atmel_sdhci: SDMMC_CD pin still needed for card detection despite EMMC set to non-removable

[Zixun Li]

Hardware: SAMA5D27 customized board, EMMC connected to SDMMC0. SDMMC0_CD pin pulled-down for BootROM card detection, once booted it used as LED output.

Software: u-boot-at91 76f7f55

Issue:
U-Boot can't detect EMMC despite it set to non-removable in DT, unless SDMMC0_CD pin is used (so this pin can't be used for other purpose)

sdmmc0: sdio-host at a0000000 {
                                                bus-width = <4>;
                                                pinctrl-names = "default";
                                                pinctrl-0 = <&pinctrl_sdmmc0_default>;
                                                status = "okay";
                                                non-removable;
                                                no-1-8-v;
                                };

Workaround: I have to FCD bit of SDMMC_MC1R register.

diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 766e4a6b0c..89ceeaf3c1 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -758,7 +758,12 @@ static int sdhci_get_cd(struct udevice *dev)

        /* If nonremovable, assume that the card is always present. */
        if (mmc->cfg->host_caps & MMC_CAP_NONREMOVABLE)
+       {
+               value = sdhci_readb(host, SDHCI_HOST_MC1R);
+               sdhci_writeb(host, SDHCI_VENDOR_MC1R_FCD | value, SDHCI_HOST_MC1R);
                return 1;
+       }
+
        /* If polling, assume that the card is always present. */
        if (mmc->cfg->host_caps & MMC_CAP_NEEDS_POLL)
                return 1;
diff --git a/include/sdhci.h b/include/sdhci.h
index c718dd7206..61e7ebb2a1 100644
--- a/include/sdhci.h
+++ b/include/sdhci.h
@@ -223,6 +223,9 @@

#define SDHCI_GET_VERSION(x) (x->version & SDHCI_SPEC_VER_MASK)

+#define SDHCI_HOST_MC1R                        0x204
+
+#define SDHCI_VENDOR_MC1R_FCD  0x80
/*
  * End of controller registers.
  */