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(drm_device_t *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 DRM_ERR(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 DRM_ERR(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 = kmalloc(sizeof(void *) * vsg->num_desc_pages, GFP_KERNEL)))
 277                 return DRM_ERR(ENOMEM);
 278
 279         memset(vsg->desc_pages, 0, sizeof(void *) * vsg->num_desc_pages);
 280         vsg->state = dr_via_desc_pages_alloc;
 281         for (i=0; i<vsg->num_desc_pages; ++i) {
 282                 if (NULL == (vsg->desc_pages[i] =
 283                              (drm_via_descriptor_t *) __get_free_page(GFP_KERNEL)))
 284                         return DRM_ERR(ENOMEM);
 285         }
 286         DRM_DEBUG("Allocated %d pages for %d descriptors.\n", vsg->num_desc_pages,
 287                   vsg->num_desc);
 288         return 0;
 289 }
 290
 291 static void
 292 via_abort_dmablit(drm_device_t *dev, int engine)
 293 {
 294         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 295
 296         VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_TA);
 297 }
 298
 299 static void
 300 via_dmablit_engine_off(drm_device_t *dev, int engine)
 301 {
 302         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 303
 304         VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04, VIA_DMA_CSR_TD | VIA_DMA_CSR_DD);
 305 }
 306
 307
 308
 309 /*
 310  * The dmablit part of the IRQ handler. Trying to do only reasonably fast things here.
 311  * The rest, like unmapping and freeing memory for done blits is done in a separate workqueue
 312  * task. Basically the task of the interrupt handler is to submit a new blit to the engine, while
 313  * the workqueue task takes care of processing associated with the old blit.
 314  */
 315
 316 void
 317 via_dmablit_handler(drm_device_t *dev, int engine, int from_irq)
 318 {
 319         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 320         drm_via_blitq_t *blitq = dev_priv->blit_queues + engine;
 321         int cur;
 322         int done_transfer;
 323         unsigned long irqsave=0;
 324         uint32_t status = 0;
 325
 326         DRM_DEBUG("DMA blit handler called. engine = %d, from_irq = %d, blitq = 0x%lx\n",
 327                   engine, from_irq, (unsigned long) blitq);
 328
 329         if (from_irq) {
 330                 spin_lock(&blitq->blit_lock);
 331         } else {
 332                 spin_lock_irqsave(&blitq->blit_lock, irqsave);
 333         }
 334
 335         done_transfer = blitq->is_active &&
 336           (( status = VIA_READ(VIA_PCI_DMA_CSR0 + engine*0x04)) & VIA_DMA_CSR_TD);
 337         done_transfer = done_transfer || ( blitq->aborting && !(status & VIA_DMA_CSR_DE));
 338
 339         cur = blitq->cur;
 340         if (done_transfer) {
 341
 342                 blitq->blits[cur]->aborted = blitq->aborting;
 343                 blitq->done_blit_handle++;
 344                 DRM_WAKEUP(blitq->blit_queue + cur);
 345
 346                 cur++;
 347                 if (cur >= VIA_NUM_BLIT_SLOTS)
 348                         cur = 0;
 349                 blitq->cur = cur;
 350
 351                 /*
 352                  * Clear transfer done flag.
 353                  */
 354
 355                 VIA_WRITE(VIA_PCI_DMA_CSR0 + engine*0x04,  VIA_DMA_CSR_TD);
 356
 357                 blitq->is_active = 0;
 358                 blitq->aborting = 0;
 359                 schedule_work(&blitq->wq);
 360
 361         } else if (blitq->is_active && time_after_eq(jiffies, blitq->end)) {
 362
 363                 /*
 364                  * Abort transfer after one second.
