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 u16 trans_index; 250 251 spin_lock_bh(&trans_info->spinlock); 252 253 list_move_tail(&trans->links, &trans_info->committed); 254 255 trans = list_first_entry(&trans_info->committed, 256 struct gsi_trans, links); 257 258 spin_unlock_bh(&trans_info->spinlock); 259 260 /* This allocated transaction is now committed */ 261 trans_info->allocated_id++; 262 263 WARN_ON(trans_info->committed_id == trans_info->allocated_id); 264 trans_index = trans_info->committed_id % channel->tre_count; 265 WARN_ON(trans != &trans_info->trans[trans_index]); 266 } 267 268 /* Move transactions from the committed list to the pending list */ 269 static void gsi_trans_move_pending(struct gsi_trans *trans) 270 { 271 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 272 struct gsi_trans_info *trans_info = &channel->trans_info; 273 u16 trans_index = trans - &trans_info->trans[0]; 274 struct list_head list; 275 u16 delta; 276 277 spin_lock_bh(&trans_info->spinlock); 278 279 /* Move this transaction and all predecessors to the pending list */ 280 list_cut_position(&list, &trans_info->committed, &trans->links); 281 list_splice_tail(&list, &trans_info->pending); 282 283 trans = list_first_entry_or_null(&trans_info->committed, 284 struct gsi_trans, links); 285 286 spin_unlock_bh(&trans_info->spinlock); 287 288 /* These committed transactions are now pending */ 289 delta = trans_index - trans_info->committed_id + 1; 290 trans_info->committed_id += delta % channel->tre_count; 291 292 if (trans) { 293 trans_index = trans_info->committed_id % channel->tre_count; 294 WARN_ON(trans != &trans_info->trans[trans_index]); 295 } else { 296 WARN_ON(trans_info->committed_id != 297 trans_info->allocated_id); 298 } 299 } 300 301 /* Move a transaction and all of its predecessors from the pending list 302 * to the completed list. 303 */ 304 void gsi_trans_move_complete(struct gsi_trans *trans) 305 { 306 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 307 struct gsi_trans_info *trans_info = &channel->trans_info; 308 struct list_head list; 309 310 spin_lock_bh(&trans_info->spinlock); 311 312 /* Move this transaction and all predecessors to completed list */ 313 list_cut_position(&list, &trans_info->pending, &trans->links); 314 list_splice_tail(&list, &trans_info->complete); 315 316 spin_unlock_bh(&trans_info->spinlock); 317 } 318 319 /* Move a transaction from the completed list to the polled list */ 320 void gsi_trans_move_polled(struct gsi_trans *trans) 321 { 322 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 323 struct gsi_trans_info *trans_info = &channel->trans_info; 324 325 spin_lock_bh(&trans_info->spinlock); 326 327 list_move_tail(&trans->links, &trans_info->polled); 328 329 spin_unlock_bh(&trans_info->spinlock); 330 } 331 332 /* Reserve some number of TREs on a channel. Returns true if successful */ 333 static bool 334 gsi_trans_tre_reserve(struct gsi_trans_info *trans_info, u32 tre_count) 335 { 336 int avail = atomic_read(&trans_info->tre_avail); 337 int new; 338 339 do { 340 new = avail - (int)tre_count; 341 if (unlikely(new < 0)) 342 return false; 343 } while (!atomic_try_cmpxchg(&trans_info->tre_avail, &avail, new)); 344 345 return true; 346 } 347 348 /* Release previously-reserved TRE entries to a channel */ 349 static void 350 gsi_trans_tre_release(struct gsi_trans_info *trans_info, u32 tre_count) 351 { 352 atomic_add(tre_count, &trans_info->tre_avail); 353 } 354 355 /* Return true if no transactions are allocated, false otherwise */ 356 bool gsi_channel_trans_idle(struct gsi *gsi, u32 channel_id) 357 { 358 u32 tre_max = gsi_channel_tre_max(gsi, channel_id); 359 struct gsi_trans_info *trans_info; 360 361 trans_info = &gsi->channel[channel_id].trans_info; 362 363 return