soc/amd/picasso: Move sd_emmc_config into emmc_config struct

I plan on adding another eMMC parameter. This refactor keeps the config
contained in a single struct.

BUG=b:159823235
TEST=Build test

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: I4b57d651ab44d6c1cad661d620bffd4207dfebd4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45095
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/mainboard/amd/mandolin/mainboard.c

@@ -112,7 +112,7 @@ static void mainboard_init(void *chip_info)
 	struct soc_amd_picasso_config *cfg = config_of_soc();
 
 	if (!CONFIG(PICASSO_LPC_IOMUX))
-		cfg->sd_emmc_config = SD_EMMC_EMMC_HS400;
+		cfg->emmc_config.timing = SD_EMMC_EMMC_HS400;
 
 	mainboard_program_gpios();
 

src/mainboard/amd/mandolin/variants/mandolin/devicetree.cb

@@ -7,7 +7,9 @@ chip soc/amd/picasso
 	register "fadt_boot_arch" = "ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042"
 	register "fadt_flags" = "ACPI_FADT_SLEEP_BUTTON" # See table 5-34 ACPI 6.3 spec
 
-	register "sd_emmc_config" = "SD_EMMC_DISABLE"
+	register "emmc_config" = "{
+		.timing = SD_EMMC_DISABLE,
+	}"
 
 	register "has_usb2_phy_tune_params" = "1"
 

src/mainboard/google/zork/variants/baseboard/devicetree_dalboz.cb

@@ -40,7 +40,9 @@ chip soc/amd/picasso
 
 	# End : OPN Performance Configuration
 
-	register "sd_emmc_config" = "SD_EMMC_EMMC_HS400"
+	register "emmc_config" = "{
+		.timing = SD_EMMC_EMMC_HS400,
+	}"
 
 	register "xhci0_force_gen1" = "0"
 

src/mainboard/google/zork/variants/baseboard/devicetree_trembyle.cb

@@ -40,7 +40,9 @@ chip soc/amd/picasso
 
 	# End : OPN Performance Configuration
 
-	register "sd_emmc_config" = "SD_EMMC_EMMC_HS400"
+	register "emmc_config" = "{
+		.timing = SD_EMMC_EMMC_HS400,
+	}"
 
 	register "xhci0_force_gen1" = "0"
 

src/mainboard/google/zork/variants/dalboz/variant.c

@@ -134,10 +134,10 @@ void variant_devtree_update(void)
 			 * So we keep the speed low here, with the intent that
 			 * other variants implement these corrections.
 			 */
-			cfg->sd_emmc_config = SD_EMMC_EMMC_HS200;
+			cfg->emmc_config.timing = SD_EMMC_EMMC_HS200;
 		}
 	} else {
-		cfg->sd_emmc_config = SD_EMMC_DISABLE;
+		cfg->emmc_config.timing = SD_EMMC_DISABLE;
 	}
 
 	update_audio_configuration();

src/mainboard/google/zork/variants/ezkinil/variant.c

@@ -15,5 +15,5 @@ void variant_devtree_update(void)
 	 * Enable eMMC if eMMC bit is set in FW_CONFIG or device is unprovisioned.
 	 */
 	if (!(variant_has_emmc() || boot_is_factory_unprovisioned()))
-		cfg->sd_emmc_config = SD_EMMC_DISABLE;
+		cfg->emmc_config.timing = SD_EMMC_DISABLE;
 }

src/soc/amd/picasso/chip.h

@@ -126,20 +126,34 @@ struct soc_amd_picasso_config {
 	uint32_t telemetry_vddcr_soc_slope;
 	uint32_t telemetry_vddcr_soc_offset;
 
-	enum {
-		SD_EMMC_DISABLE,
-		SD_EMMC_SD_LOW_SPEED,
-		SD_EMMC_SD_HIGH_SPEED,
-		SD_EMMC_SD_UHS_I_SDR_50,
-		SD_EMMC_SD_UHS_I_DDR_50,
-		SD_EMMC_SD_UHS_I_SDR_104,
-		SD_EMMC_EMMC_SDR_26,
-		SD_EMMC_EMMC_SDR_52,
-		SD_EMMC_EMMC_DDR_52,
-		SD_EMMC_EMMC_HS200,
-		SD_EMMC_EMMC_HS400,
-		SD_EMMC_EMMC_HS300,
-	} sd_emmc_config;
+	struct {
+		/*
+		 * SDHCI doesn't directly support eMMC. There is an implicit mapping between
+		 * eMMC timing modes and SDHCI UHS-I timing modes defined in the linux
+		 * kernel.
+		 *
+		 *  HS    -> UHS_SDR12 (0x00)
+		 *  DDR52 -> UHS_DDR50 (0x04)
+		 *  HS200 -> UHS_SDR104 (0x03)
+		 *  HS400 -> NONE (0x05)
+		 *
+		 * The kernel driver uses a heuristic to determine if HS400 is supported.
+		*/
+		enum {
+			SD_EMMC_DISABLE,
+			SD_EMMC_SD_LOW_SPEED,
+			SD_EMMC_SD_HIGH_SPEED,
+			SD_EMMC_SD_UHS_I_SDR_50,
+			SD_EMMC_SD_UHS_I_DDR_50,
+			SD_EMMC_SD_UHS_I_SDR_104,
+			SD_EMMC_EMMC_SDR_26,
+			SD_EMMC_EMMC_SDR_52,
+			SD_EMMC_EMMC_DDR_52,
+			SD_EMMC_EMMC_HS200,
+			SD_EMMC_EMMC_HS400,
+			SD_EMMC_EMMC_HS300,
+		} timing;
+	} emmc_config;
 
 	uint8_t xhci0_force_gen1;
 

src/soc/amd/picasso/fsp_params.c

@@ -13,7 +13,7 @@ static void fsps_update_emmc_config(FSP_S_CONFIG *scfg,
 {
 	int val = SD_DISABLE;
 
-	switch (cfg->sd_emmc_config) {
+	switch (cfg->emmc_config.timing) {
 	case SD_EMMC_DISABLE:
 		val = SD_DISABLE;
 		break;