[PATCH 1/2] mmc: Introduce mmc_send_stop_transmission()

[Marek Vasut]

From: Hai Pham <hai.pham.ud at renesas.com>

If a tuning command times out, the card could still be processing it,
which will cause problems for recovery. The eMMC specification section
6.6 Data transfer mode (cont’d) claims that CMD12 can be used to stop
CMD21:
"
The relationship between the various data transfer modes is summarized (see Figure 27):
- All data read commands can be aborted any time by the stop command (CMD12).
  The data transfer will terminate and the Device will return to the Transfer State.
  The read commands are: ... send tuning block (CMD21) ....
"
Add a function that does that.

Based on Linux commit [1] and [2].

[1] e711f0309109 ("mmc: mmc: Introduce mmc_abort_tuning()")
[2] 21adc2e45f4e ("mmc: Improve function name when aborting a tuning
cmd")

Reviewed-by: Takeshi Kihara <takeshi.kihara.df at renesas.com>
Reviewed-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
Signed-off-by: Hai Pham <hai.pham.ud at renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
[Marek: Update commit message, quote relevant part of the specification.
        Rename to mmc_send_stop_transmission().
	Remove tuning opcode check, this is controller driver specific.
	Deduplicate part of mmc_read_blocks() using this function.]
---
Cc: "Ying-Chun Liu (PaulLiu)" <paul.liu at linaro.org>
Cc: Hai Pham <hai.pham.ud at renesas.com>
Cc: Jaehoon Chung <jh80.chung at samsung.com>
Cc: Loic Poulain <loic.poulain at linaro.org>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Simon Glass <sjg at chromium.org>
Cc: Takeshi Kihara <takeshi.kihara.df at renesas.com>
---
 drivers/mmc/mmc.c | 16 ++++++++++++----
 include/mmc.h     |  2 ++
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 1af6af82e6b..68a76aa3e94 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -398,6 +398,17 @@ int mmc_send_tuning(struct mmc *mmc, u32 opcode, int *cmd_error)
 }
 #endif
 
+int mmc_send_stop_transmission(struct mmc *mmc)
+{
+	struct mmc_cmd cmd;
+
+	cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
+	cmd.cmdarg = 0;
+	cmd.resp_type = MMC_RSP_R1;
+
+	return mmc_send_cmd(mmc, &cmd, NULL);
+}
+
 static int mmc_read_blocks(struct mmc *mmc, void *dst, lbaint_t start,
 			   lbaint_t blkcnt)
 {
@@ -425,10 +436,7 @@ static int mmc_read_blocks(struct mmc *mmc, void *dst, lbaint_t start,
 		return 0;
 
 	if (blkcnt > 1) {
-		cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
-		cmd.cmdarg = 0;
-		cmd.resp_type = MMC_RSP_R1b;
-		if (mmc_send_cmd(mmc, &cmd, NULL)) {
+		if (mmc_send_stop_transmission(mmc)) {
 #if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_LIBCOMMON_SUPPORT)
 			pr_err("mmc fail to send stop cmd\n");
 #endif
diff --git a/include/mmc.h b/include/mmc.h
index b8fbff150de..a413dc2af4d 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -558,6 +558,8 @@ int mmc_deferred_probe(struct mmc *mmc);
 int mmc_reinit(struct mmc *mmc);
 int mmc_get_b_max(struct mmc *mmc, void *dst, lbaint_t blkcnt);
 int mmc_hs400_prepare_ddr(struct mmc *mmc);
+int mmc_send_stop_transmission(struct mmc *mmc);
+
 #else
 struct mmc_ops {
 	int (*send_cmd)(struct mmc *mmc,
-- 
2.39.2