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 struct gsi_trans_info *trans_info = &channel->trans_info; 241 u16 trans_id = trans_info->completed_id; 242 243 if (trans_id == trans_info->pending_id) { 244 gsi_channel_update(channel); 245 if (trans_id == trans_info->pending_id) 246 return NULL; 247 } 248 249 return &trans_info->trans[trans_id %= channel->tre_count]; 250 } 251 252 /* Move a transaction from allocated to committed state */ 253 static void gsi_trans_move_committed(struct gsi_trans *trans) 254 { 255 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 256 struct gsi_trans_info *trans_info = &channel->trans_info; 257 258 /* This allocated transaction is now committed */ 259 trans_info->allocated_id++; 260 } 261 262 /* Move committed transactions to pending state */ 263 static void gsi_trans_move_pending(struct gsi_trans *trans) 264 { 265 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 266 struct gsi_trans_info *trans_info = &channel->trans_info; 267 u16 trans_index = trans - &trans_info->trans[0]; 268 u16 delta; 269 270 /* These committed transactions are now pending */ 271 delta = trans_index - trans_info->committed_id + 1; 272 trans_info->committed_id += delta % channel->tre_count; 273 } 274 275 /* Move pending transactions to completed state */ 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 u16 trans_index = trans - trans_info->trans; 281 u16 delta; 282 283 /* These pending transactions are now completed */ 284 delta = trans_index - trans_info->pending_id + 1; 285 delta %= channel->tre_count; 286 trans_info->pending_id += delta; 287 } 288 289 /* Move a transaction from completed to polled state */ 290 void gsi_trans_move_polled(struct gsi_trans *trans) 291 { 292 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 293 struct gsi_trans_info *trans_info = &channel->trans_info; 294 295 /* This completed transaction is now polled */ 296 trans_info->completed_id++; 297 } 298 299 /* Reserve some number of TREs on a channel. Returns true if successful */ 300 static bool 301 gsi_trans_tre_reserve(struct gsi_trans_info *trans_info, u32 tre_count) 302 { 303 int avail = atomic_read(&trans_info->tre_avail); 304 int new; 305 306 do { 307 new = avail - (int)tre_count; 308 if (unlikely(new < 0)) 309 return false; 310 } while (!atomic_try_cmpxchg(&trans_info->tre_avail, &avail, new)); 311 312 return true; 313 } 314 315 /* Release previously-reserved TRE entries to a channel */ 316 static void 317 gsi_trans_tre_release(struct gsi_trans_info *trans_info, u32 tre_count) 318 { 319 atomic_add(tre_count, &trans_info->tre_avail); 320 } 321 322 /* Return true if no transactions are allocated, false otherwise */ 323 bool gsi_channel_trans_idle(struct gsi *gsi, u32 channel_id) 324 { 325 u32 tre_max = gsi_channel_tre_max(gsi, channel_id); 326 struct gsi_trans_info *trans_info; 327 328 trans_info = &gsi->channel[channel_id].trans_info; 329 330 return atomic_read(&trans_info->tre_avail) == tre_max; 331 } 332 333 /* Allocate a GSI transaction on a channel */ 334 struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id, 335 u32 tre_count, 336 enum dma_data_direction direction) 337 { 338 struct gsi_channel *channel = &gsi->channel[channel_id]; 339 struct gsi_trans_info *trans_info; 340 struct gsi_trans *trans; 341 u16 trans_index; 342 343 if (WARN_ON(tre_count > channel->trans_tre_max)) 344 return NULL; 345 346 trans_info = &channel->trans_info; 347 348 /* If we can't reserve the TREs for the transaction, we're done */ 349 if (!gsi_trans_tre_reserve(trans_info, tre_count)) 