Merge branch 'ptp-virtual-clocks-and-timestamping'

Yangbo Lu says:

====================
ptp: support virtual clocks and timestamping

Current PTP driver exposes one PTP device to user which binds network
interface/interfaces to provide timestamping. Actually we have a way
utilizing timecounter/cyclecounter to virtualize any number of PTP
clocks based on a same free running physical clock for using.
The purpose of having multiple PTP virtual clocks is for user space
to directly/easily use them for multiple domains synchronization.

user
space:     ^                                  ^
           | SO_TIMESTAMPING new flag:        | Packets with
           | SOF_TIMESTAMPING_BIND_PHC        | TX/RX HW timestamps
           v                                  v
         +--------------------------------------------+
sock:    |     sock (new member sk_bind_phc)          |
         +--------------------------------------------+
           ^                                  ^
           | ethtool_get_phc_vclocks          | Convert HW timestamps
           |                                  | to sk_bind_phc
           v                                  v
         +--------------+--------------+--------------+
vclock:  | ptp1         | ptp2         | ptpN         |
         +--------------+--------------+--------------+
pclock:  |             ptp0 free running              |
         +--------------------------------------------+

The block diagram may explain how it works. Besides the PTP virtual
clocks, the packet HW timestamp converting to the bound PHC is also
done in sock driver. For user space, PTP virtual clocks can be
created via sysfs, and extended SO_TIMESTAMPING API (new flag
SOF_TIMESTAMPING_BIND_PHC) can be used to bind one PTP virtual clock
for timestamping.

The test tool timestamping.c (together with linuxptp phc_ctl tool) can
be used to verify:

  # echo 4 > /sys/class/ptp/ptp0/n_vclocks
  [  129.399472] ptp ptp0: new virtual clock ptp2
  [  129.404234] ptp ptp0: new virtual clock ptp3
  [  129.409532] ptp ptp0: new virtual clock ptp4
  [  129.413942] ptp ptp0: new virtual clock ptp5
  [  129.418257] ptp ptp0: guarantee physical clock free running
  #
  # phc_ctl /dev/ptp2 set 10000
  # phc_ctl /dev/ptp3 set 20000
  #
  # timestamping eno0 2 SOF_TIMESTAMPING_TX_HARDWARE SOF_TIMESTAMPING_RAW_HARDWARE SOF_TIMESTAMPING_BIND_PHC
  # timestamping eno0 2 SOF_TIMESTAMPING_RX_HARDWARE SOF_TIMESTAMPING_RAW_HARDWARE SOF_TIMESTAMPING_BIND_PHC
  # timestamping eno0 3 SOF_TIMESTAMPING_TX_HARDWARE SOF_TIMESTAMPING_RAW_HARDWARE SOF_TIMESTAMPING_BIND_PHC
  # timestamping eno0 3 SOF_TIMESTAMPING_RX_HARDWARE SOF_TIMESTAMPING_RAW_HARDWARE SOF_TIMESTAMPING_BIND_PHC

Changes for v2:
	- Converted to num_vclocks for creating virtual clocks.
	- Guranteed physical clock free running when using virtual
	  clocks.
	- Fixed build warning.
	- Updated copyright.
Changes for v3:
	- Supported PTP virtual clock in default in PTP driver.
	- Protected concurrency of ptp->num_vclocks accessing.
	- Supported PHC vclocks query via ethtool.
	- Extended SO_TIMESTAMPING API for PHC binding.
	- Converted HW timestamps to PHC bound, instead of previous
	  binding domain value to PHC idea.
	- Other minor fixes.
Changes for v4:
	- Used do_aux_work callback for vclock refreshing instead.
	- Used unsigned int for vclocks number, and max_vclocks
	  for limitiation.
	- Fixed mutex locking.
	- Dynamically allocated memory for vclock index storage.
	- Removed ethtool ioctl command for vclocks getting.
	- Updated doc for ethtool phc vclocks get.
	- Converted to mptcp_setsockopt_sol_socket_timestamping().
	- Passed so_timestamping for sock_set_timestamping.
	- Fixed checkpatch/build.
	- Other minor fixed.
Changes for v5:
	- Fixed checkpatch/build/bug reported by test robot.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 460 insertions, 2 deletions

diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile
index 8673d1743faa..28a6fe342d3e 100644
--- a/drivers/ptp/Makefile
+++ b/drivers/ptp/Makefile
@@ -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
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index a23a37a4d5dc..f012fa581cf4 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -24,10 +24,11 @@
 #define PTP_PPS_EVENT PPS_CAPTUREASSERT
 #define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
 
