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 request_dma(unsigned int chan, const char *dev_id) 165 { 166 struct dma_channel *channel = { 0 }; 167 struct dma_info *info = get_dma_info(chan); 168 int result; 169 170 channel = get_dma_channel(chan); 171 if (atomic_xchg(&channel->busy, 1)) 172 return -EBUSY; 173 174 strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id)); 175 176 if (info->ops->request) { 177 result = info->ops->request(channel); 178 if (result) 179 atomic_set(&channel->busy, 0); 180 181 return result; 182 } 183 184 return 0; 185 } 186 EXPORT_SYMBOL(request_dma); 187 188 void free_dma(unsigned int chan) 189 { 190 struct dma_info *info = get_dma_info(chan); 191 struct dma_channel *channel = get_dma_channel(chan); 192 193 if (info->ops->free) 194 info->ops->free(channel); 195 196 atomic_set(&channel->busy, 0); 197 } 198 EXPORT_SYMBOL(free_dma); 199 200 void dma_wait_for_completion(unsigned int chan) 201 { 202 struct dma_info *info = get_dma_info(chan); 203 struct dma_channel *channel = get_dma_channel(chan); 204 205 if (channel->flags & DMA_TEI_CAPABLE) { 206 wait_event(channel->wait_queue, 207 (info->ops->get_residue(channel) == 0)); 208 return; 209 } 210 211 while (info->ops->get_residue(channel)) 212 cpu_relax(); 213 } 214 EXPORT_SYMBOL(dma_wait_for_completion); 215 216 int register_chan_caps(const char *dmac, struct dma_chan_caps *caps) 217 { 218 struct dma_info *info; 219 unsigned int found = 0; 220 int i; 221 222 list_for_each_entry(info, ®istered_dmac_list, list) 223 if (strcmp(dmac, info->name) == 0) { 224 found = 1; 225 break; 226 } 227 228 if (unlikely(!found)) 229 return -ENODEV; 230 231 for (i = 0; i < info->nr_channels; i++, caps++) { 232 struct dma_channel *channel; 233 234 if ((info->first_channel_nr + i) != caps->ch_num) 235 return -EINVAL; 236 237 channel = &info->channels[i]; 238 channel->caps = caps->caplist; 239 } 240 241 return 0; 242 } 243 EXPORT_SYMBOL(register_chan_caps); 244 245 void dma_configure_channel(unsigned int chan, unsigned long flags) 246 { 247 struct dma_info *info = get_dma_info(chan); 248 struct dma_channel *channel = get_dma_channel(chan); 249 250 if (info->ops->configure) 251 info->ops->configure(channel, flags); 252 } 253 EXPORT_SYMBOL(dma_configure_channel); 254 255 int dma_xfer(unsigned int chan, unsigned long from, 256 unsigned long to, size_t size, unsigned int mode) 257 { 258 struct dma_info *info = get_dma_info(chan); 259 struct dma_channel *channel = get_dma_channel(chan); 260 261 channel->sar = from; 262 channel->dar = to; 263 channel->count = size; 264 channel->mode = mode; 265 266 return info->ops->xfer(channel); 267 } 268 EXPORT_SYMBOL(dma_xfer); 269 270 int dma_extend(unsigned int chan, unsigned long op, void *param) 271 { 272 struct dma_info *info = get_dma_info(chan); 273 struct dma_channel *channel = get_dma_channel(chan); 274 275 if (info->ops->extend) 276 return info->ops->extend(channel, op, param); 277 278 return -ENOSYS; 279 } 280 EXPORT_SYMBOL(dma_extend); 281 282 static int dma_proc_show(struct seq_file *m, void *v) 283 { 284 struct dma_info *info = v; 285 286 if (list_empty(®istered_dmac_list)) 287 return 0; 288 289 /* 290 * Iterate over each registered DMAC 291 */ 292 list_for_each_entry(info, ®istered_dmac_list, list) { 293 int i; 294 295 /* 296 * Iterate over each channel 297 */ 298 for (i = 0; i < info->nr_channels; i++) { 299 struct dma_channel *channel = info->channels + i; 300 301 if (!(channel->flags & DMA_CONFIGURED)) 302 continue; 303 304 seq_printf(m, "%2d: %14s %s\n", i, 305 info->name, channel->dev_id); 306 } 307 } 308 309 return 0; 310 } 311 312 int register_dmac(struct dma_info *info) 313 { 314 unsigned int total_channels, i; 315 316 INIT_LIST_HEAD(&info->list); 317 318 printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n", 319 info->name, info->nr_channels, info->nr_channels > 1 ? "s" : ""); 320 321 BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels); 322 323 info->pdev = platform_device_register_simple(info->name, -1, 324 NULL, 0); 325 if (IS_ERR(info->pdev)) 326 return PTR_ERR(info->pdev); 327 328 /* 329 * Don't touch pre-configured channels 330 */ 331 if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) { 332 unsigned int size; 333 334 size = sizeof(struct dma_channel) * info->nr_channels; 335 336 info->channels = kzalloc(size, GFP_KERNEL); 337 if (!info->channels) 338 return -ENOMEM; 339 } 340 341 total_channels = get_nr_channels(); 342 info->first_vchannel_nr = total_channels; 343 for (i = 0; i < info->nr_channels; i++) { 344 struct dma_channel *chan = &info->channels[i]; 345 346 atomic_set(&chan->busy, 0); 347 348 chan->chan = info->first_channel_nr + i; 349 chan->vchan = info->first_channel_nr + i + total_channels; 350 351 memcpy(chan->dev_id, "Unused", 7); 352 353 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE) 354 chan->flags |= DMA_TEI_CAPABLE; 355 356 init_waitqueue_head(&chan->wait_queue); 357 dma_create_sysfs_files(chan, info); 358 } 359 360 list_add(&info->list, ®istered_dmac_list); 361 362 return 0; 363 } 364 EXPORT_SYMBOL(register_dmac); 365 366 void unregister_dmac(struct dma_info *info) 367 { 368 unsigned int i; 369 370 for (i = 0; i < info->nr_channels; i++) 371 dma_remove_sysfs_files(info->channels + i, info); 372 373 if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) 374 kfree(info->channels); 375 376 list_del(&info->list); 377 platform_device_unregister(info->pdev); 378 } 379 EXPORT_SYMBOL(unregister_dmac); 380 381 static int __init dma_api_init(void) 382 { 383 printk(KERN_NOTICE "DMA: Registering DMA API.\n"); 384 return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM; 385 } 386 subsys_initcall(dma_api_init); 387 388 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 389 MODULE_DESCRIPTION("DMA API for SuperH"); 390 MODULE_LICENSE("GPL v2"); 391