350 return NULL; 351 352 trans_index = trans_info->free_id % channel->tre_count; 353 trans = &trans_info->trans[trans_index]; 354 memset(trans, 0, sizeof(*trans)); 355 356 /* Initialize non-zero fields in the transaction */ 357 trans->gsi = gsi; 358 trans->channel_id = channel_id; 359 trans->rsvd_count = tre_count; 360 init_completion(&trans->completion); 361 362 /* Allocate the scatterlist */ 363 trans->sgl = gsi_trans_pool_alloc(&trans_info->sg_pool, tre_count); 364 sg_init_marker(trans->sgl, tre_count); 365 366 trans->direction = direction; 367 refcount_set(&trans->refcount, 1); 368 369 /* This free transaction is now allocated */ 370 trans_info->free_id++; 371 372 return trans; 373 } 374 375 /* Free a previously-allocated transaction */ 376 void gsi_trans_free(struct gsi_trans *trans) 377 { 378 struct gsi_trans_info *trans_info; 379 380 if (!refcount_dec_and_test(&trans->refcount)) 381 return; 382 383 /* Unused transactions are allocated but never committed, pending, 384 * completed, or polled. 385 */ 386 trans_info = &trans->gsi->channel[trans->channel_id].trans_info; 387 if (!trans->used_count) { 388 trans_info->allocated_id++; 389 trans_info->committed_id++; 390 trans_info->pending_id++; 391 trans_info->completed_id++; 392 } else { 393 ipa_gsi_trans_release(trans); 394 } 395 396 /* This transaction is now free */ 397 trans_info->polled_id++; 398 399 /* Releasing the reserved TREs implicitly frees the sgl[] and 400 * (if present) info[] arrays, plus the transaction itself. 401 */ 402 gsi_trans_tre_release(trans_info, trans->rsvd_count); 403 } 404 405 /* Add an immediate command to a transaction */ 406 void gsi_trans_cmd_add(struct gsi_trans *trans, void *buf, u32 size, 407 dma_addr_t addr, enum ipa_cmd_opcode opcode) 408 { 409 u32 which = trans->used_count++; 410 struct scatterlist *sg; 411 412 WARN_ON(which >= trans->rsvd_count); 413 414 /* Commands are quite different from data transfer requests. 415 * Their payloads come from a pool whose memory is allocated 416 * using dma_alloc_coherent(). We therefore do *not* map them 417 * for DMA (unlike what we do for pages and skbs). 418 * 419 * When a transaction completes, the SGL is normally unmapped. 420 * A command transaction has direction DMA_NONE, which tells 421 * gsi_trans_complete() to skip the unmapping step. 422 * 423 * The only things we use directly in a command scatter/gather 424 * entry are the DMA address and length. We still need the SG 425 * table flags to be maintained though, so assign a NULL page 426 * pointer for that purpose. 427 */ 428 sg = &trans->sgl[which]; 429 sg_assign_page(sg, NULL); 430 sg_dma_address(sg) = addr; 431 sg_dma_len(sg) = size; 432 433 trans->cmd_opcode[which] = opcode; 434 } 435 436 /* Add a page transfer to a transaction. It will fill the only TRE. */ 437 int gsi_trans_page_add(struct gsi_trans *trans, struct page *page, u32 size, 438 u32 offset) 439 { 440 struct scatterlist *sg = &trans->sgl[0]; 441 int ret; 442 443 if (WARN_ON(trans->rsvd_count != 1)) 444 return -EINVAL; 445 if (WARN_ON(trans->used_count)) 446 return -EINVAL; 447 448 sg_set_page(sg, page, size, offset); 449 ret = dma_map_sg(trans->gsi->dev, sg, 1, trans->direction); 450 if (!ret) 451 return -ENOMEM; 452 453 trans->used_count++; /* Transaction now owns the (DMA mapped) page */ 454 455 return 0; 456 } 457 458 /* Add an SKB transfer to a transaction. No other TREs will be used. */ 459 int gsi_trans_skb_add(struct gsi_trans *trans, struct sk_buff *skb) 460 { 461 struct scatterlist *sg = &trans->sgl[0]; 462 u32 used_count; 463 int ret; 464 465 if (WARN_ON(trans->rsvd_count != 1)) 466 return -EINVAL; 467 if (WARN_ON(trans->used_count)) 468 return -EINVAL; 469 470 /* skb->len will not be 0 (checked early) */ 471 ret = skb_to_sgvec(skb, sg, 0, skb->len); 472 if (ret < 0) 473 return ret; 474 used_count = ret; 475 476 ret = dma_map_sg(trans->gsi->dev, sg, used_count, trans->direction); 477 if (!ret) 478 return -ENOMEM; 479 480 /* Transaction now owns the (DMA mapped) skb */ 481 trans->used_count += used_count; 482 483 return 0; 484 } 485 486 /* Compute the length/opcode value to use for a TRE */ 487 static __le16 gsi_tre_len_opcode(enum ipa_cmd_opcode opcode, u32 len) 488 { 489 return opcode == IPA_CMD_NONE ? cpu_to_le16((u16)len) 490 : cpu_to_le16((u16)opcode); 491 } 492 493 /* Compute the flags value to use for a given TRE */ 494 static __le32 gsi_tre_flags(bool last_tre, bool bei, enum ipa_cmd_opcode opcode) 495 { 496 enum gsi_tre_type tre_type; 497 u32 tre_flags; 498 499 tre_type = opcode == IPA_CMD_NONE ? GSI_RE_XFER : GSI_RE_IMMD_CMD; 500 tre_flags = u32_encode_bits(tre_type, TRE_FLAGS_TYPE_FMASK); 501 502 /* Last TRE contains interrupt flags */ 503 if (last_tre) { 504 /* All transactions end in a transfer completion interrupt */ 505 tre_flags |= TRE_FLAGS_IEOT_FMASK; 506 /* Don't interrupt when outbound commands are acknowledged */ 507 if (bei) 508 tre_flags |= TRE_FLAGS_BEI_FMASK; 509 } else { /* All others indicate there's more to come */ 510 tre_flags |= TRE_FLAGS_CHAIN_FMASK; 511 } 512 513 return cpu_to_le32(tre_flags); 514 } 515 516 static void gsi_trans_tre_fill(struct gsi_tre *dest_tre, dma_addr_t addr, 517 u32 len, bool last_tre, bool bei, 518 enum ipa_cmd_opcode opcode) 519 { 520 struct gsi_tre tre; 521 522 tre.addr = cpu_to_le64(addr); 523 tre.len_opcode = gsi_tre_len_opcode(opcode, len); 524 tre.reserved = 0; 525 tre.flags = gsi_tre_flags(last_tre, bei, opcode); 526 527 /* ARM64 can write 16 bytes as a unit with a single instruction. 528 * Doing the assignment this way is an attempt to make that happen. 529 */ 530 *dest_tre = tre; 531 } 532 533 /** 534 * __gsi_trans_commit() - Common GSI transaction commit code 535 * @trans: Transaction to commit 536 * @ring_db: Whether to tell the hardware about these queued transfers 537 * 538 * Formats channel ring TRE entries based on the content of the scatterlist. 539 * Maps a transaction pointer to the last ring entry used for the transaction, 540 * so it can be recovered when it completes. Moves the transaction to the 541 * pending list. Finally, updates the channel ring pointer and optionally 542 * rings the doorbell. 543 */ 544 static void __gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 545 { 546 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 547 struct gsi_ring *tre_ring = &channel->tre_ring; 548 enum ipa_cmd_opcode opcode = IPA_CMD_NONE; 549 bool bei = channel->toward_ipa; 550 struct gsi_tre *dest_tre; 551 struct scatterlist *sg; 552 u32 byte_count = 0; 553 u8 *cmd_opcode; 554 u32 avail; 555 u32 i; 556 557 WARN_ON(!trans->used_count); 558 559 /* Consume the entries. If we cross the end of the ring while 560 * filling them we'll switch to the beginning to finish. 