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