 365                  */
 366
 367                 via_abort_dmablit(dev, engine);
 368                 blitq->aborting = 1;
 369                 blitq->end = jiffies + DRM_HZ;
 370         }
 371
 372         if (!blitq->is_active) {
 373                 if (blitq->num_outstanding) {
 374                         via_fire_dmablit(dev, blitq->blits[cur], engine);
 375                         blitq->is_active = 1;
 376                         blitq->cur = cur;
 377                         blitq->num_outstanding--;
 378                         blitq->end = jiffies + DRM_HZ;
 379                         if (!timer_pending(&blitq->poll_timer)) {
 380                                 blitq->poll_timer.expires = jiffies+1;
 381                                 add_timer(&blitq->poll_timer);
 382                         }
 383                 } else {
 384                         if (timer_pending(&blitq->poll_timer)) {
 385                                 del_timer(&blitq->poll_timer);
 386                         }
 387                         via_dmablit_engine_off(dev, engine);
 388                 }
 389         }
 390
 391         if (from_irq) {
 392                 spin_unlock(&blitq->blit_lock);
 393         } else {
 394                 spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 395         }
 396 }
 397
 398
 399
 400 /*
 401  * Check whether this blit is still active, performing necessary locking.
 402  */
 403
 404 static int
 405 via_dmablit_active(drm_via_blitq_t *blitq, int engine, uint32_t handle, wait_queue_head_t **queue)
 406 {
 407         unsigned long irqsave;
 408         uint32_t slot;
 409         int active;
 410
 411         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 412
 413         /*
 414          * Allow for handle wraparounds.
 415          */
 416
 417         active = ((blitq->done_blit_handle - handle) > (1 << 23)) &&
 418                 ((blitq->cur_blit_handle - handle) <= (1 << 23));
 419
 420         if (queue && active) {
 421                 slot = handle - blitq->done_blit_handle + blitq->cur -1;
 422                 if (slot >= VIA_NUM_BLIT_SLOTS) {
 423                         slot -= VIA_NUM_BLIT_SLOTS;
 424                 }
 425                 *queue = blitq->blit_queue + slot;
 426         }
 427
 428         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 429
 430         return active;
 431 }
 432
 433 /*
 434  * Sync. Wait for at least three seconds for the blit to be performed.
 435  */
 436
 437 static int
 438 via_dmablit_sync(drm_device_t *dev, uint32_t handle, int engine)
 439 {
 440
 441         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 442         drm_via_blitq_t *blitq = dev_priv->blit_queues + engine;
 443         wait_queue_head_t *queue;
 444         int ret = 0;
 445
 446         if (via_dmablit_active(blitq, engine, handle, &queue)) {
 447                 DRM_WAIT_ON(ret, *queue, 3 * DRM_HZ,
 448                             !via_dmablit_active(blitq, engine, handle, NULL));
 449         }
 450         DRM_DEBUG("DMA blit sync handle 0x%x engine %d returned %d\n",
 451                   handle, engine, ret);
 452
 453         return ret;
 454 }
 455
 456
 457 /*
 458  * A timer that regularly polls the blit engine in cases where we don't have interrupts:
 459  * a) Broken hardware (typically those that don't have any video capture facility).
 460  * b) Blit abort. The hardware doesn't send an interrupt when a blit is aborted.
 461  * The timer and hardware IRQ's can and do work in parallel. If the hardware has
 462  * irqs, it will shorten the latency somewhat.
 463  */
 464
 465
 466
 467 static void
 468 via_dmablit_timer(unsigned long data)
 469 {
 470         drm_via_blitq_t *blitq = (drm_via_blitq_t *) data;
 471         drm_device_t *dev = blitq->dev;
 472         int engine = (int)
 473                 (blitq - ((drm_via_private_t *)dev->dev_private)->blit_queues);
 474
 475         DRM_DEBUG("Polling timer called for engine %d, jiffies %lu\n", engine,
 476                   (unsigned long) jiffies);
 477
 478         via_dmablit_handler(dev, engine, 0);
 479
 480         if (!timer_pending(&blitq->poll_timer)) {
 481                 blitq->poll_timer.expires = jiffies+1;
 482                 add_timer(&blitq->poll_timer);
 483
 484                /*
 485                 * Rerun handler to delete timer if engines are off, and
 486                 * to shorten abort latency. This is a little nasty.
 487                 */
 488
 489                via_dmablit_handler(dev, engine, 0);
 490
 491         }
 492 }
 493
 494
 495
 496
 497 /*
 498  * Workqueue task that frees data and mappings associated with a blit.
 499  * Also wakes up waiting processes. Each of these tasks handles one
 500  * blit engine only and may not be called on each interrupt.
