stm32mp1: board: add environment variable for board id and board rev

Add variable to identify board with HW id (read from OTP)
and revision.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
index 279c7b7..fdc4af3 100644
--- a/board/st/stm32mp1/stm32mp1.c
+++ b/board/st/stm32mp1/stm32mp1.c
@@ -539,6 +539,10 @@
 #ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 	const void *fdt_compat;
 	int fdt_compat_len;
+	int ret;
+	u32 otp;
+	struct udevice *dev;
+	char buf[10];
 
 	fdt_compat = fdt_getprop(gd->fdt_blob, 0, "compatible",
 				 &fdt_compat_len);
@@ -548,6 +552,21 @@
 		else
 			env_set("board_name", fdt_compat + 3);
 	}
+	ret = uclass_get_device_by_driver(UCLASS_MISC,
+					  DM_GET_DRIVER(stm32mp_bsec),
+					  &dev);
+
+	if (!ret)
+		ret = misc_read(dev, STM32_BSEC_SHADOW(BSEC_OTP_BOARD),
+				&otp, sizeof(otp));
+	if (!ret && otp) {
+		snprintf(buf, sizeof(buf), "0x%04x", otp >> 16);
+		env_set("board_id", buf);
+
+		snprintf(buf, sizeof(buf), "0x%04x",
+			 ((otp >> 8) & 0xF) - 1 + 0xA);
+		env_set("board_rev", buf);
+	}
 #endif
 
 	/* for DK1/DK2 boards */