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