[PATCH 2/3] mmc: add MMC_QUIRK_BROKEN_CLK_GATING

[Pierre Tardy]

Some sdio card are not following sdio standard, and does not work
when the sdio bus's clock is gated

To keep functionnality for all legacy driver, we turn this quirk on
for every sdio card.
Drivers needs to disable the quirk manually when someone verified that their
supported card works with clock gating.

Signed-off-by: Pierre Tardy <tardyp@xxxxxxxxx>
---
 drivers/mmc/core/host.c   |    5 +----
 drivers/mmc/core/quirks.c |   11 +++++++++++
 include/linux/mmc/card.h  |    1 +
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index b3ac6c5..461e6a1 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -160,10 +160,7 @@ static bool mmc_host_may_gate_card(struct mmc_card *card)
 	 * gate the clock, because there is somebody out there that may still
 	 * be using it.
 	 */
-	if (mmc_card_sdio(card))
-		return false;
-
-	return true;
+	return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
 }
 
 /**
diff --git a/drivers/mmc/core/quirks.c b/drivers/mmc/core/quirks.c
index d8a5fec..fe467c8 100644
--- a/drivers/mmc/core/quirks.c
+++ b/drivers/mmc/core/quirks.c
@@ -32,7 +32,18 @@ static void add_quirk(struct mmc_card *card, int data)
 	card->quirks |= data;
 }
 
+/*
+ * This hook just adds a quirk for all sdio devices
+ */
+static void add_quirk_for_sdio_devices(struct mmc_card *card, int data)
+{
+	if (mmc_card_sdio(card))
+		card->quirks |= data;
+}
+
 static const struct mmc_fixup mmc_fixup_methods[] = {
+	{ SDIO_ANY_ID, SDIO_ANY_ID,
+		add_quirk_for_sdio_devices, MMC_QUIRK_BROKEN_CLK_GATING }
 	{ 0 }
 };
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index a498d53..3fe9db0 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -121,6 +121,7 @@ struct mmc_card {
 						/* for byte mode */
 #define MMC_QUIRK_NONSTD_SDIO	(1<<2)		/* non-standard SDIO card attached */
 						/* (missing CIA registers) */
+#define MMC_QUIRK_BROKEN_CLK_GATING (1<<3)	/* clock gating the sdio bus will make card fail */
 
 	unsigned int		erase_size;	/* erase size in sectors */
  	unsigned int		erase_shift;	/* if erase unit is power 2 */
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/