drivers/gpu/drm/vkms/vkms_composer.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+

 #include <linux/crc32.h>

 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_vblank.h>

 #include "vkms_drv.h"

 static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
 				 const struct vkms_composer *composer)
 {
 	u32 pixel;
 	int src_offset = composer->offset + (y * composer->pitch)
 				      + (x * composer->cpp);

 	pixel = *(u32 *)&buffer[src_offset];

 	return pixel;
 }

 /**
  * compute_crc - Compute CRC value on output frame
  *
  * @vaddr: address to final framebuffer
  * @composer: framebuffer's metadata
  *
  * returns CRC value computed using crc32 on the visible portion of
  * the final framebuffer at vaddr_out
  */
 static uint32_t compute_crc(const u8 *vaddr,
 			    const struct vkms_composer *composer)
 {
 	int x, y;
 	u32 crc = 0, pixel = 0;
 	int x_src = composer->src.x1 >> 16;
 	int y_src = composer->src.y1 >> 16;
 	int h_src = drm_rect_height(&composer->src) >> 16;
 	int w_src = drm_rect_width(&composer->src) >> 16;

 	for (y = y_src; y < y_src + h_src; ++y) {
 		for (x = x_src; x < x_src + w_src; ++x) {
 			pixel = get_pixel_from_buffer(x, y, vaddr, composer);
 			crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
 		}
 	}

 	return crc;
 }

 static u8 blend_channel(u8 src, u8 dst, u8 alpha)
 {
 	u32 pre_blend;
 	u8 new_color;

 	pre_blend = (src * 255 + dst * (255 - alpha));

 	/* Faster div by 255 */
 	new_color = ((pre_blend + ((pre_blend + 257) >> 8)) >> 8);

 	return new_color;
 }

 /**
  * alpha_blend - alpha blending equation
  * @argb_src: src pixel on premultiplied alpha mode
  * @argb_dst: dst pixel completely opaque
  *
  * blend pixels using premultiplied blend formula. The current DRM assumption
  * is that pixel color values have been already pre-multiplied with the alpha
  * channel values. See more drm_plane_create_blend_mode_property(). Also, this
  * formula assumes a completely opaque background.
  */
 static void alpha_blend(const u8 *argb_src, u8 *argb_dst)
 {
 	u8 alpha;

 	alpha = argb_src[3];
 	argb_dst[0] = blend_channel(argb_src[0], argb_dst[0], alpha);
 	argb_dst[1] = blend_channel(argb_src[1], argb_dst[1], alpha);
 	argb_dst[2] = blend_channel(argb_src[2], argb_dst[2], alpha);
 }

 /**
  * x_blend - blending equation that ignores the pixel alpha
  *
  * overwrites RGB color value from src pixel to dst pixel.
  */
 static void x_blend(const u8 *xrgb_src, u8 *xrgb_dst)
 {
 	memcpy(xrgb_dst, xrgb_src, sizeof(u8) * 3);
 }

 /**
  * blend - blend value at vaddr_src with value at vaddr_dst
  * @vaddr_dst: destination address
  * @vaddr_src: source address
  * @dst_composer: destination framebuffer's metadata
  * @src_composer: source framebuffer's metadata
  * @pixel_blend: blending equation based on plane format
  *
  * Blend the vaddr_src value with the vaddr_dst value using a pixel blend
  * equation according to the supported plane formats DRM_FORMAT_(A/XRGB8888)
  * and clearing alpha channel to an completely opaque background. This function
  * uses buffer's metadata to locate the new composite values at vaddr_dst.
  *
  * TODO: completely clear the primary plane (a = 0xff) before starting to blend
  * pixel color values
  */
 static void blend(void *vaddr_dst, void *vaddr_src,
 		  struct vkms_composer *dst_composer,
 		  struct vkms_composer *src_composer,
 		  void (*pixel_blend)(const u8 *, u8 *))
 {
 	int i, j, j_dst, i_dst;
 	int offset_src, offset_dst;
 	u8 *pixel_dst, *pixel_src;

 	int x_src = src_composer->src.x1 >> 16;
 	int y_src = src_composer->src.y1 >> 16;

 	int x_dst = src_composer->dst.x1;
 	int y_dst = src_composer->dst.y1;
 	int h_dst = drm_rect_height(&src_composer->dst);
 	int w_dst = drm_rect_width(&src_composer->dst);

 	int y_limit = y_src + h_dst;
 	int x_limit = x_src + w_dst;

