[very-RFC 2/8] TSN: Add the standard formerly known as AVB to the kernel

Henrik Austad
2016-06-11T23:01:41Z

TSN provides a mechanism to create reliable, jitter-free, low latency
guaranteed bandwidth links over a local network. It does this by
reserving a path through the network. Support for TSN must be found in
both the NIC as well as in the network itself.

This adds required hooks into netdev_ops so that the core TSN driver can
use this when configuring a new NIC or setting up a new link.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Henrik Austad <henrik@austad.us>
---
include/linux/netdevice.h | 32 ++++++++++++++++++++++++++++++++
net/Kconfig | 1 +
net/tsn/Kconfig | 32 ++++++++++++++++++++++++++++++++
3 files changed, 65 insertions(+)
create mode 100644 net/tsn/Kconfig

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f45929c..de025eb 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -109,6 +109,13 @@ enum netdev_tx {
};
typedef enum netdev_tx netdev_tx_t;

+#if IS_ENABLED(CONFIG_TSN)
+enum sr_class {
+ SR_CLASS_A = 1,
+ SR_CLASS_B = 2,
+};
+#endif
+
/*
* Current order: NETDEV_TX_MASK > NET_XMIT_MASK >= 0 is significant;
* hard_start_xmit() return < NET_XMIT_MASK means skb was consumed.
@@ -902,6 +909,22 @@ struct tc_to_netdev {
*
* void (*ndo_poll_controller)(struct net_device *dev);
*
+ * TSN functions (if CONFIG_TSN)
+ *
+ * int (*ndo_tsn_capable)(struct net_device *dev);
+ * If a particular device is capable of sustaining TSN traffic
+ * provided current configuration
+ * int (*ndo_tsn_link_configure)(struct net_device *dev,
+ * enum sr_class class,
+ * u16 framesize,
+ * u16 vid);
+ * - When a new TSN link is either added or removed, this is called to
+ * update the bandwidth for the particular stream-class
+ * - The framesize is the size of the _entire_ frame, not just the
+ * payload since the full size is required to allocate bandwidth through
+ * the credit based shaper in the NIC
+ * - the vlan_id is the configured vlan for TSN in this session.
+ *
* SR-IOV management functions.
* int (*ndo_set_vf_mac)(struct net_device *dev, int vf, u8* mac);
* int (*ndo_set_vf_vlan)(struct net_device *dev, int vf, u16 vlan, u8 qos);
@@ -1148,6 +1171,15 @@ struct net_device_ops {
#ifdef CONFIG_NET_RX_BUSY_POLL
int (*ndo_busy_poll)(struct napi_struct *dev);
#endif
+
+#if IS_ENABLED(CONFIG_TSN)
+ int (*ndo_tsn_capable)(struct net_device *dev);
+ int (*ndo_tsn_link_configure)(struct net_device *dev,
+ enum sr_class class,
+ u16 framesize,
+ u16 vid);
+#endif /* CONFIG_TSN */
+
int (*ndo_set_vf_mac)(struct net_device *dev,
int queue, u8 *mac);
int (*ndo_set_vf_vlan)(struct net_device *dev,
diff --git a/net/Kconfig b/net/Kconfig
index ff40562..fa9f691 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -215,6 +215,7 @@ source "net/802/Kconfig"
source "net/bridge/Kconfig"
source "net/dsa/Kconfig"
source "net/8021q/Kconfig"
+source "net/tsn/Kconfig"
source "net/decnet/Kconfig"
source "net/llc/Kconfig"
source "net/ipx/Kconfig"
diff --git a/net/tsn/Kconfig b/net/tsn/Kconfig
new file mode 100644
index 0000000..1fc3c1d
--- /dev/null
+++ b/net/tsn/Kconfig
@@ -0,0 +1,32 @@
+#
+# Configuration for 802.1 Time Sensitive Networking (TSN)
+#
+
+config TSN
+ tristate "802.1 TSN Support"
+ depends on VLAN_8021Q && PTP_1588_CLOCK && CONFIGFS_FS
+ ---help---
+ Select this if you want to enable TSN on capable interfaces.
+
+ TSN allows you to set up deterministic links on your LAN (only
+ L2 is currently supported). Once loaded, the driver will probe
+ all available interfaces if they are capable of supporting TSN
+ links.
+
+ Once loaded, a directory in configfs called tsn/ will expose
+ the capable NICs and allow userspace to create
+ links. Userspace must provide us with a StreamID as well as
+ reserving bandwidth through the network and once this is done,
+ a new link can be created by issuing a mkdir() in configfs and
+ updating the attributes for the new link.
+
+ TSN itself does not produce nor consume data, it is dependent
+ upon 'shims' doing this, which can be virtually anything. ALSA
+ is a good candidate.
+
+ For more information, refer to the TSN-documentation in the
+ kernel documentation repository.
+
+ The resulting module will be called 'tsn'
+
+ If unsure, say N.
--
2.7.4