 501  */
 502
 503
 504 static void
 505 via_dmablit_workqueue(struct work_struct *work)
 506 {
 507         drm_via_blitq_t *blitq = container_of(work, drm_via_blitq_t, wq);
 508         drm_device_t *dev = blitq->dev;
 509         unsigned long irqsave;
 510         drm_via_sg_info_t *cur_sg;
 511         int cur_released;
 512
 513
 514         DRM_DEBUG("Workqueue task called for blit engine %ld\n",(unsigned long)
 515                   (blitq - ((drm_via_private_t *)dev->dev_private)->blit_queues));
 516
 517         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 518
 519         while(blitq->serviced != blitq->cur) {
 520
 521                 cur_released = blitq->serviced++;
 522
 523                 DRM_DEBUG("Releasing blit slot %d\n", cur_released);
 524
 525                 if (blitq->serviced >= VIA_NUM_BLIT_SLOTS)
 526                         blitq->serviced = 0;
 527
 528                 cur_sg = blitq->blits[cur_released];
 529                 blitq->num_free++;
 530
 531                 spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 532
 533                 DRM_WAKEUP(&blitq->busy_queue);
 534
 535                 via_free_sg_info(dev->pdev, cur_sg);
 536                 kfree(cur_sg);
 537
 538                 spin_lock_irqsave(&blitq->blit_lock, irqsave);
 539         }
 540
 541         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 542 }
 543
 544
 545 /*
 546  * Init all blit engines. Currently we use two, but some hardware have 4.
 547  */
 548
 549
 550 void
 551 via_init_dmablit(drm_device_t *dev)
 552 {
 553         int i,j;
 554         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 555         drm_via_blitq_t *blitq;
 556
 557         pci_set_master(dev->pdev);
 558
 559         for (i=0; i< VIA_NUM_BLIT_ENGINES; ++i) {
 560                 blitq = dev_priv->blit_queues + i;
 561                 blitq->dev = dev;
 562                 blitq->cur_blit_handle = 0;
 563                 blitq->done_blit_handle = 0;
 564                 blitq->head = 0;
 565                 blitq->cur = 0;
 566                 blitq->serviced = 0;
 567                 blitq->num_free = VIA_NUM_BLIT_SLOTS;
 568                 blitq->num_outstanding = 0;
 569                 blitq->is_active = 0;
 570                 blitq->aborting = 0;
 571                 spin_lock_init(&blitq->blit_lock);
 572                 for (j=0; j<VIA_NUM_BLIT_SLOTS; ++j) {
 573                         DRM_INIT_WAITQUEUE(blitq->blit_queue + j);
 574                 }
 575                 DRM_INIT_WAITQUEUE(&blitq->busy_queue);
 576                 INIT_WORK(&blitq->wq, via_dmablit_workqueue);
 577                 init_timer(&blitq->poll_timer);
 578                 blitq->poll_timer.function = &via_dmablit_timer;
 579                 blitq->poll_timer.data = (unsigned long) blitq;
 580         }
 581 }
 582
 583 /*
 584  * Build all info and do all mappings required for a blit.
 585  */
 586
 587
 588 static int
 589 via_build_sg_info(drm_device_t *dev, drm_via_sg_info_t *vsg, drm_via_dmablit_t *xfer)
 590 {
 591         int draw = xfer->to_fb;
 592         int ret = 0;
 593
 594         vsg->direction = (draw) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
 595         vsg->bounce_buffer = NULL;
 596
 597         vsg->state = dr_via_sg_init;
 598
 599         if (xfer->num_lines <= 0 || xfer->line_length <= 0) {
 600                 DRM_ERROR("Zero size bitblt.\n");
 601                 return DRM_ERR(EINVAL);
 602         }
 603
 604         /*
 605          * Below check is a driver limitation, not a hardware one. We
 606          * don't want to lock unused pages, and don't want to incoporate the
 607          * extra logic of avoiding them. Make sure there are no.
 608          * (Not a big limitation anyway.)
