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>

1 files changed, 138 insertions, 0 deletions

diff --git a/drivers/ptp/ptp_sysfs.c b/drivers/ptp/ptp_sysfs.c
index be076a91e20e..0b05041783a5 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 +149,137 @@ 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;