[CELL] spufs: Avoid unexpectedly restaring MFC during context save

The current SPU context saving procedure in SPUFS unexpectedly
restarts MFC when halting decrementer, because MFC_CNTL[Dh] is set
without MFC_CNTL[Sm]. This bug causes, for example, saving broken DMA
queues. Here is a patch to fix the problem.

Signed-off-by: Kazunori Asayama <asayama@sm.sony.co.jp>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

2 files changed, 3 insertions, 1 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/switch.c b/arch/powerpc/platforms/cell/spufs/switch.c
index 9c506ba08cdc..827aada391f2 100644
--- a/arch/powerpc/platforms/cell/spufs/switch.c
+++ b/arch/powerpc/platforms/cell/spufs/switch.c
@@ -271,7 +271,8 @@ static inline void halt_mfc_decr(struct spu_state *csa, struct spu *spu)
          *     Write MFC_CNTL[Dh] set to a '1' to halt
          *     the decrementer.
          */
-        out_be64(&priv2->mfc_control_RW, MFC_CNTL_DECREMENTER_HALTED);
+        out_be64(&priv2->mfc_control_RW,
+                 MFC_CNTL_DECREMENTER_HALTED | MFC_CNTL_SUSPEND_MASK);
         eieio();
 }
 
diff --git a/include/asm-powerpc/spu.h b/include/asm-powerpc/spu.h
index 42d88a6d2dfd..a034f03b8107 100644
--- a/include/asm-powerpc/spu.h
+++ b/include/asm-powerpc/spu.h
@@ -411,6 +411,7 @@ struct spu_priv2 {
 #define MFC_CNTL_RESUME_DMA_QUEUE               (0ull << 0)
 #define MFC_CNTL_SUSPEND_DMA_QUEUE              (1ull << 0)
 #define MFC_CNTL_SUSPEND_DMA_QUEUE_MASK         (1ull << 0)
+#define MFC_CNTL_SUSPEND_MASK                   (1ull << 4)
 #define MFC_CNTL_NORMAL_DMA_QUEUE_OPERATION     (0ull << 8)
 #define MFC_CNTL_SUSPEND_IN_PROGRESS            (1ull << 8)
 #define MFC_CNTL_SUSPEND_COMPLETE               (3ull << 8)