1 /* 2 * kernel API 3 * 4 * 5 * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 20 */ 21 22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 23 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/init.h> 27 #include <linux/sched.h> 28 #include <linux/time.h> 29 #include <linux/timex.h> 30 #include <linux/spinlock.h> 31 #include <linux/fs.h> 32 #include <linux/pps_kernel.h> 33 #include <linux/slab.h> 34 35 #include "kc.h" 36 37 /* 38 * Local functions 39 */ 40 41 static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) 42 { 43 ts->nsec += offset->nsec; 44 while (ts->nsec >= NSEC_PER_SEC) { 45 ts->nsec -= NSEC_PER_SEC; 46 ts->sec++; 47 } 48 while (ts->nsec < 0) { 49 ts->nsec += NSEC_PER_SEC; 50 ts->sec--; 51 } 52 ts->sec += offset->sec; 53 } 54 55 static void pps_echo_client_default(struct pps_device *pps, int event, 56 void *data) 57 { 58 dev_info(pps->dev, "echo %s %s\n", 59 event & PPS_CAPTUREASSERT ? "assert" : "", 60 event & PPS_CAPTURECLEAR ? "clear" : ""); 61 } 62 63 /* 64 * Exported functions 65 */ 66 67 /* pps_register_source - add a PPS source in the system 68 * @info: the PPS info struct 69 * @default_params: the default PPS parameters of the new source 70 * 71 * This function is used to add a new PPS source in the system. The new 72 * source is described by info's fields and it will have, as default PPS 73 * parameters, the ones specified into default_params. 74 * 75 * The function returns, in case of success, the PPS device. Otherwise 76 * ERR_PTR(errno). 77 */ 78 79 struct pps_device *pps_register_source(struct pps_source_info *info, 80 int default_params) 81 { 82 struct pps_device *pps; 83 int err; 84 85 /* Sanity checks */ 86 if ((info->mode & default_params) != default_params) { 87 pr_err("%s: unsupported default parameters\n", 88 info->name); 89 err = -EINVAL; 90 goto pps_register_source_exit; 91 } 92 if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { 93 pr_err("%s: unspecified time format\n", 94 info->name); 95 err = -EINVAL; 96 goto pps_register_source_exit; 97 } 98 99 /* Allocate memory for the new PPS source struct */ 100 pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); 101 if (pps == NULL) { 102 err = -ENOMEM; 103 goto pps_register_source_exit; 104 } 105 106 /* These initializations must be done before calling idr_alloc() 107 * in order to avoid reces into pps_event(). 108 */ 109 pps->params.api_version = PPS_API_VERS; 110 pps->params.mode = default_params; 111 pps->info = *info; 112 113 /* check for default echo function */ 114 if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) && 115 pps->info.echo == NULL) 116 pps->info.echo = pps_echo_client_default; 117 118 init_waitqueue_head(&pps->queue); 119 spin_lock_init(&pps->lock); 120 121 /* Create the char device */ 122 err = pps_register_cdev(pps); 123 if (err < 0) { 124 pr_err("%s: unable to create char device\n", 125 info->name); 126 goto kfree_pps; 127 } 128 129 dev_info(pps->dev, "new PPS source %s\n", info->name); 130 131 return pps; 132 133 kfree_pps: 134 kfree(pps); 135 136 pps_register_source_exit: 137 pr_err("%s: unable to register source\n", info->name); 138 139 return ERR_PTR(err); 140 } 141 EXPORT_SYMBOL(pps_register_source); 142 143 /* pps_unregister_source - remove a PPS source from the system 144 * @pps: the PPS source 145 * 146 * This function is used to remove a previously registered PPS source from 147 * the system. 148 */ 149 150 void pps_unregister_source(struct pps_device *pps) 151 { 152 pps_kc_remove(pps); 153 pps_unregister_cdev(pps); 154 155 /* don't have to kfree(pps) here because it will be done on 156 * device destruction */ 157 } 158 EXPORT_SYMBOL(pps_unregister_source); 159 160 /* pps_event - register a PPS event into the system 161 * @pps: the PPS device 162 * @ts: the event timestamp 163 * @event: the event type 164 * @data: userdef pointer 165 * 166 * This function is used by each PPS client in order to register a new 167 * PPS event into the system (it's usually called inside an IRQ handler). 168 * 169 * If an echo function is associated with the PPS device it will be called 170 * as: 171 * pps->info.echo(pps, event, data); 172 */ 173 void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, 174 void *data) 175 { 176 unsigned long flags; 177 int captured = 0; 178 struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; 179 180 /* check event type */ 181 BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); 182 183 dev_dbg(pps->dev, "PPS event at %lld.%09ld\n", 184 (s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec); 185 186 timespec_to_pps_ktime(&ts_real, ts->ts_real); 187 188 spin_lock_irqsave(&pps->lock, flags); 189 190 /* Must call the echo function? */ 191 if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) 192 pps->info.echo(pps, event, data); 193 194 /* Check the event */ 195 pps->current_mode = pps->params.mode; 196 if (event & pps->params.mode & PPS_CAPTUREASSERT) { 197 /* We have to add an offset? */ 198 if (pps->params.mode & PPS_OFFSETASSERT) 199 pps_add_offset(&ts_real, 200 &pps->params.assert_off_tu); 201 202 /* Save the time stamp */ 203 pps->assert_tu = ts_real; 204 pps->assert_sequence++; 205 dev_dbg(pps->dev, "capture assert seq #%u\n", 206 pps->assert_sequence); 207 208 captured = ~0; 209 } 210 if (event & pps->params.mode & PPS_CAPTURECLEAR) { 211 /* We have to add an offset? */ 212 if (pps->params.mode & PPS_OFFSETCLEAR) 213 pps_add_offset(&ts_real, 214 &pps->params.clear_off_tu); 215 216 /* Save the time stamp */ 217 pps->clear_tu = ts_real; 218 pps->clear_sequence++; 219 dev_dbg(pps->dev, "capture clear seq #%u\n", 220 pps->clear_sequence); 221 222 captured = ~0; 223 } 224 225 pps_kc_event(pps, ts, event); 226 227 /* Wake up if captured something */ 228 if (captured) { 229 pps->last_ev++; 230 wake_up_interruptible_all(&pps->queue); 231 232 kill_fasync(&pps->async_queue, SIGIO, POLL_IN); 233 } 234 235 spin_unlock_irqrestore(&pps->lock, flags); 236 } 237 EXPORT_SYMBOL(pps_event); 238