linux/drivers/firewire/core-iso.c
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   1/*
   2 * Isochronous I/O functionality:
   3 *   - Isochronous DMA context management
   4 *   - Isochronous bus resource management (channels, bandwidth), client side
   5 *
   6 * Copyright (C) 2006 Kristian Hoegsberg <krh@bitplanet.net>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software Foundation,
  20 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21 */
  22
  23#include <linux/dma-mapping.h>
  24#include <linux/errno.h>
  25#include <linux/firewire.h>
  26#include <linux/firewire-constants.h>
  27#include <linux/kernel.h>
  28#include <linux/mm.h>
  29#include <linux/slab.h>
  30#include <linux/spinlock.h>
  31#include <linux/vmalloc.h>
  32#include <linux/export.h>
  33
  34#include <asm/byteorder.h>
  35
  36#include "core.h"
  37
  38/*
  39 * Isochronous DMA context management
  40 */
  41
  42int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
  43{
  44        int i;
  45
  46        buffer->page_count = 0;
  47        buffer->page_count_mapped = 0;
  48        buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
  49                                GFP_KERNEL);
  50        if (buffer->pages == NULL)
  51                return -ENOMEM;
  52
  53        for (i = 0; i < page_count; i++) {
  54                buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  55                if (buffer->pages[i] == NULL)
  56                        break;
  57        }
  58        buffer->page_count = i;
  59        if (i < page_count) {
  60                fw_iso_buffer_destroy(buffer, NULL);
  61                return -ENOMEM;
  62        }
  63
  64        return 0;
  65}
  66
  67int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
  68                          enum dma_data_direction direction)
  69{
  70        dma_addr_t address;
  71        int i;
  72
  73        buffer->direction = direction;
  74
  75        for (i = 0; i < buffer->page_count; i++) {
  76                address = dma_map_page(card->device, buffer->pages[i],
  77                                       0, PAGE_SIZE, direction);
  78                if (dma_mapping_error(card->device, address))
  79                        break;
  80
  81                set_page_private(buffer->pages[i], address);
  82        }
  83        buffer->page_count_mapped = i;
  84        if (i < buffer->page_count)
  85                return -ENOMEM;
  86
  87        return 0;
  88}
  89
  90int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  91                       int page_count, enum dma_data_direction direction)
  92{
  93        int ret;
  94
  95        ret = fw_iso_buffer_alloc(buffer, page_count);
  96        if (ret < 0)
  97                return ret;
  98
  99        ret = fw_iso_buffer_map_dma(buffer, card, direction);
 100        if (ret < 0)
 101                fw_iso_buffer_destroy(buffer, card);
 102
 103        return ret;
 104}
 105EXPORT_SYMBOL(fw_iso_buffer_init);
 106
 107int fw_iso_buffer_map_vma(struct fw_iso_buffer *buffer,
 108                          struct vm_area_struct *vma)
 109{
 110        unsigned long uaddr;
 111        int i, err;
 112
 113        uaddr = vma->vm_start;
 114        for (i = 0; i < buffer->page_count; i++) {
 115                err = vm_insert_page(vma, uaddr, buffer->pages[i]);
 116                if (err)
 117                        return err;
 118
 119                uaddr += PAGE_SIZE;
 120        }
 121
 122        return 0;
 123}
 124
 125void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 126                           struct fw_card *card)
 127{
 128        int i;
 129        dma_addr_t address;
 130
 131        for (i = 0; i < buffer->page_count_mapped; i++) {
 132                address = page_private(buffer->pages[i]);
