cmd_mmc.c: Add bootbus mmc sub-command

Add a bootbus sub-command to the mmc command to allow for setting
the boot_bus_width, reset_boot_bus_width and boot_mode fields of
BOOT_BUS_WIDTH (EXT_CSD[177]).

Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Tom Rini <trini@ti.com>
Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>

common/cmd_mmc.c

@@ -338,6 +338,33 @@ static int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 		/* acknowledge to be sent during boot operation */
 		return mmc_set_part_conf(mmc, ack, part_num, access);
+	} else if (strcmp(argv[1], "bootbus") == 0) {
+		int dev;
+		struct mmc *mmc;
+		u8 width, reset, mode;
+
+		if (argc == 6) {
+			dev = simple_strtoul(argv[2], NULL, 10);
+			width = simple_strtoul(argv[3], NULL, 10);
+			reset = simple_strtoul(argv[4], NULL, 10);
+			mode = simple_strtoul(argv[5], NULL, 10);
+		} else {
+			return CMD_RET_USAGE;
+		}
+
+		mmc = find_mmc_device(dev);
+		if (!mmc) {
+			printf("no mmc device at slot %x\n", dev);
+			return 1;
+		}
+
+		if (IS_SD(mmc)) {
+			puts("BOOT_BUS_WIDTH only exists on eMMC\n");
+			return 1;
+		}
+
+		/* acknowledge to be sent during boot operation */
+		return mmc_set_boot_bus_width(mmc, width, reset, mode);
 	} else if (strcmp(argv[1], "bootpart-resize") == 0) {
 		int dev;
 		struct mmc *mmc;
@@ -475,6 +502,8 @@ U_BOOT_CMD(
 	" - Enable boot_part for booting and enable R/W access of boot_part\n"
 	"mmc close <dev> <boot_partition>\n"
 	" - Enable boot_part for booting and disable access to boot_part\n"
+	"mmc bootbus dev boot_bus_width reset_boot_bus_width boot_mode\n"
+	" - Set the BOOT_BUS_WIDTH field of the specified device\n"
 	"mmc bootpart-resize <dev> <boot part size MB> <RPMB part size MB>\n"
 	" - Change sizes of boot and RPMB partitions of specified device\n"
 	"mmc partconf dev boot_ack boot_partition partition_access\n"

drivers/mmc/mmc.c

@@ -1507,6 +1507,27 @@ int mmc_boot_part_access(struct mmc *mmc, u8 ack, u8 part_num, u8 access)
 }
 
 /*
+ * Modify EXT_CSD[177] which is BOOT_BUS_WIDTH
+ * based on the passed in values for BOOT_BUS_WIDTH, RESET_BOOT_BUS_WIDTH
+ * and BOOT_MODE.
+ *
+ * Returns 0 on success.
+ */
+int mmc_set_boot_bus_width(struct mmc *mmc, u8 width, u8 reset, u8 mode)
+{
+	int err;
+
+	err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BOOT_BUS_WIDTH,
+			 EXT_CSD_BOOT_BUS_WIDTH_MODE(mode) |
+			 EXT_CSD_BOOT_BUS_WIDTH_RESET(reset) |
+			 EXT_CSD_BOOT_BUS_WIDTH_WIDTH(width));
+
+	if (err)
+		return err;
+	return 0;
+}
+
+/*
  * Modify EXT_CSD[179] which is PARTITION_CONFIG (formerly BOOT_CONFIG)
  * based on the passed in values for BOOT_ACK, BOOT_PARTITION_ENABLE and
  * PARTITION_ACCESS.

include/mmc.h

@@ -187,6 +187,9 @@
 #define EXT_CSD_BOOT_PART_NUM(x)	(x << 3)
 #define EXT_CSD_PARTITION_ACCESS(x)	(x << 0)
 
+#define EXT_CSD_BOOT_BUS_WIDTH_MODE(x)	(x << 3)
+#define EXT_CSD_BOOT_BUS_WIDTH_RESET(x)	(x << 2)
+#define EXT_CSD_BOOT_BUS_WIDTH_WIDTH(x)	(x)
 
 #define R1_ILLEGAL_COMMAND		(1 << 22)
 #define R1_APP_CMD			(1 << 5)
@@ -314,6 +317,8 @@ int mmc_boot_partition_size_change(struct mmc *mmc, unsigned long bootsize,
 int mmc_boot_part_access(struct mmc *mmc, u8 ack, u8 part_num, u8 access);
 /* Function to modify the PARTITION_CONFIG field of EXT_CSD */
 int mmc_set_part_conf(struct mmc *mmc, u8 ack, u8 part_num, u8 access);
+/* Function to modify the BOOT_BUS_WIDTH field of EXT_CSD */
+int mmc_set_boot_bus_width(struct mmc *mmc, u8 width, u8 reset, u8 mode);
 
 /**
  * Start device initialization and return immediately; it does not block on