MMC cards need at least 74 clock pulses before any bus communication can occur. The i.MX SDHC controller auto-gates the clock when inactive, so if the SD enumeration is skipped for slots where we know that only a MMC card can be present (which is possible since b5289b742a89 "mmc: allow skipping SD card initialization") those inititialization clock pulses won't be sent out, resulting in command timeouts when trying to enumerate the card. Luckily the eSDHC controller has a hardware feature to send out 80 clock pulses. This has been validated to be available by checking the reference manual back to i.MX25. Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> --- drivers/mci/imx-esdhc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/mci/imx-esdhc.c b/drivers/mci/imx-esdhc.c index c4daa9d12136..db96a813971a 100644 --- a/drivers/mci/imx-esdhc.c +++ b/drivers/mci/imx-esdhc.c @@ -455,10 +455,13 @@ static void set_sysctl(struct mci_host *mci, u32 clock) wait_on_timeout(10 * MSECOND, esdhc_read32(regs + SDHCI_PRESENT_STATE) & PRSSTAT_SDSTB); - clk = SYSCTL_PEREN | SYSCTL_CKEN; + clk = SYSCTL_PEREN | SYSCTL_CKEN | SYSCTL_INITA; esdhc_setbits32(regs + SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET, clk); + + wait_on_timeout(1 * MSECOND, + !(esdhc_read32(regs + SDHCI_CLOCK_CONTROL) & SYSCTL_INITA)); } static void esdhc_set_ios(struct mci_host *mci, struct mci_ios *ios) -- 2.18.0 _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
