mmc: core: Move eMMC cache flushing to a new bus_ops callback

To prepare to add internal cache management for SD cards, let's start by
moving the eMMC specific code into a new ->flush_cache() bus_ops callback.

In this way, it becomes straight forward to add the SD specific parts,
as subsequent changes are about to show.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210506145829.198823-2-ulf.hansson@linaro.org

drivers/mmc/core/block.c

@@ -1167,7 +1167,7 @@ static void mmc_blk_issue_flush(struct mmc_queue *mq, struct request *req)
 	struct mmc_card *card = md->queue.card;
 	int ret = 0;
 
-	ret = mmc_flush_cache(card);
+	ret = mmc_flush_cache(card->host);
 	blk_mq_end_request(req, ret ? BLK_STS_IOERR : BLK_STS_OK);
 }
 

drivers/mmc/core/core.h

@@ -30,6 +30,7 @@ struct mmc_bus_ops {
 	int (*hw_reset)(struct mmc_host *);
 	int (*sw_reset)(struct mmc_host *);
 	bool (*cache_enabled)(struct mmc_host *);
+	int (*flush_cache)(struct mmc_host *);
 };
 
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
@@ -172,4 +173,12 @@ static inline bool mmc_cache_enabled(struct mmc_host *host)
 	return false;
 }
 
+static inline int mmc_flush_cache(struct mmc_host *host)
+{
+	if (host->bus_ops->flush_cache)
+		return host->bus_ops->flush_cache(host);
+
+	return 0;
+}
+
 #endif

drivers/mmc/core/mmc.c

@@ -28,6 +28,7 @@
 
 #define DEFAULT_CMD6_TIMEOUT_MS	500
 #define MIN_CACHE_EN_TIMEOUT_MS 1600
+#define CACHE_FLUSH_TIMEOUT_MS 30000 /* 30s */
 
 static const unsigned int tran_exp[] = {
 	10000,		100000,		1000000,	10000000,
@@ -2036,6 +2037,25 @@ static bool _mmc_cache_enabled(struct mmc_host *host)
 	       host->card->ext_csd.cache_ctrl & 1;
 }
 
+/*
+ * Flush the internal cache of the eMMC to non-volatile storage.
+ */
+static int _mmc_flush_cache(struct mmc_host *host)
+{
+	int err = 0;
+
+	if (_mmc_cache_enabled(host)) {
+		err = mmc_switch(host->card, EXT_CSD_CMD_SET_NORMAL,
+				 EXT_CSD_FLUSH_CACHE, 1,
+				 CACHE_FLUSH_TIMEOUT_MS);
+		if (err)
+			pr_err("%s: cache flush error %d\n",
+			       mmc_hostname(host), err);
+	}
+
+	return err;
+}
+
 static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
 {
 	int err = 0;
@@ -2047,7 +2067,7 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
 	if (mmc_card_suspended(host->card))
 		goto out;
 
-	err = mmc_flush_cache(host->card);
+	err = _mmc_flush_cache(host);
 	if (err)
 		goto out;
 
@@ -2188,7 +2208,7 @@ static int _mmc_hw_reset(struct mmc_host *host)
 	 * In the case of recovery, we can't expect flushing the cache to work
 	 * always, but we have a go and ignore errors.
 	 */
-	mmc_flush_cache(host->card);
+	_mmc_flush_cache(host);
 
 	if ((host->caps & MMC_CAP_HW_RESET) && host->ops->hw_reset &&
 	     mmc_can_reset(card)) {
@@ -2216,6 +2236,7 @@ static const struct mmc_bus_ops mmc_ops = {
 	.shutdown = mmc_shutdown,
 	.hw_reset = _mmc_hw_reset,
 	.cache_enabled = _mmc_cache_enabled,
+	.flush_cache = _mmc_flush_cache,
 };
 
 /*

drivers/mmc/core/mmc_ops.c

@@ -20,7 +20,6 @@
 #include "mmc_ops.h"
 
 #define MMC_BKOPS_TIMEOUT_MS		(120 * 1000) /* 120s */
-#define MMC_CACHE_FLUSH_TIMEOUT_MS	(30 * 1000) /* 30s */
 #define MMC_SANITIZE_TIMEOUT_MS		(240 * 1000) /* 240s */
 
 static const u8 tuning_blk_pattern_4bit[] = {
@@ -964,26 +963,6 @@ void mmc_run_bkops(struct mmc_card *card)
 }
 EXPORT_SYMBOL(mmc_run_bkops);
 
-/*
- * Flush the cache to the non-volatile storage.
- */
-int mmc_flush_cache(struct mmc_card *card)
-{
-	int err = 0;
-
-	if (mmc_cache_enabled(card->host)) {
-		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
-				 EXT_CSD_FLUSH_CACHE, 1,
-				 MMC_CACHE_FLUSH_TIMEOUT_MS);
-		if (err)
-			pr_err("%s: cache flush error %d\n",
-					mmc_hostname(card->host), err);
-	}
-
-	return err;
-}
-EXPORT_SYMBOL(mmc_flush_cache);
-
 static int mmc_cmdq_switch(struct mmc_card *card, bool enable)
 {
 	u8 val = enable ? EXT_CSD_CMDQ_MODE_ENABLED : 0;

drivers/mmc/core/mmc_ops.h

@@ -51,7 +51,6 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 		unsigned int timeout_ms);
 void mmc_run_bkops(struct mmc_card *card);
-int mmc_flush_cache(struct mmc_card *card);
 int mmc_cmdq_enable(struct mmc_card *card);
 int mmc_cmdq_disable(struct mmc_card *card);
 int mmc_sanitize(struct mmc_card *card, unsigned int timeout_ms);