ptp: support ptp physical/virtual clocks conversion

Support ptp physical/virtual clocks conversion via sysfs.
There will be a new attribute n_vclocks under ptp physical
clock sysfs.

- In default, the value is 0 meaning only ptp physical clock
  is in use.
- Setting the value can create corresponding number of ptp
  virtual clocks to use. But current physical clock is guaranteed
  to stay free running.
- Setting the value back to 0 can delete virtual clocks and back
  use physical clock again.

Another new attribute max_vclocks control the maximum number of
ptp vclocks.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/ABI/testing/sysfs-ptp b/Documentation/ABI/testing/sysfs-ptp
index 2363ad8..d378f57 100644 (file)
--- a/Documentation/ABI/testing/sysfs-ptp
+++ b/Documentation/ABI/testing/sysfs-ptp
@@ -33,6 +33,13 @@ Description:
                frequency adjustment value (a positive integer) in
                parts per billion.
 
+What:          /sys/class/ptp/ptpN/max_vclocks
+Date:          May 2021
+Contact:       Yangbo Lu <yangbo.lu@nxp.com>
+Description:
+               This file contains the maximum number of ptp vclocks.
+               Write integer to re-configure it.
+
 What:          /sys/class/ptp/ptpN/n_alarms
 Date:          September 2010
 Contact:       Richard Cochran <richardcochran@gmail.com>
@@ -61,6 +68,19 @@ Description:
                This file contains the number of programmable pins
                offered by the PTP hardware clock.
 
+What:          /sys/class/ptp/ptpN/n_vclocks
+Date:          May 2021
+Contact:       Yangbo Lu <yangbo.lu@nxp.com>
+Description:
+               This file contains the number of virtual PTP clocks in
+               use.  By default, the value is 0 meaning that only the
+               physical clock is in use.  Setting the value creates
+               the corresponding number of virtual clocks and causes
+               the physical clock to become free running.  Setting the
+               value back to 0 deletes the virtual clocks and
+               switches the physical clock back to normal, adjustable
+               operation.
+
 What:          /sys/class/ptp/ptpN/pins
 Date:          March 2014
 Contact:       Richard Cochran <richardcochran@gmail.com>

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index a23a37a..7334f47 100644 (file)
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -76,6 +76,11 @@ 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 +102,11 @@ 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 +171,7 @@ 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);
 }
@@ -208,6 +219,7 @@ 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 +233,14 @@ 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;
+
        err = ptp_populate_pin_groups(ptp);
        if (err)
                goto no_pin_groups;
@@ -270,6 +290,7 @@ no_pin_groups:
 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);
@@ -280,6 +301,11 @@ 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);
 

diff --git a/drivers/ptp/ptp_private.h b/drivers/ptp/ptp_private.h
index 853b79b..87cb559 100644 (file)
--- 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 +47,10 @@ 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;
+       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)
@@ -74,6 +79,22 @@ 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;
+}
+
 /*
  * see ptp_chardev.c
  */

diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index be076a9..0b05041 100644 (file)
--- 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 +149,137 @@ 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;
+
+                       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);
+       }
+
+       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);
+       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) {
+               mutex_unlock(&ptp->n_vclocks_mux);
+               return -EINVAL;
+       }
+
+       ptp->max_vclocks = max;
+
+       mutex_unlock(&ptp->n_vclocks_mux);
+
+       return count;
+}
+static DEVICE_ATTR_RW(max_vclocks);
+
 static struct attribute *ptp_attrs[] = {
        &dev_attr_clock_name.attr,
 
@@ -162,6 +294,8 @@ 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 +317,10 @@ 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;