drivers/gpu/drm/vkms/vkms_composer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2
   3 #include <linux/crc32.h>
   4
   5 #include <drm/drm_atomic.h>
   6 #include <drm/drm_atomic_helper.h>
   7 #include <drm/drm_gem_framebuffer_helper.h>
   8 #include <drm/drm_vblank.h>
   9
  10 #include "vkms_drv.h"
  11
  12 static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
  13                                  const struct vkms_composer *composer)
  14 {
  15         u32 pixel;
  16         int src_offset = composer->offset + (y * composer->pitch)
  17                                       + (x * composer->cpp);
  18
  19         pixel = *(u32 *)&buffer[src_offset];
  20
  21         return pixel;
  22 }
  23
  24 /**
  25  * compute_crc - Compute CRC value on output frame
  26  *
  27  * @vaddr: address to final framebuffer
  28  * @composer: framebuffer's metadata
  29  *
  30  * returns CRC value computed using crc32 on the visible portion of
  31  * the final framebuffer at vaddr_out
  32  */
  33 static uint32_t compute_crc(const u8 *vaddr,
  34                             const struct vkms_composer *composer)
  35 {
  36         int x, y;
  37         u32 crc = 0, pixel = 0;
  38         int x_src = composer->src.x1 >> 16;
  39         int y_src = composer->src.y1 >> 16;
  40         int h_src = drm_rect_height(&composer->src) >> 16;
  41         int w_src = drm_rect_width(&composer->src) >> 16;
  42
  43         for (y = y_src; y < y_src + h_src; ++y) {
  44                 for (x = x_src; x < x_src + w_src; ++x) {
  45                         pixel = get_pixel_from_buffer(x, y, vaddr, composer);
  46                         crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
  47                 }
  48         }
  49
  50         return crc;
  51 }
  52
  53 static u8 blend_channel(u8 src, u8 dst, u8 alpha)
  54 {
  55         u32 pre_blend;
  56         u8 new_color;
  57
  58         pre_blend = (src * 255 + dst * (255 - alpha));
  59
  60         /* Faster div by 255 */
  61         new_color = ((pre_blend + ((pre_blend + 257) >> 8)) >> 8);
  62
  63         return new_color;
  64 }
  65
  66 static void alpha_blending(const u8 *argb_src, u8 *argb_dst)
  67 {
  68         u8 alpha;
  69
  70         alpha = argb_src[3];
  71         argb_dst[0] = blend_channel(argb_src[0], argb_dst[0], alpha);
  72         argb_dst[1] = blend_channel(argb_src[1], argb_dst[1], alpha);
  73         argb_dst[2] = blend_channel(argb_src[2], argb_dst[2], alpha);
  74         /* Opaque primary */
  75         argb_dst[3] = 0xFF;
  76 }
  77
  78 /**
  79  * blend - blend value at vaddr_src with value at vaddr_dst
  80  * @vaddr_dst: destination address
  81  * @vaddr_src: source address
  82  * @dst_composer: destination framebuffer's metadata
  83  * @src_composer: source framebuffer's metadata
  84  *
  85  * Blend the vaddr_src value with the vaddr_dst value using the pre-multiplied
  86  * alpha blending equation, since DRM currently assumes that the pixel color
  87  * values have already been pre-multiplied with the alpha channel values. See
  88  * more drm_plane_create_blend_mode_property(). This function uses buffer's
  89  * metadata to locate the new composite values at vaddr_dst.
  90  */
  91 static void blend(void *vaddr_dst, void *vaddr_src,
  92                   struct vkms_composer *dst_composer,
  93                   struct vkms_composer *src_composer)
  94 {
  95         int i, j, j_dst, i_dst;
  96         int offset_src, offset_dst;
  97         u8 *pixel_dst, *pixel_src;
  98
  99         int x_src = src_composer->src.x1 >> 16;
 100         int y_src = src_composer->src.y1 >> 16;
 101
 102         int x_dst = src_composer->dst.x1;
 103         int y_dst = src_composer->dst.y1;
 104         int h_dst = drm_rect_height(&src_composer->dst);
 105         int w_dst = drm_rect_width(&src_composer->dst);
 106
 107         int y_limit = y_src + h_dst;
 108         int x_limit = x_src + w_dst;
 109
 110         for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
 111                 for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
 112                         offset_dst = dst_composer->offset
 113                                      + (i_dst * dst_composer->pitch)
 114                                      + (j_dst++ * dst_composer->cpp);
 115                         offset_src = src_composer->offset
 116                                      + (i * src_composer->pitch)
 117                                      + (j * src_composer->cpp);
 118
 119                         pixel_src = (u8 *)(vaddr_src + offset_src);
 120                         pixel_dst = (u8 *)(vaddr_dst + offset_dst);
 121                         alpha_blending(pixel_src, pixel_dst);
 122                 }
 123                 i_dst++;
 124         }
 125 }
 126
 127 static void compose_cursor(struct vkms_composer *cursor_composer,
 128                            struct vkms_composer *primary_composer,
 129                            void *vaddr_out)
 130 {
 131         struct drm_gem_object *cursor_obj;
 132         struct vkms_gem_object *cursor_vkms_obj;
 133
 134         cursor_obj = drm_gem_fb_get_obj(&cursor_composer->fb, 0);
 135         cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
 136
 137         if (WARN_ON(!cursor_vkms_obj->vaddr))
 138                 return;
 139
 140         blend(vaddr_out, cursor_vkms_obj->vaddr,
 141               primary_composer, cursor_composer);
 142 }
 143
 144 static int compose_planes(void **vaddr_out,
 145                           struct vkms_composer *primary_composer,
 146                           struct vkms_composer *cursor_composer)
 147 {
 148         struct drm_framebuffer *fb = &primary_composer->fb;
 149         struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
 150         struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj);
 151
 152         if (!*vaddr_out) {
 153                 *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
 154                 if (!*vaddr_out) {
 155                         DRM_ERROR("Cannot allocate memory for output frame.");
 156                         return -ENOMEM;
 157                 }
 158         }
 159
 160         if (WARN_ON(!vkms_obj->vaddr))
 161                 return -EINVAL;
 162
 163         memcpy(*vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
 164
 165         if (cursor_composer)
 166                 compose_cursor(cursor_composer, primary_composer, *vaddr_out);
 167
 168         return 0;
 169 }
 170
 171 /**
 172  * vkms_composer_worker - ordered work_struct to compute CRC
 173  *
 174  * @work: work_struct
 175  *
 176  * Work handler for composing and computing CRCs. work_struct scheduled in
 177  * an ordered workqueue that's periodically scheduled to run by
 178  * _vblank_handle() and flushed at vkms_atomic_crtc_destroy_state().
