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 timespec64 *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 timespec64 *tp) 108 { 109 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 110 111 return ptp->info->settime64(ptp->info, tp); 112 } 113 114 static int ptp_clock_gettime(struct posix_clock *pc, struct timespec64 *tp) 115 { 116 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 117 int err; 118 119 err = ptp->info->gettime64(ptp->info, tp); 120 return err; 121 } 122 123 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx) 124 { 125 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 126 struct ptp_clock_info *ops; 127 int err = -EOPNOTSUPP; 128 129 ops = ptp->info; 130 131 if (tx->modes & ADJ_SETOFFSET) { 132 struct timespec64 ts; 133 ktime_t kt; 134 s64 delta; 135 136 ts.tv_sec = tx->time.tv_sec; 137 ts.tv_nsec = tx->time.tv_usec; 138 139 if (!(tx->modes & ADJ_NANO)) 140 ts.tv_nsec *= 1000; 141 142 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC) 143 return -EINVAL; 144 145 kt = timespec64_to_ktime(ts); 146 delta = ktime_to_ns(kt); 147 err = ops->adjtime(ops, delta); 148 } else if (tx->modes & ADJ_FREQUENCY) { 149 s32 ppb = scaled_ppm_to_ppb(tx->freq); 150 if (ppb > ops->max_adj || ppb < -ops->max_adj) 151 return -ERANGE; 152 if (ops->adjfine) 153 err = ops->adjfine(ops, tx->freq); 154 else 155 err = ops->adjfreq(ops, ppb); 156 ptp->dialed_frequency = tx->freq; 157 } else if (tx->modes == 0) { 158 tx->freq = ptp->dialed_frequency; 159 err = 0; 160 } 161 162 return err; 163 } 164 165 static struct posix_clock_operations ptp_clock_ops = { 166 .owner = THIS_MODULE, 167 .clock_adjtime = ptp_clock_adjtime, 168 .clock_gettime = ptp_clock_gettime, 169 .clock_getres = ptp_clock_getres, 170 .clock_settime = ptp_clock_settime, 171 .ioctl = ptp_ioctl, 172 .open = ptp_open, 173 .poll = ptp_poll, 174 .read = ptp_read, 175 }; 176 177 static void delete_ptp_clock(struct posix_clock *pc) 178 { 179 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 180 181 mutex_destroy(&ptp->tsevq_mux); 182 mutex_destroy(&ptp->pincfg_mux); 183 ida_simple_remove(&ptp_clocks_map, ptp->index); 184 kfree(ptp); 185 } 186 187 /* public interface */ 188 189 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 190 struct device *parent) 191 { 192 struct ptp_clock *ptp; 193 int err = 0, index, major = MAJOR(ptp_devt); 194 195 if (info->n_alarm > PTP_MAX_ALARMS) 196 return ERR_PTR(-EINVAL); 197 198 /* Initialize a clock structure. */ 199 err = -ENOMEM; 200 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 201 if (ptp == NULL) 202 goto no_memory; 203 204 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL); 205 if (index < 0) { 206 err = index; 207 goto no_slot; 208 } 209 210 ptp->clock.ops = ptp_clock_ops; 211 ptp->clock.release = delete_ptp_clock; 212 ptp->info = info; 213 ptp->devid = MKDEV(major, index); 214 ptp->index = index; 215 spin_lock_init(&ptp->tsevq.lock); 216 mutex_init(&ptp->tsevq_mux); 217 mutex_init(&ptp->pincfg_mux); 218 init_waitqueue_head(&ptp->tsev_wq); 219 220 err = ptp_populate_pin_groups(ptp); 221 if (err) 222 goto no_pin_groups; 223 224 /* Create a new device in our class. */ 225 ptp->dev = device_create_with_groups(ptp_class, parent, ptp->devid, 226 ptp, ptp->pin_attr_groups, 227 "ptp%d", ptp->index); 228 if (IS_ERR(ptp->dev)) 229 goto no_device; 230 231 /* Register a new PPS source. */ 232 if (info->pps) { 233 struct pps_source_info pps; 234 memset(&pps, 0, sizeof(pps)); 235 