ARM: mx50: Add support to get the silicon revision

For MX50, the HW_ADADIG_DIGPROG register in the ANATOP module will
have the correct silicon revision:

Major       Minor   Description
0x50        0x0     TO1.0
0x50        0x1     TO1.1

Signed-off-by: Dinh Nguyen <Dinh.Nguyen@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-mx5/cpu.c

@@ -21,6 +21,7 @@
 static int cpu_silicon_rev = -1;
 
 #define IIM_SREV 0x24
+#define MX50_HW_ADADIG_DIGPROG	0xB0
 
 static int get_mx51_srev(void)
 {
@@ -127,6 +128,44 @@ int mx53_revision(void)
 }
 EXPORT_SYMBOL(mx53_revision);
 
+static int get_mx50_srev(void)
+{
+	void __iomem *anatop = ioremap(MX50_ANATOP_BASE_ADDR, SZ_8K);
+	u32 rev;
+
+	if (!anatop) {
+		cpu_silicon_rev = -EINVAL;
+		return 0;
+	}
+
+	rev = readl(anatop + MX50_HW_ADADIG_DIGPROG);
+	rev &= 0xff;
+
+	iounmap(anatop);
+	if (rev == 0x0)
+		return IMX_CHIP_REVISION_1_0;
+	else if (rev == 0x1)
+		return IMX_CHIP_REVISION_1_1;
+	return 0;
+}
+
+/*
+ * Returns:
+ *	the silicon revision of the cpu
+ *	-EINVAL - not a mx50
+ */
+int mx50_revision(void)
+{
+	if (!cpu_is_mx50())
+		return -EINVAL;
+
+	if (cpu_silicon_rev == -1)
+		cpu_silicon_rev = get_mx50_srev();
+
+	return cpu_silicon_rev;
+}
+EXPORT_SYMBOL(mx50_revision);
+
 static int __init post_cpu_init(void)
 {
 	unsigned int reg;

arch/arm/plat-mxc/include/mach/mx50.h

@@ -282,4 +282,8 @@
 #define MX50_INT_APBHDMA_CHAN6	116
 #define MX50_INT_APBHDMA_CHAN7	117
 
+#if !defined(__ASSEMBLY__) && !defined(__MXC_BOOT_UNCOMPRESS)
+extern int mx50_revision(void);
+#endif
+
 #endif /* ifndef __MACH_MX50_H__ */