1 // SPDX-License-Identifier: GPL-2.0 2 3 /* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved. 4 * Copyright (C) 2019-2020 Linaro Ltd. 5 */ 6 7 #include <linux/types.h> 8 #include <linux/bits.h> 9 #include <linux/bitfield.h> 10 #include <linux/refcount.h> 11 #include <linux/scatterlist.h> 12 #include <linux/dma-direction.h> 13 14 #include "gsi.h" 15 #include "gsi_private.h" 16 #include "gsi_trans.h" 17 #include "ipa_gsi.h" 18 #include "ipa_data.h" 19 #include "ipa_cmd.h" 20 21 /** 22 * DOC: GSI Transactions 23 * 24 * A GSI transaction abstracts the behavior of a GSI channel by representing 25 * everything about a related group of IPA commands in a single structure. 26 * (A "command" in this sense is either a data transfer or an IPA immediate 27 * command.) Most details of interaction with the GSI hardware are managed 28 * by the GSI transaction core, allowing users to simply describe commands 29 * to be performed. When a transaction has completed a callback function 30 * (dependent on the type of endpoint associated with the channel) allows 31 * cleanup of resources associated with the transaction. 32 * 33 * To perform a command (or set of them), a user of the GSI transaction 34 * interface allocates a transaction, indicating the number of TREs required 35 * (one per command). If sufficient TREs are available, they are reserved 36 * for use in the transaction and the allocation succeeds. This way 37 * exhaustion of the available TREs in a channel ring is detected 38 * as early as possible. All resources required to complete a transaction 39 * are allocated at transaction allocation time. 40 * 41 * Commands performed as part of a transaction are represented in an array 42 * of Linux scatterlist structures. This array is allocated with the 43 * transaction, and its entries are initialized using standard scatterlist 44 * functions (such as sg_set_buf() or skb_to_sgvec()). 45 * 46 * Once a transaction's scatterlist structures have been initialized, the 47 * transaction is committed. The caller is responsible for mapping buffers 48 * for DMA if necessary, and this should be done *before* allocating 49 * the transaction. Between a successful allocation and commit of a 50 * transaction no errors should occur. 51 * 52 * Committing transfers ownership of the entire transaction to the GSI 53 * transaction core. The GSI transaction code formats the content of 54 * the scatterlist array into the channel ring buffer and informs the 55 * hardware that new TREs are available to process. 56 * 57 * The last TRE in each transaction is marked to interrupt the AP when the 58 * GSI hardware has completed it. Because transfers described by TREs are 59 * performed strictly in order, signaling the completion of just the last 60 * TRE in the transaction is sufficient to indicate the full transaction 61 * is complete. 62 * 63 * When a transaction is complete, ipa_gsi_trans_complete() is called by the 64 * GSI code into the IPA layer, allowing it to perform any final cleanup 65 * required before the transaction is freed. 66 */ 67 68 /* Hardware values representing a transfer element type */ 69 enum gsi_tre_type { 70 GSI_RE_XFER = 0x2, 71 GSI_RE_IMMD_CMD = 0x3, 72 }; 73 74 /* An entry in a channel ring */ 75 struct gsi_tre { 76 __le64 addr; /* DMA address */ 77 __le16 len_opcode; /* length in bytes or enum IPA_CMD_* */ 78 __le16 reserved; 79 __le32 flags; /* TRE_FLAGS_* */ 80 }; 81 82 /* gsi_tre->flags mask values (in CPU byte order) */ 83 #define TRE_FLAGS_CHAIN_FMASK GENMASK(0, 0) 84 #define TRE_FLAGS_IEOT_FMASK GENMASK(9, 9) 85 #define TRE_FLAGS_BEI_FMASK GENMASK(10, 10) 86 #define TRE_FLAGS_TYPE_FMASK GENMASK(23, 16) 87 88 int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, 89 u32 max_alloc) 90 { 91 void *virt; 92 93 if (!size) 94 return -EINVAL; 95 if (count < max_alloc) 96 return -EINVAL; 97 if (!max_alloc) 98 return -EINVAL; 99 100 /* By allocating a few extra entries in our pool (one less 101 * than the maximum number that will be requested in a 102 * single allocation), we can always satisfy requests without 103 * ever worrying about straddling the end of the pool array. 