[PATCH] drm/vkms: Add vblank events simulated by hrtimers

[Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>]

This commit adds regular vblank events simulated through hrtimers, which
is a feature required by VKMS to mimic real hardware. In this sense,
this commit adopts a default frequency of 60Hz for vblank interval.
Finally, this commit implements handlers for some of the atomic and
vblank hooks.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
---
Note:
	- This patch depends on the patchset "drm/vkms: Updates to meet basic
		kms_flip requirements"
		link: https://lists.freedesktop.org/archives/dri-devel/2018-June/180823.html

 drivers/gpu/drm/vkms/vkms_crtc.c | 90 +++++++++++++++++++++++++++++++-
 drivers/gpu/drm/vkms/vkms_drv.c  |  6 +++
 drivers/gpu/drm/vkms/vkms_drv.h  |  9 ++++
 3 files changed, 103 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 84cc05506b09..73aae129c37d 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -10,6 +10,52 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
 
+static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
+{
+	struct vkms_output *output = container_of(timer, struct vkms_output,
+						  vblank_hrtimer);
+	struct drm_crtc *crtc = &output->crtc;
+	unsigned long flags;
+	int ret_overrun;
+	bool ret;
+
+	ret = drm_crtc_handle_vblank(&output->crtc);
+	if (!ret)
+		DRM_ERROR("vkms failure on handling vblank");
+
+	spin_lock_irqsave(&crtc->dev->event_lock, flags);
+	if (output->event) {
+		drm_crtc_send_vblank_event(crtc, output->event);
+		drm_crtc_vblank_put(crtc);
+		output->event = NULL;
+	}
+	spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
+
+	ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
+					  output->period_ns);
+
+	return HRTIMER_RESTART;
+}
+
+static int vkms_enable_vblank(struct drm_crtc *crtc)
+{
+	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
+
+	hrtimer_init(&out->vblank_hrtimer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
+	out->vblank_hrtimer.function = &vkms_vblank_simulate;
+	out->period_ns = ktime_set(0, DEFAULT_VBLANK_NS);
+	hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_ABS);
+
+	return 0;
+}
+
+static void vkms_disable_vblank(struct drm_crtc *crtc)
+{
+	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
+
+	hrtimer_cancel(&out->vblank_hrtimer);
+}
+
 static const struct drm_crtc_funcs vkms_crtc_funcs = {
 	.set_config             = drm_atomic_helper_set_config,
 	.destroy                = drm_crtc_cleanup,
@@ -17,6 +63,8 @@ static const struct drm_crtc_funcs vkms_crtc_funcs = {
 	.reset                  = drm_atomic_helper_crtc_reset,
 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 	.atomic_destroy_state   = drm_atomic_helper_crtc_destroy_state,
+	.enable_vblank		= vkms_enable_vblank,
+	.disable_vblank		= vkms_disable_vblank,
 };
 
 static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
@@ -27,12 +75,50 @@ static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
 
 static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,
 				    struct drm_crtc_state *old_state)
+{
+	drm_crtc_vblank_on(crtc);
+}
+
+static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
+				   struct drm_crtc_state *old_s)
+{
+	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
+
+	if (crtc->state->event) {
+		crtc->state->event->pipe = drm_crtc_index(crtc);
+		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
+
+		vkms_output->event = crtc->state->event;
+		crtc->state->event = NULL;
+	}
+}
+
+static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
+				   struct drm_crtc_state *old_crtc_state)
+{
+	struct drm_pending_vblank_event *event = crtc->state->event;
+
+	if (!event)
+		return;
+
+	crtc->state->event = NULL;
+
+	spin_lock_irq(&crtc->dev->event_lock);
+	if (drm_crtc_vblank_get(crtc))
+		drm_crtc_send_vblank_event(crtc, event);
+	spin_unlock_irq(&crtc->dev->event_lock);
+}
+
+static void vkms_crtc_commit(struct drm_crtc *crtc)
 {
 }
 
 static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
-	.atomic_check  = vkms_crtc_atomic_check,
-	.atomic_enable = vkms_crtc_atomic_enable,
+	.atomic_check	= vkms_crtc_atomic_check,
+	.atomic_enable	= vkms_crtc_atomic_enable,
+	.atomic_flush	= vkms_crtc_atomic_flush,
+	.atomic_begin	= vkms_crtc_atomic_begin,
+	.commit		= vkms_crtc_commit,
 };
 
 int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index fe93f8c17997..c56d66d9ec56 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -102,6 +102,12 @@ static int __init vkms_init(void)
 		goto out_fini;
 	}
 
+	ret = drm_vblank_init(&vkms_device->drm, 1);
+	if (ret) {
+		DRM_ERROR("Failed to vblank\n");
+		goto out_fini;
+	}
+
 	ret = vkms_modeset_init(vkms_device);
 	if (ret)
 		goto out_unregister;
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 76f1720f81a5..f115e7d1ae03 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -5,6 +5,7 @@
 #include <drm/drm.h>
 #include <drm/drm_gem.h>
 #include <drm/drm_encoder.h>
+#include <linux/hrtimer.h>
 
 #define XRES_MIN    32
 #define YRES_MIN    32
@@ -15,6 +16,8 @@
 #define XRES_MAX  8192
 #define YRES_MAX  8192
 
+#define DEFAULT_VBLANK_NS 16666666
+
 static const u32 vkms_formats[] = {
 	DRM_FORMAT_XRGB8888,
 };
@@ -23,6 +26,9 @@ struct vkms_output {
 	struct drm_crtc crtc;
 	struct drm_encoder encoder;
 	struct drm_connector connector;
+	struct hrtimer vblank_hrtimer;
+	ktime_t period_ns;
+	struct drm_pending_vblank_event *event;
 };
 
 struct vkms_device {
@@ -37,6 +43,9 @@ struct vkms_gem_object {
 	struct page **pages;
 };
 
+#define drm_crtc_to_vkms_output(target) \
+	container_of(target, struct vkms_output, crtc)
+
 int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
 		   struct drm_plane *primary, struct drm_plane *cursor);
 
-- 
2.17.1

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