linux/drivers/firewire/core-iso.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Isochronous I/O functionality:
   4 *   - Isochronous DMA context management
   5 *   - Isochronous bus resource management (channels, bandwidth), client side
   6 *
   7 * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
   8 */
   9
  10#include <linux/dma-mapping.h>
  11#include <linux/errno.h>
  12#include <linux/firewire.h>
  13#include <linux/firewire-constants.h>
  14#include <linux/kernel.h>
  15#include <linux/mm.h>
  16#include <linux/slab.h>
  17#include <linux/spinlock.h>
  18#include <linux/vmalloc.h>
  19#include <linux/export.h>
  20
  21#include <asm/byteorder.h>
  22
  23#include "core.h"
  24
  25/*
  26 * Isochronous DMA context management
  27 */
  28
  29int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
  30{
  31        int i;
  32
  33        buffer->page_count = 0;
  34        buffer->page_count_mapped = 0;
  35        buffer->pages = kmalloc_array(page_count, sizeof(buffer->pages[0]),
  36                                      GFP_KERNEL);
  37        if (buffer->pages == NULL)
  38                return -ENOMEM;
  39
  40        for (i = 0; i < page_count; i++) {
  41                buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  42                if (buffer->pages[i] == NULL)
  43                        break;
  44        }
  45        buffer->page_count = i;
  46        if (i < page_count) {
  47                fw_iso_buffer_destroy(buffer, NULL);
  48                return -ENOMEM;
  49        }
  50
  51        return 0;
  52}
  53
  54int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
  55                          enum dma_data_direction direction)
  56{
  57        dma_addr_t address;
  58        int i;
  59
  60        buffer->direction = direction;
  61
  62        for (i = 0; i < buffer->page_count; i++) {
  63                address = dma_map_page(card->device, buffer->pages[i],
  64                                       0, PAGE_SIZE, direction);
  65                if (dma_mapping_error(card->device, address))
  66                        break;
  67
  68                set_page_private(buffer->pages[i], address);
  69        }
  70        buffer->page_count_mapped = i;
  71        if (i < buffer->page_count)
  72                return -ENOMEM;
  73
  74        return 0;
  75}
  76
  77int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  78                       int page_count, enum dma_data_direction direction)
  79{
  80        int ret;
  81
  82        ret = fw_iso_buffer_alloc(buffer, page_count);
  83        if (ret < 0)
  84                return ret;
  85
  86        ret = fw_iso_buffer_map_dma(buffer, card, direction);
  87        if (ret < 0)
  88                fw_iso_buffer_destroy(buffer, card);
  89
  90        return ret;
  91}
  92EXPORT_SYMBOL(fw_iso_buffer_init);
  93
  94int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,
  95                          struct vm_area_struct *vma)
  96{
  97        return vm_map_pages_zero(vma, buffer->pages,
  98                                        buffer->page_count);
  99}
 100
 101void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 102                           struct fw_card *card)
 103{
 104        int i;
 105        dma_addr_t address;
 106
 107        for (i = 0; i < buffer->page_count_mapped; i++) {
 108                address = page_private(buffer->pages[i]);
 109                dma_unmap_page(card->device, address,
 110                               PAGE_SIZE, buffer->direction);
 111        }
 112        for (i = 0; i < buffer->page_count; i++)
 113                __free_page(buffer->pages[i]);
 114
 115        kfree(buffer->pages);
 116        buffer->pages = NULL;
 117        buffer->page_count = 0;
 118        buffer->page_count_mapped = 0;
 119}
 120EXPORT_SYMBOL(fw_iso_buffer_destroy);
 121
 122/* Convert DMA address to offset into virtually contiguous buffer. */
 123size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 124{
 125        size_t i;
 126        dma_addr_t address;
 127        ssize_t offset;
 128
 129        for (i = 0; i < buffer->page_count; i++) {
 130                address = page_private(buffer->pages[i]);
 131                offset = (ssize_t)completed - (ssize_t)address;
 132                if (offset > 0 && offset <= PAGE_SIZE)
 133                        return (i << PAGE_SHIFT) + offset;
 134        }
 135
 136        return 0;
 137}
 138
 139struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 140                int type, int channel, int speed, size_t header_size,
 141                fw_iso_callback_t callback, void *callback_data)
