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/bitops.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_MAX_CLOCKS 8 36 #define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT) 37 #define PTP_PPS_EVENT PPS_CAPTUREASSERT 38 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC) 39 40 /* private globals */ 41 42 static dev_t ptp_devt; 43 static struct class *ptp_class; 44 45 static DECLARE_BITMAP(ptp_clocks_map, PTP_MAX_CLOCKS); 46 static DEFINE_MUTEX(ptp_clocks_mutex); /* protects 'ptp_clocks_map' */ 47 48 /* time stamp event queue operations */ 49 50 static inline int queue_free(struct timestamp_event_queue *q) 51 { 52 return PTP_MAX_TIMESTAMPS - queue_cnt(q) - 1; 53 } 54 55 static void enqueue_external_timestamp(struct timestamp_event_queue *queue, 56 struct ptp_clock_event *src) 57 { 58 struct ptp_extts_event *dst; 59 unsigned long flags; 60 s64 seconds; 61 u32 remainder; 62 63 seconds = div_u64_rem(src->timestamp, 1000000000, &remainder); 64 65 spin_lock_irqsave(&queue->lock, flags); 66 67 dst = &queue->buf[queue->tail]; 68 dst->index = src->index; 69 dst->t.sec = seconds; 70 dst->t.nsec = remainder; 71 72 if (!queue_free(queue)) 73 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS; 74 75 queue->tail = (queue->tail + 1) % PTP_MAX_TIMESTAMPS; 76 77 spin_unlock_irqrestore(&queue->lock, flags); 78 } 79 80 static s32 scaled_ppm_to_ppb(long ppm) 81 { 82 /* 83 * The 'freq' field in the 'struct timex' is in parts per 84 * million, but with a 16 bit binary fractional field. 85 * 86 * We want to calculate 87 * 88 * ppb = scaled_ppm * 1000 / 2^16 89 * 90 * which simplifies to 91 * 92 * ppb = scaled_ppm * 125 / 2^13 93 */ 94 s64 ppb = 1 + ppm; 95 ppb *= 125; 96 ppb >>= 13; 97 return (s32) ppb; 98 } 99 100 /* posix clock implementation */ 101 102 static int ptp_clock_getres(struct posix_clock *pc, struct timespec *tp) 103 { 104 tp->tv_sec = 0; 105 tp->tv_nsec = 1; 106 return 0; 107 } 108 109 static int ptp_clock_settime(struct posix_clock *pc, const struct timespec *tp) 110 { 111 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 112 return ptp->info->settime(ptp->info, tp); 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 return ptp->info->gettime(ptp->info, tp); 119 } 120 121 static int ptp_clock_adjtime(struct posix_clock *pc, struct timex *tx) 122 { 123 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 124 struct ptp_clock_info *ops; 125 int err = -EOPNOTSUPP; 126 127 ops = ptp->info; 128 129 if (tx->modes & ADJ_SETOFFSET) { 130 struct timespec ts; 131 ktime_t kt; 132 s64 delta; 133 134 ts.tv_sec = tx->time.tv_sec; 135 ts.tv_nsec = tx->time.tv_usec; 136 137 if (!(tx->modes & ADJ_NANO)) 138 ts.tv_nsec *= 1000; 139 140 if ((unsigned long) ts.tv_nsec >= NSEC_PER_SEC) 141 return -EINVAL; 142 143 kt = timespec_to_ktime(ts); 144 delta = ktime_to_ns(kt); 145 err = ops->adjtime(ops, delta); 146 147 } else if (tx->modes & ADJ_FREQUENCY) { 148 149 err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq)); 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); 172 173 /* Remove the clock from the bit map. */ 174 mutex_lock(&ptp_clocks_mutex); 175 clear_bit(ptp->index, ptp_clocks_map); 176 mutex_unlock(&ptp_clocks_mutex); 177 178 kfree(ptp); 179 } 180 181 /* public interface */ 182 183 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info) 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 /* Find a free clock slot and reserve it. */ 192 err = -EBUSY; 193 mutex_lock(&ptp_clocks_mutex); 194 index = find_first_zero_bit(ptp_clocks_map, PTP_MAX_CLOCKS); 195 if (index < PTP_MAX_CLOCKS) 196 set_bit(index, ptp_clocks_map); 197 else 198 goto no_slot; 199 200 /* Initialize a clock structure. */ 201 err = -ENOMEM; 202 ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL); 203 if (ptp == NULL) 204 goto no_memory; 205 206 ptp->clock.ops = ptp_clock_ops; 207 ptp->clock.release = delete_ptp_clock; 208 ptp->info = info; 209 ptp->devid = MKDEV(major, index); 210 ptp->index = index; 211 spin_lock_init(&ptp->tsevq.lock); 212 mutex_init(&ptp->tsevq_mux); 213 init_waitqueue_head(&ptp->tsev_wq); 214 215 /* Create a new device in our class. */ 216 ptp->dev = device_create(ptp_class, NULL, ptp->devid, ptp, 217 "ptp%d", ptp->index); 218 if (IS_ERR(ptp->dev)) 219 goto no_device; 220 221 dev_set_drvdata(ptp->dev, ptp); 222 223 err = ptp_populate_sysfs(ptp); 224 if (err) 225 goto no_sysfs; 226 227 /* Register a new PPS source. */ 228 if (info->pps) { 229 struct pps_source_info pps; 230 memset(&pps, 0, sizeof(pps)); 231 snprintf(pps.name, PPS_MAX_NAME_LEN, "ptp%d", index); 232 pps.mode = PTP_PPS_MODE; 233 pps.owner = info->owner; 234 ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS); 235 if (!ptp->pps_source) { 236 pr_err("failed to register pps source\n"); 237 goto no_pps; 238 } 239 } 240 241 /* Create a posix clock. */ 242 err = posix_clock_register(&ptp->clock, ptp->devid); 243 if (err) { 244 pr_err("failed to create posix clock\n"); 245 goto no_clock; 246 } 247 248 mutex_unlock(&ptp_clocks_mutex); 249 return ptp; 250 251 no_clock: 252 if (ptp->pps_source) 253 pps_unregister_source(ptp->pps_source); 254 no_pps: 255 ptp_cleanup_sysfs(ptp); 256 no_sysfs: 257 device_destroy(ptp_class, ptp->devid); 258 no_device: 259 mutex_destroy(&ptp->tsevq_mux); 260 kfree(ptp); 261 no_memory: 262 clear_bit(index, ptp_clocks_map); 263 no_slot: 264 mutex_unlock(&ptp_clocks_mutex); 265 return ERR_PTR(err); 266 } 267 EXPORT_SYMBOL(ptp_clock_register); 268 269 int ptp_clock_unregister(struct ptp_clock *ptp) 270 { 271 ptp->defunct = 1; 272 wake_up_interruptible(&ptp->tsev_wq); 273 274 /* Release the clock's resources. */ 275 if (ptp->pps_source) 276 pps_unregister_source(ptp->pps_source); 277 ptp_cleanup_sysfs(ptp); 278 device_destroy(ptp_class, ptp->devid); 279 280 posix_clock_unregister(&ptp->clock); 281 return 0; 282 } 283 EXPORT_SYMBOL(ptp_clock_unregister); 284 285 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 286 { 287 struct pps_event_time evt; 288 289 switch (event->type) { 290 291 case PTP_CLOCK_ALARM: 292 break; 293 294 case PTP_CLOCK_EXTTS: 295 enqueue_external_timestamp(&ptp->tsevq, event); 296 wake_up_interruptible(&ptp->tsev_wq); 297 break; 298 299 case PTP_CLOCK_PPS: 300 pps_get_ts(&evt); 301 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 302 break; 303 } 304 } 305 EXPORT_SYMBOL(ptp_clock_event); 306 307 /* module operations */ 308 309 static void __exit ptp_exit(void) 310 { 311 class_destroy(ptp_class); 312 unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS); 313 } 314 315 static int __init ptp_init(void) 316 { 317 int err; 318 319 ptp_class = class_create(THIS_MODULE, "ptp"); 320 if (IS_ERR(ptp_class)) { 321 pr_err("ptp: failed to allocate class\n"); 322 return PTR_ERR(ptp_class); 323 } 324 325 err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp"); 326 if (err < 0) { 327 pr_err("ptp: failed to allocate device region\n"); 328 goto no_region; 329 } 330 331 ptp_class->dev_attrs = ptp_dev_attrs; 332 pr_info("PTP clock support registered\n"); 333 return 0; 334 335 no_region: 336 class_destroy(ptp_class); 337 return err; 338 } 339 340 subsys_initcall(ptp_init); 341 module_exit(ptp_exit); 342 343 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>"); 344 MODULE_DESCRIPTION("PTP clocks support"); 345 MODULE_LICENSE("GPL"); 346