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 NULL. 76 */ 77 78 struct pps_device *pps_register_source(struct pps_source_info *info, 79 int default_params) 80 { 81 struct pps_device *pps; 82 int err; 83 84 /* Sanity checks */ 85 if ((info->mode & default_params) != default_params) { 86 pr_err("%s: unsupported default parameters\n", 87 info->name); 88 err = -EINVAL; 89 goto pps_register_source_exit; 90 } 91 if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { 92 pr_err("%s: unspecified time format\n", 93 info->name); 94 err = -EINVAL; 95 goto pps_register_source_exit; 96 } 97 98 /* Allocate memory for the new PPS source struct */ 99 pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); 100 if (pps == NULL) { 101 err = -ENOMEM; 102 goto pps_register_source_exit; 103 } 104 105 /* These initializations must be done before calling idr_alloc() 106 * in order to avoid reces into pps_event(). 107 */ 108 pps->params.api_version = PPS_API_VERS; 109 pps->params.mode = default_params; 110 pps->info = *info; 111 112 /* check for default echo function */ 113 if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) && 114 pps->info.echo == NULL) 115 pps->info.echo = pps_echo_client_default; 116 117 init_waitqueue_head(&pps->queue); 118 spin_lock_init(&pps->lock); 119 120 /* Create the char device */ 121 err = pps_register_cdev(pps); 122 if (err < 0) { 123 pr_err("%s: unable to create char device\n", 124 info->name); 125 goto kfree_pps; 126 } 127 128 dev_info(pps->dev, "new PPS source %s\n", info->name); 129 130 return pps; 131 132 kfree_pps: 133 kfree(pps); 134 135 pps_register_source_exit: 136 pr_err("%s: unable to register source\n", info->name); 137 138 return NULL; 139 } 140 EXPORT_SYMBOL(pps_register_source); 141 142 /* pps_unregister_source - remove a PPS source from the system 143 * @pps: the PPS source 144 * 145 * This function is used to remove a previously registered PPS source from 146 * the system. 147 */ 148 149 void pps_unregister_source(struct pps_device *pps) 150 { 151 pps_kc_remove(pps); 152 pps_unregister_cdev(pps); 153 154 /* don't have to kfree(pps) here because it will be done on 155 * device destruction */ 156 } 157 EXPORT_SYMBOL(pps_unregister_source); 158 159 /* pps_event - register a PPS event into the system 160 * @pps: the PPS device 161 * @ts: the event timestamp 162 * @event: the event type 163 * @data: userdef pointer 164 * 165 * This function is used by each PPS client in order to register a new 166 * PPS event into the system (it's usually called inside an IRQ handler). 167 * 168 * If an echo function is associated with the PPS device it will be called 169 * as: 170 * pps->info.echo(pps, event, data); 171 */ 172 void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, 173 void *data) 174 { 175 unsigned long flags; 176 int captured = 0; 177 struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; 178 179 /* check event type */ 180 BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); 181 182 dev_dbg(pps->dev, "PPS event at %lld.%09ld\n", 183 (s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec); 184 185 timespec_to_pps_ktime(&ts_real, ts->ts_real); 186 187 spin_lock_irqsave(&pps->lock, flags); 188 189 /* Must call the echo function? */ 190 if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) 191 pps->info.echo(pps, event, data); 192 193 /* Check the event */ 194 pps->current_mode = pps->params.mode; 195 if (event & pps->params.mode & PPS_CAPTUREASSERT) { 196 /* We have to add an offset? */ 197 if (pps->params.mode & PPS_OFFSETASSERT) 198 pps_add_offset(&ts_real, 199 &pps->params.assert_off_tu); 200 201 /* Save the time stamp */ 202 pps->assert_tu = ts_real; 203 pps->assert_sequence++; 204 dev_dbg(pps->dev, "capture assert seq #%u\n", 205 pps->assert_sequence); 206 207 captured = ~0; 208 } 209 if (event & pps->params.mode & PPS_CAPTURECLEAR) { 210 /* We have to add an offset? */ 211 if (pps->params.mode & PPS_OFFSETCLEAR) 212 pps_add_offset(&ts_real, 213 &pps->params.clear_off_tu); 214 215 /* Save the time stamp */ 216 pps->clear_tu = ts_real; 217 pps->clear_sequence++; 218 dev_dbg(pps->dev, "capture clear seq #%u\n", 219 pps->clear_sequence); 220 221 captured = ~0; 222 } 223 224 pps_kc_event(pps, ts, event); 225 226 /* Wake up if captured something */ 227 if (captured) { 228 pps->last_ev++; 229 wake_up_interruptible_all(&pps->queue); 230 231 kill_fasync(&pps->async_queue, SIGIO, POLL_IN); 232 } 233 234 spin_unlock_irqrestore(&pps->lock, flags); 235 } 236 EXPORT_SYMBOL(pps_event); 237