From 4a897cf6aa31fbb9e81dab20ac5f73515499b89d Mon Sep 17 00:00:00 2001
From: Talel Shenhar <tatias@codeaurora.org>
Date: Wed, 4 Feb 2015 17:59:23 +0200
Subject: [PATCH] mmc: quirks: add new quirk that allows Cache disable

This change allows us to prevent cache enable for certain
cards that have broken cache functionality.

Change-Id: Iea3f8c8f4e5498a8742fa408a19e3e169d1fa8cb
Signed-off-by: Talel Shenhar <tatias@codeaurora.org>
[subhashj@codeaurora.org: fixed trivial merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
---
 drivers/mmc/core/core.c  |  3 ++-
 drivers/mmc/core/mmc.c   | 54 +++++++++++++++++++++++++++-------------
 include/linux/mmc/card.h |  1 +
 3 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index b0aacd2f78d8..23ee6dc61e09 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -3354,7 +3354,8 @@ int mmc_flush_cache(struct mmc_card *card)
 
 	if (mmc_card_mmc(card) &&
 			(card->ext_csd.cache_size > 0) &&
-			(card->ext_csd.cache_ctrl & 1)) {
+			(card->ext_csd.cache_ctrl & 1) &&
+			(!(card->quirks & MMC_QUIRK_CACHE_DISABLE))) {
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				EXT_CSD_FLUSH_CACHE, 1, 0);
 		if (err == -ETIMEDOUT) {
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 245cd173eb45..c0faf2bbc711 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1816,26 +1816,46 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	 * the existence of cache and it can be turned on.
 	 * If HPI is not supported then cache shouldn't be enabled.
 	 */
-	if (card->ext_csd.cache_size > 0 && card->ext_csd.hpi_en) {
-		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-				EXT_CSD_CACHE_CTRL, 1,
-				card->ext_csd.generic_cmd6_time);
-		if (err && err != -EBADMSG) {
-			pr_err("%s: %s: mmc_switch() for CACHE_CTRL fails %d\n",
+	if (card->ext_csd.cache_size > 0) {
+		if (card->ext_csd.hpi_en &&
+			(!(card->quirks & MMC_QUIRK_CACHE_DISABLE))) {
+			err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+					EXT_CSD_CACHE_CTRL, 1,
+					card->ext_csd.generic_cmd6_time);
+			if (err && err != -EBADMSG) {
+				pr_err("%s: %s: fail on CACHE_CTRL ON %d\n",
 					mmc_hostname(host), __func__, err);
-			goto free_card;
-		}
+				goto free_card;
+			}
 
-		/*
-		 * Only if no error, cache is turned on successfully.
-		 */
-		if (err) {
-			pr_warn("%s: Cache is supported, but failed to turn on (%d)\n",
-				mmc_hostname(card->host), err);
-			card->ext_csd.cache_ctrl = 0;
-			err = 0;
+			/*
+			 * Only if no error, cache is turned on successfully.
+			 */
+			if (err) {
+				pr_warn("%s: Cache is supported, but failed to turn on (%d)\n",
+					mmc_hostname(card->host), err);
+				card->ext_csd.cache_ctrl = 0;
+				err = 0;
+			} else {
+				card->ext_csd.cache_ctrl = 1;
+			}
 		} else {
-			card->ext_csd.cache_ctrl = 1;
+			/*
+			 * mmc standard doesn't say what is the card default
+			 * value for EXT_CSD_CACHE_CTRL.
+			 * Hence, cache may be enabled by default by
+			 * card vendors.
+			 * Thus, it is best to explicitly disable cache in case
+			 * we want to avoid cache.
+			 */
+			err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+					EXT_CSD_CACHE_CTRL, 0,
+					card->ext_csd.generic_cmd6_time);
+			if (err) {
+				pr_err("%s: %s: fail on CACHE_CTRL OFF %d\n",
+					mmc_hostname(host), __func__, err);
+				goto free_card;
+			}
 		}
 	}
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4cab91c56616..c3e6fbfbcfab 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -308,6 +308,7 @@ struct mmc_card {
 #define MMC_QUIRK_INAND_DATA_TIMEOUT  (1<<13)   /* For incorrect data timeout */
 #define MMC_QUIRK_BROKEN_HPI (1 << 14)		/* For devices which gets */
 						/* broken due to HPI feature */
+#define MMC_QUIRK_CACHE_DISABLE (1 << 14)	/* prevent cache enable */
 
 
 	unsigned int		erase_size;	/* erase size in sectors */