drivers/gpu/drm/udl/udl_modeset.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Red Hat
   4  *
   5  * based in parts on udlfb.c:
   6  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
   7  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
   8  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
   9  */
  10
  11 #include <drm/drm_atomic_helper.h>
  12 #include <drm/drm_crtc_helper.h>
  13 #include <drm/drm_damage_helper.h>
  14 #include <drm/drm_fourcc.h>
  15 #include <drm/drm_gem_atomic_helper.h>
  16 #include <drm/drm_gem_framebuffer_helper.h>
  17 #include <drm/drm_gem_shmem_helper.h>
  18 #include <drm/drm_modeset_helper_vtables.h>
  19 #include <drm/drm_vblank.h>
  20
  21 #include "udl_drv.h"
  22
  23 #define UDL_COLOR_DEPTH_16BPP   0
  24
  25 /*
  26  * All DisplayLink bulk operations start with 0xAF, followed by specific code
  27  * All operations are written to buffers which then later get sent to device
  28  */
  29 static char *udl_set_register(char *buf, u8 reg, u8 val)
  30 {
  31         *buf++ = 0xAF;
  32         *buf++ = 0x20;
  33         *buf++ = reg;
  34         *buf++ = val;
  35         return buf;
  36 }
  37
  38 static char *udl_vidreg_lock(char *buf)
  39 {
  40         return udl_set_register(buf, 0xFF, 0x00);
  41 }
  42
  43 static char *udl_vidreg_unlock(char *buf)
  44 {
  45         return udl_set_register(buf, 0xFF, 0xFF);
  46 }
  47
  48 static char *udl_set_blank_mode(char *buf, u8 mode)
  49 {
  50         return udl_set_register(buf, UDL_REG_BLANK_MODE, mode);
  51 }
  52
  53 static char *udl_set_color_depth(char *buf, u8 selection)
  54 {
  55         return udl_set_register(buf, 0x00, selection);
  56 }
  57
  58 static char *udl_set_base16bpp(char *wrptr, u32 base)
  59 {
  60         /* the base pointer is 16 bits wide, 0x20 is hi byte. */
  61         wrptr = udl_set_register(wrptr, 0x20, base >> 16);
  62         wrptr = udl_set_register(wrptr, 0x21, base >> 8);
  63         return udl_set_register(wrptr, 0x22, base);
  64 }
  65
  66 /*
  67  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
  68  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
  69  */
  70 static char *udl_set_base8bpp(char *wrptr, u32 base)
  71 {
  72         wrptr = udl_set_register(wrptr, 0x26, base >> 16);
  73         wrptr = udl_set_register(wrptr, 0x27, base >> 8);
  74         return udl_set_register(wrptr, 0x28, base);
  75 }
  76
  77 static char *udl_set_register_16(char *wrptr, u8 reg, u16 value)
  78 {
  79         wrptr = udl_set_register(wrptr, reg, value >> 8);
  80         return udl_set_register(wrptr, reg+1, value);
  81 }
  82
  83 /*
  84  * This is kind of weird because the controller takes some
  85  * register values in a different byte order than other registers.
  86  */
  87 static char *udl_set_register_16be(char *wrptr, u8 reg, u16 value)
  88 {
  89         wrptr = udl_set_register(wrptr, reg, value);
  90         return udl_set_register(wrptr, reg+1, value >> 8);
  91 }
  92
  93 /*
  94  * LFSR is linear feedback shift register. The reason we have this is
  95  * because the display controller needs to minimize the clock depth of
  96  * various counters used in the display path. So this code reverses the
  97  * provided value into the lfsr16 value by counting backwards to get
  98  * the value that needs to be set in the hardware comparator to get the
  99  * same actual count. This makes sense once you read above a couple of
 100  * times and think about it from a hardware perspective.
