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/spinlock.h>
  30 #include <linux/vmalloc.h>
  31
  32 #include <asm/byteorder.h>
  33
  34 #include "core.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, direction);
  75                 __free_page(buffer->pages[j]);
  76         }
  77         kfree(buffer->pages);
  78  out:
  79         buffer->pages = NULL;
  80
  81         return -ENOMEM;
  82 }
  83 EXPORT_SYMBOL(fw_iso_buffer_init);
  84
  85 int fw_iso_buffer_map(struct fw_iso_buffer *buffer, struct vm_area_struct *vma)
  86 {
  87         unsigned long uaddr;
  88         int i, err;
  89
  90         uaddr = vma->vm_start;
  91         for (i = 0; i < buffer->page_count; i++) {
  92                 err = vm_insert_page(vma, uaddr, buffer->pages[i]);
  93                 if (err)
  94                         return err;
  95
  96                 uaddr += PAGE_SIZE;
  97         }
  98
  99         return 0;
 100 }
 101
 102 void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
 103                            struct fw_card *card)
 104 {
 105         int i;
 106         dma_addr_t address;
 107
 108         for (i = 0; i < buffer->page_count; i++) {
 109                 address = page_private(buffer->pages[i]);
 110                 dma_unmap_page(card->device, address,
 111                                PAGE_SIZE, buffer->direction);
 112                 __free_page(buffer->pages[i]);
 113         }
 114
 115         kfree(buffer->pages);
 116         buffer->pages = NULL;
 117 }
 118 EXPORT_SYMBOL(fw_iso_buffer_destroy);
 119
 120 struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
 121                 int type, int channel, int speed, size_t header_size,
 122                 fw_iso_callback_t callback, void *callback_data)
 123 {
 124         struct fw_iso_context *ctx;
 125
 126         ctx = card->driver->allocate_iso_context(card,
 127                                                  type, channel, header_size);
 128         if (IS_ERR(ctx))
 129                 return ctx;
 130
 131         ctx->card = card;
 132         ctx->type = type;
 133         ctx->channel = channel;
 134         ctx->speed = speed;
 135         ctx->header_size = header_size;
 136         ctx->callback = callback;
 137         ctx->callback_data = callback_data;
 138
 139         return ctx;
 140 }
 141 EXPORT_SYMBOL(fw_iso_context_create);
 142
 143 void fw_iso_context_destroy(struct fw_iso_context *ctx)
 144 {
 145         struct fw_card *card = ctx->card;
 146
 147         card->driver->free_iso_context(ctx);
 148 }
 149 EXPORT_SYMBOL(fw_iso_context_destroy);
 150
 151 int fw_iso_context_start(struct fw_iso_context *ctx,
 152                          int cycle, int sync, int tags)
 153 {
 154         return ctx->card->driver->start_iso(ctx, cycle, sync, tags);
 155 }
 156 EXPORT_SYMBOL(fw_iso_context_start);
 157
 158 int fw_iso_context_queue(struct fw_iso_context *ctx,
 159                          struct fw_iso_packet *packet,
 160                          struct fw_iso_buffer *buffer,
 161                          unsigned long payload)
 162 {
 163         struct fw_card *card = ctx->card;
 164
 165         return card->driver->queue_iso(ctx, packet, buffer, payload);
 166 }
 167 EXPORT_SYMBOL(fw_iso_context_queue);
 168
 169 int fw_iso_context_stop(struct fw_iso_context *ctx)
 170 {
 171         return ctx->card->driver->stop_iso(ctx);
 172 }
 173 EXPORT_SYMBOL(fw_iso_context_stop);
 174
 175 /*
 176  * Isochronous bus resource management (channels, bandwidth), client side
 177  */
 178
 179 static int manage_bandwidth(struct fw_card *card, int irm_id, int generation,
 180                             int bandwidth, bool allocate)
 181 {
 182         __be32 data[2];
 183         int try, new, old = allocate ? BANDWIDTH_AVAILABLE_INITIAL : 0;
 184
 185         /*
 186          * On a 1394a IRM with low contention, try < 1 is enough.
 187          * On a 1394-1995 IRM, we need at least try < 2.
 188          * Let's just do try < 5.
