[PATCH net-next v2 0/8] ethtool: Add support for frame preemption

[PATCH net-next v2 0/8] ethtool: Add support for frame preemption

[Vinicius Costa Gomes]

Changes from v1:
 - The minimum fragment size configuration was changed to be
   configured in bytes to be more future proof, in case the standard
   changes this (the previous definition was '(X + 1) * 64', X being
   [0..3]) (Michal Kubecek);
 - In taprio, frame preemption is now configured by traffic classes (was
   done by queues) (Jakub Kicinski, Vladimir Oltean);
 - Various netlink protocol validation improvements (Jakub Kicinski);
 - Dropped the IGC register dump for frame preemption registers, until a
   stardandized way of exposing that is agreed (Jakub Kicinski);

Changes from RFC v2:
 - Reorganised the offload enabling/disabling on the driver size;
 - Added a few igc fixes;

Changes from RFC v1:
 - The per-queue preemptible/express setting is moved to applicable
   qdiscs (Jakub Kicinski and others);
 - "min-frag-size" now follows the 802.3br specification more closely,
   it's expressed as X in '64(1 + X) + 4' (Joergen Andreasen);

Another point that should be noted is the addition of the
TC_SETUP_PREEMPT offload type, the idea behind this is to allow other
qdiscs (was thinking of mqprio) to also configure which traffic
classes should be marked as express/preemptible.

Original cover letter:

This is still an RFC because two main reasons, I want to confirm that
this approach (per-queue settings via qdiscs, device settings via
ethtool) looks good, even though there aren't much more options left ;-)
The other reason is that while testing this I found some weirdness
in the driver that I would need a bit more time to investigate.

(In case these patches are not enough to give an idea of how things
work, I can send the userspace patches, of course.)

The idea of this "hybrid" approach is that applications/users would do
the following steps to configure frame preemption:

$ tc qdisc replace dev $IFACE parent root handle 100 taprio \
      num_tc 3 \
      map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \
      queues 1@0 1@1 2@2 \
      base-time $BASE_TIME \
      sched-entry S 0f 10000000 \
      preempt 1110 \
      flags 0x2 

The "preempt" parameter is the only difference, it configures which
queues are marked as preemptible, in this example, queue 0 is marked
as "not preemptible", so it is express, the rest of the four queues
are preemptible.

The next step, of this example, would be to enable frame preemption in
the device, via ethtool, and set the minimum fragment size to 2:

$ sudo ./ethtool --set-frame-preemption $IFACE fp on min-frag-size 2

Cheers,

Vinicius Costa Gomes (8):
  ethtool: Add support for configuring frame preemption
  taprio: Add support for frame preemption offload
  igc: Set the RX packet buffer size for TSN mode
  igc: Only dump registers if configured to dump HW information
  igc: Avoid TX Hangs because long cycles
  igc: Add support for tuning frame preemption via ethtool
  igc: Add support for Frame Preemption offload
  igc: Separate TSN configurations that can be updated

 Documentation/networking/ethtool-netlink.rst |  38 +++++
 drivers/net/ethernet/intel/igc/igc.h         |  12 ++
 drivers/net/ethernet/intel/igc/igc_defines.h |   6 +
 drivers/net/ethernet/intel/igc/igc_dump.c    |   3 +
 drivers/net/ethernet/intel/igc/igc_ethtool.c |  53 ++++++
 drivers/net/ethernet/intel/igc/igc_main.c    |  31 +++-
 drivers/net/ethernet/intel/igc/igc_tsn.c     | 162 ++++++++++++++-----
 drivers/net/ethernet/intel/igc/igc_tsn.h     |   1 +
 include/linux/ethtool.h                      |  39 ++++-
 include/linux/netdevice.h                    |   1 +
 include/net/pkt_sched.h                      |   4 +
 include/uapi/linux/ethtool_netlink.h         |  17 ++
 include/uapi/linux/pkt_sched.h               |   1 +
 net/ethtool/Makefile                         |   2 +-
 net/ethtool/common.c                         |  10 ++
 net/ethtool/netlink.c                        |  19 +++
 net/ethtool/netlink.h                        |   4 +
 net/ethtool/preempt.c                        | 146 +++++++++++++++++
 net/sched/sch_taprio.c                       |  41 ++++-
 19 files changed, 539 insertions(+), 51 deletions(-)
 create mode 100644 net/ethtool/preempt.c

-- 
2.30.0

[PATCH net-next v2 1/8] ethtool: Add support for configuring frame preemption

[Vinicius Costa Gomes]

Frame preemption (described in IEEE 802.3br-2016) defines the concept
of preemptible and express queues. It allows traffic from express
queues to "interrupt" traffic from preemptible queues, which are
"resumed" after the express traffic has finished transmitting.

Frame preemption can only be used when both the local device and the
link partner support it.

Only parameters for enabling/disabling frame preemption and
configuring the minimum fragment size are included here. Expressing
which queues are marked as preemptible is left to mqprio/taprio, as
having that information there should be easier on the user.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 Documentation/networking/ethtool-netlink.rst |  38 +++++
 include/linux/ethtool.h                      |  39 ++++-
 include/uapi/linux/ethtool_netlink.h         |  17 +++
 net/ethtool/Makefile                         |   2 +-
 net/ethtool/common.c                         |  10 ++
 net/ethtool/netlink.c                        |  19 +++
 net/ethtool/netlink.h                        |   4 +
 net/ethtool/preempt.c                        | 146 +++++++++++++++++++
 8 files changed, 273 insertions(+), 2 deletions(-)
 create mode 100644 net/ethtool/preempt.c

diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 30b98245979f..fc71d11317c2 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -1279,6 +1279,44 @@ Kernel response contents:
 For UDP tunnel table empty ``ETHTOOL_A_TUNNEL_UDP_TABLE_TYPES`` indicates that
 the table contains static entries, hard-coded by the NIC.
 
+PREEMPT_GET
+===========
+
+Get information about frame preemption state.
+
+Request contents:
+
+  ====================================  ======  ==========================
+  ``ETHTOOL_A_CHANNELS_HEADER``         nested  request header
+  ====================================  ======  ==========================
+
+Kernel response contents:
+
+  =====================================  ======  ==========================
+  ``ETHTOOL_A_CHANNELS_HEADER``          nested  reply header
+  ``ETHTOOL_A_PREEMPT_ENABLED``          u8      frame preemption enabled
+  ``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE``    u32     Min additional frag size
+  =====================================  ======  ==========================
+
+``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE`` configures the minimum non-final
+fragment size that the receiver device supports.
+
+PREEMPT_SET
+============
+
+Sets frame preemption parameters.
+
+Request contents:
+
+  =====================================  ======  ==========================
+  ``ETHTOOL_A_CHANNELS_HEADER``          nested  reply header
+  ``ETHTOOL_A_PREEMPT_ENABLED``          u8      frame preemption enabled
+  ``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE``    u32     Min additional frag size
+  =====================================  ======  ==========================
+
+``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE`` configures the minimum non-final
+fragment size that the receiver device supports.
+
 Request translation
 ===================
 
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index e3da25b51ae4..f7692a348e9d 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -263,6 +263,22 @@ struct ethtool_pause_stats {
 	u64 rx_pause_frames;
 };
 
+/**
+ * struct ethtool_fp - Frame Preemption information
+ *
+ * @enabled: Enable frame preemption.
+
+ * @add_frag_size: Minimum size for additional (non-final) fragments
+ * in bytes, for the value defined in the IEEE 802.3-2018 standard see
+ * ethtool_frag_size_to_mult().
+ */
+struct ethtool_fp {
+	u8 enabled;
+	u32 add_frag_size;
+};
+
+struct netlink_ext_ack;
+
 /**
  * struct ethtool_ops - optional netdev operations
  * @supported_coalesce_params: supported types of interrupt coalescing.
@@ -406,6 +422,8 @@ struct ethtool_pause_stats {
  * @get_ethtool_phy_stats: Return extended statistics about the PHY device.
  *	This is only useful if the device maintains PHY statistics and
  *	cannot use the standard PHY library helpers.
+ * @get_preempt: Get the network device Frame Preemption parameters.
+ * @set_preempt: Set the network device Frame Preemption parameters.
  *
  * All operations are optional (i.e. the function pointer may be set
  * to %NULL) and callers must take this into account.  Callers must
@@ -504,6 +522,10 @@ struct ethtool_ops {
 				      struct ethtool_fecparam *);
 	int	(*set_fecparam)(struct net_device *,
 				      struct ethtool_fecparam *);
+	int	(*get_preempt)(struct net_device *,
+			       struct ethtool_fp *);
+	int	(*set_preempt)(struct net_device *, struct ethtool_fp *,
+			       struct netlink_ext_ack *);
 	void	(*get_ethtool_phy_stats)(struct net_device *,
 					 struct ethtool_stats *, u64 *);
 	int	(*get_phy_tunable)(struct net_device *,
@@ -533,7 +555,6 @@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev,
 				       const struct ethtool_link_ksettings *cmd,
 				       u32 *dev_speed, u8 *dev_duplex);
 
