Time stamping on network packets may happen either in the MAC or in
the PHY, but not both. In preparation for making the choice
selectable, expose both the current and available layers via sysfs.
In accordance with the kernel implementation as it stands, the current
layer will always read as "phy" when a PHY time stamping device is
present. Future patches will allow changing the current layer
administratively.
Signed-off-by: Richard Cochran <[email protected]>
---
.../ABI/testing/sysfs-class-net-timestamping | 17 ++++++
drivers/net/phy/phy_device.c | 2 +
include/linux/netdevice.h | 10 ++++
net/core/net-sysfs.c | 60 +++++++++++++++++++
4 files changed, 89 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-net-timestamping
diff --git a/Documentation/ABI/testing/sysfs-class-net-timestamping b/Documentation/ABI/testing/sysfs-class-net-timestamping
new file mode 100644
index 000000000000..529c3a6eb607
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-net-timestamping
@@ -0,0 +1,17 @@
+What: /sys/class/net/<iface>/available_timestamping_providers
+Date: January 2022
+Contact: Richard Cochran <[email protected]>
+Description:
+ Enumerates the available providers for SO_TIMESTAMPING.
+ The possible values are:
+ - "mac" The MAC provides time stamping.
+ - "phy" The PHY or MII device provides time stamping.
+
+What: /sys/class/net/<iface>/current_timestamping_provider
+Date: January 2022
+Contact: Richard Cochran <[email protected]>
+Description:
+ Show the current SO_TIMESTAMPING provider.
+ The possible values are:
+ - "mac" The MAC provides time stamping.
+ - "phy" The PHY or MII device provides time stamping.
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 74d8e1dc125f..5538ee27e865 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1415,6 +1415,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
phydev->phy_link_change = phy_link_change;
if (dev) {
+ dev->selected_timestamping_layer = PHY_TIMESTAMPING;
phydev->attached_dev = dev;
dev->phydev = phydev;
@@ -1727,6 +1728,7 @@ void phy_detach(struct phy_device *phydev)
phy_suspend(phydev);
if (dev) {
+ dev->selected_timestamping_layer = MAC_TIMESTAMPING;
phydev->attached_dev->phydev = NULL;
phydev->attached_dev = NULL;
}
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2684bdb6defa..b44ae00df3a8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1687,6 +1687,11 @@ enum netdev_ml_priv_type {
ML_PRIV_CAN,
};
+enum timestamping_layer {
+ MAC_TIMESTAMPING,
+ PHY_TIMESTAMPING,
+};
+
/**
* struct net_device - The DEVICE structure.
*
@@ -1927,6 +1932,9 @@ enum netdev_ml_priv_type {
*
* @threaded: napi threaded mode is enabled
*
+ * @selected_timestamping_layer: Tracks whether the MAC or the PHY
+ * performs packet time stamping.
+ *
* @net_notifier_list: List of per-net netdev notifier block
* that follow this device when it is moved
* to another network namespace.
@@ -2263,6 +2271,8 @@ struct net_device {
unsigned wol_enabled:1;
unsigned threaded:1;
+ enum timestamping_layer selected_timestamping_layer;
+
struct list_head net_notifier_list;
#if IS_ENABLED(CONFIG_MACSEC)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 53ea262ecafd..4ff7ef417c38 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -618,6 +618,64 @@ static ssize_t threaded_store(struct device *dev,
}
static DEVICE_ATTR_RW(threaded);
+static ssize_t available_timestamping_providers_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct ethtool_ops *ops;
+ struct net_device *netdev;
+ struct phy_device *phydev;
+ int ret = 0;
+
+ netdev = to_net_dev(dev);
+ phydev = netdev->phydev;
+ ops = netdev->ethtool_ops;
+
+ if (!rtnl_trylock())
+ return restart_syscall();
+
+ ret += sprintf(buf, "%s\n", "mac");
+ buf += 4;
+
+ if (phy_has_tsinfo(phydev)) {
+ ret += sprintf(buf, "%s\n", "phy");
+ buf += 4;
+ }
+
+ rtnl_unlock();
+
+ return ret;
+}
+static DEVICE_ATTR_RO(available_timestamping_providers);
+
+static ssize_t current_timestamping_provider_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct ethtool_ops *ops;
+ struct net_device *netdev;
+ struct phy_device *phydev;
+ int ret;
+
+ netdev = to_net_dev(dev);
+ phydev = netdev->phydev;
+ ops = netdev->ethtool_ops;
+
+ if (!rtnl_trylock())
+ return restart_syscall();
+
+ if (phy_has_tsinfo(phydev)) {
+ ret = sprintf(buf, "%s\n", "phy");
+ } else {
+ ret = sprintf(buf, "%s\n", "mac");
+ }
+
+ rtnl_unlock();
+
+ return ret;
+}
+static DEVICE_ATTR_RO(current_timestamping_provider);
+
static struct attribute *net_class_attrs[] __ro_after_init = {
&dev_attr_netdev_group.attr,
&dev_attr_type.attr,
@@ -651,6 +709,8 @@ static struct attribute *net_class_attrs[] __ro_after_init = {
&dev_attr_carrier_up_count.attr,
&dev_attr_carrier_down_count.attr,
&dev_attr_threaded.attr,
+ &dev_attr_available_timestamping_providers.attr,
+ &dev_attr_current_timestamping_provider.attr,
NULL,
};
ATTRIBUTE_GROUPS(net_class);
--
2.20.1
On Mon, Jan 03, 2022 at 03:25:53PM -0800, Richard Cochran wrote:
> Time stamping on network packets may happen either in the MAC or in
> the PHY, but not both. In preparation for making the choice
> selectable, expose both the current and available layers via sysfs.
>
> In accordance with the kernel implementation as it stands, the current
> layer will always read as "phy" when a PHY time stamping device is
> present. Future patches will allow changing the current layer
> administratively.
>
> Signed-off-by: Richard Cochran <[email protected]>
Did you mean to introduce "selected_timestamping_layer" in this patch -
it appears to be a write only variable.
As it stands, it gets set to indicate PHY mode just by a network driver
binding to a PHY. If this gets used based on that decision to direct
where get_ts_info() goes, then this will break mvpp2 PTP.
I suggest that the introduction of "selected_timestamping_layer" is
moved to the patch where it's actually used for a better review.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!