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         return vm_map_pages_zero(vma, buffer->pages,
 111                                         buffer->page_count);
 112 }
 113
 114 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 115                            struct fw_card *card)
 116 {
 117         int i;
 118         dma_addr_t address;
 119
 120         for (i = 0; i < buffer->page_count_mapped; i++) {
 121                 address = page_private(buffer->pages[i]);
 122                 dma_unmap_page(card->device, address,
 123                                PAGE_SIZE, buffer->direction);
 124         }
 125         for (i = 0; i < buffer->page_count; i++)
 126                 __free_page(buffer->pages[i]);
 127
 128         kfree(buffer->pages);
 129         buffer->pages = NULL;
 130         buffer->page_count = 0;
 131         buffer->page_count_mapped = 0;
 132 }
 133 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 134
 135 /* Convert DMA address to offset into virtually contiguous buffer. */
 136 size_t fw_iso_buffer_lookup(struct fw_iso_buffer *buffer, dma_addr_t completed)
 137 {
 138         size_t i;
 139         dma_addr_t address;
 140         ssize_t offset;
 141
 142         for (i = 0; i < buffer->page_count; i++) {
 143                 address = page_private(buffer->pages[i]);
 144                 offset = (ssize_t)completed - (ssize_t)address;
 145                 if (offset > 0 && offset <= PAGE_SIZE)
 146                         return (i << PAGE_SHIFT) + offset;
 147         }
 148
 149         return 0;
 150 }
 151
 152 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 153                 int type, int channel, int speed, size_t header_size,
 154                 fw_iso_callback_t callback, void *callback_data)
 155 {
 156         struct fw_iso_context *ctx;
 157
 158         ctx = card->driver->allocate_iso_context(card,
 159                                                  type, channel, header_size);
 160         if (IS_ERR(ctx))
 161                 return ctx;
 162
 163         ctx->card = card;
 164         ctx->type = type;
 165         ctx->channel = channel;
 166         ctx->speed = speed;
 167         ctx->header_size = header_size;
 168         ctx->callback.sc = callback;
 169         ctx->callback_data = callback_data;
 170
 171         return ctx;
 172 }
 173 EXPORT_SYMBOL(fw_iso_context_create);
 174
 175 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 176 {
 177         ctx->card->driver->free_iso_context(ctx);
 178 }
 179 EXPORT_SYMBOL(fw_iso_context_destroy);
 180
 181 int fw_iso_context_start(struct fw_iso_context *ctx,
 182                          int cycle, int sync, int tags)
 183 {
 184         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 185 }
 186 EXPORT_SYMBOL(fw_iso_context_start);
 187
 188 int fw_iso_context_set_channels(struct fw_iso_context *ctx, u64 *channels)
 189 {
 190         return ctx->card->driver->set_iso_channels(ctx, channels);
 191 }
 192
 193 int fw_iso_context_queue(struct fw_iso_context *ctx,
 194                          struct fw_iso_packet *packet,
 195                          struct fw_iso_buffer *buffer,
 196                          unsigned long payload)
 197 {
 198         return ctx->card->driver->queue_iso(ctx, packet, buffer, payload);
 199 }
 200 EXPORT_SYMBOL(fw_iso_context_queue);
 201
 202 void fw_iso_context_queue_flush(struct fw_iso_context *ctx)
 203 {
 204         ctx->card->driver->flush_queue_iso(ctx);
 205 }
 206 EXPORT_SYMBOL(fw_iso_context_queue_flush);
 207
 208 int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 209 {
 210         return ctx->card->driver->flush_iso_completions(ctx);
 211 }
 212 EXPORT_SYMBOL(fw_iso_context_flush_completions);
 213
 214 int fw_iso_context_stop(struct fw_iso_context *ctx)
 215 {
 216         return ctx->card->driver->stop_iso(ctx);
 217 }
 218 EXPORT_SYMBOL(fw_iso_context_stop);
 219
 220 /*
 221  * Isochronous bus resource management (channels, bandwidth), client side
 222  */
 223
 224 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 225                             int bandwidth, bool allocate)
 226 {
 227         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 228         __be32 data[2];
 229
 230         /*
 231          * On a 1394a IRM with low contention, try < 1 is enough.
 232          * On a 1394-1995 IRM, we need at least try < 2.
 233          * Let's just do try < 5.