 	for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
 		for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
 			offset_dst = dst_composer->offset
 				     + (i_dst * dst_composer->pitch)
 				     + (j_dst++ * dst_composer->cpp);
 			offset_src = src_composer->offset
 				     + (i * src_composer->pitch)
 				     + (j * src_composer->cpp);

 			pixel_src = (u8 *)(vaddr_src + offset_src);
 			pixel_dst = (u8 *)(vaddr_dst + offset_dst);
 			pixel_blend(pixel_src, pixel_dst);
 			/* clearing alpha channel (0xff)*/
 			pixel_dst[3] = 0xff;
 		}
 		i_dst++;
 	}
 }

 static void compose_plane(struct vkms_composer *primary_composer,
 			  struct vkms_composer *plane_composer,
 			  void *vaddr_out)
 {
 	struct drm_gem_object *plane_obj;
 	struct drm_gem_shmem_object *plane_shmem_obj;
 	struct drm_framebuffer *fb = &plane_composer->fb;
 	void (*pixel_blend)(const u8 *p_src, u8 *p_dst);

 	plane_obj = drm_gem_fb_get_obj(&plane_composer->fb, 0);
 	plane_shmem_obj = to_drm_gem_shmem_obj(plane_obj);

 	if (WARN_ON(!plane_shmem_obj->vaddr))
 		return;

 	if (fb->format->format == DRM_FORMAT_ARGB8888)
 		pixel_blend = &alpha_blend;
 	else
 		pixel_blend = &x_blend;

 	blend(vaddr_out, plane_shmem_obj->vaddr, primary_composer,
 	      plane_composer, pixel_blend);
 }

 static int compose_active_planes(void **vaddr_out,
 				 struct vkms_composer *primary_composer,
 				 struct vkms_crtc_state *crtc_state)
 {
 	struct drm_framebuffer *fb = &primary_composer->fb;
 	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
 	struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
 	int i;

 	if (!*vaddr_out) {
 		*vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
 		if (!*vaddr_out) {
 			DRM_ERROR("Cannot allocate memory for output frame.");
 			return -ENOMEM;
 		}
 	}

 	if (WARN_ON(!shmem_obj->vaddr))
 		return -EINVAL;

 	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);

 	/* If there are other planes besides primary, we consider the active
 	 * planes should be in z-order and compose them associatively:
 	 * ((primary <- overlay) <- cursor)
 	 */
 	for (i = 1; i < crtc_state->num_active_planes; i++)
 		compose_plane(primary_composer,
 			      crtc_state->active_planes[i]->composer,
 			      *vaddr_out);

 	return 0;
 }

 /**
  * vkms_composer_worker - ordered work_struct to compute CRC
  *
  * @work: work_struct
  *
  * Work handler for composing and computing CRCs. work_struct scheduled in
  * an ordered workqueue that's periodically scheduled to run by
  * _vblank_handle() and flushed at vkms_atomic_crtc_destroy_state().
  */
 void vkms_composer_worker(struct work_struct *work)
 {
 	struct vkms_crtc_state *crtc_state = container_of(work,
 						struct vkms_crtc_state,
 						composer_work);
 	struct drm_crtc *crtc = crtc_state->base.crtc;
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 	struct vkms_composer *primary_composer = NULL;
 	struct vkms_plane_state *act_plane = NULL;
 	bool crc_pending, wb_pending;
 	void *vaddr_out = NULL;
 	u32 crc32 = 0;
 	u64 frame_start, frame_end;
 	int ret;

 	spin_lock_irq(&out->composer_lock);
 	frame_start = crtc_state->frame_start;
 	frame_end = crtc_state->frame_end;
 	crc_pending = crtc_state->crc_pending;
 	wb_pending = crtc_state->wb_pending;
 	crtc_state->frame_start = 0;
 	crtc_state->frame_end = 0;
 	crtc_state->crc_pending = false;
 	spin_unlock_irq(&out->composer_lock);

