[PATCH 5.5.12 1/5] mmc: core: Allow host controllers to require R1B for CMD6

[Ulf Hansson <ulf.hansson@linaro.org>]

[ Upstream commit 1292e3efb149ee21d8d33d725eeed4e6b1ade963 ]

It has turned out that some host controllers can't use R1B for CMD6 and
other commands that have R1B associated with them. Therefore invent a new
host cap, MMC_CAP_NEED_RSP_BUSY to let them specify this.

In __mmc_switch(), let's check the flag and use it to prevent R1B responses
from being converted into R1. Note that, this also means that the host are
on its own, when it comes to manage the busy timeout.

Suggested-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Cc: <stable@vger.kernel.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Tested-by: Faiz Abbas <faiz_abbas@ti.com>
Tested-By: Peter Geis <pgwipeout@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/mmc_ops.c | 8 +++++---
 include/linux/mmc/host.h   | 1 +
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 09113b9ad679..18a7afb2a5b2 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -538,10 +538,12 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 	 * If the cmd timeout and the max_busy_timeout of the host are both
 	 * specified, let's validate them. A failure means we need to prevent
 	 * the host from doing hw busy detection, which is done by converting
-	 * to a R1 response instead of a R1B.
+	 * to a R1 response instead of a R1B. Note, some hosts requires R1B,
+	 * which also means they are on their own when it comes to deal with the
+	 * busy timeout.
 	 */
-	if (timeout_ms && host->max_busy_timeout &&
-		(timeout_ms > host->max_busy_timeout))
+	if (!(host->caps & MMC_CAP_NEED_RSP_BUSY) && timeout_ms &&
+	    host->max_busy_timeout && (timeout_ms > host->max_busy_timeout))
 		use_r1b_resp = false;
 
 	cmd.opcode = MMC_SWITCH;
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index ba703384bea0..4c5eb3aa8e72 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -333,6 +333,7 @@ struct mmc_host {
 				 MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 | \
 				 MMC_CAP_UHS_DDR50)
 #define MMC_CAP_SYNC_RUNTIME_PM	(1 << 21)	/* Synced runtime PM suspends. */
+#define MMC_CAP_NEED_RSP_BUSY	(1 << 22)	/* Commands with R1B can't use R1. */
 #define MMC_CAP_DRIVER_TYPE_A	(1 << 23)	/* Host supports Driver Type A */
 #define MMC_CAP_DRIVER_TYPE_C	(1 << 24)	/* Host supports Driver Type C */
 #define MMC_CAP_DRIVER_TYPE_D	(1 << 25)	/* Host supports Driver Type D */
-- 
2.20.1