 101  */
 102 static u16 udl_lfsr16(u16 actual_count)
 103 {
 104         u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
 105
 106         while (actual_count--) {
 107                 lv =     ((lv << 1) |
 108                         (((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
 109                         & 0xFFFF;
 110         }
 111
 112         return (u16) lv;
 113 }
 114
 115 /*
 116  * This does LFSR conversion on the value that is to be written.
 117  * See LFSR explanation above for more detail.
 118  */
 119 static char *udl_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
 120 {
 121         return udl_set_register_16(wrptr, reg, udl_lfsr16(value));
 122 }
 123
 124 /*
 125  * This takes a standard fbdev screeninfo struct and all of its monitor mode
 126  * details and converts them into the DisplayLink equivalent register commands.
 127   ERR(vreg(dev,               0x00, (color_depth == 16) ? 0 : 1));
 128   ERR(vreg_lfsr16(dev,        0x01, xDisplayStart));
 129   ERR(vreg_lfsr16(dev,        0x03, xDisplayEnd));
 130   ERR(vreg_lfsr16(dev,        0x05, yDisplayStart));
 131   ERR(vreg_lfsr16(dev,        0x07, yDisplayEnd));
 132   ERR(vreg_lfsr16(dev,        0x09, xEndCount));
 133   ERR(vreg_lfsr16(dev,        0x0B, hSyncStart));
 134   ERR(vreg_lfsr16(dev,        0x0D, hSyncEnd));
 135   ERR(vreg_big_endian(dev,    0x0F, hPixels));
 136   ERR(vreg_lfsr16(dev,        0x11, yEndCount));
 137   ERR(vreg_lfsr16(dev,        0x13, vSyncStart));
 138   ERR(vreg_lfsr16(dev,        0x15, vSyncEnd));
 139   ERR(vreg_big_endian(dev,    0x17, vPixels));
 140   ERR(vreg_little_endian(dev, 0x1B, pixelClock5KHz));
 141
 142   ERR(vreg(dev,               0x1F, 0));
 143
 144   ERR(vbuf(dev, WRITE_VIDREG_UNLOCK, DSIZEOF(WRITE_VIDREG_UNLOCK)));
 145  */
 146 static char *udl_set_vid_cmds(char *wrptr, struct drm_display_mode *mode)
 147 {
 148         u16 xds, yds;
 149         u16 xde, yde;
 150         u16 yec;
 151
 152         /* x display start */
 153         xds = mode->crtc_htotal - mode->crtc_hsync_start;
 154         wrptr = udl_set_register_lfsr16(wrptr, 0x01, xds);
 155         /* x display end */
 156         xde = xds + mode->crtc_hdisplay;
 157         wrptr = udl_set_register_lfsr16(wrptr, 0x03, xde);
 158
 159         /* y display start */
 160         yds = mode->crtc_vtotal - mode->crtc_vsync_start;
 161         wrptr = udl_set_register_lfsr16(wrptr, 0x05, yds);
 162         /* y display end */
 163         yde = yds + mode->crtc_vdisplay;
 164         wrptr = udl_set_register_lfsr16(wrptr, 0x07, yde);
 165
 166         /* x end count is active + blanking - 1 */
 167         wrptr = udl_set_register_lfsr16(wrptr, 0x09,
 168                                         mode->crtc_htotal - 1);
 169
 170         /* libdlo hardcodes hsync start to 1 */
 171         wrptr = udl_set_register_lfsr16(wrptr, 0x0B, 1);
 172
 173         /* hsync end is width of sync pulse + 1 */
 174         wrptr = udl_set_register_lfsr16(wrptr, 0x0D,
 175                                         mode->crtc_hsync_end - mode->crtc_hsync_start + 1);
 176
 177         /* hpixels is active pixels */
 178         wrptr = udl_set_register_16(wrptr, 0x0F, mode->hdisplay);
 179
 180         /* yendcount is vertical active + vertical blanking */
 181         yec = mode->crtc_vtotal;
