root/drivers/gpu/host1x/cdma.c

DEFINITIONS

1. host1x_pushbuffer_destroy
2. host1x_pushbuffer_init
3. host1x_pushbuffer_push
4. host1x_pushbuffer_pop
5. host1x_pushbuffer_space
6. host1x_cdma_wait_locked
7. host1x_cdma_wait_pushbuffer_space
8. cdma_start_timer_locked
9. stop_cdma_timer_locked
10. update_cdma_locked
11. host1x_cdma_update_sync_queue
12. host1x_cdma_init
13. host1x_cdma_deinit
14. host1x_cdma_begin
15. host1x_cdma_push
16. host1x_cdma_push_wide
17. host1x_cdma_end
18. host1x_cdma_update

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Tegra host1x Command DMA
   4  *
   5  * Copyright (c) 2010-2013, NVIDIA Corporation.
   6  */
   7 
   8 
   9 #include <asm/cacheflush.h>
  10 #include <linux/device.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/host1x.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/kernel.h>
  15 #include <linux/kfifo.h>
  16 #include <linux/slab.h>
  17 #include <trace/events/host1x.h>
  18 
  19 #include "cdma.h"
  20 #include "channel.h"
  21 #include "dev.h"
  22 #include "debug.h"
  23 #include "job.h"
  24 
  25 /*
  26  * push_buffer
  27  *
  28  * The push buffer is a circular array of words to be fetched by command DMA.
  29  * Note that it works slightly differently to the sync queue; fence == pos
  30  * means that the push buffer is full, not empty.
  31  */
  32 
  33 /*
  34  * Typically the commands written into the push buffer are a pair of words. We
  35  * use slots to represent each of these pairs and to simplify things. Note the
  36  * strange number of slots allocated here. 512 slots will fit exactly within a
  37  * single memory page. We also need one additional word at the end of the push
  38  * buffer for the RESTART opcode that will instruct the CDMA to jump back to
  39  * the beginning of the push buffer. With 512 slots, this means that we'll use
  40  * 2 memory pages and waste 4092 bytes of the second page that will never be
  41  * used.
  42  */
  43 #define HOST1X_PUSHBUFFER_SLOTS 511
  44 
  45 /*
  46  * Clean up push buffer resources
  47  */
  48 static void host1x_pushbuffer_destroy(struct push_buffer *pb)
  49 {
  50         struct host1x_cdma *cdma = pb_to_cdma(pb);
  51         struct host1x *host1x = cdma_to_host1x(cdma);
  52 
  53         if (!pb->mapped)
  54                 return;
  55 
  56         if (host1x->domain) {
  57                 iommu_unmap(host1x->domain, pb->dma, pb->alloc_size);
  58                 free_iova(&host1x->iova, iova_pfn(&host1x->iova, pb->dma));
  59         }
  60 
  61         dma_free_wc(host1x->dev, pb->alloc_size, pb->mapped, pb->phys);
  62 
  63         pb->mapped = NULL;
  64         pb->phys = 0;
  65 }
  66 
  67 /*
  68  * Init push buffer resources
  69  */
  70 static int host1x_pushbuffer_init(struct push_buffer *pb)
  71 {
  72         struct host1x_cdma *cdma = pb_to_cdma(pb);
  73         struct host1x *host1x = cdma_to_host1x(cdma);
  74         struct iova *alloc;
  75         u32 size;
  76         int err;
  77 
  78         pb->mapped = NULL;
  79         pb->phys = 0;
  80         pb->size = HOST1X_PUSHBUFFER_SLOTS * 8;
  81 
  82         size = pb->size + 4;
  83 
  84         /* initialize buffer pointers */
  85         pb->fence = pb->size - 8;
  86         pb->pos = 0;
  87 
  88         if (host1x->domain) {
  89                 unsigned long shift;
  90 
  91                 size = iova_align(&host1x->iova, size);
  92 
  93                 pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
  94                                           GFP_KERNEL);
  95                 if (!pb->mapped)
  96                         return -ENOMEM;
  97 
  98                 shift = iova_shift(&host1x->iova);
  99                 alloc = alloc_iova(&host1x->iova, size >> shift,
 100                                    host1x->iova_end >> shift, true);
 101                 if (!alloc) {
 102                         err = -ENOMEM;
 103                         goto iommu_free_mem;
 104                 }
 105 
 106                 pb->dma = iova_dma_addr(&host1x->iova, alloc);