-struct netlink_ext_ack;
 struct phy_device;
 struct phy_tdr_config;
 
@@ -566,4 +587,20 @@ struct ethtool_phy_ops {
  */
 void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops);
 
+/**
+ * Convert from a Frame Preemption Additional Fragment size in bytes
+ * to a multiplier. The multiplier is defined as:
+ *	"A 2-bit integer value used to indicate the minimum size of
+ *	non-final fragments supported by the receiver on the given port
+ *	associated with the local System. This value is expressed in units
+ *	of 64 octets of additional fragment length."
+ *	Equivalent to `30.14.1.7 aMACMergeAddFragSize` from the IEEE 802.3-2018
+ *	standard.
+ *
+ * @frag_size: minimum non-final fragment size in bytes
+ *
+ * Returns the multiplier.
+ */
+u8 ethtool_frag_size_to_mult(u32 frag_size);
+
 #endif /* _LINUX_ETHTOOL_H */
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index e2bf36e6964b..bd7a722dc13a 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -42,6 +42,8 @@ enum {
 	ETHTOOL_MSG_CABLE_TEST_ACT,
 	ETHTOOL_MSG_CABLE_TEST_TDR_ACT,
 	ETHTOOL_MSG_TUNNEL_INFO_GET,
+	ETHTOOL_MSG_PREEMPT_GET,
+	ETHTOOL_MSG_PREEMPT_SET,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_USER_CNT,
@@ -80,6 +82,8 @@ enum {
 	ETHTOOL_MSG_CABLE_TEST_NTF,
 	ETHTOOL_MSG_CABLE_TEST_TDR_NTF,
 	ETHTOOL_MSG_TUNNEL_INFO_GET_REPLY,
+	ETHTOOL_MSG_PREEMPT_GET_REPLY,
+	ETHTOOL_MSG_PREEMPT_NTF,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,
@@ -628,6 +632,19 @@ enum {
 	ETHTOOL_A_TUNNEL_INFO_MAX = (__ETHTOOL_A_TUNNEL_INFO_CNT - 1)
 };
 
+/* FRAME PREEMPTION */
+
+enum {
+	ETHTOOL_A_PREEMPT_UNSPEC,
+	ETHTOOL_A_PREEMPT_HEADER,			/* nest - _A_HEADER_* */
+	ETHTOOL_A_PREEMPT_ENABLED,			/* u8 */
+	ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE,		/* u32 */
+
+	/* add new constants above here */
+	__ETHTOOL_A_PREEMPT_CNT,
+	ETHTOOL_A_PREEMPT_MAX = (__ETHTOOL_A_PREEMPT_CNT - 1)
+};
+
 /* generic netlink info */
 #define ETHTOOL_GENL_NAME "ethtool"
 #define ETHTOOL_GENL_VERSION 1
diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 7a849ff22dad..4e584903e3ef 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -7,4 +7,4 @@ obj-$(CONFIG_ETHTOOL_NETLINK)	+= ethtool_nl.o
 ethtool_nl-y	:= netlink.o bitset.o strset.o linkinfo.o linkmodes.o \
 		   linkstate.o debug.o wol.o features.o privflags.o rings.o \
 		   channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o \
-		   tunnels.o
+		   tunnels.o preempt.o
diff --git a/net/ethtool/common.c b/net/ethtool/common.c
index 24036e3055a1..6b47ee0565f5 100644
--- a/net/ethtool/common.c
+++ b/net/ethtool/common.c
@@ -410,3 +410,13 @@ void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops)
 	rtnl_unlock();
 }
 EXPORT_SYMBOL_GPL(ethtool_set_ethtool_phy_ops);
+
+u8 ethtool_frag_size_to_mult(u32 frag_size)
+{
+	u8 mult = (frag_size / 64) - 1;
+
+	mult = clamp_t(u8, mult, 0, 3);
+
+	return mult;
+}
+EXPORT_SYMBOL_GPL(ethtool_frag_size_to_mult);
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 50d3c8896f91..bc7d66e3ba38 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -245,6 +245,7 @@ ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
 	[ETHTOOL_MSG_PAUSE_GET]		= &ethnl_pause_request_ops,
 	[ETHTOOL_MSG_EEE_GET]		= &ethnl_eee_request_ops,
 	[ETHTOOL_MSG_TSINFO_GET]	= &ethnl_tsinfo_request_ops,
+	[ETHTOOL_MSG_PREEMPT_GET]	= &ethnl_preempt_request_ops,
 };
 
 static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback *cb)
@@ -551,6 +552,7 @@ ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 	[ETHTOOL_MSG_COALESCE_NTF]	= &ethnl_coalesce_request_ops,
 	[ETHTOOL_MSG_PAUSE_NTF]		= &ethnl_pause_request_ops,
 	[ETHTOOL_MSG_EEE_NTF]		= &ethnl_eee_request_ops,
+	[ETHTOOL_MSG_PREEMPT_NTF]	= &ethnl_preempt_request_ops,
 };
 
 /* default notification handler */
@@ -643,6 +645,7 @@ static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_COALESCE_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_PAUSE_NTF]		= ethnl_default_notify,
 	[ETHTOOL_MSG_EEE_NTF]		= ethnl_default_notify,
+	[ETHTOOL_MSG_PREEMPT_NTF]	= ethnl_default_notify,
 };
 
 void ethtool_notify(struct net_device *dev, unsigned int cmd, const void *data)
@@ -912,6 +915,22 @@ static const struct genl_ops ethtool_genl_ops[] = {
 		.policy = ethnl_tunnel_info_get_policy,
 		.maxattr = ARRAY_SIZE(ethnl_tunnel_info_get_policy) - 1,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_PREEMPT_GET,
+		.doit	= ethnl_default_doit,
+		.start	= ethnl_default_start,
+		.dumpit	= ethnl_default_dumpit,
+		.done	= ethnl_default_done,
+		.policy = ethnl_preempt_get_policy,
+		.maxattr = ARRAY_SIZE(ethnl_preempt_get_policy) - 1,
+	},
+	{
+		.cmd	= ETHTOOL_MSG_PREEMPT_SET,
+		.flags	= GENL_UNS_ADMIN_PERM,
+		.doit	= ethnl_set_preempt,
+		.policy = ethnl_preempt_set_policy,
+		.maxattr = ARRAY_SIZE(ethnl_preempt_set_policy) - 1,
+	},
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {
diff --git a/net/ethtool/netlink.h b/net/ethtool/netlink.h
index d8efec516d86..53d2e722fad3 100644
--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h
@@ -344,6 +344,7 @@ extern const struct ethnl_request_ops ethnl_coalesce_request_ops;
 extern const struct ethnl_request_ops ethnl_pause_request_ops;
 extern const struct ethnl_request_ops ethnl_eee_request_ops;
 extern const struct ethnl_request_ops ethnl_tsinfo_request_ops;
+extern const struct ethnl_request_ops ethnl_preempt_request_ops;
 
 extern const struct nla_policy ethnl_header_policy[ETHTOOL_A_HEADER_FLAGS + 1];
 extern const struct nla_policy ethnl_header_policy_stats[ETHTOOL_A_HEADER_FLAGS + 1];
@@ -375,6 +376,8 @@ extern const struct nla_policy ethnl_tsinfo_get_policy[ETHTOOL_A_TSINFO_HEADER +
 extern const struct nla_policy ethnl_cable_test_act_policy[ETHTOOL_A_CABLE_TEST_HEADER + 1];
 extern const struct nla_policy ethnl_cable_test_tdr_act_policy[ETHTOOL_A_CABLE_TEST_TDR_CFG + 1];
 extern const struct nla_policy ethnl_tunnel_info_get_policy[ETHTOOL_A_TUNNEL_INFO_HEADER + 1];
+extern const struct nla_policy ethnl_preempt_get_policy[ETHTOOL_A_PREEMPT_HEADER + 1];
+extern const struct nla_policy ethnl_preempt_set_policy[ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE + 1];
 
 int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);
 int ethnl_set_linkmodes(struct sk_buff *skb, struct genl_info *info);
@@ -392,5 +395,6 @@ int ethnl_act_cable_test_tdr(struct sk_buff *skb, struct genl_info *info);
 int ethnl_tunnel_info_doit(struct sk_buff *skb, struct genl_info *info);
 int ethnl_tunnel_info_start(struct netlink_callback *cb);
 int ethnl_tunnel_info_dumpit(struct sk_buff *skb, struct netlink_callback *cb);
+int ethnl_set_preempt(struct sk_buff *skb, struct genl_info *info);
 
