Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d1dfc35d3a62122b85ca975b80dcbf4a0da0bebc
Commit: d1dfc35d3a62122b85ca975b80dcbf4a0da0bebc
Parent: 1d6b698764084510fe6168bb5b650165dced03ae
Author: Valentine Barshak <[EMAIL PROTECTED]>
AuthorDate: Fri Oct 26 04:16:40 2007 +1000
Committer: Josh Boyer <[EMAIL PROTECTED]>
CommitDate: Thu Nov 1 07:13:43 2007 -0500
[POWERPC] 4xx: Workaround for the 440EP(x)/GR(x) processors identical PVR
issue.
PowerPC 440EP(x) 440GR(x) processors have the same PVR values, since
they have identical cores. However, FPU is not supported on GR(x) and
enabling APU instruction broadcast in the CCR0 register (to enable FPU)
may cause unpredictable results. There's no safe way to detect FPU
support at runtime. This patch provides a workarund for the issue.
We use a POWER6 "logical PVR approach". First, we identify all EP(x)
and GR(x) processors as GR(x) ones (which is safe). Then we check
the device tree cpu path. If we have a EP(x) processor entry,
we call identify_cpu again with PVR | 0x8. This bit is always 0
in the real PVR. This way we enable FPU only for 440EP(x).
Signed-off-by: Valentine Barshak <[EMAIL PROTECTED]>
Signed-off-by: Josh Boyer <[EMAIL PROTECTED]>
---
arch/powerpc/kernel/cputable.c | 36 ++++++++++++++++++++++++++++--------
arch/powerpc/kernel/prom.c | 12 ++++++++++++
2 files changed, 40 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index d3fb7d0..9ed351f 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -1104,6 +1104,16 @@ static struct cpu_spec __initdata cpu_specs[] = {
{
.pvr_mask = 0xf0000fff,
.pvr_value = 0x40000850,
+ .cpu_name = "440GR Rev. A",
+ .cpu_features = CPU_FTRS_44X,
+ .cpu_user_features = COMMON_USER_BOOKE,
+ .icache_bsize = 32,
+ .dcache_bsize = 32,
+ .platform = "ppc440",
+ },
+ { /* Use logical PVR for 440EP (logical pvr = pvr | 0x8) */
+ .pvr_mask = 0xf0000fff,
+ .pvr_value = 0x40000858,
.cpu_name = "440EP Rev. A",
.cpu_features = CPU_FTRS_44X,
.cpu_user_features = COMMON_USER_BOOKE |
PPC_FEATURE_HAS_FPU,
@@ -1115,28 +1125,27 @@ static struct cpu_spec __initdata cpu_specs[] = {
{
.pvr_mask = 0xf0000fff,
.pvr_value = 0x400008d3,
- .cpu_name = "440EP Rev. B",
+ .cpu_name = "440GR Rev. B",
.cpu_features = CPU_FTRS_44X,
.cpu_user_features = COMMON_USER_BOOKE |
PPC_FEATURE_HAS_FPU,
.icache_bsize = 32,
.dcache_bsize = 32,
- .cpu_setup = __setup_cpu_440ep,
.platform = "ppc440",
},
- { /* 440EPX */
- .pvr_mask = 0xf0000ffb,
- .pvr_value = 0x200008D0,
- .cpu_name = "440EPX",
+ { /* Use logical PVR for 440EP (logical pvr = pvr | 0x8) */
+ .pvr_mask = 0xf0000fff,
+ .pvr_value = 0x400008db,
+ .cpu_name = "440EP Rev. B",
.cpu_features = CPU_FTRS_44X,
.cpu_user_features = COMMON_USER_BOOKE |
PPC_FEATURE_HAS_FPU,
.icache_bsize = 32,
.dcache_bsize = 32,
- .cpu_setup = __setup_cpu_440epx,
+ .cpu_setup = __setup_cpu_440ep,
.platform = "ppc440",
},
{ /* 440GRX */
.pvr_mask = 0xf0000ffb,
- .pvr_value = 0x200008D8,
+ .pvr_value = 0x200008D0,
.cpu_name = "440GRX",
.cpu_features = CPU_FTRS_44X,
.cpu_user_features = COMMON_USER_BOOKE,
@@ -1145,6 +1154,17 @@ static struct cpu_spec __initdata cpu_specs[] = {
.cpu_setup = __setup_cpu_440grx,
.platform = "ppc440",
},
+ { /* Use logical PVR for 440EPx (logical pvr = pvr | 0x8) */
+ .pvr_mask = 0xf0000ffb,
+ .pvr_value = 0x200008D8,
+ .cpu_name = "440EPX",
+ .cpu_features = CPU_FTRS_44X,
+ .cpu_user_features = COMMON_USER_BOOKE |
PPC_FEATURE_HAS_FPU,
+ .icache_bsize = 32,
+ .dcache_bsize = 32,
+ .cpu_setup = __setup_cpu_440epx,
+ .platform = "ppc440",
+ },
{ /* 440GP Rev. B */
.pvr_mask = 0xf0000fff,
.pvr_value = 0x40000440,
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 9f329a8..acc0d24 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -697,6 +697,18 @@ static int __init early_init_dt_scan_cpus(unsigned long
node,
prop = of_get_flat_dt_prop(node, "cpu-version", NULL);
if (prop && (*prop & 0xff000000) == 0x0f000000)
identify_cpu(0, *prop);
+#if defined(CONFIG_44x) && defined(CONFIG_PPC_FPU)
+ /*
+ * Since 440GR(x)/440EP(x) processors have the same pvr,
+ * we check the node path and set bit 28 in the cur_cpu_spec
+ * pvr for EP(x) processor version. This bit is always 0 in
+ * the "real" pvr. Then we call identify_cpu again with
+ * the new logical pvr to enable FPU support.
+ */
+ if (strstr(uname, "440EP")) {
+ identify_cpu(0, cur_cpu_spec->pvr_value | 0x8);
+ }
+#endif
}
check_cpu_feature_properties(node);
-
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