mmc: MMC-4.5 Data Tag Support

MMC-4.5 data tag feature will be used to store the file system meta-data
in the tagged region of eMMC. This will improve the write and subsequent
read transfer time for the meta data.

Signed-off-by: Saugata Das <saugata.das@linaro.org>
Tested-by: Venkatraman S <svenkatr@ti.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 2b9ed1401dc4..6defddd795f6 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -519,6 +519,20 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
                         ext_csd[EXT_CSD_CACHE_SIZE + 1] << 8 |
                         ext_csd[EXT_CSD_CACHE_SIZE + 2] << 16 |
                         ext_csd[EXT_CSD_CACHE_SIZE + 3] << 24;
+
+                if (ext_csd[EXT_CSD_DATA_SECTOR_SIZE] == 1)
+                        card->ext_csd.data_sector_size = 4096;
+                else
+                        card->ext_csd.data_sector_size = 512;
+
+                if ((ext_csd[EXT_CSD_DATA_TAG_SUPPORT] & 1) &&
+                    (ext_csd[EXT_CSD_TAG_UNIT_SIZE] <= 8)) {
+                        card->ext_csd.data_tag_unit_size =
+                        ((unsigned int) 1 << ext_csd[EXT_CSD_TAG_UNIT_SIZE]) *
+                        (card->ext_csd.data_sector_size);
+                } else {
+                        card->ext_csd.data_tag_unit_size = 0;
+                }
         }
 
 out: