drm: omapdrm: Handle FIFO underflow IRQs internally

As the FIFO underflow IRQ handler just prints an error message to the
kernel log, simplify the code by not registering one IRQ handler per
plane but print the messages directly from the main IRQ handler.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/omap_drv.c

@@ -315,8 +315,6 @@ static int omap_modeset_init(struct drm_device *dev)
 
 	drm_mode_config_init(dev);
 
-	omap_drm_irq_install(dev);
-
 	ret = omap_modeset_init_properties(dev);
 	if (ret < 0)
 		return ret;
@@ -489,6 +487,8 @@ static int omap_modeset_init(struct drm_device *dev)
 
 	drm_mode_config_reset(dev);
 
+	omap_drm_irq_install(dev);
+
 	return 0;
 }
 

drivers/gpu/drm/omapdrm/omap_drv.h

@@ -102,7 +102,7 @@ struct omap_drm_private {
 
 	/* irq handling: */
 	struct list_head irq_list;    /* list of omap_drm_irq */
-	uint32_t vblank_mask;         /* irq bits set for userspace vblank */
+	uint32_t irq_mask;		/* enabled irqs in addition to irq_list */
 	struct omap_drm_irq error_handler;
 
 	/* atomic commit */

drivers/gpu/drm/omapdrm/omap_irq.c

@@ -32,7 +32,7 @@ static void omap_irq_update(struct drm_device *dev)
 {
 	struct omap_drm_private *priv = dev->dev_private;
 	struct omap_drm_irq *irq;
-	uint32_t irqmask = priv->vblank_mask;
+	uint32_t irqmask = priv->irq_mask;
 
 	assert_spin_locked(&list_lock);
 
@@ -153,7 +153,7 @@ int omap_irq_enable_vblank(struct drm_device *dev, unsigned int pipe)
 	DBG("dev=%p, crtc=%u", dev, pipe);
 
 	spin_lock_irqsave(&list_lock, flags);
-	priv->vblank_mask |= pipe2vbl(crtc);
+	priv->irq_mask |= pipe2vbl(crtc);
 	omap_irq_update(dev);
 	spin_unlock_irqrestore(&list_lock, flags);
 
@@ -178,11 +178,52 @@ void omap_irq_disable_vblank(struct drm_device *dev, unsigned int pipe)
 	DBG("dev=%p, crtc=%u", dev, pipe);
 
 	spin_lock_irqsave(&list_lock, flags);
-	priv->vblank_mask &= ~pipe2vbl(crtc);
+	priv->irq_mask &= ~pipe2vbl(crtc);
 	omap_irq_update(dev);
 	spin_unlock_irqrestore(&list_lock, flags);
 }
 
+static void omap_irq_fifo_underflow(struct omap_drm_private *priv,
+				    u32 irqstatus)
+{
+	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
+				      DEFAULT_RATELIMIT_BURST);
+	static const struct {
+		const char *name;
+		u32 mask;
+	} sources[] = {
+		{ "gfx", DISPC_IRQ_GFX_FIFO_UNDERFLOW },
+		{ "vid1", DISPC_IRQ_VID1_FIFO_UNDERFLOW },
+		{ "vid2", DISPC_IRQ_VID2_FIFO_UNDERFLOW },
+		{ "vid3", DISPC_IRQ_VID3_FIFO_UNDERFLOW },
+	};
+
+	const u32 mask = DISPC_IRQ_GFX_FIFO_UNDERFLOW
+		       | DISPC_IRQ_VID1_FIFO_UNDERFLOW
+		       | DISPC_IRQ_VID2_FIFO_UNDERFLOW
+		       | DISPC_IRQ_VID3_FIFO_UNDERFLOW;
+	unsigned int i;
+
+	spin_lock(&list_lock);
+	irqstatus &= priv->irq_mask & mask;
+	spin_unlock(&list_lock);
+
+	if (!irqstatus)
+		return;
+
+	if (!__ratelimit(&_rs))
+		return;
+
+	DRM_ERROR("FIFO underflow on ");
+
+	for (i = 0; i < ARRAY_SIZE(sources); ++i) {
+		if (sources[i].mask & irqstatus)
+			pr_cont("%s ", sources[i].name);
+	}
+
+	pr_cont("(0x%08x)\n", irqstatus);
+}
+
 static irqreturn_t omap_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
@@ -205,6 +246,8 @@ static irqreturn_t omap_irq_handler(int irq, void *arg)
 			drm_handle_vblank(dev, id);
 	}
 
