linux-kernel - [PATCH] mmc: add quirk to disable eMMC cache for Micron eMMC v5.0 cards

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Message-Id: <20210408175951.22450-1-scott.branden@broadcom.com>
Date:   Thu,  8 Apr 2021 10:59:51 -0700
From:   Scott Branden <scott.branden@...adcom.com>
To:     BCM Kernel Feedback <bcm-kernel-feedback-list@...adcom.com>,
        Ulf Hansson <ulf.hansson@...aro.org>, linux-mmc@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Vladimir Olovyannikov <vladimir.olovyannikov@...adcom.com>,
        Scott Branden <scott.branden@...adcom.com>
Subject: [PATCH] mmc: add quirk to disable eMMC cache for Micron eMMC v5.0 cards

From: Vladimir Olovyannikov <vladimir.olovyannikov@...adcom.com>

In certain rare combination of operations, Micron eMMC v5.0 cards
may experience data errors if internal cache is enabled.
This may lead to eMMC related data errors.
Introduce a quirk to disable cache on these eMMC cards.

Signed-off-by: Vladimir Olovyannikov <vladimir.olovyannikov@...adcom.com>
Signed-off-by: Scott Branden <scott.branden@...adcom.com>
---
 drivers/mmc/core/card.h   | 5 +++++
 drivers/mmc/core/mmc.c    | 4 ++--
 drivers/mmc/core/quirks.h | 8 ++++++++
 include/linux/mmc/card.h  | 1 +
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/card.h b/drivers/mmc/core/card.h
index 7bd392d55cfa..22cea63ac359 100644
--- a/drivers/mmc/core/card.h
+++ b/drivers/mmc/core/card.h
@@ -222,4 +222,9 @@ static inline int mmc_card_broken_hpi(const struct mmc_card *c)
 	return c->quirks & MMC_QUIRK_BROKEN_HPI;
 }
 
+static inline int mmc_card_broken_cache(const struct mmc_card *c)
+{
+	return c->quirks & MMC_QUIRK_BROKEN_CACHE;
+}
+
 #endif
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 8741271d3971..cd83b7f0e59c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1820,12 +1820,12 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	 * sudden power failure tests. Let's extend the timeout to a minimum of
 	 * DEFAULT_CACHE_EN_TIMEOUT_MS and do it for all cards.
 	 */
-	if (card->ext_csd.cache_size > 0) {
+	if (!mmc_card_broken_cache(card) && card->ext_csd.cache_size > 0) {
 		unsigned int timeout_ms = MIN_CACHE_EN_TIMEOUT_MS;
 
 		timeout_ms = max(card->ext_csd.generic_cmd6_time, timeout_ms);
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-				EXT_CSD_CACHE_CTRL, 1, timeout_ms);
+				 EXT_CSD_CACHE_CTRL, 1, timeout_ms);
 		if (err && err != -EBADMSG)
 			goto free_card;
 
diff --git a/drivers/mmc/core/quirks.h b/drivers/mmc/core/quirks.h
index d68e6e513a4f..23972d87c82a 100644
--- a/drivers/mmc/core/quirks.h
+++ b/drivers/mmc/core/quirks.h
@@ -116,6 +116,14 @@ static const struct mmc_fixup __maybe_unused mmc_ext_csd_fixups[] = {
 	MMC_FIXUP_EXT_CSD_REV(CID_NAME_ANY, CID_MANFID_NUMONYX,
 			      0x014e, add_quirk, MMC_QUIRK_BROKEN_HPI, 6),
 
+	/*
+	 * In certain rare combination of operations, Micron eMMC v5.0 cards
+	 * may experience data errors if internal cache is enabled.
+	 * Disabling cache for these cards eliminates the issue.
+	 */
+	MMC_FIXUP_EXT_CSD_REV(CID_NAME_ANY, CID_MANFID_MICRON,
+			      0x014e, add_quirk, MMC_QUIRK_BROKEN_CACHE, 7),
+
 	END_FIXUP
 };
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index f9ad35dd6012..22f256a4e54e 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -270,6 +270,7 @@ struct mmc_card {
 #define MMC_QUIRK_BROKEN_IRQ_POLLING	(1<<11)	/* Polling SDIO_CCCR_INTx could create a fake interrupt */
 #define MMC_QUIRK_TRIM_BROKEN	(1<<12)		/* Skip trim */
 #define MMC_QUIRK_BROKEN_HPI	(1<<13)		/* Disable broken HPI support */
+#define MMC_QUIRK_BROKEN_CACHE	(1<<14)		/* Disable broken cache */
 
 	bool			reenable_cmdq;	/* Re-enable Command Queue */
 
-- 
2.17.1