Re: [PATCH 1/3] mtd: spi-nor: sst: fix write support for SST_WRITE marked devices

Vignesh Raghavendra
2020-09-14T13:57:43Z

On 9/11/20 8:17 PM, Marco Felsch wrote:
> The sst write support for devices using the special SST_WRITE routine
> is broken since commit commit df5c21002cf4 ("mtd: spi-nor: use spi-mem
> dirmap API") because the spi_nor_create_write_dirmap() function checks
> SPINOR_OP_AAI_WP and sst_write_second. These checks are not valid during
> probe. The check seems also to be broken since the "op->addr.nbytes = 0"
> causes the devm_spi_mem_dirmap_create() function to return
> PTR_ERR(-EINVAL) and the probe() function will fail.
>
> It seems that the commit only copy'n'pasted the existing logic. Use the
> correct SST_WRITE flag and return 0 to fix both issues.
>
> Fixes: df5c21002cf4 ("mtd: spi-nor: use spi-mem dirmap API")
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
> drivers/mtd/spi-nor/core.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 65eff4ce6ab1..31869ac245a8 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -3289,15 +3289,21 @@ static int spi_nor_create_write_dirmap(struct spi_nor *nor)
> };
> struct spi_mem_op *op = &info.op_tmpl;
>
> + /*
> + * Most SST SPI-NOR's have a special write routine.which should so

s/SPI-NOR/SPI NOR.

> + * dirmap.wdesc is not supported for these.

Or How about more readable version:

"Most SST flashes have special sequence for writing data to the flash
and therefore cannot support writes through direct mapping APIs."

> + */
> + if (nor->info->flags & SST_WRITE) {
> + nor->dirmap.wdesc = NULL;

nor->dirmap.wdesc is known to be NULL at this point. So no need to set
to NULL again.

> + return 0;
> + }
> +
> /* get transfer protocols. */
> op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
> op->addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
> op->dummy.buswidth = op->addr.buswidth;
> op->data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
>
> - if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
> - op->addr.nbytes = 0;
> -
> nor->dirmap.wdesc = devm_spi_mem_dirmap_create(nor->dev, nor->spimem,
> &info);
> return PTR_ERR_OR_ZERO(nor->dirmap.wdesc);
>