a copy&paste error? If
> that's expected it definitely deserves a comment explaining why?
> 

yes, it is intentional

we will put these comments into the function.
	/*
         * The Nand flash controller is designed as two stages pipleline -
         *  a) fetch and b) excute.
         * So, there might be cases when the driver see command queue is
empty,
         * but the Nand flash controller still has two commands buffered,
         * one is fetched into NFC request queue (ready to run), and another
         * is actively executing.
         */


>> +
>> +	return meson_nfc_wait_cmd_finish(nfc, DMA_BUSY_TIMEOUT);
>> +}
>> +
>> +static inline struct meson_nfc_info_format *nfc_info_ptr(struct meson_nfc *nfc,
>> +	int index)
>> +{
>> +	return (struct meson_nfc_info_format *) &nfc->info_buf[index * 8];
>> +}
>> +
>> +static u8 *meson_nfc_oob_ptr(struct meson_nfc *nfc, int i)
>> +{
>> +	int x, len;
>> +	int ecc_bytes = nfc->param.ecc_bytes, temp = nfc->param.ecc_size;
>> +
>> +	x = i ? 16 : 0;
>> +	len = (nfc->param.oob_mode) ? (temp * (i + 1) + ecc_bytes * i + x) :
>> +				(temp * (i + 1) + (ecc_bytes + 2) * i);
>> +
>> +	return nfc->data_buf + len;
>> +}
>> +
>> +static u8 *meson_nfc_data_ptr(struct meson_nfc *nfc, int i)
>> +{
>> +	int len, x;
>> +	int temp = nfc->param.ecc_size + nfc->param.ecc_bytes;
>> +
>> +	x = i ? 16 : 0;
>> +	len = nfc->param.oob_mode ? (temp * i + x) : (temp + 2) * i;
>> +
>> +	return nfc->data_buf + len;
>> +}
>> +
>> +static void meson_nfc_prase_data_oob(struct meson_nfc *nfc, u8 *buf, u8 *oob)
>> +{
>> +	int i, oob_len = 0;
>> +	u8 *dsrc, *osrc;
>> +
>> +	for (i = 0; i < nfc->param.ecc_step; i++) {
>> +		if (buf) {
>> +			dsrc = meson_nfc_data_ptr(nfc, i);
>> +			memcpy(buf, dsrc, nfc->param.ecc_size);
>> +			buf += nfc->param.ecc_size;
>> +		}
>> +
>> +		if (nfc->param.oob_mode)
>> +			oob_len = (i) ? nfc->param.ecc_bytes :
>> +						nfc->param.ecc_bytes + 16;
>> +		else
>> +			oob_len = nfc->param.ecc_bytes + 2;
>> +
>> +		osrc = meson_nfc_oob_ptr(nfc, i);
>> +		memcpy(oob, osrc, oob_len);
>> +		oob += oob_len;
>> +	}
>> +}
>> +
>> +static void meson_nfc_format_data_oob(struct meson_nfc *nfc,
>> +						const u8 *buf, u8 *oob)
>> +{
>> +	int i, oob_len = 0;
>> +	u8 *dsrc, *osrc;
>> +
>> +	for (i = 0; i < nfc->param.ecc_step; i++) {
>> +		if (buf) {
>> +			dsrc = meson_nfc_data_ptr(nfc, i);
>> +			memcpy(dsrc, buf, nfc->param.ecc_size);
>> +			buf += nfc->param.ecc_size;
>> +		}
>> +
>> +		if (nfc->param.oob_mode)
>> +			oob_len = i ? nfc->param.ecc_bytes :
>> +						nfc->param.ecc_bytes + 16;
>> +		else
>> +			oob_len = nfc->param.ecc_bytes + 2;
>> +
>> +		osrc = meson_nfc_oob_ptr(nfc, i);
>> +		memcpy(osrc, oob, oob_len);
>> +		oob += oob_len;
>> +	}
>> +}
>> +
>> +static int meson_nfc_queue_rb(struct meson_nfc *nfc)
>> +{
>> +	u32 cmd, cfg;
>> +	int ret = 0;
>> +
>> +	init_completion(&nfc->completion);
>> +
>> +	cfg = readl(nfc->reg_base + NFC_REG_CFG);
>> +	cfg |= (1 << 21);
>> +	writel(cfg, nfc->reg_base + NFC_REG_CFG);
>> +
>> +	meson_nfc_cmd_idle(nfc, NAND_TWB_TIME_CYCLE);
>> +	cmd = nfc->param.chip_select | NFC_CMD_CLE | (NAND_CMD_STATUS & 0xff);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +	meson_nfc_cmd_idle(nfc, NAND_TWB_TIME_CYCLE);
>> +
>> +	cmd = NFC_CMD_RB | NFC_CMD_IO6 | (1 << 16) | (0x18 & 0x1f);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +	meson_nfc_cmd_idle(nfc, 2);
>> +
>> +	ret = wait_for_completion_timeout(&nfc->completion,
>> +					msecs_to_jiffies(1000));
>> +	if (ret == 0) {
>> +		dev_err(nfc->dev, "wait nand irq timeout\n");
>> +		ret = -1;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static void meson_nfc_set_user_byte(struct mtd_info *mtd,
>> +					struct nand_chip *chip, u8 *oob_buf)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	struct meson_nfc_info_format *info;
>> +	int i, count;
>> +
>> +	if (nfc->param.oob_mode) {
>> +		memcpy(nfc->info_buf, oob_buf, 16);
>> +		return;
>> +	}
>> +
>> +	for (i = 0, count = 0; i < chip->ecc.steps; i++, count += 2) {
>> +		info = nfc_info_ptr(nfc, i);
>> +		info->info_bytes =
>> +			oob_buf[count] | (oob_buf[count + 1] << 8);
>> +	}
>> +}
>> +
>> +static void meson_nfc_get_user_byte(struct mtd_info *mtd,
>> +					struct nand_chip *chip, u8 *oob_buf)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	struct meson_nfc_info_format *info;
>> +	int i, count;
>> +