atomic_read(&trans_info->tre_avail) == tre_max; 364 } 365 366 /* Allocate a GSI transaction on a channel */ 367 struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id, 368 u32 tre_count, 369 enum dma_data_direction direction) 370 { 371 struct gsi_channel *channel = &gsi->channel[channel_id]; 372 struct gsi_trans_info *trans_info; 373 struct gsi_trans *trans; 374 u16 trans_index; 375 376 if (WARN_ON(tre_count > channel->trans_tre_max)) 377 return NULL; 378 379 trans_info = &channel->trans_info; 380 381 /* If we can't reserve the TREs for the transaction, we're done */ 382 if (!gsi_trans_tre_reserve(trans_info, tre_count)) 383 return NULL; 384 385 trans_index = trans_info->free_id % channel->tre_count; 386 trans = &trans_info->trans[trans_index]; 387 memset(trans, 0, sizeof(*trans)); 388 389 /* Initialize non-zero fields in the transaction */ 390 trans->gsi = gsi; 391 trans->channel_id = channel_id; 392 trans->rsvd_count = tre_count; 393 init_completion(&trans->completion); 394 395 /* Allocate the scatterlist */ 396 trans->sgl = gsi_trans_pool_alloc(&trans_info->sg_pool, tre_count); 397 sg_init_marker(trans->sgl, tre_count); 398 399 trans->direction = direction; 400 refcount_set(&trans->refcount, 1); 401 402 /* This free transaction will now be allocated */ 403 trans_info->free_id++; 404 405 spin_lock_bh(&trans_info->spinlock); 406 407 list_add_tail(&trans->links, &trans_info->alloc); 408 409 spin_unlock_bh(&trans_info->spinlock); 410 411 return trans; 412 } 413 414 /* Free a previously-allocated transaction */ 415 void gsi_trans_free(struct gsi_trans *trans) 416 { 417 refcount_t *refcount = &trans->refcount; 418 struct gsi_trans_info *trans_info; 419 bool last; 420 421 /* We must hold the lock to release the last reference */ 422 if (refcount_dec_not_one(refcount)) 423 return; 424 425 trans_info = &trans->gsi->channel[trans->channel_id].trans_info; 426 427 spin_lock_bh(&trans_info->spinlock); 428 429 /* Reference might have been added before we got the lock */ 430 last = refcount_dec_and_test(refcount); 431 if (last) 432 list_del(&trans->links); 433 434 spin_unlock_bh(&trans_info->spinlock); 435 436 if (!last) 437 return; 438 439 /* Unused transactions are allocated but never committed or pending */ 440 if (!trans->used_count) { 441 trans_info->allocated_id++; 442 trans_info->committed_id++; 443 } else { 444 ipa_gsi_trans_release(trans); 445 } 446 447 /* Releasing the reserved TREs implicitly frees the sgl[] and 448 * (if present) info[] arrays, plus the transaction itself. 449 */ 450 gsi_trans_tre_release(trans_info, trans->rsvd_count); 451 } 452 453 /* Add an immediate command to a transaction */ 454 void gsi_trans_cmd_add(struct gsi_trans *trans, void *buf, u32 size, 455 dma_addr_t addr, enum ipa_cmd_opcode opcode) 456 { 457 u32 which = trans->used_count++; 458 struct scatterlist *sg; 459 460 WARN_ON(which >= trans->rsvd_count); 461 462 /* Commands are quite different from data transfer requests. 463 * Their payloads come from a pool whose memory is allocated 464 * using dma_alloc_coherent(). We therefore do *not* map them 465 * for DMA (unlike what we do for pages and skbs). 466 * 467 * When a transaction completes, the SGL is normally unmapped. 468 * A command transaction has direction DMA_NONE, which tells 469 * gsi_trans_complete() to skip the unmapping step. 470 * 471 * The only things we use directly in a command scatter/gather 472 * entry are the DMA address and length. We still need the SG 473 * table flags to be maintained though, so assign a NULL page 474 * pointer for that purpose. 