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

[Zixun Li]

>  Can't we do this in a different place?
> When we parse the DT for example. If the card is non-removable, this is described as a property in the DT.
> In this way you don't have to recreate all the below code from the common sdhci_get_cd, and you avoid rewriting the MC1R every time the get_cd is called.

The problem is inside sdhci_init() there is a sdhci_reset(), FCD bit will lost if we set it too early.

Then I've looked at the kernel driver, setting this bit is also a workaround of SAMA5D2 series, who doesn't drive CMD if using CD GPIO line.

https://github.com/linux4sam/linux-at91/blob/068eaa6b4b087b3a86fc4624d0f4083844e93f1c/drivers/mmc/host/sdhci-of-at91.c#L551

I've refactored the code, setting FCD bit after sdhci_probe() with a separate function to make the purpose more clear.


From 90177e7af8226b88dfbfc08639f768881562a3a2 Mon Sep 17 00:00:00 2001
From: Zixun LI <zli at ogga.fr>
Date: Thu, 4 May 2023 16:30:41 +0200
Subject: [PATCH] atmel_sdhci: Force card-detect if MMC_CAP_NONREMOVABLE.

---
 drivers/mmc/atmel_sdhci.c | 40 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/atmel_sdhci.c b/drivers/mmc/atmel_sdhci.c
index 37b0beeed4..ae56266f57 100644
--- a/drivers/mmc/atmel_sdhci.c
+++ b/drivers/mmc/atmel_sdhci.c
@@ -15,6 +15,9 @@
 #define ATMEL_SDHC_MIN_FREQ    400000
 #define ATMEL_SDHC_GCK_RATE    240000000

+#define ATMEL_SDHC_MC1R 0x204
+#define ATMEL_SDHC_MC1R_FCD    0x80
+
 #ifndef CONFIG_DM_MMC
 int atmel_sdhci_init(void *regbase, u32 id)
 {
@@ -52,11 +55,38 @@ struct atmel_sdhci_plat {
        struct mmc mmc;
 };

+static void atmel_sdhci_config_fcd(struct sdhci_host *host)
+{
+       u8 mc1r;
+
+       /* If nonremovable, assume that the card is always present.
+        *
+        * WA: SAMA5D2 doesn't drive CMD if using CD GPIO line.
+        */
+       if ((host->mmc->cfg->host_caps & MMC_CAP_NONREMOVABLE)
+#if CONFIG_IS_ENABLED(DM_GPIO)
+               || dm_gpio_get_value(&host->cd_gpio) >= 0
+#endif
+          )
+       {
+               sdhci_readb(host, ATMEL_SDHC_MC1R);
+               mc1r |= ATMEL_SDHC_MC1R_FCD;
+               sdhci_writeb(host, mc1r, ATMEL_SDHC_MC1R);
+       }
+}
+
 static int atmel_sdhci_deferred_probe(struct sdhci_host *host)
 {
        struct udevice *dev = host->mmc->dev;
+       int ret;

-       return sdhci_probe(dev);
+       ret = sdhci_probe(dev);
+       if (ret)
+               return ret;
+
+       atmel_sdhci_config_fcd(host);
+
+       return 0;
 }

 static const struct sdhci_ops atmel_sdhci_ops = {
@@ -120,7 +150,13 @@ static int atmel_sdhci_probe(struct udevice *dev)

        clk_free(&clk);

-       return sdhci_probe(dev);
+       ret = sdhci_probe(dev);
+       if (ret)
+               return ret;
+
+       atmel_sdhci_config_fcd(host);
+
+       return 0;
 }

 static int atmel_sdhci_bind(struct udevice *dev)
--
2.40.1