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