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         return -ENOMEM;
  79 }
  80
  81 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
  82 {
  83         unsigned long uaddr;
  84         int i, ret;
  85
  86         uaddr = vma->vm_start;
  87         for (i = 0; i < buffer->page_count; i++) {
  88                 ret = vm_insert_page(vma, uaddr, buffer->pages[i]);
  89                 if (ret)
  90                         return ret;
  91                 uaddr += PAGE_SIZE;
  92         }
  93
  94         return 0;
  95 }
  96
  97 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
  98                            struct fw_card *card)
  99 {
 100         int i;
 101         dma_addr_t address;
 102
 103         for (i = 0; i < buffer->page_count; i++) {
 104                 address = page_private(buffer->pages[i]);
 105                 dma_unmap_page(card->device, address,
 106                                PAGE_SIZE, DMA_TO_DEVICE);
 107                 __free_page(buffer->pages[i]);
 108         }
 109
 110         kfree(buffer->pages);
 111         buffer->pages = NULL;
 112 }
 113
 114 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 115                 int type, int channel, int speed, size_t header_size,
 116                 fw_iso_callback_t callback, void *callback_data)
 117 {
 118         struct fw_iso_context *ctx;
 119
 120         ctx = card->driver->allocate_iso_context(card,
 121                                                  type, channel, header_size);
 122         if (IS_ERR(ctx))
 123                 return ctx;
 124
 125         ctx->card = card;
 126         ctx->type = type;
 127         ctx->channel = channel;
 128         ctx->speed = speed;
 129         ctx->header_size = header_size;
 130         ctx->callback = callback;
 131         ctx->callback_data = callback_data;
 132
 133         return ctx;
 134 }
 135
 136 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 137 {
 138         struct fw_card *card = ctx->card;
 139
 140         card->driver->free_iso_context(ctx);
 141 }
 142
 143 int fw_iso_context_start(struct fw_iso_context *ctx,
 144                          int cycle, int sync, int tags)
 145 {
 146         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 147 }
 148
 149 int fw_iso_context_queue(struct fw_iso_context *ctx,
 150                          struct fw_iso_packet *packet,
 151                          struct fw_iso_buffer *buffer,
 152                          unsigned long payload)
 153 {
 154         struct fw_card *card = ctx->card;
 155
 156         return card->driver->queue_iso(ctx, packet, buffer, payload);
 157 }
 158
 159 int fw_iso_context_stop(struct fw_iso_context *ctx)
 160 {
 161         return ctx->card->driver->stop_iso(ctx);
 162 }
 163
 164 /*
 165  * Isochronous bus resource management (channels, bandwidth), client side
 166  */
 167
 168 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 169                             int bandwidth, bool allocate)
 170 {
 171         __be32 data[2];
 172         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 173
 174         /*
 175          * On a 1394a IRM with low contention, try < 1 is enough.
 176          * On a 1394-1995 IRM, we need at least try < 2.
 177          * Let's just do try < 5.
 178          */
 179         for (try = 0; try < 5; try++) {
 180                 new = allocate ? old - bandwidth : old + bandwidth;
 181                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 182                         break;
 183
 184                 data[0] = cpu_to_be32(old);
 185                 data[1] = cpu_to_be32(new);
 186                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 187                                 irm_id, generation, SCODE_100,
 188                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 189                                 data, sizeof(data))) {
 190                 case RCODE_GENERATION:
 191                         /* A generation change frees all bandwidth. */
 192                         return allocate ? -EAGAIN : bandwidth;
 193
 194                 case RCODE_COMPLETE:
 195                         if (be32_to_cpup(data) == old)
 196                                 return bandwidth;
 197
 198                         old = be32_to_cpup(data);
 199                         /* Fall through. */
 200                 }
 201         }
 202
 203         return -EIO;
 204 }
 205
 206 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 207                           __be32 channels_mask, u64 offset, bool allocate)
 208 {
 209         __be32 data[2], c, old = allocate ? cpu_to_be32(~0) : 0;
 210         int i, retry = 5;
 211
 212         for (i = 0; i < 32; i++) {
 213                 c = cpu_to_be32(1 << (31 - i));
 214                 if (!(channels_mask & c))
 215                         continue;
 216
 217                 if (allocate == !(old & c))
 218                         continue;
 219
 220                 data[0] = old;
 221                 data[1] = old ^ c;
 222                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 223                                            irm_id, generation, SCODE_100,
 224                                            offset, data, sizeof(data))) {
 225                 case RCODE_GENERATION:
 226                         /* A generation change frees all channels. */
 227                         return allocate ? -EAGAIN : i;
 228
 229                 case RCODE_COMPLETE:
 230                         if (data[0] == old)
 231                                 return i;
 232
 233                         old = data[0];
 234
 235                         /* Is the IRM 1394a-2000 compliant? */
 236                         if ((data[0] & c) != (data[1] & c))
 237                                 continue;
 238
 239                         /* 1394-1995 IRM, fall through to retry. */
 240                 default:
 241                         if (retry--)
 242                                 i--;
 243                 }
 244         }
 245
 246         return -EIO;
 247 }
 248
 249 static void deallocate_channel(struct fw_card *card, int irm_id,
 250                                int generation, int channel)
 251 {
 252         __be32 mask;
 253         u64 offset;
 254
 255         mask = channel < 32 ? cpu_to_be32(1 << (31 - channel)) :
 256                               cpu_to_be32(1 << (63 - channel));
 257         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 258                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 259
 260         manage_channel(card, irm_id, generation, mask, offset, false);
 261 }
 262
 263 /**
 264  * fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
 265  *
 266  * In parameters: card, generation, channels_mask, bandwidth, allocate
 267  * Out parameters: channel, bandwidth
 268  * This function blocks (sleeps) during communication with the IRM.
 269  * Allocates or deallocates at most one channel out of channels_mask.
 270  *
 271  * Returns channel < 0 if no channel was allocated or deallocated.
 272  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 273  *
 274  * If generation is stale, deallocations succeed but allocations fail with
 275  * channel = -EAGAIN.
 276  *
 277  * If channel (de)allocation fails, bandwidth (de)allocation fails too.
 278  * If bandwidth allocation fails, no channel will be allocated either.
 279  * If bandwidth deallocation fails, channel deallocation may still have been
 280  * successful.
 281  */
 282 void fw_iso_resource_manage(struct fw_card *card, int generation,
 283                             u64 channels_mask, int *channel, int *bandwidth,
 284                             bool allocate)
 285 {
 286         __be32 channels_hi = cpu_to_be32(channels_mask >> 32);
 287         __be32 channels_lo = cpu_to_be32(channels_mask);
 288         int irm_id, ret, c = -EINVAL;
 289
 290         spin_lock_irq(&card->lock);
 291         irm_id = card->irm_node->node_id;
 292         spin_unlock_irq(&card->lock);
 293
 294         if (channels_hi)
 295                 c = manage_channel(card, irm_id, generation, channels_hi,
 296                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
 297         if (channels_lo && c < 0) {
 298                 c = manage_channel(card, irm_id, generation, channels_lo,
 299                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
 300                 if (c >= 0)
 301                         c += 32;
 302         }
 303         *channel = c;
 304
 305         if (channels_mask != 0 && c < 0)
 306                 *bandwidth = 0;
 307
 308         if (*bandwidth == 0)
 309                 return;
 310
 311         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 312         if (ret < 0)
 313                 *bandwidth = 0;
 314
 315         if (ret < 0 && c >= 0 && allocate) {
 316                 deallocate_channel(card, irm_id, generation, c);
 317                 *channel = ret;
 318         }
 319 }