1// SPDX-License-Identifier: GPL-2.0 2 3/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved. 4 * Copyright (C) 2019-2022 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 operations in a single structure. 26 * (A "operation" 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 operations 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 an operation (or set of them), a user of the GSI transaction 34 * interface allocates a transaction, indicating the number of TREs required 35 * (one per operation). 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 as early 38 * as possible. Any other resources that might be needed to complete a 39 * transaction are also allocated when the transaction is allocated. 40 * 41 * Operations performed as part of a transaction are represented in an array 42 * of Linux scatterlist structures, allocated with the transaction. These 43 * scatterlist structures are initialized by "adding" operations to the 44 * transaction. If a buffer in an operation must be mapped for DMA, this is 45 * done at the time it is added to the transaction. It is possible for a 46 * mapping error to occur when an operation is added. In this case the 47 * transaction should simply be freed; this correctly releases resources 48 * associated with the transaction. 49 * 50 * Once all operations have been successfully added to a transaction, the 51 * transaction is committed. Committing transfers ownership of the entire 52 * transaction to the GSI transaction core. The GSI transaction code 53 * formats the content of the scatterlist array into the channel ring 54 * buffer and informs the hardware that new TREs are available to process. 55 * 56 * The last TRE in each transaction is marked to interrupt the AP when the 57 * GSI hardware has completed it. Because transfers described by TREs are 58 * performed strictly in order, signaling the completion of just the last 59 * TRE in the transaction is sufficient to indicate the full transaction 60 * is complete. 61 * 62 * When a transaction is complete, ipa_gsi_trans_complete() is called by the 63 * GSI code into the IPA layer, allowing it to perform any final cleanup 64 * required before the transaction is freed. 65 */ 66 67/* Hardware values representing a transfer element type */ 68enum gsi_tre_type { 69 GSI_RE_XFER = 0x2, 70 GSI_RE_IMMD_CMD = 0x3, 71}; 72 73/* An entry in a channel ring */ 74struct gsi_tre { 75 __le64 addr; /* DMA address */ 76 __le16 len_opcode; /* length in bytes or enum IPA_CMD_* */ 77 __le16 reserved; 78 __le32 flags; /* TRE_FLAGS_* */ 79}; 80 81/* gsi_tre->flags mask values (in CPU byte order) */ 82#define TRE_FLAGS_CHAIN_FMASK GENMASK(0, 0) 83#define TRE_FLAGS_IEOT_FMASK GENMASK(9, 9) 84#define TRE_FLAGS_BEI_FMASK GENMASK(10, 10) 85#define TRE_FLAGS_TYPE_FMASK GENMASK(23, 16) 86 87int gsi_trans_pool_init(struct gsi_trans_pool *pool, size_t size, u32 count, 88 u32 max_alloc) 89{ 90 size_t alloc_size; 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 alloc_size = size_mul(count + max_alloc - 1, size); 108 alloc_size = kmalloc_size_roundup(alloc_size); 109 virt = kzalloc(alloc_size, GFP_KERNEL); 110 if (!virt) 111 return -ENOMEM; 112 113 pool->base = virt; 114 /* If the allocator gave us any extra memory, use it */ 115 pool->count = alloc_size / size; 116 pool->free = 0; 117 pool->max_alloc = max_alloc; 118 pool->size = size; 119 pool->addr = 0; /* Only used for DMA pools */ 120 121 return 0; 122} 123 124void gsi_trans_pool_exit(struct gsi_trans_pool *pool) 125{ 126 kfree(pool->base); 127 