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MIPS: Fix CM region target definitions
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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 9f98f3d ("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 39b8d52 ("[MIPS] Add support for MIPS CMP platform.") in the
v2.6.26 cycle.

Fixes: 9f98f3d ("MIPS: Add generic CM probe & access code")
Signed-off-by: Paul Burton <[email protected]>
Reported-by: Matt Redfearn <[email protected]>
Reviewed-by: James Hogan <[email protected]>
Cc: Matt Redfearn <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: [email protected]
Cc: <[email protected]> # v3.15+
Patchwork: https://patchwork.linux-mips.org/patch/17562/
Signed-off-by: James Hogan <[email protected]>
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paulburton authored and amalon committed Oct 31, 2017
1 parent 7f005f1 commit 6a6cba1
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions arch/mips/include/asm/mips-cm.h
Original file line number Diff line number Diff line change
Expand Up @@ -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

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