spl: fat: Add option to disable DMA alignment
If we don't DMA-align buffers we pass to FAT, it will align them itself.
This behaviour likely should be deprecated in favor of
CONFIG_BOUNCE_BUFFER, but that's a task for another series. For the
meantime, don't bother aligning the buffer unless we had been doing so in
the past.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index b935269..fc284a5 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -694,13 +694,28 @@
config SPL_FS_FAT
bool "Support FAT filesystems"
select FS_FAT
- select SPL_LOAD_BLOCK
help
Enable support for FAT and VFAT filesystems with SPL. This
permits U-Boot (or Linux in Falcon mode) to be loaded from a FAT
filesystem from within SPL. Support for the underlying block
device (e.g. MMC or USB) must be enabled separately.
+config SPL_FS_FAT_DMA_ALIGN
+ bool "Use DMA-aligned buffers with FAT"
+ depends on SPL_FS_FAT
+ select SPL_LOAD_BLOCK
+ default y if SPL_LOAD_FIT
+ help
+ The FAT filesystem driver tries to ensure that the reads it issues to
+ the block subsystem use DMA-aligned buffers. If the supplied buffer is
+ not DMA-aligned, the FAT driver will use a bounce-buffer and read
+ block-by-block. This is separate from the bounce-buffer used by the
+ block subsystem (CONFIG_BOUNCE_BUFFER).
+
+ Enable this config to align buffers passed to the FAT filesystem
+ driver. This will speed up reads, but will increase the size of U-Boot
+ by around 60 bytes.
+
config SPL_FS_LOAD_PAYLOAD_NAME
string "File to load for U-Boot from the filesystem"
depends on SPL_FS_EXT4 || SPL_FS_FAT || SPL_FS_SQUASHFS || SPL_SEMIHOSTING
@@ -1282,7 +1297,6 @@
depends on BLK
select FS_LOADER
select SPL_BLK_FS
- select SPL_LOAD_BLOCK
help
This option enables support for NVM Express devices.
It supports basic functions of NVMe (read/write).