drivers/char/drm/via_dmablit.c

   1 /* via_dmablit.c -- PCI DMA BitBlt support for the VIA Unichrome/Pro
   2  *
   3  * Copyright (C) 2005 Thomas Hellstrom, All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sub license,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the
  13  * next paragraph) shall be included in all copies or substantial portions
  14  * of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  19  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  20  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  21  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  22  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Thomas Hellstrom.
  26  *    Partially based on code obtained from Digeo Inc.
  27  */
  28
  29
  30 /*
  31  * Unmaps the DMA mappings.
  32  * FIXME: Is this a NoOp on x86? Also
  33  * FIXME: What happens if this one is called and a pending blit has previously done
  34  * the same DMA mappings?
  35  */
  36
  37 #include "drmP.h"
  38 #include "via_drm.h"
  39 #include "via_drv.h"
  40 #include "via_dmablit.h"
  41
  42 #include <linux/pagemap.h>
  43
  44 #define VIA_PGDN(x)          (((unsigned long)(x)) & PAGE_MASK)
  45 #define VIA_PGOFF(x)        (((unsigned long)(x)) & ~PAGE_MASK)
  46 #define VIA_PFN(x)            ((unsigned long)(x) >> PAGE_SHIFT)
  47
  48 typedef struct _drm_via_descriptor {
  49         uint32_t mem_addr;
  50         uint32_t dev_addr;
  51         uint32_t size;
  52         uint32_t next;
  53 } drm_via_descriptor_t;
  54
  55
  56 /*
  57  * Unmap a DMA mapping.
  58  */
  59
  60
  61
  62 static void
  63 via_unmap_blit_from_device(struct pci_dev *pdev, drm_via_sg_info_t *vsg)
  64 {
  65         int num_desc = vsg->num_desc;
  66         unsigned cur_descriptor_page = num_desc / vsg->descriptors_per_page;
  67         unsigned descriptor_this_page = num_desc % vsg->descriptors_per_page;
  68         drm_via_descriptor_t *desc_ptr = vsg->desc_pages[cur_descriptor_page] +
  69                 descriptor_this_page;
  70         dma_addr_t next = vsg->chain_start;
  71
  72         while(num_desc--) {
  73                 if (descriptor_this_page-- == 0) {
  74                         cur_descriptor_page--;
  75                         descriptor_this_page = vsg->descriptors_per_page - 1;
  76                         desc_ptr = vsg->desc_pages[cur_descriptor_page] +
  77                                 descriptor_this_page;
  78                 }
  79                 dma_unmap_single(&pdev->dev, next, sizeof(*desc_ptr), DMA_TO_DEVICE);
  80                 dma_unmap_page(&pdev->dev, desc_ptr->mem_addr, desc_ptr->size, vsg->direction);
  81                 next = (dma_addr_t) desc_ptr->next;
  82                 desc_ptr--;
  83         }
  84 }
  85
  86 /*
  87  * If mode = 0, count how many descriptors are needed.
  88  * If mode = 1, Map the DMA pages for the device, put together and map also the descriptors.
  89  * Descriptors are run in reverse order by the hardware because we are not allowed to update the
  90  * 'next' field without syncing calls when the descriptor is already mapped.
