drm/nvc0-/disp: reimplement flip completion method as fifo method

Removes need for M2MF subchannel usage on NVC0+.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_display.c

@@ -438,15 +438,19 @@ nouveau_page_flip_emit(struct nouveau_channel *chan,
 		goto fail;
 
 	/* Emit the pageflip */
-	ret = RING_SPACE(chan, 2);
+	ret = RING_SPACE(chan, 3);
 	if (ret)
 		goto fail;
 
-	if (dev_priv->card_type < NV_C0)
+	if (dev_priv->card_type < NV_C0) {
 		BEGIN_RING(chan, NvSubSw, NV_SW_PAGE_FLIP, 1);
-	else
-		BEGIN_NVC0(chan, 2, NvSubM2MF, 0x0500, 1);
-	OUT_RING  (chan, 0);
+		OUT_RING  (chan, 0x00000000);
+		OUT_RING  (chan, 0x00000000);
+	} else {
+		BEGIN_NVC0(chan, 2, 0, NV10_SUBCHAN_REF_CNT, 1);
+		OUT_RING  (chan, ++chan->fence.sequence);
+		BEGIN_NVC0(chan, 8, 0, NVSW_SUBCHAN_PAGE_FLIP, 0x0000);
+	}
 	FIRE_RING (chan);
 
 	ret = nouveau_fence_new(chan, pfence, true);

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -1775,6 +1775,7 @@ nv44_graph_class(struct drm_device *dev)
 #define NV84_SUBCHAN_NOTIFY_INTR                                     0x00000020
 #define NV84_SUBCHAN_WRCACHE_FLUSH                                   0x00000024
 #define NV10_SUBCHAN_REF_CNT                                         0x00000050
+#define NVSW_SUBCHAN_PAGE_FLIP                                       0x00000054
 #define NV11_SUBCHAN_DMA_SEMAPHORE                                   0x00000060
 #define NV11_SUBCHAN_SEMAPHORE_OFFSET                                0x00000064
 #define NV11_SUBCHAN_SEMAPHORE_ACQUIRE                               0x00000068

drivers/gpu/drm/nouveau/nvc0_fifo.c

@@ -436,6 +436,24 @@ nvc0_fifo_isr_vm_fault(struct drm_device *dev, int unit)
 	printk(" on channel 0x%010llx\n", (u64)inst << 12);
 }
 
+static int
+nvc0_fifo_page_flip(struct drm_device *dev, u32 chid)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	struct nouveau_channel *chan = NULL;
+	unsigned long flags;
+	int ret = -EINVAL;
+
+	spin_lock_irqsave(&dev_priv->channels.lock, flags);
+	if (likely(chid >= 0 && chid < dev_priv->engine.fifo.channels)) {
+		chan = dev_priv->channels.ptr[chid];
+		if (likely(chan))
+			ret = nouveau_finish_page_flip(chan, NULL);
+	}
+	spin_unlock_irqrestore(&dev_priv->channels.lock, flags);
+	return ret;
+}
+
 static void
 nvc0_fifo_isr_subfifo_intr(struct drm_device *dev, int unit)
 {
@@ -445,11 +463,21 @@ nvc0_fifo_isr_subfifo_intr(struct drm_device *dev, int unit)
 	u32 chid = nv_rd32(dev, 0x040120 + (unit * 0x2000)) & 0x7f;
 	u32 subc = (addr & 0x00070000);
 	u32 mthd = (addr & 0x00003ffc);
+	u32 show = stat;
 
-	NV_INFO(dev, "PSUBFIFO %d:", unit);
-	nouveau_bitfield_print(nvc0_fifo_subfifo_intr, stat);
-	NV_INFO(dev, "PSUBFIFO %d: ch %d subc %d mthd 0x%04x data 0x%08x\n",
+	if (stat & 0x00200000) {
+		if (mthd == 0x0054) {
+			if (!nvc0_fifo_page_flip(dev, chid))
+				show &= ~0x00200000;
+		}
+	}
+
+	if (show) {
+		NV_INFO(dev, "PFIFO%d:", unit);
+		nouveau_bitfield_print(nvc0_fifo_subfifo_intr, show);
+		NV_INFO(dev, "PFIFO%d: ch %d subc %d mthd 0x%04x data 0x%08x\n",
 			     unit, chid, subc, mthd, data);
+	}
 
 	nv_wr32(dev, 0x0400c0 + (unit * 0x2000), 0x80600008);
 	nv_wr32(dev, 0x040108 + (unit * 0x2000), stat);

drivers/gpu/drm/nouveau/nvc0_graph.c

@@ -333,14 +333,6 @@ nvc0_graph_fini(struct drm_device *dev, int engine, bool suspend)
 	return 0;
 }
 
-static int
-nvc0_graph_mthd_page_flip(struct nouveau_channel *chan,
-			  u32 class, u32 mthd, u32 data)
-{
-	nouveau_finish_page_flip(chan, NULL);
-	return 0;
-}
-
 static void
 nvc0_graph_init_obj418880(struct drm_device *dev)
 {
@@ -889,7 +881,6 @@ nvc0_graph_create(struct drm_device *dev)
 
 	NVOBJ_CLASS(dev, 0x902d, GR); /* 2D */
 	NVOBJ_CLASS(dev, 0x9039, GR); /* M2MF */
-	NVOBJ_MTHD (dev, 0x9039, 0x0500, nvc0_graph_mthd_page_flip);
 	NVOBJ_CLASS(dev, 0x9097, GR); /* 3D */
 	if (fermi >= 0x9197)
 		NVOBJ_CLASS(dev, 0x9197, GR); /* 3D (NVC1-) */