drm/vkms: Add CRC support

Subclass plane state struct to enable storing driver's private state. This patch only adds the base drm_plane_state struct and the atomic functions that handle it.

Signed-off-by Haneen Mohammed <[email protected]>

---
 drivers/gpu/drm/vkms/vkms_drv.h   | 10 +++++++
 drivers/gpu/drm/vkms/vkms_plane.c | 47 +++++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 3 deletions(-)

drivers/gpu/drm/vkms/vkms_drv.h +10 -0

index 75e52d61e65d..aa2632ff5f06 100644
@@ -20,6 +20,13 @@ static const u32 vkms_formats[] = {
 	DRM_FORMAT_XRGB8888,
 };
 
+/* vkms_plane_state - Driver specific plane state
+ * @base: base plane state
+ */
+struct vkms_plane_state {
+	struct drm_plane_state base;
+};
+
 /**
  * vkms_crtc_state - Driver specific CRTC state
  * @base: base CRTC state

@@ -63,6 +70,9 @@ struct vkms_gem_object {
 #define to_vkms_crtc_state(target)\
 	container_of(target, struct vkms_crtc_state, base)
 
+#define to_vkms_plane_state(target)\
+	container_of(target, struct vkms_plane_state, base)
+
 /* CRTC */
 int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
 		   struct drm_plane *primary, struct drm_plane *cursor);

drivers/gpu/drm/vkms/vkms_plane.c +44 -3

index 8191940844e5..70fca22bc51b 100644
@@ -12,13 +12,54 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 
+static struct drm_plane_state *
+vkms_plane_duplicate_state(struct drm_plane *plane)
+{
+	struct vkms_plane_state *vkms_state;
+
+	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
+	if (!vkms_state)
+		return NULL;
+
+	__drm_atomic_helper_plane_duplicate_state(plane,
+						  &vkms_state->base);
+
+	return &vkms_state->base;
+}
+
+static void vkms_plane_destroy_state(struct drm_plane *plane,
+				     struct drm_plane_state *old_state)
+{
+	struct vkms_plane_state *vkms_state = to_vkms_plane_state(old_state);
+
+	__drm_atomic_helper_plane_destroy_state(old_state);
+	kfree(vkms_state);
+}
+
+static void vkms_plane_reset(struct drm_plane *plane)
+{
+	struct vkms_plane_state *vkms_state;
+
+	if (plane->state)
+		vkms_plane_destroy_state(plane, plane->state);
+
+	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
+	if (!vkms_state) {
+		DRM_ERROR("Cannot allocate vkms_plane_state\n");
+		return;
+	}
+
+	plane->state = &vkms_state->base;
+	plane->state->plane = plane;
+}
+
 static const struct drm_plane_funcs vkms_plane_funcs = {
 	.update_plane		= drm_atomic_helper_update_plane,
 	.disable_plane		= drm_atomic_helper_disable_plane,
 	.destroy		= drm_plane_cleanup,
-	.reset			= drm_atomic_helper_plane_reset,
-	.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
-	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
+	.reset			= vkms_plane_reset,
+	.atomic_duplicate_state = vkms_plane_duplicate_state,
+	.atomic_destroy_state	= vkms_plane_destroy_state,
 };
 
 static void vkms_primary_plane_update(struct drm_plane *plane,

Signature · 1 line

2.17.1

This patch implement the necessary functions to compute and add CRCs entries:

- Implement the set_crc_source() callback.
- Compute CRC using crc32 on the visible part of the framebuffer.
- Use ordered workqueue per output to compute and add CRC at the end of a vblank.
- Use appropriate synchronization methods since the CRC computation must be atomic wrt the generated vblank event for a given atomic update, by using spinlock across atomic_begin/atomic_flush to wrap the event handling code completely and match the flip event with the CRC.

Since vkms_crc_work_handle() can sleep, spinlock can't be acquired while accessing vkms_output->primary_crc to compute CRC. To make sure the data is updated and released without conflict with the vkms_crc_work_handle(), the work_struct is flushed @crtc_destroy and the data is updated before scheduling the work handle again, as follow:

* CRC data update:
1- store vkms_crc_data {fb, src} per plane_state 2- @plane_duplicate_state -> allocate vkms_crc_data 3- during atomic commit (@atomic_update) ->

	a) copy {fb, src} to plane_state->crc_data
	b) get reference to fb,

3- @plane_destroy_state -> a) if (fb refcount) remove reference to fb
b) deallocate crc_data