 107                 err = iommu_map(host1x->domain, pb->dma, pb->phys, size,
 108                                 IOMMU_READ);
 109                 if (err)
 110                         goto iommu_free_iova;
 111         } else {
 112                 pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
 113                                           GFP_KERNEL);
 114                 if (!pb->mapped)
 115                         return -ENOMEM;
 116 
 117                 pb->dma = pb->phys;
 118         }
 119 
 120         pb->alloc_size = size;
 121 
 122         host1x_hw_pushbuffer_init(host1x, pb);
 123 
 124         return 0;
 125 
 126 iommu_free_iova:
 127         __free_iova(&host1x->iova, alloc);
 128 iommu_free_mem:
 129         dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
 130 
 131         return err;
 132 }
 133 
 134 /*
 135  * Push two words to the push buffer
 136  * Caller must ensure push buffer is not full
 137  */
 138 static void host1x_pushbuffer_push(struct push_buffer *pb, u32 op1, u32 op2)
 139 {
 140         u32 *p = (u32 *)((void *)pb->mapped + pb->pos);
 141 
 142         WARN_ON(pb->pos == pb->fence);
 143         *(p++) = op1;
 144         *(p++) = op2;
 145         pb->pos += 8;
 146 
 147         if (pb->pos >= pb->size)
 148                 pb->pos -= pb->size;
 149 }
 150 
 151 /*
 152  * Pop a number of two word slots from the push buffer
 153  * Caller must ensure push buffer is not empty
 154  */
 155 static void host1x_pushbuffer_pop(struct push_buffer *pb, unsigned int slots)
 156 {
 157         /* Advance the next write position */
 158         pb->fence += slots * 8;
 159 
 160         if (pb->fence >= pb->size)
 161                 pb->fence -= pb->size;
 162 }
 163 
 164 /*
 165  * Return the number of two word slots free in the push buffer
 166  */
 167 static u32 host1x_pushbuffer_space(struct push_buffer *pb)
 168 {
 169         unsigned int fence = pb->fence;
 170 
 171         if (pb->fence < pb->pos)
 172                 fence += pb->size;
 173 
 174         return (fence - pb->pos) / 8;
 175 }
 176 
 177 /*
 178  * Sleep (if necessary) until the requested event happens
 179  *   - CDMA_EVENT_SYNC_QUEUE_EMPTY : sync queue is completely empty.
 180  *     - Returns 1
 181  *   - CDMA_EVENT_PUSH_BUFFER_SPACE : there is space in the push buffer
 182  *     - Return the amount of space (> 0)
 183  * Must be called with the cdma lock held.
 184  */
 185 unsigned int host1x_cdma_wait_locked(struct host1x_cdma *cdma,
 186                                      enum cdma_event event)
 187 {
 188         for (;;) {
 189                 struct push_buffer *pb = &cdma->push_buffer;
 190                 unsigned int space;
 191 
 192                 switch (event) {
 193                 case CDMA_EVENT_SYNC_QUEUE_EMPTY:
 194                         space = list_empty(&cdma->sync_queue) ? 1 : 0;
 195                         break;
 196 
 197                 case CDMA_EVENT_PUSH_BUFFER_SPACE:
 198                         space = host1x_pushbuffer_space(pb);
 199                         break;
 200 
 201                 default:
 202                         WARN_ON(1);
 203                         return -EINVAL;
 204                 }
 205 
 206                 if (space)
 207                         return space;
 208 
 209                 trace_host1x_wait_cdma(dev_name(cdma_to_channel(cdma)->dev),
 210                                        event);
 211 
 212                 /* If somebody has managed to already start waiting, yield */
 213                 if (cdma->event != CDMA_EVENT_NONE) {
 214                         mutex_unlock(&cdma->lock);
 215                         schedule();
 216                         mutex_lock(&cdma->lock);
 217                         continue;
 218                 }
 219 
 220                 cdma->event = event;
 221 
 222                 mutex_unlock(&cdma->lock);
 223                 wait_for_completion(&cdma->complete);
 224                 mutex_lock(&cdma->lock);
 225         }
 226 
 227         return 0;
 228 }
 229 
 230 /*
 231  * Sleep (if necessary) until the push buffer has enough free space.
