[POWERPC] spufs: fix MFC command queue purge

In the context save/restore code, the SPU MFC command queue purge
code has a bug:

static inline void wait_purge_complete(struct spu_state *csa, struct
				       spu *spu)
{
    struct spu_priv2 __iomem *priv2 = spu->priv2;

    /* Save, Step 28:
     *     Poll MFC_CNTL[Ps] until value '11' is
     *     read
     *      (purge complete).
     */
    POLL_WHILE_FALSE(in_be64(&priv2->mfc_control_RW)
		     & MFC_CNTL_PURGE_DMA_COMPLETE);
}

This will exit as soon as _one_ of the 2 bits that compose
MFC_CNTL_PURGE_DMA_COMPLETE is set, and one of them happens to be
"purge in progress"...  which means that we'll happily continue
restoring the MFC while it's being purged at the same time.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/arch/powerpc/platforms/cell/spufs/switch.c b/arch/powerpc/platforms/cell/spufs/switch.c
index 3068b429b031149ce8e4a4741bd9a29a3f52c1ec..015a51787009dc360343ab1378a35dceb70d8a55 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/switch.c
+++ b/arch/powerpc/platforms/cell/spufs/switch.c
@@ -464,7 +464,8 @@ static inline void wait_purge_complete(struct spu_state *csa, struct spu *spu)
         *     Poll MFC_CNTL[Ps] until value '11' is read
         *     (purge complete).
         */
-       POLL_WHILE_FALSE(in_be64(&priv2->mfc_control_RW) &
+       POLL_WHILE_FALSE((in_be64(&priv2->mfc_control_RW) &
+                        MFC_CNTL_PURGE_DMA_STATUS_MASK) ==
                         MFC_CNTL_PURGE_DMA_COMPLETE);
 }
 
@@ -1028,7 +1029,8 @@ static inline void wait_suspend_mfc_complete(struct spu_state *csa,
         * Restore, Step 47.
         *     Poll MFC_CNTL[Ss] until 11 is returned.
         */
-       POLL_WHILE_FALSE(in_be64(&priv2->mfc_control_RW) &
+       POLL_WHILE_FALSE((in_be64(&priv2->mfc_control_RW) &
+                        MFC_CNTL_SUSPEND_DMA_STATUS_MASK) ==
                         MFC_CNTL_SUSPEND_COMPLETE);
 }