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 return 1; /* always round timer functions to one nanosecond */ 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); 144 145 } else if (tx->modes & ADJ_FREQUENCY) { 146 147 err = ops->adjfreq(ops, scaled_ppm_to_ppb(tx->freq)); 148 } 149 150 return err; 151 } 152 153 static struct posix_clock_operations ptp_clock_ops = { 154 .owner = THIS_MODULE, 155 .clock_adjtime = ptp_clock_adjtime, 156 .clock_gettime = ptp_clock_gettime, 157 .clock_getres = ptp_clock_getres, 158 .clock_settime = ptp_clock_settime, 159 .ioctl = ptp_ioctl, 160 .open = ptp_open, 161 .poll = ptp_poll, 162 .read = ptp_read, 163 }; 164 165 static void delete_ptp_clock(struct posix_clock *pc) 166 { 167 struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock); 168 169 mutex_destroy(&ptp->tsevq_mux); 170 171 /* Remove the clock from the bit map. */ 172 mutex_lock(&ptp_clocks_mutex); 173 clear_bit(ptp->index, ptp_clocks_map); 174 mutex_unlock(&ptp_clocks_mutex); 175 176 kfree(ptp); 177 } 178 179 /* public interface */ 180 181 struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info) 182 { 183 struct ptp_clock *ptp; 184 int err = 0, index, major = MAJOR(ptp_devt); 185 186 if (info->n_alarm > PTP_MAX_ALARMS) 187 return ERR_PTR(-EINVAL); 188 189 /* Find a free clock slot and reserve it. */ 190 err = -EBUSY; 191 mutex_lock(&ptp_clocks_mutex); 192 index = find_first_zero_bit(ptp_clocks_map, PTP_MAX_CLOCKS); 193 if (index < PTP_MAX_CLOCKS) 194 set_bit(index, ptp_clocks_map); 195 else 196 goto no_slot; 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 ptp->clock.ops = ptp_clock_ops; 205 ptp->clock.release = delete_ptp_clock; 206 ptp->info = info; 207 ptp->devid = MKDEV(major, index); 208 ptp->index = index; 209 spin_lock_init(&ptp->tsevq.lock); 210 mutex_init(&ptp->tsevq_mux); 211 init_waitqueue_head(&ptp->tsev_wq); 212 213 /* Create a new device in our class. */ 214 ptp->dev = device_create(ptp_class, NULL, 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 mutex_unlock(&ptp_clocks_mutex); 247 return ptp; 248 249 no_clock: 250 if (ptp->pps_source) 251 pps_unregister_source(ptp->pps_source); 252 no_pps: 253 ptp_cleanup_sysfs(ptp); 254 no_sysfs: 255 device_destroy(ptp_class, ptp->devid); 256 no_device: 257 mutex_destroy(&ptp->tsevq_mux); 258 kfree(ptp); 259 no_memory: 260 clear_bit(index, ptp_clocks_map); 261 no_slot: 262 mutex_unlock(&ptp_clocks_mutex); 263 return ERR_PTR(err); 264 } 265 EXPORT_SYMBOL(ptp_clock_register); 266 267 int ptp_clock_unregister(struct ptp_clock *ptp) 268 { 269 ptp->defunct = 1; 270 wake_up_interruptible(&ptp->tsev_wq); 271 272 /* Release the clock's resources. */ 273 if (ptp->pps_source) 274 pps_unregister_source(ptp->pps_source); 275 ptp_cleanup_sysfs(ptp); 276 device_destroy(ptp_class, ptp->devid); 277 278 posix_clock_unregister(&ptp->clock); 279 return 0; 280 } 281 EXPORT_SYMBOL(ptp_clock_unregister); 282 283 void ptp_clock_event(struct ptp_clock *ptp, struct ptp_clock_event *event) 284 { 285 struct pps_event_time evt; 286 287 switch (event->type) { 288 289 case PTP_CLOCK_ALARM: 290 break; 291 292 case PTP_CLOCK_EXTTS: 293 enqueue_external_timestamp(&ptp->tsevq, event); 294 wake_up_interruptible(&ptp->tsev_wq); 295 break; 296 297 case PTP_CLOCK_PPS: 298 pps_get_ts(&evt); 299 pps_event(ptp->pps_source, &evt, PTP_PPS_EVENT, NULL); 300 break; 301 } 302 } 303 EXPORT_SYMBOL(ptp_clock_event); 304 305 /* module operations */ 306 307 static void __exit ptp_exit(void) 308 { 309 class_destroy(ptp_class); 310 unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS); 311 } 312 313 static int __init ptp_init(void) 314 { 315 int err; 316 317 ptp_class = class_create(THIS_MODULE, "ptp"); 318 if (IS_ERR(ptp_class)) { 319 pr_err("ptp: failed to allocate class\n"); 320 return PTR_ERR(ptp_class); 321 } 322 323 err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp"); 324 if (err < 0) { 325 pr_err("ptp: failed to allocate device region\n"); 326 goto no_region; 327 } 328 329 ptp_class->dev_attrs = ptp_dev_attrs; 330 pr_info("PTP clock support registered\n"); 331 return 0; 332 333 no_region: 334 class_destroy(ptp_class); 335 return err; 336 } 337 338 subsys_initcall(ptp_init); 339 module_exit(ptp_exit); 340 341 MODULE_AUTHOR("Richard Cochran <richard.cochran@omicron.at>"); 342 MODULE_DESCRIPTION("PTP clocks support"); 343 MODULE_LICENSE("GPL"); 344