Date:	Thu, 21 Jul 2016 14:35:55 -0500
From:	Han Xu <xhnjupt@...il.com>
To:	Yunhui Cui <B56489@...escale.com>
Cc:	David Woodhouse <dwmw2@...radead.org>,
	Brian Norris <computersforpeace@...il.com>,
	"han.xu@...escale.com" <han.xu@...escale.com>,
	Yunhui Cui <yunhui.cui@....com>,
	"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Yao Yuan <yao.yuan@....com>
Subject: Re: [PATCH v2 6/9] mtd: spi-nor: Support R/W for S25FS-S family flash

On Fri, Apr 22, 2016 at 1:39 AM, Yunhui Cui <B56489@...escale.com> wrote:
> From: Yunhui Cui <yunhui.cui@....com>
>
> With the physical sectors combination, S25FS-S family flash
> requires some special operations for read/write functions.
>
> Signed-off-by: Yunhui Cui <yunhui.cui@....com>
> ---
>  drivers/mtd/spi-nor/spi-nor.c | 59 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 157841d..91ee920 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -39,6 +39,10 @@
>
>  #define SPI_NOR_MAX_ID_LEN     6
>  #define SPI_NOR_MAX_ADDR_WIDTH 4
> +/* Added for S25FS-S family flash */
> +#define SPINOR_CONFIG_REG3_OFFSET      0x800004
> +#define CR3V_4KB_ERASE_UNABLE  0x8
> +#define SPINOR_S25FS_FAMILY_ID 0x81
>
>  struct flash_info {
>         char            *name;
> @@ -78,6 +82,7 @@ struct flash_info {
>  };
>
>  #define JEDEC_MFR(info)        ((info)->id[0])
> +#define EXT_ID(info)   ((info)->id[5])
>
>  static const struct flash_info *spi_nor_match_id(const char *name);
>
> @@ -881,6 +886,7 @@ static const struct flash_info spi_nor_ids[] = {
>          */
>         { "s25sl032p",  INFO(0x010215, 0x4d00,  64 * 1024,  64, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
>         { "s25sl064p",  INFO(0x010216, 0x4d00,  64 * 1024, 128, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> +       { "s25fs256s1", INFO6(0x010219, 0x4d0181, 64 * 1024, 512, 0)},
>         { "s25fl256s0", INFO(0x010219, 0x4d00, 256 * 1024, 128, 0) },
>         { "s25fl256s1", INFO(0x010219, 0x4d01,  64 * 1024, 512, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
>         { "s25fl512s",  INFO(0x010220, 0x4d00, 256 * 1024, 256, SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> @@ -1018,6 +1024,53 @@ static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
>         return ERR_PTR(-ENODEV);
>  }
>
> +/*
> + * The S25FS-S family physical sectors may be configured as a
> + * hybrid combination of eight 4-kB parameter sectors
> + * at the top or bottom of the address space with all
> + * but one of the remaining sectors being uniform size.
> + * The Parameter Sector Erase commands (20h or 21h) must
> + * be used to erase the 4-kB parameter sectors individually.
> + * The Sector (uniform sector) Erase commands (D8h or DCh)
> + * must be used to erase any of the remaining
> + * sectors, including the portion of highest or lowest address
> + * sector that is not overlaid by the parameter sectors.
> + * The uniform sector erase command has no effect on parameter sectors.
> + */
> +static int spansion_s25fs_disable_4kb_erase(struct spi_nor *nor)
> +{
> +       struct fsl_qspi *q;
> +       u32 cr3v_addr  = SPINOR_CONFIG_REG3_OFFSET;
> +       u8 cr3v = 0x0;
> +       int ret = 0x0;
> +
> +       q = nor->priv;
> +
> +       nor->cmd_buf[2] = cr3v_addr >> 16;
> +       nor->cmd_buf[1] = cr3v_addr >> 8;
> +       nor->cmd_buf[0] = cr3v_addr >> 0;
> +
> +       ret = nor->read_reg(nor, SPINOR_OP_SPANSION_RDAR, &cr3v, 1);

I feel it's hacking code.

Hi Brian, do we have any plan to support this special case? The RDAR(
Read Any Register) needs an extra address parameter.

> +       if (ret)
> +               return ret;
> +       if (cr3v & CR3V_4KB_ERASE_UNABLE)
> +               return 0;
> +       ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0);
> +       if (ret)
> +               return ret;
> +       cr3v = CR3V_4KB_ERASE_UNABLE;
> +       nor->program_opcode = SPINOR_OP_SPANSION_WRAR;
> +       nor->write(nor, cr3v_addr, 1, NULL, &cr3v);
> +
> +       ret = nor->read_reg(nor, SPINOR_OP_SPANSION_RDAR, &cr3v, 1);
> +       if (ret)
> +               return ret;
> +       if (!(cr3v & CR3V_4KB_ERASE_UNABLE))
> +               return -EPERM;
> +
> +       return 0;
> +}
> +
>  static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
>                         size_t *retlen, u_char *buf)
>  {
> @@ -1311,6 +1364,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
>                 spi_nor_wait_till_ready(nor);
>         }
>
> +       if (EXT_ID(info) == SPINOR_S25FS_FAMILY_ID) {
> +               ret = spansion_s25fs_disable_4kb_erase(nor);
> +               if (ret)
> +                       return ret;
> +       }
> +
>         if (!mtd->name)
>                 mtd->name = dev_name(dev);
>         mtd->priv = nor;
> --
> 2.1.0.27.g96db324
>
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/



-- 
Sincerely,

Han XU

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