 182         wrptr = udl_set_register_lfsr16(wrptr, 0x11, yec);
 183
 184         /* libdlo hardcodes vsync start to 0 */
 185         wrptr = udl_set_register_lfsr16(wrptr, 0x13, 0);
 186
 187         /* vsync end is width of vsync pulse */
 188         wrptr = udl_set_register_lfsr16(wrptr, 0x15, mode->crtc_vsync_end - mode->crtc_vsync_start);
 189
 190         /* vpixels is active pixels */
 191         wrptr = udl_set_register_16(wrptr, 0x17, mode->crtc_vdisplay);
 192
 193         wrptr = udl_set_register_16be(wrptr, 0x1B,
 194                                       mode->clock / 5);
 195
 196         return wrptr;
 197 }
 198
 199 static char *udl_dummy_render(char *wrptr)
 200 {
 201         *wrptr++ = 0xAF;
 202         *wrptr++ = 0x6A; /* copy */
 203         *wrptr++ = 0x00; /* from addr */
 204         *wrptr++ = 0x00;
 205         *wrptr++ = 0x00;
 206         *wrptr++ = 0x01; /* one pixel */
 207         *wrptr++ = 0x00; /* to address */
 208         *wrptr++ = 0x00;
 209         *wrptr++ = 0x00;
 210         return wrptr;
 211 }
 212
 213 static int udl_crtc_write_mode_to_hw(struct drm_crtc *crtc)
 214 {
 215         struct drm_device *dev = crtc->dev;
 216         struct udl_device *udl = to_udl(dev);
 217         struct urb *urb;
 218         char *buf;
 219         int retval;
 220
 221         if (udl->mode_buf_len == 0) {
 222                 DRM_ERROR("No mode set\n");
 223                 return -EINVAL;
 224         }
 225
 226         urb = udl_get_urb(dev);
 227         if (!urb)
 228                 return -ENOMEM;
 229
 230         buf = (char *)urb->transfer_buffer;
 231
 232         memcpy(buf, udl->mode_buf, udl->mode_buf_len);
 233         retval = udl_submit_urb(dev, urb, udl->mode_buf_len);
 234         DRM_DEBUG("write mode info %d\n", udl->mode_buf_len);
 235         return retval;
 236 }
 237
 238 static long udl_log_cpp(unsigned int cpp)
 239 {
 240         if (WARN_ON(!is_power_of_2(cpp)))
 241                 return -EINVAL;
 242         return __ffs(cpp);
 243 }
 244
 245 static int udl_aligned_damage_clip(struct drm_rect *clip, int x, int y,
 246                                    int width, int height)
 247 {
 248         int x1, x2;
 249
 250         if (WARN_ON_ONCE(x < 0) ||
 251             WARN_ON_ONCE(y < 0) ||
 252             WARN_ON_ONCE(width < 0) ||
 253             WARN_ON_ONCE(height < 0))
 254                 return -EINVAL;
 255
 256         x1 = ALIGN_DOWN(x, sizeof(unsigned long));
 257         x2 = ALIGN(width + (x - x1), sizeof(unsigned long)) + x1;
 258
 259         clip->x1 = x1;
 260         clip->y1 = y;
 261         clip->x2 = x2;
 262         clip->y2 = y + height;
 263
 264         return 0;
 265 }
 266
 267 static int udl_handle_damage(struct drm_framebuffer *fb, const struct dma_buf_map *map,
 268                              int x, int y, int width, int height)
 269 {
 270         struct drm_device *dev = fb->dev;
 271         void *vaddr = map->vaddr; /* TODO: Use mapping abstraction properly */
 272         int i, ret;
 273         char *cmd;
 274         struct urb *urb;
 275         struct drm_rect clip;
 276         int log_bpp;
 277
 278         ret = udl_log_cpp(fb->format->cpp[0]);
 279         if (ret < 0)
 280                 return ret;
 281         log_bpp = ret;
 282
