linux-kernel - [PATCH 4.19 09/48] mmc: core: Allow host controllers to require R1B for CMD6

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Date:   Thu, 19 Mar 2020 14:03:51 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Sowjanya Komatineni <skomatineni@...dia.com>,
        Anders Roxell <anders.roxell@...aro.org>,
        Faiz Abbas <faiz_abbas@...com>,
        Peter Geis <pgwipeout@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 09/48] mmc: core: Allow host controllers to require R1B for CMD6

From: Ulf Hansson <ulf.hansson@...aro.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@...dia.com>
Cc: <stable@...r.kernel.org>
Tested-by: Anders Roxell <anders.roxell@...aro.org>
Tested-by: Sowjanya Komatineni <skomatineni@...dia.com>
Tested-by: Faiz Abbas <faiz_abbas@...com>
Tested-By: Peter Geis <pgwipeout@...il.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/mmc/core/mmc_ops.c | 6 ++++--
 include/linux/mmc/host.h   | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 76de8d441cce4..9ae41fbe009bd 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -538,9 +538,11 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 	 * If the max_busy_timeout of the host is specified, make sure it's
 	 * enough to fit the used timeout_ms. In case it's not, let's instruct
 	 * the host to avoid HW busy detection, by converting to a R1 response
-	 * instead of a R1B.
+	 * 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 (host->max_busy_timeout && (timeout_ms > host->max_busy_timeout))
+	if (!(host->caps & MMC_CAP_NEED_RSP_BUSY) && 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 840462ed1ec7e..7e8e5b20e82b0 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -332,6 +332,7 @@ struct mmc_host {
 				 MMC_CAP_UHS_SDR50 | MMC_CAP_UHS_SDR104 | \
 				 MMC_CAP_UHS_DDR50)
 /* (1 << 21) is free for reuse */
+#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