From 0a55f4ab9678413a01e740c86e9367ba0c612b36 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Mon, 17 Jun 2019 10:56:50 -0700 Subject: mmc: core: API to temporarily disable retuning for SDIO CRC errors Normally when the MMC core sees an "-EILSEQ" error returned by a host controller then it will trigger a retuning of the card. This is generally a good idea. However, if a command is expected to sometimes cause transfer errors then these transfer errors shouldn't cause a re-tuning. This re-tuning will be a needless waste of time. One example case where a transfer is expected to cause errors is when transitioning between idle (sometimes referred to as "sleep" in Broadcom code) and active state on certain Broadcom WiFi SDIO cards. Specifically if the card was already transitioning between states when the command was sent it could cause an error on the SDIO bus. Let's add an API that the SDIO function drivers can call that will temporarily disable the auto-tuning functionality. Then we can add a call to this in the Broadcom WiFi driver and any other driver that might have similar needs. NOTE: this makes the assumption that the card is already tuned well enough that it's OK to disable the auto-retuning during one of these error-prone situations. Presumably the driver code performing the error-prone transfer knows how to recover / retry from errors. ...and after we can get back to a state where transfers are no longer error-prone then we can enable the auto-retuning again. If we truly find ourselves in a case where the card needs to be retuned sometimes to handle one of these error-prone transfers then we can always try a few transfers first without auto-retuning and then re-try with auto-retuning if the first few fail. Without this change on rk3288-veyron-minnie I periodically see this in the logs of a machine just sitting there idle: dwmmc_rockchip ff0d0000.dwmmc: Successfully tuned phase to XYZ Cc: stable@vger.kernel.org #v4.18+ Signed-off-by: Douglas Anderson Acked-by: Adrian Hunter Acked-by: Kalle Valo Signed-off-by: Ulf Hansson --- include/linux/mmc/host.h | 1 + include/linux/mmc/sdio_func.h | 3 +++ 2 files changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 43d0f0c496f6..ecb7972e2423 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -398,6 +398,7 @@ struct mmc_host { unsigned int retune_now:1; /* do re-tuning at next req */ unsigned int retune_paused:1; /* re-tuning is temporarily disabled */ unsigned int use_blk_mq:1; /* use blk-mq */ + unsigned int retune_crc_disable:1; /* don't trigger retune upon crc */ int rescan_disable; /* disable card detection */ int rescan_entered; /* used with nonremovable devices */ diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h index e9dfdd501cd1..4820e6d09dac 100644 --- a/include/linux/mmc/sdio_func.h +++ b/include/linux/mmc/sdio_func.h @@ -167,4 +167,7 @@ extern void sdio_f0_writeb(struct sdio_func *func, unsigned char b, extern mmc_pm_flag_t sdio_get_host_pm_caps(struct sdio_func *func); 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); + #endif /* LINUX_MMC_SDIO_FUNC_H */ -- cgit v1.2.3-59-g8ed1b From b4c9f938d542d5f88c501744d2d12fad4fd2915f Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Mon, 17 Jun 2019 10:56:52 -0700 Subject: mmc: core: Add sdio_retune_hold_now() and sdio_retune_release() 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 Acked-by: Adrian Hunter Acked-by: Kalle Valo Signed-off-by: Ulf Hansson --- drivers/mmc/core/sdio_io.c | 40 ++++++++++++++++++++++++++++++++++++++++ include/linux/mmc/sdio_func.h | 3 +++ 2 files changed, 43 insertions(+) (limited to 'include') 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 */ -- cgit v1.2.3-59-g8ed1b