ptp: track available ptp vclocks information

Track available ptp vclocks information. Record index values
of available ptp vclocks during registering and unregistering.

This is preparation for supporting ptp vclocks info query
through ethtool.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/ptp/ptp_clock.c

@@ -196,6 +196,7 @@ 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);
@@ -238,9 +239,17 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 	    strcmp(parent->class->name, "ptp") == 0)
 		ptp->is_virtual_clock = true;
 
-	if (!ptp->is_virtual_clock)
+	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;
@@ -285,6 +294,8 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
 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:
@@ -309,6 +320,8 @@ int ptp_clock_unregister(struct ptp_clock *ptp)
 	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);

drivers/ptp/ptp_private.h

@@ -49,6 +49,7 @@ struct ptp_clock {
 	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;
 };

drivers/ptp/ptp_sysfs.c

@@ -213,6 +213,9 @@ static ssize_t n_vclocks_store(struct device *dev,
 			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);
 		}
@@ -223,6 +226,9 @@ static ssize_t n_vclocks_store(struct device *dev,
 		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)
@@ -256,6 +262,9 @@ static ssize_t max_vclocks_store(struct device *dev,
 				 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)
@@ -267,16 +276,29 @@ static ssize_t max_vclocks_store(struct device *dev,
 	if (mutex_lock_interruptible(&ptp->n_vclocks_mux))
 		return -ERESTARTSYS;
 
-	if (max < ptp->n_vclocks) {
-		mutex_unlock(&ptp->n_vclocks_mux);
-		return -EINVAL;
+	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);