[PATCH] cmd: mmc: check whether bootbus's arguments is valid or not

[Jaehoon Chung]

According to Specification, each bit have valid value.
But it doesn't check whether arguments is valid or not.
It has potential bug with arguments passed by wrong value.

Signed-off-by: Jaehoon Chung <jh80.chung at samsung.com>
---
 cmd/mmc.c | 39 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/cmd/mmc.c b/cmd/mmc.c
index cb6b59f36a43..f9cb3fc21da0 100644
--- a/cmd/mmc.c
+++ b/cmd/mmc.c
@@ -735,8 +735,45 @@ static int do_mmc_bootbus(struct cmd_tbl *cmdtp, int flag,
 		return CMD_RET_FAILURE;
 	}
 
+	/*
+	 * BOOT_BUS_CONDITIONS[177]
+	 * BOOT_MODE[4:3]
+	 * 0x0 : Use SDR + Backward compatible timing in boot operation
+	 * 0x1 : Use SDR + High Speed Timing in boot operation mode
+	 * 0x2 : Use DDR in boot operation
+	 * RESET_BOOT_BUS_CONDITIONS
+	 * 0x0 : Reset bus width to x1, SDR, Backward compatible
+	 * 0x1 : Retain BOOT_BUS_WIDTH and BOOT_MODE
+	 * BOOT_BUS_WIDTH
+	 * 0x0 : x1(sdr) or x4 (ddr) buswidth
+	 * 0x1 : x4(sdr/ddr) buswith
+	 * 0x2 : x8(sdr/ddr) buswith
+	 *
+	 */
+	if (width >= 0x3) {
+		printf("boot_bus_width %d is invalid\n", width);
+		return CMD_RET_FAILURE;
+	}
+
+	if (reset >= 0x2) {
+		printf("reset_boot_bus_width %d is invalid\n", reset);
+		return CMD_RET_FAILURE;
+	}
+
+	if (mode >= 0x3) {
+		printf("reset_boot_bus_width %d is invalid\n", mode);
+		return CMD_RET_FAILURE;
+	}
+
 	/* acknowledge to be sent during boot operation */
-	return mmc_set_boot_bus_width(mmc, width, reset, mode);
+	if (mmc_set_boot_bus_width(mmc, width, reset, mode)) {
+		puts("BOOT_BUS_WIDTH is failed to change.\n");
+		return CMD_RET_FAILURE;
+	}
+
+	printf("Set to BOOT_BUS_WIDTH = 0x%x, RESET = 0x%x, BOOT_MODE = 0x%x\n",
+			width, reset, mode);
+	return CMD_RET_SUCCESS;
 }
 
 static int do_mmc_boot_resize(struct cmd_tbl *cmdtp, int flag,
-- 
2.29.0