drivers/firewire/core-iso.c

   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
  42 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  43                        int page_count, enum dma_data_direction direction)
  44 {
  45         int i, j;
  46         dma_addr_t address;
  47
  48         buffer->page_count = page_count;
  49         buffer->direction = direction;
  50
  51         buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
  52                                 GFP_KERNEL);
  53         if (buffer->pages == NULL)
  54                 goto out;
  55
  56         for (i = 0; i < buffer->page_count; i++) {
  57                 buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  58                 if (buffer->pages[i] == NULL)
  59                         goto out_pages;
  60
  61                 address = dma_map_page(card->device, buffer->pages[i],
  62                                        0, PAGE_SIZE, direction);
  63                 if (dma_mapping_error(card->device, address)) {
  64                         __free_page(buffer->pages[i]);
  65                         goto out_pages;
  66                 }
  67                 set_page_private(buffer->pages[i], address);
  68         }
  69
  70         return 0;
  71
  72  out_pages:
  73         for (j = 0; j < i; j++) {
  74                 address = page_private(buffer->pages[j]);
  75                 dma_unmap_page(card->device, address,
  76                                PAGE_SIZE, direction);
  77                 __free_page(buffer->pages[j]);
  78         }
  79         kfree(buffer->pages);
  80  out:
  81         buffer->pages = NULL;
  82
  83         return -ENOMEM;
  84 }
  85 EXPORT_SYMBOL(fw_iso_buffer_init);
  86
  87 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
  88 {
  89         unsigned long uaddr;
  90         int i, err;
  91
  92         uaddr = vma->vm_start;
  93         for (i = 0; i < buffer->page_count; i++) {
  94                 err = vm_insert_page(vma, uaddr, buffer->pages[i]);
  95                 if (err)
  96                         return err;
  97
  98                 uaddr += PAGE_SIZE;
  99         }
 100
 101         return 0;
 102 }
 103
 104 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 105                            struct fw_card *card)
 106 {
 107         int i;
 108         dma_addr_t address;
 109
 110         for (i = 0; i < buffer->page_count; i++) {
 111                 address = page_private(buffer->pages[i]);
 112                 dma_unmap_page(card->device, address,
 113                                PAGE_SIZE, buffer->direction);
 114                 __free_page(buffer->pages[i]);
 115         }
 116
 117         kfree(buffer->pages);
 118         buffer->pages = NULL;
 119 }
 120 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 121
 122 /* Convert DMA address to offset into virtually contiguous buffer. */
 123 size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 124 {
 125         int 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
 139 struct 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 }
 160 EXPORT_SYMBOL(fw_iso_context_create);
 161
 162 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 163 {
 164         ctx->card->driver->free_iso_context(ctx);
 165 }
 166 EXPORT_SYMBOL(fw_iso_context_destroy);
 167
 168 int 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 }
 173 EXPORT_SYMBOL(fw_iso_context_start);
 174
 175 int 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
 180 int 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 }
 187 EXPORT_SYMBOL(fw_iso_context_queue);
 188
 189 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 190 {
 191         ctx->card->driver->flush_queue_iso(ctx);
 192 }
 193 EXPORT_SYMBOL(fw_iso_context_queue_flush);
 194
 195 int fw_iso_context_stop(struct fw_iso_context *ctx)
 196 {
 197         return ctx->card->driver->stop_iso(ctx);
 198 }
 199 EXPORT_SYMBOL(fw_iso_context_stop);
 200
 201 /*
 202  * Isochronous bus resource management (channels, bandwidth), client side
 203  */
 204
 205 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 206                             int bandwidth, bool allocate)
 207 {
 208         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 209         __be32 data[2];
 210
 211         /*
 212          * On a 1394a IRM with low contention, try < 1 is enough.
 213          * On a 1394-1995 IRM, we need at least try < 2.
 214          * Let's just do try < 5.
