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mac80211: backport support for background radar detection
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Will be used in an upcoming mt76 update

Signed-off-by: Felix Fietkau <nbd@nbd.name>
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nbd168 committed Feb 3, 2022
1 parent 03ea040 commit 0b5a547
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378 changes: 378 additions & 0 deletions ...el/mac80211/patches/subsys/314-cfg80211-implement-APIs-for-dedicated-radar-detectio.patch
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@@ -0,0 +1,378 @@
From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Sat, 23 Oct 2021 11:10:50 +0200
Subject: [PATCH] cfg80211: implement APIs for dedicated radar detection HW

If a dedicated (off-channel) radar detection hardware (chain)
is available in the hardware/driver, allow this to be used by
calling the NL80211_CMD_RADAR_DETECT command with a new flag
attribute requesting off-channel radar detection is used.

Offchannel CAC (channel availability check) avoids the CAC
downtime when switching to a radar channel or when turning on
the AP.

Drivers advertise support for this using the new feature flag
NL80211_EXT_FEATURE_RADAR_OFFCHAN.

Tested-by: Evelyn Tsai <evelyn.tsai@mediatek.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/7468e291ef5d05d692c1738d25b8f778d8ea5c3f.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/1e60e60fef00e14401adae81c3d49f3e5f307537.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/85fa50f57fc3adb2934c8d9ca0be30394de6b7e8.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/4b6c08671ad59aae0ac46fc94c02f31b1610eb72.1634979655.git.lorenzo@kernel.org
Link: https://lore.kernel.org/r/241849ccaf2c228873c6f8495bf87b19159ba458.1634979655.git.lorenzo@kernel.org
[remove offchan_mutex, fix cfg80211_stop_offchan_radar_detection(),
remove gfp_t argument, fix documentation, fix tracing]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---

--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4057,6 +4057,15 @@ struct mgmt_frame_regs {
* @set_sar_specs: Update the SAR (TX power) settings.
*
* @color_change: Initiate a color change.
+ *
+ * @set_radar_offchan: Configure dedicated offchannel chain available for
+ * radar/CAC detection on some hw. This chain can't be used to transmit
+ * or receive frames and it is bounded to a running wdev.
+ * Offchannel radar/CAC detection allows to avoid the CAC downtime
+ * switching to a different channel during CAC detection on the selected
+ * radar channel.
+ * The caller is expected to set chandef pointer to NULL in order to
+ * disable offchannel CAC/radar detection.
*/
struct cfg80211_ops {
int (*suspend)(struct wiphy *wiphy, struct cfg80211_wowlan *wow);
@@ -4387,6 +4396,8 @@ struct cfg80211_ops {
int (*color_change)(struct wiphy *wiphy,
struct net_device *dev,
struct cfg80211_color_change_settings *params);
+ int (*set_radar_offchan)(struct wiphy *wiphy,
+ struct cfg80211_chan_def *chandef);
};

/*
@@ -7608,6 +7619,20 @@ void cfg80211_cac_event(struct net_devic
const struct cfg80211_chan_def *chandef,
enum nl80211_radar_event event, gfp_t gfp);

+/**
+ * cfg80211_offchan_cac_event - Channel Availability Check (CAC) offchan event
+ * @wiphy: the wiphy
+ * @chandef: chandef for the current channel
+ * @event: type of event
+ *
+ * This function is called when a Channel Availability Check (CAC) is finished,
+ * started or aborted by a offchannel dedicated chain.
+ *
+ * Note that this acquires the wiphy lock.
+ */
+void cfg80211_offchan_cac_event(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef,
+ enum nl80211_radar_event event);

/**
* cfg80211_gtk_rekey_notify - notify userspace about driver rekeying
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2608,6 +2608,13 @@ enum nl80211_commands {
* Mandatory parameter for the transmitting interface to enable MBSSID.
* Optional for the non-transmitting interfaces.
*
+ * @NL80211_ATTR_RADAR_OFFCHAN: Configure dedicated offchannel chain available for
+ * radar/CAC detection on some hw. This chain can't be used to transmit
+ * or receive frames and it is bounded to a running wdev.
+ * Offchannel radar/CAC detection allows to avoid the CAC downtime
+ * switching on a different channel during CAC detection on the selected
+ * radar channel.
+ *
* @NUM_NL80211_ATTR: total number of nl80211_attrs available
* @NL80211_ATTR_MAX: highest attribute number currently defined
* @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3114,6 +3121,8 @@ enum nl80211_attrs {
NL80211_ATTR_MBSSID_CONFIG,
NL80211_ATTR_MBSSID_ELEMS,

