[PATCH] ppc32: Workaround a cache flush issue on sleep

We are experiencing a problem when flushing the CPU caches before sleep
on some laptop models using the 750FX CPU rev 1.X. While I haven't been
able to figure out a proper explanation for what's going on, I do have a
workaround that seem to work reliably and allows those machine to sleep
and wakeup properly again.

I'll re-update that code if/when I ever find exactly what is happening
with those CPU revisions.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 42 insertions, 12 deletions

diff --git a/arch/ppc/platforms/pmac_cache.S b/arch/ppc/platforms/pmac_cache.S
index da34a9bc9299..fb977de6b704 100644
--- a/arch/ppc/platforms/pmac_cache.S
+++ b/arch/ppc/platforms/pmac_cache.S
@@ -64,27 +64,39 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
         mtspr   SPRN_HID0,r4            /* Disable DPM */
         sync
 
-        /* disp-flush L1 */
-        li      r4,0x4000
-        mtctr   r4
+        /* Disp-flush L1. We have a weird problem here that I never
+         * totally figured out. On 750FX, using the ROM for the flush
+         * results in a non-working flush. We use that workaround for
+         * now until I finally understand what's going on. --BenH
+         */
+
+        /* ROM base by default */
         lis     r4,0xfff0
-1:      lwzx    r0,r0,r4
+        mfpvr   r3
+        srwi    r3,r3,16
+        cmplwi  cr0,r3,0x7000
+        bne+    1f
+        /* RAM base on 750FX */
+        li      r4,0
+1:      li      r4,0x4000
+        mtctr   r4
+1:      lwz     r0,0(r4)
         addi    r4,r4,32
         bdnz    1b
         sync
         isync
 
-        /* disable / invalidate / enable L1 data */
+        /* Disable / invalidate / enable L1 data */
         mfspr   r3,SPRN_HID0
-        rlwinm  r0,r0,0,~HID0_DCE
+        rlwinm  r3,r3,0,~(HID0_DCE | HID0_ICE)
         mtspr   SPRN_HID0,r3
         sync
         isync
-        ori     r3,r3,HID0_DCE|HID0_DCI
+        ori     r3,r3,(HID0_DCE|HID0_DCI|HID0_ICE|HID0_ICFI)
         sync
         isync
         mtspr   SPRN_HID0,r3
-        xori    r3,r3,HID0_DCI
+        xori    r3,r3,(HID0_DCI|HID0_ICFI)
         mtspr   SPRN_HID0,r3
         sync
 
@@ -110,11 +122,20 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
         lis     r4,2
         mtctr   r4
         lis     r4,0xfff0
-1:      lwzx    r0,r0,r4
+1:      lwz     r0,0(r4)
+        addi    r4,r4,32
+        bdnz    1b
+        sync
+        isync
+        lis     r4,2
+        mtctr   r4
+        lis     r4,0xfff0
+1:      dcbf    0,r4
         addi    r4,r4,32
         bdnz    1b
         sync
         isync
+
         /* now disable L2 */
         rlwinm  r5,r5,0,~L2CR_L2E
         b       2f
@@ -135,6 +156,13 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
         mtspr   SPRN_L2CR,r4
         sync
         isync
+
+        /* Wait for the invalidation to complete */
+1:      mfspr   r3,SPRN_L2CR
+        rlwinm. r0,r3,0,31,31
+        bne     1b
+
+        /* Clear L2I */
         xoris   r4,r4,L2CR_L2I@h
         sync
         mtspr   SPRN_L2CR,r4
@@ -142,14 +170,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 
         /* now disable the L1 data cache */
         mfspr   r0,SPRN_HID0
-        rlwinm  r0,r0,0,~HID0_DCE
+        rlwinm  r0,r0,0,~(HID0_DCE|HID0_ICE)
         mtspr   SPRN_HID0,r0
         sync
         isync
 
         /* Restore HID0[DPM] to whatever it was before */
         sync
-        mtspr   SPRN_HID0,r8
+        mfspr   r0,SPRN_HID0
+        rlwimi  r0,r8,0,11,11           /* Turn back HID0[DPM] */
+        mtspr   SPRN_HID0,r0
         sync
 
         /* restore DR and EE */
@@ -201,7 +231,7 @@ flush_disable_745x:
         mtctr   r4
         li      r4,0
 1:
-        lwzx    r0,r0,r4
+        lwz     r0,0(r4)
         addi    r4,r4,32                /* Go to start of next cache line */
         bdnz    1b
         isync