 	/*
 	 * We raced with the vblank hrtimer and previous work already computed
 	 * the crc, nothing to do.
 	 */
 	if (!crc_pending)
 		return;

 	if (crtc_state->num_active_planes >= 1) {
 		act_plane = crtc_state->active_planes[0];
 		if (act_plane->base.plane->type == DRM_PLANE_TYPE_PRIMARY)
 			primary_composer = act_plane->composer;
 	}

 	if (!primary_composer)
 		return;

 	if (wb_pending)
 		vaddr_out = crtc_state->active_writeback;

 	ret = compose_active_planes(&vaddr_out, primary_composer,
 				    crtc_state);
 	if (ret) {
 		if (ret == -EINVAL && !wb_pending)
 			kfree(vaddr_out);
 		return;
 	}

 	crc32 = compute_crc(vaddr_out, primary_composer);

 	if (wb_pending) {
 		drm_writeback_signal_completion(&out->wb_connector, 0);
 		spin_lock_irq(&out->composer_lock);
 		crtc_state->wb_pending = false;
 		spin_unlock_irq(&out->composer_lock);
 	} else {
 		kfree(vaddr_out);
 	}

 	/*
 	 * The worker can fall behind the vblank hrtimer, make sure we catch up.
 	 */
 	while (frame_start <= frame_end)
 		drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
 }

 static const char * const pipe_crc_sources[] = {"auto"};

 const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
 					size_t *count)
 {
 	*count = ARRAY_SIZE(pipe_crc_sources);
 	return pipe_crc_sources;
 }

 static int vkms_crc_parse_source(const char *src_name, bool *enabled)
 {
 	int ret = 0;

 	if (!src_name) {
 		*enabled = false;
 	} else if (strcmp(src_name, "auto") == 0) {
 		*enabled = true;
 	} else {
 		*enabled = false;
 		ret = -EINVAL;
 	}

 	return ret;
 }

 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
 			   size_t *values_cnt)
 {
 	bool enabled;

 	if (vkms_crc_parse_source(src_name, &enabled) < 0) {
 		DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
 		return -EINVAL;
 	}

 	*values_cnt = 1;

 	return 0;
 }

 void vkms_set_composer(struct vkms_output *out, bool enabled)
 {
 	bool old_enabled;

 	if (enabled)
 		drm_crtc_vblank_get(&out->crtc);

 	spin_lock_irq(&out->lock);
 	old_enabled = out->composer_enabled;
 	out->composer_enabled = enabled;
 	spin_unlock_irq(&out->lock);

 	if (old_enabled)
 		drm_crtc_vblank_put(&out->crtc);
 }

 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
 {
 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 	bool enabled = false;
 	int ret = 0;

 	ret = vkms_crc_parse_source(src_name, &enabled);

 	vkms_set_composer(out, enabled);

 	return ret;
 }
	// SPDX-License-Identifier: GPL-2.0+

	#include <linux/crc32.h>

	#include <drm/drm_atomic.h>
	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_fourcc.h>
	#include <drm/drm_gem_framebuffer_helper.h>
	#include <drm/drm_gem_shmem_helper.h>
	#include <drm/drm_vblank.h>

	#include "vkms_drv.h"

	static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
	const struct vkms_composer *composer)
	{
	u32 pixel;
	int src_offset = composer->offset + (y * composer->pitch)
	+ (x * composer->cpp);

	pixel = (u32 )&buffer[src_offset];

	return pixel;
	}

	/**
	* compute_crc - Compute CRC value on output frame
	*
	* @vaddr: address to final framebuffer
	* @composer: framebuffer's metadata
	*
	* returns CRC value computed using crc32 on the visible portion of
	* the final framebuffer at vaddr_out
	*/
	static uint32_t compute_crc(const u8 *vaddr,
	const struct vkms_composer *composer)
	{
	int x, y;
	u32 crc = 0, pixel = 0;
	int x_src = composer->src.x1 >> 16;
	int y_src = composer->src.y1 >> 16;
	int h_src = drm_rect_height(&composer->src) >> 16;
	int w_src = drm_rect_width(&composer->src) >> 16;

	for (y = y_src; y < y_src + h_src; ++y) {
	for (x = x_src; x < x_src + w_src; ++x) {
	pixel = get_pixel_from_buffer(x, y, vaddr, composer);
	crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
	}
	}

	return crc;
	}

	static u8 blend_channel(u8 src, u8 dst, u8 alpha)
	{
	u32 pre_blend;
	u8 new_color;

	pre_blend = (src * 255 + dst * (255 - alpha));

