From: Haibo Chen <haibo.chen@xxxxxxx> USDHC IP has one limitation: the tuning circuit can't handle the async sdio device interrupt correctly. When sdio device use 4 data lines, async sdio interrupt will use the shared DAT[1], if enable auto tuning circuit to check these 4 data lines, include the DAT[1], this circuit will detect this interrupt, take this as data on DAT[1], and adjust the delay cell wrongly, finally will cause the DATA/CMD CRC error. So for SDIO device, only enable DAT[0] and CMD line for auto tuning. Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx> --- drivers/mmc/host/sdhci-esdhc-imx.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c index bf8d6f60a9ee..d6ce4c8d23dc 100644 --- a/drivers/mmc/host/sdhci-esdhc-imx.c +++ b/drivers/mmc/host/sdhci-esdhc-imx.c @@ -448,6 +448,20 @@ static inline void usdhc_auto_tuning_mode_sel_and_en(struct sdhci_host *host) break; } + /* + * For USDHC, auto tuning circuit can not handle the async sdio + * device interrupt correctly. When sdio device use 4 data lines, + * async sdio interrupt will use the shared DAT[1], if enable auto + * tuning circuit check these 4 data lines, include the DAT[1], + * this circuit will detect this interrupt, take this as a data on + * DAT[1], and adjust the delay cell wrongly. + * This is the hardware design limitation, to avoid this, for sdio + * device, config the auto tuning circuit only check DAT[0] and CMD + * line. + */ + if (!host->mmc->card && mmc_card_sdio(host->mmc->card)) + auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_1BIT_EN; + esdhc_clrset_le(host, ESDHC_VEND_SPEC2_AUTO_TUNE_MODE_MASK, auto_tune_buswidth | ESDHC_VEND_SPEC2_AUTO_TUNE_CMD_EN, ESDHC_VEND_SPEC2); -- 2.34.1