561 * If there is no info array we're doing a simple data 562 * transfer request, whose opcode is IPA_CMD_NONE. 563 */ 564 cmd_opcode = channel->command ? &trans->cmd_opcode[0] : NULL; 565 avail = tre_ring->count - tre_ring->index % tre_ring->count; 566 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 567 for_each_sg(trans->sgl, sg, trans->used_count, i) { 568 bool last_tre = i == trans->used_count - 1; 569 dma_addr_t addr = sg_dma_address(sg); 570 u32 len = sg_dma_len(sg); 571 572 byte_count += len; 573 if (!avail--) 574 dest_tre = gsi_ring_virt(tre_ring, 0); 575 if (cmd_opcode) 576 opcode = *cmd_opcode++; 577 578 gsi_trans_tre_fill(dest_tre, addr, len, last_tre, bei, opcode); 579 dest_tre++; 580 } 581 /* Associate the TRE with the transaction */ 582 gsi_trans_map(trans, tre_ring->index); 583 584 tre_ring->index += trans->used_count; 585 586 trans->len = byte_count; 587 if (channel->toward_ipa) 588 gsi_trans_tx_committed(trans); 589 590 gsi_trans_move_committed(trans); 591 592 /* Ring doorbell if requested, or if all TREs are allocated */ 593 if (ring_db || !atomic_read(&channel->trans_info.tre_avail)) { 594 /* Report what we're handing off to hardware for TX channels */ 595 if (channel->toward_ipa) 596 gsi_trans_tx_queued(trans); 597 gsi_trans_move_pending(trans); 598 gsi_channel_doorbell(channel); 599 } 600 } 601 602 /* Commit a GSI transaction */ 603 void gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 604 { 605 if (trans->used_count) 606 __gsi_trans_commit(trans, ring_db); 607 else 608 gsi_trans_free(trans); 609 } 610 611 /* Commit a GSI transaction and wait for it to complete */ 612 void gsi_trans_commit_wait(struct gsi_trans *trans) 613 { 614 if (!trans->used_count) 615 goto out_trans_free; 616 617 refcount_inc(&trans->refcount); 618 619 __gsi_trans_commit(trans, true); 620 621 wait_for_completion(&trans->completion); 622 623 out_trans_free: 624 gsi_trans_free(trans); 625 } 626 627 /* Process the completion of a transaction; called while polling */ 628 void gsi_trans_complete(struct gsi_trans *trans) 629 { 630 /* If the entire SGL was mapped when added, unmap it now */ 631 if (trans->direction != DMA_NONE) 632 dma_unmap_sg(trans->gsi->dev, trans->sgl, trans->used_count, 633 trans->direction); 634 635 ipa_gsi_trans_complete(trans); 636 637 complete(&trans->completion); 638 639 gsi_trans_free(trans); 640 } 641 642 /* Cancel a channel's pending transactions */ 643 void gsi_channel_trans_cancel_pending(struct gsi_channel *channel) 644 { 645 struct gsi_trans_info *trans_info = &channel->trans_info; 646 u16 trans_id = trans_info->pending_id; 647 648 /* channel->gsi->mutex is held by caller */ 649 650 /* If there are no pending transactions, we're done */ 651 if (trans_id == trans_info->committed_id) 652 return; 653 654 /* Mark all pending transactions cancelled */ 655 do { 656 struct gsi_trans *trans; 657 658 trans = &trans_info->trans[trans_id % channel->tre_count]; 659 trans->cancelled = true; 660 } while (++trans_id != trans_info->committed_id); 661 662 /* All pending transactions are now completed */ 663 trans_info->pending_id = trans_info->committed_id; 664 665 /* Schedule NAPI polling to complete the cancelled transactions */ 666 napi_schedule(&channel->napi); 667 } 668 669 /* Issue a command to read a single byte from a channel */ 670 int gsi_trans_read_byte(struct gsi *gsi, u32 channel_id, dma_addr_t addr) 671 { 672 struct gsi_channel *channel = &gsi->channel[channel_id]; 673 struct gsi_ring *tre_ring = &channel->tre_ring; 674 struct gsi_trans_info *trans_info; 675 struct gsi_tre *dest_tre; 676 677 trans_info = &channel->trans_info; 678 679 /* First reserve the TRE, if possible */ 680 if (!gsi_trans_tre_reserve(trans_info, 1)) 681 return -EBUSY; 682 683 /* Now fill the reserved TRE and tell the hardware */ 684 685 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 