mmc: make UHS optionaltoradex_imx_v2017.03_4.9.51_imx8_beta2-bring_up

Use Kconfig to select whether UHS should be supported. This works
around issues with UHS seen on Apalis Evaluation board with some
SD cards. It seems that tuning fails. The exact reason is not known,
but since pull-ups on the carrier board are 3.3V, and UHS requires
1.8V, UHS modes should not be used by default anyway.

Inspired-by commit f99c2efe5672 ("mmc: make UHS and HS200 optional")
Signed-off-by: Stefan Agner <stefan.agner@toradex.com>

3 files changed, 27 insertions, 1 deletions

diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 01d1dbfb1b..ec119522af 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -36,6 +36,13 @@ config DM_MMC_OPS
 
 if MMC
 
+config MMC_UHS_SUPPORT
+	bool "enable UHS support"
+	help
+	  The Ultra High Speed (UHS) bus is available on some SDHC and SDXC
+	  cards. The IO voltage must be switchable from 3.3v to 1.8v. The bus
+	  frequency can go up to 208MHz (SDR104)
+
 config SPL_MMC_TINY
 	bool "Tiny MMC framework in SPL"
 	help
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index a0c804e4b5..a42b87c02c 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -32,7 +32,6 @@ static const unsigned int sd_au_size[] = {
 };
 static int mmc_set_signal_voltage(struct mmc *mmc, uint signal_voltage);
 static void mmc_power_cycle(struct mmc *mmc);
-static int mmc_card_busy(struct mmc *mmc);
 static int mmc_select_mode_and_width(struct mmc *mmc, uint card_caps);
 
 #if CONFIG_IS_ENABLED(MMC_TINY)
@@ -161,11 +160,13 @@ const char *mmc_mode_name(enum bus_mode mode)
 	      [SD_LEGACY]	= "SD Legacy",
 	      [MMC_HS]		= "MMC High Speed (26MHz)",
 	      [SD_HS]		= "SD High Speed (50MHz)",
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 	      [UHS_SDR12]	= "UHS SDR12 (25MHz)",
 	      [UHS_SDR25]	= "UHS SDR25 (50MHz)",
 	      [UHS_SDR50]	= "UHS SDR50 (100MHz)",
 	      [UHS_SDR104]	= "UHS SDR104 (208MHz)",
 	      [UHS_DDR50]	= "UHS DDR50 (50MHz)",
+#endif
 	      [MMC_HS_52]	= "MMC High Speed (52MHz)",
 	      [MMC_DDR_52]	= "MMC DDR52 (52MHz)",
 	      [MMC_HS_200]	= "HS200 (200MHz)",
@@ -486,6 +487,7 @@ static int mmc_go_idle(struct mmc *mmc)
 	return 0;
 }
 
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 static int mmc_switch_voltage(struct mmc *mmc, int signal_voltage)
 {
 	struct mmc_cmd cmd;
@@ -546,6 +548,7 @@ static int mmc_switch_voltage(struct mmc *mmc, int signal_voltage)
 fail:
 	return -EIO;
 }
+#endif
 
 static int sd_send_op_cond(struct mmc *mmc, bool uhs_en)
 {
@@ -612,12 +615,14 @@ static int sd_send_op_cond(struct mmc *mmc, bool uhs_en)
 
 	mmc->ocr = cmd.response[0];
 
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 	if (!(mmc_host_is_spi(mmc)) && (cmd.response[0] & 0x41000000)
 	    == 0x41000000) {
 		err = mmc_switch_voltage(mmc, MMC_SIGNAL_VOLTAGE_180);
 		if (err)
 			return err;
 	}
+#endif
 
 	mmc->high_capacity = ((mmc->ocr & OCR_HCS) == OCR_HCS);
 	mmc->rca = 0;
@@ -1174,7 +1179,9 @@ static int sd_get_capabilities(struct mmc *mmc)
 	ALLOC_CACHE_ALIGN_BUFFER(uint, switch_status, 16);
 	struct mmc_data data;
 	int timeout;
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 	u32 sd3_bus_mode;
+#endif
 
 	mmc->card_caps = MMC_MODE_1BIT;
 
@@ -1257,6 +1264,7 @@ retry_scr:
 		mmc->card_caps |= MMC_CAP(SD_HS);
 
 	/* Version before 3.0 don't support UHS modes */
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 	if (mmc->version < SD_VERSION_3)
 		return 0;
 
@@ -1271,6 +1279,7 @@ retry_scr:
 		mmc->card_caps |= MMC_CAP(UHS_SDR12);
 	if (sd3_bus_mode & SD_MODE_UHS_DDR50)
 		mmc->card_caps |= MMC_CAP(UHS_DDR50);
+#endif
 
 	return 0;
 }
@@ -1454,6 +1463,7 @@ static int mmc_set_vdd(struct mmc *mmc, bool enable)
 	return ret;
 }
 
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 static int mmc_card_busy(struct mmc *mmc)
 {
 	int ret = 0;
@@ -1463,6 +1473,7 @@ static int mmc_card_busy(struct mmc *mmc)
 
 	return ret;
 }
+#endif
 
 static int mmc_set_ios(struct mmc *mmc)
 {
@@ -1568,7 +1579,11 @@ static int sd_select_mode_and_width(struct mmc *mmc, uint card_caps)
 	int err;
 	uint widths[] = {MMC_MODE_4BIT, MMC_MODE_1BIT};
 	const struct mode_width_tuning *mwt;
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 	bool uhs_en = (mmc->ocr & OCR_S18R) ? true : false;
+#else
+	bool uhs_en = false;
+#endif
 	uint caps;
 
 
diff --git a/include/mmc.h b/include/mmc.h
index 75b8e713f4..8d17ea025a 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -530,7 +530,11 @@ static inline bool mmc_is_mode_ddr(enum bus_mode mode)
 
 static inline bool supports_uhs(uint caps)
 {
+#if CONFIG_IS_ENABLED(MMC_UHS_SUPPORT)
 	return (caps & UHS_CAPS) ? true : false;
+#else
+	return false;
+#endif
 }