1 /* 2 * PTP 1588 clock support 3 * 4 * Copyright (C) 2010 OMICRON electronics GmbH 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 #include <linux/idr.h> 21 #include <linux/device.h> 22 #include <linux/err.h> 23 #include <linux/init.h> 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/posix-clock.h> 27 #include <linux/pps_kernel.h> 28 #include <linux/slab.h> 29 #include <linux/syscalls.h> 30 #include <linux/uaccess.h> 31 32 #include "ptp_private.h" 33 34 #define PTP_MAX_ALARMS 4 35 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT) 36 #define PTP_PPS_EVENT PPS_CAPTUREASSERT 37 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC) 38 39 /* private globals */ 40 41 static dev_t ptp_devt; 42 static struct class *ptp_class; 43 44 static DEFINE_IDA(ptp_clocks_map); 45 46 /* time stamp event queue operations */ 47 48 static inline int queue_free(struct timestamp_event_queue *q) 49 { 50 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1; 51 } 52 53 static void enqueue_external_timestamp(struct timestamp_event_queue *queue, 54 struct ptp_clock_event *src) 55 { 56 struct ptp_extts_event *dst; 57 unsigned long flags; 58 s64 seconds; 59 u32 remainder; 60 61 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder); 62 63 spin_lock_irqsave(&queue->lock, flags); 64 65 dst = &queue->buf[queue->tail]; 66 dst->index = src->index; 67 dst->t.sec = seconds; 68 dst->t.nsec = remainder; 69 70 if (!queue_free(queue)) 71 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS; 72 73 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS; 74 75 spin_unlock_irqrestore(&queue->lock, flags); 76 } 77 78 static s32 scaled_ppm_to_ppb(long ppm) 79 { 80 /* 81 * The 'freq' field in the 'struct timex' is in parts per 82 * million, but with a 16 bit binary fractional field. 83 * 84 * We want to calculate 85 * 86 * ppb = scaled_ppm * 1000 / 2^16 87 * 88 * which simplifies to 89 * 90 * ppb = scaled_ppm * 125 / 2^13 91 */ 92 s64 ppb = 1 + ppm; 93 ppb *= 125; 94 ppb >>= 13; 95 return (s32) ppb; 96 } 97 98 /* posix clock implementation */ 99 100 static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp) 101 { 102 tp->tv_sec = 0; 103 tp->tv_nsec = 1; 104 return 0; 105 } 106 107 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp) 108 { 109 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 110 struct timespec64 ts = timespec_to_timespec64(*tp); 111 112 return ptp->info->settime64(ptp->info, &ts); 113 } 114 115 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec *tp) 116 { 117 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 118 struct timespec64 ts; 119 int err; 120 121 err = ptp->info->gettime64(ptp->info, &ts); 122 if (!err) 123 *tp = timespec64_to_timespec(ts); 124 return err; 125 } 126 127 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx) 128 { 129 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 130 struct ptp_clock_info *ops; 131 int err = -EOPNOTSUPP; 132 133 ops = ptp->info; 134 135 if (tx->modes & ADJ_SETOFFSET) { 136 struct timespec ts; 137 ktime_t kt; 138 s64 delta; 139 140 ts.tv_sec = tx->time.tv_sec; 141 ts.tv_nsec = tx->time.tv_usec; 142 143 if (!(tx->modes & ADJ_NANO)) 144 ts.tv_nsec *= 1000; 145 146 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC) 147 return -EINVAL; 148 149 kt = timespec_to_ktime(ts); 150 delta = ktime_to_ns(kt); 151 err = ops->adjtime(ops, delta); 152 } else if (tx->modes & ADJ_FREQUENCY) { 153 s32 ppb = scaled_ppm_to_ppb(tx->freq); 154 if (ppb > ops->max_adj || ppb < -ops->max_adj) 155 return -ERANGE; 156 err = ops->adjfreq(ops, ppb); 157 ptp->dialed_frequency = tx->freq; 158 } else if (tx->modes == 0) { 159 tx->freq = ptp->dialed_frequency; 160 err = 0; 161 } 162 163 return err; 164 } 165 166 static struct posix_clock_operations ptp_clock_ops = { 167 .owner = THIS_MODULE, 168 .clock_adjtime = ptp_clock_adjtime, 169 .clock_gettime = ptp_clock_gettime, 170 .clock_getres = ptp_clock_getres, 171 .clock_settime = ptp_clock_settime, 172 .ioctl = ptp_ioctl, 173 .open = ptp_open, 174 .poll = ptp_poll, 175 .read = ptp_read, 176 }; 177 178 static void delete_ptp_clock(struct posix_clock *pc) 179 { 180 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 181 182 mutex_destroy(&ptp->tsevq_mux); 183 mutex_destroy(&ptp->pincfg_mux); 184 ida_simple_remove(&ptp_clocks_map, ptp->index); 185 kfree(ptp); 186 } 187 188 /* public interface */ 189 190 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 191 struct device *parent) 192 { 193 struct ptp_clock *ptp; 194 int err = 0, index, major = MAJOR(ptp_devt); 195 196 if (info->n_alarm > PTP_MAX_ALARMS) 