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 <asm/byteorder.h>
  32
  33 #include "fw-topology.h"
  34 #include "fw-transaction.h"
  35
  36 /*
  37  * Isochronous DMA context management
  38  */
  39
  40 int fw_iso_buffer_init(struct fw_iso_buffer *buffer, struct fw_card *card,
  41                        int page_count, enum dma_data_direction direction)
  42 {
  43         int i, j;
  44         dma_addr_t address;
  45
  46         buffer->page_count = page_count;
  47         buffer->direction = direction;
  48
  49         buffer->pages = kmalloc(page_count * sizeof(buffer->pages[0]),
  50                                 GFP_KERNEL);
  51         if (buffer->pages == NULL)
  52                 goto out;
  53
  54         for (i = 0; i < buffer->page_count; i++) {
  55                 buffer->pages[i] = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
  56                 if (buffer->pages[i] == NULL)
  57                         goto out_pages;
  58
  59                 address = dma_map_page(card->device, buffer->pages[i],
  60                                        0, PAGE_SIZE, direction);
  61                 if (dma_mapping_error(card->device, address)) {
  62                         __free_page(buffer->pages[i]);
  63                         goto out_pages;
  64                 }
  65                 set_page_private(buffer->pages[i], address);
  66         }
  67
  68         return 0;
  69
  70  out_pages:
  71         for (j = 0; j < i; j++) {
  72                 address = page_private(buffer->pages[j]);
  73                 dma_unmap_page(card->device, address,
  74                                PAGE_SIZE, DMA_TO_DEVICE);
  75                 __free_page(buffer->pages[j]);
  76         }
  77         kfree(buffer->pages);
  78  out:
  79         buffer->pages = NULL;
  80
  81         return -ENOMEM;
  82 }
  83
  84 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
  85 {
  86         unsigned long uaddr;
  87         int i, err;
  88
  89         uaddr = vma->vm_start;
  90         for (i = 0; i < buffer->page_count; i++) {
  91                 err = vm_insert_page(vma, uaddr, buffer->pages[i]);
  92                 if (err)
  93                         return err;
  94
  95                 uaddr += PAGE_SIZE;
  96         }
  97
  98         return 0;
  99 }
 100
 101 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 102                            struct fw_card *card)
 103 {
 104         int i;
 105         dma_addr_t address;
 106
 107         for (i = 0; i < buffer->page_count; i++) {
 108                 address = page_private(buffer->pages[i]);
 109                 dma_unmap_page(card->device, address,
 110                                PAGE_SIZE, DMA_TO_DEVICE);
 111                 __free_page(buffer->pages[i]);
 112         }
 113
 114         kfree(buffer->pages);
 115         buffer->pages = NULL;
 116 }
 117
 118 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 119                 int type, int channel, int speed, size_t header_size,
 120                 fw_iso_callback_t callback, void *callback_data)
 121 {
 122         struct fw_iso_context *ctx;
 123
 124         ctx = card->driver->allocate_iso_context(card,
 125                                                  type, channel, header_size);
 126         if (IS_ERR(ctx))
 127                 return ctx;
 128
 129         ctx->card = card;
 130         ctx->type = type;
 131         ctx->channel = channel;
 132         ctx->speed = speed;
 133         ctx->header_size = header_size;
 134         ctx->callback = callback;
 135         ctx->callback_data = callback_data;
 136
 137         return ctx;
 138 }
 139
 140 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 141 {
 142         struct fw_card *card = ctx->card;
 143
 144         card->driver->free_iso_context(ctx);
 145 }
 146
 147 int fw_iso_context_start(struct fw_iso_context *ctx,
 148                          int cycle, int sync, int tags)
 149 {
 150         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 151 }
 152
 153 int fw_iso_context_queue(struct fw_iso_context *ctx,
 154                          struct fw_iso_packet *packet,
 155                          struct fw_iso_buffer *buffer,
 156                          unsigned long payload)
 157 {
 158         struct fw_card *card = ctx->card;
 159
 160         return card->driver->queue_iso(ctx, packet, buffer, payload);
 161 }
 162
 163 int fw_iso_context_stop(struct fw_iso_context *ctx)
 164 {
 165         return ctx->card->driver->stop_iso(ctx);
 166 }
 167
 168 /*
 169  * Isochronous bus resource management (channels, bandwidth), client side
 170  */
 171
 172 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 173                             int bandwidth, bool allocate)
 174 {
 175         __be32 data[2];
 176         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 177
 178         /*
 179          * On a 1394a IRM with low contention, try < 1 is enough.
 180          * On a 1394-1995 IRM, we need at least try < 2.
 181          * Let's just do try < 5.