	/* Faster div by 255 */
	new_color = ((pre_blend + ((pre_blend + 257) >> 8)) >> 8);

	return new_color;
	}

	/**
	* alpha_blend - alpha blending equation
	* @argb_src: src pixel on premultiplied alpha mode
	* @argb_dst: dst pixel completely opaque
	*
	* blend pixels using premultiplied blend formula. The current DRM assumption
	* is that pixel color values have been already pre-multiplied with the alpha
	* channel values. See more drm_plane_create_blend_mode_property(). Also, this
	* formula assumes a completely opaque background.
	*/
	static void alpha_blend(const u8 argb_src, u8 argb_dst)
	{
	u8 alpha;

	alpha = argb_src[3];
	argb_dst[0] = blend_channel(argb_src[0], argb_dst[0], alpha);
	argb_dst[1] = blend_channel(argb_src[1], argb_dst[1], alpha);
	argb_dst[2] = blend_channel(argb_src[2], argb_dst[2], alpha);
	}

	/**
	* x_blend - blending equation that ignores the pixel alpha
	*
	* overwrites RGB color value from src pixel to dst pixel.
	*/
	static void x_blend(const u8 xrgb_src, u8 xrgb_dst)
	{
	memcpy(xrgb_dst, xrgb_src, sizeof(u8) * 3);
	}

	/**
	* blend - blend value at vaddr_src with value at vaddr_dst
	* @vaddr_dst: destination address
	* @vaddr_src: source address
	* @dst_composer: destination framebuffer's metadata
	* @src_composer: source framebuffer's metadata
	* @pixel_blend: blending equation based on plane format
	*
	* Blend the vaddr_src value with the vaddr_dst value using a pixel blend
	* equation according to the supported plane formats DRM_FORMAT_(A/XRGB8888)
	* and clearing alpha channel to an completely opaque background. This function
	* uses buffer's metadata to locate the new composite values at vaddr_dst.
	*
	* TODO: completely clear the primary plane (a = 0xff) before starting to blend
	* pixel color values
	*/
	static void blend(void vaddr_dst, void vaddr_src,
	struct vkms_composer *dst_composer,
	struct vkms_composer *src_composer,
	void (pixel_blend)(const u8 , u8 *))
	{
	int i, j, j_dst, i_dst;
	int offset_src, offset_dst;
	u8 pixel_dst, pixel_src;

	int x_src = src_composer->src.x1 >> 16;
	int y_src = src_composer->src.y1 >> 16;

	int x_dst = src_composer->dst.x1;
	int y_dst = src_composer->dst.y1;
	int h_dst = drm_rect_height(&src_composer->dst);
	int w_dst = drm_rect_width(&src_composer->dst);

	int y_limit = y_src + h_dst;
	int x_limit = x_src + w_dst;

	for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
	for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
	offset_dst = dst_composer->offset
	+ (i_dst * dst_composer->pitch)
	+ (j_dst++ * dst_composer->cpp);
	offset_src = src_composer->offset
	+ (i * src_composer->pitch)
	+ (j * src_composer->cpp);

	pixel_src = (u8 *)(vaddr_src + offset_src);
	pixel_dst = (u8 *)(vaddr_dst + offset_dst);
	pixel_blend(pixel_src, pixel_dst);
	/* clearing alpha channel (0xff)*/
	pixel_dst[3] = 0xff;
	}
	i_dst++;
	}
	}

	static void compose_plane(struct vkms_composer *primary_composer,
	struct vkms_composer *plane_composer,
	void *vaddr_out)
	{
	struct drm_gem_object *plane_obj;
	struct drm_gem_shmem_object *plane_shmem_obj;
	struct drm_framebuffer *fb = &plane_composer->fb;
	void (pixel_blend)(const u8 p_src, u8 *p_dst);

	plane_obj = drm_gem_fb_get_obj(&plane_composer->fb, 0);
	plane_shmem_obj = to_drm_gem_shmem_obj(plane_obj);

	if (WARN_ON(!plane_shmem_obj->vaddr))
	return;

	if (fb->format->format == DRM_FORMAT_ARGB8888)
	pixel_blend = &alpha_blend;
	else
	pixel_blend = &x_blend;

	blend(vaddr_out, plane_shmem_obj->vaddr, primary_composer,
	plane_composer, pixel_blend);
	}

	static int compose_active_planes(void **vaddr_out,
	struct vkms_composer *primary_composer,
	struct vkms_crtc_state *crtc_state)
	{
	struct drm_framebuffer *fb = &primary_composer->fb;
	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
	struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
	int i;

	if (!*vaddr_out) {
	*vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
	if (!*vaddr_out) {
	DRM_ERROR("Cannot allocate memory for output frame.");
	return -ENOMEM;
	}
	}

	if (WARN_ON(!shmem_obj->vaddr))
	return -EINVAL;

	memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);