  91  */
  92
  93 static void
  94 via_map_blit_for_device(struct pci_dev *pdev,
  95                    const drm_via_dmablit_t *xfer,
  96                    drm_via_sg_info_t *vsg,
  97                    int mode)
  98 {
  99         unsigned cur_descriptor_page = 0;
 100         unsigned num_descriptors_this_page = 0;
 101         unsigned char *mem_addr = xfer->mem_addr;
 102         unsigned char *cur_mem;
 103         unsigned char *first_addr = (unsigned char *)VIA_PGDN(mem_addr);
 104         uint32_t fb_addr = xfer->fb_addr;
 105         uint32_t cur_fb;
 106         unsigned long line_len;
 107         unsigned remaining_len;
 108         int num_desc = 0;
 109         int cur_line;
 110         dma_addr_t next = 0 | VIA_DMA_DPR_EC;
 111         drm_via_descriptor_t *desc_ptr = NULL;
 112
 113         if (mode == 1)
 114                 desc_ptr = vsg->desc_pages[cur_descriptor_page];
 115
 116         for (cur_line = 0; cur_line < xfer->num_lines; ++cur_line) {
 117
 118                 line_len = xfer->line_length;
 119                 cur_fb = fb_addr;
 120                 cur_mem = mem_addr;
 121
 122                 while (line_len > 0) {
 123
 124                         remaining_len = min(PAGE_SIZE-VIA_PGOFF(cur_mem), line_len);
 125                         line_len -= remaining_len;
 126
 127                         if (mode == 1) {
 128                                 desc_ptr->mem_addr =
 129                                         dma_map_page(&pdev->dev,
 130                                                      vsg->pages[VIA_PFN(cur_mem) -
 131                                                                 VIA_PFN(first_addr)],
 132                                                      VIA_PGOFF(cur_mem), remaining_len,
 133                                                      vsg->direction);
 134                                 desc_ptr->dev_addr = cur_fb;
 135
 136                                 desc_ptr->size = remaining_len;
 137                                 desc_ptr->next = (uint32_t) next;
 138                                 next = dma_map_single(&pdev->dev, desc_ptr, sizeof(*desc_ptr),
 139                                                       DMA_TO_DEVICE);
 140                                 desc_ptr++;
 141                                 if (++num_descriptors_this_page >= vsg->descriptors_per_page) {
 142                                         num_descriptors_this_page = 0;
 143                                         desc_ptr = vsg->desc_pages[++cur_descriptor_page];
 144                                 }
 145                         }
 146
 147                         num_desc++;
 148                         cur_mem += remaining_len;
 149                         cur_fb += remaining_len;
 150                 }
 151
 152                 mem_addr += xfer->mem_stride;
 153                 fb_addr += xfer->fb_stride;
 154         }
 155
 156         if (mode == 1) {
 157                 vsg->chain_start = next;
 158                 vsg->state = dr_via_device_mapped;
 159         }
 160         vsg->num_desc = num_desc;
 161 }
 162
 163 /*
 164  * Function that frees up all resources for a blit. It is usable even if the
 165  * blit info has only been partially built as long as the status enum is consistent
 166  * with the actual status of the used resources.
 167  */
 168
 169
 170 static void
 171 via_free_sg_info(struct pci_dev *pdev, drm_via_sg_info_t *vsg)
 172 {
 173         struct page *page;
 174         int i;
 175
 176         switch(vsg->state) {
 177         case dr_via_device_mapped:
 178                 via_unmap_blit_from_device(pdev, vsg);
 179         case dr_via_desc_pages_alloc:
 180                 for (i=0; i<vsg->num_desc_pages; ++i) {
 181                         if (vsg->desc_pages[i] != NULL)
 182                           free_page((unsigned long)vsg->desc_pages[i]);
 183                 }
 184                 kfree(vsg->desc_pages);
 185         case dr_via_pages_locked:
 186                 for (i=0; i<vsg->num_pages; ++i) {
 187                         if ( NULL != (page = vsg->pages[i])) {
 188                                 if (! PageReserved(page) && (DMA_FROM_DEVICE == vsg->direction))
 189                                         SetPageDirty(page);
 190                                 page_cache_release(page);
 191                         }
 192                 }
 193         case dr_via_pages_alloc:
 194                 vfree(vsg->pages);
 195         default:
 196                 vsg->state = dr_via_sg_init;
 197         }
 198         if (vsg->bounce_buffer) {
 199                 vfree(vsg->bounce_buffer);
 200                 vsg->bounce_buffer = NULL;
 201         }
 202         vsg->free_on_sequence = 0;
 203 }
 204
 205 /*
 206  * Fire a blit engine.
 207  */
 208
 209 static void
 210 via_fire_dmablit(struct drm_device *dev, drm_via_sg_info_t *vsg, int engine)
 211 {
 212         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 213
 214         VIA_WRITE(VIA_PCI_DMA_MAR0 + engine*0x10, 0);
 215         VIA_WRITE(VIA_PCI_DMA_DAR0 + engine*0x10, 0);
 216         VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_DD | VIA_DMA_CSR_TD |
 217                   VIA_DMA_CSR_DE);
 218         VIA_WRITE(VIA_PCI_DMA_MR0  + engine*0x04, VIA_DMA_MR_CM | VIA_DMA_MR_TDIE);
 219         VIA_WRITE(VIA_PCI_DMA_BCR0 + engine*0x10, 0);
 220         VIA_WRITE(VIA_PCI_DMA_DPR0 + engine*0x10, vsg->chain_start);
 221         DRM_WRITEMEMORYBARRIER();
 222         VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_DE | VIA_DMA_CSR_TS);
 223         VIA_READ(VIA_PCI_DMA_CSR0 + engine*0x04);
 224 }
 225
 226 /*
 227  * Obtain a page pointer array and lock all pages into system memory. A segmentation violation will
 228  * occur here if the calling user does not have access to the submitted address.
