On Tue, Oct 31, 2017 at 03:09:22PM -0700, Paul Burton wrote:
> 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+
Reviewed-by: James Hogan <jhogan@xxxxxxxxxx>
Cheers
James
> ---
>
> 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
>
>
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