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 --- drivers/mmc/core/core.c | 5 +++-- drivers/mmc/core/sdio_io.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+), 2 deletions(-) (limited to 'drivers/mmc') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 6db36dc870b5..9020cb2490f7 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -144,8 +144,9 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq) 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))) diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c index f79f0b0caab8..0acb1a29c968 100644 --- a/drivers/mmc/core/sdio_io.c +++ b/drivers/mmc/core/sdio_io.c @@ -734,3 +734,40 @@ 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); -- cgit v1.2.3