memset(pool, 0, sizeof(*pool)); 128} 129 130/* Home-grown DMA pool. This way we can preallocate the pool, and guarantee 131 * allocations will succeed. The immediate commands in a transaction can 132 * require up to max_alloc elements from the pool. But we only allow 133 * allocation of a single element from a DMA pool at a time. 134 */ 135int gsi_trans_pool_init_dma(struct device *dev, struct gsi_trans_pool *pool, 136 size_t size, u32 count, u32 max_alloc) 137{ 138 size_t total_size; 139 dma_addr_t addr; 140 void *virt; 141 142 if (!size) 143 return -EINVAL; 144 if (count < max_alloc) 145 return -EINVAL; 146 if (!max_alloc) 147 return -EINVAL; 148 149 /* Don't let allocations cross a power-of-two boundary */ 150 size = __roundup_pow_of_two(size); 151 total_size = (count + max_alloc - 1) * size; 152 153 /* The allocator will give us a power-of-2 number of pages 154 * sufficient to satisfy our request. Round up our requested 155 * size to avoid any unused space in the allocation. This way 156 * gsi_trans_pool_exit_dma() can assume the total allocated 157 * size is exactly (count * size). 158 */ 159 total_size = PAGE_SIZE << get_order(total_size); 160 161 virt = dma_alloc_coherent(dev, total_size, &addr, GFP_KERNEL); 162 if (!virt) 163 return -ENOMEM; 164 165 pool->base = virt; 166 pool->count = total_size / size; 167 pool->free = 0; 168 pool->size = size; 169 pool->max_alloc = max_alloc; 170 pool->addr = addr; 171 172 return 0; 173} 174 175void gsi_trans_pool_exit_dma(struct device *dev, struct gsi_trans_pool *pool) 176{ 177 size_t total_size = pool->count * pool->size; 178 179 dma_free_coherent(dev, total_size, pool->base, pool->addr); 180 memset(pool, 0, sizeof(*pool)); 181} 182 183/* Return the byte offset of the next free entry in the pool */ 184static u32 gsi_trans_pool_alloc_common(struct gsi_trans_pool *pool, u32 count) 185{ 186 u32 offset; 187 188 WARN_ON(!count); 189 WARN_ON(count > pool->max_alloc); 190 191 /* Allocate from beginning if wrap would occur */ 192 if (count > pool->count - pool->free) 193 pool->free = 0; 194 195 offset = pool->free * pool->size; 196 pool->free += count; 197 memset(pool->base + offset, 0, count * pool->size); 198 199 return offset; 200} 201 202/* Allocate a contiguous block of zeroed entries from a pool */ 203void *gsi_trans_pool_alloc(struct gsi_trans_pool *pool, u32 count) 204{ 205 return pool->base + gsi_trans_pool_alloc_common(pool, count); 206} 207 208/* Allocate a single zeroed entry from a DMA pool */ 209void *gsi_trans_pool_alloc_dma(struct gsi_trans_pool *pool, dma_addr_t *addr) 210{ 211 u32 offset = gsi_trans_pool_alloc_common(pool, 1); 212 213 *addr = pool->addr + offset; 214 215 return pool->base + offset; 216} 217 218/* Map a TRE ring entry index to the transaction it is associated with */ 219static void gsi_trans_map(struct gsi_trans *trans, u32 index) 220{ 221 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 222 223 /* The completion event will indicate the last TRE used */ 224 index += trans->used_count - 1; 225 226 /* Note: index *must* be used modulo the ring count here */ 227 channel->trans_info.map[index % channel->tre_ring.count] = trans; 228} 229 230/* Return the transaction mapped to a given ring entry */ 231struct gsi_trans * 232gsi_channel_trans_mapped(struct gsi_channel *channel, u32 index) 233{ 234 /* Note: index *must* be used modulo the ring count here */ 235 return channel->trans_info.map[index % channel->tre_ring.count]; 236} 237 238/* Return the oldest completed transaction for a channel (or null) */ 239struct