exynos5420: Make USB A-A booting work with early data cache

Apparently the IROM doesn't like data caches... the recently added
dcache-in-bootblock makes A-A booting fail, and flushes/invalidations
alone don't seem to fix it. It's pretty fast anyway, so we just disable
the cache again for the duration of the IROM call.

Also removes a superfluous invalidation line from the bootblock code...
dcache_mmu_enable/disable already take care of that.

Old-Change-Id: I35580d15664c7b4197d4ed14028720147adbf918
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/66602
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit e9c28a6a7a88c8286e62764ee5ad2694da2e822f)

exynos5: Implement booting from SDMMC media

This patch augments the alternative CBFS media source implementation for
Exynos5250 and Exynos5420 to allow booting from SDMMC devices (such as
an SD or uSD card reader, if available). It also moves MMC
initialization for the Snow, Pit and Kirby boards from romstage to
ramstage (mainboard_init) to prevent it from interfering with the IROM
during SDMMC boot.

Old-Change-Id: Ic4adef80c28262d084a53c28ec59aa7ac3af50c8
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/66154
(cherry picked from commit 08de13b72432c076e3327c048df93d89d52b0ecc)

snow and pit: turn on FET4 (for SD card) at bootup

Explictly enable FET4 on Snow and Pit.

Historically we haven't needed to do this because:
* On snow there's a bypass around FET4 which effectively eliminates
  it.  Even if we don't turn on FET4 the SD card is still powered.
  Turning on FET4 doesn't hurt though and is technically correct.
* On pit the EC turns on FET4 on cold bootup.

On pit we run into a problem if the kernel turns off FET4 like in
<https://gerrit.chromium.org/gerrit/#/c/65332/> and then we get a
software reset or warm reset.  In this case the EC won't know to turn
it back on.

This was ported from: https://gerrit.chromium.org/gerrit/#/c/65673

Signed-off-by: David Hendricks <dhendrix@chromium.org>

Old-Change-Id: I57337f12b38889e6afee8577cf8807ec4c41e91c
Reviewed-on: https://gerrit.chromium.org/gerrit/66786
Commit-Queue: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: Ronald G. Minnich <rminnich@chromium.org>
(cherry picked from commit e910117047d898b6b1d0dc965ef2ec0237d17646)

Squashed three commits for alternate cbfs SD support.

Change-Id: Idbd1fd4776cbf8cb20d03e6b691104cd8540a1ec
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6530
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

11 files changed, 209 insertions, 47 deletions

diff --git a/src/cpu/samsung/exynos5250/alternate_cbfs.c b/src/cpu/samsung/exynos5250/alternate_cbfs.c
index 49c9d4c194..59843fb97b 100644
--- a/src/cpu/samsung/exynos5250/alternate_cbfs.c
+++ b/src/cpu/samsung/exynos5250/alternate_cbfs.c
@@ -24,6 +24,8 @@
 #include <string.h>
 #include <console/console.h>
 #include "alternate_cbfs.h"
+#include "cpu.h"
+#include "power.h"
 #include "spi.h"
 
 /* This allows USB A-A firmware upload from a compatible host in four parts:
@@ -53,7 +55,7 @@ static int usb_cbfs_open(struct cbfs_media *media)
 		return 0;
 
 	if (!irom_load_usb()) {
-		printk(BIOS_ERR, "Unable to load CBFS image via USB!\n");
+		printk(BIOS_EMERG, "Unable to load CBFS image via USB!\n");
 		return -1;
 	}
 
@@ -70,6 +72,45 @@ static int usb_cbfs_open(struct cbfs_media *media)
 	return 0;
 }
 