475 */ 476 sg = &trans->sgl[which]; 477 sg_assign_page(sg, NULL); 478 sg_dma_address(sg) = addr; 479 sg_dma_len(sg) = size; 480 481 trans->cmd_opcode[which] = opcode; 482 } 483 484 /* Add a page transfer to a transaction. It will fill the only TRE. */ 485 int gsi_trans_page_add(struct gsi_trans *trans, struct page *page, u32 size, 486 u32 offset) 487 { 488 struct scatterlist *sg = &trans->sgl[0]; 489 int ret; 490 491 if (WARN_ON(trans->rsvd_count != 1)) 492 return -EINVAL; 493 if (WARN_ON(trans->used_count)) 494 return -EINVAL; 495 496 sg_set_page(sg, page, size, offset); 497 ret = dma_map_sg(trans->gsi->dev, sg, 1, trans->direction); 498 if (!ret) 499 return -ENOMEM; 500 501 trans->used_count++; /* Transaction now owns the (DMA mapped) page */ 502 503 return 0; 504 } 505 506 /* Add an SKB transfer to a transaction. No other TREs will be used. */ 507 int gsi_trans_skb_add(struct gsi_trans *trans, struct sk_buff *skb) 508 { 509 struct scatterlist *sg = &trans->sgl[0]; 510 u32 used_count; 511 int ret; 512 513 if (WARN_ON(trans->rsvd_count != 1)) 514 return -EINVAL; 515 if (WARN_ON(trans->used_count)) 516 return -EINVAL; 517 518 /* skb->len will not be 0 (checked early) */ 519 ret = skb_to_sgvec(skb, sg, 0, skb->len); 520 if (ret < 0) 521 return ret; 522 used_count = ret; 523 524 ret = dma_map_sg(trans->gsi->dev, sg, used_count, trans->direction); 525 if (!ret) 526 return -ENOMEM; 527 528 /* Transaction now owns the (DMA mapped) skb */ 529 trans->used_count += used_count; 530 531 return 0; 532 } 533 534 /* Compute the length/opcode value to use for a TRE */ 535 static __le16 gsi_tre_len_opcode(enum ipa_cmd_opcode opcode, u32 len) 536 { 537 return opcode == IPA_CMD_NONE ? cpu_to_le16((u16)len) 538 : cpu_to_le16((u16)opcode); 539 } 540 541 /* Compute the flags value to use for a given TRE */ 542 static __le32 gsi_tre_flags(bool last_tre, bool bei, enum ipa_cmd_opcode opcode) 543 { 544 enum gsi_tre_type tre_type; 545 u32 tre_flags; 546 547 tre_type = opcode == IPA_CMD_NONE ? GSI_RE_XFER : GSI_RE_IMMD_CMD; 548 tre_flags = u32_encode_bits(tre_type, TRE_FLAGS_TYPE_FMASK); 549 550 /* Last TRE contains interrupt flags */ 551 if (last_tre) { 552 /* All transactions end in a transfer completion interrupt */ 553 tre_flags |= TRE_FLAGS_IEOT_FMASK; 554 /* Don't interrupt when outbound commands are acknowledged */ 555 if (bei) 556 tre_flags |= TRE_FLAGS_BEI_FMASK; 557 } else { /* All others indicate there's more to come */ 558 tre_flags |= TRE_FLAGS_CHAIN_FMASK; 559 } 560 561 return cpu_to_le32(tre_flags); 562 } 563 564 static void gsi_trans_tre_fill(struct gsi_tre *dest_tre, dma_addr_t addr, 565 u32 len, bool last_tre, bool bei, 566 enum ipa_cmd_opcode opcode) 567 { 568 struct gsi_tre tre; 569 570 tre.addr = cpu_to_le64(addr); 571 tre.len_opcode = gsi_tre_len_opcode(opcode, len); 572 tre.reserved = 0; 573 tre.flags = gsi_tre_flags(last_tre, bei, opcode); 574 575 /* ARM64 can write 16 bytes as a unit with a single instruction. 576 * Doing the assignment this way is an attempt to make that happen. 577 */ 578 *dest_tre = tre; 579 } 580 581 /** 582 * __gsi_trans_commit() - Common GSI transaction commit code 583 * @trans: Transaction to commit 584 * @ring_db: Whether to tell the hardware about these queued transfers 585 * 586 * Formats channel ring TRE entries based on the content of the scatterlist. 587 * Maps a transaction pointer to the last ring entry used for the transaction, 588 * so it can be recovered when it completes. Moves the transaction to the 589 * pending list. Finally, updates the channel ring pointer and optionally 590 * rings the doorbell. 591 */ 592 static void __gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 593 { 594 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 595 struct gsi_ring *tre_ring = &channel->tre_ring; 596 enum ipa_cmd_opcode opcode = IPA_CMD_NONE; 597 bool bei = channel->toward_ipa; 598 struct gsi_tre *dest_tre; 599 struct scatterlist *sg; 600 u32 byte_count = 0; 601 u8 *cmd_opcode; 602 u32 avail; 603 u32 i; 604 605 WARN_ON(!trans->used_count); 606 607 /* Consume the entries. If we cross the end of the ring while 608 * filling them we'll switch to the beginning to finish. 