gsi_trans *gsi_channel_trans_complete(struct gsi_channel *channel) 240{ 241 struct gsi_trans_info *trans_info = &channel->trans_info; 242 u16 trans_id = trans_info->completed_id; 243 244 if (trans_id == trans_info->pending_id) { 245 gsi_channel_update(channel); 246 if (trans_id == trans_info->pending_id) 247 return NULL; 248 } 249 250 return &trans_info->trans[trans_id %= channel->tre_count]; 251} 252 253/* Move a transaction from allocated to committed state */ 254static void gsi_trans_move_committed(struct gsi_trans *trans) 255{ 256 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 257 struct gsi_trans_info *trans_info = &channel->trans_info; 258 259 /* This allocated transaction is now committed */ 260 trans_info->allocated_id++; 261} 262 263/* Move committed transactions to pending state */ 264static void gsi_trans_move_pending(struct gsi_trans *trans) 265{ 266 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 267 struct gsi_trans_info *trans_info = &channel->trans_info; 268 u16 trans_index = trans - &trans_info->trans[0]; 269 u16 delta; 270 271 /* These committed transactions are now pending */ 272 delta = trans_index - trans_info->committed_id + 1; 273 trans_info->committed_id += delta % channel->tre_count; 274} 275 276/* Move pending transactions to completed state */ 277void gsi_trans_move_complete(struct gsi_trans *trans) 278{ 279 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 280 struct gsi_trans_info *trans_info = &channel->trans_info; 281 u16 trans_index = trans - trans_info->trans; 282 u16 delta; 283 284 /* These pending transactions are now completed */ 285 delta = trans_index - trans_info->pending_id + 1; 286 delta %= channel->tre_count; 287 trans_info->pending_id += delta; 288} 289 290/* Move a transaction from completed to polled state */ 291void gsi_trans_move_polled(struct gsi_trans *trans) 292{ 293 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 294 struct gsi_trans_info *trans_info = &channel->trans_info; 295 296 /* This completed transaction is now polled */ 297 trans_info->completed_id++; 298} 299 300/* Reserve some number of TREs on a channel. Returns true if successful */ 301static bool 302gsi_trans_tre_reserve(struct gsi_trans_info *trans_info, u32 tre_count) 303{ 304 int avail = atomic_read(&trans_info->tre_avail); 305 int new; 306 307 do { 308 new = avail - (int)tre_count; 309 if (unlikely(new < 0)) 310 return false; 311 } while (!atomic_try_cmpxchg(&trans_info->tre_avail, &avail, new)); 312 313 return true; 314} 315 316/* Release previously-reserved TRE entries to a channel */ 317static void 318gsi_trans_tre_release(struct gsi_trans_info *trans_info, u32 tre_count) 319{ 320 atomic_add(tre_count, &trans_info->tre_avail); 321} 322 323/* Return true if no transactions are allocated, false otherwise */ 324bool gsi_channel_trans_idle(struct gsi *gsi, u32 channel_id) 325{ 326 u32 tre_max = gsi_channel_tre_max(gsi, channel_id); 327 struct gsi_trans_info *trans_info; 328 329 trans_info = &gsi->channel[channel_id].trans_info; 330 331 return atomic_read(&trans_info->tre_avail) == tre_max; 332} 333 334/* Allocate a GSI transaction on a channel */ 335struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id, 336 u32 tre_count, 337 enum dma_data_direction direction) 338{ 339 struct gsi_channel *channel = &gsi->channel[channel_id]; 340 struct gsi_trans_info *trans_info; 341 struct gsi_trans *trans; 342 u16 trans_index; 343 344 if (WARN_ON(tre_count > channel->trans_tre_max)) 345 return NULL; 346 347 trans_info = &channel->trans_info; 348 349 /* If we can't reserve the TREs for the transaction, we're done */ 350 if (!gsi_trans_tre_reserve(trans_info, tre_count)) 351 return NULL; 352 353 trans_index = trans_info->free_id % channel->tre_count; 354 trans = &trans_info->trans[trans_index]; 355 memset(trans, 0, sizeof(*trans)); 356 357 /* Initialize non-zero fields in the transaction */ 358 trans->gsi = gsi; 359 trans->channel_id = channel_id; 360 trans->rsvd_count = tre_count; 361 init_completion(&trans->completion); 362 363 /* Allocate the scatterlist */ 364 trans->sgl = gsi_trans_pool_alloc(&trans_info->sg_pool, tre_count); 365 sg_init_marker(trans->sgl, tre_count); 366 367 trans->direction = direction; 368 refcount_set(&trans->refcount, 1); 369 370 /* This free transaction is now allocated */ 371 trans_info->free_id++; 372 373 return trans; 374} 375 376/* Free a previously-allocated transaction */ 377void gsi_trans_free(struct gsi_trans *trans) 378{ 379 struct gsi_trans_info *trans_info; 380 381 if (!refcount_dec_and_test(&trans->refcount)) 382 return; 383 384 /* Unused transactions are allocated but never committed, pending, 385 * completed, or polled. 386 */ 387 trans_info = &trans->gsi->channel[trans->channel_id].trans_info; 388 if (!trans->used_count) { 389 trans_info->allocated_id++; 390 trans_info->committed_id++; 391 trans_info->pending_id++; 392 trans_info->completed_id++; 393 } else { 394 ipa_gsi_trans_release(trans); 395 } 396 397 /* This transaction is now free */ 398 trans_info->polled_id++; 399 400 /* Releasing the reserved TREs implicitly frees the sgl[] and 401 * (if present) info[] arrays, plus the transaction itself. 402 */ 403 gsi_trans_tre_release(trans_info, trans->rsvd_count); 404} 405 406/* Add an immediate command to a transaction */ 407void gsi_trans_cmd_add(struct gsi_trans *trans, void *buf, u32 size, 408 dma_addr_t addr, enum ipa_cmd_opcode opcode) 409{ 410 u32 which = trans->used_count++; 411 struct scatterlist *sg; 412 413 WARN_ON(which >= trans->rsvd_count); 414 415 /* Commands are quite different from data transfer requests. 416 * Their payloads come from a pool whose memory is allocated 417 * using dma_alloc_coherent(). We therefore do *not* map them 418 * for DMA (unlike what we do for pages and skbs). 419 * 420 * When a transaction completes, the SGL is normally unmapped. 421 * A command transaction has direction DMA_NONE, which tells 422 * gsi_trans_complete() to skip the unmapping step. 423 * 424 * The only things we use directly in a command scatter/gather 425 * entry are the DMA address and length. We still need the SG 426 * table flags to be maintained though, so assign a NULL page 427 * pointer for that purpose. 428 */ 429 sg = &trans->sgl[which]; 430 sg_assign_page(sg, NULL); 431 sg_dma_address(sg) = addr; 432 sg_dma_len(sg) = size; 433 434 trans->cmd_opcode[which] = opcode; 435} 436 437/* Add a page transfer to a transaction. It will fill the only TRE. */ 438int gsi_trans_page_add(struct gsi_trans *trans, struct page *page, u32 size, 439 u32 offset) 440{ 441 struct scatterlist *sg = &trans->sgl[0]; 442 int ret; 443 444 if (WARN_ON(trans->rsvd_count != 1)) 445 return -EINVAL; 446 if (WARN_ON(trans->used_count)) 447 return -EINVAL; 448 449 sg_set_page(sg, page, size, offset); 450 ret = dma_map_sg(trans->gsi->dev, sg, 1, trans->direction); 451 if (!ret) 452 return -ENOMEM; 453 454 trans->used_count++; /* Transaction now owns the (DMA mapped) page */ 455 456 return 0; 457} 458 459/* Add an SKB transfer to a transaction. No other TREs will be used. */ 460int gsi_trans_skb_add(struct