 189          */
 190         for (try = 0; try < 5; try++) {
 191                 new = allocate ? old - bandwidth : old + bandwidth;
 192                 if (new < 0 || new > BANDWIDTH_AVAILABLE_INITIAL)
 193                         break;
 194
 195                 data[0] = cpu_to_be32(old);
 196                 data[1] = cpu_to_be32(new);
 197                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 198                                 irm_id, generation, SCODE_100,
 199                                 CSR_REGISTER_BASE + CSR_BANDWIDTH_AVAILABLE,
 200                                 data, sizeof(data))) {
 201                 case RCODE_GENERATION:
 202                         /* A generation change frees all bandwidth. */
 203                         return allocate ? -EAGAIN : bandwidth;
 204
 205                 case RCODE_COMPLETE:
 206                         if (be32_to_cpup(data) == old)
 207                                 return bandwidth;
 208
 209                         old = be32_to_cpup(data);
 210                         /* Fall through. */
 211                 }
 212         }
 213
 214         return -EIO;
 215 }
 216
 217 static int manage_channel(struct fw_card *card, int irm_id, int generation,
 218                           u32 channels_mask, u64 offset, bool allocate)
 219 {
 220         __be32 data[2], c, all, old;
 221         int i, retry = 5;
 222
 223         old = all = allocate ? cpu_to_be32(~0) : 0;
 224
 225         for (i = 0; i < 32; i++) {
 226                 if (!(channels_mask & 1 << i))
 227                         continue;
 228
 229                 c = cpu_to_be32(1 << (31 - i));
 230                 if ((old & c) != (all & c))
 231                         continue;
 232
 233                 data[0] = old;
 234                 data[1] = old ^ c;
 235                 switch (fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
 236                                            irm_id, generation, SCODE_100,
 237                                            offset, data, sizeof(data))) {
 238                 case RCODE_GENERATION:
 239                         /* A generation change frees all channels. */
 240                         return allocate ? -EAGAIN : i;
 241
 242                 case RCODE_COMPLETE:
 243                         if (data[0] == old)
 244                                 return i;
 245
 246                         old = data[0];
 247
 248                         /* Is the IRM 1394a-2000 compliant? */
 249                         if ((data[0] & c) == (data[1] & c))
 250                                 continue;
 251
 252                         /* 1394-1995 IRM, fall through to retry. */
 253                 default:
 254                         if (retry--)
 255                                 i--;
 256                 }
 257         }
 258
 259         return -EIO;
 260 }
 261
 262 static void deallocate_channel(struct fw_card *card, int irm_id,
 263                                int generation, int channel)
 264 {
 265         u32 mask;
 266         u64 offset;
 267
 268         mask = channel < 32 ? 1 << channel : 1 << (channel - 32);
 269         offset = channel < 32 ? CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI :
 270                                 CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO;
 271
 272         manage_channel(card, irm_id, generation, mask, offset, false);
 273 }
 274
 275 /**
 276  * fw_iso_resource_manage - Allocate or deallocate a channel and/or bandwidth
 277  *
 278  * In parameters: card, generation, channels_mask, bandwidth, allocate
 279  * Out parameters: channel, bandwidth
 280  * This function blocks (sleeps) during communication with the IRM.
 281  *
 282  * Allocates or deallocates at most one channel out of channels_mask.
 283  * channels_mask is a bitfield with MSB for channel 63 and LSB for channel 0.
 284  * (Note, the IRM's CHANNELS_AVAILABLE is a big-endian bitfield with MSB for
 285  * channel 0 and LSB for channel 63.)
 286  * Allocates or deallocates as many bandwidth allocation units as specified.
 287  *
 288  * Returns channel < 0 if no channel was allocated or deallocated.
 289  * Returns bandwidth = 0 if no bandwidth was allocated or deallocated.
 290  *
 291  * If generation is stale, deallocations succeed but allocations fail with
 292  * channel = -EAGAIN.
 293  *
 294  * If channel allocation fails, no bandwidth will be allocated either.
 295  * If bandwidth allocation fails, no channel will be allocated either.
 296  * But deallocations of channel and bandwidth are tried independently
 297  * of each other's success.
 298  */
 299 void fw_iso_resource_manage(struct fw_card *card, int generation,
 300                             u64 channels_mask, int *channel, int *bandwidth,
 301                             bool allocate)
 302 {
 303         u32 channels_hi = channels_mask;        /* channels 31...0 */
 304         u32 channels_lo = channels_mask >> 32;  /* channels 63...32 */
 305         int irm_id, ret, c = -EINVAL;
 306
 307         spin_lock_irq(&card->lock);
 308         irm_id = card->irm_node->node_id;
 309         spin_unlock_irq(&card->lock);
 310
 311         if (channels_hi)
 312                 c = manage_channel(card, irm_id, generation, channels_hi,
 313                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_HI, allocate);
 314         if (channels_lo && c < 0) {
 315                 c = manage_channel(card, irm_id, generation, channels_lo,
 316                     CSR_REGISTER_BASE + CSR_CHANNELS_AVAILABLE_LO, allocate);
 317                 if (c >= 0)
 318                         c += 32;
 319         }
 320         *channel = c;
 321
 322         if (allocate && channels_mask != 0 && c < 0)
 323                 *bandwidth = 0;
 324
 325         if (*bandwidth == 0)
 326                 return;
 327
 328         ret = manage_bandwidth(card, irm_id, generation, *bandwidth, allocate);
 329         if (ret < 0)
 330                 *bandwidth = 0;
 331
 332         if (allocate && ret < 0 && c >= 0) {
 333                 deallocate_channel(card, irm_id, generation, c);
 334                 *channel = ret;
 335         }
 336 }