>> +	if (nfc->param.oob_mode) {
>> +		memcpy(oob_buf,  nfc->info_buf, 16);
>> +		return;
>> +	}
>> +
>> +	for (i = 0, count = 0; i < chip->ecc.steps; i++, count += 2) {
>> +		info = nfc_info_ptr(nfc, i);
>> +		oob_buf[count] = info->info_bytes & 0xff;
>> +		oob_buf[count + 1] = (info->info_bytes >> 8) & 0xff;
>> +	}
>> +}
>> +
>> +static int meson_nfc_ecc_correct(struct mtd_info *mtd,
>> +						struct nand_chip *chip)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	struct meson_nfc_info_format *info;
>> +	u32 bitflips = 0, i;
>> +	u8 zero_cnt;
>> +
>> +	for (i = 0; i < nfc->param.ecc_step; i++) {
>> +		info = nfc_info_ptr(nfc, i);
>> +		if (info->ecc.eccerr_cnt == 0x3f) {
>> +			zero_cnt = info->zero_cnt & 0x3f;
>> +			if (nfc->param.rand_mode
>> +				&& (zero_cnt < nfc->param.ecc_max))
>> +				return ECC_CHECK_RETURN_FF;
>> +			mtd->ecc_stats.failed++;
>> +			continue;
>> +		}
>> +		mtd->ecc_stats.corrected += info->ecc.eccerr_cnt;
>> +		bitflips = max_t(u32, bitflips, info->ecc.eccerr_cnt);
>> +	}
>> +
>> +	return bitflips;
>> +}
>> +
>> +static inline u8 meson_nfc_read_byte(struct mtd_info *mtd)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	u32 cmd;
>> +
>> +	cmd = nfc->param.chip_select | NFC_CMD_DRD | 0;
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +
>> +	meson_nfc_cmd_idle(nfc, 0);
>> +	meson_nfc_cmd_idle(nfc, 0);
>> +
>> +	meson_nfc_wait_cmd_finish(nfc, 1000);
>> +
>> +	return readb(nfc->reg_base + NFC_REG_BUF);
>> +}
>> +
>> +static void meson_nfc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < len; i++)
>> +		buf[i] = meson_nfc_read_byte(mtd);
>> +}
>> +
>> +static void meson_nfc_write_byte(struct mtd_info *mtd, u8 byte)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
>> +	u32 cmd;
>> +
>> +	meson_nfc_cmd_idle(nfc, NAND_TWB_TIME_CYCLE);
>> +
>> +	cmd = nfc->param.chip_select | NFC_CMD_DWR | (byte & 0xff);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +
>> +	meson_nfc_cmd_idle(nfc, NAND_TWB_TIME_CYCLE);
>> +	meson_nfc_cmd_idle(nfc, 0);
>> +
>> +	meson_nfc_wait_cmd_finish(nfc, 1000);
>> +}
>> +
>> +static void meson_nfc_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < len; i++)
>> +		meson_nfc_write_byte(mtd, buf[i]);
>> +}
>> +
>> +static int meson_nfc_write_page_sub(struct mtd_info *mtd,
>> +		struct nand_chip *chip, const u8 *buf, int page, int raw)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	dma_addr_t daddr, iaddr;
>> +	u32 cmd;
>> +	int ret;
>> +
>> +	nand_prog_page_begin_op(chip, page, 0, NULL, 0);
>> +
>> +	daddr = dma_map_single(nfc->dev, (void *)nfc->data_buf,
>> +			mtd->writesize + mtd->oobsize, DMA_TO_DEVICE);
>> +	ret = dma_mapping_error(nfc->dev, daddr);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "dma mapping error\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	iaddr = dma_map_single(nfc->dev, (void *)nfc->info_buf,
>> +			nfc->param.ecc_step * PER_INFO_BYTE, DMA_TO_DEVICE);
>> +	ret = dma_mapping_error(nfc->dev, iaddr);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "dma mapping error\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	cmd = GENCMDDADDRL(NFC_CMD_ADL, daddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +	cmd = GENCMDDADDRH(NFC_CMD_ADH, daddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +
>> +	cmd = GENCMDIADDRL(NFC_CMD_AIL, iaddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +	cmd = GENCMDIADDRH(NFC_CMD_AIH, iaddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +
>> +	meson_nfc_cmd_seed(nfc, page);
>> +
>> +	meson_nfc_cmd_m2n(nfc, raw);
>> +
>> +	ret = meson_nfc_wait_dma_finish(nfc);
>> +
>> +	dma_unmap_single(nfc->dev, daddr,
>> +			mtd->writesize + mtd->oobsize, DMA_TO_DEVICE);
>> +	dma_unmap_single(nfc->dev, iaddr,
>> +			nfc->param.ecc_step * PER_INFO_BYTE, DMA_TO_DEVICE);
>> +
>> +	return nand_prog_page_end_op(chip);
>> +}
>> +
>> +static int meson_nfc_write_page_raw(struct mtd_info *mtd,
>> +	struct nand_chip *chip, const u8 *buf, int oob_required, int page)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	u8 *oob_buf = chip->oob_poi;
>> +
>> +	meson_nfc_format_data_oob(nfc, buf, oob_buf);
>> +
>> +	return meson_nfc_write_page_sub(mtd, chip, nfc->data_buf, page, 1);
>> +}
>> +
>> +static int meson_nfc_write_page_hwecc(struct mtd_info *mtd,
>> +				    struct nand_chip *chip, const u8 *buf,
>> +				    int oob_required, int page)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	u8 *oob_buf = chip->oob_poi;
