tree a43d483cf144eb0f770a6e2e8ac9f721965a7fa9
parent 8085ce084c0f0144c353963853f81486fc331120
author Kumar Gala <[EMAIL PROTECTED]> Wed, 31 Aug 2005 14:54:47 +1000
committer Linus Torvalds <[EMAIL PROTECTED]> Fri, 02 Sep 2005 00:52:29 -0700
[PATCH] ppc: L2 cache prefetch fixes on 745x
We run into problems if we blindly enable L2 prefetching without
checking that the L2 cache is actually enabled. Additionaly, if we
disable the L2 cache we need to ensure that we disable L2 prefetching.
Signed-off-by: Kumar Gala <[EMAIL PROTECTED]>
Signed-off-by: Benjamin Herrenschmidt <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
arch/ppc/kernel/cpu_setup_6xx.S | 5 ++++-
arch/ppc/kernel/l2cr.S | 31 ++++++++++++++++++++++++++++++-
2 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/arch/ppc/kernel/cpu_setup_6xx.S b/arch/ppc/kernel/cpu_setup_6xx.S
--- a/arch/ppc/kernel/cpu_setup_6xx.S
+++ b/arch/ppc/kernel/cpu_setup_6xx.S
@@ -249,8 +249,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_NO_DPM)
sync
isync
- /* Enable L2 HW prefetch
+ /* Enable L2 HW prefetch, if L2 is enabled
*/
+ mfspr r3,SPRN_L2CR
+ andis. r3,r3,[EMAIL PROTECTED]
+ beqlr
mfspr r3,SPRN_MSSCR0
ori r3,r3,3
sync
diff --git a/arch/ppc/kernel/l2cr.S b/arch/ppc/kernel/l2cr.S
--- a/arch/ppc/kernel/l2cr.S
+++ b/arch/ppc/kernel/l2cr.S
@@ -156,6 +156,26 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
The bit moved on the 7450.....
****/
+BEGIN_FTR_SECTION
+ /* Disable L2 prefetch on some 745x and try to ensure
+ * L2 prefetch engines are idle. As explained by errata
+ * text, we can't be sure they are, we just hope very hard
+ * that well be enough (sic !). At least I noticed Apple
+ * doesn't even bother doing the dcbf's here...
+ */
+ mfspr r4,SPRN_MSSCR0
+ rlwinm r4,r4,0,0,29
+ sync
+ mtspr SPRN_MSSCR0,r4
+ sync
+ isync
+ lis r4,[EMAIL PROTECTED]
+ dcbf 0,r4
+ dcbf 0,r4
+ dcbf 0,r4
+ dcbf 0,r4
+END_FTR_SECTION_IFSET(CPU_FTR_SPEC7450)
+
/* TODO: use HW flush assist when available */
lis r4,0x0002
@@ -230,7 +250,16 @@ END_FTR_SECTION_IFSET(CPU_FTR_SPEC7450)
oris r3,r3,0x8000
mtspr SPRN_L2CR,r3
sync
-
+
+ /* Enable L2 HW prefetch on 744x/745x */
+BEGIN_FTR_SECTION
+ mfspr r3,SPRN_MSSCR0
+ ori r3,r3,3
+ sync
+ mtspr SPRN_MSSCR0,r3
+ sync
+ isync
+END_FTR_SECTION_IFSET(CPU_FTR_SPEC7450)
4:
/* Restore HID0[DPM] to whatever it was before */
-
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