 142{
 143        struct fw_iso_context *ctx;
 144
 145        ctx = card->driver->allocate_iso_context(card,
 146                                                 type, channel, header_size);
 147        if (IS_ERR(ctx))
 148                return ctx;
 149
 150        ctx->card = card;
 151        ctx->type = type;
 152        ctx->channel = channel;
 153        ctx->speed = speed;
 154        ctx->header_size = header_size;
 155        ctx->callback.sc = callback;
 156        ctx->callback_data = callback_data;
 157
 158        return ctx;
 159}
 160EXPORT_SYMBOL(fw_iso_context_create);
 161
 162void fw_iso_context_destroy(struct fw_iso_context *ctx)
 163{
 164        ctx->card->driver->free_iso_context(ctx);
 165}
 166EXPORT_SYMBOL(fw_iso_context_destroy);
 167
 168int fw_iso_context_start(struct fw_iso_context *ctx,
 169                         int cycle, int sync, int tags)
 170{
 171        return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 172}
 173EXPORT_SYMBOL(fw_iso_context_start);
 174
 175int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
 176{
 177        return ctx->card->driver->set_iso_channels(ctx, channels);
 178}
 179
 180int fw_iso_context_queue(struct fw_iso_context *ctx,
 181                         struct fw_iso_packet *packet,
 182                         struct fw_iso_buffer *buffer,
 183                         unsigned long payload)
 184{
 185        return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
 186}
 187EXPORT_SYMBOL(fw_iso_context_queue);
 188
 189void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 190{
 191        ctx->card->driver->flush_queue_iso(ctx);
 192}
 193EXPORT_SYMBOL(fw_iso_context_queue_flush);
 194
 195int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 196{
 197        return ctx->card->driver->flush_iso_completions(ctx);
 198}
 199EXPORT_SYMBOL(fw_iso_context_flush_completions);
 200
 201int fw_iso_context_stop(struct fw_iso_context *ctx)
 202{
 203        return ctx->card->driver->stop_iso(ctx);
 204}
 205EXPORT_SYMBOL(fw_iso_context_stop);
 206
 207/*
 208 * Isochronous bus resource management (channels, bandwidth), client side
 209 */
 210
 211static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 212                            int bandwidth, bool allocate)
 213{
 214        int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 215        __be32 data[2];
 216
 217        /*
 218         * On a 1394a IRM with low contention, try < 1 is enough.
 219         * On a 1394-1995 IRM, we need at least try < 2.
 220         * Let's just do try < 5.
 221         */
 222        for (try = 0; try < 5; try++) {
 223                new = allocate ? old - bandwidth : old + bandwidth;
 224                if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 225                        return -EBUSY;
 226
 227                data[0] = cpu_to_be32(old);
 228                data[1] = cpu_to_be32(new);
 229                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 230                                irm_id, generation, SCODE_100,
 231                                CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 232                                data, 8)) {
 233                case RCODE_GENERATION:
 234                        /* A generation change frees all bandwidth. */
 235                        return allocate ? -EAGAIN : bandwidth;
 236
 237                case RCODE_COMPLETE:
 238                        if (be32_to_cpup(data) == old)
 239                                return bandwidth;
 240
 241                        old = be32_to_cpup(data);
 242                        /* Fall through. */
 243                }
 244        }
 245
 246        return -EIO;
 247}
 248
 249static int manage_channel(struct fw_card *card, int irm_id, int generation,
 250                u32 channels_mask, u64 offset, bool allocate)
 251{
 252        __be32 bit, all, old;
 253        __be32 data[2];
 254        int channel, ret = -EIO, retry = 5;
 255
 256        old = all = allocate ? cpu_to_be32(~0) : 0;
 257
 258        for (channel = 0; channel < 32; channel++) {
 259                if (!(channels_mask & 1 << channel))
 260                        continue;
 261
 262                ret = -EBUSY;
 263
 264                bit = cpu_to_be32(1 << (31 - channel));
 265                if ((old & bit) != (all & bit))
 266                        continue;
 267
 268                data[0] = old;
 269                data[1] = old ^ bit;
 270                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 271                                           irm_id, generation, SCODE_100,