+ NL80211_ATTR_RADAR_OFFCHAN,
+
/* add attributes here, update the policy in nl80211.c */

__NL80211_ATTR_AFTER_LAST,
@@ -6013,6 +6022,9 @@ enum nl80211_feature_flags {
* @NL80211_EXT_FEATURE_BSS_COLOR: The driver supports BSS color collision
* detection and change announcemnts.
*
+ * @NL80211_EXT_FEATURE_RADAR_OFFCHAN: Device supports offchannel radar/CAC
+ * detection.
+ *
* @NUM_NL80211_EXT_FEATURES: number of extended features.
* @MAX_NL80211_EXT_FEATURES: highest extended feature index.
*/
@@ -6078,6 +6090,7 @@ enum nl80211_ext_feature_index {
NL80211_EXT_FEATURE_SECURE_RTT,
NL80211_EXT_FEATURE_PROT_RANGE_NEGO_AND_MEASURE,
NL80211_EXT_FEATURE_BSS_COLOR,
+ NL80211_EXT_FEATURE_RADAR_OFFCHAN,

/* add new features before the definition below */
NUM_NL80211_EXT_FEATURES,
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -552,6 +552,7 @@ use_default_name:
INIT_WORK(&rdev->rfkill_block, cfg80211_rfkill_block_work);
INIT_WORK(&rdev->conn_work, cfg80211_conn_work);
INIT_WORK(&rdev->event_work, cfg80211_event_work);
+ INIT_DELAYED_WORK(&rdev->offchan_cac_work, cfg80211_offchan_cac_work);

init_waitqueue_head(&rdev->dev_wait);

@@ -1214,6 +1215,8 @@ void __cfg80211_leave(struct cfg80211_re

cfg80211_pmsr_wdev_down(wdev);

+ cfg80211_stop_offchan_radar_detection(wdev);
+
switch (wdev->iftype) {
case NL80211_IFTYPE_ADHOC:
__cfg80211_leave_ibss(rdev, dev, true);
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -84,6 +84,10 @@ struct cfg80211_registered_device {

struct delayed_work dfs_update_channels_wk;

+ struct wireless_dev *offchan_radar_wdev;
+ struct cfg80211_chan_def offchan_radar_chandef;
+ struct delayed_work offchan_cac_work;
+
/* netlink port which started critical protocol (0 means not started) */
u32 crit_proto_nlportid;

@@ -491,6 +495,15 @@ cfg80211_chandef_dfs_cac_time(struct wip

void cfg80211_sched_dfs_chan_update(struct cfg80211_registered_device *rdev);

+int
+cfg80211_start_offchan_radar_detection(struct cfg80211_registered_device *rdev,
+ struct wireless_dev *wdev,
+ struct cfg80211_chan_def *chandef);
+
+void cfg80211_stop_offchan_radar_detection(struct wireless_dev *wdev);
+
+void cfg80211_offchan_cac_work(struct work_struct *work);
+
bool cfg80211_any_wiphy_oper_chan(struct wiphy *wiphy,
struct ieee80211_channel *chan);

