projects/linux·blob v5.13 · refs

223 lines · 5.4 KiB

1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * kernel API
4 *
5 * Copyright (C) 2005-2009 Rodolfo Giometti <[email protected]>
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
27static 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
41static 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
65struct 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
119kfree_pps:
120 kfree(pps);
121
122pps_register_source_exit:
123 pr_err("%s: unable to register source\n", info->name);
124
125 return ERR_PTR(err);
126}
127EXPORT_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
136void 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}
144EXPORT_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 */
159void 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}
223EXPORT_SYMBOL(pps_event);