sf: Make 4K sector support configurable

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@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>
This commit is contained in:
Marek Vasut 2015-08-03 01:28:56 +02:00 committed by Jagan Teki
parent 632093b566
commit 0a02655481
2 changed files with 19 additions and 0 deletions

View file

@ -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

View file

@ -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,