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(size: 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(objp: pps); |
121 | |
122 | pps_register_source_exit: |
123 | pr_err("%s: unable to register source\n" , info->name); |
124 | |
125 | return ERR_PTR(error: 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(kt: &ts_real, ts: 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: &ts_real, |
186 | offset: &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: &ts_real, |
200 | offset: &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(lock: &pps->lock, flags); |
222 | } |
223 | EXPORT_SYMBOL(pps_event); |
224 | |