 272                                           offset, data, 8)) {
 273                case RCODE_GENERATION:
 274                        /* A generation change frees all channels. */
 275                        return allocate ? -EAGAIN : channel;
 276
 277                case RCODE_COMPLETE:
 278                        if (data[0] == old)
 279                                return channel;
 280
 281                        old = data[0];
 282
 283                        /* Is the IRM 1394a-2000 compliant? */
 284                        if ((data[0] & bit) == (data[1] & bit))
 285                                continue;
 286
 287                        /* fall through - It's a 1394-1995 IRM, retry. */
 288                default:
 289                        if (retry) {
 290                                retry--;
 291                                channel--;
 292                        } else {
 293                                ret = -EIO;
 294                        }
 295                }
 296        }
 297
 298        return ret;
 299}
 300
 301static void deallocate_channel(struct fw_card *card, int irm_id,
 302                               int generation, int channel)
 303{
 304        u32 mask;
 305        u64 offset;
 306
 307        mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 308        offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 309                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 310
 311        manage_channel(card, irm_id, generation, mask, offset, false);
 312}
 313
 314/**
 315 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
 316 * @card: card interface for this action
 317 * @generation: bus generation
 318 * @channels_mask: bitmask for channel allocation
 319 * @channel: pointer for returning channel allocation result
 320 * @bandwidth: pointer for returning bandwidth allocation result
 321 * @allocate: whether to allocate (true) or deallocate (false)
 322 *
 323 * In parameters: card, generation, channels_mask, bandwidth, allocate
 324 * Out parameters: channel, bandwidth
 325 *
 326 * This function blocks (sleeps) during communication with the IRM.
 327 *
 328 * Allocates or deallocates at most one channel out of channels_mask.
 329 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 330 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 331 * channel 0 and LSB for channel 63.)
 332 * Allocates or deallocates as many bandwidth allocation units as specified.
 333 *
 334 * Returns channel < 0 if no channel was allocated or deallocated.
 335 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 336 *
 337 * If generation is stale, deallocations succeed but allocations fail with
 338 * channel = -EAGAIN.
 339 *
 340 * If channel allocation fails, no bandwidth will be allocated either.
 341 * If bandwidth allocation fails, no channel will be allocated either.
 342 * But deallocations of channel and bandwidth are tried independently
 343 * of each other's success.
 344 */
 345void fw_iso_resource_manage(struct fw_card *card, int generation,
 346                            u64 channels_mask, int *channel, int *bandwidth,
 347                            bool allocate)
 348{
 349        u32 channels_hi = channels_mask;        /* channels 31...0 */
 350        u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 351        int irm_id, ret, c = -EINVAL;
 352
 353        spin_lock_irq(&card->lock);
 354        irm_id = card->irm_node->node_id;
 355        spin_unlock_irq(&card->lock);
 356
 357        if (channels_hi)
 358                c = manage_channel(card, irm_id, generation, channels_hi,
 359                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 360                                allocate);
 361        if (channels_lo && c < 0) {
 362                c = manage_channel(card, irm_id, generation, channels_lo,
 363                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 364                                allocate);
 365                if (c >= 0)
 366                        c += 32;
 367        }
 368        *channel = c;
 369
 370        if (allocate && channels_mask != 0 && c < 0)
 371                *bandwidth = 0;
 372
 373        if (*bandwidth == 0)
 374                return;
 375
 376        ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 377        if (ret < 0)
 378                *bandwidth = 0;
 379
 380        if (allocate && ret < 0) {
 381                if (c >= 0)
 382                        deallocate_channel(card, irm_id, generation, c);
 383                *channel = ret;
 384        }
 385}
 386EXPORT_SYMBOL(fw_iso_resource_manage);
 387