[U-Boot] [PATCH 02/15] Store existing atags at startup if chainloading.

[Pali Rohár]

From: Alistair Buxton <a.j.buxton at gmail.com>

This patch stores the values in r1 and r2 at startup. It also stores the address
which u-boot was originally loaded to. This is useful if you feed some other
bootloader a u-boot.bin instead of the linux kernel it was expecting. It is
rather ugly because it stores these values in an arbitrary memory address.

Signed-off-by: Alistair Buxton <a.j.buxton at gmail.com>
---
 arch/arm/cpu/armv7/start.S |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index db8e9d2..8a456f0 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -134,6 +134,22 @@ IRQ_STACK_START_IN:
  */
 
 reset:
+#if (CONFIG_CHAINLOADER)
+	/*
+	 * Ugly hack: store the u-boot load address and kernel params
+	 * 0x82000004: address where this image was loaded
+	 * 0x82000008: mach_type
+	 * 0x8200000c: atags address
+	 */
+	adr 	r0, _start
+	mov 	r3, #0x82000000
+	add	r3, r3, #4
+	str	r0, [r3]
+	add	r3, r3, #4
+	str	r1, [r3]
+	add	r3, r3, #4
+	str	r2, [r3]
+#endif
 	bl	save_boot_params
 	/*
 	 * set the cpu to SVC32 mode
-- 
1.7.4.1