mx51evk: Add CONFIG_REVISION_TAG

FSL 2.6.35 kernel assumes that the bootloader passes the CONFIG_REVISION_TAG
information.

If this data is not present, the kernel misconfigures the TZIC, which results in
the timer interrupt handler never being called, so the kernel deadlocks while
calibrating its delay.

Suggested-by: Greg Topmiller <Greg.Topmiller@jdsu.com>
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Acked-by: Fabio Estevam <fabio.estevam@freescale.com>

arch/arm/include/asm/arch-mx5/imx-regs.h

@@ -315,6 +315,8 @@
 #define BOARD_REV_1_0           0x0
 #define BOARD_REV_2_0           0x1
 
+#define BOARD_VER_OFFSET	0x8
+
 #define IMX_IIM_BASE            (IIM_BASE_ADDR)
 
 #if !(defined(__KERNEL_STRICT_NAMES) || defined(__ASSEMBLY__))

board/freescale/mx51evk/mx51evk.c

@@ -54,6 +54,14 @@ int dram_init(void)
 	return 0;
 }
 
+u32 get_board_rev(void)
+{
+	u32 rev = get_cpu_rev();
+	if (!gpio_get_value(IMX_GPIO_NR(1, 22)))
+		rev |= BOARD_REV_2_0 << BOARD_VER_OFFSET;
+	return rev;
+}
+
 static void setup_iomux_uart(void)
 {
 	unsigned int pad = PAD_CTL_HYS_ENABLE | PAD_CTL_PKE_ENABLE |

include/configs/mx51evk.h

@@ -44,6 +44,7 @@
 #define CONFIG_CMDLINE_TAG			/* enable passing of ATAGs */
 #define CONFIG_SETUP_MEMORY_TAGS
 #define CONFIG_INITRD_TAG
+#define CONFIG_REVISION_TAG
 
 #define CONFIG_OF_LIBFDT