kernel/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/seq_file.h>
  17 #include <linux/list.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/mm.h>
  20 #include <linux/sched.h>
  21 #include <linux/slab.h>
  22 #include <asm/dma.h>
  23
  24 DEFINE_SPINLOCK(dma_spin_lock);
  25 static LIST_HEAD(registered_dmac_list);
  26
  27 struct dma_info *get_dma_info(unsigned int chan)
  28 {
  29         struct dma_info *info;
  30
  31         /*
  32          * Look for each DMAC's range to determine who the owner of
  33          * the channel is.
  34          */
  35         list_for_each_entry(info, &registered_dmac_list, list) {
  36                 if ((chan <  info->first_vchannel_nr) ||
  37                     (chan >= info->first_vchannel_nr + info->nr_channels))
  38                         continue;
  39
  40                 return info;
  41         }
  42
  43         return NULL;
  44 }
  45 EXPORT_SYMBOL(get_dma_info);
  46
  47 struct dma_info *get_dma_info_by_name(const char *dmac_name)
  48 {
  49         struct dma_info *info;
  50
  51         list_for_each_entry(info, &registered_dmac_list, list) {
  52                 if (dmac_name && (strcmp(dmac_name, info->name) != 0))
  53                         continue;
  54                 else
  55                         return info;
  56         }
  57
  58         return NULL;
  59 }
  60 EXPORT_SYMBOL(get_dma_info_by_name);
  61
  62 static unsigned int get_nr_channels(void)
  63 {
  64         struct dma_info *info;
  65         unsigned int nr = 0;
  66
  67         if (unlikely(list_empty(&registered_dmac_list)))
  68                 return nr;
  69
  70         list_for_each_entry(info, &registered_dmac_list, list)
  71                 nr += info->nr_channels;
  72
  73         return nr;
  74 }
  75
  76 struct dma_channel *get_dma_channel(unsigned int chan)
  77 {
  78         struct dma_info *info = get_dma_info(chan);
  79         struct dma_channel *channel;
  80         int i;
  81
  82         if (unlikely(!info))
  83                 return ERR_PTR(-EINVAL);
  84
  85         for (i = 0; i < info->nr_channels; i++) {
  86                 channel = &info->channels[i];
  87                 if (channel->vchan == chan)
  88                         return channel;
  89         }
  90
  91         return NULL;
  92 }
  93 EXPORT_SYMBOL(get_dma_channel);
  94
  95 int get_dma_residue(unsigned int chan)
  96 {
  97         struct dma_info *info = get_dma_info(chan);
  98         struct dma_channel *channel = get_dma_channel(chan);
  99
 100         if (info->ops->get_residue)
 101                 return info->ops->get_residue(channel);
 102
 103         return 0;
 104 }
 105 EXPORT_SYMBOL(get_dma_residue);
 106
 107 static int search_cap(const char **haystack, const char *needle)
 108 {
 109         const char **p;
 110
 111         for (p = haystack; *p; p++)
 112                 if (strcmp(*p, needle) == 0)
 113                         return 1;
 114
 115         return 0;
 116 }
 117
 118 /**
 119  * request_dma_bycap - Allocate a DMA channel based on its capabilities
 120  * @dmac: List of DMA controllers to search
 121  * @caps: List of capabilities
 122  *
 123  * Search all channels of all DMA controllers to find a channel which
 124  * matches the requested capabilities. The result is the channel
 125  * number if a match is found, or %-ENODEV if no match is found.
 126  *
 127  * Note that not all DMA controllers export capabilities, in which
 128  * case they can never be allocated using this API, and so
 129  * request_dma() must be used specifying the channel number.