 133                dma_unmap_page(card->device, address,
 134                               PAGE_SIZE, buffer->direction);
 135        }
 136        for (i = 0; i < buffer->page_count; i++)
 137                __free_page(buffer->pages[i]);
 138
 139        kfree(buffer->pages);
 140        buffer->pages = NULL;
 141        buffer->page_count = 0;
 142        buffer->page_count_mapped = 0;
 143}
 144EXPORT_SYMBOL(fw_iso_buffer_destroy);
 145
 146/* Convert DMA address to offset into virtually contiguous buffer. */
 147size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 148{
 149        size_t i;
 150        dma_addr_t address;
 151        ssize_t offset;
 152
 153        for (i = 0; i < buffer->page_count; i++) {
 154                address = page_private(buffer->pages[i]);
 155                offset = (ssize_t)completed - (ssize_t)address;
 156                if (offset > 0 && offset <= PAGE_SIZE)
 157                        return (i << PAGE_SHIFT) + offset;
 158        }
 159
 160        return 0;
 161}
 162
 163struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 164                int type, int channel, int speed, size_t header_size,
 165                fw_iso_callback_t callback, void *callback_data)
 166{
 167        struct fw_iso_context *ctx;
 168
 169        ctx = card->driver->allocate_iso_context(card,
 170                                                 type, channel, header_size);
 171        if (IS_ERR(ctx))
 172                return ctx;
 173
 174        ctx->card = card;
 175        ctx->type = type;
 176        ctx->channel = channel;
 177        ctx->speed = speed;
 178        ctx->header_size = header_size;
 179        ctx->callback.sc = callback;
 180        ctx->callback_data = callback_data;
 181
 182        return ctx;
 183}
 184EXPORT_SYMBOL(fw_iso_context_create);
 185
 186void fw_iso_context_destroy(struct fw_iso_context *ctx)
 187{
 188        ctx->card->driver->free_iso_context(ctx);
 189}
 190EXPORT_SYMBOL(fw_iso_context_destroy);
 191
 192int fw_iso_context_start(struct fw_iso_context *ctx,
 193                         int cycle, int sync, int tags)
 194{
 195        return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 196}
 197EXPORT_SYMBOL(fw_iso_context_start);
 198
 199int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
 200{
 201        return ctx->card->driver->set_iso_channels(ctx, channels);
 202}
 203
 204int fw_iso_context_queue(struct fw_iso_context *ctx,
 205                         struct fw_iso_packet *packet,
 206                         struct fw_iso_buffer *buffer,
 207                         unsigned long payload)
 208{
 209        return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
 210}
 211EXPORT_SYMBOL(fw_iso_context_queue);
 212
 213void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 214{
 215        ctx->card->driver->flush_queue_iso(ctx);
 216}
 217EXPORT_SYMBOL(fw_iso_context_queue_flush);
 218
 219int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 220{
 221        return ctx->card->driver->flush_iso_completions(ctx);
 222}
 223EXPORT_SYMBOL(fw_iso_context_flush_completions);
 224
 225int fw_iso_context_stop(struct fw_iso_context *ctx)
 226{
 227        return ctx->card->driver->stop_iso(ctx);
 228}
 229EXPORT_SYMBOL(fw_iso_context_stop);
 230
 231/*
 232 * Isochronous bus resource management (channels, bandwidth), client side
 233 */
 234
 235static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 236                            int bandwidth, bool allocate)
 237{
 238        int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 239        __be32 data[2];
 240
 241        /*
 242         * On a 1394a IRM with low contention, try < 1 is enough.
 243         * On a 1394-1995 IRM, we need at least try < 2.
 244         * Let's just do try < 5.
