Commit 5d43f951 authored by Yangbo Lu's avatar Yangbo Lu Committed by David S. Miller
Browse files

ptp: add ptp virtual clock driver framework 



This patch is to add ptp virtual clock driver framework
utilizing timecounter/cyclecounter.

The patch just exports two essential APIs for PTP driver.

- ptp_vclock_register()
- ptp_vclock_unregister()

Signed-off-by: default avatarYangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 88827353

drivers/ptp/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -3,7 +3,7 @@ 
# Makefile for PTP 1588 clock support.

#



ptp-y					:= ptp_clock.o ptp_chardev.o ptp_sysfs.o

ptp-y					:= ptp_clock.o ptp_chardev.o ptp_sysfs.o ptp_vclock.o

ptp_kvm-$(CONFIG_X86)			:= ptp_kvm_x86.o ptp_kvm_common.o

ptp_kvm-$(CONFIG_HAVE_ARM_SMCCC)	:= ptp_kvm_arm.o ptp_kvm_common.o

obj-$(CONFIG_PTP_1588_CLOCK)		+= ptp.o

drivers/ptp/ptp_private.h

+15 −0
Original line number Diff line number Diff line
@@ -48,6 +48,19 @@ struct ptp_clock { 
	struct kthread_delayed_work aux_work;

};



#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 cyclecounter cc;

	struct timecounter tc;

	spinlock_t 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
@@ -89,4 +102,6 @@ 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

drivers/ptp/ptp_vclock.c

0 → 100644
+150 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * PTP virtual clock driver

 *

 * Copyright 2021 NXP

 */

#include <linux/slab.h>

#include "ptp_private.h"



#define PTP_VCLOCK_CC_SHIFT		31

#define PTP_VCLOCK_CC_MULT		(1 << PTP_VCLOCK_CC_SHIFT)

#define PTP_VCLOCK_FADJ_SHIFT		9

#define PTP_VCLOCK_FADJ_DENOMINATOR	15625ULL

#define PTP_VCLOCK_REFRESH_INTERVAL	(HZ * 2)



static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)

{

	struct ptp_vclock *vclock = info_to_vclock(ptp);

	unsigned long flags;

	s64 adj;



	adj = (s64)scaled_ppm << PTP_VCLOCK_FADJ_SHIFT;

	adj = div_s64(adj, PTP_VCLOCK_FADJ_DENOMINATOR);



	spin_lock_irqsave(&vclock->lock, flags);

	timecounter_read(&vclock->tc);

	vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;

	spin_unlock_irqrestore(&vclock->lock, flags);



	return 0;

}



static int ptp_vclock_adjtime(struct ptp_clock_info *ptp, s64 delta)

{

	struct ptp_vclock *vclock = info_to_vclock(ptp);

	unsigned long flags;



	spin_lock_irqsave(&vclock->lock, flags);

	timecounter_adjtime(&vclock->tc, delta);

	spin_unlock_irqrestore(&vclock->lock, flags);



	return 0;

}



static int ptp_vclock_gettime(struct ptp_clock_info *ptp,

			      struct timespec64 *ts)

{

	struct ptp_vclock *vclock = info_to_vclock(ptp);

	unsigned long flags;

	u64 ns;



	spin_lock_irqsave(&vclock->lock, flags);

	ns = timecounter_read(&vclock->tc);

	spin_unlock_irqrestore(&vclock->lock, flags);

	*ts = ns_to_timespec64(ns);



	return 0;

}



static int ptp_vclock_settime(struct ptp_clock_info *ptp,

			      const struct timespec64 *ts)

{

	struct ptp_vclock *vclock = info_to_vclock(ptp);

	u64 ns = timespec64_to_ns(ts);

	unsigned long flags;



	spin_lock_irqsave(&vclock->lock, flags);

	timecounter_init(&vclock->tc, &vclock->cc, ns);

	spin_unlock_irqrestore(&vclock->lock, flags);



	return 0;

}



static long ptp_vclock_refresh(struct ptp_clock_info *ptp)

{

	struct ptp_vclock *vclock = info_to_vclock(ptp);

	struct timespec64 ts;



	ptp_vclock_gettime(&vclock->info, &ts);



	return PTP_VCLOCK_REFRESH_INTERVAL;

}



static const struct ptp_clock_info ptp_vclock_info = {

	.owner		= THIS_MODULE,

	.name		= "ptp virtual clock",

	/* The maximum ppb value that long scaled_ppm can support */

	.max_adj	= 32767999,

	.adjfine	= ptp_vclock_adjfine,

	.adjtime	= ptp_vclock_adjtime,

	.gettime64	= ptp_vclock_gettime,

	.settime64	= ptp_vclock_settime,

	.do_aux_work	= ptp_vclock_refresh,

};



static u64 ptp_vclock_read(const struct cyclecounter *cc)

{

	struct ptp_vclock *vclock = cc_to_vclock(cc);

	struct ptp_clock *ptp = vclock->pclock;

	struct timespec64 ts = {};



	if (ptp->info->gettimex64)

		ptp->info->gettimex64(ptp->info, &ts, NULL);

	else

		ptp->info->gettime64(ptp->info, &ts);



	return timespec64_to_ns(&ts);

}



static const struct cyclecounter ptp_vclock_cc = {

	.read	= ptp_vclock_read,

	.mask	= CYCLECOUNTER_MASK(32),

	.mult	= PTP_VCLOCK_CC_MULT,

	.shift	= PTP_VCLOCK_CC_SHIFT,

};



struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)

{

	struct ptp_vclock *vclock;



	vclock = kzalloc(sizeof(*vclock), GFP_KERNEL);

	if (!vclock)

		return NULL;



	vclock->pclock = pclock;

	vclock->info = ptp_vclock_info;

	vclock->cc = ptp_vclock_cc;



	snprintf(vclock->info.name, PTP_CLOCK_NAME_LEN, "ptp%d_virt",

		 pclock->index);



	spin_lock_init(&vclock->lock);



	vclock->clock = ptp_clock_register(&vclock->info, &pclock->dev);

	if (IS_ERR_OR_NULL(vclock->clock)) {

		kfree(vclock);

		return NULL;

	}



	timecounter_init(&vclock->tc, &vclock->cc, 0);

	ptp_schedule_worker(vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);



	return vclock;

}



void ptp_vclock_unregister(struct ptp_vclock *vclock)

{

	ptp_clock_unregister(vclock->clock);

	kfree(vclock);

}

include/linux/ptp_clock_kernel.h

+3 −1
Original line number Diff line number Diff line
@@ -11,7 +11,9 @@ 
#include <linux/device.h>

#include <linux/pps_kernel.h>

#include <linux/ptp_clock.h>

#include <linux/timecounter.h>



#define PTP_CLOCK_NAME_LEN	32

/**

 * struct ptp_clock_request - request PTP clock event

 *
@@ -134,7 +136,7 @@ struct ptp_system_timestamp { 


struct ptp_clock_info {

	struct module *owner;

	char name[16];

	char name[PTP_CLOCK_NAME_LEN];

	s32 max_adj;

	int n_alarm;

	int n_ext_ts;