ARM: mx31: Print the silicon version

Use the same method of the Linux kernel to print the MX31 silicon version on
boot.

Tested on a MX31PDK with a 2.0 silicon, where it shows:

CPU:   Freescale i.MX31 rev 2.0 at 531 MHz

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

arch/arm/cpu/arm1136/mx31/generic.c

@@ -106,11 +106,37 @@ void mx31_set_pad(enum iomux_pins pin, u32 config)
 
 }
 
+struct mx3_cpu_type mx31_cpu_type[] = {
+	{ .srev = 0x00,	.v = "1.0"  },
+	{ .srev = 0x10,	.v = "1.1"  },
+	{ .srev = 0x11,	.v = "1.1"  },
+	{ .srev = 0x12,	.v = "1.15" },
+	{ .srev = 0x13,	.v = "1.15" },
+	{ .srev = 0x14,	.v = "1.2"  },
+	{ .srev = 0x15,	.v = "1.2"  },
+	{ .srev = 0x28,	.v = "2.0"  },
+	{ .srev = 0x29,	.v = "2.0"  },
+};
+
+char *get_cpu_rev(void)
+{
+	u32 i, srev;
+
+	/* read SREV register from IIM module */
+	struct iim_regs *iim = (struct iim_regs *)MX31_IIM_BASE_ADDR;
+	srev = readl(&iim->iim_srev);
+
+	for (i = 0; i < ARRAY_SIZE(mx31_cpu_type); i++)
+		if (srev == mx31_cpu_type[i].srev)
+			return mx31_cpu_type[i].v;
+		return "unknown";
+}
+
 #if defined(CONFIG_DISPLAY_CPUINFO)
 int print_cpuinfo (void)
 {
-	printf("CPU:   Freescale i.MX31 at %d MHz\n",
-		mx31_get_mcu_main_clk() / 1000000);
+	printf("CPU:   Freescale i.MX31 rev %s at %d MHz\n",
+			get_cpu_rev(), mx31_get_mcu_main_clk() / 1000000);
 	return 0;
 }
 #endif

arch/arm/include/asm/arch-mx31/imx-regs.h

@@ -84,6 +84,29 @@ struct wdog_regs {
 	u16 wrsr;	/* Reset Status */
 };
 
+/* IIM Control Registers */
+struct iim_regs {
+	u32 iim_stat;
+	u32 iim_statm;
+	u32 iim_err;
+	u32 iim_emask;
+	u32 iim_fctl;
+	u32 iim_ua;
+	u32 iim_la;
+	u32 iim_sdat;
+	u32 iim_prev;
+	u32 iim_srev;
+	u32 iim_prog_p;
+	u32 iim_scs0;
+	u32 iim_scs1;
+	u32 iim_scs2;
+	u32 iim_scs3;
+};
+
+struct mx3_cpu_type {
+	u8 srev;
+	const char *v;
+};
 
 #define IOMUX_PADNUM_MASK	0x1ff
 #define IOMUX_PIN(gpionum, padnum) ((padnum) & IOMUX_PADNUM_MASK)
@@ -480,6 +503,8 @@ enum iomux_pins {
 #define CCMR_FPM	(1 << 1)
 #define CCMR_CKIH	(2 << 1)
 
+#define MX31_IIM_BASE_ADDR	0x5001C000
+
 #define PDR0_CSI_PODF(x)	(((x) & 0x1ff) << 23)
 #define PDR0_PER_PODF(x)	(((x) & 0x1f) << 16)
 #define PDR0_HSP_PODF(x)	(((x) & 0x7) << 11)