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1// SPDX-License-Identifier: GPL-2.02 3/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.4 * Copyright (C) 2019-2024 Linaro Ltd.5 */6 7#include <linux/bitfield.h>8#include <linux/bits.h>9#include <linux/dma-direction.h>10#include <linux/refcount.h>11#include <linux/scatterlist.h>12#include <linux/types.h>13 14#include "gsi.h"15#include "gsi_private.h"16#include "gsi_trans.h"17#include "ipa_cmd.h"18#include "ipa_data.h"19#include "ipa_gsi.h"20 21/**22 * DOC: GSI Transactions23 *24 * A GSI transaction abstracts the behavior of a GSI channel by representing25 * 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 immediate27 * command.) Most details of interaction with the GSI hardware are managed28 * by the GSI transaction core, allowing users to simply describe operations29 * to be performed. When a transaction has completed a callback function30 * (dependent on the type of endpoint associated with the channel) allows31 * cleanup of resources associated with the transaction.32 *33 * To perform an operation (or set of them), a user of the GSI transaction34 * interface allocates a transaction, indicating the number of TREs required35 * (one per operation). If sufficient TREs are available, they are reserved36 * for use in the transaction and the allocation succeeds. This way37 * exhaustion of the available TREs in a channel ring is detected as early38 * as possible. Any other resources that might be needed to complete a39 * transaction are also allocated when the transaction is allocated.40 *41 * Operations performed as part of a transaction are represented in an array42 * of Linux scatterlist structures, allocated with the transaction. These43 * scatterlist structures are initialized by "adding" operations to the44 * transaction. If a buffer in an operation must be mapped for DMA, this is45 * done at the time it is added to the transaction. It is possible for a46 * mapping error to occur when an operation is added. In this case the47 * transaction should simply be freed; this correctly releases resources48 * associated with the transaction.49 *50 * Once all operations have been successfully added to a transaction, the51 * transaction is committed. Committing transfers ownership of the entire52 * transaction to the GSI transaction core. The GSI transaction code53 * formats the content of the scatterlist array into the channel ring54 * 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 the57 * GSI hardware has completed it. Because transfers described by TREs are58 * performed strictly in order, signaling the completion of just the last59 * TRE in the transaction is sufficient to indicate the full transaction60 * is complete.61 *62 * When a transaction is complete, ipa_gsi_trans_complete() is called by the63 * GSI code into the IPA layer, allowing it to perform any final cleanup64 * 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 less101 * than the maximum number that will be requested in a102 * single allocation), we can always satisfy requests without103 * 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 guarantee131 * allocations will succeed. The immediate commands in a transaction can132 * require up to max_alloc elements from the pool. But we only allow133 * 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 pages154 * sufficient to satisfy our request. Round up our requested155 * size to avoid any unused space in the allocation. This way156 * gsi_trans_pool_exit_dma() can assume the total allocated157 * 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 bool302gsi_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 void318gsi_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[] and401 * (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 allocated417 * using dma_alloc_coherent(). We therefore do *not* map them418 * 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 tells422 * gsi_trans_complete() to skip the unmapping step.423 *424 * The only things we use directly in a command scatter/gather425 * entry are the DMA address and length. We still need the SG426 * table flags to be maintained though, so assign a NULL page427 * 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 code536 * @trans: Transaction to commit537 * @ring_db: Whether to tell the hardware about these queued transfers538 *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 to542 * pending state. Finally, updates the channel ring pointer and optionally543 * 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 while561 * filling them we'll switch to the beginning to finish.562 * If there is no info array we're doing a simple data563 * 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 else609 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 of718 * outstanding transactions and their resources. A transaction719 * allocation succeeds only if the TREs available are sufficient720 * 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 limit728 * it to something a little less than that). By allocating a729 * power-of-two number of transactions we can use an index730 * 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 caused745 * the event (which will be the last one used by the transaction).746 * Each entry in this map records the transaction associated747 * 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 data757 * transfers implemented by the transaction. Each scatterlist758 * element is used to fill a single TRE when the transaction is759 * committed. So we need as many scatterlist elements as the760 * 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