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, 26 insertions, 16 deletions

diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 4ea9bfbf67e9..e1c699f3b7a7 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -63,17 +63,30 @@ _ENTRY(_start);
          * of abatron_pteptrs
          */
         nop
-/*
- * Save parameters we are passed
- */
-        mr      r31,r3
-        mr      r30,r4
-        mr      r29,r5
-        mr      r28,r6
-        mr      r27,r7
-        li      r25,0           /* phys kernel start (low) */
-        li      r24,0           /* CPU number */
-        li      r23,0           /* phys kernel start (high) */
+
+        /* Translate device tree address to physical, save in r30/r31 */
+        mfmsr   r16
+        mfspr   r17,SPRN_PID
+        rlwinm  r17,r17,16,0x3fff0000   /* turn PID into MAS6[SPID] */
+        rlwimi  r17,r16,28,0x00000001   /* turn MSR[DS] into MAS6[SAS] */
+        mtspr   SPRN_MAS6,r17
+
+        tlbsx   0,r3                    /* must succeed */
+
+        mfspr   r16,SPRN_MAS1
+        mfspr   r20,SPRN_MAS3
+        rlwinm  r17,r16,25,0x1f         /* r17 = log2(page size) */
+        li      r18,1024
+        slw     r18,r18,r17             /* r18 = page size */
+        addi    r18,r18,-1
+        and     r19,r3,r18              /* r19 = page offset */
+        andc    r31,r20,r18             /* r3 = page base */
+        or      r31,r31,r19             /* r3 = devtree phys addr */
+        mfspr   r30,SPRN_MAS7
+
+        li      r25,0                   /* phys kernel start (low) */
+        li      r24,0                   /* CPU number */
+        li      r23,0                   /* phys kernel start (high) */
 
 /* We try to not make any assumptions about how the boot loader
  * setup or used the TLBs.  We invalidate all mappings from the
@@ -198,11 +211,8 @@ _ENTRY(__early_start)
 /*
  * 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
+        mr      r3,r30
+        mr      r4,r31
         bl      machine_init
         bl      MMU_init