 #endif /* _NET_ETHTOOL_NETLINK_H */
diff --git a/net/ethtool/preempt.c b/net/ethtool/preempt.c
new file mode 100644
index 000000000000..4f96d3c2b1d5
--- /dev/null
+++ b/net/ethtool/preempt.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "netlink.h"
+#include "common.h"
+
+struct preempt_req_info {
+	struct ethnl_req_info		base;
+};
+
+struct preempt_reply_data {
+	struct ethnl_reply_data		base;
+	struct ethtool_fp		fp;
+};
+
+#define PREEMPT_REPDATA(__reply_base) \
+	container_of(__reply_base, struct preempt_reply_data, base)
+
+const struct nla_policy
+ethnl_preempt_get_policy[] = {
+	[ETHTOOL_A_PREEMPT_HEADER]		= NLA_POLICY_NESTED(ethnl_header_policy),
+};
+
+static int preempt_prepare_data(const struct ethnl_req_info *req_base,
+				struct ethnl_reply_data *reply_base,
+				struct genl_info *info)
+{
+	struct preempt_reply_data *data = PREEMPT_REPDATA(reply_base);
+	struct net_device *dev = reply_base->dev;
+	int ret;
+
+	if (!dev->ethtool_ops->get_preempt)
+		return -EOPNOTSUPP;
+
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = dev->ethtool_ops->get_preempt(dev, &data->fp);
+	ethnl_ops_complete(dev);
+
+	return ret;
+}
+
+static int preempt_reply_size(const struct ethnl_req_info *req_base,
+			      const struct ethnl_reply_data *reply_base)
+{
+	int len = 0;
+
+	len += nla_total_size(sizeof(u8)); /* _PREEMPT_ENABLED */
+	len += nla_total_size(sizeof(u32)); /* _PREEMPT_ADD_FRAG_SIZE */
+
+	return len;
+}
+
+static int preempt_fill_reply(struct sk_buff *skb,
+			      const struct ethnl_req_info *req_base,
+			      const struct ethnl_reply_data *reply_base)
+{
+	const struct preempt_reply_data *data = PREEMPT_REPDATA(reply_base);
+	const struct ethtool_fp *preempt = &data->fp;
+
+	if (nla_put_u8(skb, ETHTOOL_A_PREEMPT_ENABLED, preempt->enabled))
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE,
+			preempt->add_frag_size))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+const struct ethnl_request_ops ethnl_preempt_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_PREEMPT_GET,
+	.reply_cmd		= ETHTOOL_MSG_PREEMPT_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_PREEMPT_HEADER,
+	.req_info_size		= sizeof(struct preempt_req_info),
+	.reply_data_size	= sizeof(struct preempt_reply_data),
+
+	.prepare_data		= preempt_prepare_data,
+	.reply_size		= preempt_reply_size,
+	.fill_reply		= preempt_fill_reply,
+};
+
+const struct nla_policy
+ethnl_preempt_set_policy[ETHTOOL_A_PREEMPT_MAX + 1] = {
+	[ETHTOOL_A_PREEMPT_HEADER]			= NLA_POLICY_NESTED(ethnl_header_policy),
+	[ETHTOOL_A_PREEMPT_ENABLED]			= NLA_POLICY_RANGE(NLA_U8, 0, 1),
+	[ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE]		= { .type = NLA_U32 },
+};
+
+int ethnl_set_preempt(struct sk_buff *skb, struct genl_info *info)
+{
+	struct ethnl_req_info req_info = {};
+	struct nlattr **tb = info->attrs;
+	struct ethtool_fp preempt = {};
+	struct net_device *dev;
+	bool mod = false;
+	int ret;
+
+	ret = ethnl_parse_header_dev_get(&req_info,
+					 tb[ETHTOOL_A_PREEMPT_HEADER],
+					 genl_info_net(info), info->extack,
+					 true);
+	if (ret < 0)
+		return ret;
+	dev = req_info.dev;
+	ret = -EOPNOTSUPP;
+	if (!dev->ethtool_ops->get_preempt ||
+	    !dev->ethtool_ops->set_preempt)
+		goto out_dev;
+
+	rtnl_lock();
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out_rtnl;
+
+	ret = dev->ethtool_ops->get_preempt(dev, &preempt);
+	if (ret < 0) {
+		GENL_SET_ERR_MSG(info, "failed to retrieve frame preemption settings");
+		goto out_ops;
+	}
+
+	ethnl_update_u8(&preempt.enabled,
+			tb[ETHTOOL_A_PREEMPT_ENABLED], &mod);
+	ethnl_update_u32(&preempt.add_frag_size,
+			 tb[ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE], &mod);
+	ret = 0;
+	if (!mod)
+		goto out_ops;
+
+	ret = dev->ethtool_ops->set_preempt(dev, &preempt, info->extack);
+	if (ret < 0) {
+		GENL_SET_ERR_MSG(info, "frame preemption settings update failed");
+		goto out_ops;
+	}
+
+	ethtool_notify(dev, ETHTOOL_MSG_PREEMPT_NTF, NULL);
+
+out_ops:
+	ethnl_ops_complete(dev);
+out_rtnl:
+	rtnl_unlock();
+out_dev:
+	dev_put(dev);
+	return ret;
+}
-- 
2.30.0

Re: [PATCH net-next v2 1/8] ethtool: Add support for configuring frame preemption

[Vladimir Oltean]

On Mon, Jan 18, 2021 at 04:40:21PM -0800, Vinicius Costa Gomes wrote:
> +int ethnl_set_preempt(struct sk_buff *skb, struct genl_info *info)
> +{
> +	struct ethnl_req_info req_info = {};
> +	struct nlattr **tb = info->attrs;
> +	struct ethtool_fp preempt = {};
> +	struct net_device *dev;
> +	bool mod = false;
> +	int ret;
> +
> +	ret = ethnl_parse_header_dev_get(&req_info,
> +					 tb[ETHTOOL_A_PREEMPT_HEADER],
> +					 genl_info_net(info), info->extack,
> +					 true);
> +	if (ret < 0)
> +		return ret;
> +	dev = req_info.dev;
> +	ret = -EOPNOTSUPP;
> +	if (!dev->ethtool_ops->get_preempt ||
> +	    !dev->ethtool_ops->set_preempt)
> +		goto out_dev;
> +
> +	rtnl_lock();

I'm a bit of a noob when it comes to ethtool (netlink or otherwise).
Why do you take the rtnl_mutex when updating some purely hardware
values, what netdev state is there to protect? Can this get->modify->set
sequence be serialized using other locking mechanism than rtnl_mutex?

> +	ret = ethnl_ops_begin(dev);
> +	if (ret < 0)
> +		goto out_rtnl;
> +
> +	ret = dev->ethtool_ops->get_preempt(dev, &preempt);
> +	if (ret < 0) {
> +		GENL_SET_ERR_MSG(info, "failed to retrieve frame preemption settings");
> +		goto out_ops;
> +	}
> +
> +	ethnl_update_u8(&preempt.enabled,
> +			tb[ETHTOOL_A_PREEMPT_ENABLED], &mod);
> +	ethnl_update_u32(&preempt.add_frag_size,
> +			 tb[ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE], &mod);
> +	ret = 0;
> +	if (!mod)
> +		goto out_ops;
> +
> +	ret = dev->ethtool_ops->set_preempt(dev, &preempt, info->extack);
> +	if (ret < 0) {
> +		GENL_SET_ERR_MSG(info, "frame preemption settings update failed");
> +		goto out_ops;
> +	}
> +
> +	ethtool_notify(dev, ETHTOOL_MSG_PREEMPT_NTF, NULL);
> +
> +out_ops:
> +	ethnl_ops_complete(dev);
> +out_rtnl:
> +	rtnl_unlock();
> +out_dev:
> +	dev_put(dev);
> +	return ret;
> +}

Re: [PATCH net-next v2 1/8] ethtool: Add support for configuring frame preemption

[Vinicius Costa Gomes]

Hi Vladimir,

Vladimir Oltean <vladimir.oltean@nxp.com> writes:

> On Mon, Jan 18, 2021 at 04:40:21PM -0800, Vinicius Costa Gomes wrote:
>> +int ethnl_set_preempt(struct sk_buff *skb, struct genl_info *info)
>> +{
>> +	struct ethnl_req_info req_info = {};
>> +	struct nlattr **tb = info->attrs;
>> +	struct ethtool_fp preempt = {};
>> +	struct net_device *dev;
>> +	bool mod = false;
>> +	int ret;
>> +
>> +	ret = ethnl_parse_header_dev_get(&req_info,
>> +					 tb[ETHTOOL_A_PREEMPT_HEADER],
>> +					 genl_info_net(info), info->extack,
>> +					 true);
>> +	if (ret < 0)
>> +		return ret;
>> +	dev = req_info.dev;
>> +	ret = -EOPNOTSUPP;
>> +	if (!dev->ethtool_ops->get_preempt ||
>> +	    !dev->ethtool_ops->set_preempt)
>> +		goto out_dev;
>> +
>> +	rtnl_lock();
>
> I'm a bit of a noob when it comes to ethtool (netlink or otherwise).
> Why do you take the rtnl_mutex when updating some purely hardware
> values, what netdev state is there to protect? Can this get->modify->set
> sequence be serialized using other locking mechanism than rtnl_mutex?

