[POWERPC] spufs: Save dma_tagstatus_R in CSA

The function backing_ops->read_mfc_tagstatus() doesn't return a
correct value because the dma_tagstatus_R register isn't saved in
CSA.  This fixes the problem.
Signed-off-by: Kazunori Asayama <asayama@sm.sony.co.jp>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/cell/spufs/backing_ops.c

@@ -320,6 +320,12 @@ static int spu_backing_set_mfc_query(struct spu_context * ctx, u32 mask,
 	/* FIXME: what are the side-effects of this? */
 	prob->dma_querymask_RW = mask;
 	prob->dma_querytype_RW = mode;
+	/* In the current implementation, the SPU context is always
+	 * acquired in runnable state when new bits are added to the
+	 * mask (tagwait), so it's sufficient just to mask
+	 * dma_tagstatus_R with the 'mask' parameter here.
+	 */
+	ctx->csa.prob.dma_tagstatus_R &= mask;
 out:
 	spin_unlock(&ctx->csa.register_lock);
 

arch/powerpc/platforms/cell/spufs/switch.c

@@ -387,6 +387,19 @@ static inline void save_ppu_querytype(struct spu_state *csa, struct spu *spu)
 	csa->prob.dma_querytype_RW = in_be32(&prob->dma_querytype_RW);
 }
 
+static inline void save_ppu_tagstatus(struct spu_state *csa, struct spu *spu)
+{
+	struct spu_problem __iomem *prob = spu->problem;
+
+	/* Save the Prxy_TagStatus register in the CSA.
+	 *
+	 * It is unnecessary to restore dma_tagstatus_R, however,
+	 * dma_tagstatus_R in the CSA is accessed via backing_ops, so
+	 * we must save it.
+	 */
+	csa->prob.dma_tagstatus_R = in_be32(&prob->dma_tagstatus_R);
+}
+
 static inline void save_mfc_csr_tsq(struct spu_state *csa, struct spu *spu)
 {
 	struct spu_priv2 __iomem *priv2 = spu->priv2;
@@ -1812,6 +1825,7 @@ static void save_csa(struct spu_state *prev, struct spu *spu)
 	save_mfc_queues(prev, spu);	/* Step 19. */
 	save_ppu_querymask(prev, spu);	/* Step 20. */
 	save_ppu_querytype(prev, spu);	/* Step 21. */
+	save_ppu_tagstatus(prev, spu);  /* NEW.     */
 	save_mfc_csr_tsq(prev, spu);	/* Step 22. */
 	save_mfc_csr_cmd(prev, spu);	/* Step 23. */
 	save_mfc_csr_ato(prev, spu);	/* Step 24. */