+/*
+ * SDMMC works very similar to USB A-A: we copy the CBFS image into memory
+ * and read it from there. While SDMMC would also allow direct block by block
+ * on-demand reading, we might run into problems if we call back into the IROM
+ * in very late boot stages (e.g. after initializing/changing MMC clocks)... so
+ * this seems like a safer approach. It also makes it easy to pass our image
+ * down to payloads.
+ */
+static int sdmmc_cbfs_open(struct cbfs_media *media)
+{
+#ifdef __PRE_RAM__
+	/*
+	 * In the bootblock, we just copy the small part that fits in the buffer
+	 * and hope that it's enough (since the romstage is currently always the
+	 * first component in the image, this should work out). In the romstage,
+	 * we copy until our buffer is full (currently 12M) to avoid the pain of
+	 * figuring out the true image size from in here. Since this is mainly a
+	 * developer/debug boot mode, those shortcomings should be bearable.
+	 */
+	const u32 count = alternate_cbfs_size / 512;
+	static int first_run = 1;
+	int (*irom_load_sdmmc)(u32 start, u32 count, void *dst) =
+		*irom_sdmmc_read_blocks_ptr;
+
+	if (!first_run)
+		return 0;
+
+	if (!irom_load_sdmmc(1, count, alternate_cbfs_buffer)) {
+		printk(BIOS_EMERG, "Unable to load CBFS image from SDMMC!\n");
+		return -1;
+	}
+
+	printk(BIOS_DEBUG, "SDMMC read successful, CBFS image should now be"
+		" at %p\n", alternate_cbfs_buffer);
+	first_run = 0;
+#endif
+	return 0;
+}
+
 static int alternate_cbfs_close(struct cbfs_media *media) { return 0; }
 
 static size_t alternate_cbfs_read(struct cbfs_media *media, void *dest,
@@ -90,6 +131,19 @@ static void *alternate_cbfs_map(struct cbfs_media *media, size_t offset,
 static void *alternate_cbfs_unmap(struct cbfs_media *media,
 				  const void *buffer) { return 0; }
 
+static int initialize_exynos_sdmmc_cbfs_media(struct cbfs_media *media)
+{
+	printk(BIOS_DEBUG, "Using Exynos alternate boot mode SDMMC\n");
+
+	media->open = sdmmc_cbfs_open;
+	media->close = alternate_cbfs_close;
+	media->read = alternate_cbfs_read;
+	media->map = alternate_cbfs_map;
+	media->unmap = alternate_cbfs_unmap;
+
+	return 0;
+}
+
 static int initialize_exynos_usb_cbfs_media(struct cbfs_media *media)
 {
 	printk(BIOS_DEBUG, "Using Exynos alternate boot mode USB A-A\n");
@@ -108,8 +162,16 @@ int init_default_cbfs_media(struct cbfs_media *media)
 	if (*iram_secondary_base == SECONDARY_BASE_BOOT_USB)
 		return initialize_exynos_usb_cbfs_media(media);
 
-	/* TODO: implement SDMMC (and possibly other) boot mode */
-
-	return initialize_exynos_spi_cbfs_media(media,
-		(void*)CONFIG_CBFS_CACHE_ADDRESS, CONFIG_CBFS_CACHE_SIZE);
+	switch (samsung_get_base_power()->om_stat & OM_STAT_MASK) {
+	case OM_STAT_SDMMC:
+		return initialize_exynos_sdmmc_cbfs_media(media);
+	case OM_STAT_SPI:
+		return initialize_exynos_spi_cbfs_media(media,
+			(void*)CONFIG_CBFS_CACHE_ADDRESS,
+			CONFIG_CBFS_CACHE_SIZE);
+	default:
+		printk(BIOS_EMERG, "Exynos OM_STAT value 0x%x not supported!\n",
+			samsung_get_base_power()->om_stat);
+		return 0;
+	}
 }
diff --git a/src/cpu/samsung/exynos5250/alternate_cbfs.h b/src/cpu/samsung/exynos5250/alternate_cbfs.h
index a26fe61f87..8a8727964b 100644
--- a/src/cpu/samsung/exynos5250/alternate_cbfs.h
+++ b/src/cpu/samsung/exynos5250/alternate_cbfs.h
@@ -30,6 +30,12 @@ void * * const irom_load_image_from_usb_ptr = (void * *)0x02020070;
 #define SECONDARY_BASE_BOOT_USB 0xfeed0002
 u32 * const iram_secondary_base = (u32 *)0x02020018;
 