 283         ret = udl_aligned_damage_clip(&clip, x, y, width, height);
 284         if (ret)
 285                 return ret;
 286         else if ((clip.x2 > fb->width) || (clip.y2 > fb->height))
 287                 return -EINVAL;
 288
 289         ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
 290         if (ret)
 291                 return ret;
 292
 293         urb = udl_get_urb(dev);
 294         if (!urb) {
 295                 ret = -ENOMEM;
 296                 goto out_drm_gem_fb_end_cpu_access;
 297         }
 298         cmd = urb->transfer_buffer;
 299
 300         for (i = clip.y1; i < clip.y2; i++) {
 301                 const int line_offset = fb->pitches[0] * i;
 302                 const int byte_offset = line_offset + (clip.x1 << log_bpp);
 303                 const int dev_byte_offset = (fb->width * i + clip.x1) << log_bpp;
 304                 const int byte_width = (clip.x2 - clip.x1) << log_bpp;
 305                 ret = udl_render_hline(dev, log_bpp, &urb, (char *)vaddr,
 306                                        &cmd, byte_offset, dev_byte_offset,
 307                                        byte_width);
 308                 if (ret)
 309                         goto out_drm_gem_fb_end_cpu_access;
 310         }
 311
 312         if (cmd > (char *)urb->transfer_buffer) {
 313                 /* Send partial buffer remaining before exiting */
 314                 int len;
 315                 if (cmd < (char *)urb->transfer_buffer + urb->transfer_buffer_length)
 316                         *cmd++ = 0xAF;
 317                 len = cmd - (char *)urb->transfer_buffer;
 318                 ret = udl_submit_urb(dev, urb, len);
 319         } else {
 320                 udl_urb_completion(urb);
 321         }
 322
 323         ret = 0;
 324
 325 out_drm_gem_fb_end_cpu_access:
 326         drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
 327         return ret;
 328 }
 329
 330 /*
 331  * Simple display pipeline
 332  */
 333
 334 static const uint32_t udl_simple_display_pipe_formats[] = {
 335         DRM_FORMAT_RGB565,
 336         DRM_FORMAT_XRGB8888,
 337 };
 338
 339 static enum drm_mode_status
 340 udl_simple_display_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
 341                                    const struct drm_display_mode *mode)
 342 {
 343         return MODE_OK;
 344 }
 345
 346 static void
 347 udl_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
 348                                struct drm_crtc_state *crtc_state,
 349                                struct drm_plane_state *plane_state)
 350 {
 351         struct drm_crtc *crtc = &pipe->crtc;
 352         struct drm_device *dev = crtc->dev;
 353         struct drm_framebuffer *fb = plane_state->fb;
 354         struct udl_device *udl = to_udl(dev);
 355         struct drm_display_mode *mode = &crtc_state->mode;
 356         struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 357         char *buf;
 358         char *wrptr;
 359         int color_depth = UDL_COLOR_DEPTH_16BPP;
 360
 361         buf = (char *)udl->mode_buf;
 362
 363         /* This first section has to do with setting the base address on the
 364          * controller associated with the display. There are 2 base
 365          * pointers, currently, we only use the 16 bpp segment.
