soc: imx: add i.MX51/i.MX53 unique id support

i.MX51 and i.MX53 SoCs have a 64-bit SoC unique ID stored in IIM,
which can be used as SoC serial number. The same feature is already
implemented for i.MX6/i.MX7, so this complements support to earlier
SoCs.

Signed-off-by: Sebastian Reichel <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

drivers/soc/imx/soc-imx.c

···
 #include <soc/imx/cpu.h>
 #include <soc/imx/revision.h>
 
+#define IIM_UID		0x820
+
 #define OCOTP_UID_H	0x420
 #define OCOTP_UID_L	0x410
 
···
 	u64 soc_uid = 0;
 	u32 val;
 	int ret;
+	int i;
 
 	if (of_machine_is_compatible("fsl,ls1021a"))
 		return 0;
···
 		soc_id = "i.MX35";
 		break;
 	case MXC_CPU_MX51:
+		ocotp_compat = "fsl,imx51-iim";
 		soc_id = "i.MX51";
 		break;
 	case MXC_CPU_MX53:
+		ocotp_compat = "fsl,imx53-iim";
 		soc_id = "i.MX53";
 		break;
 	case MXC_CPU_IMX6SL:
···
 			regmap_read(ocotp, OCOTP_ULP_UID_1, &val);
 			soc_uid <<= 16;
 			soc_uid |= val & 0xffff;
+		} else if (__mxc_cpu_type == MXC_CPU_MX51 ||
+			   __mxc_cpu_type == MXC_CPU_MX53) {
+			for (i=0; i < 8; i++) {
+				regmap_read(ocotp, IIM_UID + i*4, &val);
+				soc_uid <<= 8;
+				soc_uid |= (val & 0xff);
+			}
 		} else {
 			regmap_read(ocotp, OCOTP_UID_H, &val);
 			soc_uid = val;