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yangbolu1991davem330
yangbolu1991
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davem330
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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: Yangbo Lu <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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‎drivers/ptp/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33
# Makefile for PTP 1588 clock support.
44
#
55

6-
ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o
6+
ptp-y := ptp_clock.o ptp_chardev.o ptp_sysfs.o ptp_vclock.o
77
ptp_kvm-$(CONFIG_X86) := ptp_kvm_x86.o ptp_kvm_common.o
88
ptp_kvm-$(CONFIG_HAVE_ARM_SMCCC) := ptp_kvm_arm.o ptp_kvm_common.o
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obj-$(CONFIG_PTP_1588_CLOCK) += ptp.o

‎drivers/ptp/ptp_private.h

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -48,6 +48,19 @@ struct ptp_clock {
4848
struct kthread_delayed_work aux_work;
4949
};
5050

51+
#define info_to_vclock(d) container_of((d), struct ptp_vclock, info)
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#define cc_to_vclock(d) container_of((d), struct ptp_vclock, cc)
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#define dw_to_vclock(d) container_of((d), struct ptp_vclock, refresh_work)
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struct ptp_vclock {
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struct ptp_clock *pclock;
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struct ptp_clock_info info;
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struct ptp_clock *clock;
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struct cyclecounter cc;
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struct timecounter tc;
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spinlock_t lock; /* protects tc/cc */
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};
63+
5164
/*
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* The function queue_cnt() is safe for readers to call without
5366
* holding q->lock. Readers use this function to verify that the queue
@@ -89,4 +102,6 @@ extern const struct attribute_group *ptp_groups[];
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int ptp_populate_pin_groups(struct ptp_clock *ptp);
90103
void ptp_cleanup_pin_groups(struct ptp_clock *ptp);
91104

105+
struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock);
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void ptp_vclock_unregister(struct ptp_vclock *vclock);
92107
#endif

‎drivers/ptp/ptp_vclock.c

Lines changed: 150 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,150 @@
1+
// 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
6+
*/
7+
#include <linux/slab.h>
8+
#include "ptp_private.h"
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#define PTP_VCLOCK_CC_SHIFT 31
11+
#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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static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
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{
18+
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);
26+
timecounter_read(&vclock->tc);
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vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;
28+
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_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 long ptp_vclock_refresh(struct ptp_clock_info *ptp)
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{
76+
struct ptp_vclock *vclock = info_to_vclock(ptp);
77+
struct timespec64 ts;
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ptp_vclock_gettime(&vclock->info, &ts);
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return PTP_VCLOCK_REFRESH_INTERVAL;
82+
}
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static const struct ptp_clock_info ptp_vclock_info = {
85+
.owner = THIS_MODULE,
86+
.name = "ptp virtual clock",
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/* The maximum ppb value that long scaled_ppm can support */
88+
.max_adj = 32767999,
89+
.adjfine = ptp_vclock_adjfine,
90+
.adjtime = ptp_vclock_adjtime,
91+
.gettime64 = ptp_vclock_gettime,
92+
.settime64 = ptp_vclock_settime,
93+
.do_aux_work = ptp_vclock_refresh,
94+
};
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96+
static u64 ptp_vclock_read(const struct cyclecounter *cc)
97+
{
98+
struct ptp_vclock *vclock = cc_to_vclock(cc);
99+
struct ptp_clock *ptp = vclock->pclock;
100+
struct timespec64 ts = {};
101+
102+
if (ptp->info->gettimex64)
103+
ptp->info->gettimex64(ptp->info, &ts, NULL);
104+
else
105+
ptp->info->gettime64(ptp->info, &ts);
106+
107+
return timespec64_to_ns(&ts);
108+
}
109+
110+
static const struct cyclecounter ptp_vclock_cc = {
111+
.read = ptp_vclock_read,
112+
.mask = CYCLECOUNTER_MASK(32),
113+
.mult = PTP_VCLOCK_CC_MULT,
114+
.shift = PTP_VCLOCK_CC_SHIFT,
115+
};
116+
117+
struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
118+
{
119+
struct ptp_vclock *vclock;
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121+
vclock = kzalloc(sizeof(*vclock), GFP_KERNEL);
122+
if (!vclock)
123+
return NULL;
124+
125+
vclock->pclock = pclock;
126+
vclock->info = ptp_vclock_info;
127+
vclock->cc = ptp_vclock_cc;
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129+
snprintf(vclock->info.name, PTP_CLOCK_NAME_LEN, "ptp%d_virt",
130+
pclock->index);
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132+
spin_lock_init(&vclock->lock);
133+
134+
vclock->clock = ptp_clock_register(&vclock->info, &pclock->dev);
135+
if (IS_ERR_OR_NULL(vclock->clock)) {
136+
kfree(vclock);
137+
return NULL;
138+
}
139+
140+
timecounter_init(&vclock->tc, &vclock->cc, 0);
141+
ptp_schedule_worker(vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);
142+
143+
return vclock;
144+
}
145+
146+
void ptp_vclock_unregister(struct ptp_vclock *vclock)
147+
{
148+
ptp_clock_unregister(vclock->clock);
149+
kfree(vclock);
150+
}

‎include/linux/ptp_clock_kernel.h

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,9 @@
1111
#include <linux/device.h>
1212
#include <linux/pps_kernel.h>
1313
#include <linux/ptp_clock.h>
14+
#include <linux/timecounter.h>
1415

16+
#define PTP_CLOCK_NAME_LEN 32
1517
/**
1618
* struct ptp_clock_request - request PTP clock event
1719
*
@@ -134,7 +136,7 @@ struct ptp_system_timestamp {
134136

135137
struct ptp_clock_info {
136138
struct module *owner;
137-
char name[16];
139+
char name[PTP_CLOCK_NAME_LEN];
138140
s32 max_adj;
139141
int n_alarm;
140142
int n_ext_ts;

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