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Commit 6c234fe3 authored by Haneen Mohammed's avatar Haneen Mohammed Committed by Sean Paul
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drm/vkms: Implement CRC debugfs API 



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: default avatarHaneen Mohammed <hamohammed.sa@gmail.com>
[seanpaul fixed typo in vkms_crtc s/vblamk/vblank/]
Signed-off-by: default avatarSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/b948327f48c3e70ab232b4a0848ee6d033b26484.1533171495.git.hamohammed.sa@gmail.com
parent 3e77c4d0

drivers/gpu/drm/vkms/Makefile

+1 −1
Original line number Diff line number Diff line 
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

0 → 100644
+95 −0
Original line number Diff line number Diff line 
// 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);

	struct vkms_device *vdev = container_of(out, struct vkms_device,

						output);

	struct vkms_crc_data *primary_crc = NULL;

	struct drm_plane *plane;



	u32 crc32 = 0;



	drm_for_each_plane(plane, &vdev->drm) {

		struct vkms_plane_state *vplane_state;

		struct vkms_crc_data *crc_data;



		vplane_state = to_vkms_plane_state(plane->state);

		crc_data = vplane_state->crc_data;



		if (drm_framebuffer_read_refcount(&crc_data->fb) == 0)

			continue;



		if (plane->type == DRM_PLANE_TYPE_PRIMARY) {

			primary_crc = crc_data;

			break;

		}

	}



	if (primary_crc)

		crc32 = _vkms_get_crc(primary_crc);



	drm_crtc_add_crc_entry(crtc, true, crtc_state->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;



	/* make sure nothing is scheduled on crtc workq */

	flush_workqueue(out->crc_workq);



	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
Original line number Diff line number Diff line
@@ -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);
@@ -97,19 +112,23 @@ 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);



	if (vkms_state) {

		flush_work(&vkms_state->crc_work);

		kfree(vkms_state);

	}

}



static const struct drm_crtc_funcs vkms_crtc_funcs = {

	.set_config             = drm_atomic_helper_set_config,
@@ -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 vblank 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
Original line number Diff line number Diff line
@@ -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

+21 −0
Original line number Diff line number Diff line
@@ -20,20 +20,31 @@ 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 {
@@ -43,6 +54,11 @@ struct vkms_output { 
	struct hrtimer vblank_hrtimer;

	ktime_t period_ns;

	struct drm_pending_vblank_event *event;

	bool crc_enabled;

	/* ordered wq for crc_work */

	struct workqueue_struct *crc_workq;

	/* protects concurrent access to crc_data */

	spinlock_t lock;

};



struct vkms_device {
@@ -106,4 +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_ */