[POWERPC] bootwrapper: Add a firmware-independent simpleboot target.

This target produces a flat binary rather than an ELF file,
fixes the entry point at the beginning of the image, and takes
a complete device tree with no fixups needed.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/powerpc/boot/virtex405-head.S b/arch/powerpc/boot/virtex405-head.S
new file mode 100644
index 000000000000..3edb13f94669
--- /dev/null
+++ b/arch/powerpc/boot/virtex405-head.S
@@ -0,0 +1,30 @@
+#include "ppc_asm.h"
+
+        .text
+        .global _zimage_start
+_zimage_start:
+
+        /* PPC errata 213: needed by Virtex-4 FX */
+        mfccr0  0
+        oris    0,0,0x50000000@h
+        mtccr0  0
+
+        /*
+         * Invalidate the data cache if the data cache is turned off.
+         * - The 405 core does not invalidate the data cache on power-up
+         *   or reset but does turn off the data cache. We cannot assume
+         *   that the cache contents are valid.
+         * - If the data cache is turned on this must have been done by
+         *   a bootloader and we assume that the cache contents are
+         *   valid.
+         */
+        mfdccr  r9
+        cmplwi  r9,0
+        bne     2f
+        lis     r9,0
+        li      r8,256
+        mtctr   r8
+1:      dccci   r0,r9
+        addi    r9,r9,0x20
+        bdnz    1b
+2:      b       _zimage_start_lib