[PATCH 2/2] mmc: core: Re-work HW reset for SDIO cards

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

It have turned out that it's not a good idea to try to power cycle and to
re-initialize the SDIO card, via mmc_hw_reset. This because there may be
multiple SDIO funcs attached to the same SDIO card.

To solve this problem, we would need to inform each of the SDIO func in
some way when mmc_sdio_hw_reset() gets called, but that isn't an entirely
trivial operation. Therefore, let's instead take the easy way out, by
triggering a card removal and force a new rescan of the SDIO card.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/core.c |  3 +--
 drivers/mmc/core/core.h |  2 ++
 drivers/mmc/core/sdio.c | 11 +++++++++--
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 6f8342702c73..39c4567e39d8 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1469,8 +1469,7 @@ void mmc_detach_bus(struct mmc_host *host)
 	mmc_bus_put(host);
 }
 
-static void _mmc_detect_change(struct mmc_host *host, unsigned long delay,
-				bool cd_irq)
+void _mmc_detect_change(struct mmc_host *host, unsigned long delay, bool cd_irq)
 {
 	/*
 	 * If the device is configured as wakeup, we prevent a new sleep for
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 328c78dbee66..575ac0257af2 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -70,6 +70,8 @@ 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_detect_change(struct mmc_host *host, unsigned long delay,
+			bool cd_irq);
 int _mmc_detect_card_removed(struct mmc_host *host);
 int mmc_detect_card_removed(struct mmc_host *host);
 
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 26cabd53ddc5..5d7462c223c3 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -1050,8 +1050,15 @@ static int mmc_sdio_runtime_resume(struct mmc_host *host)
 
 static int mmc_sdio_hw_reset(struct mmc_host *host)
 {
-	mmc_power_cycle(host, host->card->ocr);
-	return mmc_sdio_reinit_card(host);
+	/*
+	 * We may have more multiple SDIO funcs. Rather than to inform them all,
+	 * let's trigger a removal and force a new rescan of the card.
+	 */
+	host->rescan_entered = 0;
+	mmc_card_set_removed(host->card);
+	_mmc_detect_change(host, 0, false);
+
+	return 0;
 }
 
 static int mmc_sdio_sw_reset(struct mmc_host *host)
-- 
2.17.1