From what I understand, configuration changes to netdevice should be
protected by rtnl_mutex, for example, to avoid the device disappearing
while the configuration is in progress. I don't think there's any other
finer grained lock that can be used here.


Cheers,
-- 
Vinicius

Re: [PATCH net-next v2 1/8] ethtool: Add support for configuring frame preemption

[Jakub Kicinski]

On Mon, 18 Jan 2021 16:40:21 -0800 Vinicius Costa Gomes wrote:
> +  ====================================  ======  ==========================
> +  ``ETHTOOL_A_CHANNELS_HEADER``         nested  request header

ETHTOOL_A_PREEMPT_HEADER

> +  ====================================  ======  ==========================
> +
> +Kernel response contents:
> +
> +  =====================================  ======  ==========================
> +  ``ETHTOOL_A_CHANNELS_HEADER``          nested  reply header

here as well

> +  ``ETHTOOL_A_PREEMPT_ENABLED``          u8      frame preemption enabled
> +  ``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE``    u32     Min additional frag size
> +  =====================================  ======  ==========================
> +
> +``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE`` configures the minimum non-final
> +fragment size that the receiver device supports.
> +
> +PREEMPT_SET
> +============
> +
> +Sets frame preemption parameters.
> +
> +Request contents:
> +
> +  =====================================  ======  ==========================
> +  ``ETHTOOL_A_CHANNELS_HEADER``          nested  reply header

and here

> +  ``ETHTOOL_A_PREEMPT_ENABLED``          u8      frame preemption enabled
> +  ``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE``    u32     Min additional frag size
> +  =====================================  ======  ==========================

> +struct netlink_ext_ack;

Let's move it all the way to the top, right after header includes, so
we don't have to move it again.

> +/**
> + * Convert from a Frame Preemption Additional Fragment size in bytes
> + * to a multiplier. The multiplier is defined as:
> + *	"A 2-bit integer value used to indicate the minimum size of
> + *	non-final fragments supported by the receiver on the given port
> + *	associated with the local System. This value is expressed in units
> + *	of 64 octets of additional fragment length."
> + *	Equivalent to `30.14.1.7 aMACMergeAddFragSize` from the IEEE 802.3-2018
> + *	standard.

Please double check the correct format for kdoc:

https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html

This comment should also be next to the definition of the function, 
not in the header.

> + * @frag_size: minimum non-final fragment size in bytes
> + *
> + * Returns the multiplier.
> + */
> +u8 ethtool_frag_size_to_mult(u32 frag_size);

Re: [PATCH net-next v2 1/8] ethtool: Add support for configuring frame preemption

[Vinicius Costa Gomes]

Jakub Kicinski <kuba@kernel.org> writes:

> On Mon, 18 Jan 2021 16:40:21 -0800 Vinicius Costa Gomes wrote:
>> +  ====================================  ======  ==========================
>> +  ``ETHTOOL_A_CHANNELS_HEADER``         nested  request header
>
> ETHTOOL_A_PREEMPT_HEADER
>
>> +  ====================================  ======  ==========================
>> +
>> +Kernel response contents:
>> +
>> +  =====================================  ======  ==========================
>> +  ``ETHTOOL_A_CHANNELS_HEADER``          nested  reply header
>
> here as well
>
>> +  ``ETHTOOL_A_PREEMPT_ENABLED``          u8      frame preemption enabled
>> +  ``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE``    u32     Min additional frag size
>> +  =====================================  ======  ==========================
>> +
>> +``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE`` configures the minimum non-final
>> +fragment size that the receiver device supports.
>> +
>> +PREEMPT_SET
>> +============
>> +
>> +Sets frame preemption parameters.
>> +
>> +Request contents:
>> +
>> +  =====================================  ======  ==========================
>> +  ``ETHTOOL_A_CHANNELS_HEADER``          nested  reply header
>
> and here

Ugh. Will fix these copy&pasta mistakes.

>
>> +  ``ETHTOOL_A_PREEMPT_ENABLED``          u8      frame preemption enabled
>> +  ``ETHTOOL_A_PREEMPT_ADD_FRAG_SIZE``    u32     Min additional frag size
>> +  =====================================  ======  ==========================
>
>> +struct netlink_ext_ack;
>
> Let's move it all the way to the top, right after header includes, so
> we don't have to move it again.

Sure. Will fix.
 
>
>> +/**
>> + * Convert from a Frame Preemption Additional Fragment size in bytes
>> + * to a multiplier. The multiplier is defined as:
>> + *	"A 2-bit integer value used to indicate the minimum size of
>> + *	non-final fragments supported by the receiver on the given port
>> + *	associated with the local System. This value is expressed in units
>> + *	of 64 octets of additional fragment length."
>> + *	Equivalent to `30.14.1.7 aMACMergeAddFragSize` from the IEEE 802.3-2018
>> + *	standard.
>
> Please double check the correct format for kdoc:
>
> https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html
>
> This comment should also be next to the definition of the function, 
> not in the header.

Will fix.


Cheers,
-- 
Vinicius

[PATCH net-next v2 2/8] taprio: Add support for frame preemption offload

[Vinicius Costa Gomes]

Adds a way to configure which traffic classes are marked as
preemptible and which are marked as express.

Even if frame preemption is not a "real" offload, because it can't be
executed purely in software, having this information near where the
mapping of traffic classes to queues is specified, makes it,
hopefully, easier to use.

taprio will receive the information of which traffic classes are
marked as express/preemptible, and when offloading frame preemption to
the driver will convert the information, so the driver receives which
queues are marked as express/preemptible.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 include/linux/netdevice.h      |  1 +
 include/net/pkt_sched.h        |  4 ++++
 include/uapi/linux/pkt_sched.h |  1 +
 net/sched/sch_taprio.c         | 41 ++++++++++++++++++++++++++++++----
 4 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5b949076ed23..7388c20c07a8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -858,6 +858,7 @@ enum tc_setup_type {
 	TC_SETUP_QDISC_ETS,
 	TC_SETUP_QDISC_TBF,
 	TC_SETUP_QDISC_FIFO,
+	TC_SETUP_PREEMPT,
 };
 
 /* These structures hold the attributes of bpf state that are being passed
diff --git a/include/net/pkt_sched.h b/include/net/pkt_sched.h
index 15b1b30f454e..be5ff1535332 100644
--- a/include/net/pkt_sched.h
+++ b/include/net/pkt_sched.h
@@ -183,6 +183,10 @@ struct tc_taprio_qopt_offload {
 	struct tc_taprio_sched_entry entries[];
 };
 
+struct tc_preempt_qopt_offload {
+	u32 preemptible_queues;
+};
+
 /* Reference counting */
 struct tc_taprio_qopt_offload *taprio_offload_get(struct tc_taprio_qopt_offload
 						  *offload);
diff --git a/include/uapi/linux/pkt_sched.h b/include/uapi/linux/pkt_sched.h
index 9e7c2c607845..9ca9d2e55557 100644
--- a/include/uapi/linux/pkt_sched.h
+++ b/include/uapi/linux/pkt_sched.h
@@ -1240,6 +1240,7 @@ enum {
 	TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME_EXTENSION, /* s64 */
 	TCA_TAPRIO_ATTR_FLAGS, /* u32 */
 	TCA_TAPRIO_ATTR_TXTIME_DELAY, /* u32 */
+	TCA_TAPRIO_ATTR_PREEMPT_TCS, /* u32 */
 	__TCA_TAPRIO_ATTR_MAX,
 };
 
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 6f775275826a..e4b511a0ee38 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -64,6 +64,7 @@ struct taprio_sched {
 	struct Qdisc **qdiscs;
 	struct Qdisc *root;
 	u32 flags;
+	u32 preemptible_tcs;
 	enum tk_offsets tk_offset;
 	int clockid;
 	atomic64_t picos_per_byte; /* Using picoseconds because for 10Gbps+
@@ -776,6 +777,7 @@ static const struct nla_policy taprio_policy[TCA_TAPRIO_ATTR_MAX + 1] = {
 	[TCA_TAPRIO_ATTR_SCHED_CYCLE_TIME_EXTENSION] = { .type = NLA_S64 },
 	[TCA_TAPRIO_ATTR_FLAGS]                      = { .type = NLA_U32 },
 	[TCA_TAPRIO_ATTR_TXTIME_DELAY]		     = { .type = NLA_U32 },
+	[TCA_TAPRIO_ATTR_PREEMPT_TCS]                = { .type = NLA_U32 },
 };
 
 static int fill_sched_entry(struct taprio_sched *q, struct nlattr **tb,
@@ -1268,6 +1270,7 @@ static int taprio_disable_offload(struct net_device *dev,
 				  struct netlink_ext_ack *extack)
 {
 	const struct net_device_ops *ops = dev->netdev_ops;
+	struct tc_preempt_qopt_offload preempt = { };
 	struct tc_taprio_qopt_offload *offload;
 	int err;
 
