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_gem_shmem_helper.h>
   9 #include <drm/drm_vblank.h>
  10
  11 #include "vkms_drv.h"
  12
  13 static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
  14                                  const struct vkms_composer *composer)
  15 {
  16         u32 pixel;
  17         int src_offset = composer->offset + (y * composer->pitch)
  18                                       + (x * composer->cpp);
  19
  20         pixel = *(u32 *)&buffer[src_offset];
  21
  22         return pixel;
  23 }
  24
  25 /**
  26  * compute_crc - Compute CRC value on output frame
  27  *
  28  * @vaddr: address to final framebuffer
  29  * @composer: framebuffer's metadata
  30  *
  31  * returns CRC value computed using crc32 on the visible portion of
  32  * the final framebuffer at vaddr_out
  33  */
  34 static uint32_t compute_crc(const u8 *vaddr,
  35                             const struct vkms_composer *composer)
  36 {
  37         int x, y;
  38         u32 crc = 0, pixel = 0;
  39         int x_src = composer->src.x1 >> 16;
  40         int y_src = composer->src.y1 >> 16;
  41         int h_src = drm_rect_height(&composer->src) >> 16;
  42         int w_src = drm_rect_width(&composer->src) >> 16;
  43
  44         for (y = y_src; y < y_src + h_src; ++y) {
  45                 for (x = x_src; x < x_src + w_src; ++x) {
  46                         pixel = get_pixel_from_buffer(x, y, vaddr, composer);
  47                         crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
  48                 }
  49         }
  50
  51         return crc;
  52 }
  53
  54 static u8 blend_channel(u8 src, u8 dst, u8 alpha)
  55 {
  56         u32 pre_blend;
  57         u8 new_color;
  58
  59         pre_blend = (src * 255 + dst * (255 - alpha));
  60
  61         /* Faster div by 255 */
  62         new_color = ((pre_blend + ((pre_blend + 257) >> 8)) >> 8);
  63
  64         return new_color;
  65 }
  66
  67 static void alpha_blending(const u8 *argb_src, u8 *argb_dst)
  68 {
  69         u8 alpha;
  70
  71         alpha = argb_src[3];
  72         argb_dst[0] = blend_channel(argb_src[0], argb_dst[0], alpha);
  73         argb_dst[1] = blend_channel(argb_src[1], argb_dst[1], alpha);
  74         argb_dst[2] = blend_channel(argb_src[2], argb_dst[2], alpha);
  75         /* Opaque primary */
  76         argb_dst[3] = 0xFF;
  77 }
  78
  79 /**
  80  * blend - blend value at vaddr_src with value at vaddr_dst
  81  * @vaddr_dst: destination address
  82  * @vaddr_src: source address
  83  * @dst_composer: destination framebuffer's metadata
  84  * @src_composer: source framebuffer's metadata
  85  *
  86  * Blend the vaddr_src value with the vaddr_dst value using the pre-multiplied
  87  * alpha blending equation, since DRM currently assumes that the pixel color
  88  * values have already been pre-multiplied with the alpha channel values. See
  89  * more drm_plane_create_blend_mode_property(). This function uses buffer's
  90  * metadata to locate the new composite values at vaddr_dst.
  91  */
  92 static void blend(void *vaddr_dst, void *vaddr_src,
  93                   struct vkms_composer *dst_composer,
  94                   struct vkms_composer *src_composer)
  95 {
  96         int i, j, j_dst, i_dst;
  97         int offset_src, offset_dst;
  98         u8 *pixel_dst, *pixel_src;
  99
 100         int x_src = src_composer->src.x1 >> 16;
 101         int y_src = src_composer->src.y1 >> 16;
 102
 103         int x_dst = src_composer->dst.x1;
 104         int y_dst = src_composer->dst.y1;
 105         int h_dst = drm_rect_height(&src_composer->dst);
 106         int w_dst = drm_rect_width(&src_composer->dst);
 107
 108         int y_limit = y_src + h_dst;
 109         int x_limit = x_src + w_dst;
 110
 111         for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
 112                 for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
 113                         offset_dst = dst_composer->offset
 114                                      + (i_dst * dst_composer->pitch)
 115                                      + (j_dst++ * dst_composer->cpp);
 116                         offset_src = src_composer->offset
 117                                      + (i * src_composer->pitch)
 118                                      + (j * src_composer->cpp);
 119
 120                         pixel_src = (u8 *)(vaddr_src + offset_src);
 121                         pixel_dst = (u8 *)(vaddr_dst + offset_dst);
 122                         alpha_blending(pixel_src, pixel_dst);
 123                 }
 124                 i_dst++;
 125         }
 126 }
 127
 128 static void compose_cursor(struct vkms_composer *cursor_composer,
 129                            struct vkms_composer *primary_composer,
 130                            void *vaddr_out)
 131 {
 132         struct drm_gem_object *cursor_obj;
 133         struct drm_gem_shmem_object *cursor_shmem_obj;
 134
 135         cursor_obj = drm_gem_fb_get_obj(&cursor_composer->fb, 0);
 136         cursor_shmem_obj = to_drm_gem_shmem_obj(cursor_obj);
 137
 138         if (WARN_ON(!cursor_shmem_obj->vaddr))
 139                 return;
 140
 141         blend(vaddr_out, cursor_shmem_obj->vaddr,
 142               primary_composer, cursor_composer);
 143 }
 144
 145 static int compose_planes(void **vaddr_out,
 146                           struct vkms_composer *primary_composer,
 147                           struct vkms_composer *cursor_composer)
 148 {
 149         struct drm_framebuffer *fb = &primary_composer->fb;
 150         struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
 151         struct drm_gem_shmem_object *shmem_obj = to_drm_gem_shmem_obj(gem_obj);
 152
 153         if (!*vaddr_out) {
 154                 *vaddr_out = kzalloc(shmem_obj->base.size, GFP_KERNEL);
 155                 if (!*vaddr_out) {
 156                         DRM_ERROR("Cannot allocate memory for output frame.");
 157                         return -ENOMEM;
 158                 }
 159         }
 160
 161         if (WARN_ON(!shmem_obj->vaddr))
 162                 return -EINVAL;
 163
 164         memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
 165
 166         if (cursor_composer)
 167                 compose_cursor(cursor_composer, primary_composer, *vaddr_out);
 168
 169         return 0;
 170 }
 171
 172 /**
 173  * vkms_composer_worker - ordered work_struct to compute CRC
 174  *
 175  * @work: work_struct
 176  *
 177  * Work handler for composing and computing CRCs. work_struct scheduled in
 178  * an ordered workqueue that's periodically scheduled to run by
 179  * _vblank_handle() and flushed at vkms_atomic_crtc_destroy_state().