+/* Values pulled from U-Boot, I think the manual is wrong here (for SPI) */
+#define OM_STAT_SDMMC 0x4
+#define OM_STAT_EMMC  0x8
+#define OM_STAT_SPI  0x14
+#define OM_STAT_MASK 0x7f
+
 #if defined(__BOOT_BLOCK__)
 	/* A small space in IRAM to hold the romstage-only image */
 	void * const alternate_cbfs_buffer = (void *)CONFIG_CBFS_CACHE_ADDRESS;
diff --git a/src/cpu/samsung/exynos5250/power.h b/src/cpu/samsung/exynos5250/power.h
index f349e53ece..5483d92de4 100644
--- a/src/cpu/samsung/exynos5250/power.h
+++ b/src/cpu/samsung/exynos5250/power.h
@@ -42,7 +42,8 @@ void power_enable_hw_thermal_trip(void);
 /* Power Management Unit register map */
 struct exynos5_power {
 	/* Add registers as and when required */
-	uint8_t		reserved1[0x0400];
+	uint32_t	om_stat;		/* 0x0000 */
+	uint8_t		reserved1[0x03fc];
 	uint32_t	sw_reset;		/* 0x0400 */
 	uint8_t		reserved2[0x0304];
 	uint32_t	usb_host_phy_ctrl;	/* 0x0708 */
diff --git a/src/cpu/samsung/exynos5420/alternate_cbfs.c b/src/cpu/samsung/exynos5420/alternate_cbfs.c
index 49c9d4c194..416130305a 100644
--- a/src/cpu/samsung/exynos5420/alternate_cbfs.c
+++ b/src/cpu/samsung/exynos5420/alternate_cbfs.c
@@ -22,8 +22,11 @@
 #include <cbfs.h>  /* This driver serves as a CBFS media source. */
 #include <stdlib.h>
 #include <string.h>
+#include <arch/cache.h>
 #include <console/console.h>
 #include "alternate_cbfs.h"
+#include "cpu.h"
+#include "power.h"
 #include "spi.h"
 
 /* This allows USB A-A firmware upload from a compatible host in four parts:
@@ -52,10 +55,13 @@ static int usb_cbfs_open(struct cbfs_media *media)
 	if (!first_run)
 		return 0;
 
+	dcache_mmu_disable();
 	if (!irom_load_usb()) {
-		printk(BIOS_ERR, "Unable to load CBFS image via USB!\n");
+		dcache_mmu_enable();
+		printk(BIOS_EMERG, "Unable to load CBFS image via USB!\n");
 		return -1;
 	}
+	dcache_mmu_enable();
 
 	/*
 	 * We need to trust the host/irom to copy the image to our
@@ -70,6 +76,48 @@ static int usb_cbfs_open(struct cbfs_media *media)
 	return 0;
 }
 
+/*
+ * SDMMC works very similar to USB A-A: we copy the CBFS image into memory
+ * and read it from there. While SDMMC would also allow direct block by block
+ * on-demand reading, we might run into problems if we call back into the IROM
+ * in very late boot stages (e.g. after initializing/changing MMC clocks)... so
+ * this seems like a safer approach. It also makes it easy to pass our image
+ * down to payloads.
+ */
+static int sdmmc_cbfs_open(struct cbfs_media *media)
+{
+#ifdef __PRE_RAM__
+	/*
+	 * In the bootblock, we just copy the small part that fits in the buffer
+	 * and hope that it's enough (since the romstage is currently always the
+	 * first component in the image, this should work out). In the romstage,
+	 * we copy until our buffer is full (currently 12M) to avoid the pain of
+	 * figuring out the true image size from in here. Since this is mainly a
+	 * developer/debug boot mode, those shortcomings should be bearable.
+	 */
+	const u32 count = alternate_cbfs_size / 512;
+	static int first_run = 1;
+	int (*irom_load_sdmmc)(u32 start, u32 count, void *dst) =
+		*irom_sdmmc_read_blocks_ptr;
+
+	if (!first_run)
+		return 0;
+
+	dcache_mmu_disable();
+	if (!irom_load_sdmmc(1, count, alternate_cbfs_buffer)) {
+		dcache_mmu_enable();
+		printk(BIOS_EMERG, "Unable to load CBFS image from SDMMC!\n");
+		return -1;
+	}
+	dcache_mmu_enable();
+
+	printk(BIOS_DEBUG, "SDMMC read successful, CBFS image should now be"
+		" at %p\n", alternate_cbfs_buffer);
+	first_run = 0;
+#endif
+	return 0;
+}
+
 static int alternate_cbfs_close(struct cbfs_media *media) { return 0; }
 
 static size_t alternate_cbfs_read(struct cbfs_media *media, void *dest,
@@ -90,6 +138,19 @@ static void *alternate_cbfs_map(struct cbfs_media *media, size_t offset,
 static void *alternate_cbfs_unmap(struct cbfs_media *media,
 				  const void *buffer) { return 0; }
 