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 236 pps.mode = PTP_PPS_MODE; 237 pps.owner = info->owner; 238 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 239 if (!ptp->pps_source) { 240 pr_err("failed to register pps source\n"); 241 goto no_pps; 242 } 243 } 244 245 /* Create a posix clock. */ 246 err = posix_clock_register(&ptp->clock, ptp->devid); 247 if (err) { 248 pr_err("failed to create posix clock\n"); 249 goto no_clock; 250 } 251 252 return ptp; 253 254 no_clock: 255 if (ptp->pps_source) 256 pps_unregister_source(ptp->pps_source); 257 no_pps: 258 device_destroy(ptp_class, ptp->devid); 259 no_device: 260 ptp_cleanup_pin_groups(ptp); 261 no_pin_groups: 262 mutex_destroy(&ptp->tsevq_mux); 263 mutex_destroy(&ptp->pincfg_mux); 264 ida_simple_remove(&ptp_clocks_map, index); 265 no_slot: 266 kfree(ptp); 267 no_memory: 268 return ERR_PTR(err); 269 } 270 EXPORT_SYMBOL(ptp_clock_register); 271 272 int ptp_clock_unregister(struct ptp_clock *ptp) 273 { 274 ptp->defunct = 1; 275 wake_up_interruptible(&ptp->tsev_wq); 276 277 /* Release the clock's resources. */ 278 if (ptp->pps_source) 279 pps_unregister_source(ptp->pps_source); 280 281 device_destroy(ptp_class, ptp->devid); 282 ptp_cleanup_pin_groups(ptp); 283 284 posix_clock_unregister(&ptp->clock); 285 return 0; 286 } 287 EXPORT_SYMBOL(ptp_clock_unregister); 288 289 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 290 { 291 struct pps_event_time evt; 292 293 switch (event->type) { 294 295 case PTP_CLOCK_ALARM: 296 break; 297 298 case PTP_CLOCK_EXTTS: 299 enqueue_external_timestamp(&ptp->tsevq, event); 300 wake_up_interruptible(&ptp->tsev_wq); 301 break; 302 303 case PTP_CLOCK_PPS: 304 pps_get_ts(&evt); 305 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 306 break; 307 308 case PTP_CLOCK_PPSUSR: 309 pps_event(ptp->pps_source, &event->pps_times, 310 PTP_PPS_EVENT, NULL); 311 break; 312 } 313 } 314 EXPORT_SYMBOL(ptp_clock_event); 315 316 int ptp_clock_index(struct ptp_clock *ptp) 317 { 318 return ptp->index; 319 } 320 EXPORT_SYMBOL(ptp_clock_index); 321 322 int ptp_find_pin(struct ptp_clock *ptp, 323 enum ptp_pin_function func, unsigned int chan) 324 { 325 struct ptp_pin_desc *pin = NULL; 326 int i; 327 328 mutex_lock(&ptp->pincfg_mux); 329 for (i = 0; i < ptp->info->n_pins; i++) { 330 if (ptp->info->pin_config[i].func == func && 331 ptp->info->pin_config[i].chan == chan) { 332 pin = &ptp->info->pin_config[i]; 333 break; 334 } 335 } 336 mutex_unlock(&ptp->pincfg_mux); 337 338 return pin ? i : -1; 339 } 340 EXPORT_SYMBOL(ptp_find_pin); 341 342 /* module operations */ 343 344 static void __exit ptp_exit(void) 345 { 346 class_destroy(ptp_class); 347 unregister_chrdev_region(ptp_devt, MINORMASK + 1); 348 ida_destroy(&ptp_clocks_map); 349 } 350 351 static int __init ptp_init(void) 352 { 353 int err; 354 355 ptp_class = class_create(THIS_MODULE, "ptp"); 356 if (IS_ERR(ptp_class)) { 357 pr_err("ptp: failed to allocate class\n"); 358 return PTR_ERR(ptp_class); 359 } 360 361 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp"); 362 if (err < 0) { 363 pr_err("ptp: failed to allocate device region\n"); 364 goto no_region; 365 } 366 367 ptp_class->dev_groups = ptp_groups; 368 pr_info("PTP clock support registered\n"); 369 return 0; 370 371 no_region: 372 class_destroy(ptp_class); 373 return err; 374 } 375 376 subsys_initcall(ptp_init); 377 module_exit(ptp_exit); 378 379 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 380 MODULE_DESCRIPTION("PTP clocks support"); 381 MODULE_LICENSE("GPL"); 382