| // 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_vblank.h> |
| #include <linux/minmax.h> |
| |
| #include "vkms_drv.h" |
| |
| static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha) |
| { |
| u32 new_color; |
| |
| new_color = (src * 0xffff + dst * (0xffff - alpha)); |
| |
| return DIV_ROUND_CLOSEST(new_color, 0xffff); |
| } |
| |
| /** |
| * pre_mul_alpha_blend - alpha blending equation |
| * @src_frame_info: source framebuffer's metadata |
| * @stage_buffer: The line with the pixels from src_plane |
| * @output_buffer: A line buffer that receives all the blends output |
| * |
| * Using the information from the `frame_info`, this blends only the |
| * necessary pixels from the `stage_buffer` to the `output_buffer` |
| * 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 pre_mul_alpha_blend(struct vkms_frame_info *frame_info, |
| struct line_buffer *stage_buffer, |
| struct line_buffer *output_buffer) |
| { |
| int x_dst = frame_info->dst.x1; |
| struct pixel_argb_u16 *out = output_buffer->pixels + x_dst; |
| struct pixel_argb_u16 *in = stage_buffer->pixels; |
| int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), |
| stage_buffer->n_pixels); |
| |
| for (int x = 0; x < x_limit; x++) { |
| out[x].a = (u16)0xffff; |
| out[x].r = pre_mul_blend_channel(in[x].r, out[x].r, in[x].a); |
| out[x].g = pre_mul_blend_channel(in[x].g, out[x].g, in[x].a); |
| out[x].b = pre_mul_blend_channel(in[x].b, out[x].b, in[x].a); |
| } |
| } |
| |
| static bool check_y_limit(struct vkms_frame_info *frame_info, int y) |
| { |
| if (y >= frame_info->dst.y1 && y < frame_info->dst.y2) |
| return true; |
| |
| return false; |
| } |
| |
| static void fill_background(const struct pixel_argb_u16 *background_color, |
| struct line_buffer *output_buffer) |
| { |
| for (size_t i = 0; i < output_buffer->n_pixels; i++) |
| output_buffer->pixels[i] = *background_color; |
| } |
| |
| /** |
| * @wb_frame_info: The writeback frame buffer metadata |
| * @crtc_state: The crtc state |
| * @crc32: The crc output of the final frame |
| * @output_buffer: A buffer of a row that will receive the result of the blend(s) |
| * @stage_buffer: The line with the pixels from plane being blend to the output |
| * |
| * This function blends the pixels (Using the `pre_mul_alpha_blend`) |
| * from all planes, calculates the crc32 of the output from the former step, |
| * and, if necessary, convert and store the output to the writeback buffer. |
| */ |
| static void blend(struct vkms_writeback_job *wb, |
| struct vkms_crtc_state *crtc_state, |
| u32 *crc32, struct line_buffer *stage_buffer, |
| struct line_buffer *output_buffer, size_t row_size) |
| { |
| struct vkms_plane_state **plane = crtc_state->active_planes; |
| u32 n_active_planes = crtc_state->num_active_planes; |
| |
| const struct pixel_argb_u16 background_color = { .a = 0xffff }; |
| |
| size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay; |
| |
| for (size_t y = 0; y < crtc_y_limit; y++) { |
| fill_background(&background_color, output_buffer); |
| |
| /* The active planes are composed associatively in z-order. */ |
| for (size_t i = 0; i < n_active_planes; i++) { |
| if (!check_y_limit(plane[i]->frame_info, y)) |
| continue; |
| |
| plane[i]->plane_read(stage_buffer, plane[i]->frame_info, y); |
| pre_mul_alpha_blend(plane[i]->frame_info, stage_buffer, |
| output_buffer); |
| } |
| |
| *crc32 = crc32_le(*crc32, (void *)output_buffer->pixels, row_size); |
| |
| if (wb) |
| wb->wb_write(&wb->wb_frame_info, output_buffer, y); |
| } |
| } |
| |
| static int check_format_funcs(struct vkms_crtc_state *crtc_state, |
| struct vkms_writeback_job *active_wb) |
| { |
| struct vkms_plane_state **planes = crtc_state->active_planes; |
| u32 n_active_planes = crtc_state->num_active_planes; |
| |
| for (size_t i = 0; i < n_active_planes; i++) |
| if (!planes[i]->plane_read) |
| return -1; |
| |
| if (active_wb && !active_wb->wb_write) |
| return -1; |
| |
| return 0; |
| } |
| |
| static int check_iosys_map(struct vkms_crtc_state *crtc_state) |
| { |
| struct vkms_plane_state **plane_state = crtc_state->active_planes; |
| u32 n_active_planes = crtc_state->num_active_planes; |
| |
| for (size_t i = 0; i < n_active_planes; i++) |
| if (iosys_map_is_null(&plane_state[i]->frame_info->map[0])) |
| return -1; |
| |
| return 0; |
| } |
| |
| static int compose_active_planes(struct vkms_writeback_job *active_wb, |
| struct vkms_crtc_state *crtc_state, |
| u32 *crc32) |
| { |
| size_t line_width, pixel_size = sizeof(struct pixel_argb_u16); |
| struct line_buffer output_buffer, stage_buffer; |
| int ret = 0; |
| |
| /* |
| * This check exists so we can call `crc32_le` for the entire line |
| * instead doing it for each channel of each pixel in case |
| * `struct `pixel_argb_u16` had any gap added by the compiler |
| * between the struct fields. |
| */ |
| static_assert(sizeof(struct pixel_argb_u16) == 8); |
| |
| if (WARN_ON(check_iosys_map(crtc_state))) |
| return -EINVAL; |
| |
| if (WARN_ON(check_format_funcs(crtc_state, active_wb))) |
| return -EINVAL; |
| |
| line_width = crtc_state->base.crtc->mode.hdisplay; |
| stage_buffer.n_pixels = line_width; |
| output_buffer.n_pixels = line_width; |
| |
| stage_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL); |
| if (!stage_buffer.pixels) { |
| DRM_ERROR("Cannot allocate memory for the output line buffer"); |
| return -ENOMEM; |
| } |
| |
| output_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL); |
| if (!output_buffer.pixels) { |
| DRM_ERROR("Cannot allocate memory for intermediate line buffer"); |
| ret = -ENOMEM; |
| goto free_stage_buffer; |
| } |
| |
| blend(active_wb, crtc_state, crc32, &stage_buffer, |
| &output_buffer, line_width * pixel_size); |
| |
| kvfree(output_buffer.pixels); |
| free_stage_buffer: |
| kvfree(stage_buffer.pixels); |
| |
| return ret; |
| } |
| |
| /** |
| * 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 |
| * vkms_vblank_simulate() and flushed at vkms_atomic_commit_tail(). |
| */ |
| 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_writeback_job *active_wb = crtc_state->active_writeback; |
| struct vkms_output *out = drm_crtc_to_vkms_output(crtc); |
| bool crc_pending, wb_pending; |
| u64 frame_start, frame_end; |
| u32 crc32 = 0; |
| 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 (wb_pending) |
| ret = compose_active_planes(active_wb, crtc_state, &crc32); |
| else |
| ret = compose_active_planes(NULL, crtc_state, &crc32); |
| |
| if (ret) |
| return; |
| |
| 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); |
| } |
| |
| /* |
| * 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; |
| } |