1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * arch/sh/drivers/dma/dma-api.c 4 * 5 * SuperH-specific DMA management API 6 * 7 * Copyright (C) 2003, 2004, 2005 Paul Mundt 8 */ 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/spinlock.h> 12 #include <linux/proc_fs.h> 13 #include <linux/seq_file.h> 14 #include <linux/list.h> 15 #include <linux/platform_device.h> 16 #include <linux/mm.h> 17 #include <linux/sched.h> 18 #include <linux/slab.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, ®istered_dmac_list, list) { 33 if ((chan < info->first_vchannel_nr) || 34 (chan >= info->first_vchannel_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, ®istered_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(®istered_dmac_list))) 65 return nr; 66 67 list_for_each_entry(info, ®istered_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->vchan == 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 capabilities 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, ®istered_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 strscpy(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, ®istered_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_proc_show(struct seq_file *m, void *v) 310 { 311 struct dma_info *info = v; 312 313 if (list_empty(®istered_dmac_list)) 314 return 0; 315 316 /* 317 * Iterate over each registered DMAC 318 */ 319 list_for_each_entry(info, ®istered_dmac_list, list) { 320 int i; 321 322 /* 323 * Iterate over each channel 324 */ 325 for (i = 0; i < info->nr_channels; i++) { 326 struct dma_channel *channel = info->channels + i; 327 328 if (!(channel->flags & DMA_CONFIGURED)) 329 continue; 330 331 seq_printf(m, "%2d: %14s %s\n", i, 332 info->name, channel->dev_id); 333 } 334 } 335 336 return 0; 337 } 338 339 int register_dmac(struct dma_info *info) 340 { 341 unsigned int total_channels, i; 342 343 INIT_LIST_HEAD(&info->list); 344 345 printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n", 346 info->name, info->nr_channels, info->nr_channels > 1 ? "s" : ""); 347 348 BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels); 349 350 info->pdev = platform_device_register_simple(info->name, -1, 351 NULL, 0); 352 if (IS_ERR(info->pdev)) 353 return PTR_ERR(info->pdev); 354 355 /* 356 * Don't touch pre-configured channels 357 */ 358 if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) { 359 unsigned int size; 360 361 size = sizeof(struct dma_channel) * info->nr_channels; 362 363 info->channels = kzalloc(size, GFP_KERNEL); 364 if (!info->channels) 365 return -ENOMEM; 366 } 367 368 total_channels = get_nr_channels(); 369 info->first_vchannel_nr = total_channels; 370 for (i = 0; i < info->nr_channels; i++) { 371 struct dma_channel *chan = &info->channels[i]; 372 373 atomic_set(&chan->busy, 0); 374 375 chan->chan = info->first_channel_nr + i; 376 chan->vchan = info->first_channel_nr + i + total_channels; 377 378 memcpy(chan->dev_id, "Unused", 7); 379 380 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE) 381 chan->flags |= DMA_TEI_CAPABLE; 382 383 init_waitqueue_head(&chan->wait_queue); 384 dma_create_sysfs_files(chan, info); 385 } 386 387 list_add(&info->list, ®istered_dmac_list); 388 389 return 0; 390 } 391 EXPORT_SYMBOL(register_dmac); 392 393 void unregister_dmac(struct dma_info *info) 394 { 395 unsigned int i; 396 397 for (i = 0; i < info->nr_channels; i++) 398 dma_remove_sysfs_files(info->channels + i, info); 399 400 if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) 401 kfree(info->channels); 402 403 list_del(&info->list); 404 platform_device_unregister(info->pdev); 405 } 406 EXPORT_SYMBOL(unregister_dmac); 407 408 static int __init dma_api_init(void) 409 { 410 printk(KERN_NOTICE "DMA: Registering DMA API.\n"); 411 return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM; 412 } 413 subsys_initcall(dma_api_init); 414 415 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 416 MODULE_DESCRIPTION("DMA API for SuperH"); 417 MODULE_LICENSE("GPL v2"); 418