 609          */
 610
 611         if ((xfer->mem_stride - xfer->line_length) >= PAGE_SIZE) {
 612                 DRM_ERROR("Too large system memory stride. Stride: %d, "
 613                           "Length: %d\n", xfer->mem_stride, xfer->line_length);
 614                 return DRM_ERR(EINVAL);
 615         }
 616
 617         if ((xfer->mem_stride == xfer->line_length) &&
 618            (xfer->fb_stride == xfer->line_length)) {
 619                 xfer->mem_stride *= xfer->num_lines;
 620                 xfer->line_length = xfer->mem_stride;
 621                 xfer->fb_stride = xfer->mem_stride;
 622                 xfer->num_lines = 1;
 623         }
 624
 625         /*
 626          * Don't lock an arbitrary large number of pages, since that causes a
 627          * DOS security hole.
 628          */
 629
 630         if (xfer->num_lines > 2048 || (xfer->num_lines*xfer->mem_stride > (2048*2048*4))) {
 631                 DRM_ERROR("Too large PCI DMA bitblt.\n");
 632                 return DRM_ERR(EINVAL);
 633         }
 634
 635         /*
 636          * we allow a negative fb stride to allow flipping of images in
 637          * transfer.
 638          */
 639
 640         if (xfer->mem_stride < xfer->line_length ||
 641                 abs(xfer->fb_stride) < xfer->line_length) {
 642                 DRM_ERROR("Invalid frame-buffer / memory stride.\n");
 643                 return DRM_ERR(EINVAL);
 644         }
 645
 646         /*
 647          * A hardware bug seems to be worked around if system memory addresses start on
 648          * 16 byte boundaries. This seems a bit restrictive however. VIA is contacted
 649          * about this. Meanwhile, impose the following restrictions:
 650          */
 651
 652 #ifdef VIA_BUGFREE
 653         if ((((unsigned long)xfer->mem_addr & 3) != ((unsigned long)xfer->fb_addr & 3)) ||
 654             ((xfer->num_lines > 1) && ((xfer->mem_stride & 3) != (xfer->fb_stride & 3)))) {
 655                 DRM_ERROR("Invalid DRM bitblt alignment.\n");
 656                 return DRM_ERR(EINVAL);
 657         }
 658 #else
 659         if ((((unsigned long)xfer->mem_addr & 15) ||
 660               ((unsigned long)xfer->fb_addr & 3)) ||
 661            ((xfer->num_lines > 1) &&
 662            ((xfer->mem_stride & 15) || (xfer->fb_stride & 3)))) {
 663                 DRM_ERROR("Invalid DRM bitblt alignment.\n");
 664                 return DRM_ERR(EINVAL);
 665         }
 666 #endif
 667
 668         if (0 != (ret = via_lock_all_dma_pages(vsg, xfer))) {
 669                 DRM_ERROR("Could not lock DMA pages.\n");
 670                 via_free_sg_info(dev->pdev, vsg);
 671                 return ret;
 672         }
 673
 674         via_map_blit_for_device(dev->pdev, xfer, vsg, 0);
 675         if (0 != (ret = via_alloc_desc_pages(vsg))) {
 676                 DRM_ERROR("Could not allocate DMA descriptor pages.\n");
 677                 via_free_sg_info(dev->pdev, vsg);
 678                 return ret;
 679         }
 680         via_map_blit_for_device(dev->pdev, xfer, vsg, 1);
 681
 682         return 0;
 683 }
 684
 685
 686 /*
 687  * Reserve one free slot in the blit queue. Will wait for one second for one
 688  * to become available. Otherwise -EBUSY is returned.
 689  */
 690
 691 static int
 692 via_dmablit_grab_slot(drm_via_blitq_t *blitq, int engine)
 693 {
 694         int ret=0;
 695         unsigned long irqsave;
 696
 697         DRM_DEBUG("Num free is %d\n", blitq->num_free);
 698         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 699         while(blitq->num_free == 0) {
 700                 spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 701
 702                 DRM_WAIT_ON(ret, blitq->busy_queue, DRM_HZ, blitq->num_free > 0);
 703                 if (ret) {
 704                         return (DRM_ERR(EINTR) == ret) ? DRM_ERR(EAGAIN) : ret;
 705                 }
 706
 707                 spin_lock_irqsave(&blitq->blit_lock, irqsave);
 708         }
 709
 710         blitq->num_free--;
 711         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 712
 713         return 0;
 714 }
 715
 716 /*
 717  * Hand back a free slot if we changed our mind.