 130  */
 131 int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
 132 {
 133         unsigned int found = 0;
 134         struct dma_info *info;
 135         const char **p;
 136         int i;
 137
 138         BUG_ON(!dmac || !caps);
 139
 140         list_for_each_entry(info, &registered_dmac_list, list)
 141                 if (strcmp(*dmac, info->name) == 0) {
 142                         found = 1;
 143                         break;
 144                 }
 145
 146         if (!found)
 147                 return -ENODEV;
 148
 149         for (i = 0; i < info->nr_channels; i++) {
 150                 struct dma_channel *channel = &info->channels[i];
 151
 152                 if (unlikely(!channel->caps))
 153                         continue;
 154
 155                 for (p = caps; *p; p++) {
 156                         if (!search_cap(channel->caps, *p))
 157                                 break;
 158                         if (request_dma(channel->chan, dev_id) == 0)
 159                                 return channel->chan;
 160                 }
 161         }
 162
 163         return -EINVAL;
 164 }
 165 EXPORT_SYMBOL(request_dma_bycap);
 166
 167 int dmac_search_free_channel(const char *dev_id)
 168 {
 169         struct dma_channel *channel = { 0 };
 170         struct dma_info *info = get_dma_info(0);
 171         int i;
 172
 173         for (i = 0; i < info->nr_channels; i++) {
 174                 channel = &info->channels[i];
 175                 if (unlikely(!channel))
 176                         return -ENODEV;
 177
 178                 if (atomic_read(&channel->busy) == 0)
 179                         break;
 180         }
 181
 182         if (info->ops->request) {
 183                 int result = info->ops->request(channel);
 184                 if (result)
 185                         return result;
 186
 187                 atomic_set(&channel->busy, 1);
 188                 return channel->chan;
 189         }
 190
 191         return -ENOSYS;
 192 }
 193
 194 int request_dma(unsigned int chan, const char *dev_id)
 195 {
 196         struct dma_channel *channel = { 0 };
 197         struct dma_info *info = get_dma_info(chan);
 198         int result;
 199
 200         channel = get_dma_channel(chan);
 201         if (atomic_xchg(&channel->busy, 1))
 202                 return -EBUSY;
 203
 204         strlcpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
 205
 206         if (info->ops->request) {
 207                 result = info->ops->request(channel);
 208                 if (result)
 209                         atomic_set(&channel->busy, 0);
 210
 211                 return result;
 212         }
 213
 214         return 0;
 215 }
 216 EXPORT_SYMBOL(request_dma);
 217
 218 void free_dma(unsigned int chan)
 219 {
 220         struct dma_info *info = get_dma_info(chan);
 221         struct dma_channel *channel = get_dma_channel(chan);
 222
 223         if (info->ops->free)
 224                 info->ops->free(channel);
 225
 226         atomic_set(&channel->busy, 0);
 227 }
 228 EXPORT_SYMBOL(free_dma);
 229
 230 void dma_wait_for_completion(unsigned int chan)
 231 {
 232         struct dma_info *info = get_dma_info(chan);
 233         struct dma_channel *channel = get_dma_channel(chan);
 234
 235         if (channel->flags & DMA_TEI_CAPABLE) {
 236                 wait_event(channel->wait_queue,
 237                            (info->ops->get_residue(channel) == 0));
 238                 return;
 239         }
 240
 241         while (info->ops->get_residue(channel))
 242                 cpu_relax();
 243 }
 244 EXPORT_SYMBOL(dma_wait_for_completion);
 245
 246 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps)
 247 {
 248         struct dma_info *info;
 249         unsigned int found = 0;
 250         int i;
 251
 252         list_for_each_entry(info, &registered_dmac_list, list)
 253                 if (strcmp(dmac, info->name) == 0) {
 254                         found = 1;
 255                         break;
 256                 }
 257
 258         if (unlikely(!found))
 259                 return -ENODEV;
 260
 261         for (i = 0; i < info->nr_channels; i++, caps++) {
 262                 struct dma_channel *channel;
 263
 264                 if ((info->first_channel_nr + i) != caps->ch_num)
 265                         return -EINVAL;
 266
 267                 channel = &info->channels[i];
 268                 channel->caps = caps->caplist;
 269         }
 270
 271         return 0;
 272 }
 273 EXPORT_SYMBOL(register_chan_caps);
 274
 275 void dma_configure_channel(unsigned int chan, unsigned long flags)
 276 {
 277         struct dma_info *info = get_dma_info(chan);