104 * If there aren't enough entries starting at the free index, 105 * we just allocate free entries from the beginning of the pool. 106 */ 107 virt = kcalloc(count + max_alloc - 1, size, GFP_KERNEL); 108 if (!virt) 109 return -ENOMEM; 110 111 pool->base = virt; 112 /* If the allocator gave us any extra memory, use it */ 113 pool->count = ksize(pool->base) / size; 114 pool->free = 0; 115 pool->max_alloc = max_alloc; 116 pool->size = size; 117 pool->addr = 0; /* Only used for DMA pools */ 118 119 return 0; 120 } 121 122 void gsi_trans_pool_exit(struct gsi_trans_pool *pool) 123 { 124 kfree(pool->base); 125 memset(pool, 0, sizeof(*pool)); 126 } 127 128 /* Allocate the requested number of (zeroed) entries from the pool */ 129 /* Home-grown DMA pool. This way we can preallocate and use the tre_count 130 * to guarantee allocations will succeed. Even though we specify max_alloc 131 * (and it can be more than one), we only allow allocation of a single 132 * element from a DMA pool. 133 */ 134 int gsi_trans_pool_init_dma(struct device *dev, struct gsi_trans_pool *pool, 135 size_t size, u32 count, u32 max_alloc) 136 { 137 size_t total_size; 138 dma_addr_t addr; 139 void *virt; 140 141 if (!size) 142 return -EINVAL; 143 if (count < max_alloc) 144 return -EINVAL; 145 if (!max_alloc) 146 return -EINVAL; 147 148 /* Don't let allocations cross a power-of-two boundary */ 149 size = __roundup_pow_of_two(size); 150 total_size = (count + max_alloc - 1) * size; 151 152 /* The allocator will give us a power-of-2 number of pages 153 * sufficient to satisfy our request. Round up our requested 154 * size to avoid any unused space in the allocation. This way 155 * gsi_trans_pool_exit_dma() can assume the total allocated 156 * size is exactly (count * size). 157 */ 158 total_size = get_order(total_size) << PAGE_SHIFT; 159 160 virt = dma_alloc_coherent(dev, total_size, &addr, GFP_KERNEL); 161 if (!virt) 162 return -ENOMEM; 163 164 pool->base = virt; 165 pool->count = total_size / size; 166 pool->free = 0; 167 pool->size = size; 168 pool->max_alloc = max_alloc; 169 pool->addr = addr; 170 171 return 0; 172 } 173 174 void gsi_trans_pool_exit_dma(struct device *dev, struct gsi_trans_pool *pool) 175 { 176 size_t total_size = pool->count * pool->size; 177 178 dma_free_coherent(dev, total_size, pool->base, pool->addr); 179 memset(pool, 0, sizeof(*pool)); 180 } 181 182 /* Return the byte offset of the next free entry in the pool */ 183 static u32 gsi_trans_pool_alloc_common(struct gsi_trans_pool *pool, u32 count) 184 { 185 u32 offset; 186 187 WARN_ON(!count); 188 WARN_ON(count > pool->max_alloc); 189 190 /* Allocate from beginning if wrap would occur */ 191 if (count > pool->count - pool->free) 192 pool->free = 0; 193 194 offset = pool->free * pool->size; 195 pool->free += count; 196 memset(pool->base + offset, 0, count * pool->size); 197 198 return offset; 199 } 200 201 /* Allocate a contiguous block of zeroed entries from a pool */ 202 void *gsi_trans_pool_alloc(struct gsi_trans_pool *pool, u32 count) 203 { 204 return pool->base + gsi_trans_pool_alloc_common(pool, count); 205 } 206 207 /* Allocate a single zeroed entry from a DMA pool */ 208 void *gsi_trans_pool_alloc_dma(struct gsi_trans_pool *pool, dma_addr_t *addr) 209 { 210 u32 offset = gsi_trans_pool_alloc_common(pool, 1); 211 212 *addr = pool->addr + offset; 213 214 return pool->base + offset; 215 } 