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authorDavid Gibson <david@gibson.dropbear.id.au>2007-06-13 14:52:57 +1000
committerPaul Mackerras <paulus@samba.org>2007-06-14 22:30:16 +1000
commit4508dc21feb189159d4cc1d5b79c5a55fad5f2ed (patch)
tree8128d7642606a64e2b65a4ea9d2e74cf70cdf1f8 /arch/powerpc/kernel
parent8e561e7eda02819c711a75b64a000bf34948cdbb (diff)
[POWERPC] Merge CPU features pertaining to icache coherency
Currently the powerpc kernel has a 64-bit only feature, COHERENT_ICACHE used for those CPUS which maintain icache/dcache coherency in hardware (POWER5, essentially). It also has a feature, SPLIT_ID_CACHE, which is used on CPUs which have separate i and d-caches, which is to say everything except 601 and Freescale E200. In nearly all the places we check the SPLIT_ID_CACHE, what we actually care about is whether the i and d-caches are coherent (which they will be, trivially, if they're the same cache). This tries to clarify the situation a little. The COHERENT_ICACHE feature becomes availble on 32-bit and is set for all CPUs where i and d-cache are effectively coherent, whether this is due to special logic (POWER5) or because they're unified. We check this, instead of SPLIT_ID_CACHE nearly everywhere. The SPLIT_ID_CACHE feature itself is replaced by a UNIFIED_ID_CACHE feature with reversed sense, set only on 601 and Freescale E200. In the two places (one Freescale BookE specific) where we really care whether it's a unified cache, not whether they're coherent, we check this feature. The CPUs with unified cache are so few, we could consider replacing this feature bit with explicit checks against the PVR. This will make unifying the 32-bit and 64-bit cache flush code a little more straightforward. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/misc_32.S10
-rw-r--r--arch/powerpc/kernel/setup_32.c12
2 files changed, 10 insertions, 12 deletions
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 98decf8ebff..e708ab7ca9e 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -392,7 +392,7 @@ BEGIN_FTR_SECTION
mtspr SPRN_L1CSR0,r3
isync
blr
-END_FTR_SECTION_IFCLR(CPU_FTR_SPLIT_ID_CACHE)
+END_FTR_SECTION_IFSET(CPU_FTR_UNIFIED_ID_CACHE)
mfspr r3,SPRN_L1CSR1
ori r3,r3,L1CSR1_ICFI|L1CSR1_ICLFR
mtspr SPRN_L1CSR1,r3
@@ -419,7 +419,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SPLIT_ID_CACHE)
_GLOBAL(__flush_icache_range)
BEGIN_FTR_SECTION
blr /* for 601, do nothing */
-END_FTR_SECTION_IFCLR(CPU_FTR_SPLIT_ID_CACHE)
+END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
li r5,L1_CACHE_BYTES-1
andc r3,r3,r5
subf r4,r3,r4
@@ -514,8 +514,8 @@ _GLOBAL(invalidate_dcache_range)
*/
_GLOBAL(__flush_dcache_icache)
BEGIN_FTR_SECTION
- blr /* for 601, do nothing */
-END_FTR_SECTION_IFCLR(CPU_FTR_SPLIT_ID_CACHE)
+ blr
+END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
rlwinm r3,r3,0,0,19 /* Get page base address */
li r4,4096/L1_CACHE_BYTES /* Number of lines in a page */
mtctr r4
@@ -543,7 +543,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_SPLIT_ID_CACHE)
_GLOBAL(__flush_dcache_icache_phys)
BEGIN_FTR_SECTION
blr /* for 601, do nothing */
-END_FTR_SECTION_IFCLR(CPU_FTR_SPLIT_ID_CACHE)
+END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
mfmsr r10
rlwinm r0,r10,0,28,26 /* clear DR */
mtmsr r0
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 35f8f443c14..7ec6ba56d83 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -262,13 +262,11 @@ void __init setup_arch(char **cmdline_p)
* Systems with OF can look in the properties on the cpu node(s)
* for a possibly more accurate value.
*/
- if (cpu_has_feature(CPU_FTR_SPLIT_ID_CACHE)) {
- dcache_bsize = cur_cpu_spec->dcache_bsize;
- icache_bsize = cur_cpu_spec->icache_bsize;
- ucache_bsize = 0;
- } else
- ucache_bsize = dcache_bsize = icache_bsize
- = cur_cpu_spec->dcache_bsize;
+ dcache_bsize = cur_cpu_spec->dcache_bsize;
+ icache_bsize = cur_cpu_spec->icache_bsize;
+ ucache_bsize = 0;
+ if (cpu_has_feature(CPU_FTR_UNIFIED_ID_CACHE))
+ ucache_bsize = icache_bsize = dcache_bsize;
/* reboot on panic */
panic_timeout = 180;