@@ -1286,13 +1289,15 @@ static int taprio_disable_offload(struct net_device *dev,
 	offload->enable = 0;
 
 	err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TAPRIO, offload);
-	if (err < 0) {
+	if (err < 0)
+		NL_SET_ERR_MSG(extack,
+			       "Device failed to disable offload");
+
+	err = ops->ndo_setup_tc(dev, TC_SETUP_PREEMPT, &preempt);
+	if (err < 0)
 		NL_SET_ERR_MSG(extack,
 			       "Device failed to disable offload");
-		goto out;
-	}
 
-out:
 	taprio_offload_free(offload);
 
 	return err;
@@ -1509,6 +1514,29 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt,
 					       mqprio->prio_tc_map[i]);
 	}
 
+	/* It's valid to enable frame preemption without any kind of
+	 * offloading being enabled, so keep it separated.
+	 */
+	if (tb[TCA_TAPRIO_ATTR_PREEMPT_TCS]) {
+		u32 preempt = nla_get_u32(tb[TCA_TAPRIO_ATTR_PREEMPT_TCS]);
+		struct tc_preempt_qopt_offload qopt = { };
+
+		if (preempt == U32_MAX) {
+			NL_SET_ERR_MSG(extack, "At least one queue must be not be preemptible");
+			err = -EINVAL;
+			goto free_sched;
+		}
+
+		qopt.preemptible_queues = tc_map_to_queue_mask(dev, preempt);
+
+		err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_PREEMPT,
+						    &qopt);
+		if (err)
+			goto free_sched;
+
+		q->preemptible_tcs = preempt;
+	}
+
 	if (FULL_OFFLOAD_IS_ENABLED(q->flags))
 		err = taprio_enable_offload(dev, q, new_admin, extack);
 	else
@@ -1665,6 +1693,7 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt,
 	 */
 	q->clockid = -1;
 	q->flags = TAPRIO_FLAGS_INVALID;
+	q->preemptible_tcs = U32_MAX;
 
 	spin_lock(&taprio_list_lock);
 	list_add(&q->taprio_list, &taprio_list);
@@ -1848,6 +1877,10 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb)
 	if (q->flags && nla_put_u32(skb, TCA_TAPRIO_ATTR_FLAGS, q->flags))
 		goto options_error;
 
+	if (q->preemptible_tcs != U32_MAX &&
+	    nla_put_u32(skb, TCA_TAPRIO_ATTR_PREEMPT_TCS, q->preemptible_tcs))
+		goto options_error;
+
 	if (q->txtime_delay &&
 	    nla_put_u32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, q->txtime_delay))
 		goto options_error;
-- 
2.30.0

Re: [PATCH net-next v2 2/8] taprio: Add support for frame preemption offload

[Jakub Kicinski]

On Mon, 18 Jan 2021 16:40:22 -0800 Vinicius Costa Gomes wrote:
> Adds a way to configure which traffic classes are marked as
> preemptible and which are marked as express.
> 
> Even if frame preemption is not a "real" offload, because it can't be
> executed purely in software, having this information near where the
> mapping of traffic classes to queues is specified, makes it,
> hopefully, easier to use.
> 
> taprio will receive the information of which traffic classes are
> marked as express/preemptible, and when offloading frame preemption to
> the driver will convert the information, so the driver receives which
> queues are marked as express/preemptible.
> 
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>

> @@ -1286,13 +1289,15 @@ static int taprio_disable_offload(struct net_device *dev,
>  	offload->enable = 0;
>  
>  	err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TAPRIO, offload);
> -	if (err < 0) {
> +	if (err < 0)
> +		NL_SET_ERR_MSG(extack,
> +			       "Device failed to disable offload");
> +
> +	err = ops->ndo_setup_tc(dev, TC_SETUP_PREEMPT, &preempt);
> +	if (err < 0)
>  		NL_SET_ERR_MSG(extack,
>  			       "Device failed to disable offload");

This was meant to say something else?

> -		goto out;
> -	}
>  
> -out:
>  	taprio_offload_free(offload);
>  
>  	return err;

Re: [PATCH net-next v2 2/8] taprio: Add support for frame preemption offload

[Vinicius Costa Gomes]

Jakub Kicinski <kuba@kernel.org> writes:

> On Mon, 18 Jan 2021 16:40:22 -0800 Vinicius Costa Gomes wrote:
>> Adds a way to configure which traffic classes are marked as
>> preemptible and which are marked as express.
>> 
>> Even if frame preemption is not a "real" offload, because it can't be
>> executed purely in software, having this information near where the
>> mapping of traffic classes to queues is specified, makes it,
>> hopefully, easier to use.
>> 
>> taprio will receive the information of which traffic classes are
>> marked as express/preemptible, and when offloading frame preemption to
>> the driver will convert the information, so the driver receives which
>> queues are marked as express/preemptible.
>> 
>> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
>
>> @@ -1286,13 +1289,15 @@ static int taprio_disable_offload(struct net_device *dev,
>>  	offload->enable = 0;
>>  
>>  	err = ops->ndo_setup_tc(dev, TC_SETUP_QDISC_TAPRIO, offload);
>> -	if (err < 0) {
>> +	if (err < 0)
>> +		NL_SET_ERR_MSG(extack,
>> +			       "Device failed to disable offload");
>> +
>> +	err = ops->ndo_setup_tc(dev, TC_SETUP_PREEMPT, &preempt);
>> +	if (err < 0)
>>  		NL_SET_ERR_MSG(extack,
>>  			       "Device failed to disable offload");
>
> This was meant to say something else?

Yeah, better to say which offload failed to be disabled. Will fix.


Cheers,
-- 
Vinicius

[PATCH net-next v2 3/8] igc: Set the RX packet buffer size for TSN mode

[Vinicius Costa Gomes]

In preparation for supporting frame preemption, when entering TSN mode
set the receive packet buffer to 16KB for the Express MAC, 16KB for
the Preemptible MAC and 2KB for the BMC, according to the datasheet
section 7.1.3.2.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_defines.h |  2 ++
 drivers/net/ethernet/intel/igc/igc_tsn.c     | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
index 32f5fd684139..0e78abfd99ee 100644
--- a/drivers/net/ethernet/intel/igc/igc_defines.h
+++ b/drivers/net/ethernet/intel/igc/igc_defines.h
@@ -351,6 +351,8 @@
 #define IGC_RXPBS_CFG_TS_EN	0x80000000 /* Timestamp in Rx buffer */
 
 #define IGC_TXPBSIZE_TSN	0x04145145 /* 5k bytes buffer for each queue */
+#define IGC_RXPBSIZE_TSN	0x00010090 /* 16KB for EXP + 16KB for BE + 2KB for BMC */
+#define IGC_RXPBSIZE_SIZE_MASK	0x0001FFFF
 
 #define IGC_DTXMXPKTSZ_TSN	0x19 /* 1600 bytes of max TX DMA packet size */
 #define IGC_DTXMXPKTSZ_DEFAULT	0x98 /* 9728-byte Jumbo frames */
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 174103c4bea6..38451cf05ac6 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -24,7 +24,7 @@ static bool is_any_launchtime(struct igc_adapter *adapter)
 static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
-	u32 tqavctrl;
+	u32 tqavctrl, rxpbs;
 	int i;
 
 	if (!(adapter->flags & IGC_FLAG_TSN_QBV_ENABLED))
@@ -35,6 +35,11 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 	wr32(IGC_TXPBS, I225_TXPBSIZE_DEFAULT);
 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_DEFAULT);
 
+	rxpbs = rd32(IGC_RXPBS) & ~IGC_RXPBSIZE_SIZE_MASK;
+	rxpbs |= I225_RXPBSIZE_DEFAULT;
+
+	wr32(IGC_RXPBS, rxpbs);
+
 	tqavctrl = rd32(IGC_TQAVCTRL);
 	tqavctrl &= ~(IGC_TQAVCTRL_TRANSMIT_MODE_TSN |
 		      IGC_TQAVCTRL_ENHANCED_QAV);
@@ -64,7 +69,7 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
 	u32 tqavctrl, baset_l, baset_h;
-	u32 sec, nsec, cycle;
+	u32 sec, nsec, cycle, rxpbs;
 	ktime_t base_time, systim;
 	int i;
 
@@ -79,6 +84,11 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 	wr32(IGC_TXPBS, IGC_TXPBSIZE_TSN);
 
 	tqavctrl = rd32(IGC_TQAVCTRL);
+	rxpbs = rd32(IGC_RXPBS) & ~IGC_RXPBSIZE_SIZE_MASK;
+	rxpbs |= IGC_RXPBSIZE_TSN;
+
+	wr32(IGC_RXPBS, rxpbs);
+
 	tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN | IGC_TQAVCTRL_ENHANCED_QAV;
 	wr32(IGC_TQAVCTRL, tqavctrl);
 
-- 
2.30.0

[PATCH net-next v2 4/8] igc: Only dump registers if configured to dump HW information

[Vinicius Costa Gomes]

To avoid polluting the users logs with register dumps, only dump the
adapter's registers if configured to do so.