>> +
>> +	memcpy(nfc->data_buf, buf, mtd->writesize);
>> +	meson_nfc_set_user_byte(mtd, chip, oob_buf);
>> +
>> +	return meson_nfc_write_page_sub(mtd, chip, nfc->data_buf, page, 0);
>> +}
>> +
>> +static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc, int raw)
>> +{
>> +	struct meson_nfc_info_format *info;
>> +	int neccpages, i;
>> +
>> +	neccpages = raw ? 1 : nfc->param.ecc_step;
>> +
>> +	for (i = 0; i < neccpages; i++) {
>> +		info = nfc_info_ptr(nfc, neccpages - 1);
>> +		if (info->ecc.completed == 0)
>> +			dev_err(nfc->dev, "seems eccpage is invalid\n");
>> +	}
>> +}
>> +
>> +static int meson_nfc_read_page_sub(struct mtd_info *mtd,
>> +	struct nand_chip *chip, const u8 *buf, int page, int raw)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	dma_addr_t daddr, iaddr;
>> +	u32 cmd;
>> +	int ret;
>> +
>> +	nand_read_page_op(chip, page, 0, NULL, 0);
>> +
>> +	daddr = dma_map_single(nfc->dev, nfc->data_buf,
>> +			mtd->writesize + mtd->oobsize, DMA_FROM_DEVICE);
>> +	ret = dma_mapping_error(nfc->dev, daddr);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "dma mapping error\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	iaddr = dma_map_single(nfc->dev, nfc->info_buf,
>> +			nfc->param.ecc_step * PER_INFO_BYTE, DMA_FROM_DEVICE);
>> +	ret = dma_mapping_error(nfc->dev, iaddr);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "dma mapping error\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	cmd = GENCMDDADDRL(NFC_CMD_ADL, daddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +	cmd = GENCMDDADDRH(NFC_CMD_ADH, daddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +
>> +	cmd = GENCMDIADDRL(NFC_CMD_AIL, iaddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +	cmd = GENCMDIADDRH(NFC_CMD_AIH, iaddr);
>> +	writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> +
>> +	meson_nfc_cmd_seed(nfc, page);
>> +
>> +	meson_nfc_cmd_n2m(nfc, raw);
>> +
>> +	ret = meson_nfc_wait_dma_finish(nfc);
>> +
>> +	meson_nfc_queue_rb(nfc);
>> +
>> +	meson_nfc_check_ecc_pages_valid(nfc, raw);
>> +
>> +	dma_unmap_single(nfc->dev, daddr,
>> +			mtd->writesize + mtd->oobsize, DMA_FROM_DEVICE);
>> +	dma_unmap_single(nfc->dev, iaddr,
>> +			nfc->param.ecc_step * PER_INFO_BYTE, DMA_FROM_DEVICE);
>> +
>> +	return ret;
>> +}
>> +
>> +static int meson_nfc_read_page_raw(struct mtd_info *mtd,
>> +	struct nand_chip *chip, u8 *buf, int oob_required, int page)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	u8 *oob_buf = chip->oob_poi;
>> +	int ret;	
>> +
>> +	ret = meson_nfc_read_page_sub(mtd, chip, nfc->data_buf, page, 1);
>> +	if (ret)
>> +		return ret;
>> +
>> +	meson_nfc_prase_data_oob(nfc, buf, oob_buf);
>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_nfc_read_page_hwecc(struct mtd_info *mtd,
>> +	struct nand_chip *chip, u8 *buf, int oob_required, int page)
>> +{
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	u8 *oob_buf = chip->oob_poi;
>> +	int ret;
>> +
>> +	ret = meson_nfc_read_page_sub(mtd, chip, nfc->data_buf, page, 0);
>> +	if (ret)
>> +		return ret;
>> +
>> +	meson_nfc_get_user_byte(mtd, chip, oob_buf);
>> +
>> +	ret = meson_nfc_ecc_correct(mtd, chip);
>> +	if (ret == ECC_CHECK_RETURN_FF) {
>> +		if (buf)
>> +			memset(buf, 0xff, mtd->writesize);
>> +
>> +		memset(oob_buf, 0xff, mtd->oobsize);
>> +		return 0;
>> +	}
>> +	if (buf && (buf != nfc->data_buf))
>> +		memcpy(buf, nfc->data_buf, mtd->writesize);
>> +
>> +	return ret;
>> +}
>> +
>> +static int meson_nfc_read_oob_raw(struct mtd_info *mtd,
>> +				struct nand_chip *chip, int page)
>> +{
>> +	return meson_nfc_read_page_raw(mtd, chip, NULL, 1, page);
>> +}
>> +
>> +static int meson_nfc_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
>> +				int page)
>> +{
>> +	return meson_nfc_read_page_hwecc(mtd, chip, NULL, 1, page);
>> +}
>> +
>> +static int meson_ooblayout_ecc(struct mtd_info *mtd, int section,
>> +				  struct mtd_oob_region *oobregion)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +	int free_oob;
>> +
>> +	if (section > chip->ecc.steps)
> 
> 	if (section >= chip->ecc.steps)
> 
sure, will fix
>> +		return -ERANGE;
>> +
>> +	free_oob = nfc->param.oob_mode ? 16 : (chip->ecc.steps * 2);
> 
> Hm, are you sure all free OOB bytes are placed at the beginning of the
> OOB buffer? Shouldn't it be section * 2 instead of chip->ecc.steps * 2?
> 
> 	

