From: Douglas Anderson dianders@chromium.org
commit 0a55f4ab9678413a01e740c86e9367ba0c612b36 upstream.
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 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/core.c | 5 +++-- drivers/mmc/core/sdio_io.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/mmc/host.h | 1 + include/linux/mmc/sdio_func.h | 3 +++ 4 files changed, 44 insertions(+), 2 deletions(-)
--- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -144,8 +144,9 @@ void mmc_request_done(struct mmc_host *h int err = cmd->error;
/* Flag re-tuning needed on CRC errors */ - if ((cmd->opcode != MMC_SEND_TUNING_BLOCK && - cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200) && + if (cmd->opcode != MMC_SEND_TUNING_BLOCK && + cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200 && + !host->retune_crc_disable && (err == -EILSEQ || (mrq->sbc && mrq->sbc->error == -EILSEQ) || (mrq->data && mrq->data->error == -EILSEQ) || (mrq->stop && mrq->stop->error == -EILSEQ))) --- a/drivers/mmc/core/sdio_io.c +++ b/drivers/mmc/core/sdio_io.c @@ -725,3 +725,40 @@ int sdio_set_host_pm_flags(struct sdio_f 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); --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -395,6 +395,7 @@ 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 */ --- a/include/linux/mmc/sdio_func.h +++ b/include/linux/mmc/sdio_func.h @@ -159,4 +159,7 @@ extern void sdio_f0_writeb(struct sdio_f 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 */