+struct class *ptp_class;
+
 /* private globals */
 
 static dev_t ptp_devt;
-static struct class *ptp_class;
 
 static DEFINE_IDA(ptp_clocks_map);
 
@@ -76,6 +77,11 @@ static int ptp_clock_settime(struct posix_clock *pc, const struct timespec64 *tp
 {
 	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 
+	if (ptp_vclock_in_use(ptp)) {
+		pr_err("ptp: virtual clock in use\n");
+		return -EBUSY;
+	}
+
 	return  ptp->info->settime64(ptp->info, tp);
 }
 
@@ -97,6 +103,11 @@ static int ptp_clock_adjtime(struct posix_clock *pc, struct __kernel_timex *tx)
 	struct ptp_clock_info *ops;
 	int err = -EOPNOTSUPP;
 
+	if (ptp_vclock_in_use(ptp)) {
+		pr_err("ptp: virtual clock in use\n");
+		return -EBUSY;
+	}
+
 	ops = ptp->info;
 
 	if (tx->modes & ADJ_SETOFFSET) {
@@ -161,6 +172,7 @@ static void ptp_clock_release(struct device *dev)
 	ptp_cleanup_pin_groups(ptp);
 	mutex_destroy(&ptp->tsevq_mux);
 	mutex_destroy(&ptp->pincfg_mux);
+	mutex_destroy(&ptp->n_vclocks_mux);
 	ida_simple_remove(&ptp_clocks_map, ptp->index);
 	kfree(ptp);
 }
@@ -185,6 +197,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 {
 	struct ptp_clock *ptp;
 	int err = 0, index, major = MAJOR(ptp_devt);
+	size_t size;
 
 	if (info->n_alarm > PTP_MAX_ALARMS)
 		return ERR_PTR(-EINVAL);
@@ -208,6 +221,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	spin_lock_init(&ptp->tsevq.lock);
 	mutex_init(&ptp->tsevq_mux);
 	mutex_init(&ptp->pincfg_mux);
+	mutex_init(&ptp->n_vclocks_mux);
 	init_waitqueue_head(&ptp->tsev_wq);
 
 	if (ptp->info->do_aux_work) {
@@ -221,6 +235,22 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 		ptp->pps_source->lookup_cookie = ptp;
 	}
 
+	/* PTP virtual clock is being registered under physical clock */
+	if (parent->class && parent->class->name &&
+	    strcmp(parent->class->name, "ptp") == 0)
+		ptp->is_virtual_clock = true;
+
+	if (!ptp->is_virtual_clock) {
+		ptp->max_vclocks = PTP_DEFAULT_MAX_VCLOCKS;
+
+		size = sizeof(int) * ptp->max_vclocks;
+		ptp->vclock_index = kzalloc(size, GFP_KERNEL);
+		if (!ptp->vclock_index) {
+			err = -ENOMEM;
+			goto no_mem_for_vclocks;
+		}
+	}
+
 	err = ptp_populate_pin_groups(ptp);
 	if (err)
 		goto no_pin_groups;
@@ -265,11 +295,14 @@ no_clock:
 no_pps:
 	ptp_cleanup_pin_groups(ptp);
 no_pin_groups:
+	kfree(ptp->vclock_index);
+no_mem_for_vclocks:
 	if (ptp->kworker)
 		kthread_destroy_worker(ptp->kworker);
 kworker_err:
 	mutex_destroy(&ptp->tsevq_mux);
 	mutex_destroy(&ptp->pincfg_mux);
+	mutex_destroy(&ptp->n_vclocks_mux);
 	ida_simple_remove(&ptp_clocks_map, index);
 no_slot:
 	kfree(ptp);
@@ -280,9 +313,16 @@ EXPORT_SYMBOL(ptp_clock_register);
 
 int ptp_clock_unregister(struct ptp_clock *ptp)
 {
+	if (ptp_vclock_in_use(ptp)) {
+		pr_err("ptp: virtual clock in use\n");
+		return -EBUSY;
+	}
+
 	ptp->defunct = 1;
 	wake_up_interruptible(&ptp->tsev_wq);
 
+	kfree(ptp->vclock_index);
+
 	if (ptp->kworker) {
 		kthread_cancel_delayed_work_sync(&ptp->aux_work);
 		kthread_destroy_worker(ptp->kworker);
diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 6b97155148f1..dba6be477067 100644
--- a/drivers/ptp/ptp_private.h
+++ b/drivers/ptp/ptp_private.h
@@ -18,6 +18,7 @@
 
