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Subject[PATCH 5.1 007/121] mmc: core: Add sdio_retune_hold_now() and sdio_retune_release()
Date
From: Douglas Anderson <dianders@chromium.org>

commit b4c9f938d542d5f88c501744d2d12fad4fd2915f upstream.

We want SDIO drivers to be able to temporarily stop retuning when the
driver knows that the SDIO card is not in a state where retuning will
work (maybe because the card is asleep). We'll move the relevant
functions to a place where drivers can call them.

Cc: stable@vger.kernel.org #v4.18+
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mmc/core/sdio_io.c | 40 ++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/sdio_func.h | 3 +++
2 files changed, 43 insertions(+)

--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -19,6 +19,7 @@
#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
@@ -775,3 +776,42 @@ void sdio_retune_crc_enable(struct sdio_
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);
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -162,4 +162,7 @@ extern int sdio_set_host_pm_flags(struct
extern void sdio_retune_crc_disable(struct sdio_func *func);
extern void sdio_retune_crc_enable(struct sdio_func *func);

+extern void sdio_retune_hold_now(struct sdio_func *func);
+extern void sdio_retune_release(struct sdio_func *func);
+
#endif /* LINUX_MMC_SDIO_FUNC_H */

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