296 lines
6.9 KiB
C
296 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* PTP virtual clock driver
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*
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* Copyright 2021 NXP
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*/
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#include <linux/slab.h>
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#include <linux/hashtable.h>
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#include "ptp_private.h"
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#define PTP_VCLOCK_CC_SHIFT 31
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#define PTP_VCLOCK_CC_MULT (1 << PTP_VCLOCK_CC_SHIFT)
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#define PTP_VCLOCK_FADJ_SHIFT 9
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#define PTP_VCLOCK_FADJ_DENOMINATOR 15625ULL
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#define PTP_VCLOCK_REFRESH_INTERVAL (HZ * 2)
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/* protects vclock_hash addition/deletion */
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static DEFINE_SPINLOCK(vclock_hash_lock);
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static DEFINE_READ_MOSTLY_HASHTABLE(vclock_hash, 8);
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static void ptp_vclock_hash_add(struct ptp_vclock *vclock)
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{
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spin_lock(&vclock_hash_lock);
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hlist_add_head_rcu(&vclock->vclock_hash_node,
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&vclock_hash[vclock->clock->index % HASH_SIZE(vclock_hash)]);
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spin_unlock(&vclock_hash_lock);
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}
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static void ptp_vclock_hash_del(struct ptp_vclock *vclock)
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{
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spin_lock(&vclock_hash_lock);
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hlist_del_init_rcu(&vclock->vclock_hash_node);
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spin_unlock(&vclock_hash_lock);
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synchronize_rcu();
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}
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static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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unsigned long flags;
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s64 adj;
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adj = (s64)scaled_ppm << PTP_VCLOCK_FADJ_SHIFT;
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adj = div_s64(adj, PTP_VCLOCK_FADJ_DENOMINATOR);
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spin_lock_irqsave(&vclock->lock, flags);
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timecounter_read(&vclock->tc);
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vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;
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spin_unlock_irqrestore(&vclock->lock, flags);
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return 0;
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}
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static int ptp_vclock_adjtime(struct ptp_clock_info *ptp, s64 delta)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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unsigned long flags;
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spin_lock_irqsave(&vclock->lock, flags);
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timecounter_adjtime(&vclock->tc, delta);
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spin_unlock_irqrestore(&vclock->lock, flags);
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return 0;
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}
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static int ptp_vclock_gettime(struct ptp_clock_info *ptp,
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struct timespec64 *ts)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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unsigned long flags;
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u64 ns;
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spin_lock_irqsave(&vclock->lock, flags);
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ns = timecounter_read(&vclock->tc);
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spin_unlock_irqrestore(&vclock->lock, flags);
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*ts = ns_to_timespec64(ns);
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return 0;
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}
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static int ptp_vclock_gettimex(struct ptp_clock_info *ptp,
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struct timespec64 *ts,
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struct ptp_system_timestamp *sts)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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struct ptp_clock *pptp = vclock->pclock;
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struct timespec64 pts;
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unsigned long flags;
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int err;
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u64 ns;
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err = pptp->info->getcyclesx64(pptp->info, &pts, sts);
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if (err)
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return err;
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spin_lock_irqsave(&vclock->lock, flags);
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ns = timecounter_cyc2time(&vclock->tc, timespec64_to_ns(&pts));
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spin_unlock_irqrestore(&vclock->lock, flags);
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*ts = ns_to_timespec64(ns);
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return 0;
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}
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static int ptp_vclock_settime(struct ptp_clock_info *ptp,
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const struct timespec64 *ts)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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u64 ns = timespec64_to_ns(ts);
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unsigned long flags;
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spin_lock_irqsave(&vclock->lock, flags);
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timecounter_init(&vclock->tc, &vclock->cc, ns);
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spin_unlock_irqrestore(&vclock->lock, flags);
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return 0;
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}
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static int ptp_vclock_getcrosststamp(struct ptp_clock_info *ptp,
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struct system_device_crosststamp *xtstamp)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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struct ptp_clock *pptp = vclock->pclock;
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unsigned long flags;
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int err;
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u64 ns;
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err = pptp->info->getcrosscycles(pptp->info, xtstamp);
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if (err)
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return err;
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spin_lock_irqsave(&vclock->lock, flags);
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ns = timecounter_cyc2time(&vclock->tc, ktime_to_ns(xtstamp->device));
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spin_unlock_irqrestore(&vclock->lock, flags);
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xtstamp->device = ns_to_ktime(ns);
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return 0;
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}
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static long ptp_vclock_refresh(struct ptp_clock_info *ptp)
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{
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struct ptp_vclock *vclock = info_to_vclock(ptp);
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struct timespec64 ts;
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ptp_vclock_gettime(&vclock->info, &ts);
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return PTP_VCLOCK_REFRESH_INTERVAL;