197 return ERR_PTR(-EINVAL); 198 199 /* Initialize a clock structure. */ 200 err = -ENOMEM; 201 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 202 if (ptp == NULL) 203 goto no_memory; 204 205 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL); 206 if (index < 0) { 207 err = index; 208 goto no_slot; 209 } 210 211 ptp->clock.ops = ptp_clock_ops; 212 ptp->clock.release = delete_ptp_clock; 213 ptp->info = info; 214 ptp->devid = MKDEV(major, index); 215 ptp->index = index; 216 spin_lock_init(&ptp->tsevq.lock); 217 mutex_init(&ptp->tsevq_mux); 218 mutex_init(&ptp->pincfg_mux); 219 init_waitqueue_head(&ptp->tsev_wq); 220 221 /* Create a new device in our class. */ 222 ptp->dev = device_create(ptp_class, parent, ptp->devid, ptp, 223 "ptp%d", ptp->index); 224 if (IS_ERR(ptp->dev)) 225 goto no_device; 226 227 dev_set_drvdata(ptp->dev, ptp); 228 229 err = ptp_populate_sysfs(ptp); 230 if (err) 231 goto no_sysfs; 232 233 /* Register a new PPS source. */ 234 if (info->pps) { 235 struct pps_source_info pps; 236 memset(&pps, 0, sizeof(pps)); 237 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 238 pps.mode = PTP_PPS_MODE; 239 pps.owner = info->owner; 240 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 241 if (!ptp->pps_source) { 242 pr_err("failed to register pps source\n"); 243 goto no_pps; 244 } 245 } 246 247 /* Create a posix clock. */ 248 err = posix_clock_register(&ptp->clock, ptp->devid); 249 if (err) { 250 pr_err("failed to create posix clock\n"); 251 goto no_clock; 252 } 253 254 return ptp; 255 256 no_clock: 257 if (ptp->pps_source) 258 pps_unregister_source(ptp->pps_source); 259 no_pps: 260 ptp_cleanup_sysfs(ptp); 261 no_sysfs: 262 device_destroy(ptp_class, ptp->devid); 263 no_device: 264 mutex_destroy(&ptp->tsevq_mux); 265 mutex_destroy(&ptp->pincfg_mux); 266 ida_simple_remove(&ptp_clocks_map, index); 267 no_slot: 268 kfree(ptp); 269 no_memory: 270 return ERR_PTR(err); 271 } 272 EXPORT_SYMBOL(ptp_clock_register); 273 274 int ptp_clock_unregister(struct ptp_clock *ptp) 275 { 276 ptp->defunct = 1; 277 wake_up_interruptible(&ptp->tsev_wq); 278 279 /* Release the clock's resources. */ 280 if (ptp->pps_source) 281 pps_unregister_source(ptp->pps_source); 282 ptp_cleanup_sysfs(ptp); 283 device_destroy(ptp_class, ptp->devid); 284 285 posix_clock_unregister(&ptp->clock); 286 return 0; 287 } 288 EXPORT_SYMBOL(ptp_clock_unregister); 289 290 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 291 { 292 struct pps_event_time evt; 293 294 switch (event->type) { 295 296 case PTP_CLOCK_ALARM: 297 break; 298 299 case PTP_CLOCK_EXTTS: 300 enqueue_external_timestamp(&ptp->tsevq, event); 301 wake_up_interruptible(&ptp->tsev_wq); 302 break; 303 304 case PTP_CLOCK_PPS: 305 pps_get_ts(&evt); 306 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 307 break; 308 309 case PTP_CLOCK_PPSUSR: 310 pps_event(ptp->pps_source, &event->pps_times, 311 PTP_PPS_EVENT, NULL); 312 break; 313 } 314 } 315 EXPORT_SYMBOL(ptp_clock_event); 316 317 int ptp_clock_index(struct ptp_clock *ptp) 318 { 319 return ptp->index; 320 } 321 EXPORT_SYMBOL(ptp_clock_index); 322 323 int ptp_find_pin(struct ptp_clock *ptp, 324 enum ptp_pin_function func, unsigned int chan) 325 { 326 struct ptp_pin_desc *pin = NULL; 327 int i; 328 329 mutex_lock(&ptp->pincfg_mux); 330 for (i = 0; i < ptp->info->n_pins; i++) { 331 if (ptp->info->pin_config[i].func == func && 332 ptp->info->pin_config[i].chan == chan) { 333 pin = &ptp->info->pin_config[i]; 334 break; 335 } 336 } 337 mutex_unlock(&ptp->pincfg_mux); 338 339 return pin ? i : -1; 340 } 341 EXPORT_SYMBOL(ptp_find_pin); 342 343 /* module operations */ 344 345 static void __exit ptp_exit(void) 346 { 347 class_destroy(ptp_class); 348 unregister_chrdev_region(ptp_devt, MINORMASK + 1); 349 ida_destroy(&ptp_clocks_map); 350 } 351 352 static int __init ptp_init(void) 353 { 354 int err; 355 356 ptp_class = class_create(THIS_MODULE, "ptp"); 357 if (IS_ERR(ptp_class)) { 358 pr_err("ptp: failed to allocate class\n"); 359 return PTR_ERR(ptp_class); 360 } 361 362 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp"); 363 if (err < 0) { 364 pr_err("ptp: failed to allocate device region\n"); 365 goto no_region; 366 } 367 368 ptp_class->dev_groups = ptp_groups; 369 pr_info("PTP clock support registered\n"); 370 return 0; 371 372 no_region: 373 class_destroy(ptp_class); 374 return err; 375 } 376 377 subsys_initcall(ptp_init); 378 module_exit(ptp_exit); 379 380 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 381 MODULE_DESCRIPTION("PTP clocks support"); 382 MODULE_LICENSE("GPL"); 383