If users want to enable HW status messages they can do:

$ ethtool -s IFACE msglvl hw on

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_dump.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/intel/igc/igc_dump.c b/drivers/net/ethernet/intel/igc/igc_dump.c
index 4b9ec7d0b727..90b754b429ff 100644
--- a/drivers/net/ethernet/intel/igc/igc_dump.c
+++ b/drivers/net/ethernet/intel/igc/igc_dump.c
@@ -308,6 +308,9 @@ void igc_regs_dump(struct igc_adapter *adapter)
 	struct igc_hw *hw = &adapter->hw;
 	struct igc_reg_info *reginfo;
 
+	if (!netif_msg_hw(adapter))
+		return;
+
 	/* Print Registers */
 	netdev_info(adapter->netdev, "Register Dump\n");
 	netdev_info(adapter->netdev, "Register Name   Value\n");
-- 
2.30.0

[PATCH net-next v2 5/8] igc: Avoid TX Hangs because long cycles

[Vinicius Costa Gomes]

Avoid possible TX Hangs caused by using long Qbv cycles. In some
cases, using long cycles (more than 1 second) can cause transmissions
to be blocked for that time. As the TX Hang timeout is close to 1
second, we may need to reduce the cycle time to something more
reasonable: the value chosen is 1ms.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_main.c | 4 ++--
 drivers/net/ethernet/intel/igc/igc_tsn.c  | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index afd6a62da29d..f1b31fa04734 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -4693,12 +4693,12 @@ static int igc_save_launchtime_params(struct igc_adapter *adapter, int queue,
 	if (adapter->base_time)
 		return 0;
 
-	adapter->cycle_time = NSEC_PER_SEC;
+	adapter->cycle_time = NSEC_PER_MSEC;
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {
 		ring = adapter->tx_ring[i];
 		ring->start_time = 0;
-		ring->end_time = NSEC_PER_SEC;
+		ring->end_time = NSEC_PER_MSEC;
 	}
 
 	return 0;
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 38451cf05ac6..f5a5527adb21 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -54,11 +54,11 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 
 		wr32(IGC_TXQCTL(i), 0);
 		wr32(IGC_STQT(i), 0);
-		wr32(IGC_ENDQT(i), NSEC_PER_SEC);
+		wr32(IGC_ENDQT(i), NSEC_PER_MSEC);
 	}
 
-	wr32(IGC_QBVCYCLET_S, NSEC_PER_SEC);
-	wr32(IGC_QBVCYCLET, NSEC_PER_SEC);
+	wr32(IGC_QBVCYCLET_S, NSEC_PER_MSEC);
+	wr32(IGC_QBVCYCLET, NSEC_PER_MSEC);
 
 	adapter->flags &= ~IGC_FLAG_TSN_QBV_ENABLED;
 
-- 
2.30.0

[PATCH net-next v2 6/8] igc: Add support for tuning frame preemption via ethtool

[Vinicius Costa Gomes]

The tc subsystem sets which queues are marked as preemptible, it's the
role of ethtool to control more hardware specific parameters. These
parameters include:

 - enabling the frame preemption hardware: As enabling frame
 preemption may have other requirements before it can be enabled, it's
 exposed via the ethtool API;

 - mininum fragment size multiplier: expressed in usually in the form
 of (1 + N)*64, this number indicates what's the size of the minimum
 fragment that can be preempted.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 drivers/net/ethernet/intel/igc/igc.h         | 12 +++++
 drivers/net/ethernet/intel/igc/igc_defines.h |  4 ++
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 53 ++++++++++++++++++++
 drivers/net/ethernet/intel/igc/igc_tsn.c     | 25 +++++++--
 4 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index 35baae900c1f..1067c46e0bc2 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -87,6 +87,7 @@ struct igc_ring {
 	u8 queue_index;                 /* logical index of the ring*/
 	u8 reg_idx;                     /* physical index of the ring */
 	bool launchtime_enable;         /* true if LaunchTime is enabled */
+	bool preemptible;		/* true if not express */
 
 	u32 start_time;
 	u32 end_time;
@@ -165,6 +166,8 @@ struct igc_adapter {
 
 	ktime_t base_time;
 	ktime_t cycle_time;
+	bool frame_preemption_active;
+	u8 add_frag_size;
 
 	/* OS defined structs */
 	struct pci_dev *pdev;
@@ -262,6 +265,10 @@ extern char igc_driver_name[];
 #define IGC_FLAG_VLAN_PROMISC		BIT(15)
 #define IGC_FLAG_RX_LEGACY		BIT(16)
 #define IGC_FLAG_TSN_QBV_ENABLED	BIT(17)
+#define IGC_FLAG_TSN_PREEMPT_ENABLED	BIT(18)
+
+#define IGC_FLAG_TSN_ANY_ENABLED \
+	(IGC_FLAG_TSN_QBV_ENABLED | IGC_FLAG_TSN_PREEMPT_ENABLED)
 
 #define IGC_FLAG_RSS_FIELD_IPV4_UDP	BIT(6)
 #define IGC_FLAG_RSS_FIELD_IPV6_UDP	BIT(7)
@@ -310,6 +317,11 @@ extern char igc_driver_name[];
 #define IGC_I225_RX_LATENCY_1000	300
 #define IGC_I225_RX_LATENCY_2500	1485
 
+/* From the datasheet section 8.12.4 Tx Qav Control TQAVCTRL,
+ * MIN_FRAG initial value.
+ */
+#define IGC_I225_MIN_FRAG_SIZE_DEFAULT	68
+
 /* RX and TX descriptor control thresholds.
  * PTHRESH - MAC will consider prefetch if it has fewer than this number of
  *           descriptors available in its onboard memory.
diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
index 0e78abfd99ee..c2155d109bd6 100644
--- a/drivers/net/ethernet/intel/igc/igc_defines.h
+++ b/drivers/net/ethernet/intel/igc/igc_defines.h
@@ -410,10 +410,14 @@
 /* Transmit Scheduling */
 #define IGC_TQAVCTRL_TRANSMIT_MODE_TSN	0x00000001
 #define IGC_TQAVCTRL_ENHANCED_QAV	0x00000008
+#define IGC_TQAVCTRL_PREEMPT_ENA	0x00000002
+#define IGC_TQAVCTRL_MIN_FRAG_MASK	0x0000C000
+#define IGC_TQAVCTRL_MIN_FRAG_SHIFT	14
 
 #define IGC_TXQCTL_QUEUE_MODE_LAUNCHT	0x00000001
 #define IGC_TXQCTL_STRICT_CYCLE		0x00000002
 #define IGC_TXQCTL_STRICT_END		0x00000004
+#define IGC_TXQCTL_PREEMPTABLE		0x00000008
 
 /* Receive Checksum Control */
 #define IGC_RXCSUM_CRCOFL	0x00000800   /* CRC32 offload enable */
diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 61d331ce38cd..2ed32ac0dca8 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -8,6 +8,7 @@
 
 #include "igc.h"
 #include "igc_diag.h"
+#include "igc_tsn.h"
 
 /* forward declaration */
 struct igc_stats {
@@ -1636,6 +1637,56 @@ static int igc_ethtool_set_eee(struct net_device *netdev,
 	return 0;
 }
 
+static int igc_ethtool_get_preempt(struct net_device *netdev,
+				   struct ethtool_fp *fpcmd)
+{
+	struct igc_adapter *adapter = netdev_priv(netdev);
+
+	fpcmd->enabled = adapter->frame_preemption_active;
+	fpcmd->add_frag_size = adapter->add_frag_size;
+
+	return 0;
+}
+
+static int igc_ethtool_set_preempt(struct net_device *netdev,
+				   struct ethtool_fp *fpcmd,
+				   struct netlink_ext_ack *extack)
+{
+	struct igc_adapter *adapter = netdev_priv(netdev);
+	int i;
+
+	if (fpcmd->add_frag_size < 68 || fpcmd->add_frag_size > 260) {
+		NL_SET_ERR_MSG(extack, "Invalid value for add-frag-size");
+		return -EINVAL;
+	}
+
+	adapter->frame_preemption_active = fpcmd->enabled;
+	adapter->add_frag_size = fpcmd->add_frag_size;
+
+	if (!adapter->frame_preemption_active)
+		goto done;
+
+	/* Enabling frame preemption requires TSN mode to be enabled,
+	 * which requires a schedule to be active. So, if there isn't
+	 * a schedule already configured, configure a simple one, with
+	 * all queues open, with 1ms cycle time.
+	 */
+	if (adapter->base_time)
+		goto done;
+
+	adapter->cycle_time = NSEC_PER_MSEC;
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *ring = adapter->tx_ring[i];
+
+		ring->start_time = 0;
+		ring->end_time = NSEC_PER_MSEC;
+	}
+
+done:
+	return igc_tsn_offload_apply(adapter);
+}
+
 static int igc_ethtool_begin(struct net_device *netdev)
 {
 	struct igc_adapter *adapter = netdev_priv(netdev);
@@ -1915,6 +1966,8 @@ static const struct ethtool_ops igc_ethtool_ops = {
 	.get_ts_info		= igc_ethtool_get_ts_info,
 	.get_channels		= igc_ethtool_get_channels,
 	.set_channels		= igc_ethtool_set_channels,
+	.get_preempt		= igc_ethtool_get_preempt,
+	.set_preempt		= igc_ethtool_set_preempt,
 	.get_priv_flags		= igc_ethtool_get_priv_flags,
 	.set_priv_flags		= igc_ethtool_set_priv_flags,
 	.get_eee		= igc_ethtool_get_eee,
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index f5a5527adb21..31aa9eed3ae3 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -30,7 +30,10 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 	if (!(adapter->flags & IGC_FLAG_TSN_QBV_ENABLED))
 		return 0;
 