 182          */
 183         for (try = 0; try < 5; try++) {
 184                 new = allocate ? old - bandwidth : old + bandwidth;
 185                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 186                         break;
 187
 188                 data[0] = cpu_to_be32(old);
 189                 data[1] = cpu_to_be32(new);
 190                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 191                                 irm_id, generation, SCODE_100,
 192                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 193                                 data, sizeof(data))) {
 194                 case RCODE_GENERATION:
 195                         /* A generation change frees all bandwidth. */
 196                         return allocate ? -EAGAIN : bandwidth;
 197
 198                 case RCODE_COMPLETE:
 199                         if (be32_to_cpup(data) == old)
 200                                 return bandwidth;
 201
 202                         old = be32_to_cpup(data);
 203                         /* Fall through. */
 204                 }
 205         }
 206
 207         return -EIO;
 208 }
 209
 210 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 211                           u32 channels_mask, u64 offset, bool allocate)
 212 {
 213         __be32 data[2], c, all, old;
 214         int i, retry = 5;
 215
 216         old = all = allocate ? cpu_to_be32(~0) : 0;
 217
 218         for (i = 0; i < 32; i++) {
 219                 if (!(channels_mask & 1 << i))
 220                         continue;
 221
 222                 c = cpu_to_be32(1 << (31 - i));
 223                 if ((old & c) != (all & c))
 224                         continue;
 225
 226                 data[0] = old;
 227                 data[1] = old ^ c;
 228                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 229                                            irm_id, generation, SCODE_100,
 230                                            offset, data, sizeof(data))) {
 231                 case RCODE_GENERATION:
 232                         /* A generation change frees all channels. */
 233                         return allocate ? -EAGAIN : i;
 234
 235                 case RCODE_COMPLETE:
 236                         if (data[0] == old)
 237                                 return i;
 238
 239                         old = data[0];
 240
 241                         /* Is the IRM 1394a-2000 compliant? */
 242                         if ((data[0] & c) == (data[1] & c))
 243                                 continue;
 244
 245                         /* 1394-1995 IRM, fall through to retry. */
 246                 default:
 247                         if (retry--)
 248                                 i--;
 249                 }
 250         }
 251
 252         return -EIO;
 253 }
 254
 255 static void deallocate_channel(struct fw_card *card, int irm_id,
 256                                int generation, int channel)
 257 {
 258         u32 mask;
 259         u64 offset;
 260
 261         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 262         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 263                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 264
 265         manage_channel(card, irm_id, generation, mask, offset, false);
 266 }
 267
 268 /**
 269  * fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
 270  *
 271  * In parameters: card, generation, channels_mask, bandwidth, allocate
 272  * Out parameters: channel, bandwidth
 273  * This function blocks (sleeps) during communication with the IRM.
 274  *
 275  * Allocates or deallocates at most one channel out of channels_mask.
 276  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 277  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 278  * channel 0 and LSB for channel 63.)
 279  * Allocates or deallocates as many bandwidth allocation units as specified.
 280  *
 281  * Returns channel < 0 if no channel was allocated or deallocated.
 282  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 283  *
 284  * If generation is stale, deallocations succeed but allocations fail with
 285  * channel = -EAGAIN.
 286  *
 287  * If channel allocation fails, no bandwidth will be allocated either.
 288  * If bandwidth allocation fails, no channel will be allocated either.
 289  * But deallocations of channel and bandwidth are tried independently
 290  * of each other's success.
 291  */
 292 void fw_iso_resource_manage(struct fw_card *card, int generation,
 293                             u64 channels_mask, int *channel, int *bandwidth,
 294                             bool allocate)
 295 {
 296         u32 channels_hi = channels_mask;        /* channels 31...0 */
 297         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 298         int irm_id, ret, c = -EINVAL;
 299
 300         spin_lock_irq(&card->lock);
 301         irm_id = card->irm_node->node_id;
 302         spin_unlock_irq(&card->lock);
 303
 304         if (channels_hi)
 305                 c = manage_channel(card, irm_id, generation, channels_hi,
 306                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
 307         if (channels_lo && c < 0) {
 308                 c = manage_channel(card, irm_id, generation, channels_lo,
 309                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
 310                 if (c >= 0)
 311                         c += 32;
 312         }
 313         *channel = c;
 314
 315         if (allocate && channels_mask != 0 && c < 0)
 316                 *bandwidth = 0;
 317
 318         if (*bandwidth == 0)
 319                 return;
 320
 321         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 322         if (ret < 0)
 323                 *bandwidth = 0;
 324
 325         if (allocate && ret < 0 && c >= 0) {
 326                 deallocate_channel(card, irm_id, generation, c);
 327                 *channel = ret;
 328         }
 329 }