you're right here, we will fix this

> 
>> +	oobregion->offset = section * chip->ecc.bytes + free_oob;
>> +	oobregion->length = chip->ecc.bytes;
>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_ooblayout_free(struct mtd_info *mtd, int section,
>> +				   struct mtd_oob_region *oobregion)
>> +{
>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>> +	struct meson_nfc *nfc = nand_get_controller_data(chip);
>> +
>> +	if (section > chip->ecc.steps)
> 
> 	if (section >= chip->ecc.steps)
> 
sure, will fix

>> +		return -ERANGE;
>> +
>> +	oobregion->offset = 0;
>> +	oobregion->length = nfc->param.oob_mode ? 16 : (chip->ecc.steps * 2);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct mtd_ooblayout_ops meson_ooblayout_ops = {
>> +	.ecc = meson_ooblayout_ecc,
>> +	.free = meson_ooblayout_free,
>> +};
>> +
>> +static int meson_nfc_ecc_init(struct device *dev, struct mtd_info *mtd)
>> +{
>> +	struct nand_chip *nand = mtd_to_nand(mtd);
>> +	struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>> +	struct meson_nfc *nfc = nand_get_controller_data(nand);
>> +	struct meson_nand_ecc *meson_ecc = nfc->data->ecc;
>> +	int num = nfc->data->ecc_num;
>> +	int nsectors, i, bytes;
>> +
>> +	/* support only ecc hw mode */
>> +	if (nand->ecc.mode != NAND_ECC_HW) {
> 
> Given that you support raw accesses, I'm pretty sure you can support
> ECC_NONE, ECC_SOFT and ECC_ON_DIE with zero effort.
> 

is this a block for this driver to be accepted by upstream?
otherwise we'd like to implement this feature later in separate patch.


>> +		dev_err(dev, "ecc.mode not supported\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (!nand->ecc.size || !nand->ecc.strength) {
>> +		/* use datasheet requirements */
>> +		nand->ecc.strength = nand->ecc_strength_ds;
>> +		nand->ecc.size = nand->ecc_step_ds;
>> +	}
>> +
>> +	if (nand->ecc.options & NAND_ECC_MAXIMIZE) {
>> +		nand->ecc.size = 1024;
>> +		nsectors = mtd->writesize / nand->ecc.size;
>> +
>> +		/* Reserve 2 bytes for each ecc page */
>> +		if (meson_chip->user_mode == NFC_USER2_OOB_BYTES)
>> +			bytes = mtd->oobsize - 2 * nsectors;
>> +		else
>> +			bytes = mtd->oobsize - 16;
>> +
>> +		bytes /= nsectors;
>> +
>> +		/* and bytes has to be even. */
>> +		if (bytes % 2)
>> +			bytes--;
>> +
>> +		nand->ecc.strength = bytes * 8 / fls(8 * nand->ecc.size);
>> +	} else {
>> +		if (nand->ecc.strength > meson_ecc[num - 1].strength) {
>> +			dev_err(dev, "not support ecc strength\n");
>> +			return -EINVAL;
>> +		}
>> +	}
>> +
>> +	for (i = 0; i < num; i++) {
>> +		if ((meson_ecc[i].strength == 0xff)
>> +			|| (nand->ecc.strength < meson_ecc[i].strength))
>> +			break;
>> +	}
>> +
>> +	if (!i) {
>> +		nand->ecc.strength = 0;
>> +	} else {
>> +		nand->ecc.strength = meson_ecc[i - 1].strength;
>> +		nand->ecc.bytes = meson_ecc[i - 1].parity;
>> +	}
>> +
>> +	meson_chip->bch_mode = meson_ecc[i - 1].bch;
>> +
>> +	if (nand->ecc.size != 512 && nand->ecc.size != 1024)
>> +		return -EINVAL;
>> +
>> +	nsectors = mtd->writesize / nand->ecc.size;
>> +	bytes =(meson_chip->user_mode == NFC_USER2_OOB_BYTES) ? nsectors * 2 : 16;
>> +	if (mtd->oobsize < (nand->ecc.bytes * nsectors + bytes))
>> +		return -EINVAL;
> 
> It's probably worth looking at what is being proposed here [2] for the
> ECC config selection logic.
> 

sure, we'd happy to adopt the ECC config helper function, and seems it
is possible ;-)

sounds the proposed ECC config patch is still under review, and we
would like to adjust our code once it's ready (probably we will still
keep this version in patch v2, then address it in v3 later)