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}
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static const struct ptp_clock_info ptp_vclock_info = {
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.owner = THIS_MODULE,
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.name = "ptp virtual clock",
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.max_adj = 500000000,
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.adjfine = ptp_vclock_adjfine,
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.adjtime = ptp_vclock_adjtime,
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.settime64 = ptp_vclock_settime,
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.do_aux_work = ptp_vclock_refresh,
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};
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static u64 ptp_vclock_read(const struct cyclecounter *cc)
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{
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struct ptp_vclock *vclock = cc_to_vclock(cc);
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struct ptp_clock *ptp = vclock->pclock;
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struct timespec64 ts = {};
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ptp->info->getcycles64(ptp->info, &ts);
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return timespec64_to_ns(&ts);
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}
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static const struct cyclecounter ptp_vclock_cc = {
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.read = ptp_vclock_read,
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.mask = CYCLECOUNTER_MASK(32),
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.mult = PTP_VCLOCK_CC_MULT,
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.shift = PTP_VCLOCK_CC_SHIFT,
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};
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struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
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{
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struct ptp_vclock *vclock;
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vclock = kzalloc(sizeof(*vclock), GFP_KERNEL);
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if (!vclock)
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return NULL;
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vclock->pclock = pclock;
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vclock->info = ptp_vclock_info;
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if (pclock->info->getcyclesx64)
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vclock->info.gettimex64 = ptp_vclock_gettimex;
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else
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vclock->info.gettime64 = ptp_vclock_gettime;
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if (pclock->info->getcrosscycles)
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vclock->info.getcrosststamp = ptp_vclock_getcrosststamp;
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vclock->cc = ptp_vclock_cc;
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snprintf(vclock->info.name, PTP_CLOCK_NAME_LEN, "ptp%d_virt",
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pclock->index);
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INIT_HLIST_NODE(&vclock->vclock_hash_node);
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spin_lock_init(&vclock->lock);
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vclock->clock = ptp_clock_register(&vclock->info, &pclock->dev);
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if (IS_ERR_OR_NULL(vclock->clock)) {
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kfree(vclock);
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return NULL;
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}
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timecounter_init(&vclock->tc, &vclock->cc, 0);
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ptp_schedule_worker(vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);
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ptp_vclock_hash_add(vclock);
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return vclock;
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}
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void ptp_vclock_unregister(struct ptp_vclock *vclock)
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{
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ptp_vclock_hash_del(vclock);
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ptp_clock_unregister(vclock->clock);
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kfree(vclock);
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}
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#if IS_BUILTIN(CONFIG_PTP_1588_CLOCK)
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int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
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{
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char name[PTP_CLOCK_NAME_LEN] = "";
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struct ptp_clock *ptp;
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struct device *dev;
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int num = 0;
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if (pclock_index < 0)
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return num;
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snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", pclock_index);
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dev = class_find_device_by_name(ptp_class, name);
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if (!dev)
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return num;
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ptp = dev_get_drvdata(dev);
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if (mutex_lock_interruptible(&ptp->n_vclocks_mux)) {
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put_device(dev);
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return num;
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}
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*vclock_index = kzalloc(sizeof(int) * ptp->n_vclocks, GFP_KERNEL);
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if (!(*vclock_index))
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goto out;
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memcpy(*vclock_index, ptp->vclock_index, sizeof(int) * ptp->n_vclocks);
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num = ptp->n_vclocks;
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out:
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mutex_unlock(&ptp->n_vclocks_mux);
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put_device(dev);
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return num;
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}
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EXPORT_SYMBOL(ptp_get_vclocks_index);
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ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index)
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{
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unsigned int hash = vclock_index % HASH_SIZE(vclock_hash);
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struct ptp_vclock *vclock;
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unsigned long flags;
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u64 ns;
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u64 vclock_ns = 0;
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ns = ktime_to_ns(*hwtstamp);
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rcu_read_lock();
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hlist_for_each_entry_rcu(vclock, &vclock_hash[hash], vclock_hash_node) {
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if (vclock->clock->index != vclock_index)
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continue;
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spin_lock_irqsave(&vclock->lock, flags);
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vclock_ns = timecounter_cyc2time(&vclock->tc, ns);
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spin_unlock_irqrestore(&vclock->lock, flags);
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break;
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}
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rcu_read_unlock();
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return ns_to_ktime(vclock_ns);
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}
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EXPORT_SYMBOL(ptp_convert_timestamp);
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#endif
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