/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * PTP 1588 clock support - private declarations for the core module.
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 */
#ifndef _PTP_PRIVATE_H_
#define _PTP_PRIVATE_H_

#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/posix-clock.h>
#include <linux/ptp_clock.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/time.h>
#include <linux/list.h>
#include <linux/bitmap.h>
#include <linux/debugfs.h>

#define PTP_MAX_TIMESTAMPS 128
#define PTP_BUF_TIMESTAMPS 30
#define PTP_DEFAULT_MAX_VCLOCKS 20
#define PTP_MAX_VCLOCKS_LIMIT (KMALLOC_MAX_SIZE/(sizeof(int)))
#define PTP_MAX_CHANNELS 2048

enum {
        PTP_LOCK_PHYSICAL = 0,
        PTP_LOCK_VIRTUAL,
};

struct timestamp_event_queue {
        struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
        int head;
        int tail;
        spinlock_t lock;
        struct list_head qlist;
        unsigned long *mask;
        struct dentry *debugfs_instance;
        struct debugfs_u32_array dfs_bitmap;
};

struct ptp_clock {
        struct posix_clock clock;
        struct device dev;
        struct ptp_clock_info *info;
        dev_t devid;
        int index; /* index into clocks.map */
        struct pps_device *pps_source;
        long dialed_frequency; /* remembers the frequency adjustment */
        struct list_head tsevqs; /* timestamp fifo list */
        spinlock_t tsevqs_lock; /* protects tsevqs from concurrent access */
        struct mutex pincfg_mux; /* protect concurrent info->pin_config access */
        wait_queue_head_t tsev_wq;
        int defunct; /* tells readers to go away when clock is being removed */
        struct device_attribute *pin_dev_attr;
        struct attribute **pin_attr;
        struct attribute_group pin_attr_group;
        /* 1st entry is a pointer to the real group, 2nd is NULL terminator */
        const struct attribute_group *pin_attr_groups[2];
        struct kthread_worker *kworker;
        struct kthread_delayed_work aux_work;
        unsigned int max_vclocks;
        unsigned int n_vclocks;
        int *vclock_index;
        struct mutex n_vclocks_mux; /* protect concurrent n_vclocks access */
        bool is_virtual_clock;
        bool has_cycles;
        struct dentry *debugfs_root;
};

#define info_to_vclock(d) container_of((d), struct ptp_vclock, info)
#define cc_to_vclock(d) container_of((d), struct ptp_vclock, cc)
#define dw_to_vclock(d) container_of((d), struct ptp_vclock, refresh_work)

struct ptp_vclock {
        struct ptp_clock *pclock;
        struct ptp_clock_info info;
        struct ptp_clock *clock;
        struct hlist_node vclock_hash_node;
        struct cyclecounter cc;
        struct timecounter tc;
        struct mutex lock;      /* protects tc/cc */
};

/*
 * The function queue_cnt() is safe for readers to call without
 * holding q->lock. Readers use this function to verify that the queue
 * is nonempty before proceeding with a dequeue operation. The fact
 * that a writer might concurrently increment the tail does not
 * matter, since the queue remains nonempty nonetheless.
 */
static inline int queue_cnt(const struct timestamp_event_queue *q)
{
        /*
         * Paired with WRITE_ONCE() in enqueue_external_timestamp(),
         * ptp_read(), extts_fifo_show().
         */
        int cnt = READ_ONCE(q->tail) - READ_ONCE(q->head);
        return cnt < 0 ? PTP_MAX_TIMESTAMPS + cnt : cnt;
}

/* Check if ptp virtual clock is in use */
static inline bool ptp_vclock_in_use(struct ptp_clock *ptp)
{
        bool in_use = false;

        /* Virtual clocks can't be stacked on top of virtual clocks.
         * Avoid acquiring the n_vclocks_mux on virtual clocks, to allow this
         * function to be called from code paths where the n_vclocks_mux of the
         * parent physical clock is already held. Functionally that's not an
         * issue, but lockdep would complain, because they have the same lock
         * class.
         */
        if (ptp->is_virtual_clock)
                return false;

        if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
                return true;

        if (ptp->n_vclocks)
                in_use = true;

        mutex_unlock(&ptp->n_vclocks_mux);

        return in_use;
}

/* Check if ptp clock shall be free running */
static inline bool ptp_clock_freerun(struct ptp_clock *ptp)
{
        if (ptp->has_cycles)
                return false;

        return ptp_vclock_in_use(ptp);
}

extern const struct class ptp_class;

/*
 * see ptp_chardev.c
 */

void ptp_disable_all_events(struct ptp_clock *ptp);

/* caller must hold pincfg_mux */
int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
                    enum ptp_pin_function func, unsigned int chan);

long ptp_ioctl(struct posix_clock_context *pccontext, unsigned int cmd,
               unsigned long arg);

int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode);

int ptp_release(struct posix_clock_context *pccontext);

ssize_t ptp_read(struct posix_clock_context *pccontext, uint flags, char __user *buf,
                 size_t cnt);

__poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
                  poll_table *wait);

/*
 * see ptp_sysfs.c
 */

extern const struct attribute_group *ptp_groups[];

int ptp_populate_pin_groups(struct ptp_clock *ptp);
void ptp_cleanup_pin_groups(struct ptp_clock *ptp);

struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock);
void ptp_vclock_unregister(struct ptp_vclock *vclock);
#endif