 232  *
 233  * Must be called with the cdma lock held.
 234  */
 235 int host1x_cdma_wait_pushbuffer_space(struct host1x *host1x,
 236                                       struct host1x_cdma *cdma,
 237                                       unsigned int needed)
 238 {
 239         while (true) {
 240                 struct push_buffer *pb = &cdma->push_buffer;
 241                 unsigned int space;
 242 
 243                 space = host1x_pushbuffer_space(pb);
 244                 if (space >= needed)
 245                         break;
 246 
 247                 trace_host1x_wait_cdma(dev_name(cdma_to_channel(cdma)->dev),
 248                                        CDMA_EVENT_PUSH_BUFFER_SPACE);
 249 
 250                 host1x_hw_cdma_flush(host1x, cdma);
 251 
 252                 /* If somebody has managed to already start waiting, yield */
 253                 if (cdma->event != CDMA_EVENT_NONE) {
 254                         mutex_unlock(&cdma->lock);
 255                         schedule();
 256                         mutex_lock(&cdma->lock);
 257                         continue;
 258                 }
 259 
 260                 cdma->event = CDMA_EVENT_PUSH_BUFFER_SPACE;
 261 
 262                 mutex_unlock(&cdma->lock);
 263                 wait_for_completion(&cdma->complete);
 264                 mutex_lock(&cdma->lock);
 265         }
 266 
 267         return 0;
 268 }
 269 /*
 270  * Start timer that tracks the time spent by the job.
 271  * Must be called with the cdma lock held.
 272  */
 273 static void cdma_start_timer_locked(struct host1x_cdma *cdma,
 274                                     struct host1x_job *job)
 275 {
 276         struct host1x *host = cdma_to_host1x(cdma);
 277 
 278         if (cdma->timeout.client) {
 279                 /* timer already started */
 280                 return;
 281         }
 282 
 283         cdma->timeout.client = job->client;
 284         cdma->timeout.syncpt = host1x_syncpt_get(host, job->syncpt_id);
 285         cdma->timeout.syncpt_val = job->syncpt_end;
 286         cdma->timeout.start_ktime = ktime_get();
 287 
 288         schedule_delayed_work(&cdma->timeout.wq,
 289                               msecs_to_jiffies(job->timeout));
 290 }
 291 
 292 /*
 293  * Stop timer when a buffer submission completes.
 294  * Must be called with the cdma lock held.
 295  */
 296 static void stop_cdma_timer_locked(struct host1x_cdma *cdma)
 297 {
 298         cancel_delayed_work(&cdma->timeout.wq);
 299         cdma->timeout.client = NULL;
 300 }
 301 
 302 /*
 303  * For all sync queue entries that have already finished according to the
 304  * current sync point registers:
 305  *  - unpin & unref their mems
 306  *  - pop their push buffer slots
 307  *  - remove them from the sync queue
 308  * This is normally called from the host code's worker thread, but can be
 309  * called manually if necessary.
 310  * Must be called with the cdma lock held.