+	adapter->base_time = 0;
 	adapter->cycle_time = 0;
+	adapter->frame_preemption_active = false;
+	adapter->add_frag_size = IGC_I225_MIN_FRAG_SIZE_DEFAULT;
 
 	wr32(IGC_TXPBS, I225_TXPBSIZE_DEFAULT);
 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_DEFAULT);
@@ -42,7 +45,8 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 
 	tqavctrl = rd32(IGC_TQAVCTRL);
 	tqavctrl &= ~(IGC_TQAVCTRL_TRANSMIT_MODE_TSN |
-		      IGC_TQAVCTRL_ENHANCED_QAV);
+		      IGC_TQAVCTRL_ENHANCED_QAV | IGC_TQAVCTRL_PREEMPT_ENA |
+		      IGC_TQAVCTRL_MIN_FRAG_MASK);
 	wr32(IGC_TQAVCTRL, tqavctrl);
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {
@@ -51,6 +55,7 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 		ring->start_time = 0;
 		ring->end_time = 0;
 		ring->launchtime_enable = false;
+		ring->preemptible = false;
 
 		wr32(IGC_TXQCTL(i), 0);
 		wr32(IGC_STQT(i), 0);
@@ -71,6 +76,7 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 	u32 tqavctrl, baset_l, baset_h;
 	u32 sec, nsec, cycle, rxpbs;
 	ktime_t base_time, systim;
+	u8 frag_size_mult;
 	int i;
 
 	if (adapter->flags & IGC_FLAG_TSN_QBV_ENABLED)
@@ -83,13 +89,22 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_TSN);
 	wr32(IGC_TXPBS, IGC_TXPBSIZE_TSN);
 
-	tqavctrl = rd32(IGC_TQAVCTRL);
 	rxpbs = rd32(IGC_RXPBS) & ~IGC_RXPBSIZE_SIZE_MASK;
 	rxpbs |= IGC_RXPBSIZE_TSN;
 
 	wr32(IGC_RXPBS, rxpbs);
 
+	tqavctrl = rd32(IGC_TQAVCTRL) &
+		~(IGC_TQAVCTRL_MIN_FRAG_MASK | IGC_TQAVCTRL_PREEMPT_ENA);
 	tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN | IGC_TQAVCTRL_ENHANCED_QAV;
+
+	if (adapter->frame_preemption_active)
+		tqavctrl |= IGC_TQAVCTRL_PREEMPT_ENA;
+
+	frag_size_mult = ethtool_frag_size_to_mult(adapter->add_frag_size);
+
+	tqavctrl |= frag_size_mult << IGC_TQAVCTRL_MIN_FRAG_SHIFT;
+
 	wr32(IGC_TQAVCTRL, tqavctrl);
 
 	wr32(IGC_QBVCYCLET_S, cycle);
@@ -115,6 +130,9 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 		if (ring->launchtime_enable)
 			txqctl |= IGC_TXQCTL_QUEUE_MODE_LAUNCHT;
 
+		if (ring->preemptible)
+			txqctl |= IGC_TXQCTL_PREEMPTABLE;
+
 		wr32(IGC_TXQCTL(i), txqctl);
 	}
 
@@ -142,7 +160,8 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 
 int igc_tsn_offload_apply(struct igc_adapter *adapter)
 {
-	bool is_any_enabled = adapter->base_time || is_any_launchtime(adapter);
+	bool is_any_enabled = adapter->base_time ||
+		is_any_launchtime(adapter) || adapter->frame_preemption_active;
 
 	if (!(adapter->flags & IGC_FLAG_TSN_QBV_ENABLED) && !is_any_enabled)
 		return 0;
-- 
2.30.0

Re: [PATCH net-next v2 6/8] igc: Add support for tuning frame preemption via ethtool

[Jakub Kicinski]

On Mon, 18 Jan 2021 16:40:26 -0800 Vinicius Costa Gomes wrote:
> +		NL_SET_ERR_MSG(extack, "Invalid value for add-frag-size");

NL_SET_ERR_MSG_MOD

Re: [PATCH net-next v2 6/8] igc: Add support for tuning frame preemption via ethtool

[Vinicius Costa Gomes]

Jakub Kicinski <kuba@kernel.org> writes:

> On Mon, 18 Jan 2021 16:40:26 -0800 Vinicius Costa Gomes wrote:
>> +		NL_SET_ERR_MSG(extack, "Invalid value for add-frag-size");
>
> NL_SET_ERR_MSG_MOD

Will fix. Thanks.


Cheers,
-- 
Vinicius

[PATCH net-next v2 7/8] igc: Add support for Frame Preemption offload

[Vinicius Costa Gomes]

After the set of queues that are marked as preemptible are exposed to
the driver we can configure the hardware to enable the frame
preemption functionality.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_main.c | 32 +++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index f1b31fa04734..6a09f37ba7ed 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -4818,6 +4818,23 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 	return 0;
 }
 
+static int igc_save_frame_preemption(struct igc_adapter *adapter,
+				     struct tc_preempt_qopt_offload *qopt)
+{
+	u32 preempt;
+	int i;
+
+	preempt = qopt->preemptible_queues;
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *ring = adapter->tx_ring[i];
+
+		ring->preemptible = preempt & BIT(i);
+	}
+
+	return 0;
+}
+
 static int igc_tsn_enable_qbv_scheduling(struct igc_adapter *adapter,
 					 struct tc_taprio_qopt_offload *qopt)
 {
@@ -4834,6 +4851,18 @@ static int igc_tsn_enable_qbv_scheduling(struct igc_adapter *adapter,
 	return igc_tsn_offload_apply(adapter);
 }
 
+static int igc_tsn_enable_frame_preemption(struct igc_adapter *adapter,
+					   struct tc_preempt_qopt_offload *qopt)
+{
+	int err;
+
+	err = igc_save_frame_preemption(adapter, qopt);
+	if (err)
+		return err;
+
+	return igc_tsn_offload_apply(adapter);
+}
+
 static int igc_setup_tc(struct net_device *dev, enum tc_setup_type type,
 			void *type_data)
 {
@@ -4846,6 +4875,9 @@ static int igc_setup_tc(struct net_device *dev, enum tc_setup_type type,
 	case TC_SETUP_QDISC_ETF:
 		return igc_tsn_enable_launchtime(adapter, type_data);
 
+	case TC_SETUP_PREEMPT:
+		return igc_tsn_enable_frame_preemption(adapter, type_data);
+
 	default:
 		return -EOPNOTSUPP;
 	}
-- 
2.30.0

[PATCH net-next v2 8/8] igc: Separate TSN configurations that can be updated

[Vinicius Costa Gomes]

Some TSN features can be enabled during runtime, but most of the
features need an adapter reset to be disabled.

To better keep track of this, separate the process into an "_apply"
and a "reset" functions, "_apply" will run with the adapter in
potencially "dirty" state, and if necessary will request an adapter
reset, so "_reset" always run with a "clean" adapter.

