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 ida_simple_remove(&ptp_clocks_map, ptp->index); 173 kfree(ptp); 174 } 175 176 /* public interface */ 177 178 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 179 struct device *parent) 180 { 181 struct ptp_clock *ptp; 182 int err = 0, index, major = MAJOR(ptp_devt); 183 184 if (info->n_alarm > PTP_MAX_ALARMS) 185 return ERR_PTR(-EINVAL); 186 187 /* Initialize a clock structure. */ 188 err = -ENOMEM; 189 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 190 if (ptp == NULL) 191 goto no_memory; 192 193 index = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL); 194 if (index < 0) { 195 err = index; 196 goto no_slot; 197 } 198 199 ptp->clock.ops = ptp_clock_ops; 200 ptp->clock.release = delete_ptp_clock; 201 ptp->info = info; 202 ptp->devid = MKDEV(major, index); 203 ptp->index = index; 204 spin_lock_init(&ptp->tsevq.lock); 205 mutex_init(&ptp->tsevq_mux); 206 init_waitqueue_head(&ptp->tsev_wq); 207 208 /* Create a new device in our class. */ 209 ptp->dev = device_create(ptp_class, parent, ptp->devid, ptp, 210 "ptp%d", ptp->index); 211 if (IS_ERR(ptp->dev)) 212 goto no_device; 213 214 dev_set_drvdata(ptp->dev, ptp); 215 216 err = ptp_populate_sysfs(ptp); 217 if (err) 218 goto no_sysfs; 219 220 /* Register a new PPS source. */ 221 if (info->pps) { 222 struct pps_source_info pps; 223 memset(&pps, 0, sizeof(pps)); 224 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 225 pps.mode = PTP_PPS_MODE; 226 pps.owner = info->owner; 227 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 228 if (!ptp->pps_source) { 229 pr_err("failed to register pps source\n"); 230 goto no_pps; 231 } 232 } 233 234 /* Create a posix clock. */ 235 err = posix_clock_register(&ptp->clock, ptp->devid); 236 if (err) { 237 pr_err("failed to create posix clock\n"); 238 goto no_clock; 239 } 240 241 return ptp; 242 243 no_clock: 244 if (ptp->pps_source) 245 pps_unregister_source(ptp->pps_source); 246 no_pps: 247 ptp_cleanup_sysfs(ptp); 248 no_sysfs: 249 device_destroy(ptp_class, ptp->devid); 250 no_device: 251 mutex_destroy(&ptp->tsevq_mux); 252 no_slot: 253 kfree(ptp); 254 no_memory: 255 return ERR_PTR(err); 256 } 257 EXPORT_SYMBOL(ptp_clock_register); 258 259 int ptp_clock_unregister(struct ptp_clock *ptp) 260 { 261 ptp->defunct = 1; 262 wake_up_interruptible(&ptp->tsev_wq); 263 264 /* Release the clock's resources. */ 265 if (ptp->pps_source) 266 pps_unregister_source(ptp->pps_source); 267 ptp_cleanup_sysfs(ptp); 268 device_destroy(ptp_class, ptp->devid); 269 270 posix_clock_unregister(&ptp->clock); 271 return 0; 272 } 273 EXPORT_SYMBOL(ptp_clock_unregister); 274 275 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 276 { 277 struct pps_event_time evt; 278 279 switch (event->type) { 280 281 case PTP_CLOCK_ALARM: 282 break; 283 284 case PTP_CLOCK_EXTTS: 285 enqueue_external_timestamp(&ptp->tsevq, event); 286 wake_up_interruptible(&ptp->tsev_wq); 287 break; 288 289 case PTP_CLOCK_PPS: 290 pps_get_ts(&evt); 291 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 292 break; 293 294 case PTP_CLOCK_PPSUSR: 295 pps_event(ptp->pps_source, &event->pps_times, 296 PTP_PPS_EVENT, NULL); 297 break; 298 } 299 } 300 EXPORT_SYMBOL(ptp_clock_event); 301 302 int ptp_clock_index(struct ptp_clock *ptp) 303 { 304 return ptp->index; 305 } 306 EXPORT_SYMBOL(ptp_clock_index); 307 308 /* module operations */ 309 310 static void __exit ptp_exit(void) 311 { 312 class_destroy(ptp_class); 313 unregister_chrdev_region(ptp_devt, MINORMASK + 1); 314 ida_destroy(&ptp_clocks_map); 315 } 316 317 static int __init ptp_init(void) 318 { 319 int err; 320 321 ptp_class = class_create(THIS_MODULE, "ptp"); 322 if (IS_ERR(ptp_class)) { 323 pr_err("ptp: failed to allocate class\n"); 324 return PTR_ERR(ptp_class); 325 } 326 327 err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp"); 328 if (err < 0) { 329 pr_err("ptp: failed to allocate device region\n"); 330 goto no_region; 331 } 332 333 ptp_class->dev_attrs = ptp_dev_attrs; 334 pr_info("PTP clock support registered\n"); 335 return 0; 336 337 no_region: 338 class_destroy(ptp_class); 339 return err; 340 } 341 342 subsys_initcall(ptp_init); 343 module_exit(ptp_exit); 344 345 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 346 MODULE_DESCRIPTION("PTP clocks support"); 347 MODULE_LICENSE("GPL"); 348