>> +
>> +	return 0;
>> +}
>> +
>> +static const char * sd_emmc_ext_clk0_parent_names[MUX_CLK_NUM_PARENTS];
>> +
>> +static struct clk_regmap sd_emmc_c_ext_clk0_sel = {
>> +	.data = &(struct clk_regmap_mux_data){
>> +		.offset = SD_EMMC_CLOCK,
>> +		.mask = 0x3,
>> +		.shift = 6,
>> +	},
>> +	.hw.init = &(struct clk_init_data) {
>> +		.name = "sd_emmc_c_nand_clk_mux",
>> +		.ops = &clk_regmap_mux_ops,
>> +		.parent_names = sd_emmc_ext_clk0_parent_names,
>> +		.num_parents = ARRAY_SIZE(sd_emmc_ext_clk0_parent_names),
>> +		.flags = CLK_SET_RATE_PARENT,
>> +	},
>> +};
>> +
>> +static struct clk_regmap sd_emmc_c_ext_clk0_div = {
>> +	.data = &(struct clk_regmap_div_data){
>> +		.offset = SD_EMMC_CLOCK,
>> +		.shift = 0,
>> +		.width = 6,
>> +		.flags = CLK_DIVIDER_ROUND_CLOSEST | CLK_DIVIDER_ONE_BASED,
>> +	},
>> +	.hw.init = &(struct clk_init_data) {
>> +		.name = "sd_emmc_c_nand_clk_div",
>> +		.ops = &clk_regmap_divider_ops,
>> +		.parent_names = (const char *[]){ "sd_emmc_c_nand_clk_mux" },
>> +		.num_parents = 1,
>> +		.flags = CLK_SET_RATE_PARENT,
>> +	},
>> +};
>> +
>> +static int meson_nfc_clk_init(struct meson_nfc *nfc)
>> +{
>> +	struct clk_regmap *mux = &sd_emmc_c_ext_clk0_sel;
>> +	struct clk_regmap *div = &sd_emmc_c_ext_clk0_div;
>> +	struct clk *clk;
>> +	int i, ret;
>> +
>> +	/* request core clock */
>> +	nfc->core_clk = devm_clk_get(nfc->dev, "core");
>> +	if (IS_ERR(nfc->core_clk)) {
>> +		dev_err(nfc->dev, "failed to get core clk\n");
>> +		return PTR_ERR(nfc->core_clk);
>> +	}
>> +
>> +	/* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
>> +	regmap_update_bits(nfc->reg_clk, 0,
>> +			CLK_SELECT_NAND | CLK_ALWAYS_ON | CLK_DIV_MASK,
>> +			CLK_SELECT_NAND | CLK_ALWAYS_ON | CLK_DIV_MASK);
>> +
>> +	/* get the mux parents */
>> +	for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
>> +		char name[16];
>> +
>> +		snprintf(name, sizeof(name), "clkin%d", i);
>> +		clk = devm_clk_get(nfc->dev, name);
>> +		if (IS_ERR(clk)) {
>> +			if (clk != ERR_PTR(-EPROBE_DEFER))
>> +				dev_err(nfc->dev, "Missing clock %s\n", name);
>> +			return PTR_ERR(clk);
>> +		}
>> +
>> +		sd_emmc_ext_clk0_parent_names[i] = __clk_get_name(clk);
>> +	}
>> +
>> +	mux->map = nfc->reg_clk;
>> +	clk = devm_clk_register(nfc->dev, &mux->hw);
>> +	if (WARN_ON(IS_ERR(clk)))
>> +		return PTR_ERR(clk);
>> +
>> +	div->map = nfc->reg_clk;
>> +	nfc->device_clk = devm_clk_register(nfc->dev, &div->hw);
>> +	if (WARN_ON(IS_ERR(nfc->device_clk)))
>> +		return PTR_ERR(nfc->device_clk);
>> +
>> +	ret = clk_prepare_enable(nfc->core_clk);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "failed to enable core clk\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = clk_prepare_enable(nfc->device_clk);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "failed to enable device clk\n");
>> +		clk_disable_unprepare(nfc->core_clk);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
> 
> 
> As said above, I don't like having a clk driver here, especially since
> the registers you're accessing are not part of the NAND controller
> registers. Please try to create a driver in drivers/clk/ for that.
> 

already addressed this as in preivous comment

>> +
>> +static void meson_nfc_disable_clk(struct meson_nfc *nfc)
>> +{
>> +	clk_disable_unprepare(nfc->device_clk);
>> +	clk_disable_unprepare(nfc->core_clk);
>> +}
>> +
>> +static int meson_nfc_buffer_init(struct mtd_info *mtd)
>> +{
>> +	struct nand_chip *nand = mtd_to_nand(mtd);
>> +	struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>> +	struct meson_nfc *nfc = nand_get_controller_data(nand);
>> +	struct device *dev = nfc->dev;
>> +	int info_bytes, page_bytes;
>> +	int nsectors;
>> +
>> +	nsectors = mtd->writesize / nand->ecc.size;
>> +	info_bytes = nsectors * PER_INFO_BYTE;
>> +	page_bytes = mtd->writesize + mtd->oobsize;
>> +
>> +	if ((meson_chip->data_buf) && (meson_chip->info_buf))
>> +		return 0;
>> +
>> +	meson_chip->data_buf = devm_kzalloc(dev, page_bytes, GFP_KERNEL);
>> +	if (!meson_chip->data_buf)
>> +		return  -ENOMEM;
>> +
>> +	meson_chip->info_buf = devm_kzalloc(dev, info_bytes, GFP_KERNEL);
>> +	if (!meson_chip->info_buf)
>> +		return  -ENOMEM;
> 
> You're doing DMA on those buffers, and devm_kzalloc() is not
> DMA-friendly (returned buffers are not aligned on a cache line). Also,
> you don't have to allocate your own buffers because the core already
> allocate them (chip->data_buf, chip->oob_poi). All you need to do is
> set the NAND_USE_BOUNCE_BUFFER flag in chip->options to make sure
> you're always passed a DMA-able buffer.
> 

