omap4: Update id.c and cpu.h for es2.0

This patch updates the id.c and cpu.h files to support
omap4 ES2.0 silicon detection. Few initial omap4 es2 samples
IDCODE is same as es1. So the patch uses ARM cpuid register to
detect the ES version for such samples

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
index 9a879f9..91d7df4 100644
--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -298,7 +298,6 @@
 	u32 idcode;
 	u16 hawkeye;
 	u8 rev;
-	char *rev_name = "ES1.0";
 
 	/*
 	 * The IC rev detection is done with hawkeye and rev.
@@ -309,14 +308,39 @@
 	hawkeye = (idcode >> 12) & 0xffff;
 	rev = (idcode >> 28) & 0xff;
 
-	if ((hawkeye == 0xb852) && (rev == 0x0)) {
-		omap_revision = OMAP4430_REV_ES1_0;
-		omap_chip.oc |= CHIP_IS_OMAP4430ES1;
-		pr_info("OMAP%04x %s\n", omap_rev() >> 16, rev_name);
-		return;
+	/*
+	 * Few initial ES2.0 samples IDCODE is same as ES1.0
+	 * Use ARM register to detect the correct ES version
+	 */
+	if (!rev) {
+		idcode = read_cpuid(CPUID_ID);
+		rev = (idcode & 0xf) - 1;
 	}
 
-	pr_err("Unknown OMAP4 CPU id\n");
+	switch (hawkeye) {
+	case 0xb852:
+		switch (rev) {
+		case 0:
+			omap_revision = OMAP4430_REV_ES1_0;
+			omap_chip.oc |= CHIP_IS_OMAP4430ES1;
+			break;
+		case 1:
+			omap_revision = OMAP4430_REV_ES2_0;
+			omap_chip.oc |= CHIP_IS_OMAP4430ES2;
+			break;
+		default:
+			omap_revision = OMAP4430_REV_ES2_0;
+			omap_chip.oc |= CHIP_IS_OMAP4430ES2;
+	}
+	break;
+	default:
+		/* Unknown default to latest silicon rev as default*/
+		omap_revision = OMAP4430_REV_ES2_0;
+		omap_chip.oc |= CHIP_IS_OMAP4430ES2;
+	}
+
+	pr_info("OMAP%04x ES%d.0\n",
+			omap_rev() >> 16, ((omap_rev() >> 12) & 0xf) + 1);
 }
 
 #define OMAP3_SHOW_FEATURE(feat)		\