 311  */
 312 static void update_cdma_locked(struct host1x_cdma *cdma)
 313 {
 314         bool signal = false;
 315         struct host1x *host1x = cdma_to_host1x(cdma);
 316         struct host1x_job *job, *n;
 317 
 318         /* If CDMA is stopped, queue is cleared and we can return */
 319         if (!cdma->running)
 320                 return;
 321 
 322         /*
 323          * Walk the sync queue, reading the sync point registers as necessary,
 324          * to consume as many sync queue entries as possible without blocking
 325          */
 326         list_for_each_entry_safe(job, n, &cdma->sync_queue, list) {
 327                 struct host1x_syncpt *sp =
 328                         host1x_syncpt_get(host1x, job->syncpt_id);
 329 
 330                 /* Check whether this syncpt has completed, and bail if not */
 331                 if (!host1x_syncpt_is_expired(sp, job->syncpt_end)) {
 332                         /* Start timer on next pending syncpt */
 333                         if (job->timeout)
 334                                 cdma_start_timer_locked(cdma, job);
 335 
 336                         break;
 337                 }
 338 
 339                 /* Cancel timeout, when a buffer completes */
 340                 if (cdma->timeout.client)
 341                         stop_cdma_timer_locked(cdma);
 342 
 343                 /* Unpin the memory */
 344                 host1x_job_unpin(job);
 345 
 346                 /* Pop push buffer slots */
 347                 if (job->num_slots) {
 348                         struct push_buffer *pb = &cdma->push_buffer;
 349 
 350                         host1x_pushbuffer_pop(pb, job->num_slots);
 351 
 352                         if (cdma->event == CDMA_EVENT_PUSH_BUFFER_SPACE)
 353                                 signal = true;
 354                 }
 355 
 356                 list_del(&job->list);
 357                 host1x_job_put(job);
 358         }
 359 
 360         if (cdma->event == CDMA_EVENT_SYNC_QUEUE_EMPTY &&
 361             list_empty(&cdma->sync_queue))
 362                 signal = true;
 363 
 364         if (signal) {
 365                 cdma->event = CDMA_EVENT_NONE;
 366                 complete(&cdma->complete);
 367         }
 368 }
 369 
 370 void host1x_cdma_update_sync_queue(struct host1x_cdma *cdma,
 371                                    struct device *dev)
 372 {
 373         struct host1x *host1x = cdma_to_host1x(cdma);
 374         u32 restart_addr, syncpt_incrs, syncpt_val;
 375         struct host1x_job *job, *next_job = NULL;
 376 
 377         syncpt_val = host1x_syncpt_load(cdma->timeout.syncpt);
 378 
 379         dev_dbg(dev, "%s: starting cleanup (thresh %d)\n",
 380                 __func__, syncpt_val);
 381 
 382         /*
 383          * Move the sync_queue read pointer to the first entry that hasn't
 384          * completed based on the current HW syncpt value. It's likely there
 385          * won't be any (i.e. we're still at the head), but covers the case
 386          * where a syncpt incr happens just prior/during the teardown.
 387          */
 388 
 389         dev_dbg(dev, "%s: skip completed buffers still in sync_queue\n",
 390                 __func__);
 391 
 392         list_for_each_entry(job, &cdma->sync_queue, list) {
 393                 if (syncpt_val < job->syncpt_end) {
 394 
 395                         if (!list_is_last(&job->list, &cdma->sync_queue))
 396                                 next_job = list_next_entry(job, list);
 397 
 398                         goto syncpt_incr;
 399                 }
 400 
 401                 host1x_job_dump(dev, job);
 402         }
 403 
 404         /* all jobs have been completed */
 405         job = NULL;
 406 
 407 syncpt_incr:
 408 
 409         /*
 410          * Increment with CPU the remaining syncpts of a partially executed job.
 411          *
 412          * CDMA will continue execution starting with the next job or will get
 413          * into idle state.