	/* If there are other planes besides primary, we consider the active
	* planes should be in z-order and compose them associatively:
	* ((primary <- overlay) <- cursor)
	*/
	for (i = 1; i < crtc_state->num_active_planes; i++)
	compose_plane(primary_composer,
	crtc_state->active_planes[i]->composer,
	*vaddr_out);

	return 0;
	}

	/**
	* vkms_composer_worker - ordered work_struct to compute CRC
	*
	* @work: work_struct
	*
	* Work handler for composing and computing CRCs. work_struct scheduled in
	* an ordered workqueue that's periodically scheduled to run by
	* _vblank_handle() and flushed at vkms_atomic_crtc_destroy_state().
	*/
	void vkms_composer_worker(struct work_struct *work)
	{
	struct vkms_crtc_state *crtc_state = container_of(work,
	struct vkms_crtc_state,
	composer_work);
	struct drm_crtc *crtc = crtc_state->base.crtc;
	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
	struct vkms_composer *primary_composer = NULL;
	struct vkms_plane_state *act_plane = NULL;
	bool crc_pending, wb_pending;
	void *vaddr_out = NULL;
	u32 crc32 = 0;
	u64 frame_start, frame_end;
	int ret;

	spin_lock_irq(&out->composer_lock);
	frame_start = crtc_state->frame_start;
	frame_end = crtc_state->frame_end;
	crc_pending = crtc_state->crc_pending;
	wb_pending = crtc_state->wb_pending;
	crtc_state->frame_start = 0;
	crtc_state->frame_end = 0;
	crtc_state->crc_pending = false;
	spin_unlock_irq(&out->composer_lock);

	/*
	* We raced with the vblank hrtimer and previous work already computed
	* the crc, nothing to do.
	*/
	if (!crc_pending)
	return;

	if (crtc_state->num_active_planes >= 1) {
	act_plane = crtc_state->active_planes[0];
	if (act_plane->base.plane->type == DRM_PLANE_TYPE_PRIMARY)
	primary_composer = act_plane->composer;
	}

	if (!primary_composer)
	return;

	if (wb_pending)
	vaddr_out = crtc_state->active_writeback;

	ret = compose_active_planes(&vaddr_out, primary_composer,
	crtc_state);
	if (ret) {
	if (ret == -EINVAL && !wb_pending)
	kfree(vaddr_out);
	return;
	}

	crc32 = compute_crc(vaddr_out, primary_composer);

	if (wb_pending) {
	drm_writeback_signal_completion(&out->wb_connector, 0);
	spin_lock_irq(&out->composer_lock);
	crtc_state->wb_pending = false;
	spin_unlock_irq(&out->composer_lock);
	} else {
	kfree(vaddr_out);
	}

	/*
	* The worker can fall behind the vblank hrtimer, make sure we catch up.
	*/
	while (frame_start <= frame_end)
	drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
	}

	static const char * const pipe_crc_sources[] = {"auto"};

	const char const vkms_get_crc_sources(struct drm_crtc *crtc,
	size_t *count)
	{
	*count = ARRAY_SIZE(pipe_crc_sources);
	return pipe_crc_sources;
	}

	static int vkms_crc_parse_source(const char src_name, bool enabled)
	{
	int ret = 0;

	if (!src_name) {
	*enabled = false;
	} else if (strcmp(src_name, "auto") == 0) {
	*enabled = true;
	} else {
	*enabled = false;
	ret = -EINVAL;
	}

	return ret;
	}

	int vkms_verify_crc_source(struct drm_crtc crtc, const char src_name,
	size_t *values_cnt)
	{
	bool enabled;

	if (vkms_crc_parse_source(src_name, &enabled) < 0) {
	DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
	return -EINVAL;
	}

	*values_cnt = 1;

	return 0;
	}

	void vkms_set_composer(struct vkms_output *out, bool enabled)
	{
	bool old_enabled;

	if (enabled)
	drm_crtc_vblank_get(&out->crtc);

	spin_lock_irq(&out->lock);
	old_enabled = out->composer_enabled;
	out->composer_enabled = enabled;
	spin_unlock_irq(&out->lock);

	if (old_enabled)
	drm_crtc_vblank_put(&out->crtc);
	}

	int vkms_set_crc_source(struct drm_crtc crtc, const char src_name)
	{
	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
	bool enabled = false;
	int ret = 0;

	ret = vkms_crc_parse_source(src_name, &enabled);

	vkms_set_composer(out, enabled);

	return ret;
	}