 229  */
 230
 231 static int
 232 via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
 233 {
 234         int ret;
 235         unsigned long first_pfn = VIA_PFN(xfer->mem_addr);
 236         vsg->num_pages = VIA_PFN(xfer->mem_addr + (xfer->num_lines * xfer->mem_stride -1)) -
 237                 first_pfn + 1;
 238
 239         if (NULL == (vsg->pages = vmalloc(sizeof(struct page *) * vsg->num_pages)))
 240                 return -ENOMEM;
 241         memset(vsg->pages, 0, sizeof(struct page *) * vsg->num_pages);
 242         down_read(&current->mm->mmap_sem);
 243         ret = get_user_pages(current, current->mm,
 244                              (unsigned long)xfer->mem_addr,
 245                              vsg->num_pages,
 246                              (vsg->direction == DMA_FROM_DEVICE),
 247                              0, vsg->pages, NULL);
 248
 249         up_read(&current->mm->mmap_sem);
 250         if (ret != vsg->num_pages) {
 251                 if (ret < 0)
 252                         return ret;
 253                 vsg->state = dr_via_pages_locked;
 254                 return -EINVAL;
 255         }
 256         vsg->state = dr_via_pages_locked;
 257         DRM_DEBUG("DMA pages locked\n");
 258         return 0;
 259 }
 260
 261 /*
 262  * Allocate DMA capable memory for the blit descriptor chain, and an array that keeps track of the
 263  * pages we allocate. We don't want to use kmalloc for the descriptor chain because it may be
 264  * quite large for some blits, and pages don't need to be contingous.
 265  */
 266
 267 static int
 268 via_alloc_desc_pages(drm_via_sg_info_t *vsg)
 269 {
 270         int i;
 271
 272         vsg->descriptors_per_page = PAGE_SIZE / sizeof( drm_via_descriptor_t);
 273         vsg->num_desc_pages = (vsg->num_desc + vsg->descriptors_per_page - 1) /
 274                 vsg->descriptors_per_page;
 275
 276         if (NULL ==  (vsg->desc_pages = kcalloc(vsg->num_desc_pages, sizeof(void *), GFP_KERNEL)))
 277                 return -ENOMEM;
 278
 279         vsg->state = dr_via_desc_pages_alloc;
 280         for (i=0; i<vsg->num_desc_pages; ++i) {
 281                 if (NULL == (vsg->desc_pages[i] =
 282                              (drm_via_descriptor_t *) __get_free_page(GFP_KERNEL)))
 283                         return -ENOMEM;
 284         }
 285         DRM_DEBUG("Allocated %d pages for %d descriptors.\n", vsg->num_desc_pages,
 286                   vsg->num_desc);
 287         return 0;
 288 }
 289
 290 static void
 291 via_abort_dmablit(struct drm_device *dev, int engine)
 292 {
 293         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 294
 295         VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_TA);
 296 }
 297
 298 static void
 299 via_dmablit_engine_off(struct drm_device *dev, int engine)
 300 {
 301         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 302
 303         VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_TD | VIA_DMA_CSR_DD);
 304 }
 305
 306
 307
 308 /*
 309  * The dmablit part of the IRQ handler. Trying to do only reasonably fast things here.
 310  * The rest, like unmapping and freeing memory for done blits is done in a separate workqueue
 311  * task. Basically the task of the interrupt handler is to submit a new blit to the engine, while
 312  * the workqueue task takes care of processing associated with the old blit.
