[RESEND PATCH v3 05/20] mtd: spi-nor: Add default_init() hook to tweak flash parameters

From: Tudor.Ambarus
Date: Mon Aug 26 2019 - 08:08:45 EST

From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>

As of now, the flash parameters initialization logic is as following:

a/ default flash parameters init in spi_nor_init_params()
b/ manufacturer specific flash parameters updates, split across entire
spi-nor core code
c/ flash parameters updates based on SFDP tables
d/ post BFPT flash parameter updates

In the quest of removing the manufacturer specific code from the spi-nor
core, we want to impose a timeline/priority on how the flash parameters
are updated. The following sequence of calls is pursued:

1/ spi-nor core parameters init based on 'flash_info' struct:

which can be overwritten by:
2/ MFR-based manufacturer flash parameters init:

which can be overwritten by:
3/ specific flash_info tweeks done when decisions can not be done just on

which can be overwritten by:
4/ SFDP tables flash parameters init - SFDP knows better:

which can be overwritten by:
5/ post SFDP tables flash parameters updates - in case manufacturers get
the serial flash tables wrong or incomplete.
The later can be extended to nor->manufacturer->fixups->post_sfdp() if

This patch opens doors for steps 2/ and 3/.

Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
v3: reword description

drivers/mtd/spi-nor/spi-nor.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 9dd6cd8cd13c..8fd60e1eebd2 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -154,12 +154,16 @@ struct sfdp_bfpt {

* struct spi_nor_fixups - SPI NOR fixup hooks
+ * @default_init: called after default flash parameters init. Used to tweak
+ * flash parameters when information provided by the flash_info
+ * table is incomplete or wrong.
* @post_bfpt: called after the BFPT table has been parsed
* Those hooks can be used to tweak the SPI NOR configuration when the SFDP
* table is broken or not available.
struct spi_nor_fixups {
+ void (*default_init)(struct spi_nor *nor);
int (*post_bfpt)(struct spi_nor *nor,
const struct sfdp_parameter_header *bfpt_header,
const struct sfdp_bfpt *bfpt,
@@ -4133,6 +4137,17 @@ static int spi_nor_parse_sfdp(struct spi_nor *nor,
return err;

+ * spi_nor_manufacturer_init_params() - Initialize the flash's parameters and
+ * settings based on ->default_init() hook.
+ * @nor: pointer to a 'struct spi-nor'.
+ */
+static void spi_nor_manufacturer_init_params(struct spi_nor *nor)
+ if (nor->info->fixups && nor->info->fixups->default_init)
+ nor->info->fixups->default_init(nor);
static int spi_nor_init_params(struct spi_nor *nor)
struct spi_nor_flash_parameter *params = &nor->params;
@@ -4233,6 +4248,8 @@ static int spi_nor_init_params(struct spi_nor *nor)
params->quad_enable = info->quad_enable;

+ spi_nor_manufacturer_init_params(nor);
if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
!(info->flags & SPI_NOR_SKIP_SFDP)) {
struct spi_nor_flash_parameter sfdp_params;