diff mbox series

[v2,01/35] mtd: spi-nor: core: Introduce SPI_NOR_PARSE_SFDP

Message ID 20210727045222.905056-2-tudor.ambarus@microchip.com (mailing list archive)
State New, archived
Headers show
Series mtd: spi-nor: Handle ID collisions and clean params init | expand

Commit Message

Tudor Ambarus July 27, 2021, 4:51 a.m. UTC
SPI NOR flashes that statically declare one of the
SPI_NOR_{DUAL, QUAD, OCTAL, OCTAL_DTR}_READ flags and do not support
the RDSFDP command are gratuiously receiving the RDSFDP command
in the attempt of parsing the SFDP tables. It is not desirable to issue
commands that are not supported, so introduce a flag to help on this
situation.

New flash additions that support the SFDP standard should be declared
using SPI_NOR_PARSE_SFDP. Support that can be discovered when parsing
SFDP should not be duplicated by explicit flags at flash declaration.
All the flash parameters will be discovered when parsing SFDP.
Sometimes manufacturers wrongly define some fields in the SFDP tables.
If that's the case, SFDP data can be amended with the fixups() hooks.
It is not common, but if the SFDP tables are entirely wrong, and it
does not worth the hassle to tweak the SFDP parameters by using the
fixups hooks, or if the flash does not define the SFDP tables at all,
then statically init the flash with the SPI_NOR_SKIP_SFDP flag and
specify the rest of flash capabilities with the flash info flags.

With time, we want to convert all flashes to SPI_NOR_PARSE_SFDP and
stop triggering the SFDP parsing with the
SPI_NOR_{DUAL, QUAD, OCTAL*}_READ flags. Getting rid of the
SPI_NOR_{OCTAL, OCTAL_DTR}_READ trigger is easily achievable, the rest
are a long term goal.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Heiko Thiery <heiko.thiery@gmail.com>
---
 drivers/mtd/spi-nor/core.c | 3 ++-
 drivers/mtd/spi-nor/core.h | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

Comments

Pratyush Yadav Aug. 4, 2021, 8:09 a.m. UTC | #1
On 27/07/21 07:51AM, Tudor Ambarus wrote:
> SPI NOR flashes that statically declare one of the
> SPI_NOR_{DUAL, QUAD, OCTAL, OCTAL_DTR}_READ flags and do not support
> the RDSFDP command are gratuiously receiving the RDSFDP command
> in the attempt of parsing the SFDP tables. It is not desirable to issue
> commands that are not supported, so introduce a flag to help on this
> situation.
> 
> New flash additions that support the SFDP standard should be declared
> using SPI_NOR_PARSE_SFDP. Support that can be discovered when parsing
> SFDP should not be duplicated by explicit flags at flash declaration.
> All the flash parameters will be discovered when parsing SFDP.
> Sometimes manufacturers wrongly define some fields in the SFDP tables.
> If that's the case, SFDP data can be amended with the fixups() hooks.
> It is not common, but if the SFDP tables are entirely wrong, and it
> does not worth the hassle to tweak the SFDP parameters by using the
> fixups hooks, or if the flash does not define the SFDP tables at all,
> then statically init the flash with the SPI_NOR_SKIP_SFDP flag and
> specify the rest of flash capabilities with the flash info flags.
> 
> With time, we want to convert all flashes to SPI_NOR_PARSE_SFDP and
> stop triggering the SFDP parsing with the
> SPI_NOR_{DUAL, QUAD, OCTAL*}_READ flags. Getting rid of the
> SPI_NOR_{OCTAL, OCTAL_DTR}_READ trigger is easily achievable, the rest
> are a long term goal.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> Reviewed-by: Heiko Thiery <heiko.thiery@gmail.com>

Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Michael Walle Aug. 23, 2021, 10:17 p.m. UTC | #2
Am 2021-07-27 06:51, schrieb Tudor Ambarus:
> SPI NOR flashes that statically declare one of the
> SPI_NOR_{DUAL, QUAD, OCTAL, OCTAL_DTR}_READ flags and do not support
> the RDSFDP command are gratuiously receiving the RDSFDP command
> in the attempt of parsing the SFDP tables. It is not desirable to issue
> commands that are not supported, so introduce a flag to help on this
> situation.
> 
> New flash additions that support the SFDP standard should be declared
> using SPI_NOR_PARSE_SFDP. Support that can be discovered when parsing
> SFDP should not be duplicated by explicit flags at flash declaration.
> All the flash parameters will be discovered when parsing SFDP.
> Sometimes manufacturers wrongly define some fields in the SFDP tables.
> If that's the case, SFDP data can be amended with the fixups() hooks.
> It is not common, but if the SFDP tables are entirely wrong, and it
> does not worth the hassle to tweak the SFDP parameters by using the
> fixups hooks, or if the flash does not define the SFDP tables at all,
> then statically init the flash with the SPI_NOR_SKIP_SFDP flag and
> specify the rest of flash capabilities with the flash info flags.
> 
> With time, we want to convert all flashes to SPI_NOR_PARSE_SFDP and
> stop triggering the SFDP parsing with the
> SPI_NOR_{DUAL, QUAD, OCTAL*}_READ flags. Getting rid of the
> SPI_NOR_{OCTAL, OCTAL_DTR}_READ trigger is easily achievable, the rest
> are a long term goal.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> Reviewed-by: Heiko Thiery <heiko.thiery@gmail.com>

Reviewed-by: Michael Walle <michael@walle.cc>
diff mbox series

Patch

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index cc08bd707378..3d9f3698fb7b 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2726,7 +2726,8 @@  static int spi_nor_init_params(struct spi_nor *nor)
 
 	spi_nor_manufacturer_init_params(nor);
 
-	if ((nor->info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
+	if ((nor->info->flags & (SPI_NOR_PARSE_SFDP |
+				 SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
 				 SPI_NOR_OCTAL_READ | SPI_NOR_OCTAL_DTR_READ)) &&
 	    !(nor->info->flags & SPI_NOR_SKIP_SFDP))
 		spi_nor_sfdp_init_params(nor);
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index 3348e1dd1445..55fceb0ec894 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -382,6 +382,10 @@  struct flash_info {
 					 * protection bits. Usually these will
 					 * power-up in a write-protected state.
 					 */
+#define SPI_NOR_PARSE_SFDP	BIT(23) /*
+					 * Flash initialized based on the SFDP
+					 * tables.
+					 */
 
 	const struct spi_nor_otp_organization otp_org;