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 kfree_pps; 113 } 114 115 dev_info(pps->dev, "new PPS source %s\n", info->name); 116 117 return pps; 118 119 kfree_pps: 120 kfree(pps); 121 122 pps_register_source_exit: 123 pr_err("%s: unable to register source\n", info->name); 124 125 return ERR_PTR(err); 126 } 127 EXPORT_SYMBOL(pps_register_source); 128 129 /* pps_unregister_source - remove a PPS source from the system 130 * @pps: the PPS source 131 * 132 * This function is used to remove a previously registered PPS source from 133 * the system. 134 */ 135 136 void pps_unregister_source(struct pps_device *pps) 137 { 138 pps_kc_remove(pps); 139 pps_unregister_cdev(pps); 140 141 /* don't have to kfree(pps) here because it will be done on 142 * device destruction */ 143 } 144 EXPORT_SYMBOL(pps_unregister_source); 145 146 /* pps_event - register a PPS event into the system 147 * @pps: the PPS device 148 * @ts: the event timestamp 149 * @event: the event type 150 * @data: userdef pointer 151 * 152 * This function is used by each PPS client in order to register a new 153 * PPS event into the system (it's usually called inside an IRQ handler). 154 * 155 * If an echo function is associated with the PPS device it will be called 156 * as: 157 * pps->info.echo(pps, event, data); 158 */ 159 void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event, 160 void *data) 161 { 162 unsigned long flags; 163 int captured = 0; 164 struct pps_ktime ts_real = { .sec = 0, .nsec = 0, .flags = 0 }; 165 166 /* check event type */ 167 BUG_ON((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0); 168 169 dev_dbg(pps->dev, "PPS event at %lld.%09ld\n", 170 (s64)ts->ts_real.tv_sec, ts->ts_real.tv_nsec); 171 172 timespec_to_pps_ktime(&ts_real, ts->ts_real); 173 174 spin_lock_irqsave(&pps->lock, flags); 175 176 /* Must call the echo function? */ 177 if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR))) 178 pps->info.echo(pps, event, data); 179 180 /* Check the event */ 181 pps->current_mode = pps->params.mode; 182 if (event & pps->params.mode & PPS_CAPTUREASSERT) { 183 /* We have to add an offset? */ 184 if (pps->params.mode & PPS_OFFSETASSERT) 185 pps_add_offset(&ts_real, 186 &pps->params.assert_off_tu); 187 188 /* Save the time stamp */ 189 pps->assert_tu = ts_real; 190 pps->assert_sequence++; 191 dev_dbg(pps->dev, "capture assert seq #%u\n", 192 pps->assert_sequence); 193 194 captured = ~0; 195 } 196 if (event & pps->params.mode & PPS_CAPTURECLEAR) { 197 /* We have to add an offset? */ 198 if (pps->params.mode & PPS_OFFSETCLEAR) 199 pps_add_offset(&ts_real, 200 &pps->params.clear_off_tu); 201 202 /* Save the time stamp */ 203 pps->clear_tu = ts_real; 204 pps->clear_sequence++; 205 dev_dbg(pps->dev, "capture clear seq #%u\n", 206 pps->clear_sequence); 207 208 captured = ~0; 209 } 210 211 pps_kc_event(pps, ts, event); 212 213 /* Wake up if captured something */ 214 if (captured) { 215 pps->last_ev++; 216 wake_up_interruptible_all(&pps->queue); 217 218 kill_fasync(&pps->async_queue, SIGIO, POLL_IN); 219 } 220 221 spin_unlock_irqrestore(&pps->lock, flags); 222 } 223 EXPORT_SYMBOL(pps_event); 224