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>
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 @@
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