arch/sh/drivers/dma/dma-api.c

   1 /*
   2  * arch/sh/drivers/dma/dma-api.c
   3  *
   4  * SuperH-specific DMA management API
   5  *
   6  * Copyright (C) 2003, 2004, 2005  Paul Mundt
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/list.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/mm.h>
  19 #include <asm/dma.h>
  20
  21 DEFINE_SPINLOCK(dma_spin_lock);
  22 static LIST_HEAD(registered_dmac_list);
  23
  24 struct dma_info *get_dma_info(unsigned int chan)
  25 {
  26         struct dma_info *info;
  27
  28         /*
  29          * Look for each DMAC's range to determine who the owner of
  30          * the channel is.
  31          */
  32         list_for_each_entry(info, &registered_dmac_list, list) {
  33                 if ((chan <  info->first_channel_nr) ||
  34                     (chan >= info->first_channel_nr + info->nr_channels))
  35                         continue;
  36
  37                 return info;
  38         }
  39
  40         return NULL;
  41 }
  42 EXPORT_SYMBOL(get_dma_info);
  43
  44 struct dma_info *get_dma_info_by_name(const char *dmac_name)
  45 {
  46         struct dma_info *info;
  47
  48         list_for_each_entry(info, &registered_dmac_list, list) {
  49                 if (dmac_name && (strcmp(dmac_name, info->name) != 0))
  50                         continue;
  51                 else
  52                         return info;
  53         }
  54
  55         return NULL;
  56 }
  57 EXPORT_SYMBOL(get_dma_info_by_name);
  58
  59 static unsigned int get_nr_channels(void)
  60 {
  61         struct dma_info *info;
  62         unsigned int nr = 0;
  63
  64         if (unlikely(list_empty(&registered_dmac_list)))
  65                 return nr;
  66
  67         list_for_each_entry(info, &registered_dmac_list, list)
  68                 nr += info->nr_channels;
  69
  70         return nr;
  71 }
  72
  73 struct dma_channel *get_dma_channel(unsigned int chan)
  74 {
  75         struct dma_info *info = get_dma_info(chan);
  76         struct dma_channel *channel;
  77         int i;
  78
  79         if (unlikely(!info))
  80                 return ERR_PTR(-EINVAL);
  81
  82         for (i = 0; i < info->nr_channels; i++) {
  83                 channel = &info->channels[i];
  84                 if (channel->chan == chan)
  85                         return channel;
  86         }
  87
  88         return NULL;
  89 }
  90 EXPORT_SYMBOL(get_dma_channel);
  91
  92 int get_dma_residue(unsigned int chan)
  93 {
  94         struct dma_info *info = get_dma_info(chan);
  95         struct dma_channel *channel = get_dma_channel(chan);
  96
  97         if (info->ops->get_residue)
  98                 return info->ops->get_residue(channel);
  99
 100         return 0;
 101 }
 102 EXPORT_SYMBOL(get_dma_residue);
 103
 104 static int search_cap(const char **haystack, const char *needle)
 105 {
 106         const char **p;
 107
 108         for (p = haystack; *p; p++)
 109                 if (strcmp(*p, needle) == 0)
 110                         return 1;
 111
 112         return 0;
 113 }
 114
 115 /**
 116  * request_dma_bycap - Allocate a DMA channel based on its capabilities
 117  * @dmac: List of DMA controllers to search
 118  * @caps: List of capabilites
 119  *
 120  * Search all channels of all DMA controllers to find a channel which
 121  * matches the requested capabilities. The result is the channel
 122  * number if a match is found, or %-ENODEV if no match is found.
 123  *
 124  * Note that not all DMA controllers export capabilities, in which
 125  * case they can never be allocated using this API, and so
 126  * request_dma() must be used specifying the channel number.
