powerpc/32: Pass device tree address as u64 to machine_init

u64 is used rather than phys_addr_t to keep things simple, as
this is called from assembly code.

Update callers to pass a 64-bit address in r3/r4.  Other unused
register assignments that were once parameters to machine_init
are dropped.

For FSL BookE, look up the physical address of the device tree from the
effective address passed in r3 by the loader.  This is required for
situations where memory does not start at zero (due to AMP or IOMMU-less
virtualization), and thus the IMA doesn't start at zero, and thus the
device tree effective address does not equal the physical address.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 3 insertions, 12 deletions

diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index a91626d87fc9..872a6af83bad 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -58,13 +58,7 @@
 _ENTRY(_stext);
 _ENTRY(_start);
 
-        /* Save parameters we are passed.
-        */
-        mr      r31,r3
-        mr      r30,r4
-        mr      r29,r5
-        mr      r28,r6
-        mr      r27,r7
+        mr      r31,r3                  /* save device tree ptr */
 
         /* We have to turn on the MMU right away so we get cache modes
          * set correctly.
@@ -849,11 +843,8 @@ start_here:
 /*
  * Decide what sort of machine this is and initialize the MMU.
  */
-        mr      r3,r31
-        mr      r4,r30
-        mr      r5,r29
-        mr      r6,r28
-        mr      r7,r27
+        li      r3,0
+        mr      r4,r31
         bl      machine_init
         bl      MMU_init