216 217 /* Map a TRE ring entry index to the transaction it is associated with */ 218 static void gsi_trans_map(struct gsi_trans *trans, u32 index) 219 { 220 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 221 222 /* The completion event will indicate the last TRE used */ 223 index += trans->used_count - 1; 224 225 /* Note: index *must* be used modulo the ring count here */ 226 channel->trans_info.map[index % channel->tre_ring.count] = trans; 227 } 228 229 /* Return the transaction mapped to a given ring entry */ 230 struct gsi_trans * 231 gsi_channel_trans_mapped(struct gsi_channel *channel, u32 index) 232 { 233 /* Note: index *must* be used modulo the ring count here */ 234 return channel->trans_info.map[index % channel->tre_ring.count]; 235 } 236 237 /* Return the oldest completed transaction for a channel (or null) */ 238 struct gsi_trans *gsi_channel_trans_complete(struct gsi_channel *channel) 239 { 240 return list_first_entry_or_null(&channel->trans_info.complete, 241 struct gsi_trans, links); 242 } 243 244 /* Move a transaction from the allocated list to the committed list */ 245 static void gsi_trans_move_committed(struct gsi_trans *trans) 246 { 247 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 248 struct gsi_trans_info *trans_info = &channel->trans_info; 249 250 spin_lock_bh(&trans_info->spinlock); 251 252 list_move_tail(&trans->links, &trans_info->committed); 253 254 spin_unlock_bh(&trans_info->spinlock); 255 } 256 257 /* Move transactions from the committed list to the pending list */ 258 static void gsi_trans_move_pending(struct gsi_trans *trans) 259 { 260 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 261 struct gsi_trans_info *trans_info = &channel->trans_info; 262 struct list_head list; 263 264 spin_lock_bh(&trans_info->spinlock); 265 266 /* Move this transaction and all predecessors to the pending list */ 267 list_cut_position(&list, &trans_info->committed, &trans->links); 268 list_splice_tail(&list, &trans_info->pending); 269 270 spin_unlock_bh(&trans_info->spinlock); 271 } 272 273 /* Move a transaction and all of its predecessors from the pending list 274 * to the completed list. 275 */ 276 void gsi_trans_move_complete(struct gsi_trans *trans) 277 { 278 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 279 struct gsi_trans_info *trans_info = &channel->trans_info; 280 struct list_head list; 281 282 spin_lock_bh(&trans_info->spinlock); 283 284 /* Move this transaction and all predecessors to completed list */ 285 list_cut_position(&list, &trans_info->pending, &trans->links); 286 list_splice_tail(&list, &trans_info->complete); 287 288 spin_unlock_bh(&trans_info->spinlock); 289 } 290 291 /* Move a transaction from the completed list to the polled list */ 292 void gsi_trans_move_polled(struct gsi_trans *trans) 293 { 294 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 295 struct gsi_trans_info *trans_info = &channel->trans_info; 296 297 spin_lock_bh(&trans_info->spinlock); 298 299 list_move_tail(&trans->links, &trans_info->polled); 300 301 spin_unlock_bh(&trans_info->spinlock); 302 } 303 304 /* Reserve some number of TREs on a channel. Returns true if successful */ 305 static bool 306 gsi_trans_tre_reserve(struct gsi_trans_info *trans_info, u32 tre_count) 307 { 308 int avail = atomic_read(&trans_info->tre_avail); 309 int new; 310 311 do { 312 new = avail - (int)tre_count; 313 if (unlikely(new < 0)) 314 return false; 315 } while (!atomic_try_cmpxchg(&trans_info->tre_avail, &avail, new)); 316 317 return true; 318 } 319 320 /* Release previously-reserved TRE entries to a channel */ 321 static void 322 gsi_trans_tre_release(struct gsi_trans_info *trans_info, u32 tre_count) 323 { 324 atomic_add(tre_count, &trans_info->tre_avail); 325 } 326 327 /* Return true