686 gsi_trans_tre_fill(dest_tre, addr, 1, true, false, IPA_CMD_NONE); 687 688 tre_ring->index++; 689 gsi_channel_doorbell(channel); 690 691 return 0; 692 } 693 694 /* Mark a gsi_trans_read_byte() request done */ 695 void gsi_trans_read_byte_done(struct gsi *gsi, u32 channel_id) 696 { 697 struct gsi_channel *channel = &gsi->channel[channel_id]; 698 699 gsi_trans_tre_release(&channel->trans_info, 1); 700 } 701 702 /* Initialize a channel's GSI transaction info */ 703 int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id) 704 { 705 struct gsi_channel *channel = &gsi->channel[channel_id]; 706 u32 tre_count = channel->tre_count; 707 struct gsi_trans_info *trans_info; 708 u32 tre_max; 709 int ret; 710 711 /* Ensure the size of a channel element is what's expected */ 712 BUILD_BUG_ON(sizeof(struct gsi_tre) != GSI_RING_ELEMENT_SIZE); 713 714 trans_info = &channel->trans_info; 715 716 /* The tre_avail field is what ultimately limits the number of 717 * outstanding transactions and their resources. A transaction 718 * allocation succeeds only if the TREs available are sufficient 719 * for what the transaction might need. 720 */ 721 tre_max = gsi_channel_tre_max(channel->gsi, channel_id); 722 atomic_set(&trans_info->tre_avail, tre_max); 723 724 /* We can't use more TREs than the number available in the ring. 725 * This limits the number of transactions that can be outstanding. 726 * Worst case is one TRE per transaction (but we actually limit 727 * it to something a little less than that). By allocating a 728 * power-of-two number of transactions we can use an index 729 * modulo that number to determine the next one that's free. 730 * Transactions are allocated one at a time. 731 */ 732 trans_info->trans = kcalloc(tre_count, sizeof(*trans_info->trans), 733 GFP_KERNEL); 734 if (!trans_info->trans) 735 return -ENOMEM; 736 trans_info->free_id = 0; /* all modulo channel->tre_count */ 737 trans_info->allocated_id = 0; 738 trans_info->committed_id = 0; 739 trans_info->pending_id = 0; 740 trans_info->completed_id = 0; 741 trans_info->polled_id = 0; 742 743 /* A completion event contains a pointer to the TRE that caused 744 * the event (which will be the last one used by the transaction). 745 * Each entry in this map records the transaction associated 746 * with a corresponding completed TRE. 747 */ 748 trans_info->map = kcalloc(tre_count, sizeof(*trans_info->map), 749 GFP_KERNEL); 750 if (!trans_info->map) { 751 ret = -ENOMEM; 752 goto err_trans_free; 753 } 754 755 /* A transaction uses a scatterlist array to represent the data 756 * transfers implemented by the transaction. Each scatterlist 757 * element is used to fill a single TRE when the transaction is 758 * committed. So we need as many scatterlist elements as the 759 * maximum number of TREs that can be outstanding. 760 */ 761 ret = gsi_trans_pool_init(&trans_info->sg_pool, 762 sizeof(struct scatterlist), 763 tre_max, channel->trans_tre_max); 764 if (ret) 765 goto err_map_free; 766 767 768 return 0; 769 770 err_map_free: 771 kfree(trans_info->map); 772 err_trans_free: 773 kfree(trans_info->trans); 774 775 dev_err(gsi->dev, "error %d initializing channel %u transactions\n", 776 ret, channel_id); 777 778 return ret; 779 } 780 781 /* Inverse of gsi_channel_trans_init() */ 782 void gsi_channel_trans_exit(struct gsi_channel *channel) 783 { 784 struct gsi_trans_info *trans_info = &channel->trans_info; 785 786 gsi_trans_pool_exit(&trans_info->sg_pool); 787 kfree(trans_info->trans); 788 kfree(trans_info->map); 789 } 790