net: hsr: add offloading support

Add support for offloading of HSR/PRP (IEC 62439-3) tag insertion
tag removal, duplicate generation and forwarding.

For HSR, insertion involves the switch adding a 6 byte HSR header after
the 14 byte Ethernet header. For PRP it adds a 6 byte trailer.

Tag removal involves automatically stripping the HSR/PRP header/trailer
in the switch. This is possible when the switch also performs auto
deduplication using the HSR/PRP header/trailer (making it no longer
required).

Forwarding involves automatically forwarding between redundant ports in
an HSR. This is crucial because delay is accumulated as a frame passes
through each node in the ring.

Duplication involves the switch automatically sending a single frame
from the CPU port to both redundant ports. This is required because the
inserted HSR/PRP header/trailer must contain the same sequence number
on the frames sent out both redundant ports.

Export is_hsr_master so DSA can tell them apart from other devices in
dsa_slave_changeupper.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 0 deletions

diff --git a/include/linux/if_hsr.h b/include/linux/if_hsr.h
new file mode 100644
index 000000000000..38bbc537d4e4
--- /dev/null
+++ b/include/linux/if_hsr.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_IF_HSR_H_
+#define _LINUX_IF_HSR_H_
+
+/* used to differentiate various protocols */
+enum hsr_version {
+	HSR_V0 = 0,
+	HSR_V1,
+	PRP_V1,
+};
+
+#if IS_ENABLED(CONFIG_HSR)
+extern bool is_hsr_master(struct net_device *dev);
+extern int hsr_get_version(struct net_device *dev, enum hsr_version *ver);
+#else
+static inline bool is_hsr_master(struct net_device *dev)
+{
+	return false;
+}
+static inline int hsr_get_version(struct net_device *dev,
+				  enum hsr_version *ver)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_HSR */
+
+#endif /*_LINUX_IF_HSR_H_*/