 #define PTP_MAX_TIMESTAMPS 128
 #define PTP_BUF_TIMESTAMPS 30
+#define PTP_DEFAULT_MAX_VCLOCKS 20
 
 struct timestamp_event_queue {
 	struct ptp_extts_event buf[PTP_MAX_TIMESTAMPS];
@@ -46,6 +47,24 @@ struct ptp_clock {
 	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;
+};
+
+#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 */
 };
 
 /*
@@ -61,6 +80,24 @@ static inline int queue_cnt(struct timestamp_event_queue *q)
 	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;
+
+	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
+		return true;
+
+	if (!ptp->is_virtual_clock && ptp->n_vclocks)
+		in_use = true;
+
+	mutex_unlock(&ptp->n_vclocks_mux);
+
+	return in_use;
+}
+
+extern struct class *ptp_class;
+
 /*
  * see ptp_chardev.c
  */
@@ -89,4 +126,6 @@ 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
diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index be076a91e20e..6a36590ca77a 100644
--- a/drivers/ptp/ptp_sysfs.c
+++ b/drivers/ptp/ptp_sysfs.c
@@ -3,6 +3,7 @@
  * PTP 1588 clock support - sysfs interface.
  *
  * Copyright (C) 2010 OMICRON electronics GmbH
+ * Copyright 2021 NXP
  */
 #include <linux/capability.h>
 #include <linux/slab.h>
@@ -148,6 +149,159 @@ out:
 }
 static DEVICE_ATTR(pps_enable, 0220, NULL, pps_enable_store);
 
+static int unregister_vclock(struct device *dev, void *data)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+	struct ptp_clock_info *info = ptp->info;
+	struct ptp_vclock *vclock;
+	u8 *num = data;
+
+	vclock = info_to_vclock(info);
+	dev_info(dev->parent, "delete virtual clock ptp%d\n",
+		 vclock->clock->index);
+
+	ptp_vclock_unregister(vclock);
+	(*num)--;
+
+	/* For break. Not error. */
+	if (*num == 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static ssize_t n_vclocks_show(struct device *dev,
+			      struct device_attribute *attr, char *page)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+	ssize_t size;
+
+	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
+		return -ERESTARTSYS;
+
+	size = snprintf(page, PAGE_SIZE - 1, "%d\n", ptp->n_vclocks);
+
+	mutex_unlock(&ptp->n_vclocks_mux);
+
+	return size;
+}
+
+static ssize_t n_vclocks_store(struct device *dev,
+			       struct device_attribute *attr,
+			       const char *buf, size_t count)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+	struct ptp_vclock *vclock;
+	int err = -EINVAL;
+	u32 num, i;
+
+	if (kstrtou32(buf, 0, &num))
+		return err;
+
+	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
+		return -ERESTARTSYS;
+
+	if (num > ptp->max_vclocks) {
+		dev_err(dev, "max value is %d\n", ptp->max_vclocks);
+		goto out;
+	}
+
+	/* Need to create more vclocks */
+	if (num > ptp->n_vclocks) {
+		for (i = 0; i < num - ptp->n_vclocks; i++) {
+			vclock = ptp_vclock_register(ptp);
+			if (!vclock)
+				goto out;
+
+			*(ptp->vclock_index + ptp->n_vclocks + i) =
+				vclock->clock->index;
+
+			dev_info(dev, "new virtual clock ptp%d\n",
+				 vclock->clock->index);
+		}
+	}
+
+	/* Need to delete vclocks */
+	if (num < ptp->n_vclocks) {
+		i = ptp->n_vclocks - num;
+		device_for_each_child_reverse(dev, &i,
+					      unregister_vclock);
+
+		for (i = 1; i <= ptp->n_vclocks - num; i++)
+			*(ptp->vclock_index + ptp->n_vclocks - i) = -1;
+	}
+
+	if (num == 0)
+		dev_info(dev, "only physical clock in use now\n");
+	else
+		dev_info(dev, "guarantee physical clock free running\n");
+
+	ptp->n_vclocks = num;
+	mutex_unlock(&ptp->n_vclocks_mux);
+
+	return count;
+out:
+	mutex_unlock(&ptp->n_vclocks_mux);
+	return err;
+}
+static DEVICE_ATTR_RW(n_vclocks);
+
+static ssize_t max_vclocks_show(struct device *dev,
+				struct device_attribute *attr, char *page)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+	ssize_t size;
+
+	size = snprintf(page, PAGE_SIZE - 1, "%d\n", ptp->max_vclocks);
+
+	return size;
+}
+
+static ssize_t max_vclocks_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct ptp_clock *ptp = dev_get_drvdata(dev);
+	unsigned int *vclock_index;
+	int err = -EINVAL;
+	size_t size;
+	u32 max;
+
+	if (kstrtou32(buf, 0, &max) || max == 0)
+		return -EINVAL;
+
+	if (max == ptp->max_vclocks)
+		return count;
+
+	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
+		return -ERESTARTSYS;
+
+	if (max < ptp->n_vclocks)
+		goto out;
+
+	size = sizeof(int) * max;
+	vclock_index = kzalloc(size, GFP_KERNEL);
+	if (!vclock_index) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	size = sizeof(int) * ptp->n_vclocks;
+	memcpy(vclock_index, ptp->vclock_index, size);
+
+	kfree(ptp->vclock_index);
+	ptp->vclock_index = vclock_index;
+	ptp->max_vclocks = max;
+
+	mutex_unlock(&ptp->n_vclocks_mux);
+
+	return count;
+out:
+	mutex_unlock(&ptp->n_vclocks_mux);
+	return err;
+}
+static DEVICE_ATTR_RW(max_vclocks);
+
 static struct attribute *ptp_attrs[] = {
 	&dev_attr_clock_name.attr,
 
