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 b93526904ebdaf5d5a87f5637d8892ca98266088..fc284a5bffce275c545138a7c8243ae0923aafef 100644 (file)
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -694,13 +694,28 @@ config SPL_FS_SQUASHFS
 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 @@ config SPL_NVME
        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).

diff --git a/common/spl/spl_blk_fs.c b/common/spl/spl_blk_fs.c
index ac267ab979bb8e4408fe3a35394a83ad2ffaa738..04eac6f306bdda08113d04cd220473c61149094e 100644 (file)
--- a/common/spl/spl_blk_fs.c
+++ b/common/spl/spl_blk_fs.c
@@ -82,7 +82,10 @@ int spl_blk_load_image(struct spl_image_info *spl_image,
        }
 
        load.read = spl_fit_read;
-       spl_set_bl_len(&load, ARCH_DMA_MINALIGN);
+       if (IS_ENABLED(CONFIG_SPL_FS_FAT_DMA_ALIGN))
+               spl_set_bl_len(&load, ARCH_DMA_MINALIGN);
+       else
+               spl_set_bl_len(&load, 1);
        load.priv = &dev;
        return spl_load(spl_image, bootdev, &load, filesize, 0);
 }

diff --git a/common/spl/spl_fat.c b/common/spl/spl_fat.c
index 569f2b32928699b2daa605ecc63db722c91c7939..a52f9e178e664813f0109305ab6e2bfa1ccf7631 100644 (file)
--- a/common/spl/spl_fat.c
+++ b/common/spl/spl_fat.c
@@ -86,7 +86,10 @@ int spl_load_image_fat(struct spl_image_info *spl_image,
        }
 
        load.read = spl_fit_read;
-       spl_set_bl_len(&load, ARCH_DMA_MINALIGN);
+       if (IS_ENABLED(CONFIG_SPL_FS_FAT_DMA_ALIGN))
+               spl_set_bl_len(&load, ARCH_DMA_MINALIGN);
+       else
+               spl_set_bl_len(&load, 1);
        load.priv = (void *)filename;
        err = spl_load(spl_image, bootdev, &load, size, 0);