drm: omapdrm: Simplify IRQ registration

The omapdrm can't use drm_irq_install() and drm_irq_uninstall() as it
delegates IRQ handling to the omapdss driver. However, the code still
declares IRQ-related operations used by the DRM IRQ helpers, and calls
them indirectly.

Simplify the implementation by calling the functions directly or
inlining them. The irq_enabled checks can then also be simplified as
the call stacks guarantees that omap_drm_irq_install() and
omap_drm_irq_uninstall() will never run concurrently.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/omap_irq.c b/drivers/gpu/drm/omapdrm/omap_irq.c
index 3eb097e..803aff0 100644
--- a/drivers/gpu/drm/omapdrm/omap_irq.c
+++ b/drivers/gpu/drm/omapdrm/omap_irq.c
@@ -187,7 +187,7 @@
 	dispc_runtime_put();
 }
 
-irqreturn_t omap_irq_handler(int irq, void *arg)
+static irqreturn_t omap_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *) arg;
 	struct omap_drm_private *priv = dev->dev_private;
@@ -222,23 +222,29 @@
 	return IRQ_HANDLED;
 }
 
-void omap_irq_preinstall(struct drm_device *dev)
-{
-	DBG("dev=%p", dev);
-	dispc_runtime_get();
-	dispc_clear_irqstatus(0xffffffff);
-	dispc_runtime_put();
-}
+/*
+ * We need a special version, instead of just using drm_irq_install(),
+ * because we need to register the irq via omapdss.  Once omapdss and
+ * omapdrm are merged together we can assign the dispc hwmod data to
+ * ourselves and drop these and just use drm_irq_{install,uninstall}()
+ */
 
-int omap_irq_postinstall(struct drm_device *dev)
+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;
-
-	DBG("dev=%p", dev);
+	int ret;
 
 	INIT_LIST_HEAD(&priv->irq_list);
 
+	dispc_runtime_get();
+	dispc_clear_irqstatus(0xffffffff);
+	dispc_runtime_put();
+
+	ret = dispc_request_irq(omap_irq_handler, dev);
+	if (ret < 0)
+		return ret;
+
 	error_handler->irq = omap_irq_error_handler;
 	error_handler->irqmask = DISPC_IRQ_OCP_ERR;
 
@@ -249,76 +255,22 @@
 
 	omap_irq_register(dev, error_handler);
 
+	dev->irq_enabled = true;
+
 	return 0;
 }
 
-void omap_irq_uninstall(struct drm_device *dev)
-{
-	DBG("dev=%p", dev);
-	// TODO prolly need to call drm_irq_uninstall() somewhere too
-}
-
-/*
- * We need a special version, instead of just using drm_irq_install(),
- * because we need to register the irq via omapdss.  Once omapdss and
- * omapdrm are merged together we can assign the dispc hwmod data to
- * ourselves and drop these and just use drm_irq_{install,uninstall}()
- */
-
-int omap_drm_irq_install(struct drm_device *dev)
-{
-	int ret;
-
-	mutex_lock(&dev->struct_mutex);
-
-	if (dev->irq_enabled) {
-		mutex_unlock(&dev->struct_mutex);
-		return -EBUSY;
-	}
-	dev->irq_enabled = true;
-	mutex_unlock(&dev->struct_mutex);
-
-	/* Before installing handler */
-	if (dev->driver->irq_preinstall)
-		dev->driver->irq_preinstall(dev);
-
-	ret = dispc_request_irq(dev->driver->irq_handler, dev);
-
-	if (ret < 0) {
-		mutex_lock(&dev->struct_mutex);
-		dev->irq_enabled = false;
-		mutex_unlock(&dev->struct_mutex);
-		return ret;
-	}
-
-	/* After installing handler */
-	if (dev->driver->irq_postinstall)
-		ret = dev->driver->irq_postinstall(dev);
-
-	if (ret < 0) {
-		mutex_lock(&dev->struct_mutex);
-		dev->irq_enabled = false;
-		mutex_unlock(&dev->struct_mutex);
-		dispc_free_irq(dev);
-	}
-
-	return ret;
-}
-
-int omap_drm_irq_uninstall(struct drm_device *dev)
+void omap_drm_irq_uninstall(struct drm_device *dev)
 {
 	unsigned long irqflags;
-	bool irq_enabled;
 	int i;
 
-	mutex_lock(&dev->struct_mutex);
-	irq_enabled = dev->irq_enabled;
-	dev->irq_enabled = false;
-	mutex_unlock(&dev->struct_mutex);
+	if (!dev->irq_enabled)
+		return;
 
-	/*
-	 * Wake up any waiters so they don't hang.
-	 */
+	dev->irq_enabled = false;
+
+	/* Wake up any waiters so they don't hang. */
 	if (dev->num_crtcs) {
 		spin_lock_irqsave(&dev->vbl_lock, irqflags);
 		for (i = 0; i < dev->num_crtcs; i++) {
@@ -330,13 +282,5 @@
 		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 	}
 
-	if (!irq_enabled)
-		return -EINVAL;
-
-	if (dev->driver->irq_uninstall)
-		dev->driver->irq_uninstall(dev);
-
 	dispc_free_irq(dev);
-
-	return 0;
 }