 366          */
 367         wrptr = udl_vidreg_lock(buf);
 368         wrptr = udl_set_color_depth(wrptr, color_depth);
 369         /* set base for 16bpp segment to 0 */
 370         wrptr = udl_set_base16bpp(wrptr, 0);
 371         /* set base for 8bpp segment to end of fb */
 372         wrptr = udl_set_base8bpp(wrptr, 2 * mode->vdisplay * mode->hdisplay);
 373
 374         wrptr = udl_set_vid_cmds(wrptr, mode);
 375         wrptr = udl_set_blank_mode(wrptr, UDL_BLANK_MODE_ON);
 376         wrptr = udl_vidreg_unlock(wrptr);
 377
 378         wrptr = udl_dummy_render(wrptr);
 379
 380         udl->mode_buf_len = wrptr - buf;
 381
 382         udl_handle_damage(fb, &shadow_plane_state->data[0], 0, 0, fb->width, fb->height);
 383
 384         if (!crtc_state->mode_changed)
 385                 return;
 386
 387         /* enable display */
 388         udl_crtc_write_mode_to_hw(crtc);
 389 }
 390
 391 static void
 392 udl_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
 393 {
 394         struct drm_crtc *crtc = &pipe->crtc;
 395         struct drm_device *dev = crtc->dev;
 396         struct urb *urb;
 397         char *buf;
 398
 399         urb = udl_get_urb(dev);
 400         if (!urb)
 401                 return;
 402
 403         buf = (char *)urb->transfer_buffer;
 404         buf = udl_vidreg_lock(buf);
 405         buf = udl_set_blank_mode(buf, UDL_BLANK_MODE_POWERDOWN);
 406         buf = udl_vidreg_unlock(buf);
 407         buf = udl_dummy_render(buf);
 408
 409         udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
 410 }
 411
 412 static void
 413 udl_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
 414                                struct drm_plane_state *old_plane_state)
 415 {
 416         struct drm_plane_state *state = pipe->plane.state;
 417         struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
 418         struct drm_framebuffer *fb = state->fb;
 419         struct drm_rect rect;
 420
 421         if (!fb)
 422                 return;
 423
 424         if (drm_atomic_helper_damage_merged(old_plane_state, state, &rect))
 425                 udl_handle_damage(fb, &shadow_plane_state->data[0], rect.x1, rect.y1,
 426                                   rect.x2 - rect.x1, rect.y2 - rect.y1);
 427 }
 428
 429 static const struct drm_simple_display_pipe_funcs udl_simple_display_pipe_funcs = {
 430         .mode_valid = udl_simple_display_pipe_mode_valid,
 431         .enable = udl_simple_display_pipe_enable,
 432         .disable = udl_simple_display_pipe_disable,
 433         .update = udl_simple_display_pipe_update,
 434         DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
 435 };
 436
 437 /*
 438  * Modesetting
 439  */
 440
 441 static const struct drm_mode_config_funcs udl_mode_funcs = {
 442         .fb_create = drm_gem_fb_create_with_dirty,
 443         .atomic_check  = drm_atomic_helper_check,
 444         .atomic_commit = drm_atomic_helper_commit,
 445 };
 446
 447 int udl_modeset_init(struct drm_device *dev)
 448 {
 449         size_t format_count = ARRAY_SIZE(udl_simple_display_pipe_formats);
 450         struct udl_device *udl = to_udl(dev);
 451         struct drm_connector *connector;
 452         int ret;
 453
 454         ret = drmm_mode_config_init(dev);
 455         if (ret)
 456                 return ret;
 457
 458         dev->mode_config.min_width = 640;
 459         dev->mode_config.min_height = 480;
 460
 461         dev->mode_config.max_width = 2048;
 462         dev->mode_config.max_height = 2048;
 463
 464         dev->mode_config.prefer_shadow = 0;
 465         dev->mode_config.preferred_depth = 16;
 466
 467         dev->mode_config.funcs = &udl_mode_funcs;
 468
 469         connector = udl_connector_init(dev);
 470         if (IS_ERR(connector))
 471                 return PTR_ERR(connector);
 472
 473         format_count = ARRAY_SIZE(udl_simple_display_pipe_formats);
 474
 475         ret = drm_simple_display_pipe_init(dev, &udl->display_pipe,
 476                                            &udl_simple_display_pipe_funcs,
 477                                            udl_simple_display_pipe_formats,
 478                                            format_count, NULL, connector);
 479         if (ret)
 480                 return ret;
 481
 482         drm_mode_config_reset(dev);
 483
 484         return 0;
 485 }