mmc: mmc: Add Command Queue definitions

Add definitions relating to Command Queuing.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 3268fcd..16cf6ea 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -618,6 +618,24 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
 			(ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
 			!(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
 	}
+
+	/* eMMC v5.1 or later */
+	if (card->ext_csd.rev >= 8) {
+		card->ext_csd.cmdq_support = ext_csd[EXT_CSD_CMDQ_SUPPORT] &
+					     EXT_CSD_CMDQ_SUPPORTED;
+		card->ext_csd.cmdq_depth = (ext_csd[EXT_CSD_CMDQ_DEPTH] &
+					    EXT_CSD_CMDQ_DEPTH_MASK) + 1;
+		/* Exclude inefficiently small queue depths */
+		if (card->ext_csd.cmdq_depth <= 2) {
+			card->ext_csd.cmdq_support = false;
+			card->ext_csd.cmdq_depth = 0;
+		}
+		if (card->ext_csd.cmdq_support) {
+			pr_debug("%s: Command Queue supported depth %u\n",
+				 mmc_hostname(card->host),
+				 card->ext_csd.cmdq_depth);
+		}
+	}
 out:
 	return err;
 }