[ARM] 4423/1: add ATAGS support

Examines the ATAGS pointer (r2) at boot, and interprets
a nonzero value as a reference to an ATAGS structure. A
suitable ATAGS structure replaces the kernel's command line.

Signed-off-by: Bill Gatliff <bgat@billgatliff.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 1 deletions

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 41f98b4ba2ee..7898cbc9861a 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -29,6 +29,10 @@
 #define KERNEL_RAM_VADDR        (PAGE_OFFSET + TEXT_OFFSET)
 #define KERNEL_RAM_PADDR        (PHYS_OFFSET + TEXT_OFFSET)
 
+#define ATAG_CORE 0x54410001
+#define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2)
+
+
 /*
  * swapper_pg_dir is the virtual address of the initial page table.
  * We place the page tables 16K below KERNEL_RAM_VADDR.  Therefore, we must
@@ -61,7 +65,7 @@
  *
  * This is normally called from the decompressor code.  The requirements
  * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
- * r1 = machine nr.
+ * r1 = machine nr, r2 = atags pointer.
  *
  * This code is mostly position independent, so if you link the kernel at
  * 0xc0008000, you call this at __pa(0xc0008000).
@@ -85,6 +89,7 @@ ENTRY(stext)
         bl      __lookup_machine_type           @ r5=machinfo
         movs    r8, r5                          @ invalid machine (r5=0)?
         beq     __error_a                       @ yes, error 'a'
+        bl      __vet_atags
         bl      __create_page_tables
 
         /*