1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * kernel API 4 * 5 * Copyright (C) 2005-2009 Rodolfo Giometti <giometti@linux.it> 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/sched.h> 14 #include <linux/time.h> 15 #include <linux/timex.h> 16 #include <linux/spinlock.h> 17 #include <linux/fs.h> 18 #include <linux/pps_kernel.h> 19 #include <linux/slab.h> 20 21 #include "kc.h" 22 23 /* 24 * Local functions 25 */ 26 27 static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset) 28 { 29 ts->nsec += offset->nsec; 30 while (ts->nsec >= NSEC_PER_SEC) { 31 ts->nsec -= NSEC_PER_SEC; 32 ts->sec++; 33 } 34 while (ts->nsec < 0) { 35 ts->nsec += NSEC_PER_SEC; 36 ts->sec--; 37 } 38 ts->sec += offset->sec; 39 } 40 41 static void pps_echo_client_default(struct pps_device *pps, int event, 42 void *data) 43 { 44 dev_info(&pps->dev, "echo %s %s\n", 45 event & PPS_CAPTUREASSERT ? "assert" : "", 46 event & PPS_CAPTURECLEAR ? "clear" : ""); 47 } 48 49 /* 50 * Exported functions 51 */ 52 53 /* pps_register_source - add a PPS source in the system 54 * @info: the PPS info struct 55 * @default_params: the default PPS parameters of the new source 56 * 57 * This function is used to add a new PPS source in the system. The new 58 * source is described by info's fields and it will have, as default PPS 59 * parameters, the ones specified into default_params. 60 * 61 * The function returns, in case of success, the PPS device. Otherwise 62 * ERR_PTR(errno). 63 */ 64 65 struct pps_device *pps_register_source(struct pps_source_info *info, 66 int default_params) 67 { 68 struct pps_device *pps; 69 int err; 70 71 /* Sanity checks */ 72 if ((info->mode & default_params) != default_params) { 73 pr_err("%s: unsupported default parameters\n", 74 info->name); 75 err = -EINVAL; 76 goto pps_register_source_exit; 77 } 78 if ((info->mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) { 79 pr_err("%s: unspecified time format\n", 80 info->name); 81 err = -EINVAL; 82 goto pps_register_source_exit; 83 } 84 85 /* Allocate memory for the new PPS source struct */ 86 pps = kzalloc(sizeof(struct pps_device), GFP_KERNEL); 87 if (pps == NULL) { 88 err = -ENOMEM; 89 goto pps_register_source_exit; 90 } 91 92 /* These initializations must be done before calling idr_alloc() 93 * in order to avoid reces into pps_event(). 94 */ 95 pps->params.api_version = PPS_API_VERS; 96 pps->params.mode = default_params; 97 pps->info = *info; 98 99 /* check for default echo function */ 100 if ((pps->info.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) && 101 pps->info.echo == NULL) 102 pps->info.echo = pps_echo_client_default; 103 104 init_waitqueue_head(&pps->queue); 105 spin_lock_init(&pps->lock); 106 107 /* Create the char device */ 108 err = pps_register_cdev(pps); 109 if (err < 0) { 110 pr_err("%s: unable to create char device\n", 111 info->name); 112 goto pps_register_source_exit; 113 } 114 115 dev_dbg(&pps->dev, "new PPS source %s\n", info->name); 116 117 return pps; 118 119 pps_register_source_exit: 120 pr_err("%s: unable to register source\n", info->name); 121 122 return ERR_PTR(err); 123 } 124 EXPORT_SYMBOL(pps_register_source); 125 126 /* pps_unregister_source - remove a PPS source from the system 127 * @pps: the PPS source 128 * 129 * This function is used to remove a previously registered PPS source from 130 * the system. 131 */ 132 133 void pps_unregister_source(struct pps_device *pps) 134 { 135 pps_kc_remove(pps); 136 pps_unregister_cdev(pps); 137 138 /* don't have to kfree(pps) here because it will be done on 139 * device destruction */ 140 } 141 EXPORT_SYMBOL(pps_unregister_source); 142 143 /* pps_event - register a PPS event into the system 144 * @pps: the PPS device 145 * @ts: the event timestamp 146 * @event: the event type 147 * @data: userdef pointer 148 * 149 * This function is used by each PPS client in order to register a new 150 * PPS event into the system (it's usually called inside an IRQ handler). 151 * 152 * If an echo function is associated with the PPS device it will be called 153 * as: 154 * pps->info.echo(pps, event, data); 155 */ 156 void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, 157 void *data) 158 { 159 unsigned long flags; 160 int captured = 0; 161 struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; 162 163 /* check event type */ 164 BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); 165 166 dev_dbg(&pps->dev, "PPS event at %lld.%09ld\n", 167 (s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec); 168 169 timespec_to_pps_ktime(&ts_real, ts->ts_real); 170 171 spin_lock_irqsave(&pps->lock, flags); 172 173 /* Must call the echo function? */ 174 if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) 175 pps->info.echo(pps, event, data); 176 177 /* Check the event */ 178 pps->current_mode = pps->params.mode; 179 if (event & pps->params.mode & PPS_CAPTUREASSERT) { 180 /* We have to add an offset? */ 181 if (pps->params.mode & PPS_OFFSETASSERT) 182 pps_add_offset(&ts_real, 183 &pps->params.assert_off_tu); 184 185 /* Save the time stamp */ 186 pps->assert_tu = ts_real; 187 pps->assert_sequence++; 188 dev_dbg(&pps->dev, "capture assert seq #%u\n", 189 pps->assert_sequence); 190 191 captured = ~0; 192 } 193 if (event & pps->params.mode & PPS_CAPTURECLEAR) { 194 /* We have to add an offset? */ 195 if (pps->params.mode & PPS_OFFSETCLEAR) 196 pps_add_offset(&ts_real, 197 &pps->params.clear_off_tu); 198 199 /* Save the time stamp */ 200 pps->clear_tu = ts_real; 201 pps->clear_sequence++; 202 dev_dbg(&pps->dev, "capture clear seq #%u\n", 203 pps->clear_sequence); 204 205 captured = ~0; 206 } 207 208 pps_kc_event(pps, ts, event); 209 210 /* Wake up if captured something */ 211 if (captured) { 212 pps->last_ev++; 213 wake_up_interruptible_all(&pps->queue); 214 215 kill_fasync(&pps->async_queue, SIGIO, POLL_IN); 216 } 217 218 spin_unlock_irqrestore(&pps->lock, flags); 219 } 220 EXPORT_SYMBOL(pps_event); 221