* Atomic Commit:
1- vkms_plane_atomic_check
2- vkms_prepare_fb -> vmap vkms_gem_obj->vaddr
3- atomic_begin -> hold crc spinlock
4- atomic_plane_update -> a) update vkms_output->primary_crc
b) get reference to fb
5- atomic_flush -> a) send vblank event while holding event_lock
b) release crc spinlock

* hrtimer regular callback:
1- hold crc spinlock
2- drm_crtc_handle_vblank()
3- queue vkms_crc_work_handle
4- release crc spinlock

* cleanup:
1- @cleanup_fb ->vunmap vkms_gem_obj->vaddr
2- @crtc_destroy -> flush work struct
3- @plane_destroy -> a) if (fb refcount) remove reference to fb
b) deallocate crc_data

Signed-off-by Haneen Mohammed <[email protected]>

---
 drivers/gpu/drm/vkms/Makefile     |  2 +-
 drivers/gpu/drm/vkms/vkms_crc.c   | 75 +++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_crtc.c  | 56 +++++++++++++++++++----
 drivers/gpu/drm/vkms/vkms_drv.c   |  1 +
 drivers/gpu/drm/vkms/vkms_drv.h   | 22 +++++++++
 drivers/gpu/drm/vkms/vkms_plane.c | 44 ++++++++++++++++++
 6 files changed, 191 insertions(+), 9 deletions(-)
 create mode 100644 drivers/gpu/drm/vkms/vkms_crc.c

drivers/gpu/drm/vkms/Makefile +1 -1

index 986297da51bf..37966914f70b 100644
@@ -1,3 +1,3 @@
-vkms-y := vkms_drv.o vkms_plane.o vkms_output.o vkms_crtc.o vkms_gem.o
+vkms-y := vkms_drv.o vkms_plane.o vkms_output.o vkms_crtc.o vkms_gem.o vkms_crc.o
 
 obj-$(CONFIG_DRM_VKMS) += vkms.o

drivers/gpu/drm/vkms/vkms_crc.c new file +75 -0

new file mode 100644
index 000000000000..d4f94ac932a7
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "vkms_drv.h"
+#include <linux/crc32.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+
+static uint32_t _vkms_get_crc(struct vkms_crc_data *crc_data)
+{
+	struct drm_framebuffer *fb = &crc_data->fb;
+	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
+	struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj);
+	u32 crc = 0;
+	int i = 0;
+	unsigned int x = crc_data->src.x1 >> 16;
+	unsigned int y = crc_data->src.y1 >> 16;
+	unsigned int height = drm_rect_height(&crc_data->src) >> 16;
+	unsigned int width = drm_rect_width(&crc_data->src) >> 16;
+	unsigned int cpp = fb->format->cpp[0];
+	unsigned int src_offset;
+	unsigned int size_byte = width * cpp;
+	void *vaddr;
+
+	mutex_lock(&vkms_obj->pages_lock);
+	vaddr = vkms_obj->vaddr;
+	if (WARN_ON(!vaddr))
+		return crc;
+
+	for (i = y; i < y + height; i++) {
+		src_offset = fb->offsets[0] + (i * fb->pitches[0]) + (x * cpp);
+		crc = crc32_le(crc, vaddr + src_offset, size_byte);
+	}
+	mutex_unlock(&vkms_obj->pages_lock);
+
+	return crc;
+}
+
+void vkms_crc_work_handle(struct work_struct *work)
+{
+	struct vkms_crtc_state *crtc_state = container_of(work,
+						struct vkms_crtc_state,
+						crc_work);
+	struct drm_crtc *crtc = crtc_state->base.crtc;
+	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
+
+	if (crtc_state && out->crc_enabled) {
+		unsigned int n_frame = crtc_state->n_frame;
+		u32 crc32 = 0;
+
+		if (out->primary_crc)
+			crc32 = _vkms_get_crc(out->primary_crc);
+
+		drm_crtc_add_crc_entry(crtc, true, n_frame, &crc32);
+	}
+}
+
+int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name,
+			size_t *values_cnt)
+{
+	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
+	bool enabled = false;
+	unsigned long flags;
+	int ret = 0;
+
+	if (src_name && strcmp(src_name, "auto") == 0)
+		enabled = true;
+	else if (src_name)
+		ret = -EINVAL;
+
+	*values_cnt = 1;
+
+	spin_lock_irqsave(&out->lock, flags);
+	out->crc_enabled = enabled;
+	spin_unlock_irqrestore(&out->lock, flags);
+
+	return ret;
+}

drivers/gpu/drm/vkms/vkms_crtc.c +48 -8

index 26babb85ca77..a6c080d7f7ae 100644
@@ -10,18 +10,33 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
 
