[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>

2 files changed, 5 insertions, 5 deletions

diff --git a/arch/ppc/kernel/misc.S b/arch/ppc/kernel/misc.S
index d319f9ba2379..0da55368655c 100644
--- a/arch/ppc/kernel/misc.S
+++ b/arch/ppc/kernel/misc.S
@@ -328,7 +328,7 @@ 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
@@ -355,7 +355,7 @@ 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
@@ -472,7 +472,7 @@ _GLOBAL(flush_dcache_all)
 _GLOBAL(__flush_dcache_icache)
 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)
         rlwinm  r3,r3,0,0,19                    /* Get page base address */
         li      r4,4096/L1_CACHE_BYTES  /* Number of lines in a page */
         mtctr   r4
@@ -500,7 +500,7 @@ 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/ppc/kernel/setup.c b/arch/ppc/kernel/setup.c
index c79704f5409c..967c1ef59a6b 100644
--- a/arch/ppc/kernel/setup.c
+++ b/arch/ppc/kernel/setup.c
@@ -526,7 +526,7 @@ 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)) {
+        if (! cpu_has_feature(CPU_FTR_UNIFIED_ID_CACHE)) {
                 dcache_bsize = cur_cpu_spec->dcache_bsize;
                 icache_bsize = cur_cpu_spec->icache_bsize;
                 ucache_bsize = 0;