[U-Boot] [PATCH] sf: Make 4K sector support configurable

[Jagan Teki]

On 5 August 2015 at 13:50, Jagan Teki <jteki at openedev.com> wrote:
> On 3 August 2015 at 04:58, Marek Vasut <marex at denx.de> wrote:
>> Make the support for 4K subpage I/O on a SPI NOR flash configurable.
>> A board which requires the SPI NOR to be accessed in larger 32KiB
>> or 64KiB pages can disable the 4K subpage support, but by default,
>> the support for 4K subpage I/O is enabled. The functionality of this
>> option is the same as CONFIG_MTD_SPI_NOR_USE_4K_SECTORS in Linux.
>>
>> This is extremely useful in case one uses UBI on a SPI NOR flash.
>> UBI needs at least 15k EBs and can not work on a flash which uses
>> 4k ones, so disabling the support for 4k subpages lets UBI work on
>> such flash.
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> Cc: Jagan Teki <jteki at openedev.com>
>> ---
>>  drivers/mtd/spi/Kconfig       | 15 +++++++++++++++
>>  drivers/mtd/spi/sf_internal.h |  4 ++++
>>  2 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig
>> index 8b730ff..3f7433c 100644
>> --- a/drivers/mtd/spi/Kconfig
>> +++ b/drivers/mtd/spi/Kconfig
>> @@ -86,6 +86,21 @@ config SPI_FLASH_WINBOND
>>
>>  endif
>>
>> +config SPI_FLASH_USE_4K_SECTORS
>> +       bool "Use small 4096 B erase sectors"
>> +       depends on SPI_FLASH
>> +       default y
>> +       help
>> +         Many flash memories support erasing small (4096 B) sectors. Depending
>> +         on the usage this feature may provide performance gain in comparison
>> +         to erasing whole blocks (32/64 KiB).
>> +         Changing a small part of the flash's contents is usually faster with
>> +         small sectors. On the other hand erasing should be faster when using
>> +         64 KiB block instead of 16 × 4 KiB sectors.
>> +
>> +         Please note that some tools/drivers/filesystems may not work with
>> +         4096 B erase size (e.g. UBIFS requires 15 KiB as a minimum).
>> +
>>  config SPI_FLASH_DATAFLASH
>>         bool "AT45xxx DataFlash support"
>>         depends on SPI_FLASH && DM_SPI_FLASH
>> diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
>> index 9fb5557..9c95d56 100644
>> --- a/drivers/mtd/spi/sf_internal.h
>> +++ b/drivers/mtd/spi/sf_internal.h
>> @@ -37,7 +37,11 @@ enum spi_read_cmds {
>>
>>  /* sf param flags */
>>  enum {
>> +#ifdef CONFIG_SPI_FLASH_USE_4K_SECTORS
>>         SECT_4K         = 1 << 0,
>> +#else
>> +       SECT_4K         = 0 << 0,
>> +#endif
>>         SECT_32K        = 1 << 1,
>>         E_FSR           = 1 << 2,
>>         SST_BP          = 1 << 3,
>> --
>> 2.1.4
>
> Reviewed-by: Jagan Teki <jteki at openedev.com>

Applied to u-boot-spi/master

thanks!
-- 
Jagan | openedev.