if no transactions are allocated, false otherwise */ 328 bool gsi_channel_trans_idle(struct gsi *gsi, u32 channel_id) 329 { 330 u32 tre_max = gsi_channel_tre_max(gsi, channel_id); 331 struct gsi_trans_info *trans_info; 332 333 trans_info = &gsi->channel[channel_id].trans_info; 334 335 return atomic_read(&trans_info->tre_avail) == tre_max; 336 } 337 338 /* Allocate a GSI transaction on a channel */ 339 struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id, 340 u32 tre_count, 341 enum dma_data_direction direction) 342 { 343 struct gsi_channel *channel = &gsi->channel[channel_id]; 344 struct gsi_trans_info *trans_info; 345 struct gsi_trans *trans; 346 347 if (WARN_ON(tre_count > channel->trans_tre_max)) 348 return NULL; 349 350 trans_info = &channel->trans_info; 351 352 /* We reserve the TREs now, but consume them at commit time. 353 * If there aren't enough available, we're done. 354 */ 355 if (!gsi_trans_tre_reserve(trans_info, tre_count)) 356 return NULL; 357 358 /* Allocate and initialize non-zero fields in the transaction */ 359 trans = gsi_trans_pool_alloc(&trans_info->pool, 1); 360 trans->gsi = gsi; 361 trans->channel_id = channel_id; 362 trans->rsvd_count = tre_count; 363 init_completion(&trans->completion); 364 365 /* Allocate the scatterlist and (if requested) info entries. */ 366 trans->sgl = gsi_trans_pool_alloc(&trans_info->sg_pool, tre_count); 367 sg_init_marker(trans->sgl, tre_count); 368 369 trans->direction = direction; 370 371 spin_lock_bh(&trans_info->spinlock); 372 373 list_add_tail(&trans->links, &trans_info->alloc); 374 375 spin_unlock_bh(&trans_info->spinlock); 376 377 refcount_set(&trans->refcount, 1); 378 379 return trans; 380 } 381 382 /* Free a previously-allocated transaction */ 383 void gsi_trans_free(struct gsi_trans *trans) 384 { 385 refcount_t *refcount = &trans->refcount; 386 struct gsi_trans_info *trans_info; 387 bool last; 388 389 /* We must hold the lock to release the last reference */ 390 if (refcount_dec_not_one(refcount)) 391 return; 392 393 trans_info = &trans->gsi->channel[trans->channel_id].trans_info; 394 395 spin_lock_bh(&trans_info->spinlock); 396 397 /* Reference might have been added before we got the lock */ 398 last = refcount_dec_and_test(refcount); 399 if (last) 400 list_del(&trans->links); 401 402 spin_unlock_bh(&trans_info->spinlock); 403 404 if (!last) 405 return; 406 407 ipa_gsi_trans_release(trans); 408 409 /* Releasing the reserved TREs implicitly frees the sgl[] and 410 * (if present) info[] arrays, plus the transaction itself. 411 */ 412 gsi_trans_tre_release(trans_info, trans->rsvd_count); 413 } 414 415 /* Add an immediate command to a transaction */ 416 void gsi_trans_cmd_add(struct gsi_trans *trans, void *buf, u32 size, 417 dma_addr_t addr, enum ipa_cmd_opcode opcode) 418 { 419 u32 which = trans->used_count++; 420 struct scatterlist *sg; 421 422 WARN_ON(which >= trans->rsvd_count); 423 424 /* Commands are quite different from data transfer requests. 425 * Their payloads come from a pool whose memory is allocated 426 * using dma_alloc_coherent(). We therefore do *not* map them 427 * for DMA (unlike what we do for pages and skbs). 428 * 429 * When a transaction completes, the SGL is normally unmapped. 430 * A command transaction has direction DMA_NONE, which tells 431 * gsi_trans_complete() to skip the unmapping step. 432 * 433 * The only things we use directly in a command scatter/gather 434 * entry are the DMA address and length. We still need the SG 435 * table flags to be maintained though, so assign a NULL page 436 * pointer for that purpose. 