mtd: nand/fsmc: Access the NAND device word by word whenever possible

The default way of accessing nand device is using the nand width. This means
that 8bit devices are using u8 * and 16bit devices are accessed using u16 *.

This results in a non-optimal performance since the FSMC is designed to
translate the normal word accesses into device width based accesses. This patch
implements read_buf and write_buf callbacks using word by word accesses.

Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Reviewed-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/mtd/fsmc.h b/include/linux/mtd/fsmc.h
index c4ac07a19691..1edd2b3ac38e 100644
--- a/include/linux/mtd/fsmc.h
+++ b/include/linux/mtd/fsmc.h
@@ -141,6 +141,11 @@ struct fsmc_nand_timings {
         uint8_t tset;
 };
 
+enum access_mode {
+        USE_DMA_ACCESS = 1,
+        USE_WORD_ACCESS,
+};
+
 /**
  * fsmc_nand_platform_data - platform specific NAND controller config
  * @partitions: partition table for the platform, use a default fallback
@@ -164,6 +169,7 @@ struct fsmc_nand_platform_data {
         /* CLE, ALE offsets */
         unsigned long           cle_off;
         unsigned long           ale_off;
+        enum access_mode        mode;
 
         void                    (*select_bank)(uint32_t bank, uint32_t busw);
 };