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