mmc: core: Use MMC_UNSAFE_RESUME as default behavior

Invoking system suspend or shutdown without using the Kconfig option
MMC_UNSAFE_RESUME, did trigger an ungraceful power cut of the card.

To improve the situation, change the behavior to always make use of the
available bus_ops callbacks that handles system suspend and shutdown
properly.

By changing the behavior MMC_UNSAFE_RESUME becomes redundant, so lets's
remove it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

5 files changed, 3 insertions, 80 deletions

diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
index 269d072ef55e..9ebee72d9c3f 100644
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -2,21 +2,6 @@
 # MMC core configuration
 #
 
-config MMC_UNSAFE_RESUME
-        bool "Assume MMC/SD cards are non-removable (DANGEROUS)"
-        help
-          If you say Y here, the MMC layer will assume that all cards
-          stayed in their respective slots during the suspend. The
-          normal behaviour is to remove them at suspend and
-          redetecting them at resume. Breaking this assumption will
-          in most cases result in data corruption.
-
-          This option is usually just for embedded systems which use
-          a MMC/SD card for rootfs. Most people should say N here.
-
-          This option sets a default which can be overridden by the
-          module parameter "removable=0" or "removable=1".
-
 config MMC_CLKGATE
         bool "MMC host clock gating"
         help
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 098374b1ab2b..10856ec64412 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -65,23 +65,6 @@ bool use_spi_crc = 1;
 module_param(use_spi_crc, bool, 0);
 
 /*
- * We normally treat cards as removed during suspend if they are not
- * known to be on a non-removable bus, to avoid the risk of writing
- * back data to a different card after resume.  Allow this to be
- * overridden if necessary.
- */
-#ifdef CONFIG_MMC_UNSAFE_RESUME
-bool mmc_assume_removable;
-#else
-bool mmc_assume_removable = 1;
-#endif
-EXPORT_SYMBOL(mmc_assume_removable);
-module_param_named(removable, mmc_assume_removable, bool, 0644);
-MODULE_PARM_DESC(
-        removable,
-        "MMC/SD cards are removable and may be removed during suspend");
-
-/*
  * Internal function. Schedule delayed work in the MMC work queue.
  */
 static int mmc_schedule_delayed_work(struct delayed_work *work,
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 98e9eb0f6643..20f046895228 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1636,16 +1636,6 @@ static int mmc_power_restore(struct mmc_host *host)
 static const struct mmc_bus_ops mmc_ops = {
         .remove = mmc_remove,
         .detect = mmc_detect,
-        .suspend = NULL,
-        .resume = NULL,
-        .power_restore = mmc_power_restore,
-        .alive = mmc_alive,
-        .shutdown = mmc_shutdown,
-};
-
-static const struct mmc_bus_ops mmc_ops_unsafe = {
-        .remove = mmc_remove,
-        .detect = mmc_detect,
         .suspend = mmc_suspend,
         .resume = mmc_resume,
         .runtime_suspend = mmc_runtime_suspend,
@@ -1655,17 +1645,6 @@ static const struct mmc_bus_ops mmc_ops_unsafe = {
         .shutdown = mmc_shutdown,
 };
 
-static void mmc_attach_bus_ops(struct mmc_host *host)
-{
-        const struct mmc_bus_ops *bus_ops;
-
-        if (!mmc_card_is_removable(host))
-                bus_ops = &mmc_ops_unsafe;
-        else
-                bus_ops = &mmc_ops;
-        mmc_attach_bus(host, bus_ops);
-}
-
 /*
  * Starting point for MMC card init.
  */
@@ -1685,7 +1664,7 @@ int mmc_attach_mmc(struct mmc_host *host)
         if (err)
                 return err;
 
-        mmc_attach_bus_ops(host);
+        mmc_attach_bus(host, &mmc_ops);
         if (host->ocr_avail_mmc)
                 host->ocr_avail = host->ocr_avail_mmc;
 
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 692fdb177294..2dd359d2242f 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1209,16 +1209,6 @@ static int mmc_sd_power_restore(struct mmc_host *host)
 static const struct mmc_bus_ops mmc_sd_ops = {
         .remove = mmc_sd_remove,
         .detect = mmc_sd_detect,
-        .suspend = NULL,
-        .resume = NULL,
-        .power_restore = mmc_sd_power_restore,
-        .alive = mmc_sd_alive,
-        .shutdown = mmc_sd_suspend,
-};
-
-static const struct mmc_bus_ops mmc_sd_ops_unsafe = {
-        .remove = mmc_sd_remove,
-        .detect = mmc_sd_detect,
         .runtime_suspend = mmc_sd_runtime_suspend,
         .runtime_resume = mmc_sd_runtime_resume,
         .suspend = mmc_sd_suspend,
@@ -1228,17 +1218,6 @@ static const struct mmc_bus_ops mmc_sd_ops_unsafe = {
         .shutdown = mmc_sd_suspend,
 };
 
-static void mmc_sd_attach_bus_ops(struct mmc_host *host)
-{
-        const struct mmc_bus_ops *bus_ops;
-
-        if (!mmc_card_is_removable(host))
-                bus_ops = &mmc_sd_ops_unsafe;
-        else
-                bus_ops = &mmc_sd_ops;
-        mmc_attach_bus(host, bus_ops);
-}
-
 /*
  * Starting point for SD card init.
  */
@@ -1254,7 +1233,7 @@ int mmc_attach_sd(struct mmc_host *host)
         if (err)
                 return err;
 
-        mmc_sd_attach_bus_ops(host);
+        mmc_attach_bus(host, &mmc_sd_ops);
         if (host->ocr_avail_sd)
                 host->ocr_avail = host->ocr_avail_sd;
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 99f5709ac343..2a139b2bdb9e 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -424,12 +424,9 @@ static inline int mmc_regulator_get_supply(struct mmc_host *mmc)
 
 int mmc_pm_notify(struct notifier_block *notify_block, unsigned long, void *);
 
-/* Module parameter */
-extern bool mmc_assume_removable;
-
 static inline int mmc_card_is_removable(struct mmc_host *host)
 {
-        return !(host->caps & MMC_CAP_NONREMOVABLE) && mmc_assume_removable;
+        return !(host->caps & MMC_CAP_NONREMOVABLE);
 }
 
 static inline int mmc_card_keep_power(struct mmc_host *host)