 245         */
 246        for (try = 0; try < 5; try++) {
 247                new = allocate ? old - bandwidth : old + bandwidth;
 248                if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 249                        return -EBUSY;
 250
 251                data[0] = cpu_to_be32(old);
 252                data[1] = cpu_to_be32(new);
 253                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 254                                irm_id, generation, SCODE_100,
 255                                CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 256                                data, 8)) {
 257                case RCODE_GENERATION:
 258                        /* A generation change frees all bandwidth. */
 259                        return allocate ? -EAGAIN : bandwidth;
 260
 261                case RCODE_COMPLETE:
 262                        if (be32_to_cpup(data) == old)
 263                                return bandwidth;
 264
 265                        old = be32_to_cpup(data);
 266                        /* Fall through. */
 267                }
 268        }
 269
 270        return -EIO;
 271}
 272
 273static int manage_channel(struct fw_card *card, int irm_id, int generation,
 274                u32 channels_mask, u64 offset, bool allocate)
 275{
 276        __be32 bit, all, old;
 277        __be32 data[2];
 278        int channel, ret = -EIO, retry = 5;
 279
 280        old = all = allocate ? cpu_to_be32(~0) : 0;
 281
 282        for (channel = 0; channel < 32; channel++) {
 283                if (!(channels_mask & 1 << channel))
 284                        continue;
 285
 286                ret = -EBUSY;
 287
 288                bit = cpu_to_be32(1 << (31 - channel));
 289                if ((old & bit) != (all & bit))
 290                        continue;
 291
 292                data[0] = old;
 293                data[1] = old ^ bit;
 294                switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 295                                           irm_id, generation, SCODE_100,
 296                                           offset, data, 8)) {
 297                case RCODE_GENERATION:
 298                        /* A generation change frees all channels. */
 299                        return allocate ? -EAGAIN : channel;
 300
 301                case RCODE_COMPLETE:
 302                        if (data[0] == old)
 303                                return channel;
 304
 305                        old = data[0];
 306
 307                        /* Is the IRM 1394a-2000 compliant? */
 308                        if ((data[0] & bit) == (data[1] & bit))
 309                                continue;
 310
 311                        /* 1394-1995 IRM, fall through to retry. */
 312                default:
 313                        if (retry) {
 314                                retry--;
 315                                channel--;
 316                        } else {
 317                                ret = -EIO;
 318                        }
 319                }
 320        }
 321
 322        return ret;
 323}
 324
 325static void deallocate_channel(struct fw_card *card, int irm_id,
 326                               int generation, int channel)
 327{
 328        u32 mask;
 329        u64 offset;
 330
 331        mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 332        offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 333                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 334
 335        manage_channel(card, irm_id, generation, mask, offset, false);
 336}
 337
 338/**
 339 * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
 340 *
 341 * In parameters: card, generation, channels_mask, bandwidth, allocate
 342 * Out parameters: channel, bandwidth
 343 * This function blocks (sleeps) during communication with the IRM.
 344 *
 345 * Allocates or deallocates at most one channel out of channels_mask.
 346 * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 347 * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 348 * channel 0 and LSB for channel 63.)
 349 * Allocates or deallocates as many bandwidth allocation units as specified.
 350 *
 351 * Returns channel < 0 if no channel was allocated or deallocated.
 352 * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 353 *
 354 * If generation is stale, deallocations succeed but allocations fail with
 355 * channel = -EAGAIN.
 356 *
 357 * If channel allocation fails, no bandwidth will be allocated either.
 358 * If bandwidth allocation fails, no channel will be allocated either.
 359 * But deallocations of channel and bandwidth are tried independently
 360 * of each other's success.
 361 */
 362void fw_iso_resource_manage(struct fw_card *card, int generation,
 363                            u64 channels_mask, int *channel, int *bandwidth,
 364                            bool allocate)
 365{
 366        u32 channels_hi = channels_mask;        /* channels 31...0 */
 367        u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 368        int irm_id, ret, c = -EINVAL;
 369
 370        spin_lock_irq(&card->lock);
 371        irm_id = card->irm_node->node_id;
 372        spin_unlock_irq(&card->lock);
 373
 374        if (channels_hi)
 375                c = manage_channel(card, irm_id, generation, channels_hi,
 376                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 377                                allocate);
 378        if (channels_lo && c < 0) {
 379                c = manage_channel(card, irm_id, generation, channels_lo,
 380                                CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 381                                allocate);
 382                if (c >= 0)
 383                        c += 32;
 384        }
 385        *channel = c;
 386
 387        if (allocate && channels_mask != 0 && c < 0)
 388                *bandwidth = 0;
 389
 390        if (*bandwidth == 0)
 391                return;
 392
 393        ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 394        if (ret < 0)
 395                *bandwidth = 0;
 396
 397        if (allocate && ret < 0) {
 398                if (c >= 0)
 399                        deallocate_channel(card, irm_id, generation, c);
 400                *channel = ret;
 401        }
 402}
 403EXPORT_SYMBOL(fw_iso_resource_manage);
 404
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