+static int initialize_exynos_sdmmc_cbfs_media(struct cbfs_media *media)
+{
+	printk(BIOS_DEBUG, "Using Exynos alternate boot mode SDMMC\n");
+
+	media->open = sdmmc_cbfs_open;
+	media->close = alternate_cbfs_close;
+	media->read = alternate_cbfs_read;
+	media->map = alternate_cbfs_map;
+	media->unmap = alternate_cbfs_unmap;
+
+	return 0;
+}
+
 static int initialize_exynos_usb_cbfs_media(struct cbfs_media *media)
 {
 	printk(BIOS_DEBUG, "Using Exynos alternate boot mode USB A-A\n");
@@ -108,8 +169,16 @@ int init_default_cbfs_media(struct cbfs_media *media)
 	if (*iram_secondary_base == SECONDARY_BASE_BOOT_USB)
 		return initialize_exynos_usb_cbfs_media(media);
 
-	/* TODO: implement SDMMC (and possibly other) boot mode */
-
-	return initialize_exynos_spi_cbfs_media(media,
-		(void*)CONFIG_CBFS_CACHE_ADDRESS, CONFIG_CBFS_CACHE_SIZE);
+	switch (samsung_get_base_power()->om_stat & OM_STAT_MASK) {
+	case OM_STAT_SDMMC:
+		return initialize_exynos_sdmmc_cbfs_media(media);
+	case OM_STAT_SPI:
+		return initialize_exynos_spi_cbfs_media(media,
+			(void*)CONFIG_CBFS_CACHE_ADDRESS,
+			CONFIG_CBFS_CACHE_SIZE);
+	default:
+		printk(BIOS_EMERG, "Exynos OM_STAT value 0x%x not supported!\n",
+			samsung_get_base_power()->om_stat);
+		return 0;
+	}
 }
diff --git a/src/cpu/samsung/exynos5420/alternate_cbfs.h b/src/cpu/samsung/exynos5420/alternate_cbfs.h
index 4e9dff9f29..3bb9c760f6 100644
--- a/src/cpu/samsung/exynos5420/alternate_cbfs.h
+++ b/src/cpu/samsung/exynos5420/alternate_cbfs.h
@@ -30,6 +30,12 @@ void * * const irom_load_image_from_usb_ptr = (void * *)0x02020070;
 #define SECONDARY_BASE_BOOT_USB 0xfeed0002
 u32 * const iram_secondary_base = (u32 *)0x02020018;
 
+/* Values pulled from U-Boot, I think the manual is wrong here (for SPI) */
+#define OM_STAT_SDMMC 0x4
+#define OM_STAT_EMMC  0x8
+#define OM_STAT_SPI  0x14
+#define OM_STAT_MASK 0x7f
+
 #if defined(__BOOT_BLOCK__)
 	/* A small space in IRAM to hold the romstage-only image */
 	void * const alternate_cbfs_buffer = (void *)CONFIG_CBFS_CACHE_ADDRESS;
diff --git a/src/cpu/samsung/exynos5420/bootblock.c b/src/cpu/samsung/exynos5420/bootblock.c
index 3df51a7421..1ad75ef493 100644
--- a/src/cpu/samsung/exynos5420/bootblock.c
+++ b/src/cpu/samsung/exynos5420/bootblock.c
@@ -63,7 +63,6 @@ void bootblock_cpu_init(void)
 	mmu_config_range(0, SRAM_START, DCACHE_OFF);
 	mmu_config_range(SRAM_START, SRAM_SIZE, DCACHE_WRITEBACK);
 	mmu_config_range(SRAM_END, 4096 - SRAM_END, DCACHE_OFF);
-	dcache_invalidate_all();
 	dcache_mmu_enable();
 
 	/* For most ARM systems, we have to initialize firmware media source
diff --git a/src/cpu/samsung/exynos5420/power.h b/src/cpu/samsung/exynos5420/power.h
index 665e94c197..4efc84efb2 100644
--- a/src/cpu/samsung/exynos5420/power.h
+++ b/src/cpu/samsung/exynos5420/power.h
@@ -42,7 +42,8 @@ void power_enable_hw_thermal_trip(void);
 /* Power Management Unit register map */
 struct exynos5_power {
 	/* Add registers as and when required */
-	uint8_t		reserved1[0x0400];
+	uint32_t	om_stat;		/* 0x0000 */
+	uint8_t		reserved1[0x03fc];
 	uint32_t	sw_reset;		/* 0x0400 */
 	uint8_t		reserved2[0x0304];
 	uint32_t	usb_host_phy_ctrl;	/* 0x0708 */
diff --git a/src/mainboard/google/pit/mainboard.c b/src/mainboard/google/pit/mainboard.c
index 3ffb824216..9aa8d5cd30 100644
--- a/src/mainboard/google/pit/mainboard.c
+++ b/src/mainboard/google/pit/mainboard.c
@@ -330,6 +330,19 @@ static void disable_usb30_pll(void)
 	gpio_direction_output(usb3_pll_l, 0);
 }
 