 313  */
 314
 315 void
 316 via_dmablit_handler(struct drm_device *dev, int engine, int from_irq)
 317 {
 318         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 319         drm_via_blitq_t *blitq = dev_priv->blit_queues + engine;
 320         int cur;
 321         int done_transfer;
 322         unsigned long irqsave=0;
 323         uint32_t status = 0;
 324
 325         DRM_DEBUG("DMA blit handler called. engine = %d, from_irq = %d, blitq = 0x%lx\n",
 326                   engine, from_irq, (unsigned long) blitq);
 327
 328         if (from_irq) {
 329                 spin_lock(&blitq->blit_lock);
 330         } else {
 331                 spin_lock_irqsave(&blitq->blit_lock, irqsave);
 332         }
 333
 334         done_transfer = blitq->is_active &&
 335           (( status = VIA_READ(VIA_PCI_DMA_CSR0 + engine*0x04)) & VIA_DMA_CSR_TD);
 336         done_transfer = done_transfer || ( blitq->aborting && !(status & VIA_DMA_CSR_DE));
 337
 338         cur = blitq->cur;
 339         if (done_transfer) {
 340
 341                 blitq->blits[cur]->aborted = blitq->aborting;
 342                 blitq->done_blit_handle++;
 343                 DRM_WAKEUP(blitq->blit_queue + cur);
 344
 345                 cur++;
 346                 if (cur >= VIA_NUM_BLIT_SLOTS)
 347                         cur = 0;
 348                 blitq->cur = cur;
 349
 350                 /*
 351                  * Clear transfer done flag.
 352                  */
 353
 354                 VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04,  VIA_DMA_CSR_TD);
 355
 356                 blitq->is_active = 0;
 357                 blitq->aborting = 0;
 358                 schedule_work(&blitq->wq);
 359
 360         } else if (blitq->is_active && time_after_eq(jiffies, blitq->end)) {
 361
 362                 /*
 363                  * Abort transfer after one second.
 364                  */
 365
 366                 via_abort_dmablit(dev, engine);
 367                 blitq->aborting = 1;
 368                 blitq->end = jiffies + DRM_HZ;
 369         }
 370
 371         if (!blitq->is_active) {
 372                 if (blitq->num_outstanding) {
 373                         via_fire_dmablit(dev, blitq->blits[cur], engine);
 374                         blitq->is_active = 1;
 375                         blitq->cur = cur;
 376                         blitq->num_outstanding--;
 377                         blitq->end = jiffies + DRM_HZ;
 378                         if (!timer_pending(&blitq->poll_timer))
 379                                 mod_timer(&blitq->poll_timer, jiffies + 1);
 380                 } else {
 381                         if (timer_pending(&blitq->poll_timer)) {
 382                                 del_timer(&blitq->poll_timer);
 383                         }
 384                         via_dmablit_engine_off(dev, engine);
 385                 }
 386         }
 387
 388         if (from_irq) {
 389                 spin_unlock(&blitq->blit_lock);
 390         } else {
 391                 spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 392         }
 393 }
 394
 395
 396
 397 /*
 398  * Check whether this blit is still active, performing necessary locking.
 399  */
 400
 401 static int
 402 via_dmablit_active(drm_via_blitq_t *blitq, int engine, uint32_t handle, wait_queue_head_t **queue)
 403 {
 404         unsigned long irqsave;
 405         uint32_t slot;
 406         int active;
 407
 408         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 409
 410         /*
 411          * Allow for handle wraparounds.
 412          */
 413
 414         active = ((blitq->done_blit_handle - handle) > (1 << 23)) &&
 415                 ((blitq->cur_blit_handle - handle) <= (1 << 23));
 416
 417         if (queue && active) {
 418                 slot = handle - blitq->done_blit_handle + blitq->cur -1;
 419                 if (slot >= VIA_NUM_BLIT_SLOTS) {
 420                         slot -= VIA_NUM_BLIT_SLOTS;
 421                 }
 422                 *queue = blitq->blit_queue + slot;
 423         }
 424
 425         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 426
 427         return active;
 428 }
 429
 430 /*
 431  * Sync. Wait for at least three seconds for the blit to be performed.
 432  */
 433
 434 static int
 435 via_dmablit_sync(struct drm_device *dev, uint32_t handle, int engine)
 436 {
 437
 438         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 439         drm_via_blitq_t *blitq = dev_priv->blit_queues + engine;
 440         wait_queue_head_t *queue;
 441         int ret = 0;
 442
 443         if (via_dmablit_active(blitq, engine, handle, &queue)) {
 444                 DRM_WAIT_ON(ret, *queue, 3 * DRM_HZ,
 445                             !via_dmablit_active(blitq, engine, handle, NULL));
 446         }
 447         DRM_DEBUG("DMA blit sync handle 0x%x engine %d returned %d\n",
 448                   handle, engine, ret);
 449
 450         return ret;
 451 }
 452
 453
 454 /*
 455  * A timer that regularly polls the blit engine in cases where we don't have interrupts:
 456  * a) Broken hardware (typically those that don't have any video capture facility).
