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_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_array(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
  67 int 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
  90 int 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 }
 105 EXPORT_SYMBOL(fw_iso_buffer_init);
 106
 107 int 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
 125 void 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 }
 144 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 145
 146 /* Convert DMA address to offset into virtually contiguous buffer. */
 147 size_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
 163 struct 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 }
 184 EXPORT_SYMBOL(fw_iso_context_create);
 185
 186 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 187 {
 188         ctx->card->driver->free_iso_context(ctx);
 189 }
 190 EXPORT_SYMBOL(fw_iso_context_destroy);
 191
 192 int 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 }
 197 EXPORT_SYMBOL(fw_iso_context_start);
 198
 199 int 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
 204 int 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 }
 211 EXPORT_SYMBOL(fw_iso_context_queue);
 212
 213 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 214 {
 215         ctx->card->driver->flush_queue_iso(ctx);
 216 }
 217 EXPORT_SYMBOL(fw_iso_context_queue_flush);
 218
 219 int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 220 {
 221         return ctx->card->driver->flush_iso_completions(ctx);
 222 }
 223 EXPORT_SYMBOL(fw_iso_context_flush_completions);
 224
 225 int fw_iso_context_stop(struct fw_iso_context *ctx)
 226 {
 227         return ctx->card->driver->stop_iso(ctx);
 228 }
 229 EXPORT_SYMBOL(fw_iso_context_stop);
 230
 231 /*
 232  * Isochronous bus resource management (channels, bandwidth), client side
 233  */
 234
 235 static 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
 273 static 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
 325 static 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  */
 362 void 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 }
 403 EXPORT_SYMBOL(fw_iso_resource_manage);