drivers/firewire/fw-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-constants.h>
  26 #include <linux/kernel.h>
  27 #include <linux/mm.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/vmalloc.h>
  30
  31 #include "fw-topology.h"
  32 #include "fw-transaction.h"
  33
  34 /*
  35  * Isochronous DMA context management
  36  */
  37
  38 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  39                        int page_count, enum dma_data_direction direction)
  40 {
  41         int i, j;
  42         dma_addr_t address;
  43
  44         buffer->page_count = page_count;
  45         buffer->direction = direction;
  46
  47         buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
  48                                 GFP_KERNEL);
  49         if (buffer->pages == NULL)
  50                 goto out;
  51
  52         for (i = 0; i < buffer->page_count; i++) {
  53                 buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  54                 if (buffer->pages[i] == NULL)
  55                         goto out_pages;
  56
  57                 address = dma_map_page(card->device, buffer->pages[i],
  58                                        0, PAGE_SIZE, direction);
  59                 if (dma_mapping_error(card->device, address)) {
  60                         __free_page(buffer->pages[i]);
  61                         goto out_pages;
  62                 }
  63                 set_page_private(buffer->pages[i], address);
  64         }
  65
  66         return 0;
  67
  68  out_pages:
  69         for (j = 0; j < i; j++) {
  70                 address = page_private(buffer->pages[j]);
  71                 dma_unmap_page(card->device, address,
  72                                PAGE_SIZE, DMA_TO_DEVICE);
  73                 __free_page(buffer->pages[j]);
  74         }
  75         kfree(buffer->pages);
  76  out:
  77         buffer->pages = NULL;
  78
  79         return -ENOMEM;
  80 }
  81
  82 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
  83 {
  84         unsigned long uaddr;
  85         int i, err;
  86
  87         uaddr = vma->vm_start;
  88         for (i = 0; i < buffer->page_count; i++) {
  89                 err = vm_insert_page(vma, uaddr, buffer->pages[i]);
  90                 if (err)
  91                         return err;
  92
  93                 uaddr += PAGE_SIZE;
  94         }
  95
  96         return 0;
  97 }
  98
  99 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 100                            struct fw_card *card)
 101 {
 102         int i;
 103         dma_addr_t address;
 104
 105         for (i = 0; i < buffer->page_count; i++) {
 106                 address = page_private(buffer->pages[i]);
 107                 dma_unmap_page(card->device, address,
 108                                PAGE_SIZE, DMA_TO_DEVICE);
 109                 __free_page(buffer->pages[i]);
 110         }
 111
 112         kfree(buffer->pages);
 113         buffer->pages = NULL;
 114 }
 115
 116 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 117                 int type, int channel, int speed, size_t header_size,
 118                 fw_iso_callback_t callback, void *callback_data)
 119 {
 120         struct fw_iso_context *ctx;
 121
 122         ctx = card->driver->allocate_iso_context(card,
 123                                                  type, channel, header_size);
 124         if (IS_ERR(ctx))
 125                 return ctx;
 126
 127         ctx->card = card;
 128         ctx->type = type;
 129         ctx->channel = channel;
 130         ctx->speed = speed;
 131         ctx->header_size = header_size;
 132         ctx->callback = callback;
 133         ctx->callback_data = callback_data;
 134
 135         return ctx;
 136 }
 137
 138 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 139 {
 140         struct fw_card *card = ctx->card;
 141
 142         card->driver->free_iso_context(ctx);
 143 }
 144
 145 int fw_iso_context_start(struct fw_iso_context *ctx,
 146                          int cycle, int sync, int tags)
 147 {
 148         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 149 }
 150
 151 int fw_iso_context_queue(struct fw_iso_context *ctx,
 152                          struct fw_iso_packet *packet,
 153                          struct fw_iso_buffer *buffer,
 154                          unsigned long payload)
 155 {
 156         struct fw_card *card = ctx->card;
 157
 158         return card->driver->queue_iso(ctx, packet, buffer, payload);
 159 }
 160
 161 int fw_iso_context_stop(struct fw_iso_context *ctx)
 162 {
 163         return ctx->card->driver->stop_iso(ctx);
 164 }
 165
 166 /*
 167  * Isochronous bus resource management (channels, bandwidth), client side
 168  */
 169
 170 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 171                             int bandwidth, bool allocate)
 172 {
 173         __be32 data[2];
 174         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 175
 176         /*
 177          * On a 1394a IRM with low contention, try < 1 is enough.
 178          * On a 1394-1995 IRM, we need at least try < 2.
 179          * Let's just do try < 5.