437 */ 438 sg = &trans->sgl[which]; 439 sg_assign_page(sg, NULL); 440 sg_dma_address(sg) = addr; 441 sg_dma_len(sg) = size; 442 443 trans->cmd_opcode[which] = opcode; 444 } 445 446 /* Add a page transfer to a transaction. It will fill the only TRE. */ 447 int gsi_trans_page_add(struct gsi_trans *trans, struct page *page, u32 size, 448 u32 offset) 449 { 450 struct scatterlist *sg = &trans->sgl[0]; 451 int ret; 452 453 if (WARN_ON(trans->rsvd_count != 1)) 454 return -EINVAL; 455 if (WARN_ON(trans->used_count)) 456 return -EINVAL; 457 458 sg_set_page(sg, page, size, offset); 459 ret = dma_map_sg(trans->gsi->dev, sg, 1, trans->direction); 460 if (!ret) 461 return -ENOMEM; 462 463 trans->used_count++; /* Transaction now owns the (DMA mapped) page */ 464 465 return 0; 466 } 467 468 /* Add an SKB transfer to a transaction. No other TREs will be used. */ 469 int gsi_trans_skb_add(struct gsi_trans *trans, struct sk_buff *skb) 470 { 471 struct scatterlist *sg = &trans->sgl[0]; 472 u32 used_count; 473 int ret; 474 475 if (WARN_ON(trans->rsvd_count != 1)) 476 return -EINVAL; 477 if (WARN_ON(trans->used_count)) 478 return -EINVAL; 479 480 /* skb->len will not be 0 (checked early) */ 481 ret = skb_to_sgvec(skb, sg, 0, skb->len); 482 if (ret < 0) 483 return ret; 484 used_count = ret; 485 486 ret = dma_map_sg(trans->gsi->dev, sg, used_count, trans->direction); 487 if (!ret) 488 return -ENOMEM; 489 490 /* Transaction now owns the (DMA mapped) skb */ 491 trans->used_count += used_count; 492 493 return 0; 494 } 495 496 /* Compute the length/opcode value to use for a TRE */ 497 static __le16 gsi_tre_len_opcode(enum ipa_cmd_opcode opcode, u32 len) 498 { 499 return opcode == IPA_CMD_NONE ? cpu_to_le16((u16)len) 500 : cpu_to_le16((u16)opcode); 501 } 502 503 /* Compute the flags value to use for a given TRE */ 504 static __le32 gsi_tre_flags(bool last_tre, bool bei, enum ipa_cmd_opcode opcode) 505 { 506 enum gsi_tre_type tre_type; 507 u32 tre_flags; 508 509 tre_type = opcode == IPA_CMD_NONE ? GSI_RE_XFER : GSI_RE_IMMD_CMD; 510 tre_flags = u32_encode_bits(tre_type, TRE_FLAGS_TYPE_FMASK); 511 512 /* Last TRE contains interrupt flags */ 513 if (last_tre) { 514 /* All transactions end in a transfer completion interrupt */ 515 tre_flags |= TRE_FLAGS_IEOT_FMASK; 516 /* Don't interrupt when outbound commands are acknowledged */ 517 if (bei) 518 tre_flags |= TRE_FLAGS_BEI_FMASK; 519 } else { /* All others indicate there's more to come */ 520 tre_flags |= TRE_FLAGS_CHAIN_FMASK; 521 } 522 523 return cpu_to_le32(tre_flags); 524 } 525 526 static void gsi_trans_tre_fill(struct gsi_tre *dest_tre, dma_addr_t addr, 527 u32 len, bool last_tre, bool bei, 528 enum ipa_cmd_opcode opcode) 529 { 530 struct gsi_tre tre; 531 532 tre.addr = cpu_to_le64(addr); 533 tre.len_opcode = gsi_tre_len_opcode(opcode, len); 534 tre.reserved = 0; 535 tre.flags = gsi_tre_flags(last_tre, bei, opcode); 536 537 /* ARM64 can write 16 bytes as a unit with a single instruction. 538 * Doing the assignment this way is an attempt to make that happen. 539 */ 540 *dest_tre = tre; 541 } 542 543 /** 544 * __gsi_trans_commit() - Common GSI transaction commit code 545 * @trans: Transaction to commit 546 * @ring_db: Whether to tell the hardware about these queued transfers 547 * 548 * Formats channel ring TRE entries based on the content of the scatterlist. 549 * Maps a transaction pointer to the last ring entry used for the transaction, 550 * so it can be recovered when it completes. Moves the transaction to the 551 * pending list. Finally, updates the channel ring pointer and optionally 552 * rings the doorbell. 553 */ 554 static void __gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 555 { 556 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 557 struct gsi_ring *tre_ring = &channel->tre_ring; 558 enum ipa_cmd_opcode opcode = IPA_CMD_NONE; 559 bool bei = channel->toward_ipa; 560 struct gsi_tre *dest_tre; 561 struct scatterlist *sg; 562 u32 byte_count = 0; 563 u8 *cmd_opcode; 564 u32 avail; 565 u32 i; 566 567 WARN_ON(!trans->used_count); 568 569 /* Consume the entries. If we cross the end of the ring while 570 * filling them we'll switch to the beginning to finish. 