Re: [PATCH 4/5] mtd: spi-nor: Move clear_sr_bp() to 'struct spi_nor_flash_parameter'

Boris Brezillon
2019-08-25T13:09:34Z

On Fri, 23 Aug 2019 15:53:41 +0000
<Tudor.Ambarus@microchip.com> wrote:

> From: Tudor Ambarus <tudor.ambarus@microchip.com>
>
> All flash parameters and settings should reside inside
> 'struct spi_nor_flash_parameter'. Move clear_sr_bp() from
> 'struct spi_nor' to 'struct spi_nor_flash_parameter'.
>
> Rename clear_sr_bp()/disable_block_protection() to better indicate
> what the function does.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> drivers/mtd/spi-nor/spi-nor.c | 47 +++++++++++++++++++++++++++++++++----------
> include/linux/mtd/spi-nor.h | 5 ++---
> 2 files changed, 38 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> index 6bd104c29cd9..15b0b1148bf3 100644
> --- a/drivers/mtd/spi-nor/spi-nor.c
> +++ b/drivers/mtd/spi-nor/spi-nor.c
> @@ -4477,20 +4477,45 @@ static int spi_nor_quad_enable(struct spi_nor *nor)
> return nor->params.quad_enable(nor);
> }
>
> +/**
> + * spi_nor_disable_block_protection() - Disable the write block protection
> + * during power-up.
> + * @nor: pointer to a 'struct spi_nor'
> + *
> + * Some spi-nor flashes are write protected by default after a power-on reset
> + * cycle, in order to avoid inadvertend writes during power-up. Backward
> + * compatibility imposes to disable the write block protection at power-up
> + * by default.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_disable_block_protection(struct spi_nor *nor)
> +{
> + if (!nor->params.disable_block_protection)
> + return 0;
> +
> + /*
> + * In case of the legacy quad enable requirements are set, if the
> + * configuration register Quad Enable bit is one, only the the
> + * Write Status (01h) command with two data bytes may be used to clear
> + * the block protection bits.
> + */
> + if (nor->params.quad_enable == spansion_quad_enable)
> + nor->params.disable_block_protection =
> + spi_nor_spansion_clear_sr_bp;

Hm, doesn't look right to adjust the function pointer just before
calling it. Can't we move that logic earlier (when doing the
default/manufacturer specific init)? Also, as I said in one of my
previous emails, I'd prefer to have this hook moved to
spi_nor_locking_ops and just have a flag to reflect when block
protection can be disabled.

> +
> + return nor->params.disable_block_protection(nor);
> +}
> +
> static int spi_nor_init(struct spi_nor *nor)
> {
> int err;
>
> - if (nor->clear_sr_bp) {
> - if (nor->quad_enable == spansion_quad_enable)
> - nor->clear_sr_bp = spi_nor_spansion_clear_sr_bp;
> -
> - err = nor->clear_sr_bp(nor);
> - if (err) {
> - dev_err(nor->dev,
> - "fail to clear block protection bits\n");
> - return err;
> - }
> + err = spi_nor_disable_block_protection(nor);
> + if (err) {
> + dev_err(nor->dev,
> + "fail to unlock the flash at init (err = %d)\n", err);
> + return err;
> }
>
> err = spi_nor_quad_enable(nor);
> @@ -4635,7 +4660,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> JEDEC_MFR(nor->info) == SNOR_MFR_INTEL ||
> JEDEC_MFR(nor->info) == SNOR_MFR_SST ||
> nor->info->flags & SPI_NOR_HAS_LOCK)
> - nor->clear_sr_bp = spi_nor_clear_sr_bp;
> + nor->params.disable_block_protection = spi_nor_clear_sr_bp;
>
> /* Parse the Serial Flash Discoverable Parameters table. */
> ret = spi_nor_init_params(nor);
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 17787238f0e9..399ac34a529d 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -480,6 +480,7 @@ struct spi_nor;
> * @page_programs: page program capabilities ordered by priority: the
> * higher index in the array, the higher priority.
> * @quad_enable: enables SPI NOR quad mode.
> + * @disable_block_protection: disables block protection during power-up.
> */
> struct spi_nor_flash_parameter {
> u64 size;
> @@ -490,6 +491,7 @@ struct spi_nor_flash_parameter {
> struct spi_nor_pp_command page_programs[SNOR_CMD_PP_MAX];
>
> int (*quad_enable)(struct spi_nor *nor);
> + int (*disable_block_protection)(struct spi_nor *nor);
> };
>
> /**
> @@ -535,8 +537,6 @@ struct flash_info;
> * @flash_unlock: [FLASH-SPECIFIC] unlock a region of the SPI NOR
> * @flash_is_locked: [FLASH-SPECIFIC] check if a region of the SPI NOR is
> * completely locked
> - * @clear_sr_bp: [FLASH-SPECIFIC] clears the Block Protection Bits from
> - * the SPI NOR Status Register.
> * @params: [FLASH-SPECIFIC] SPI-NOR flash parameters and settings.
> * The structure includes legacy flash parameters and
> * settings that can be overwritten by the spi_nor_fixups
> @@ -578,7 +578,6 @@ struct spi_nor {
> int (*flash_lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
> int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
> int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
> - int (*clear_sr_bp)(struct spi_nor *nor);
> struct spi_nor_flash_parameter params;
>
> void *priv;