gsi_trans *trans, struct sk_buff *skb) 461{ 462 struct scatterlist *sg = &trans->sgl[0]; 463 u32 used_count; 464 int ret; 465 466 if (WARN_ON(trans->rsvd_count != 1)) 467 return -EINVAL; 468 if (WARN_ON(trans->used_count)) 469 return -EINVAL; 470 471 /* skb->len will not be 0 (checked early) */ 472 ret = skb_to_sgvec(skb, sg, 0, skb->len); 473 if (ret < 0) 474 return ret; 475 used_count = ret; 476 477 ret = dma_map_sg(trans->gsi->dev, sg, used_count, trans->direction); 478 if (!ret) 479 return -ENOMEM; 480 481 /* Transaction now owns the (DMA mapped) skb */ 482 trans->used_count += used_count; 483 484 return 0; 485} 486 487/* Compute the length/opcode value to use for a TRE */ 488static __le16 gsi_tre_len_opcode(enum ipa_cmd_opcode opcode, u32 len) 489{ 490 return opcode == IPA_CMD_NONE ? cpu_to_le16((u16)len) 491 : cpu_to_le16((u16)opcode); 492} 493 494/* Compute the flags value to use for a given TRE */ 495static __le32 gsi_tre_flags(bool last_tre, bool bei, enum ipa_cmd_opcode opcode) 496{ 497 enum gsi_tre_type tre_type; 498 u32 tre_flags; 499 500 tre_type = opcode == IPA_CMD_NONE ? GSI_RE_XFER : GSI_RE_IMMD_CMD; 501 tre_flags = u32_encode_bits(tre_type, TRE_FLAGS_TYPE_FMASK); 502 503 /* Last TRE contains interrupt flags */ 504 if (last_tre) { 505 /* All transactions end in a transfer completion interrupt */ 506 tre_flags |= TRE_FLAGS_IEOT_FMASK; 507 /* Don't interrupt when outbound commands are acknowledged */ 508 if (bei) 509 tre_flags |= TRE_FLAGS_BEI_FMASK; 510 } else { /* All others indicate there's more to come */ 511 tre_flags |= TRE_FLAGS_CHAIN_FMASK; 512 } 513 514 return cpu_to_le32(tre_flags); 515} 516 517static void gsi_trans_tre_fill(struct gsi_tre *dest_tre, dma_addr_t addr, 518 u32 len, bool last_tre, bool bei, 519 enum ipa_cmd_opcode opcode) 520{ 521 struct gsi_tre tre; 522 523 tre.addr = cpu_to_le64(addr); 524 tre.len_opcode = gsi_tre_len_opcode(opcode, len); 525 tre.reserved = 0; 526 tre.flags = gsi_tre_flags(last_tre, bei, opcode); 527 528 /* ARM64 can write 16 bytes as a unit with a single instruction. 529 * Doing the assignment this way is an attempt to make that happen. 530 */ 531 *dest_tre = tre; 532} 533 534/** 535 * __gsi_trans_commit() - Common GSI transaction commit code 536 * @trans: Transaction to commit 537 * @ring_db: Whether to tell the hardware about these queued transfers 538 * 539 * Formats channel ring TRE entries based on the content of the scatterlist. 540 * Maps a transaction pointer to the last ring entry used for the transaction, 541 * so it can be recovered when it completes. Moves the transaction to 542 * pending state. Finally, updates the channel ring pointer and optionally 543 * rings the doorbell. 544 */ 545static void __gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 546{ 547 struct gsi_channel *channel = &trans->gsi->channel[trans->channel_id]; 548 struct gsi_ring *tre_ring = &channel->tre_ring; 549 enum ipa_cmd_opcode opcode = IPA_CMD_NONE; 550 bool bei = channel->toward_ipa; 551 struct gsi_tre *dest_tre; 552 struct scatterlist *sg; 553 u32 byte_count = 0; 554 u8 *cmd_opcode; 555 u32 avail; 556 u32 i; 557 558 WARN_ON(!trans->used_count); 559 560 /* Consume the entries. If we cross the end of the ring while 561 * filling them we'll switch to the beginning to finish. 