[PATCH net-next 1/2] netdevsim: add link speed support

[Hangbin Liu <hangbin.liu@linux.dev>]

From: Hangbin Liu <liuhangbin@kylinos.cn>

Add ethtool get/set_link_ksettings callbacks to netdevsim so the simulated
link speed and duplex can be queried and configured from userspace.

Move NSIM_LINK_SPEED_MAX and NSIM_LINK_SPEED_UNIT from dev.c to netdevsim.h
so they are available to both the devlink rate path and the new ethtool
code. The set callback rejects speeds exceeding NSIM_LINK_SPEED_MAX.

The default link speed is set to SPEED_5000 with DUPLEX_FULL, matching the
existing NSIM_LINK_SPEED_MAX definition.

Signed-off-by: Hangbin Liu <liuhangbin@kylinos.cn>
---
 drivers/net/netdevsim/dev.c       |  6 ------
 drivers/net/netdevsim/ethtool.c   | 30 ++++++++++++++++++++++++++++++
 drivers/net/netdevsim/netdevsim.h |  8 ++++++++
 3 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index feb88ccbbced..729ce80f6c83 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -1138,12 +1138,6 @@ nsim_dev_devlink_trap_policer_counter_get(struct devlink *devlink,
 	return 0;
 }
 
-#define NSIM_LINK_SPEED_MAX     5000 /* Mbps */
-#define NSIM_LINK_SPEED_UNIT    125000 /* 1 Mbps given in bytes/sec to avoid
-					* u64 overflow during conversion from
-					* bytes to bits.
-					*/
-
 static int nsim_rate_bytes_to_units(char *name, u64 *rate, struct netlink_ext_ack *extack)
 {
 	u64 val;
diff --git a/drivers/net/netdevsim/ethtool.c b/drivers/net/netdevsim/ethtool.c
index 025ea79879f3..59768bd7b620 100644
--- a/drivers/net/netdevsim/ethtool.c
+++ b/drivers/net/netdevsim/ethtool.c
@@ -205,6 +205,30 @@ static int nsim_get_ts_info(struct net_device *dev,
 	return 0;
 }
 
+static int nsim_get_link_ksettings(struct net_device *dev,
+				   struct ethtool_link_ksettings *cmd)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	cmd->base.speed		= ns->ethtool.speed;
+	cmd->base.duplex	= ns->ethtool.duplex;
+	cmd->base.port		= PORT_OTHER;
+	cmd->base.autoneg	= AUTONEG_DISABLE;
+	return 0;
+}
+
+static int nsim_set_link_ksettings(struct net_device *dev,
+				   const struct ethtool_link_ksettings *cmd)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	if (cmd->base.speed > NSIM_LINK_SPEED_MAX)
+		return -EINVAL;
+
+	return ethtool_virtdev_set_link_ksettings(dev, cmd, &ns->ethtool.speed,
+						  &ns->ethtool.duplex);
+}
+
 static const struct ethtool_ops nsim_ethtool_ops = {
 	.supported_coalesce_params	= ETHTOOL_COALESCE_ALL_PARAMS,
 	.supported_ring_params		= ETHTOOL_RING_USE_TCP_DATA_SPLIT |
@@ -223,6 +247,8 @@ static const struct ethtool_ops nsim_ethtool_ops = {
 	.set_fecparam			= nsim_set_fecparam,
 	.get_fec_stats			= nsim_get_fec_stats,
 	.get_ts_info			= nsim_get_ts_info,
+	.get_link_ksettings		= nsim_get_link_ksettings,
+	.set_link_ksettings		= nsim_set_link_ksettings,
 };
 
 static void nsim_ethtool_ring_init(struct netdevsim *ns)
@@ -250,12 +276,16 @@ void nsim_ethtool_init(struct netdevsim *ns)
 	ns->ethtool.fec.active_fec = ETHTOOL_FEC_NONE;
 
 	ns->ethtool.channels = ns->nsim_bus_dev->num_queues;
+	ns->ethtool.duplex = DUPLEX_FULL;
+	ns->ethtool.speed = SPEED_5000;
 
 	ethtool = debugfs_create_dir("ethtool", ns->nsim_dev_port->ddir);
 	ns->ethtool_ddir = ethtool;
 
 	debugfs_create_u32("get_err", 0600, ethtool, &ns->ethtool.get_err);
 	debugfs_create_u32("set_err", 0600, ethtool, &ns->ethtool.set_err);
+	debugfs_create_u32("speed", 0600, ethtool, &ns->ethtool.speed);
+	debugfs_create_u8("duplex", 0600, ethtool, &ns->ethtool.duplex);
 
 	dir = debugfs_create_dir("pause", ethtool);
 	debugfs_create_bool("report_stats_rx", 0600, dir,
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 55aec41237b9..ce0d0dea00fb 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -39,6 +39,11 @@
 
 #define NSIM_HDS_THRESHOLD_MAX		1024
 
+#define NSIM_LINK_SPEED_MAX     5000 /* Mbps */
+#define NSIM_LINK_SPEED_UNIT    125000 /* 1 Mbps given in bytes/sec to avoid
+					* u64 overflow during conversion from
+					* bytes to bits.
+					*/
 struct nsim_sa {
 	struct xfrm_state *xs;
 	__be32 ipaddr[4];
@@ -95,6 +100,9 @@ struct nsim_ethtool {
 	struct ethtool_coalesce coalesce;
 	struct ethtool_ringparam ring;
 	struct ethtool_fecparam fec;
+
+	u32 speed;
+	u8 duplex;
 };
 
 struct nsim_rq {

-- 
2.55.0