 127  */
 128 int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
 129 {
 130         unsigned int found = 0;
 131         struct dma_info *info;
 132         const char **p;
 133         int i;
 134
 135         BUG_ON(!dmac || !caps);
 136
 137         list_for_each_entry(info, &registered_dmac_list, list)
 138                 if (strcmp(*dmac, info->name) == 0) {
 139                         found = 1;
 140                         break;
 141                 }
 142
 143         if (!found)
 144                 return -ENODEV;
 145
 146         for (i = 0; i < info->nr_channels; i++) {
 147                 struct dma_channel *channel = &info->channels[i];
 148
 149                 if (unlikely(!channel->caps))
 150                         continue;
 151
 152                 for (p = caps; *p; p++) {
 153                         if (!search_cap(channel->caps, *p))
 154                                 break;
 155                         if (request_dma(channel->chan, dev_id) == 0)
 156                                 return channel->chan;
 157                 }
 158         }
 159
 160         return -EINVAL;
 161 }
 162 EXPORT_SYMBOL(request_dma_bycap);
 163
 164 int dmac_search_free_channel(const char *dev_id)
 165 {
 166         struct dma_channel *channel = { 0 };
 167         struct dma_info *info = get_dma_info(0);
 168         int i;
 169
 170         for (i = 0; i < info->nr_channels; i++) {
 171                 channel = &info->channels[i];
 172                 if (unlikely(!channel))
 173                         return -ENODEV;
 174
 175                 if (atomic_read(&channel->busy) == 0)
 176                         break;
 177         }
 178
 179         if (info->ops->request) {
 180                 int result = info->ops->request(channel);
 181                 if (result)
 182                         return result;
 183
 184                 atomic_set(&channel->busy, 1);
 185                 return channel->chan;
 186         }
 187
 188         return -ENOSYS;
 189 }
 190
 191 int request_dma(unsigned int chan, const char *dev_id)
 192 {
 193         struct dma_channel *channel = { 0 };
 194         struct dma_info *info = get_dma_info(chan);
 195         int result;
 196
 197         channel = get_dma_channel(chan);
 198         if (atomic_xchg(&channel->busy, 1))
 199                 return -EBUSY;
 200
 201         strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
 202
 203         if (info->ops->request) {
 204                 result = info->ops->request(channel);
 205                 if (result)
 206                         atomic_set(&channel->busy, 0);
 207
 208                 return result;
 209         }
 210
 211         return 0;
 212 }
 213 EXPORT_SYMBOL(request_dma);
 214
 215 void free_dma(unsigned int chan)
 216 {
 217         struct dma_info *info = get_dma_info(chan);
 218         struct dma_channel *channel = get_dma_channel(chan);
 219
 220         if (info->ops->free)
 221                 info->ops->free(channel);
 222
 223         atomic_set(&channel->busy, 0);
 224 }
 225 EXPORT_SYMBOL(free_dma);
 226
 227 void dma_wait_for_completion(unsigned int chan)
 228 {
 229         struct dma_info *info = get_dma_info(chan);
 230         struct dma_channel *channel = get_dma_channel(chan);
 231
 232         if (channel->flags & DMA_TEI_CAPABLE) {
 233                 wait_event(channel->wait_queue,
 234                            (info->ops->get_residue(channel) == 0));
 235                 return;
 236         }
 237
 238         while (info->ops->get_residue(channel))
 239                 cpu_relax();
 240 }
 241 EXPORT_SYMBOL(dma_wait_for_completion);
 242
 243 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
 244 {
 245         struct dma_info *info;
 246         unsigned int found = 0;
 247         int i;
 248
 249         list_for_each_entry(info, &registered_dmac_list, list)
 250                 if (strcmp(dmac, info->name) == 0) {
 251                         found = 1;
 252                         break;
 253                 }
 254
 255         if (unlikely(!found))
 256                 return -ENODEV;
 257
 258         for (i = 0; i < info->nr_channels; i++, caps++) {
 259                 struct dma_channel *channel;
 260
 261                 if ((info->first_channel_nr + i) != caps->ch_num)
 262                         return -EINVAL;
 263
 264                 channel = &info->channels[i];
 265                 channel->caps = caps->caplist;
 266         }
 267
 268         return 0;
 269 }
 270 EXPORT_SYMBOL(register_chan_caps);
 271
 272 void dma_configure_channel(unsigned int chan, unsigned long flags)
 273 {
 274         struct dma_info *info = get_dma_info(chan);
 275         struct dma_channel *channel = get_dma_channel(chan);
 276
 277         if (info->ops->configure)