 414          */
 415         if (next_job)
 416                 restart_addr = next_job->first_get;
 417         else
 418                 restart_addr = cdma->last_pos;
 419 
 420         /* do CPU increments for the remaining syncpts */
 421         if (job) {
 422                 dev_dbg(dev, "%s: perform CPU incr on pending buffers\n",
 423                         __func__);
 424 
 425                 /* won't need a timeout when replayed */
 426                 job->timeout = 0;
 427 
 428                 syncpt_incrs = job->syncpt_end - syncpt_val;
 429                 dev_dbg(dev, "%s: CPU incr (%d)\n", __func__, syncpt_incrs);
 430 
 431                 host1x_job_dump(dev, job);
 432 
 433                 /* safe to use CPU to incr syncpts */
 434                 host1x_hw_cdma_timeout_cpu_incr(host1x, cdma, job->first_get,
 435                                                 syncpt_incrs, job->syncpt_end,
 436                                                 job->num_slots);
 437 
 438                 dev_dbg(dev, "%s: finished sync_queue modification\n",
 439                         __func__);
 440         }
 441 
 442         /* roll back DMAGET and start up channel again */
 443         host1x_hw_cdma_resume(host1x, cdma, restart_addr);
 444 }
 445 
 446 /*
 447  * Create a cdma
 448  */
 449 int host1x_cdma_init(struct host1x_cdma *cdma)
 450 {
 451         int err;
 452 
 453         mutex_init(&cdma->lock);
 454         init_completion(&cdma->complete);
 455 
 456         INIT_LIST_HEAD(&cdma->sync_queue);
 457 
 458         cdma->event = CDMA_EVENT_NONE;
 459         cdma->running = false;
 460         cdma->torndown = false;
 461 
 462         err = host1x_pushbuffer_init(&cdma->push_buffer);
 463         if (err)
 464                 return err;
 465 
 466         return 0;
 467 }
 468 
 469 /*
 470  * Destroy a cdma
 471  */
 472 int host1x_cdma_deinit(struct host1x_cdma *cdma)
 473 {
 474         struct push_buffer *pb = &cdma->push_buffer;
 475         struct host1x *host1x = cdma_to_host1x(cdma);
 476 
 477         if (cdma->running) {
 478                 pr_warn("%s: CDMA still running\n", __func__);
 479                 return -EBUSY;
 480         }
 481 
 482         host1x_pushbuffer_destroy(pb);
 483         host1x_hw_cdma_timeout_destroy(host1x, cdma);
 484 
 485         return 0;
 486 }
 487 
 488 /*
 489  * Begin a cdma submit
 490  */
 491 int host1x_cdma_begin(struct host1x_cdma *cdma, struct host1x_job *job)
 492 {
 493         struct host1x *host1x = cdma_to_host1x(cdma);
 494 
 495         mutex_lock(&cdma->lock);
 496 
 497         if (job->timeout) {
 498                 /* init state on first submit with timeout value */
 499                 if (!cdma->timeout.initialized) {
 500                         int err;
 501 
 502                         err = host1x_hw_cdma_timeout_init(host1x, cdma,
 503                                                           job->syncpt_id);
 504                         if (err) {
 505                                 mutex_unlock(&cdma->lock);
 506                                 return err;
 507                         }
 508                 }
 509         }
 510 
 511         if (!cdma->running)
 512                 host1x_hw_cdma_start(host1x, cdma);
 513 
 514         cdma->slots_free = 0;
 515         cdma->slots_used = 0;
 516         cdma->first_get = cdma->push_buffer.pos;
 517 
 518         trace_host1x_cdma_begin(dev_name(job->channel->dev));
 519         return 0;
 520 }
 521 
 522 /*
 523  * Push two words into a push buffer slot
 524  * Blocks as necessary if the push buffer is full.
 525  */
 526 void host1x_cdma_push(struct host1x_cdma *cdma, u32 op1, u32 op2)
 527 {
 528         struct host1x *host1x = cdma_to_host1x(cdma);
 529         struct push_buffer *pb = &cdma->push_buffer;
 530         u32 slots_free = cdma->slots_free;
 531 
 532         if (host1x_debug_trace_cmdbuf)
 533                 trace_host1x_cdma_push(dev_name(cdma_to_channel(cdma)->dev),
 534                                        op1, op2);
 535 
 536         if (slots_free == 0) {
 537                 host1x_hw_cdma_flush(host1x, cdma);
 538                 slots_free = host1x_cdma_wait_locked(cdma,
 539                                                 CDMA_EVENT_PUSH_BUFFER_SPACE);
 540         }
 541 
 542         cdma->slots_free = slots_free - 1;
 543         cdma->slots_used++;
 544         host1x_pushbuffer_push(pb, op1, op2);
 545 }
 546 
 547 /*
 548  * Push four words into two consecutive push buffer slots. Note that extra
 549  * care needs to be taken not to split the two slots across the end of the
 550  * push buffer. Otherwise the RESTART opcode at the end of the push buffer
 551  * that ensures processing will restart at the beginning will break up the
 552  * four words.