571 * If there is no info array we're doing a simple data 572 * transfer request, whose opcode is IPA_CMD_NONE. 573 */ 574 cmd_opcode = channel->command ? &trans->cmd_opcode[0] : NULL; 575 avail = tre_ring->count - tre_ring->index % tre_ring->count; 576 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 577 for_each_sg(trans->sgl, sg, trans->used_count, i) { 578 bool last_tre = i == trans->used_count - 1; 579 dma_addr_t addr = sg_dma_address(sg); 580 u32 len = sg_dma_len(sg); 581 582 byte_count += len; 583 if (!avail--) 584 dest_tre = gsi_ring_virt(tre_ring, 0); 585 if (cmd_opcode) 586 opcode = *cmd_opcode++; 587 588 gsi_trans_tre_fill(dest_tre, addr, len, last_tre, bei, opcode); 589 dest_tre++; 590 } 591 /* Associate the TRE with the transaction */ 592 gsi_trans_map(trans, tre_ring->index); 593 594 tre_ring->index += trans->used_count; 595 596 trans->len = byte_count; 597 if (channel->toward_ipa) 598 gsi_trans_tx_committed(trans); 599 600 gsi_trans_move_committed(trans); 601 602 /* Ring doorbell if requested, or if all TREs are allocated */ 603 if (ring_db || !atomic_read(&channel->trans_info.tre_avail)) { 604 /* Report what we're handing off to hardware for TX channels */ 605 if (channel->toward_ipa) 606 gsi_trans_tx_queued(trans); 607 gsi_trans_move_pending(trans); 608 gsi_channel_doorbell(channel); 609 } 610 } 611 612 /* Commit a GSI transaction */ 613 void gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 614 { 615 if (trans->used_count) 616 __gsi_trans_commit(trans, ring_db); 617 else 618 gsi_trans_free(trans); 619 } 620 621 /* Commit a GSI transaction and wait for it to complete */ 622 void gsi_trans_commit_wait(struct gsi_trans *trans) 623 { 624 if (!trans->used_count) 625 goto out_trans_free; 626 627 refcount_inc(&trans->refcount); 628 629 __gsi_trans_commit(trans, true); 630 631 wait_for_completion(&trans->completion); 632 633 out_trans_free: 634 gsi_trans_free(trans); 635 } 636 637 /* Process the completion of a transaction; called while polling */ 638 void gsi_trans_complete(struct gsi_trans *trans) 639 { 640 /* If the entire SGL was mapped when added, unmap it now */ 641 if (trans->direction != DMA_NONE) 642 dma_unmap_sg(trans->gsi->dev, trans->sgl, trans->used_count, 643 trans->direction); 644 645 ipa_gsi_trans_complete(trans); 646 647 complete(&trans->completion); 648 649 gsi_trans_free(trans); 650 } 651 652 /* Cancel a channel's pending transactions */ 653 void gsi_channel_trans_cancel_pending(struct gsi_channel *channel) 654 { 655 struct gsi_trans_info *trans_info = &channel->trans_info; 656 struct gsi_trans *trans; 657 bool cancelled; 658 659 /* channel->gsi->mutex is held by caller */ 660 spin_lock_bh(&trans_info->spinlock); 661 662 cancelled = !list_empty(&trans_info->pending); 663 list_for_each_entry(trans, &trans_info->pending, links) 664 trans->cancelled = true; 665 666 list_splice_tail_init(&trans_info->pending, &trans_info->complete); 667 668 spin_unlock_bh(&trans_info->spinlock); 669 670 /* Schedule NAPI polling to complete the cancelled transactions */ 671 if (cancelled) 672 napi_schedule(&channel->napi); 673 } 674 675 /* Issue a command to read a single byte from a channel */ 676 int gsi_trans_read_byte(struct gsi *gsi, u32 channel_id, dma_addr_t addr) 677 { 678 struct gsi_channel *channel = &gsi->channel[channel_id]; 679 struct gsi_ring *tre_ring = &channel->tre_ring; 680 struct gsi_trans_info *trans_info; 681 struct gsi_tre *dest_tre; 682 683 trans_info = &channel->trans_info; 684 685 /* First reserve the TRE, if possible */ 686 if (!gsi_trans_tre_reserve(trans_info, 1)) 687 return -EBUSY; 688 689 /* Now fill the reserved TRE and tell the hardware */ 690 691 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 692 gsi_trans_tre_fill(dest_tre, addr, 1, true, false, IPA_CMD_NONE); 693 694 tre_ring->index++; 695 gsi_channel_doorbell(channel); 696 697 return 0; 698 } 699 700 /* Mark a gsi_trans_read_byte() request done */ 701 void gsi_trans_read_byte_done(struct gsi *gsi, u32 channel_id) 702 { 703 struct gsi_channel *channel = &gsi->channel[channel_id]; 704 705 gsi_trans_tre_release(&channel->trans_info, 1); 706 } 707 708 /* Initialize a channel's GSI transaction info */ 709 int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id) 710 { 711 struct gsi_channel *channel = &gsi->channel[channel_id]; 712 struct gsi_trans_info *trans_info; 713 u32 tre_max; 714 int ret; 715 716 /* Ensure the size of a channel element is what's expected */ 717 BUILD_BUG_ON(sizeof(struct gsi_tre) != GSI_RING_ELEMENT_SIZE); 718 719 /* The map array is used to determine what transaction is associated 720 * with a TRE that the hardware reports has completed. We need one 721 * map entry per TRE. 722 */ 723 trans_info = &channel->trans_info; 724 trans_info->map = kcalloc(channel->tre_count, sizeof(*trans_info->map), 725 GFP_KERNEL); 726 if (!trans_info->map) 727 return -ENOMEM; 728 729 /* We can't use more TREs than there are available in the ring. 730 * This limits the number of transactions that can be outstanding. 731 * Worst case is one TRE per transaction (but we actually limit 732 * it to something a little less than that). We allocate resources 733 * for transactions (including transaction structures) based on 734 * this maximum number. 735 */ 736 tre_max = gsi_channel_tre_max(channel->gsi, channel_id); 737 738 /* Transactions are allocated one at a time. */ 739 ret = gsi_trans_pool_init(&trans_info->pool, sizeof(struct gsi_trans), 740 tre_max, 1); 741 if (ret) 742 goto err_kfree; 743 744 /* A transaction uses a scatterlist array to represent the data 745 * transfers implemented by the transaction. Each scatterlist 746 * element is used to fill a single TRE when the transaction is 747 * committed. So we need as many scatterlist elements as the 748 * maximum number of TREs that can be outstanding. 749 */ 750 ret = gsi_trans_pool_init(&trans_info->sg_pool, 751 sizeof(struct scatterlist), 752 tre_max, channel->trans_tre_max); 753 if (ret) 754 goto err_trans_pool_exit; 755 756 /* Finally, the tre_avail field is what ultimately limits the number 757 * of outstanding transactions and their resources. A transaction 758 * allocation succeeds only if the TREs available are sufficient for 759 * what the transaction might need. Transaction resource pools are 760 * sized based on the maximum number of outstanding TREs, so there 761 * will always be resources available if there are TREs available. 762 */ 763 atomic_set(&trans_info->tre_avail, tre_max); 764 765 spin_lock_init(&trans_info->spinlock); 766 INIT_LIST_HEAD(&trans_info->alloc); 767 INIT_LIST_HEAD(&trans_info->committed); 768 INIT_LIST_HEAD(&trans_info->pending); 769 INIT_LIST_HEAD(&trans_info->complete); 770 INIT_LIST_HEAD(&trans_info->polled); 771 772 return 0; 773 774 err_trans_pool_exit: 775 gsi_trans_pool_exit(&trans_info->pool); 776 err_kfree: 777 kfree(trans_info->map); 778 779 dev_err(gsi->dev, "error %d initializing channel %u transactions\n", 780 ret, channel_id); 781 782 return ret; 783 } 784 785 /* Inverse of gsi_channel_trans_init() */ 786 void gsi_channel_trans_exit(struct gsi_channel *channel) 787 { 788 struct gsi_trans_info *trans_info = &channel->trans_info; 789 790 gsi_trans_pool_exit(&trans_info->sg_pool); 791 gsi_trans_pool_exit(&trans_info->pool); 792 kfree(trans_info->map); 793 } 794