The default CM target field in the GCR_BASE register is encoded with 0
meaning memory & 1 being reserved. However the definitions we use for
those bits effectively get these two values backwards - likely because
they were copied from the definitions for the CM regions where the
target is encoded differently. This results in use setting up GCR_BASE
with the reserved target value by default, rather than targeting memory
as intended. Although we currently seem to get away with this it's not a
great idea to rely upon.
Fix this by changing our macros to match the documentated target values.
The incorrect encoding became used as of commit 9f98f3dd0c51 ("MIPS: Add
generic CM probe & access code") in the Linux v3.15 cycle, and was
likely carried forwards from older but unused code introduced by
commit 39b8d5254246 ("[MIPS] Add support for MIPS CMP platform.") in the
v2.6.26 cycle.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
Reported-by: Matt Redfearn <matt.redfearn@xxxxxxxx>
Cc: Matt Redfearn <matt.redfearn@xxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx> # v3.15+
---
arch/mips/include/asm/mips-cm.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/mips/include/asm/mips-cm.h b/arch/mips/include/asm/mips-cm.h
index f6231b91b724..c6aaabd7cfd1 100644
--- a/arch/mips/include/asm/mips-cm.h
+++ b/arch/mips/include/asm/mips-cm.h
@@ -142,8 +142,8 @@ GCR_ACCESSOR_RO(64, 0x000, config)
GCR_ACCESSOR_RW(64, 0x008, base)
#define CM_GCR_BASE_GCRBASE GENMASK_ULL(47, 15)
#define CM_GCR_BASE_CMDEFTGT GENMASK(1, 0)
-#define CM_GCR_BASE_CMDEFTGT_DISABLED 0
-#define CM_GCR_BASE_CMDEFTGT_MEM 1
+#define CM_GCR_BASE_CMDEFTGT_MEM 0
+#define CM_GCR_BASE_CMDEFTGT_RESERVED 1
#define CM_GCR_BASE_CMDEFTGT_IOCU0 2
#define CM_GCR_BASE_CMDEFTGT_IOCU1 3
--
2.15.0