609 * If there is no info array we're doing a simple data 610 * transfer request, whose opcode is IPA_CMD_NONE. 611 */ 612 cmd_opcode = channel->command ? &trans->cmd_opcode[0] : NULL; 613 avail = tre_ring->count - tre_ring->index % tre_ring->count; 614 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 615 for_each_sg(trans->sgl, sg, trans->used_count, i) { 616 bool last_tre = i == trans->used_count - 1; 617 dma_addr_t addr = sg_dma_address(sg); 618 u32 len = sg_dma_len(sg); 619 620 byte_count += len; 621 if (!avail--) 622 dest_tre = gsi_ring_virt(tre_ring, 0); 623 if (cmd_opcode) 624 opcode = *cmd_opcode++; 625 626 gsi_trans_tre_fill(dest_tre, addr, len, last_tre, bei, opcode); 627 dest_tre++; 628 } 629 /* Associate the TRE with the transaction */ 630 gsi_trans_map(trans, tre_ring->index); 631 632 tre_ring->index += trans->used_count; 633 634 trans->len = byte_count; 635 if (channel->toward_ipa) 636 gsi_trans_tx_committed(trans); 637 638 gsi_trans_move_committed(trans); 639 640 /* Ring doorbell if requested, or if all TREs are allocated */ 641 if (ring_db || !atomic_read(&channel->trans_info.tre_avail)) { 642 /* Report what we're handing off to hardware for TX channels */ 643 if (channel->toward_ipa) 644 gsi_trans_tx_queued(trans); 645 gsi_trans_move_pending(trans); 646 gsi_channel_doorbell(channel); 647 } 648 } 649 650 /* Commit a GSI transaction */ 651 void gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 652 { 653 if (trans->used_count) 654 __gsi_trans_commit(trans, ring_db); 655 else 656 gsi_trans_free(trans); 657 } 658 659 /* Commit a GSI transaction and wait for it to complete */ 660 void gsi_trans_commit_wait(struct gsi_trans *trans) 661 { 662 if (!trans->used_count) 663 goto out_trans_free; 664 665 refcount_inc(&trans->refcount); 666 667 __gsi_trans_commit(trans, true); 668 669 wait_for_completion(&trans->completion); 670 671 out_trans_free: 672 gsi_trans_free(trans); 673 } 674 675 /* Process the completion of a transaction; called while polling */ 676 void gsi_trans_complete(struct gsi_trans *trans) 677 { 678 /* If the entire SGL was mapped when added, unmap it now */ 679 if (trans->direction != DMA_NONE) 680 dma_unmap_sg(trans->gsi->dev, trans->sgl, trans->used_count, 681 trans->direction); 682 683 ipa_gsi_trans_complete(trans); 684 685 complete(&trans->completion); 686 687 gsi_trans_free(trans); 688 } 689 690 /* Cancel a channel's pending transactions */ 691 void gsi_channel_trans_cancel_pending(struct gsi_channel *channel) 692 { 693 struct gsi_trans_info *trans_info = &channel->trans_info; 694 struct gsi_trans *trans; 695 bool cancelled; 696 697 /* channel->gsi->mutex is held by caller */ 698 spin_lock_bh(&trans_info->spinlock); 699 700 cancelled = !list_empty(&trans_info->pending); 701 list_for_each_entry(trans, &trans_info->pending, links) 702 trans->cancelled = true; 703 704 list_splice_tail_init(&trans_info->pending, &trans_info->complete); 705 706 spin_unlock_bh(&trans_info->spinlock); 707 708 /* Schedule NAPI polling to complete the cancelled transactions */ 709 if (cancelled) 710 napi_schedule(&channel->napi); 711 } 712 713 /* Issue a command to read a single byte from a channel */ 714 int gsi_trans_read_byte(struct gsi *gsi, u32 channel_id, dma_addr_t addr) 715 { 716 struct gsi_channel *channel = &gsi->channel[channel_id]; 717 struct gsi_ring *tre_ring = &channel->tre_ring; 718 struct gsi_trans_info *trans_info; 719 struct gsi_tre *dest_tre; 720 721 trans_info = &channel->trans_info; 722 723 /* First reserve the TRE, if possible */ 724 if (!gsi_trans_tre_reserve(trans_info, 1)) 725 return -EBUSY; 726 727 /* Now fill