 457  * b) Blit abort. The hardware doesn't send an interrupt when a blit is aborted.
 458  * The timer and hardware IRQ's can and do work in parallel. If the hardware has
 459  * irqs, it will shorten the latency somewhat.
 460  */
 461
 462
 463
 464 static void
 465 via_dmablit_timer(unsigned long data)
 466 {
 467         drm_via_blitq_t *blitq = (drm_via_blitq_t *) data;
 468         struct drm_device *dev = blitq->dev;
 469         int engine = (int)
 470                 (blitq - ((drm_via_private_t *)dev->dev_private)->blit_queues);
 471
 472         DRM_DEBUG("Polling timer called for engine %d, jiffies %lu\n", engine,
 473                   (unsigned long) jiffies);
 474
 475         via_dmablit_handler(dev, engine, 0);
 476
 477         if (!timer_pending(&blitq->poll_timer)) {
 478                 mod_timer(&blitq->poll_timer, jiffies + 1);
 479
 480                /*
 481                 * Rerun handler to delete timer if engines are off, and
 482                 * to shorten abort latency. This is a little nasty.
 483                 */
 484
 485                via_dmablit_handler(dev, engine, 0);
 486
 487         }
 488 }
 489
 490
 491
 492
 493 /*
 494  * Workqueue task that frees data and mappings associated with a blit.
 495  * Also wakes up waiting processes. Each of these tasks handles one
 496  * blit engine only and may not be called on each interrupt.
 497  */
 498
 499
 500 static void
 501 via_dmablit_workqueue(struct work_struct *work)
 502 {
 503         drm_via_blitq_t *blitq = container_of(work, drm_via_blitq_t, wq);
 504         struct drm_device *dev = blitq->dev;
 505         unsigned long irqsave;
 506         drm_via_sg_info_t *cur_sg;
 507         int cur_released;
 508
 509
 510         DRM_DEBUG("Workqueue task called for blit engine %ld\n",(unsigned long)
 511                   (blitq - ((drm_via_private_t *)dev->dev_private)->blit_queues));
 512
 513         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 514
 515         while(blitq->serviced != blitq->cur) {
 516
 517                 cur_released = blitq->serviced++;
 518
 519                 DRM_DEBUG("Releasing blit slot %d\n", cur_released);
 520
 521                 if (blitq->serviced >= VIA_NUM_BLIT_SLOTS)
 522                         blitq->serviced = 0;
 523
 524                 cur_sg = blitq->blits[cur_released];
 525                 blitq->num_free++;
 526
 527                 spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 528
 529                 DRM_WAKEUP(&blitq->busy_queue);
 530
 531                 via_free_sg_info(dev->pdev, cur_sg);
 532                 kfree(cur_sg);
 533
 534                 spin_lock_irqsave(&blitq->blit_lock, irqsave);
 535         }
 536
 537         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 538 }
 539
 540
 541 /*
 542  * Init all blit engines. Currently we use two, but some hardware have 4.
 543  */
 544
 545
 546 void
 547 via_init_dmablit(struct drm_device *dev)
 548 {
 549         int i,j;
 550         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 551         drm_via_blitq_t *blitq;
 552
 553         pci_set_master(dev->pdev);
 554
 555         for (i=0; i< VIA_NUM_BLIT_ENGINES; ++i) {
 556                 blitq = dev_priv->blit_queues + i;
 557                 blitq->dev = dev;
 558                 blitq->cur_blit_handle = 0;
 559                 blitq->done_blit_handle = 0;
 560                 blitq->head = 0;
 561                 blitq->cur = 0;
 562                 blitq->serviced = 0;
 563                 blitq->num_free = VIA_NUM_BLIT_SLOTS - 1;
 564                 blitq->num_outstanding = 0;
 565                 blitq->is_active = 0;
 566                 blitq->aborting = 0;
 567                 spin_lock_init(&blitq->blit_lock);
 568                 for (j=0; j<VIA_NUM_BLIT_SLOTS; ++j) {
 569                         DRM_INIT_WAITQUEUE(blitq->blit_queue + j);
 570                 }
 571                 DRM_INIT_WAITQUEUE(&blitq->busy_queue);
 572                 INIT_WORK(&blitq->wq, via_dmablit_workqueue);
 573                 setup_timer(&blitq->poll_timer, via_dmablit_timer,
 574                                 (unsigned long)blitq);
 575         }
 576 }
 577
 578 /*
 579  * Build all info and do all mappings required for a blit.
