powerpc/spufs: wait for stable spu status in spu_stopped()

If the spu is stopping (ie, the SPU_STATUS_RUNNING bit is still set),
re-read the register to get the final stopped value.

Signed-off-by: Luke Browning <lukebrowning@us.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

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

@@ -51,14 +51,22 @@ int spu_stopped(struct spu_context *ctx, u32 *stat)
 	u64 dsisr;
 	u32 stopped;
 
-	*stat = ctx->ops->status_read(ctx);
+	stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
+		SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
 
-	if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
+top:
+	*stat = ctx->ops->status_read(ctx);
+	if (*stat & stopped) {
+		/*
+		 * If the spu hasn't finished stopping, we need to
+		 * re-read the register to get the stopped value.
+		 */
+		if (*stat & SPU_STATUS_RUNNING)
+			goto top;
 		return 1;
+	}
 
-	stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
-		SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
-	if (!(*stat & SPU_STATUS_RUNNING) && (*stat & stopped))
+	if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
 		return 1;
 
 	dsisr = ctx->csa.class_0_dsisr;