 718  */
 719
 720 static void
 721 via_dmablit_release_slot(drm_via_blitq_t *blitq)
 722 {
 723         unsigned long irqsave;
 724
 725         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 726         blitq->num_free++;
 727         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 728         DRM_WAKEUP( &blitq->busy_queue );
 729 }
 730
 731 /*
 732  * Grab a free slot. Build blit info and queue a blit.
 733  */
 734
 735
 736 static int
 737 via_dmablit(drm_device_t *dev, drm_via_dmablit_t *xfer)
 738 {
 739         drm_via_private_t *dev_priv = (drm_via_private_t *)dev->dev_private;
 740         drm_via_sg_info_t *vsg;
 741         drm_via_blitq_t *blitq;
 742         int ret;
 743         int engine;
 744         unsigned long irqsave;
 745
 746         if (dev_priv == NULL) {
 747                 DRM_ERROR("Called without initialization.\n");
 748                 return DRM_ERR(EINVAL);
 749         }
 750
 751         engine = (xfer->to_fb) ? 0 : 1;
 752         blitq = dev_priv->blit_queues + engine;
 753         if (0 != (ret = via_dmablit_grab_slot(blitq, engine))) {
 754                 return ret;
 755         }
 756         if (NULL == (vsg = kmalloc(sizeof(*vsg), GFP_KERNEL))) {
 757                 via_dmablit_release_slot(blitq);
 758                 return DRM_ERR(ENOMEM);
 759         }
 760         if (0 != (ret = via_build_sg_info(dev, vsg, xfer))) {
 761                 via_dmablit_release_slot(blitq);
 762                 kfree(vsg);
 763                 return ret;
 764         }
 765         spin_lock_irqsave(&blitq->blit_lock, irqsave);
 766
 767         blitq->blits[blitq->head++] = vsg;
 768         if (blitq->head >= VIA_NUM_BLIT_SLOTS)
 769                 blitq->head = 0;
 770         blitq->num_outstanding++;
 771         xfer->sync.sync_handle = ++blitq->cur_blit_handle;
 772
 773         spin_unlock_irqrestore(&blitq->blit_lock, irqsave);
 774         xfer->sync.engine = engine;
 775
 776         via_dmablit_handler(dev, engine, 0);
 777
 778         return 0;
 779 }
 780
 781 /*
 782  * Sync on a previously submitted blit. Note that the X server use signals extensively, and
 783  * that there is a very big probability that this IOCTL will be interrupted by a signal. In that
 784  * case it returns with -EAGAIN for the signal to be delivered.
 785  * The caller should then reissue the IOCTL. This is similar to what is being done for drmGetLock().
 786  */
 787
 788 int
 789 via_dma_blit_sync( DRM_IOCTL_ARGS )
 790 {
 791         drm_via_blitsync_t sync;
 792         int err;
 793         DRM_DEVICE;
 794
 795         DRM_COPY_FROM_USER_IOCTL(sync, (drm_via_blitsync_t *)data, sizeof(sync));
 796
 797         if (sync.engine >= VIA_NUM_BLIT_ENGINES)
 798                 return DRM_ERR(EINVAL);
 799
 800         err = via_dmablit_sync(dev, sync.sync_handle, sync.engine);
 801
 802         if (DRM_ERR(EINTR) == err)
 803                 err = DRM_ERR(EAGAIN);
 804
 805         return err;
 806 }
 807
 808
 809 /*
 810  * Queue a blit and hand back a handle to be used for sync. This IOCTL may be interrupted by a signal
 811  * while waiting for a free slot in the blit queue. In that case it returns with -EAGAIN and should
 812  * be reissued. See the above IOCTL code.
 813  */
 814
 815 int
 816 via_dma_blit( DRM_IOCTL_ARGS )
 817 {
 818         drm_via_dmablit_t xfer;
 819         int err;
 820         DRM_DEVICE;
 821
 822         DRM_COPY_FROM_USER_IOCTL(xfer, (drm_via_dmablit_t __user *)data, sizeof(xfer));
 823
 824         err = via_dmablit(dev, &xfer);
 825
 826         DRM_COPY_TO_USER_IOCTL((void __user *)data, xfer, sizeof(xfer));
 827
 828         return err;
 829 }