 234          */
 235         for (try = 0; try < 5; try++) {
 236                 new = allocate ? old - bandwidth : old + bandwidth;
 237                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 238                         return -EBUSY;
 239
 240                 data[0] = cpu_to_be32(old);
 241                 data[1] = cpu_to_be32(new);
 242                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 243                                 irm_id, generation, SCODE_100,
 244                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 245                                 data, 8)) {
 246                 case RCODE_GENERATION:
 247                         /* A generation change frees all bandwidth. */
 248                         return allocate ? -EAGAIN : bandwidth;
 249
 250                 case RCODE_COMPLETE:
 251                         if (be32_to_cpup(data) == old)
 252                                 return bandwidth;
 253
 254                         old = be32_to_cpup(data);
 255                         /* Fall through. */
 256                 }
 257         }
 258
 259         return -EIO;
 260 }
 261
 262 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 263                 u32 channels_mask, u64 offset, bool allocate)
 264 {
 265         __be32 bit, all, old;
 266         __be32 data[2];
 267         int channel, ret = -EIO, retry = 5;
 268
 269         old = all = allocate ? cpu_to_be32(~0) : 0;
 270
 271         for (channel = 0; channel < 32; channel++) {
 272                 if (!(channels_mask & 1 << channel))
 273                         continue;
 274
 275                 ret = -EBUSY;
 276
 277                 bit = cpu_to_be32(1 << (31 - channel));
 278                 if ((old & bit) != (all & bit))
 279                         continue;
 280
 281                 data[0] = old;
 282                 data[1] = old ^ bit;
 283                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 284                                            irm_id, generation, SCODE_100,
 285                                            offset, data, 8)) {
 286                 case RCODE_GENERATION:
 287                         /* A generation change frees all channels. */
 288                         return allocate ? -EAGAIN : channel;
 289
 290                 case RCODE_COMPLETE:
 291                         if (data[0] == old)
 292                                 return channel;
 293
 294                         old = data[0];
 295
 296                         /* Is the IRM 1394a-2000 compliant? */
 297                         if ((data[0] & bit) == (data[1] & bit))
 298                                 continue;
 299
 300                         /* 1394-1995 IRM, fall through to retry. */
 301                 default:
 302                         if (retry) {
 303                                 retry--;
 304                                 channel--;
 305                         } else {
 306                                 ret = -EIO;
 307                         }
 308                 }
 309         }
 310
 311         return ret;
 312 }
 313
 314 static void deallocate_channel(struct fw_card *card, int irm_id,
 315                                int generation, int channel)
 316 {
 317         u32 mask;
 318         u64 offset;
 319
 320         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 321         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 322                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 323
 324         manage_channel(card, irm_id, generation, mask, offset, false);
 325 }
 326
 327 /**
 328  * fw_iso_resource_manage() - Allocate or deallocate a channel and/or bandwidth
 329  * @card: card interface for this action
 330  * @generation: bus generation
 331  * @channels_mask: bitmask for channel allocation
 332  * @channel: pointer for returning channel allocation result
 333  * @bandwidth: pointer for returning bandwidth allocation result
 334  * @allocate: whether to allocate (true) or deallocate (false)
 335  *
 336  * In parameters: card, generation, channels_mask, bandwidth, allocate
 337  * Out parameters: channel, bandwidth
 338  *
 339  * This function blocks (sleeps) during communication with the IRM.
 340  *
 341  * Allocates or deallocates at most one channel out of channels_mask.
 342  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 343  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 344  * channel 0 and LSB for channel 63.)
 345  * Allocates or deallocates as many bandwidth allocation units as specified.
 346  *
 347  * Returns channel < 0 if no channel was allocated or deallocated.
 348  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 349  *
 350  * If generation is stale, deallocations succeed but allocations fail with
 351  * channel = -EAGAIN.
 352  *
 353  * If channel allocation fails, no bandwidth will be allocated either.
 354  * If bandwidth allocation fails, no channel will be allocated either.
 355  * But deallocations of channel and bandwidth are tried independently
 356  * of each other's success.
 357  */
 358 void fw_iso_resource_manage(struct fw_card *card, int generation,
 359                             u64 channels_mask, int *channel, int *bandwidth,
 360                             bool allocate)
 361 {
 362         u32 channels_hi = channels_mask;        /* channels 31...0 */
 363         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 364         int irm_id, ret, c = -EINVAL;
 365
 366         spin_lock_irq(&card->lock);
 367         irm_id = card->irm_node->node_id;
 368         spin_unlock_irq(&card->lock);
 369
 370         if (channels_hi)
 371                 c = manage_channel(card, irm_id, generation, channels_hi,
 372                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI,
 373                                 allocate);
 374         if (channels_lo && c < 0) {
 375                 c = manage_channel(card, irm_id, generation, channels_lo,
 376                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO,
 377                                 allocate);
 378                 if (c >= 0)
 379                         c += 32;
 380         }
 381         *channel = c;
 382
 383         if (allocate && channels_mask != 0 && c < 0)
 384                 *bandwidth = 0;
 385
 386         if (*bandwidth == 0)
 387                 return;
 388
 389         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 390         if (ret < 0)
 391                 *bandwidth = 0;
 392
 393         if (allocate && ret < 0) {
 394                 if (c >= 0)
 395                         deallocate_channel(card, irm_id, generation, c);
 396                 *channel = ret;
 397         }
 398 }
 399 EXPORT_SYMBOL(fw_iso_resource_manage);