 553  *
 554  * Blocks as necessary if the push buffer is full.
 555  */
 556 void host1x_cdma_push_wide(struct host1x_cdma *cdma, u32 op1, u32 op2,
 557                            u32 op3, u32 op4)
 558 {
 559         struct host1x_channel *channel = cdma_to_channel(cdma);
 560         struct host1x *host1x = cdma_to_host1x(cdma);
 561         struct push_buffer *pb = &cdma->push_buffer;
 562         unsigned int needed = 2, extra = 0, i;
 563         unsigned int space = cdma->slots_free;
 564 
 565         if (host1x_debug_trace_cmdbuf)
 566                 trace_host1x_cdma_push_wide(dev_name(channel->dev), op1, op2,
 567                                             op3, op4);
 568 
 569         /* compute number of extra slots needed for padding */
 570         if (pb->pos + 16 > pb->size) {
 571                 extra = (pb->size - pb->pos) / 8;
 572                 needed += extra;
 573         }
 574 
 575         host1x_cdma_wait_pushbuffer_space(host1x, cdma, needed);
 576         space = host1x_pushbuffer_space(pb);
 577 
 578         cdma->slots_free = space - needed;
 579         cdma->slots_used += needed;
 580 
 581         /*
 582          * Note that we rely on the fact that this is only used to submit wide
 583          * gather opcodes, which consist of 3 words, and they are padded with
 584          * a NOP to avoid having to deal with fractional slots (a slot always
 585          * represents 2 words). The fourth opcode passed to this function will
 586          * therefore always be a NOP.
 587          *
 588          * This works around a slight ambiguity when it comes to opcodes. For
 589          * all current host1x incarnations the NOP opcode uses the exact same
 590          * encoding (0x20000000), so we could hard-code the value here, but a
 591          * new incarnation may change it and break that assumption.
 592          */
 593         for (i = 0; i < extra; i++)
 594                 host1x_pushbuffer_push(pb, op4, op4);
 595 
 596         host1x_pushbuffer_push(pb, op1, op2);
 597         host1x_pushbuffer_push(pb, op3, op4);
 598 }
 599 
 600 /*
 601  * End a cdma submit
 602  * Kick off DMA, add job to the sync queue, and a number of slots to be freed
 603  * from the pushbuffer. The handles for a submit must all be pinned at the same
 604  * time, but they can be unpinned in smaller chunks.
 605  */
 606 void host1x_cdma_end(struct host1x_cdma *cdma,
 607                      struct host1x_job *job)
 608 {
 609         struct host1x *host1x = cdma_to_host1x(cdma);
 610         bool idle = list_empty(&cdma->sync_queue);
 611 
 612         host1x_hw_cdma_flush(host1x, cdma);
 613 
 614         job->first_get = cdma->first_get;
 615         job->num_slots = cdma->slots_used;
 616         host1x_job_get(job);
 617         list_add_tail(&job->list, &cdma->sync_queue);
 618 
 619         /* start timer on idle -> active transitions */
 620         if (job->timeout && idle)
 621                 cdma_start_timer_locked(cdma, job);
 622 
 623         trace_host1x_cdma_end(dev_name(job->channel->dev));
 624         mutex_unlock(&cdma->lock);
 625 }
 626 
 627 /*
 628  * Update cdma state according to current sync point values
 629  */
 630 void host1x_cdma_update(struct host1x_cdma *cdma)
 631 {
 632         mutex_lock(&cdma->lock);
 633         update_cdma_locked(cdma);
 634         mutex_unlock(&cdma->lock);
 635 }