 580  */
 581
 582
 583 static int
 584 via_build_sg_info(struct drm_device *dev, drm_via_sg_info_t *vsg, drm_via_dmablit_t *xfer)
 585 {
 586         int draw = xfer->to_fb;
 587         int ret = 0;
 588
 589         vsg->direction = (draw) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
 590         vsg->bounce_buffer = NULL;
 591
 592         vsg->state = dr_via_sg_init;
 593
 594         if (xfer->num_lines <= 0 || xfer->line_length <= 0) {
 595                 DRM_ERROR("Zero size bitblt.\n");
 596                 return -EINVAL;
 597         }
 598
 599         /*
 600          * Below check is a driver limitation, not a hardware one. We
 601          * don't want to lock unused pages, and don't want to incoporate the
 602          * extra logic of avoiding them. Make sure there are no.
 603          * (Not a big limitation anyway.)
 604          */
 605
 606         if ((xfer->mem_stride - xfer->line_length) > 2*PAGE_SIZE) {
 607                 DRM_ERROR("Too large system memory stride. Stride: %d, "
 608                           "Length: %d\n", xfer->mem_stride, xfer->line_length);
 609                 return -EINVAL;
 610         }
 611
 612         if ((xfer->mem_stride == xfer->line_length) &&
 613            (xfer->fb_stride == xfer->line_length)) {
 614                 xfer->mem_stride *= xfer->num_lines;
 615                 xfer->line_length = xfer->mem_stride;
 616                 xfer->fb_stride = xfer->mem_stride;
 617                 xfer->num_lines = 1;
 618         }
 619
 620         /*
 621          * Don't lock an arbitrary large number of pages, since that causes a
 622          * DOS security hole.
 623          */
 624
 625         if (xfer->num_lines > 2048 || (xfer->num_lines*xfer->mem_stride > (2048*2048*4))) {
 626                 DRM_ERROR("Too large PCI DMA bitblt.\n");
 627                 return -EINVAL;
 628         }
 629
 630         /*
 631          * we allow a negative fb stride to allow flipping of images in
 632          * transfer.
 633          */
 634
 635         if (xfer->mem_stride < xfer->line_length ||
 636                 abs(xfer->fb_stride) < xfer->line_length) {
 637                 DRM_ERROR("Invalid frame-buffer / memory stride.\n");
 638                 return -EINVAL;
 639         }
 640
 641         /*
 642          * A hardware bug seems to be worked around if system memory addresses start on
 643          * 16 byte boundaries. This seems a bit restrictive however. VIA is contacted
 644          * about this. Meanwhile, impose the following restrictions:
 645          */
 646
 647 #ifdef VIA_BUGFREE
 648         if ((((unsigned long)xfer->mem_addr & 3) != ((unsigned long)xfer->fb_addr & 3)) ||
 649             ((xfer->num_lines > 1) && ((xfer->mem_stride & 3) != (xfer->fb_stride & 3)))) {
 650                 DRM_ERROR("Invalid DRM bitblt alignment.\n");
 651                 return -EINVAL;
 652         }
 653 #else
 654         if ((((unsigned long)xfer->mem_addr & 15) ||
 655               ((unsigned long)xfer->fb_addr & 3)) ||
 656            ((xfer->num_lines > 1) &&
 657            ((xfer->mem_stride & 15) || (xfer->fb_stride & 3)))) {
 658                 DRM_ERROR("Invalid DRM bitblt alignment.\n");
 659                 return -EINVAL;
 660         }
 661 #endif
 662
 663         if (0 != (ret = via_lock_all_dma_pages(vsg, xfer))) {
 664                 DRM_ERROR("Could not lock DMA pages.\n");
 665                 via_free_sg_info(dev->pdev, vsg);
 666                 return ret;
 667         }
 668
 669         via_map_blit_for_device(dev->pdev, xfer, vsg, 0);
 670         if (0 != (ret = via_alloc_desc_pages(vsg))) {
 671                 DRM_ERROR("Could not allocate DMA descriptor pages.\n");
 672                 via_free_sg_info(dev->pdev, vsg);
 673                 return ret;
 674         }
 675         via_map_blit_for_device(dev->pdev, xfer, vsg, 1);
 676
 677         return 0;
 678 }
 679
 680
 681 /*
 682  * Reserve one free slot in the blit queue. Will wait for one second for one
 683  * to become available. Otherwise -EBUSY is returned.