thanks for the suggestion, we've migrated to use the
dmam_alloc_coherent() API


>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_nfc_calc_set_timing(struct meson_nfc *nfc,
>> +				int rc_min, int rea_max, int rhoh_min)
>> +{
>> +	int div, bt_min, bt_max, bus_timing;
>> +	int ret;
>> +
>> +	div = DIV_ROUND_UP((rc_min / 1000), NFC_CLK_CYCLE);
>> +	ret = clk_set_rate(nfc->device_clk, 1000000000 / div);
>> +	if (ret) {
>> +		dev_err(nfc->dev, "failed to set nand clock rate\n");
>> +		return ret;
>> +	}
>> +
>> +	bt_min = (rea_max + NFC_DEFAULT_DELAY) / div;
>> +	bt_max = (NFC_DEFAULT_DELAY + rhoh_min + rc_min / 2) / div;
>> +
>> +	bt_min = DIV_ROUND_UP(bt_min, 1000);
>> +	bt_max = DIV_ROUND_UP(bt_max, 1000);
>> +
>> +	if (bt_max < bt_min)
>> +		return -EINVAL;
>> +
>> +	bus_timing = (bt_min + bt_max) / 2 + 1;
>> +
>> +	writel((1 << 21), nfc->reg_base + NFC_REG_CFG);
>> +	writel((NFC_CLK_CYCLE - 1) | (bus_timing << 5),
>> +				nfc->reg_base + NFC_REG_CFG);
>> +
>> +	writel((1 << 31), nfc->reg_base + NFC_REG_CMD);
>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_nfc_setup_data_interface(struct mtd_info *mtd, int csline,
>> +				const struct nand_data_interface *conf)
>> +{
>> +	struct nand_chip *nand = mtd_to_nand(mtd);
>> +	struct meson_nfc *nfc = nand_get_controller_data(nand);
>> +	const struct nand_sdr_timings *timings;
>> +
>> +	timings = nand_get_sdr_timings(conf);
>> +	if (IS_ERR(timings))
>> +		return -ENOTSUPP;
>> +
>> +	if (csline == NAND_DATA_IFACE_CHECK_ONLY)
>> +		return 0;
>> +
>> +	meson_nfc_calc_set_timing(nfc, timings->tRC_min,
>> +				timings->tREA_max, timings->tRHOH_min);
>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_nfc_get_nand_chip_dts(struct meson_nfc *nfc,
>> +		struct meson_nfc_nand_chip *chip, struct device_node *np)
>> +{
>> +	struct device *dev = nfc->dev;
>> +
>> +	if (of_property_read_u32(np, "reg", &chip->cs)) {
>> +		dev_err(dev, "can not get ce number\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (chip->cs > MAX_CE_NUM) {
>> +		dev_err(dev, "ce number is beyond\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (of_property_read_u32(np, "meson-nand-user-mode", &chip->user_mode)) {
>> +		dev_err(dev, "can not get user oob mode\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if ((chip->user_mode != NFC_USER2_OOB_BYTES)
>> +			|| (chip->user_mode != NFC_USER16_OOB_BYTES))
>> +		chip->user_mode = NFC_USER2_OOB_BYTES;
>> +
>> +	if (of_property_read_u32(np, "meson-nand-ran-mode", &chip->rand_mode)) {
>> +		dev_err(dev, "can not get scramble mode\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_nfc_nand_chip_init(struct device *dev, struct meson_nfc *nfc,
>> +				  struct device_node *np)
>> +{
>> +	struct meson_nfc_nand_chip *chip;
>> +	struct nand_chip *nand;
>> +	struct mtd_info *mtd;
>> +	int ret;
>> +
>> +	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
>> +	if (!chip)
>> +		return -ENOMEM;
>> +
>> +	ret = meson_nfc_get_nand_chip_dts(nfc, chip, np);
> 
> Is there a really a need for putting this code in a separate function?
> Do you plan to support non-DT platforms?
> 

No, we don't plan to support non-DT platfrom, will fix this


>> +	if (ret)
>> +		return ret;
>> +
>> +	nand = &chip->nand;
>> +	nand_set_flash_node(nand, np);
>> +	nand_set_controller_data(nand, nfc);
>> +
>> +	nand->options |= NAND_USE_BOUNCE_BUFFER;
>> +	nand->select_chip = meson_nfc_select_chip;
>> +	nand->write_byte = meson_nfc_write_byte;
>> +	nand->write_buf = meson_nfc_write_buf;
>> +	nand->read_byte = meson_nfc_read_byte;
>> +	nand->read_buf = meson_nfc_read_buf;
>> +	nand->cmd_ctrl = meson_nfc_cmd_ctrl;
> 
> ->{write,read}_byte(), ->{write,read}_buf(), ->cmd_ctrl() should be
> replaced by ->exec_op().
> 

we have implemented a version of exec_op() , we really appreciate if you
can help to review this.