562 * If there is no info array we're doing a simple data 563 * transfer request, whose opcode is IPA_CMD_NONE. 564 */ 565 cmd_opcode = channel->command ? &trans->cmd_opcode[0] : NULL; 566 avail = tre_ring->count - tre_ring->index % tre_ring->count; 567 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 568 for_each_sg(trans->sgl, sg, trans->used_count, i) { 569 bool last_tre = i == trans->used_count - 1; 570 dma_addr_t addr = sg_dma_address(sg); 571 u32 len = sg_dma_len(sg); 572 573 byte_count += len; 574 if (!avail--) 575 dest_tre = gsi_ring_virt(tre_ring, 0); 576 if (cmd_opcode) 577 opcode = *cmd_opcode++; 578 579 gsi_trans_tre_fill(dest_tre, addr, len, last_tre, bei, opcode); 580 dest_tre++; 581 } 582 /* Associate the TRE with the transaction */ 583 gsi_trans_map(trans, tre_ring->index); 584 585 tre_ring->index += trans->used_count; 586 587 trans->len = byte_count; 588 if (channel->toward_ipa) 589 gsi_trans_tx_committed(trans); 590 591 gsi_trans_move_committed(trans); 592 593 /* Ring doorbell if requested, or if all TREs are allocated */ 594 if (ring_db || !atomic_read(&channel->trans_info.tre_avail)) { 595 /* Report what we're handing off to hardware for TX channels */ 596 if (channel->toward_ipa) 597 gsi_trans_tx_queued(trans); 598 gsi_trans_move_pending(trans); 599 gsi_channel_doorbell(channel); 600 } 601} 602 603/* Commit a GSI transaction */ 604void gsi_trans_commit(struct gsi_trans *trans, bool ring_db) 605{ 606 if (trans->used_count) 607 __gsi_trans_commit(trans, ring_db); 608 else 609 gsi_trans_free(trans); 610} 611 612/* Commit a GSI transaction and wait for it to complete */ 613void gsi_trans_commit_wait(struct gsi_trans *trans) 614{ 615 if (!trans->used_count) 616 goto out_trans_free; 617 618 refcount_inc(&trans->refcount); 619 620 __gsi_trans_commit(trans, true); 621 622 wait_for_completion(&trans->completion); 623 624out_trans_free: 625 gsi_trans_free(trans); 626} 627 628/* Process the completion of a transaction; called while polling */ 629void gsi_trans_complete(struct gsi_trans *trans) 630{ 631 /* If the entire SGL was mapped when added, unmap it now */ 632 if (trans->direction != DMA_NONE) 633 dma_unmap_sg(trans->gsi->dev, trans->sgl, trans->used_count, 634 trans->direction); 635 636 ipa_gsi_trans_complete(trans); 637 638 complete(&trans->completion); 639 640 gsi_trans_free(trans); 641} 642 643/* Cancel a channel's pending transactions */ 644void gsi_channel_trans_cancel_pending(struct gsi_channel *channel) 645{ 646 struct gsi_trans_info *trans_info = &channel->trans_info; 647 u16 trans_id = trans_info->pending_id; 648 649 /* channel->gsi->mutex is held by caller */ 650 651 /* If there are no pending transactions, we're done */ 652 if (trans_id == trans_info->committed_id) 653 return; 654 655 /* Mark all pending transactions cancelled */ 656 do { 657 struct gsi_trans *trans; 658 659 trans = &trans_info->trans[trans_id % channel->tre_count]; 660 trans->cancelled = true; 661 } while (++trans_id != trans_info->committed_id); 662 663 /* All pending transactions are now completed */ 664 trans_info->pending_id = trans_info->committed_id; 665 666 /* Schedule NAPI polling to complete the cancelled transactions */ 667 napi_schedule(&channel->napi); 668} 669 670/* Issue a command to read a single byte from a channel */ 671int gsi_trans_read_byte(struct gsi *gsi, u32 channel_id, dma_addr_t addr) 672{ 673 struct gsi_channel *channel = &gsi->channel[channel_id]; 674 struct gsi_ring *tre_ring = &channel->tre_ring; 675 struct gsi_trans_info *trans_info; 676 struct gsi_tre *dest_tre; 677 678 trans_info = &channel->trans_info; 679 680 /* First reserve the TRE, if possible */ 681 if (!gsi_trans_tre_reserve(trans_info, 1)) 682 return -EBUSY; 683 684 /* Now fill the reserved TRE and tell the hardware */ 685 686 dest_tre = gsi_ring_virt(tre_ring, tre_ring->index); 687 gsi_trans_tre_fill(dest_tre, addr, 1, true, false, IPA_CMD_NONE); 688 689 tre_ring->index++; 690 gsi_channel_doorbell(channel); 691 692 return 0; 693} 694 695/* Mark a gsi_trans_read_byte() request done */ 696void gsi_trans_read_byte_done(struct gsi *gsi, u32 channel_id) 697{ 698 struct gsi_channel *channel = &gsi->channel[channel_id]; 699 700 gsi_trans_tre_release(&channel->trans_info, 1); 701} 702 703/* Initialize a channel's GSI transaction info */ 704int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id) 705{ 706 struct gsi_channel *channel = &gsi->channel[channel_id]; 707 u32 tre_count = channel->tre_count; 708 struct gsi_trans_info *trans_info; 709 u32 tre_max; 710 int ret; 711 712 /* Ensure the size of a channel element is what's expected */ 713 BUILD_BUG_ON(sizeof(struct gsi_tre) != GSI_RING_ELEMENT_SIZE); 714 715 trans_info = &channel->trans_info; 716 717 /* The tre_avail field is what ultimately limits the number of 718 * outstanding transactions and their resources. A transaction 719 * allocation succeeds only if the TREs available are sufficient 720 * for what the transaction might need. 721 */ 722 tre_max = gsi_channel_tre_max(channel->gsi, channel_id); 723 atomic_set(&trans_info->tre_avail, tre_max); 724 725 /* We can't use more TREs than the number available in the ring. 726 * This limits the number of transactions that can be outstanding. 727 * Worst case is one TRE per transaction (but we actually limit 728 * it to something a little less than that). By allocating a 729 * power-of-two number of transactions we can use an index 730 * modulo that number to determine the next one that's free. 731 * Transactions are allocated one at a time. 732 */ 733 trans_info->trans = kcalloc(tre_count, sizeof(*trans_info->trans), 734 GFP_KERNEL); 735 if (!trans_info->trans) 736 return -ENOMEM; 737 trans_info->free_id = 0; /* all modulo channel->tre_count */ 738 trans_info->allocated_id = 0; 739 trans_info->committed_id = 0; 740 trans_info->pending_id = 0; 741 trans_info->completed_id = 0; 742 trans_info->polled_id = 0; 743 744 /* A completion event contains a pointer to the TRE that caused 745 * the event (which will be the last one used by the transaction). 746 * Each entry in this map records the transaction associated 747 * with a corresponding completed TRE. 748 */ 749 trans_info->map = kcalloc(tre_count, sizeof(*trans_info->map), 750 GFP_KERNEL); 751 if (!trans_info->map) { 752 ret = -ENOMEM; 753 goto err_trans_free; 754 } 755 756 /* A transaction uses a scatterlist array to represent the data 757 * transfers implemented by the transaction. Each scatterlist 758 * element is used to fill a single TRE when the transaction is 759 * committed. So we need as many scatterlist elements as the 760 * maximum number of TREs that can be outstanding. 761 */ 762 ret = gsi_trans_pool_init(&trans_info->sg_pool, 763 sizeof(struct scatterlist), 764 tre_max, channel->trans_tre_max); 765 if (ret) 766 goto err_map_free; 767 768 769 return 0; 770 771err_map_free: 772 kfree(trans_info->map); 773err_trans_free: 774 kfree(trans_info->trans); 775 776 dev_err(gsi->dev, "error %d initializing channel %u transactions\n", 777 ret, channel_id); 778 779 return ret; 780} 781 782/* Inverse of gsi_channel_trans_init() */ 783void gsi_channel_trans_exit(struct gsi_channel *channel) 784{ 785 struct gsi_trans_info *trans_info = &channel->trans_info; 786 787 gsi_trans_pool_exit(&trans_info->sg_pool); 788 kfree(trans_info->trans); 789 kfree(trans_info->map); 790} 791