 684  */
 685
 686 static int
 687 via_dmablit_grab_slot(drm_via_blitq_t *blitq, int engine)
 688 {
 689         int ret=0;
 690         unsigned long irqsave;
 691
 692         DRM_DEBUG("Num free is %d\n", blitq->num_free);
 693         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 694         while(blitq->num_free == 0) {
 695                 spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 696
 697                 DRM_WAIT_ON(ret, blitq->busy_queue, DRM_HZ, blitq->num_free > 0);
 698                 if (ret) {
 699                         return (-EINTR == ret) ? -EAGAIN : ret;
 700                 }
 701
 702                 spin_lock_irqsave(&blitq->blit_lock, irqsave);
 703         }
 704
 705         blitq->num_free--;
 706         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 707
 708         return 0;
 709 }
 710
 711 /*
 712  * Hand back a free slot if we changed our mind.
 713  */
 714
 715 static void
 716 via_dmablit_release_slot(drm_via_blitq_t *blitq)
 717 {
 718         unsigned long irqsave;
 719
 720         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 721         blitq->num_free++;
 722         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 723         DRM_WAKEUP( &blitq->busy_queue );
 724 }
 725
 726 /*
 727  * Grab a free slot. Build blit info and queue a blit.
 728  */
 729
 730
 731 static int
 732 via_dmablit(struct drm_device *dev, drm_via_dmablit_t *xfer)
 733 {
 734         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 735         drm_via_sg_info_t *vsg;
 736         drm_via_blitq_t *blitq;
 737         int ret;
 738         int engine;
 739         unsigned long irqsave;
 740
 741         if (dev_priv == NULL) {
 742                 DRM_ERROR("Called without initialization.\n");
 743                 return -EINVAL;
 744         }
 745
 746         engine = (xfer->to_fb) ? 0 : 1;
 747         blitq = dev_priv->blit_queues + engine;
 748         if (0 != (ret = via_dmablit_grab_slot(blitq, engine))) {
 749                 return ret;
 750         }
 751         if (NULL == (vsg = kmalloc(sizeof(*vsg), GFP_KERNEL))) {
 752                 via_dmablit_release_slot(blitq);
 753                 return -ENOMEM;
 754         }
 755         if (0 != (ret = via_build_sg_info(dev, vsg, xfer))) {
 756                 via_dmablit_release_slot(blitq);
 757                 kfree(vsg);
 758                 return ret;
 759         }
 760         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 761
 762         blitq->blits[blitq->head++] = vsg;
 763         if (blitq->head >= VIA_NUM_BLIT_SLOTS)
 764                 blitq->head = 0;
 765         blitq->num_outstanding++;
 766         xfer->sync.sync_handle = ++blitq->cur_blit_handle;
 767
 768         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 769         xfer->sync.engine = engine;
 770
 771         via_dmablit_handler(dev, engine, 0);
 772
 773         return 0;
 774 }
 775
 776 /*
 777  * Sync on a previously submitted blit. Note that the X server use signals extensively, and
 778  * that there is a very big probability that this IOCTL will be interrupted by a signal. In that
 779  * case it returns with -EAGAIN for the signal to be delivered.
 780  * The caller should then reissue the IOCTL. This is similar to what is being done for drmGetLock().
 781  */
 782
 783 int
 784 via_dma_blit_sync( struct drm_device *dev, void *data, struct drm_file *file_priv )
 785 {
 786         drm_via_blitsync_t *sync = data;
 787         int err;
 788
 789         if (sync->engine >= VIA_NUM_BLIT_ENGINES)
 790                 return -EINVAL;
 791
 792         err = via_dmablit_sync(dev, sync->sync_handle, sync->engine);
 793
 794         if (-EINTR == err)
 795                 err = -EAGAIN;
 796
 797         return err;
 798 }
 799
 800
 801 /*
 802  * Queue a blit and hand back a handle to be used for sync. This IOCTL may be interrupted by a signal
 803  * while waiting for a free slot in the blit queue. In that case it returns with -EAGAIN and should
 804  * be reissued. See the above IOCTL code.
 805  */
 806
 807 int
 808 via_dma_blit( struct drm_device *dev, void *data, struct drm_file *file_priv )
 809 {
 810         drm_via_dmablit_t *xfer = data;
 811         int err;
 812
 813         err = via_dmablit(dev, xfer);
 814
 815         return err;
 816 }