ARM: mx51: Print silicon revision on boot

Having the silicon revision to appear on the boot log is a useful information.

MX31 and MX35 already show the silicon revision on boot.

Add support for displaying such information for MX51 as well.

Tested on a MX51EVK, where it shows:

CPU identified as i.MX51, silicon rev 3.0

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-mx5/cpu.c b/arch/arm/mach-mx5/cpu.c
index df46b5e..3b4c307 100644
--- a/arch/arm/mach-mx5/cpu.c
+++ b/arch/arm/mach-mx5/cpu.c
@@ -51,6 +51,26 @@
 }
 EXPORT_SYMBOL(mx51_revision);
 
+void mx51_display_revision(void)
+{
+	int rev;
+	char *srev;
+	rev = mx51_revision();
+
+	switch (rev) {
+	case IMX_CHIP_REVISION_2_0:
+		srev = IMX_CHIP_REVISION_2_0_STRING;
+		break;
+	case IMX_CHIP_REVISION_3_0:
+		srev = IMX_CHIP_REVISION_3_0_STRING;
+		break;
+	default:
+		srev = IMX_CHIP_REVISION_UNKNOWN_STRING;
+	}
+	printk(KERN_INFO "CPU identified as i.MX51, silicon rev %s\n", srev);
+}
+EXPORT_SYMBOL(mx51_display_revision);
+
 #ifdef CONFIG_NEON
 
 /*