1 files changed, 77 insertions, 0 deletions

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index d40744bbafa9..ed2d8c48ea17 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -18,6 +18,7 @@
 #include "sdio_ops.h"
 #include "core.h"
 #include "card.h"
+#include "host.h"
 
 /**
  *	sdio_claim_host - exclusively claim a bus for a certain SDIO function
@@ -725,3 +726,79 @@ int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(sdio_set_host_pm_flags);
+
+/**
+ *	sdio_retune_crc_disable - temporarily disable retuning on CRC errors
+ *	@func: SDIO function attached to host
+ *
+ *	If the SDIO card is known to be in a state where it might produce
+ *	CRC errors on the bus in response to commands (like if we know it is
+ *	transitioning between power states), an SDIO function driver can
+ *	call this function to temporarily disable the SD/MMC core behavior of
+ *	triggering an automatic retuning.
+ *
+ *	This function should be called while the host is claimed and the host
+ *	should remain claimed until sdio_retune_crc_enable() is called.
+ *	Specifically, the expected sequence of calls is:
+ *	- sdio_claim_host()
+ *	- sdio_retune_crc_disable()
+ *	- some number of calls like sdio_writeb() and sdio_readb()
+ *	- sdio_retune_crc_enable()
+ *	- sdio_release_host()
+ */
+void sdio_retune_crc_disable(struct sdio_func *func)
+{
+	func->card->host->retune_crc_disable = true;
+}
+EXPORT_SYMBOL_GPL(sdio_retune_crc_disable);
+
+/**
+ *	sdio_retune_crc_enable - re-enable retuning on CRC errors
+ *	@func: SDIO function attached to host
+ *
+ *	This is the compement to sdio_retune_crc_disable().
+ */
+void sdio_retune_crc_enable(struct sdio_func *func)
+{
+	func->card->host->retune_crc_disable = false;
+}
+EXPORT_SYMBOL_GPL(sdio_retune_crc_enable);
+
+/**
+ *	sdio_retune_hold_now - start deferring retuning requests till release
+ *	@func: SDIO function attached to host
+ *
+ *	This function can be called if it's currently a bad time to do
+ *	a retune of the SDIO card.  Retune requests made during this time
+ *	will be held and we'll actually do the retune sometime after the
+ *	release.
+ *
+ *	This function could be useful if an SDIO card is in a power state
+ *	where it can respond to a small subset of commands that doesn't
+ *	include the retuning command.  Care should be taken when using
+ *	this function since (presumably) the retuning request we might be
+ *	deferring was made for a good reason.
+ *
+ *	This function should be called while the host is claimed.
+ */
+void sdio_retune_hold_now(struct sdio_func *func)
+{
+	mmc_retune_hold_now(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_retune_hold_now);
+
+/**
+ *	sdio_retune_release - signal that it's OK to retune now
+ *	@func: SDIO function attached to host
+ *
+ *	This is the complement to sdio_retune_hold_now().  Calling this
+ *	function won't make a retune happen right away but will allow
+ *	them to be scheduled normally.
+ *
+ *	This function should be called while the host is claimed.
+ */
+void sdio_retune_release(struct sdio_func *func)
+{
+	mmc_retune_release(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_retune_release);