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 Signed-off-by: Douglas Anderson dianders@chromium.org Acked-by: Adrian Hunter adrian.hunter@intel.com --- Patches #2 - #5 will go through Ulf's tree.

I've CCed stable@ here without a version tag. As per Adrian Hunter this patch applies cleanly to 4.18+ so that would be an easy first target. However, if someone were so inclined they could provide further backports. As per Adrian [1] the root problem has existed for ~4 years.

[1] https://lkml.kernel.org/r/4f39e152-04ba-a64e-985a-df93e6d15ff8@intel.com

Changes in v5: None Changes in v4: - Moved retune hold/release to SDIO API (Adrian).

Changes in v3: - ("mmc: core: Export mmc_retune_hold_now() mmc_retune_release()") new for v3.

Changes in v2: None

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

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c index 0acb1a29c968..2ba00acf64e6 100644 --- a/drivers/mmc/core/sdio_io.c +++ b/drivers/mmc/core/sdio_io.c @@ -15,6 +15,7 @@ #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 @@ -771,3 +772,42 @@ 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); diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h index 4820e6d09dac..5a177f7a83c3 100644 --- a/include/linux/mmc/sdio_func.h +++ b/include/linux/mmc/sdio_func.h @@ -170,4 +170,7 @@ extern int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags); 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 */