 278                 info->ops->configure(channel, flags);
 279 }
 280 EXPORT_SYMBOL(dma_configure_channel);
 281
 282 int dma_xfer(unsigned int chan, unsigned long from,
 283              unsigned long to, size_t size, unsigned int mode)
 284 {
 285         struct dma_info *info = get_dma_info(chan);
 286         struct dma_channel *channel = get_dma_channel(chan);
 287
 288         channel->sar    = from;
 289         channel->dar    = to;
 290         channel->count  = size;
 291         channel->mode   = mode;
 292
 293         return info->ops->xfer(channel);
 294 }
 295 EXPORT_SYMBOL(dma_xfer);
 296
 297 int dma_extend(unsigned int chan, unsigned long op, void *param)
 298 {
 299         struct dma_info *info = get_dma_info(chan);
 300         struct dma_channel *channel = get_dma_channel(chan);
 301
 302         if (info->ops->extend)
 303                 return info->ops->extend(channel, op, param);
 304
 305         return -ENOSYS;
 306 }
 307 EXPORT_SYMBOL(dma_extend);
 308
 309 static int dma_read_proc(char *buf, char **start, off_t off,
 310                          int len, int *eof, void *data)
 311 {
 312         struct dma_info *info;
 313         char *p = buf;
 314
 315         if (list_empty(&registered_dmac_list))
 316                 return 0;
 317
 318         /*
 319          * Iterate over each registered DMAC
 320          */
 321         list_for_each_entry(info, &registered_dmac_list, list) {
 322                 int i;
 323
 324                 /*
 325                  * Iterate over each channel
 326                  */
 327                 for (i = 0; i < info->nr_channels; i++) {
 328                         struct dma_channel *channel = info->channels + i;
 329
 330                         if (!(channel->flags & DMA_CONFIGURED))
 331                                 continue;
 332
 333                         p += sprintf(p, "%2d: %14s    %s\n", i,
 334                                      info->name, channel->dev_id);
 335                 }
 336         }
 337
 338         return p - buf;
 339 }
 340
 341 int register_dmac(struct dma_info *info)
 342 {
 343         unsigned int total_channels, i;
 344
 345         INIT_LIST_HEAD(&info->list);
 346
 347         printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
 348                info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
 349
 350         BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
 351
 352         info->pdev = platform_device_register_simple((char *)info->name, -1,
 353                                                      NULL, 0);
 354         if (IS_ERR(info->pdev))
 355                 return PTR_ERR(info->pdev);
 356
 357         /*
 358          * Don't touch pre-configured channels
 359          */
 360         if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
 361                 unsigned int size;
 362
 363                 size = sizeof(struct dma_channel) * info->nr_channels;
 364
 365                 info->channels = kzalloc(size, GFP_KERNEL);
 366                 if (!info->channels)
 367                         return -ENOMEM;
 368         }
 369
 370         total_channels = get_nr_channels();
 371         for (i = 0; i < info->nr_channels; i++) {
 372                 struct dma_channel *chan = &info->channels[i];
 373
 374                 atomic_set(&chan->busy, 0);
 375
 376                 chan->chan  = info->first_channel_nr + i;
 377                 chan->vchan = info->first_channel_nr + i + total_channels;
 378
 379                 memcpy(chan->dev_id, "Unused", 7);
 380
 381                 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
 382                         chan->flags |= DMA_TEI_CAPABLE;
 383
 384                 init_waitqueue_head(&chan->wait_queue);
 385                 dma_create_sysfs_files(chan, info);
 386         }
 387
 388         list_add(&info->list, &registered_dmac_list);
 389
 390         return 0;
 391 }
 392 EXPORT_SYMBOL(register_dmac);
 393
 394 void unregister_dmac(struct dma_info *info)
 395 {
 396         unsigned int i;
 397
 398         for (i = 0; i < info->nr_channels; i++)
 399                 dma_remove_sysfs_files(info->channels + i, info);
 400
 401         if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
 402                 kfree(info->channels);
 403
 404         list_del(&info->list);
 405         platform_device_unregister(info->pdev);
 406 }
 407 EXPORT_SYMBOL(unregister_dmac);
 408
 409 static int __init dma_api_init(void)
 410 {
 411         printk(KERN_NOTICE "DMA: Registering DMA API.\n");
 412         create_proc_read_entry("dma", 0, 0, dma_read_proc, 0);
 413         return 0;
 414 }
 415 subsys_initcall(dma_api_init);
 416
 417 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 418 MODULE_DESCRIPTION("DMA API for SuperH");
 419 MODULE_LICENSE("GPL");