-static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
+static void _vblank_handle(struct vkms_output *output)
 {
-	struct vkms_output *output = container_of(timer, struct vkms_output,
-						  vblank_hrtimer);
 	struct drm_crtc *crtc = &output->crtc;
-	int ret_overrun;
+	struct vkms_crtc_state *state = to_vkms_crtc_state(crtc->state);
 	bool ret;
 
+	spin_lock(&output->lock);
 	ret = drm_crtc_handle_vblank(crtc);
 	if (!ret)
 		DRM_ERROR("vkms failure on handling vblank");
 
+	if (state && output->crc_enabled) {
+		state->n_frame = drm_crtc_accurate_vblank_count(crtc);
+		queue_work(output->crc_workq, &state->crc_work);
+	}
+
+	spin_unlock(&output->lock);
+}
+
+static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
+{
+	struct vkms_output *output = container_of(timer, struct vkms_output,
+						  vblank_hrtimer);
+	int ret_overrun;
+
+	_vblank_handle(output);
+
 	ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
 					  output->period_ns);
 

@@ -97,18 +112,22 @@ vkms_atomic_crtc_duplicate_state(struct drm_crtc *crtc)
 
 	__drm_atomic_helper_crtc_duplicate_state(crtc, &vkms_state->base);
 
+	INIT_WORK(&vkms_state->crc_work, vkms_crc_work_handle);
+
 	return &vkms_state->base;
 }
 
 static void vkms_atomic_crtc_destroy_state(struct drm_crtc *crtc,
 					   struct drm_crtc_state *state)
 {
-	struct vkms_crtc_state *vkms_state;
-
-	vkms_state = to_vkms_crtc_state(state);
+	struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(state);
 
 	__drm_atomic_helper_crtc_destroy_state(state);
-	kfree(vkms_state);
+
+	if (vkms_state) {
+		flush_work(&vkms_state->crc_work);
+		kfree(vkms_state);
+	}
 }
 
 static const struct drm_crtc_funcs vkms_crtc_funcs = {

@@ -120,6 +139,7 @@ static const struct drm_crtc_funcs vkms_crtc_funcs = {
 	.atomic_destroy_state   = vkms_atomic_crtc_destroy_state,
 	.enable_vblank		= vkms_enable_vblank,
 	.disable_vblank		= vkms_disable_vblank,
+	.set_crc_source		= vkms_set_crc_source,
 };
 
 static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,

@@ -134,9 +154,21 @@ static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
 	drm_crtc_vblank_off(crtc);
 }
 
+static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
+				   struct drm_crtc_state *old_crtc_state)
+{
+	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
+
+	/* This lock is held across the atomic commit to block vblamk timer
+	 * from scheduling vkms_crc_work_handle until the crc_data is updated
+	 */
+	spin_lock_irq(&vkms_output->lock);
+}
+
 static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
 				   struct drm_crtc_state *old_crtc_state)
 {
+	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
 	unsigned long flags;
 
 	if (crtc->state->event) {

@@ -151,9 +183,12 @@ static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
 
 		crtc->state->event = NULL;
 	}
+
+	spin_unlock_irq(&vkms_output->lock);
 }
 
 static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
+	.atomic_begin	= vkms_crtc_atomic_begin,
 	.atomic_flush	= vkms_crtc_atomic_flush,
 	.atomic_enable	= vkms_crtc_atomic_enable,
 	.atomic_disable	= vkms_crtc_atomic_disable,

@@ -162,6 +197,7 @@ static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
 int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
 		   struct drm_plane *primary, struct drm_plane *cursor)
 {
+	struct vkms_output *vkms_out = drm_crtc_to_vkms_output(crtc);
 	int ret;
 
 	ret = drm_crtc_init_with_planes(dev, crtc, primary, cursor,

@@ -173,5 +209,9 @@ int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
 
 	drm_crtc_helper_add(crtc, &vkms_crtc_helper_funcs);
 
+	spin_lock_init(&vkms_out->lock);
+
+	vkms_out->crc_workq = alloc_ordered_workqueue("vkms_crc_workq", 0);
+
 	return ret;
 }

drivers/gpu/drm/vkms/vkms_drv.c +1 -0

index 37aa2ef33b21..5d78bd97e69c 100644
@@ -46,6 +46,7 @@ static void vkms_release(struct drm_device *dev)
 	platform_device_unregister(vkms->platform);
 	drm_mode_config_cleanup(&vkms->drm);
 	drm_dev_fini(&vkms->drm);
+	destroy_workqueue(vkms->output.crc_workq);
 }
 
 static struct drm_driver vkms_driver = {

drivers/gpu/drm/vkms/vkms_drv.h +11 -0

index aa2632ff5f06..9eb2d8eb1720 100644
@@ -20,19 +20,30 @@ static const u32 vkms_formats[] = {
 	DRM_FORMAT_XRGB8888,
 };
 