 278         struct dma_channel *channel = get_dma_channel(chan);
 279
 280         if (info->ops->configure)
 281                 info->ops->configure(channel, flags);
 282 }
 283 EXPORT_SYMBOL(dma_configure_channel);
 284
 285 int dma_xfer(unsigned int chan, unsigned long from,
 286              unsigned long to, size_t size, unsigned int mode)
 287 {
 288         struct dma_info *info = get_dma_info(chan);
 289         struct dma_channel *channel = get_dma_channel(chan);
 290
 291         channel->sar    = from;
 292         channel->dar    = to;
 293         channel->count  = size;
 294         channel->mode   = mode;
 295
 296         return info->ops->xfer(channel);
 297 }
 298 EXPORT_SYMBOL(dma_xfer);
 299
 300 int dma_extend(unsigned int chan, unsigned long op, void *param)
 301 {
 302         struct dma_info *info = get_dma_info(chan);
 303         struct dma_channel *channel = get_dma_channel(chan);
 304
 305         if (info->ops->extend)
 306                 return info->ops->extend(channel, op, param);
 307
 308         return -ENOSYS;
 309 }
 310 EXPORT_SYMBOL(dma_extend);
 311
 312 static int dma_proc_show(struct seq_file *m, void *v)
 313 {
 314         struct dma_info *info = v;
 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                         seq_printf(m, "%2d: %14s    %s\n", i,
 335                                    info->name, channel->dev_id);
 336                 }
 337         }
 338
 339         return 0;
 340 }
 341
 342 static int dma_proc_open(struct inode *inode, struct file *file)
 343 {
 344         return single_open(file, dma_proc_show, NULL);
 345 }
 346
 347 static const struct file_operations dma_proc_fops = {
 348         .open           = dma_proc_open,
 349         .read           = seq_read,
 350         .llseek         = seq_lseek,
 351         .release        = single_release,
 352 };
 353
 354 int register_dmac(struct dma_info *info)
 355 {
 356         unsigned int total_channels, i;
 357
 358         INIT_LIST_HEAD(&info->list);
 359
 360         printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
 361                info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
 362
 363         BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
 364
 365         info->pdev = platform_device_register_simple(info->name, -1,
 366                                                      NULL, 0);
 367         if (IS_ERR(info->pdev))
 368                 return PTR_ERR(info->pdev);
 369
 370         /*
 371          * Don't touch pre-configured channels
 372          */
 373         if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
 374                 unsigned int size;
 375
 376                 size = sizeof(struct dma_channel) * info->nr_channels;
 377
 378                 info->channels = kzalloc(size, GFP_KERNEL);
 379                 if (!info->channels)
 380                         return -ENOMEM;
 381         }
 382
 383         total_channels = get_nr_channels();
 384         info->first_vchannel_nr = total_channels;
 385         for (i = 0; i < info->nr_channels; i++) {
 386                 struct dma_channel *chan = &info->channels[i];
 387
 388                 atomic_set(&chan->busy, 0);
 389
 390                 chan->chan  = info->first_channel_nr + i;
 391                 chan->vchan = info->first_channel_nr + i + total_channels;
 392
 393                 memcpy(chan->dev_id, "Unused", 7);
 394
 395                 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
 396                         chan->flags |= DMA_TEI_CAPABLE;
 397
 398                 init_waitqueue_head(&chan->wait_queue);
 399                 dma_create_sysfs_files(chan, info);
 400         }
 401
 402         list_add(&info->list, &registered_dmac_list);
 403
 404         return 0;
 405 }
 406 EXPORT_SYMBOL(register_dmac);
 407
 408 void unregister_dmac(struct dma_info *info)
 409 {
 410         unsigned int i;
 411
 412         for (i = 0; i < info->nr_channels; i++)
 413                 dma_remove_sysfs_files(info->channels + i, info);
 414
 415         if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
 416                 kfree(info->channels);
 417
 418         list_del(&info->list);
 419         platform_device_unregister(info->pdev);
 420 }
 421 EXPORT_SYMBOL(unregister_dmac);
 422
 423 static int __init dma_api_init(void)
 424 {
 425         printk(KERN_NOTICE "DMA: Registering DMA API.\n");
 426         return proc_create("dma", 0, NULL, &dma_proc_fops) ? 0 : -ENOMEM;
 427 }
 428 subsys_initcall(dma_api_init);
 429
 430 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 431 MODULE_DESCRIPTION("DMA API for SuperH");
 432 MODULE_LICENSE("GPL");