 215          */
 216         for (try = 0; try < 5; try++) {
 217                 new = allocate ? old - bandwidth : old + bandwidth;
 218                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 219                         return -EBUSY;
 220
 221                 data[0] = cpu_to_be32(old);
 222                 data[1] = cpu_to_be32(new);
 223                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 224                                 irm_id, generation, SCODE_100,
 225                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 226                                 data, 8)) {
 227                 case RCODE_GENERATION:
 228                         /* A generation change frees all bandwidth. */
 229                         return allocate ? -EAGAIN : bandwidth;
 230
 231                 case RCODE_COMPLETE:
 232                         if (be32_to_cpup(data) == old)
 233                                 return bandwidth;
 234
 235                         old = be32_to_cpup(data);
 236                         /* Fall through. */
 237                 }
 238         }
 239
 240         return -EIO;
 241 }
 242
 243 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 244                 u32 channels_mask, u64 offset, bool allocate)
 245 {
 246         __be32 bit, all, old;
 247         __be32 data[2];
 248         int channel, ret = -EIO, retry = 5;
 249
 250         old = all = allocate ? cpu_to_be32(~0) : 0;
 251
 252         for (channel = 0; channel < 32; channel++) {
 253                 if (!(channels_mask & 1 << channel))
 254                         continue;
 255
 256                 ret = -EBUSY;
 257
 258                 bit = cpu_to_be32(1 << (31 - channel));
 259                 if ((old & bit) != (all & bit))
 260                         continue;
 261
 262                 data[0] = old;
 263                 data[1] = old ^ bit;
 264                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 265                                            irm_id, generation, SCODE_100,
 266                                            offset, data, 8)) {
 267                 case RCODE_GENERATION:
 268                         /* A generation change frees all channels. */
 269                         return allocate ? -EAGAIN : channel;
 270
 271                 case RCODE_COMPLETE:
 272                         if (data[0] == old)
 273                                 return channel;
 274
 275                         old = data[0];
 276
 277                         /* Is the IRM 1394a-2000 compliant? */
 278                         if ((data[0] & bit) == (data[1] & bit))
 279                                 continue;
 280
 281                         /* 1394-1995 IRM, fall through to retry. */
 282                 default:
 283                         if (retry) {
 284                                 retry--;
 285                                 channel--;
 286                         } else {
 287                                 ret = -EIO;
 288                         }
 289                 }
 290         }
 291
 292         return ret;
 293 }
 294
 295 static void deallocate_channel(struct fw_card *card, int irm_id,
 296                                int generation, int channel)
 297 {
 298         u32 mask;
 299         u64 offset;
 300
 301         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 302         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 303                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 304
 305         manage_channel(card, irm_id, generation, mask, offset, false);
 306 }
 307
 308 /**
 309  * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
 310  *
 311  * In parameters: card, generation, channels_mask, bandwidth, allocate
 312  * Out parameters: channel, bandwidth
 313  * This function blocks (sleeps) during communication with the IRM.
 314  *
 315  * Allocates or deallocates at most one channel out of channels_mask.
 316  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 317  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 318  * channel 0 and LSB for channel 63.)
 319  * Allocates or deallocates as many bandwidth allocation units as specified.
 320  *
 321  * Returns channel < 0 if no channel was allocated or deallocated.
 322  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 323  *
 324  * If generation is stale, deallocations succeed but allocations fail with
 325  * channel = -EAGAIN.
 326  *
 327  * If channel allocation fails, no bandwidth will be allocated either.
 328  * If bandwidth allocation fails, no channel will be allocated either.
 329  * But deallocations of channel and bandwidth are tried independently
 330  * of each other's success.
 331  */
 332 void fw_iso_resource_manage(struct fw_card *card, int generation,
 333                             u64 channels_mask, int *channel, int *bandwidth,
 334                             bool allocate)
 335 {
 336         u32 channels_hi = channels_mask;        /* channels 31...0 */
 337         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 338         int irm_id, ret, c = -EINVAL;
 339
 340         spin_lock_irq(&card->lock);
 341         irm_id = card->irm_node->node_id;
 342         spin_unlock_irq(&card->lock);
 343
 344         if (channels_hi)
 345                 c = manage_channel(card, irm_id, generation, channels_hi,
 346                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 347                                 allocate);
 348         if (channels_lo && c < 0) {
 349                 c = manage_channel(card, irm_id, generation, channels_lo,
 350                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 351                                 allocate);
 352                 if (c >= 0)
 353                         c += 32;
 354         }
 355         *channel = c;
 356
 357         if (allocate && channels_mask != 0 && c < 0)
 358                 *bandwidth = 0;
 359
 360         if (*bandwidth == 0)
 361                 return;
 362
 363         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 364         if (ret < 0)
 365                 *bandwidth = 0;
 366
 367         if (allocate && ret < 0) {
 368                 if (c >= 0)
 369                         deallocate_channel(card, irm_id, generation, c);
 370                 *channel = ret;
 371         }
 372 }
 373 EXPORT_SYMBOL(fw_iso_resource_manage);