+struct vkms_crc_data {
+	struct drm_rect src;
+	struct drm_framebuffer fb;
+};
+
 /* vkms_plane_state - Driver specific plane state
  * @base: base plane state
+ * @crc_data: data required for CRC computation
  */
 struct vkms_plane_state {
 	struct drm_plane_state base;
+	struct vkms_crc_data *crc_data;
 };
 
 /**
  * vkms_crtc_state - Driver specific CRTC state
  * @base: base CRTC state
+ * @crc_work: work struct to compute and add CRC entries
+ * @n_frame: frame number for computed CRC
  */
 struct vkms_crtc_state {
 	struct drm_crtc_state base;
+	struct work_struct crc_work;
+	unsigned int n_frame;
 };
 
 struct vkms_output {

drivers/gpu/drm/vkms/vkms_drv.h +7 -0

+	/* protects concurrent access to crc_data */
+	spinlock_t lock;
 };
 
 struct vkms_device {

@@ -105,4 +122,9 @@ int vkms_gem_vmap(struct drm_gem_object *obj);
 
 void vkms_gem_vunmap(struct drm_gem_object *obj);
 
+/* CRC Support */
+int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name,
+			size_t *values_cnt);
+void vkms_crc_work_handle(struct work_struct *work);
+
 #endif /* _VKMS_DRV_H_ */

drivers/gpu/drm/vkms/vkms_plane.c +44 -0

index 70fca22bc51b..c2e783c6e626 100644
@@ -16,11 +16,18 @@ static struct drm_plane_state *
 vkms_plane_duplicate_state(struct drm_plane *plane)
 {
 	struct vkms_plane_state *vkms_state;
+	struct vkms_crc_data *crc_data;
 
 	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
 	if (!vkms_state)
 		return NULL;
 
+	crc_data = kzalloc(sizeof(*crc_data), GFP_KERNEL);
+	if (WARN_ON(!crc_data))
+		DRM_INFO("Couldn't allocate crc_data");
+
+	vkms_state->crc_data = crc_data;
+
 	__drm_atomic_helper_plane_duplicate_state(plane,
 						  &vkms_state->base);
 

@@ -31,6 +38,27 @@ static void vkms_plane_destroy_state(struct drm_plane *plane,
 				     struct drm_plane_state *old_state)
 {
 	struct vkms_plane_state *vkms_state = to_vkms_plane_state(old_state);
+	struct drm_crtc *crtc = vkms_state->base.crtc;
+
+	if (crtc) {
+		struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
+		unsigned long flags;
+
+		if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
+			spin_lock_irqsave(&out->lock, flags);
+			out->primary_crc = NULL;
+			spin_unlock_irqrestore(&out->lock, flags);
+		}
+
+		/* dropping the reference we acquired in
+		 * vkms_primary_plane_update()
+		 */
+		if (drm_framebuffer_read_refcount(&vkms_state->crc_data->fb))
+			drm_framebuffer_put(&vkms_state->crc_data->fb);
+	}
+
+	kfree(vkms_state->crc_data);
+	vkms_state->crc_data = NULL;
 
 	__drm_atomic_helper_plane_destroy_state(old_state);
 	kfree(vkms_state);

@@ -65,6 +93,22 @@ static const struct drm_plane_funcs vkms_plane_funcs = {
 static void vkms_primary_plane_update(struct drm_plane *plane,
 				      struct drm_plane_state *old_state)
 {
+	struct vkms_plane_state *vkms_plane_state;
+	struct vkms_crc_data *crc_data;
+	struct vkms_output *out;
+
+	if (!plane->state->crtc || !plane->state->fb)
+		return;
+
+	vkms_plane_state = to_vkms_plane_state(plane->state);
+	crc_data = vkms_plane_state->crc_data;
+	memcpy(&crc_data->src, &plane->state->src, sizeof(struct drm_rect));
+	memcpy(&crc_data->fb, plane->state->fb, sizeof(struct drm_framebuffer));
+	drm_framebuffer_get(&crc_data->fb);
+
+	out = drm_crtc_to_vkms_output(plane->state->crtc);
+	if (plane->type == DRM_PLANE_TYPE_PRIMARY)
+		out->primary_crc = crc_data;
 }
 
 static int vkms_plane_atomic_check(struct drm_plane *plane,

Signature · 1 line

2.17.1