linux-kernel - [PATCH] mmc: core: Disable card detect during shutdown

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Date:   Fri,  3 Dec 2021 15:15:54 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     linux-mmc@...r.kernel.org, Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Al Cooper <alcooperx@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: [PATCH] mmc: core: Disable card detect during shutdown

It's seems prone to problems by allowing card detect and its corresponding
mmc_rescan() work to run, during platform shutdown. For example, we may end
up turning off the power while initializing a card, which potentially could
damage it.

To avoid this scenario, let's add ->shutdown_pre() callback for the mmc host
class device and then turn of the card detect from there.

Signed-off-by: Al Cooper <alcooperx@...il.com>
Cc: stable@...r.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 drivers/mmc/core/core.c | 7 ++++++-
 drivers/mmc/core/core.h | 1 +
 drivers/mmc/core/host.c | 9 +++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 240c5af793dc..368f10405e13 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2264,7 +2264,7 @@ void mmc_start_host(struct mmc_host *host)
 	_mmc_detect_change(host, 0, false);
 }
 
-void mmc_stop_host(struct mmc_host *host)
+void __mmc_stop_host(struct mmc_host *host)
 {
 	if (host->slot.cd_irq >= 0) {
 		mmc_gpio_set_cd_wake(host, false);
@@ -2273,6 +2273,11 @@ void mmc_stop_host(struct mmc_host *host)
 
 	host->rescan_disable = 1;
 	cancel_delayed_work_sync(&host->detect);
+}
+
+void mmc_stop_host(struct mmc_host *host)
+{
+	__mmc_stop_host(host);
 
 	/* clear pm flags now and let card drivers set them as needed */
 	host->pm_flags = 0;
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 7931a4f0137d..f5f3f623ea49 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -70,6 +70,7 @@ static inline void mmc_delay(unsigned int ms)
 
 void mmc_rescan(struct work_struct *work);
 void mmc_start_host(struct mmc_host *host);
+void __mmc_stop_host(struct mmc_host *host);
 void mmc_stop_host(struct mmc_host *host);
 
 void _mmc_detect_change(struct mmc_host *host, unsigned long delay,
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index d4683b1d263f..cf140f4ec864 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -80,9 +80,18 @@ static void mmc_host_classdev_release(struct device *dev)
 	kfree(host);
 }
 
+static int mmc_host_classdev_shutdown(struct device *dev)
+{
+	struct mmc_host *host = cls_dev_to_mmc_host(dev);
+
+	__mmc_stop_host(host);
+	return 0;
+}
+
 static struct class mmc_host_class = {
 	.name		= "mmc_host",
 	.dev_release	= mmc_host_classdev_release,
+	.shutdown_pre	= mmc_host_classdev_shutdown,
 	.pm		= MMC_HOST_CLASS_DEV_PM_OPS,
 };
 
-- 
2.25.1