@@ -162,6 +316,8 @@ static struct attribute *ptp_attrs[] = {
 	&dev_attr_fifo.attr,
 	&dev_attr_period.attr,
 	&dev_attr_pps_enable.attr,
+	&dev_attr_n_vclocks.attr,
+	&dev_attr_max_vclocks.attr,
 	NULL
 };
 
@@ -183,6 +339,10 @@ static umode_t ptp_is_attribute_visible(struct kobject *kobj,
 	} else if (attr == &dev_attr_pps_enable.attr) {
 		if (!info->pps)
 			mode = 0;
+	} else if (attr == &dev_attr_n_vclocks.attr ||
+		   attr == &dev_attr_max_vclocks.attr) {
+		if (ptp->is_virtual_clock)
+			mode = 0;
 	}
 
 	return mode;
diff --git a/drivers/ptp/ptp_vclock.c b/drivers/ptp/ptp_vclock.c
new file mode 100644
index 000000000000..e0f87c57749a
--- /dev/null
+++ b/drivers/ptp/ptp_vclock.c
@@ -0,0 +1,219 @@
+// 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);
+}
+
+int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
+{
+	char name[PTP_CLOCK_NAME_LEN] = "";
+	struct ptp_clock *ptp;
+	struct device *dev;
+	int num = 0;
+
+	if (pclock_index < 0)
+		return num;
+
+	snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", pclock_index);
+	dev = class_find_device_by_name(ptp_class, name);
+	if (!dev)
+		return num;
+
+	ptp = dev_get_drvdata(dev);
+
+	if (mutex_lock_interruptible(&ptp->n_vclocks_mux)) {
+		put_device(dev);
+		return num;
+	}
+
+	*vclock_index = kzalloc(sizeof(int) * ptp->n_vclocks, GFP_KERNEL);
+	if (!(*vclock_index))
+		goto out;
+
+	memcpy(*vclock_index, ptp->vclock_index, sizeof(int) * ptp->n_vclocks);
+	num = ptp->n_vclocks;
+out:
+	mutex_unlock(&ptp->n_vclocks_mux);
+	put_device(dev);
+	return num;
+}
+EXPORT_SYMBOL(ptp_get_vclocks_index);
+
+void ptp_convert_timestamp(struct skb_shared_hwtstamps *hwtstamps,
+			   int vclock_index)
+{
+	char name[PTP_CLOCK_NAME_LEN] = "";
+	struct ptp_vclock *vclock;
+	struct ptp_clock *ptp;
+	unsigned long flags;
+	struct device *dev;
+	u64 ns;
+
+	snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", vclock_index);
+	dev = class_find_device_by_name(ptp_class, name);
+	if (!dev)
+		return;
+
+	ptp = dev_get_drvdata(dev);
+	if (!ptp->is_virtual_clock) {
+		put_device(dev);
+		return;
+	}
+
+	vclock = info_to_vclock(ptp->info);
+
+	ns = ktime_to_ns(hwtstamps->hwtstamp);
+
+	spin_lock_irqsave(&vclock->lock, flags);
+	ns = timecounter_cyc2time(&vclock->tc, ns);
+	spin_unlock_irqrestore(&vclock->lock, flags);
+
+	put_device(dev);
+	hwtstamps->hwtstamp = ns_to_ktime(ns);
+}
+EXPORT_SYMBOL(ptp_convert_timestamp);