The idea is to make the process easier to follow.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_main.c |  21 ++--
 drivers/net/ethernet/intel/igc/igc_tsn.c  | 139 +++++++++++++++-------
 drivers/net/ethernet/intel/igc/igc_tsn.h  |   1 +
 3 files changed, 102 insertions(+), 59 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 6a09f37ba7ed..8f94b53de2df 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -108,7 +108,7 @@ void igc_reset(struct igc_adapter *adapter)
 	igc_ptp_reset(adapter);
 
 	/* Re-enable TSN offloading, where applicable. */
-	igc_tsn_offload_apply(adapter);
+	igc_tsn_reset(adapter);
 
 	igc_get_phy_info(hw);
 }
@@ -4824,6 +4824,11 @@ static int igc_save_frame_preemption(struct igc_adapter *adapter,
 	u32 preempt;
 	int i;
 
+	/* What we want here is just to save the configuration, so
+	 * when frame preemption is enabled via ethtool, which queues
+	 * are marked as preemptible is saved.
+	 */
+
 	preempt = qopt->preemptible_queues;
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {
@@ -4851,18 +4856,6 @@ static int igc_tsn_enable_qbv_scheduling(struct igc_adapter *adapter,
 	return igc_tsn_offload_apply(adapter);
 }
 
-static int igc_tsn_enable_frame_preemption(struct igc_adapter *adapter,
-					   struct tc_preempt_qopt_offload *qopt)
-{
-	int err;
-
-	err = igc_save_frame_preemption(adapter, qopt);
-	if (err)
-		return err;
-
-	return igc_tsn_offload_apply(adapter);
-}
-
 static int igc_setup_tc(struct net_device *dev, enum tc_setup_type type,
 			void *type_data)
 {
@@ -4876,7 +4869,7 @@ static int igc_setup_tc(struct net_device *dev, enum tc_setup_type type,
 		return igc_tsn_enable_launchtime(adapter, type_data);
 
 	case TC_SETUP_PREEMPT:
-		return igc_tsn_enable_frame_preemption(adapter, type_data);
+		return igc_save_frame_preemption(adapter, type_data);
 
 	default:
 		return -EOPNOTSUPP;
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 31aa9eed3ae3..fdb472a80967 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -18,8 +18,24 @@ static bool is_any_launchtime(struct igc_adapter *adapter)
 	return false;
 }
 
+static unsigned int igc_tsn_new_flags(struct igc_adapter *adapter)
+{
+	unsigned int new_flags = adapter->flags & ~IGC_FLAG_TSN_ANY_ENABLED;
+
+	if (adapter->base_time)
+		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
+
+	if (is_any_launchtime(adapter))
+		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
+
+	if (adapter->frame_preemption_active)
+		new_flags |= IGC_FLAG_TSN_PREEMPT_ENABLED;
+
+	return new_flags;
+}
+
 /* Returns the TSN specific registers to their default values after
- * TSN offloading is disabled.
+ * the adapter is reset.
  */
 static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 {
@@ -27,9 +43,6 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 	u32 tqavctrl, rxpbs;
 	int i;
 
-	if (!(adapter->flags & IGC_FLAG_TSN_QBV_ENABLED))
-		return 0;
-
 	adapter->base_time = 0;
 	adapter->cycle_time = 0;
 	adapter->frame_preemption_active = false;
@@ -65,38 +78,25 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 	wr32(IGC_QBVCYCLET_S, NSEC_PER_MSEC);
 	wr32(IGC_QBVCYCLET, NSEC_PER_MSEC);
 
-	adapter->flags &= ~IGC_FLAG_TSN_QBV_ENABLED;
+	adapter->flags &= ~IGC_FLAG_TSN_ANY_ENABLED;
 
 	return 0;
 }
 
-static int igc_tsn_enable_offload(struct igc_adapter *adapter)
+static int igc_tsn_update_params(struct igc_adapter *adapter)
 {
 	struct igc_hw *hw = &adapter->hw;
-	u32 tqavctrl, baset_l, baset_h;
-	u32 sec, nsec, cycle, rxpbs;
-	ktime_t base_time, systim;
+	unsigned int flags;
 	u8 frag_size_mult;
+	u32 tqavctrl;
 	int i;
 
-	if (adapter->flags & IGC_FLAG_TSN_QBV_ENABLED)
+	flags = igc_tsn_new_flags(adapter) & IGC_FLAG_TSN_ANY_ENABLED;
+	if (!flags)
 		return 0;
 
-	cycle = adapter->cycle_time;
-	base_time = adapter->base_time;
-
-	wr32(IGC_TSAUXC, 0);
-	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_TSN);
-	wr32(IGC_TXPBS, IGC_TXPBSIZE_TSN);
-
-	rxpbs = rd32(IGC_RXPBS) & ~IGC_RXPBSIZE_SIZE_MASK;
-	rxpbs |= IGC_RXPBSIZE_TSN;
-
-	wr32(IGC_RXPBS, rxpbs);
-
 	tqavctrl = rd32(IGC_TQAVCTRL) &
 		~(IGC_TQAVCTRL_MIN_FRAG_MASK | IGC_TQAVCTRL_PREEMPT_ENA);
-	tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN | IGC_TQAVCTRL_ENHANCED_QAV;
 
 	if (adapter->frame_preemption_active)
 		tqavctrl |= IGC_TQAVCTRL_PREEMPT_ENA;
@@ -107,9 +107,6 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 
 	wr32(IGC_TQAVCTRL, tqavctrl);
 
-	wr32(IGC_QBVCYCLET_S, cycle);
-	wr32(IGC_QBVCYCLET, cycle);
-
 	for (i = 0; i < adapter->num_tx_queues; i++) {
 		struct igc_ring *ring = adapter->tx_ring[i];
 		u32 txqctl = 0;
@@ -130,12 +127,47 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 		if (ring->launchtime_enable)
 			txqctl |= IGC_TXQCTL_QUEUE_MODE_LAUNCHT;
 
-		if (ring->preemptible)
+		if (adapter->frame_preemption_active && ring->preemptible)
 			txqctl |= IGC_TXQCTL_PREEMPTABLE;
 
 		wr32(IGC_TXQCTL(i), txqctl);
 	}
 
+	adapter->flags = igc_tsn_new_flags(adapter);
+
+	return 0;
+}
+
+static int igc_tsn_enable_offload(struct igc_adapter *adapter)
+{
+	struct igc_hw *hw = &adapter->hw;
+	u32 baset_l, baset_h, tqavctrl;
+	u32 sec, nsec, cycle, rxpbs;
+	ktime_t base_time, systim;
+
+	tqavctrl = rd32(IGC_TQAVCTRL);
+	tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN | IGC_TQAVCTRL_ENHANCED_QAV;
+
+	wr32(IGC_TQAVCTRL, tqavctrl);
+
+	wr32(IGC_TSAUXC, 0);
+	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_TSN);
+	wr32(IGC_TXPBS, IGC_TXPBSIZE_TSN);
+
+	rxpbs = rd32(IGC_RXPBS) & ~IGC_RXPBSIZE_SIZE_MASK;
+	rxpbs |= IGC_RXPBSIZE_TSN;
+
+	wr32(IGC_RXPBS, rxpbs);
+
+	if (!adapter->base_time)
+		goto done;
+
+	cycle = adapter->cycle_time;
+	base_time = adapter->base_time;
+
+	wr32(IGC_QBVCYCLET_S, cycle);
+	wr32(IGC_QBVCYCLET, cycle);
+
 	nsec = rd32(IGC_SYSTIML);
 	sec = rd32(IGC_SYSTIMH);
 
@@ -153,34 +185,51 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 	wr32(IGC_BASET_H, baset_h);
 	wr32(IGC_BASET_L, baset_l);
 
-	adapter->flags |= IGC_FLAG_TSN_QBV_ENABLED;
+done:
+	igc_tsn_update_params(adapter);
 
 	return 0;
 }
 
+int igc_tsn_reset(struct igc_adapter *adapter)
+{
+	unsigned int new_flags;
+	int err = 0;
+
+	new_flags = igc_tsn_new_flags(adapter);
+
+	if (!(new_flags & IGC_FLAG_TSN_ANY_ENABLED))
+		return igc_tsn_disable_offload(adapter);
+
+	err = igc_tsn_enable_offload(adapter);
+	if (err < 0)
+		return err;
+
+	adapter->flags = new_flags;
+
+	return err;
+}
+
 int igc_tsn_offload_apply(struct igc_adapter *adapter)
 {
-	bool is_any_enabled = adapter->base_time ||
-		is_any_launchtime(adapter) || adapter->frame_preemption_active;
+	unsigned int new_flags, old_flags;
 
-	if (!(adapter->flags & IGC_FLAG_TSN_QBV_ENABLED) && !is_any_enabled)
-		return 0;
+	old_flags = adapter->flags;
+	new_flags = igc_tsn_new_flags(adapter);
 
-	if (!is_any_enabled) {
-		int err = igc_tsn_disable_offload(adapter);
+	if (old_flags == new_flags)
+		return igc_tsn_update_params(adapter);
 
-		if (err < 0)
-			return err;
+	/* Enabling features work without resetting the adapter */
+	if (new_flags > old_flags)
+		return igc_tsn_enable_offload(adapter);
 
-		/* The BASET registers aren't cleared when writing
-		 * into them, force a reset if the interface is
-		 * running.
-		 */
-		if (netif_running(adapter->netdev))
-			schedule_work(&adapter->reset_task);
+	adapter->flags = new_flags;
 
-		return 0;
-	}
+	if (!netif_running(adapter->netdev))
+		return igc_tsn_enable_offload(adapter);
 
-	return igc_tsn_enable_offload(adapter);
+	schedule_work(&adapter->reset_task);
+
+	return 0;
 }
diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.h b/drivers/net/ethernet/intel/igc/igc_tsn.h
index f76bc86ddccd..1512307f5a52 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.h
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.h
@@ -5,5 +5,6 @@
 #define _IGC_TSN_H_
 
 int igc_tsn_offload_apply(struct igc_adapter *adapter);
+int igc_tsn_reset(struct igc_adapter *adapter);
 
 #endif /* _IGC_BASE_H */
-- 
2.30.0