>> +	nand->setup_data_interface = meson_nfc_setup_data_interface;
>> +
>> +	nand->chip_delay = 200;
> 
> This should not be needed if you implement ->exec_op() and
> ->setup_data_interface().
> 
will drop this

>> +	nand->ecc.mode = NAND_ECC_HW;
>> +
>> +	nand->ecc.write_page_raw = meson_nfc_write_page_raw;
>> +	nand->ecc.write_page = meson_nfc_write_page_hwecc;
>> +	nand->ecc.write_oob_raw = nand_write_oob_std;
>> +	nand->ecc.write_oob = nand_write_oob_std;
>> +
>> +	nand->ecc.read_page_raw = meson_nfc_read_page_raw;
>> +	nand->ecc.read_page = meson_nfc_read_page_hwecc;
>> +	nand->ecc.read_oob_raw = meson_nfc_read_oob_raw;
>> +	nand->ecc.read_oob = meson_nfc_read_oob;
>> +
>> +	mtd = nand_to_mtd(nand);
>> +	mtd->owner = THIS_MODULE;
>> +	mtd->dev.parent = dev;
>> +	mtd->name = devm_kasprintf(nfc->dev, GFP_KERNEL,
>> +				   "%s:nand", dev_name(dev));
>> +	if (!mtd->name) {
>> +		dev_err(nfc->dev, "Failed to allocate mtd->name\n");
>> +		return -ENOMEM;
>> +	}
> 
> You set the name after nand_scan_ident() and make it conditional (only
> if ->name == NULL) so that the label property defined in the DT takes
> precedence over the default name.

we can do this, but as second consideration, we'd prefer simply to drop
this customization of mtd->name here (we didn't understand your next cs
id suggestion).

> Also, I recommend suffixing this name
> with the CS id, just in case you ever need to support connecting several
> chips to the same controller. 
> 

we actually didn't get the point here, cs is about chip selection with
multiple nand chip? and how to get this information?


>> +
>> +	mtd_set_ooblayout(mtd, &meson_ooblayout_ops);
> 
> We usually assign the OOB layout when we know which ECC engine will be
> used. Here that works because you only support ECC_HW, but I think it's
> preferable to move that in your ECC init function.
> 

Ok, will do

>> +
>> +	ret = nand_scan_ident(mtd, 1, NULL);
>> +	if (ret) {
>> +		dev_err(dev, "failed to can ident\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/* store bbt magic in page, cause OOB is not protected */
>> +	if (nand->bbt_options & NAND_BBT_USE_FLASH)
>> +		nand->bbt_options |= NAND_BBT_NO_OOB;
>> +
>> +	nand->options |= NAND_NO_SUBPAGE_WRITE;
>> +
>> +	ret = meson_nfc_ecc_init(dev, mtd);
>> +	if (ret) {
>> +		dev_err(dev, "failed to ecc init\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (nand->options & NAND_BUSWIDTH_16) {
>> +		dev_err(dev, "16bits buswidth not supported");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = meson_nfc_buffer_init(mtd);
>> +	if (ret)
>> +		return -ENOMEM;
>> +
>> +	ret = nand_scan_tail(mtd);
>> +	if (ret)
>> +		return -ENODEV;
>> +
>> +	ret = mtd_device_register(mtd, NULL, 0);
>> +	if (ret) {
>> +		dev_err(dev, "failed to register mtd device: %d\n", ret);
>> +		nand_release(mtd);
> 
> You should call nand_cleanup() not call nand_release().
> 
ok, will fix

>> +		return ret;
>> +	}
>> +
>> +	list_add_tail(&chip->node, &nfc->chips);
>> +
>> +	return 0;
>> +}
>> +
>> +static int meson_nfc_nand_chips_init(struct device *dev, struct meson_nfc *nfc)
>> +{
>> +	struct device_node *np = dev->of_node;
>> +	struct device_node *nand_np;
>> +	int ret;
>> +
>> +	for_each_child_of_node(np, nand_np) {
>> +		ret = meson_nfc_nand_chip_init(dev, nfc, nand_np);
>> +		if (ret) {
>> +			of_node_put(nand_np);
> 
> You don't need to call of_node_put(), for_each_child_of_node() will do
> that for you.
> 

ok, will drop this


>> +			return ret;
> 
> You should remove all chips that have been added in case of error.
> 
will fix this.

