ARM: mx35: Add mx35_revision function to query the silicon revision

Based on work done earlier by Sascha Hauer

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Eric Bénard <eric@eukrea.com>
[ukl: actually squash the two approaches together]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-mx3/cpu.c b/arch/arm/mach-mx3/cpu.c
index 47b0573..d00a754 100644
--- a/arch/arm/mach-mx3/cpu.c
+++ b/arch/arm/mach-mx3/cpu.c
@@ -55,3 +55,30 @@
 
 	printk(KERN_WARNING "Unknown CPU identifier. srev = %02x\n", srev);
 }
+
+unsigned int mx35_cpu_rev;
+EXPORT_SYMBOL(mx35_cpu_rev);
+
+void __init mx35_read_cpu_rev(void)
+{
+	u32 rev;
+	char *srev = "unknown";
+
+	rev = __raw_readl(MX35_IO_ADDRESS(MX35_IIM_BASE_ADDR + MXC_IIMSREV));
+	switch (rev) {
+	case 0x00:
+		mx35_cpu_rev = MX3x_CHIP_REV_1_0;
+		srev = "1.0";
+		break;
+	case 0x10:
+		mx35_cpu_rev = MX3x_CHIP_REV_2_0;
+		srev = "2.0";
+		break;
+	case 0x11:
+		mx35_cpu_rev = MX3x_CHIP_REV_2_1;
+		srev = "2.1";
+		break;
+	}
+
+	printk(KERN_INFO "CPU identified as i.MX35, silicon rev %s\n", srev);
+}