+	omap_irq_fifo_underflow(priv, irqstatus);
+
 	spin_lock_irqsave(&list_lock, flags);
 	list_for_each_entry_safe(handler, n, &priv->irq_list, node) {
 		if (handler->irqmask & irqstatus) {
@@ -218,6 +261,13 @@ static irqreturn_t omap_irq_handler(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static const u32 omap_underflow_irqs[] = {
+	[OMAP_DSS_GFX] = DISPC_IRQ_GFX_FIFO_UNDERFLOW,
+	[OMAP_DSS_VIDEO1] = DISPC_IRQ_VID1_FIFO_UNDERFLOW,
+	[OMAP_DSS_VIDEO2] = DISPC_IRQ_VID2_FIFO_UNDERFLOW,
+	[OMAP_DSS_VIDEO3] = DISPC_IRQ_VID3_FIFO_UNDERFLOW,
+};
+
 /*
  * We need a special version, instead of just using drm_irq_install(),
  * because we need to register the irq via omapdss.  Once omapdss and
@@ -229,10 +279,21 @@ int omap_drm_irq_install(struct drm_device *dev)
 {
 	struct omap_drm_private *priv = dev->dev_private;
 	struct omap_drm_irq *error_handler = &priv->error_handler;
+	unsigned int max_planes;
+	unsigned int i;
 	int ret;
 
 	INIT_LIST_HEAD(&priv->irq_list);
 
+	priv->irq_mask = 0;
+
+	max_planes = min(ARRAY_SIZE(priv->planes),
+			 ARRAY_SIZE(omap_underflow_irqs));
+	for (i = 0; i < max_planes; ++i) {
+		if (priv->planes[i])
+			priv->irq_mask |= omap_underflow_irqs[i];
+	}
+
 	dispc_runtime_get();
 	dispc_clear_irqstatus(0xffffffff);
 	dispc_runtime_put();

drivers/gpu/drm/omapdrm/omap_plane.c

@@ -43,8 +43,6 @@ struct omap_plane {
 
 	uint32_t nformats;
 	uint32_t formats[32];
-
-	struct omap_drm_irq error_irq;
 };
 
 struct omap_plane_state {
@@ -204,8 +202,6 @@ static void omap_plane_destroy(struct drm_plane *plane)
 
 	DBG("%s", omap_plane->name);
 
-	omap_irq_unregister(plane->dev, &omap_plane->error_irq);
-
 	drm_plane_cleanup(plane);
 
 	kfree(omap_plane);
@@ -332,14 +328,6 @@ static const struct drm_plane_funcs omap_plane_funcs = {
 	.atomic_get_property = omap_plane_atomic_get_property,
 };
 
-static void omap_plane_error_irq(struct omap_drm_irq *irq, uint32_t irqstatus)
-{
-	struct omap_plane *omap_plane =
-			container_of(irq, struct omap_plane, error_irq);
-	DRM_ERROR_RATELIMITED("%s: errors: %08x\n", omap_plane->name,
-		irqstatus);
-}
-
 static const char *plane_names[] = {
 	[OMAP_DSS_GFX] = "gfx",
 	[OMAP_DSS_VIDEO1] = "vid1",
@@ -347,13 +335,6 @@ static const char *plane_names[] = {
 	[OMAP_DSS_VIDEO3] = "vid3",
 };
 
-static const uint32_t error_irqs[] = {
-	[OMAP_DSS_GFX] = DISPC_IRQ_GFX_FIFO_UNDERFLOW,
-	[OMAP_DSS_VIDEO1] = DISPC_IRQ_VID1_FIFO_UNDERFLOW,
-	[OMAP_DSS_VIDEO2] = DISPC_IRQ_VID2_FIFO_UNDERFLOW,
-	[OMAP_DSS_VIDEO3] = DISPC_IRQ_VID3_FIFO_UNDERFLOW,
-};
-
 /* initialize plane */
 struct drm_plane *omap_plane_init(struct drm_device *dev,
 		int id, enum drm_plane_type type,
@@ -377,10 +358,6 @@ struct drm_plane *omap_plane_init(struct drm_device *dev,
 
 	plane = &omap_plane->base;
 
-	omap_plane->error_irq.irqmask = error_irqs[id];
-	omap_plane->error_irq.irq = omap_plane_error_irq;
-	omap_irq_register(dev, &omap_plane->error_irq);
-
 	ret = drm_universal_plane_init(dev, plane, possible_crtcs,
 				       &omap_plane_funcs, omap_plane->formats,
 				       omap_plane->nformats, type, NULL);
@@ -394,7 +371,6 @@ struct drm_plane *omap_plane_init(struct drm_device *dev,
 	return plane;
 
 error:
-	omap_irq_unregister(plane->dev, &omap_plane->error_irq);
 	kfree(omap_plane);
 	return NULL;
 }