+static void setup_storage(void)
+{
+	/* MMC0: Fixed, 8 bit mode, connected with GPIO. */
+	if (clock_set_dwmci(PERIPH_ID_SDMMC0))
+		printk(BIOS_CRIT, "%s: Failed to set MMC0 clock.\n", __func__);
+	exynos_pinmux_sdmmc0();
+
+	/* MMC2: Removable, 4 bit mode, no GPIO. */
+	/* (Must be after romstage to avoid breaking SDMMC boot.) */
+	clock_set_dwmci(PERIPH_ID_SDMMC2);
+	exynos_pinmux_sdmmc2();
+}
+
 static void gpio_init(void)
 {
 	/* Set up the I2C busses. */
@@ -370,6 +383,12 @@ static void backlight_vdd(void)
 	tps65090_thru_ec_fet_set(1);
 }
 
+static void sdmmc_vdd(void)
+{
+	/* Enable FET4, P3.3V_SDCARD */
+	tps65090_thru_ec_fet_set(4);
+}
+
 /* this happens after cpu_init where exynos resources are set */
 static void mainboard_init(device_t dev)
 {
@@ -380,6 +399,7 @@ static void mainboard_init(device_t dev)
 	void *fb_addr = (void *)(get_fb_base_kb() * KiB);
 
 	gpio_init();
+	setup_storage();
 	tmu_init(&exynos5420_tmu_info);
 
 	/* Clock Gating all the unused IP's to save power */
@@ -388,6 +408,8 @@ static void mainboard_init(device_t dev)
 	/* Disable USB3.0 PLL to save 250mW of power */
 	disable_usb30_pll();
 
+	sdmmc_vdd();
+
 	set_vbe_mode_info_valid(&edid, (uintptr_t)fb_addr);
 
 	/*
diff --git a/src/mainboard/google/pit/romstage.c b/src/mainboard/google/pit/romstage.c
index 319ebf97e2..7967a559f2 100644
--- a/src/mainboard/google/pit/romstage.c
+++ b/src/mainboard/google/pit/romstage.c
@@ -40,8 +40,6 @@
 #include <drivers/maxim/max77802/max77802.h>
 #include <device/i2c.h>
 
-#define MMC0_GPIO_PIN	(58)
-
 #define PMIC_I2C_BUS	4
 
 struct pmic_write
@@ -109,18 +107,6 @@ static int setup_power(int is_resume)
 	return error;
 }
 
-static void setup_storage(void)
-{
-	/* MMC0: Fixed, 8 bit mode, connected with GPIO. */
-	if (clock_set_dwmci(PERIPH_ID_SDMMC0))
-		printk(BIOS_CRIT, "%s: Failed to set MMC0 clock.\n", __func__);
-	exynos_pinmux_sdmmc0();
-
-	/* MMC2: Removable, 4 bit mode, no GPIO. */
-	clock_set_dwmci(PERIPH_ID_SDMMC2);
-	exynos_pinmux_sdmmc2();
-}
-
 static void setup_ec(void)
 {
 	/* SPI2 (EC) is slower and needs to work in half-duplex mode with
@@ -270,7 +256,6 @@ void main(void)
 		wakeup();
 	}
 
-	setup_storage();
 	setup_gpio();
 	setup_ec();
 
diff --git a/src/mainboard/google/snow/mainboard.c b/src/mainboard/google/snow/mainboard.c
index 23b7072592..9fc2fe6d26 100644
--- a/src/mainboard/google/snow/mainboard.c
+++ b/src/mainboard/google/snow/mainboard.c
@@ -38,6 +38,8 @@
 
 #include "exynos5250.h"
 
+#define MMC0_GPIO_PIN	(58)
+
 /* convenient shorthand (in MB) */
 #define DRAM_START	(CONFIG_SYS_SDRAM_BASE >> 20)
 #define DRAM_SIZE	CONFIG_DRAM_SIZE_MB
@@ -132,6 +134,7 @@ static void backlight_en(void)
 #define TPS65090_BUS	4	/* Snow-specific */
 
