imx: cpu: add cpu speed/grade for i.MX8M

Use more general enum types for speed grade.
Refine get_cpu_speed_grade_hz to support i.MX8M.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c
index 52dbafb..fd6d08c 100644
--- a/arch/arm/mach-imx/cpu.c
+++ b/arch/arm/mach-imx/cpu.c
@@ -333,16 +333,18 @@
 }
 #endif
 
-#if defined(CONFIG_MX7)
+#if defined(CONFIG_MX7) || defined(CONFIG_MX8M)
 /*
  * OCOTP_TESTER3[9:8] (see Fusemap Description Table offset 0x440)
  * defines a 2-bit SPEED_GRADING
  */
 #define OCOTP_TESTER3_SPEED_SHIFT	8
-#define OCOTP_TESTER3_SPEED_800MHZ	0
-#define OCOTP_TESTER3_SPEED_500MHZ	1
-#define OCOTP_TESTER3_SPEED_1GHZ	2
-#define OCOTP_TESTER3_SPEED_1P2GHZ	3
+enum cpu_speed {
+	OCOTP_TESTER3_SPEED_GRADE0,
+	OCOTP_TESTER3_SPEED_GRADE1,
+	OCOTP_TESTER3_SPEED_GRADE2,
+	OCOTP_TESTER3_SPEED_GRADE3,
+};
 
 u32 get_cpu_speed_grade_hz(void)
 {
@@ -357,15 +359,16 @@
 	val &= 0x3;
 
 	switch(val) {
-	case OCOTP_TESTER3_SPEED_800MHZ:
+	case OCOTP_TESTER3_SPEED_GRADE0:
 		return 800000000;
-	case OCOTP_TESTER3_SPEED_500MHZ:
-		return 500000000;
-	case OCOTP_TESTER3_SPEED_1GHZ:
-		return 1000000000;
-	case OCOTP_TESTER3_SPEED_1P2GHZ:
-		return 1200000000;
+	case OCOTP_TESTER3_SPEED_GRADE1:
+		return is_mx7() ? 500000000 : 1000000000;
+	case OCOTP_TESTER3_SPEED_GRADE2:
+		return is_mx7() ? 1000000000 : 1300000000;
+	case OCOTP_TESTER3_SPEED_GRADE3:
+		return is_mx7() ? 1200000000 : 1500000000;
 	}
+
 	return 0;
 }