 180          */
 181         for (try = 0; try < 5; try++) {
 182                 new = allocate ? old - bandwidth : old + bandwidth;
 183                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 184                         break;
 185
 186                 data[0] = cpu_to_be32(old);
 187                 data[1] = cpu_to_be32(new);
 188                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 189                                 irm_id, generation, SCODE_100,
 190                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 191                                 data, sizeof(data))) {
 192                 case RCODE_GENERATION:
 193                         /* A generation change frees all bandwidth. */
 194                         return allocate ? -EAGAIN : bandwidth;
 195
 196                 case RCODE_COMPLETE:
 197                         if (be32_to_cpup(data) == old)
 198                                 return bandwidth;
 199
 200                         old = be32_to_cpup(data);
 201                         /* Fall through. */
 202                 }
 203         }
 204
 205         return -EIO;
 206 }
 207
 208 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 209                           u32 channels_mask, u64 offset, bool allocate)
 210 {
 211         __be32 data[2], c, all, old;
 212         int i, retry = 5;
 213
 214         old = all = allocate ? cpu_to_be32(~0) : 0;
 215
 216         for (i = 0; i < 32; i++) {
 217                 if (!(channels_mask & 1 << i))
 218                         continue;
 219
 220                 c = cpu_to_be32(1 << (31 - i));
 221                 if ((old & c) != (all & c))
 222                         continue;
 223
 224                 data[0] = old;
 225                 data[1] = old ^ c;
 226                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 227                                            irm_id, generation, SCODE_100,
 228                                            offset, data, sizeof(data))) {
 229                 case RCODE_GENERATION:
 230                         /* A generation change frees all channels. */
 231                         return allocate ? -EAGAIN : i;
 232
 233                 case RCODE_COMPLETE:
 234                         if (data[0] == old)
 235                                 return i;
 236
 237                         old = data[0];
 238
 239                         /* Is the IRM 1394a-2000 compliant? */
 240                         if ((data[0] & c) == (data[1] & c))
 241                                 continue;
 242
 243                         /* 1394-1995 IRM, fall through to retry. */
 244                 default:
 245                         if (retry--)
 246                                 i--;
 247                 }
 248         }
 249
 250         return -EIO;
 251 }
 252
 253 static void deallocate_channel(struct fw_card *card, int irm_id,
 254                                int generation, int channel)
 255 {
 256         u32 mask;
 257         u64 offset;
 258
 259         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 260         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 261                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 262
 263         manage_channel(card, irm_id, generation, mask, offset, false);
 264 }
 265
 266 /**
 267  * fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
 268  *
 269  * In parameters: card, generation, channels_mask, bandwidth, allocate
 270  * Out parameters: channel, bandwidth
 271  * This function blocks (sleeps) during communication with the IRM.
 272  *
 273  * Allocates or deallocates at most one channel out of channels_mask.
 274  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 275  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 276  * channel 0 and LSB for channel 63.)
 277  * Allocates or deallocates as many bandwidth allocation units as specified.
 278  *
 279  * Returns channel < 0 if no channel was allocated or deallocated.
 280  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 281  *
 282  * If generation is stale, deallocations succeed but allocations fail with
 283  * channel = -EAGAIN.
 284  *
 285  * If channel allocation fails, no bandwidth will be allocated either.
 286  * If bandwidth allocation fails, no channel will be allocated either.
 287  * But deallocations of channel and bandwidth are tried independently
 288  * of each other's success.
 289  */
 290 void fw_iso_resource_manage(struct fw_card *card, int generation,
 291                             u64 channels_mask, int *channel, int *bandwidth,
 292                             bool allocate)
 293 {
 294         u32 channels_hi = channels_mask;        /* channels 31...0 */
 295         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 296         int irm_id, ret, c = -EINVAL;
 297
 298         spin_lock_irq(&card->lock);
 299         irm_id = card->irm_node->node_id;
 300         spin_unlock_irq(&card->lock);
 301
 302         if (channels_hi)
 303                 c = manage_channel(card, irm_id, generation, channels_hi,
 304                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
 305         if (channels_lo && c < 0) {
 306                 c = manage_channel(card, irm_id, generation, channels_lo,
 307                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
 308                 if (c >= 0)
 309                         c += 32;
 310         }
 311         *channel = c;
 312
 313         if (allocate && channels_mask != 0 && c < 0)
 314                 *bandwidth = 0;
 315
 316         if (*bandwidth == 0)
 317                 return;
 318
 319         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 320         if (ret < 0)
 321                 *bandwidth = 0;
 322
 323         if (allocate && ret < 0 && c >= 0) {
 324                 deallocate_channel(card, irm_id, generation, c);
 325                 *channel = ret;
 326         }
 327 }