ptp_private.h

  1/* SPDX-License-Identifier: GPL-2.0-or-later */
  2/*
  3 * PTP 1588 clock support - private declarations for the core module.
  4 *
  5 * Copyright (C) 2010 OMICRON electronics GmbH
  6 */
  7#ifndef _PTP_PRIVATE_H_
  8#define _PTP_PRIVATE_H_
  9
 10#include <linux/cdev.h>
 11#include <linux/device.h>
 12#include <linux/kthread.h>
 13#include <linux/mutex.h>
 14#include <linux/posix-clock.h>
 15#include <linux/ptp_clock.h>
 16#include <linux/ptp_clock_kernel.h>
 17#include <linux/time.h>
 18#include <linux/list.h>
 19#include <linux/bitmap.h>
 20#include <linux/debugfs.h>
 21
 22#define PTP_MAX_TIMESTAMPS 128
 23#define PTP_BUF_TIMESTAMPS 30
 24#define PTP_DEFAULT_MAX_VCLOCKS 20
 25#define PTP_MAX_VCLOCKS_LIMIT (KMALLOC_MAX_SIZE/(sizeof(int)))
 26#define PTP_MAX_CHANNELS 2048
 27
 28enum {
 29	PTP_LOCK_PHYSICAL = 0,
 30	PTP_LOCK_VIRTUAL,
 31};
 32
 33struct timestamp_event_queue {
 34	struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
 35	int head;
 36	int tail;
 37	spinlock_t lock;
 38	struct list_head qlist;
 39	unsigned long *mask;
 40	struct dentry *debugfs_instance;
 41	struct debugfs_u32_array dfs_bitmap;
 42};
 43
 44struct ptp_clock {
 45	struct posix_clock clock;
 46	struct device dev;
 47	struct ptp_clock_info *info;
 48	dev_t devid;
 49	int index; /* index into clocks.map */
 50	struct pps_device *pps_source;
 51	long dialed_frequency; /* remembers the frequency adjustment */
 52	struct list_head tsevqs; /* timestamp fifo list */
 53	spinlock_t tsevqs_lock; /* protects tsevqs from concurrent access */
 54	struct mutex pincfg_mux; /* protect concurrent info->pin_config access */
 55	wait_queue_head_t tsev_wq;
 56	int defunct; /* tells readers to go away when clock is being removed */
 57	struct device_attribute *pin_dev_attr;
 58	struct attribute **pin_attr;
 59	struct attribute_group pin_attr_group;
 60	/* 1st entry is a pointer to the real group, 2nd is NULL terminator */
 61	const struct attribute_group *pin_attr_groups[2];
 62	struct kthread_worker *kworker;
 63	struct kthread_delayed_work aux_work;
 64	unsigned int max_vclocks;
 65	unsigned int n_vclocks;
 66	int *vclock_index;
 67	struct mutex n_vclocks_mux; /* protect concurrent n_vclocks access */
 68	bool is_virtual_clock;
 69	bool has_cycles;
 70	struct dentry *debugfs_root;
 71};
 72
 73#define info_to_vclock(d) container_of((d), struct ptp_vclock, info)
 74#define cc_to_vclock(d) container_of((d), struct ptp_vclock, cc)
 75#define dw_to_vclock(d) container_of((d), struct ptp_vclock, refresh_work)
 76
 77struct ptp_vclock {
 78	struct ptp_clock *pclock;
 79	struct ptp_clock_info info;
 80	struct ptp_clock *clock;
 81	struct hlist_node vclock_hash_node;
 82	struct cyclecounter cc;
 83	struct timecounter tc;
 84	struct mutex lock;	/* protects tc/cc */
 85};
 86
 87/*
 88 * The function queue_cnt() is safe for readers to call without
 89 * holding q->lock. Readers use this function to verify that the queue
 90 * is nonempty before proceeding with a dequeue operation. The fact
 91 * that a writer might concurrently increment the tail does not
 92 * matter, since the queue remains nonempty nonetheless.
 93 */
 94static inline int queue_cnt(const struct timestamp_event_queue *q)
 95{
 96	/*
 97	 * Paired with WRITE_ONCE() in enqueue_external_timestamp(),
 98	 * ptp_read(), extts_fifo_show().
 99	 */
100	int cnt = READ_ONCE(q->tail) - READ_ONCE(q->head);
101	return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
102}
103
104/* Check if ptp virtual clock is in use */
105static inline bool ptp_vclock_in_use(struct ptp_clock *ptp)
106{
107	bool in_use = false;
108
109	/* Virtual clocks can't be stacked on top of virtual clocks.
110	 * Avoid acquiring the n_vclocks_mux on virtual clocks, to allow this
111	 * function to be called from code paths where the n_vclocks_mux of the
112	 * parent physical clock is already held. Functionally that's not an
113	 * issue, but lockdep would complain, because they have the same lock
114	 * class.
115	 */
116	if (ptp->is_virtual_clock)
117		return false;
118
119	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
120		return true;
121
122	if (ptp->n_vclocks)
123		in_use = true;
124
125	mutex_unlock(&ptp->n_vclocks_mux);
126
127	return in_use;
128}
129
130/* Check if ptp clock shall be free running */
131static inline bool ptp_clock_freerun(struct ptp_clock *ptp)
132{
133	if (ptp->has_cycles)
134		return false;
135
136	return ptp_vclock_in_use(ptp);
137}
138
139extern const struct class ptp_class;
140
141/*
142 * see ptp_chardev.c
143 */
144
145void ptp_disable_all_events(struct ptp_clock *ptp);
146
147/* caller must hold pincfg_mux */
148int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
149		    enum ptp_pin_function func, unsigned int chan);
150
151long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
152	       unsigned long arg);
153
154int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode);
155
156int ptp_release(struct posix_clock_context *pccontext);
157
158ssize_t ptp_read(struct posix_clock_context *pccontext, uint flags, char __user *buf,
159		 size_t cnt);
160
161__poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
162		  poll_table *wait);
163
164/*
165 * see ptp_sysfs.c
166 */
167
168extern const struct attribute_group *ptp_groups[];
169
170int ptp_populate_pin_groups(struct ptp_clock *ptp);
171void ptp_cleanup_pin_groups(struct ptp_clock *ptp);
172
173struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock);
174void ptp_vclock_unregister(struct ptp_vclock *vclock);
175#endif