 #define FET1_CTRL	0x0f
+#define FET4_CTRL	0x12
 #define FET6_CTRL	0x14
 
 static void lcd_vdd(void)
@@ -147,6 +150,12 @@ static void backlight_vdd(void)
 	udelay(LCD_T5_DELAY_MS * 1000);
 }
 
+static void sdmmc_vdd(void)
+{
+	/* Enable FET4, P3.3V_SDCARD */
+	tps65090_fet_enable(TPS65090_BUS, FET4_CTRL);
+}
+
 //static struct video_info smdk5250_dp_config = {
 static struct video_info dp_video_info = {
 	/* FIXME: fix video_info struct to use const for name */
@@ -179,6 +188,24 @@ static void disable_usb30_pll(void)
 	gpio_direction_output(usb3_pll_l, 0);
 }
 
+static void setup_storage(void)
+{
+	/* MMC0: Fixed, 8 bit mode, connected with GPIO. */
+	if (clock_set_mshci(PERIPH_ID_SDMMC0))
+		printk(BIOS_CRIT, "%s: Failed to set MMC0 clock.\n", __func__);
+	if (gpio_direction_output(MMC0_GPIO_PIN, 1)) {
+		printk(BIOS_CRIT, "%s: Unable to power on MMC0.\n", __func__);
+	}
+	gpio_set_pull(MMC0_GPIO_PIN, GPIO_PULL_NONE);
+	gpio_set_drv(MMC0_GPIO_PIN, GPIO_DRV_4X);
+	exynos_pinmux_sdmmc0();
+
+	/* MMC2: Removable, 4 bit mode, no GPIO. */
+	/* (Must be after romstage to avoid breaking SDMMC boot.) */
+	clock_set_mshci(PERIPH_ID_SDMMC2);
+	exynos_pinmux_sdmmc2();
+}
+
 static void gpio_init(void)
 {
 	/* Set up the I2C busses. */
@@ -217,6 +244,7 @@ static void mainboard_init(device_t dev)
 	void *fb_addr = (void *)(get_fb_base_kb() * KiB);
 
 	gpio_init();
+	setup_storage();
 
 	i2c_init(TPS65090_BUS, I2C_0_SPEED, I2C_SLAVE);
 	i2c_init(7, I2C_0_SPEED, I2C_SLAVE);
@@ -229,6 +257,8 @@ static void mainboard_init(device_t dev)
 	/* Disable USB3.0 PLL to save 250mW of power */
 	disable_usb30_pll();
 
+	sdmmc_vdd();
+
 	set_vbe_mode_info_valid(&edid, (uintptr_t)fb_addr);
 
 	lcd_vdd();
diff --git a/src/mainboard/google/snow/romstage.c b/src/mainboard/google/snow/romstage.c
index 3a8b5e897d..44074c58bf 100644
--- a/src/mainboard/google/snow/romstage.c
+++ b/src/mainboard/google/snow/romstage.c
@@ -42,7 +42,6 @@
 #include "exynos5250.h"
 
 #define PMIC_BUS	0
-#define MMC0_GPIO_PIN	(58)
 
 static void setup_power(int is_resume)
 {
@@ -96,23 +95,6 @@ static void setup_power(int is_resume)
 	}
 }
 
-static void setup_storage(void)
-{
-	/* MMC0: Fixed, 8 bit mode, connected with GPIO. */
-	if (clock_set_mshci(PERIPH_ID_SDMMC0))
-		printk(BIOS_CRIT, "%s: Failed to set MMC0 clock.\n", __func__);
-	if (gpio_direction_output(MMC0_GPIO_PIN, 1)) {
-		printk(BIOS_CRIT, "%s: Unable to power on MMC0.\n", __func__);
-	}
-	gpio_set_pull(MMC0_GPIO_PIN, GPIO_PULL_NONE);
-	gpio_set_drv(MMC0_GPIO_PIN, GPIO_DRV_4X);
-	exynos_pinmux_sdmmc0();
-
-	/* MMC2: Removable, 4 bit mode, no GPIO. */
-	clock_set_mshci(PERIPH_ID_SDMMC2);
-	exynos_pinmux_sdmmc2();
-}
-
 static void setup_graphics(void)
 {
 	exynos_pinmux_dphpd();
@@ -176,7 +158,6 @@ void main(void)
 		wakeup();
 	}
 
-	setup_storage();
 	setup_gpio();
 	setup_graphics();