the reserved TRE and tell the hardware */ 728 729 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 730 gsi_trans_tre_fill(dest_tre, addr, 1, true, false, IPA_CMD_NONE); 731 732 tre_ring->index++; 733 gsi_channel_doorbell(channel); 734 735 return 0; 736 } 737 738 /* Mark a gsi_trans_read_byte() request done */ 739 void gsi_trans_read_byte_done(struct gsi *gsi, u32 channel_id) 740 { 741 struct gsi_channel *channel = &gsi->channel[channel_id]; 742 743 gsi_trans_tre_release(&channel->trans_info, 1); 744 } 745 746 /* Initialize a channel's GSI transaction info */ 747 int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id) 748 { 749 struct gsi_channel *channel = &gsi->channel[channel_id]; 750 u32 tre_count = channel->tre_count; 751 struct gsi_trans_info *trans_info; 752 u32 tre_max; 753 int ret; 754 755 /* Ensure the size of a channel element is what's expected */ 756 BUILD_BUG_ON(sizeof(struct gsi_tre) != GSI_RING_ELEMENT_SIZE); 757 758 trans_info = &channel->trans_info; 759 760 /* The tre_avail field is what ultimately limits the number of 761 * outstanding transactions and their resources. A transaction 762 * allocation succeeds only if the TREs available are sufficient 763 * for what the transaction might need. 764 */ 765 tre_max = gsi_channel_tre_max(channel->gsi, channel_id); 766 atomic_set(&trans_info->tre_avail, tre_max); 767 768 /* We can't use more TREs than the number available in the ring. 769 * This limits the number of transactions that can be outstanding. 770 * Worst case is one TRE per transaction (but we actually limit 771 * it to something a little less than that). By allocating a 772 * power-of-two number of transactions we can use an index 773 * modulo that number to determine the next one that's free. 774 * Transactions are allocated one at a time. 775 */ 776 trans_info->trans = kcalloc(tre_count, sizeof(*trans_info->trans), 777 GFP_KERNEL); 778 if (!trans_info->trans) 779 return -ENOMEM; 780 trans_info->free_id = 0; /* all modulo channel->tre_count */ 781 trans_info->allocated_id = 0; 782 trans_info->committed_id = 0; 783 784 /* A completion event contains a pointer to the TRE that caused 785 * the event (which will be the last one used by the transaction). 786 * Each entry in this map records the transaction associated 787 * with a corresponding completed TRE. 788 */ 789 trans_info->map = kcalloc(tre_count, sizeof(*trans_info->map), 790 GFP_KERNEL); 791 if (!trans_info->map) { 792 ret = -ENOMEM; 793 goto err_trans_free; 794 } 795 796 /* A transaction uses a scatterlist array to represent the data 797 * transfers implemented by the transaction. Each scatterlist 798 * element is used to fill a single TRE when the transaction is 799 * committed. So we need as many scatterlist elements as the 800 * maximum number of TREs that can be outstanding. 801 */ 802 ret = gsi_trans_pool_init(&trans_info->sg_pool, 803 sizeof(struct scatterlist), 804 tre_max, channel->trans_tre_max); 805 if (ret) 806 goto err_map_free; 807 808 spin_lock_init(&trans_info->spinlock); 809 INIT_LIST_HEAD(&trans_info->alloc); 810 INIT_LIST_HEAD(&trans_info->committed); 811 INIT_LIST_HEAD(&trans_info->pending); 812 INIT_LIST_HEAD(&trans_info->complete); 813 INIT_LIST_HEAD(&trans_info->polled); 814 815 return 0; 816 817 err_map_free: 818 kfree(trans_info->map); 819 err_trans_free: 820 kfree(trans_info->trans); 821 822 dev_err(gsi->dev, "error %d initializing channel %u transactions\n", 823 ret, channel_id); 824 825 return ret; 826 } 827 828 /* Inverse of gsi_channel_trans_init() */ 829 void gsi_channel_trans_exit(struct gsi_channel *channel) 830 { 831 struct gsi_trans_info *trans_info = &channel->trans_info; 832 833 gsi_trans_pool_exit(&trans_info->sg_pool); 834 kfree(trans_info->trans); 835 kfree(trans_info->map); 836 } 837