>> +		}
>> +	}
>> +	return 0;
>> +}
>> +
>> +static irqreturn_t meson_nfc_irq(int irq, void *id)
>> +{
>> +	struct meson_nfc *nfc = id;
>> +	u32 cfg;
>> +
>> +	cfg = readl(nfc->reg_base + NFC_REG_CFG);
>> +	cfg |= (1 << 21);
>> +	writel(cfg, nfc->reg_base + NFC_REG_CFG);
>> +
>> +	complete(&nfc->completion);
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static const struct meson_nfc_data meson_gxl_data = {
>> +	.short_bch	= NFC_ECC_BCH60_1K,
>> +	.ecc		= meson_gxl_ecc,
>> +	.ecc_num	= ARRAY_SIZE(meson_gxl_ecc),
>> +};
>> +
>> +static const struct meson_nfc_data meson_axg_data = {
>> +	.short_bch	= NFC_ECC_BCH8_1K,
>> +	.ecc		= meson_axg_ecc,
>> +	.ecc_num	= ARRAY_SIZE(meson_axg_ecc),
>> +};
>> +
>> +static const struct of_device_id meson_nfc_id_table[] = {
>> +	{
>> +		.compatible = "amlogic,meson-gxl-nfc",
>> +		.data = &meson_gxl_data,
>> +	}, {
>> +		.compatible = "amlogic,meson-axg-nfc",
>> +		.data = &meson_axg_data,
>> +	},
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(of, meson_nfc_id_table);
>> +
>> +static int meson_nfc_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct meson_nfc *nfc;
>> +	struct resource *res;
>> +	const struct of_device_id *of_nfc_id;
>> +	int ret, irq;
>> +
>> +	nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
>> +	if (!nfc)
>> +		return -ENOMEM;
>> +
>> +	of_nfc_id = of_match_device(meson_nfc_id_table, &pdev->dev);
>> +	if (!of_nfc_id)
>> +		return -ENODEV;
>> +
>> +	nfc->data = (struct meson_nfc_data *)of_nfc_id->data;
>> +
>> +	spin_lock_init(&nfc->controller.lock);
>> +	init_waitqueue_head(&nfc->controller.wq);
>> +	INIT_LIST_HEAD(&nfc->chips);
>> +
>> +	nfc->dev = dev;
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	if (!res) {
>> +		dev_err(dev, "Failed to nfc reg resource\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	nfc->reg_base = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(nfc->reg_base)) {
>> +		dev_err(dev, "Failed to lookup nfi reg base\n");
>> +		return PTR_ERR(nfc->reg_base);
>> +	}
>> +
>> +	nfc->reg_clk = syscon_regmap_lookup_by_phandle(dev->of_node,
>> +							"amlogic,mmc-syscon");
>> +	if (IS_ERR(nfc->reg_clk)) {
>> +		dev_err(dev, "Failed to lookup clock base\n");
>> +		return PTR_ERR(nfc->reg_clk);
>> +	}
>> +
>> +	irq = platform_get_irq(pdev, 0);
>> +	if (irq < 0) {
>> +		dev_err(dev, "no nfi irq resource\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	ret = meson_nfc_clk_init(nfc);
>> +	if (ret) {
>> +		dev_err(dev, "failed to initialize nand clk\n");
>> +		goto err_clk;
>> +	}
>> +
>> +	ret = devm_request_irq(dev, irq, meson_nfc_irq, 0, dev_name(dev), nfc);
>> +	if (ret) {
>> +		dev_err(dev, "failed to request nfi irq\n");
>> +		ret = -EINVAL;
>> +		goto err_clk;
>> +	}
>> +
>> +	ret = dma_set_mask(dev, DMA_BIT_MASK(32));
>> +	if (ret) {
>> +		dev_err(dev, "failed to set dma mask\n");
>> +		goto err_clk;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, nfc);
>> +
>> +	ret = meson_nfc_nand_chips_init(dev, nfc);
>> +	if (ret) {
>> +		dev_err(dev, "failed to init nand chips\n");
>> +		goto err_clk;
>> +	}
>> +
>> +	meson_nfc_page0_gen(nfc);
>> +	return 0;
>> +
>> +err_clk:
>> +	clk_disable_unprepare(nfc->device_clk);
>> +	clk_disable_unprepare(nfc->core_clk);
> 
> Why not meson_nfc_disable_clk()?
> 

good idea, will fix

>> +
>> +	return ret;
>> +}
>> +
>> +static int meson_nfc_remove(struct platform_device *pdev)
>> +{
>> +	struct meson_nfc *nfc = platform_get_drvdata(pdev);
>> +	struct meson_nfc_nand_chip *chip;
>> +
>> +	while (!list_empty(&nfc->chips)) {
>> +		chip = list_first_entry(&nfc->chips, struct meson_nfc_nand_chip,
>> +					node);
>> +		nand_release(nand_to_mtd(&chip->nand));
> 
> Please use mtd_device_unregister() + nand_cleanup(), and check the
> return value of mtd_device_unregister() before calling nand_cleanup().
> 
Ok

>> +		list_del(&chip->node);
>> +	}
>> +
>> +	meson_nfc_disable_clk(nfc);
>> +
>> +	platform_set_drvdata(pdev, NULL);
>> +
>> +	return 0;
>> +}
>> +
>> +static struct platform_driver meson_nfc_driver = {
>> +	.probe  = meson_nfc_probe,
>> +	.remove = meson_nfc_remove,
>> +	.driver = {
>> +		.name  = "meson_nand",
> 
> If you don't mind, I prefer "meson-nand" :-).
sure

> 
>> +		.of_match_table = meson_nfc_id_table,
>> +	},
>> +};
>> +
> 
> Can you remove this blank line?
> 
sure

>> +module_platform_driver(meson_nfc_driver);
>> +
>> +MODULE_LICENSE("Dual MIT/GPL");
>> +MODULE_AUTHOR("Liang Yang <liang.yang at amlogic.com>");
>> +MODULE_DESCRIPTION("Amlogic's Meson NAND Flash Controller driver");
> 
> I probably missed a lot of other things, but that should be enough to
> start working on a v2.
> 
thanks a lot for the review

> Regards,
> 
> Boris
> 
> [1]https://elixir.bootlin.com/u-boot/v2018.07-rc2/source/tools/sunxi-spl-image-builder.c
> [2]http://patchwork.ozlabs.org/patch/931984/
> 
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