mmc: core: Add cache control for eMMC4.5 device
This patch adds cache feature of eMMC4.5 Spec.
If device supports cache capability, host can utilize some specific
operations.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 7939015..de5900a 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -470,6 +470,12 @@
} else
card->ext_csd.generic_cmd6_time = 0;
+ card->ext_csd.cache_size =
+ ext_csd[EXT_CSD_CACHE_SIZE + 0] << 0 |
+ ext_csd[EXT_CSD_CACHE_SIZE + 1] << 8 |
+ ext_csd[EXT_CSD_CACHE_SIZE + 2] << 16 |
+ ext_csd[EXT_CSD_CACHE_SIZE + 3] << 24;
+
out:
return err;
}
@@ -1020,6 +1026,23 @@
}
}
+ /*
+ * If cache size is higher than 0, this indicates
+ * the existence of cache and it can be turned on.
+ */
+ if ((host->caps2 & MMC_CAP2_CACHE_CTRL) &&
+ card->ext_csd.cache_size > 0) {
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_CACHE_CTRL, 1, 0);
+ if (err && err != -EBADMSG)
+ goto free_card;
+
+ /*
+ * Only if no error, cache is turned on successfully.
+ */
+ card->ext_csd.cache_ctrl = err ? 0 : 1;
+ }
+
if (!oldcard)
host->card = card;