[PATCH 2/6] drm/vkms: Use vblank timer

[Thomas Zimmermann <tzimmermann@suse.de>]

Replace vkms' vblank timer with the DRM implementation. The DRM
code is mostly identical.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/vkms/vkms_crtc.c | 49 +++++++-------------------------
 drivers/gpu/drm/vkms/vkms_drv.h  |  6 ++--
 2 files changed, 15 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 8c9898b9055d..5b7829e8c900 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -10,22 +10,14 @@
 
 #include "vkms_drv.h"
 
-static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
+static bool vkms_crtc_handle_vblank(struct drm_crtc *crtc)
 {
-	struct vkms_output *output = container_of(timer, struct vkms_output,
-						  vblank_hrtimer);
-	struct drm_crtc *crtc = &output->crtc;
+	struct vkms_output *output = drm_crtc_to_vkms_output(crtc);
 	struct vkms_crtc_state *state;
-	u64 ret_overrun;
 	bool ret, fence_cookie;
 
 	fence_cookie = dma_fence_begin_signalling();
 
-	ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
-					  output->period_ns);
-	if (ret_overrun != 1)
-		pr_warn("%s: vblank timer overrun\n", __func__);
-
 	spin_lock(&output->lock);
 	ret = drm_crtc_handle_vblank(crtc);
 	if (!ret)
@@ -57,18 +49,14 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
 
 	dma_fence_end_signalling(fence_cookie);
 
-	return HRTIMER_RESTART;
+	return true;
 }
 
 static int vkms_enable_vblank(struct drm_crtc *crtc)
 {
-	struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 
-	hrtimer_setup(&out->vblank_hrtimer, &vkms_vblank_simulate, CLOCK_MONOTONIC,
-		      HRTIMER_MODE_REL);
-	out->period_ns = ktime_set(0, vblank->framedur_ns);
-	hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_REL);
+	drm_vblank_timer_start(&out->vtimer);
 
 	return 0;
 }
@@ -77,7 +65,7 @@ static void vkms_disable_vblank(struct drm_crtc *crtc)
 {
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 
-	hrtimer_cancel(&out->vblank_hrtimer);
+	drm_vblank_timer_cancel(&out->vtimer);
 }
 
 static bool vkms_get_vblank_timestamp(struct drm_crtc *crtc,
@@ -85,28 +73,9 @@ static bool vkms_get_vblank_timestamp(struct drm_crtc *crtc,
 				      bool in_vblank_irq)
 {
 	struct vkms_output *output = drm_crtc_to_vkms_output(crtc);
-	struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
-
-	if (!READ_ONCE(vblank->enabled)) {
-		*vblank_time = ktime_get();
-		return true;
-	}
-
-	*vblank_time = READ_ONCE(output->vblank_hrtimer.node.expires);
 
-	if (WARN_ON(*vblank_time == vblank->time))
-		return true;
-
-	/*
-	 * To prevent races we roll the hrtimer forward before we do any
-	 * interrupt processing - this is how real hw works (the interrupt is
-	 * only generated after all the vblank registers are updated) and what
-	 * the vblank core expects. Therefore we need to always correct the
-	 * timestampe by one frame.
-	 */
-	*vblank_time -= output->period_ns;
-
-	return true;
+	return drm_vblank_timer_get_vblank_timestamp(&output->vtimer, max_error,
+						     vblank_time, in_vblank_irq);
 }
 
 static struct drm_crtc_state *
@@ -274,6 +243,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, struct drm_plane *pri
 {
 	struct vkms_output *vkms_out;
 	struct drm_crtc *crtc;
+	struct drm_vblank_timer *vtimer;
 	int ret;
 
 	vkms_out = drmm_crtc_alloc_with_planes(dev, struct vkms_output, crtc,
@@ -285,6 +255,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, struct drm_plane *pri
 	}
 
 	crtc = &vkms_out->crtc;
+	vtimer = &vkms_out->vtimer;
 
 	drm_crtc_helper_add(crtc, &vkms_crtc_helper_funcs);
 
@@ -305,5 +276,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, struct drm_plane *pri
 	if (!vkms_out->composer_workq)
 		return ERR_PTR(-ENOMEM);
 
+	drmm_vblank_timer_init(vtimer, crtc, vkms_crtc_handle_vblank);
+
 	return vkms_out;
 }
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index a74a7fc3a056..126016898285 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -10,6 +10,7 @@
 #include <drm/drm_gem.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_encoder.h>
+#include <drm/drm_vblank_timer.h>
 #include <drm/drm_writeback.h>
 
 #define DEFAULT_DEVICE_NAME "vkms"
@@ -180,8 +181,9 @@ struct vkms_output {
 	struct drm_crtc crtc;
 	struct drm_writeback_connector wb_connector;
 	struct drm_encoder wb_encoder;
-	struct hrtimer vblank_hrtimer;
-	ktime_t period_ns;
+	struct drm_vblank_timer vtimer;
+	struct drm_pending_vblank_event *event;
+	/* ordered wq for composer_work */
 	struct workqueue_struct *composer_workq;
 	spinlock_t lock;
 
-- 
2.49.0