 179  */
 180 void vkms_composer_worker(struct work_struct *work)
 181 {
 182         struct vkms_crtc_state *crtc_state = container_of(work,
 183                                                 struct vkms_crtc_state,
 184                                                 composer_work);
 185         struct drm_crtc *crtc = crtc_state->base.crtc;
 186         struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 187         struct vkms_composer *primary_composer = NULL;
 188         struct vkms_composer *cursor_composer = NULL;
 189         bool crc_pending, wb_pending;
 190         void *vaddr_out = NULL;
 191         u32 crc32 = 0;
 192         u64 frame_start, frame_end;
 193         int ret;
 194
 195         spin_lock_irq(&out->composer_lock);
 196         frame_start = crtc_state->frame_start;
 197         frame_end = crtc_state->frame_end;
 198         crc_pending = crtc_state->crc_pending;
 199         wb_pending = crtc_state->wb_pending;
 200         crtc_state->frame_start = 0;
 201         crtc_state->frame_end = 0;
 202         crtc_state->crc_pending = false;
 203         spin_unlock_irq(&out->composer_lock);
 204
 205         /*
 206          * We raced with the vblank hrtimer and previous work already computed
 207          * the crc, nothing to do.
 208          */
 209         if (!crc_pending)
 210                 return;
 211
 212         if (crtc_state->num_active_planes >= 1)
 213                 primary_composer = crtc_state->active_planes[0]->composer;
 214
 215         if (crtc_state->num_active_planes == 2)
 216                 cursor_composer = crtc_state->active_planes[1]->composer;
 217
 218         if (!primary_composer)
 219                 return;
 220
 221         if (wb_pending)
 222                 vaddr_out = crtc_state->active_writeback;
 223
 224         ret = compose_planes(&vaddr_out, primary_composer, cursor_composer);
 225         if (ret) {
 226                 if (ret == -EINVAL && !wb_pending)
 227                         kfree(vaddr_out);
 228                 return;
 229         }
 230
 231         crc32 = compute_crc(vaddr_out, primary_composer);
 232
 233         if (wb_pending) {
 234                 drm_writeback_signal_completion(&out->wb_connector, 0);
 235                 spin_lock_irq(&out->composer_lock);
 236                 crtc_state->wb_pending = false;
 237                 spin_unlock_irq(&out->composer_lock);
 238         } else {
 239                 kfree(vaddr_out);
 240         }
 241
 242         /*
 243          * The worker can fall behind the vblank hrtimer, make sure we catch up.
 244          */
 245         while (frame_start <= frame_end)
 246                 drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
 247 }
 248
 249 static const char * const pipe_crc_sources[] = {"auto"};
 250
 251 const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
 252                                         size_t *count)
 253 {
 254         *count = ARRAY_SIZE(pipe_crc_sources);
 255         return pipe_crc_sources;
 256 }
 257
 258 static int vkms_crc_parse_source(const char *src_name, bool *enabled)
 259 {
 260         int ret = 0;
 261
 262         if (!src_name) {
 263                 *enabled = false;
 264         } else if (strcmp(src_name, "auto") == 0) {
 265                 *enabled = true;
 266         } else {
 267                 *enabled = false;
 268                 ret = -EINVAL;
 269         }
 270
 271         return ret;
 272 }
 273
 274 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
 275                            size_t *values_cnt)
 276 {
 277         bool enabled;
 278
 279         if (vkms_crc_parse_source(src_name, &enabled) < 0) {
 280                 DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
 281                 return -EINVAL;
 282         }
 283
 284         *values_cnt = 1;
 285
 286         return 0;
 287 }
 288
 289 void vkms_set_composer(struct vkms_output *out, bool enabled)
 290 {
 291         bool old_enabled;
 292
 293         if (enabled)
 294                 drm_crtc_vblank_get(&out->crtc);
 295
 296         spin_lock_irq(&out->lock);
 297         old_enabled = out->composer_enabled;
 298         out->composer_enabled = enabled;
 299         spin_unlock_irq(&out->lock);
 300
 301         if (old_enabled)
 302                 drm_crtc_vblank_put(&out->crtc);
 303 }
 304
 305 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
 306 {
 307         struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 308         bool enabled = false;
 309         int ret = 0;
 310
 311         ret = vkms_crc_parse_source(src_name, &enabled);
 312
 313         vkms_set_composer(out, enabled);
 314
 315         return ret;
 316 }