[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>

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();
 }
 

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)