 180  */
 181 void vkms_composer_worker(struct work_struct *work)
 182 {
 183         struct vkms_crtc_state *crtc_state = container_of(work,
 184                                                 struct vkms_crtc_state,
 185                                                 composer_work);
 186         struct drm_crtc *crtc = crtc_state->base.crtc;
 187         struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 188         struct vkms_composer *primary_composer = NULL;
 189         struct vkms_composer *cursor_composer = NULL;
 190         bool crc_pending, wb_pending;
 191         void *vaddr_out = NULL;
 192         u32 crc32 = 0;
 193         u64 frame_start, frame_end;
 194         int ret;
 195
 196         spin_lock_irq(&out->composer_lock);
 197         frame_start = crtc_state->frame_start;
 198         frame_end = crtc_state->frame_end;
 199         crc_pending = crtc_state->crc_pending;
 200         wb_pending = crtc_state->wb_pending;
 201         crtc_state->frame_start = 0;
 202         crtc_state->frame_end = 0;
 203         crtc_state->crc_pending = false;
 204         spin_unlock_irq(&out->composer_lock);
 205
 206         /*
 207          * We raced with the vblank hrtimer and previous work already computed
 208          * the crc, nothing to do.
 209          */
 210         if (!crc_pending)
 211                 return;
 212
 213         if (crtc_state->num_active_planes >= 1)
 214                 primary_composer = crtc_state->active_planes[0]->composer;
 215
 216         if (crtc_state->num_active_planes == 2)
 217                 cursor_composer = crtc_state->active_planes[1]->composer;
 218
 219         if (!primary_composer)
 220                 return;
 221
 222         if (wb_pending)
 223                 vaddr_out = crtc_state->active_writeback;
 224
 225         ret = compose_planes(&vaddr_out, primary_composer, cursor_composer);
 226         if (ret) {
 227                 if (ret == -EINVAL && !wb_pending)
 228                         kfree(vaddr_out);
 229                 return;
 230         }
 231
 232         crc32 = compute_crc(vaddr_out, primary_composer);
 233
 234         if (wb_pending) {
 235                 drm_writeback_signal_completion(&out->wb_connector, 0);
 236                 spin_lock_irq(&out->composer_lock);
 237                 crtc_state->wb_pending = false;
 238                 spin_unlock_irq(&out->composer_lock);
 239         } else {
 240                 kfree(vaddr_out);
 241         }
 242
 243         /*
 244          * The worker can fall behind the vblank hrtimer, make sure we catch up.
 245          */
 246         while (frame_start <= frame_end)
 247                 drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
 248 }
 249
 250 static const char * const pipe_crc_sources[] = {"auto"};
 251
 252 const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
 253                                         size_t *count)
 254 {
 255         *count = ARRAY_SIZE(pipe_crc_sources);
 256         return pipe_crc_sources;
 257 }
 258
 259 static int vkms_crc_parse_source(const char *src_name, bool *enabled)
 260 {
 261         int ret = 0;
 262
 263         if (!src_name) {
 264                 *enabled = false;
 265         } else if (strcmp(src_name, "auto") == 0) {
 266                 *enabled = true;
 267         } else {
 268                 *enabled = false;
 269                 ret = -EINVAL;
 270         }
 271
 272         return ret;
 273 }
 274
 275 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
 276                            size_t *values_cnt)
 277 {
 278         bool enabled;
 279
 280         if (vkms_crc_parse_source(src_name, &enabled) < 0) {
 281                 DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
 282                 return -EINVAL;
 283         }
 284
 285         *values_cnt = 1;
 286
 287         return 0;
 288 }
 289
 290 void vkms_set_composer(struct vkms_output *out, bool enabled)
 291 {
 292         bool old_enabled;
 293
 294         if (enabled)
 295                 drm_crtc_vblank_get(&out->crtc);
 296
 297         spin_lock_irq(&out->lock);
 298         old_enabled = out->composer_enabled;
 299         out->composer_enabled = enabled;
 300         spin_unlock_irq(&out->lock);
 301
 302         if (old_enabled)
 303                 drm_crtc_vblank_put(&out->crtc);
 304 }
 305
 306 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
 307 {
 308         struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
 309         bool enabled = false;
 310         int ret = 0;
 311
 312         ret = vkms_crc_parse_source(src_name, &enabled);
 313
 314         vkms_set_composer(out, enabled);
 315
 316         return ret;
 317 }