--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -970,3 +970,116 @@ void cfg80211_cac_event(struct net_devic
nl80211_radar_notify(rdev, chandef, event, netdev, gfp);
}
EXPORT_SYMBOL(cfg80211_cac_event);
+
+void cfg80211_offchan_cac_work(struct work_struct *work)
+{
+ struct delayed_work *delayed_work = to_delayed_work(work);
+ struct cfg80211_registered_device *rdev;
+
+ rdev = container_of(delayed_work, struct cfg80211_registered_device,
+ offchan_cac_work);
+ cfg80211_offchan_cac_event(&rdev->wiphy, &rdev->offchan_radar_chandef,
+ NL80211_RADAR_CAC_FINISHED);
+}
+
+static void
+__cfg80211_offchan_cac_event(struct cfg80211_registered_device *rdev,
+ struct wireless_dev *wdev,
+ const struct cfg80211_chan_def *chandef,
+ enum nl80211_radar_event event)
+{
+ struct wiphy *wiphy = &rdev->wiphy;
+ struct net_device *netdev;
+
+ lockdep_assert_wiphy(&rdev->wiphy);
+
+ if (event != NL80211_RADAR_CAC_STARTED && !rdev->offchan_radar_wdev)
+ return;
+
+ switch (event) {
+ case NL80211_RADAR_CAC_FINISHED:
+ cfg80211_set_dfs_state(wiphy, chandef, NL80211_DFS_AVAILABLE);
+ memcpy(&rdev->cac_done_chandef, chandef, sizeof(*chandef));
+ queue_work(cfg80211_wq, &rdev->propagate_cac_done_wk);
+ cfg80211_sched_dfs_chan_update(rdev);
+ wdev = rdev->offchan_radar_wdev;
+ rdev->offchan_radar_wdev = NULL;
+ break;
+ case NL80211_RADAR_CAC_ABORTED:
+ cancel_delayed_work(&rdev->offchan_cac_work);
+ wdev = rdev->offchan_radar_wdev;
+ rdev->offchan_radar_wdev = NULL;
+ break;
+ case NL80211_RADAR_CAC_STARTED:
+ WARN_ON(!wdev);
+ rdev->offchan_radar_wdev = wdev;
+ break;
+ default:
+ return;
+ }
+
+ netdev = wdev ? wdev->netdev : NULL;
+ nl80211_radar_notify(rdev, chandef, event, netdev, GFP_KERNEL);
+}
+
+void cfg80211_offchan_cac_event(struct wiphy *wiphy,
+ const struct cfg80211_chan_def *chandef,
+ enum nl80211_radar_event event)
+{
+ struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+
+ wiphy_lock(wiphy);
+ __cfg80211_offchan_cac_event(rdev, NULL, chandef, event);
+ wiphy_unlock(wiphy);
+}
+EXPORT_SYMBOL(cfg80211_offchan_cac_event);
+
+int
+cfg80211_start_offchan_radar_detection(struct cfg80211_registered_device *rdev,
+ struct wireless_dev *wdev,
+ struct cfg80211_chan_def *chandef)
+{
+ unsigned int cac_time_ms;
+ int err;
+
+ lockdep_assert_wiphy(&rdev->wiphy);
+
+ if (!wiphy_ext_feature_isset(&rdev->wiphy,
+ NL80211_EXT_FEATURE_RADAR_OFFCHAN))
+ return -EOPNOTSUPP;
+
+ if (rdev->offchan_radar_wdev)
+ return -EBUSY;
+
+ err = rdev_set_radar_offchan(rdev, chandef);
+ if (err)
+ return err;
+
+ cac_time_ms = cfg80211_chandef_dfs_cac_time(&rdev->wiphy, chandef);
+ if (!cac_time_ms)
+ cac_time_ms = IEEE80211_DFS_MIN_CAC_TIME_MS;
+
+ rdev->offchan_radar_chandef = *chandef;
+ __cfg80211_offchan_cac_event(rdev, wdev, chandef,
+ NL80211_RADAR_CAC_STARTED);
+ queue_delayed_work(cfg80211_wq, &rdev->offchan_cac_work,
+ msecs_to_jiffies(cac_time_ms));
+
+ return 0;
+}
+
+void cfg80211_stop_offchan_radar_detection(struct wireless_dev *wdev)
+{
+ struct wiphy *wiphy = wdev->wiphy;
+ struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+
+ lockdep_assert_wiphy(wiphy);
+
+ if (wdev != rdev->offchan_radar_wdev)
+ return;
+
+ rdev_set_radar_offchan(rdev, NULL);
+
+ __cfg80211_offchan_cac_event(rdev, NULL, NULL,
+ NL80211_RADAR_CAC_ABORTED);
+}
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -793,6 +793,7 @@ static const struct nla_policy nl80211_p
[NL80211_ATTR_MBSSID_CONFIG] =
NLA_POLICY_NESTED(nl80211_mbssid_config_policy),
[NL80211_ATTR_MBSSID_ELEMS] = { .type = NLA_NESTED },
+ [NL80211_ATTR_RADAR_OFFCHAN] = { .type = NLA_FLAG },
};

/* policy for the key attributes */
@@ -9269,12 +9270,6 @@ static int nl80211_start_radar_detection
if (err)
return err;

- if (netif_carrier_ok(dev))
- return -EBUSY;
-
- if (wdev->cac_started)
- return -EBUSY;
-
err = cfg80211_chandef_dfs_required(wiphy, &chandef, wdev->iftype);
if (err < 0)
return err;
@@ -9285,6 +9280,16 @@ static int nl80211_start_radar_detection
if (!cfg80211_chandef_dfs_usable(wiphy, &chandef))
return -EINVAL;

+ if (nla_get_flag(info->attrs[NL80211_ATTR_RADAR_OFFCHAN]))
+ return cfg80211_start_offchan_radar_detection(rdev, wdev,
+ &chandef);
+
+ if (netif_carrier_ok(dev))
+ return -EBUSY;
+
+ if (wdev->cac_started)
+ return -EBUSY;
+
/* CAC start is offloaded to HW and can't be started manually */
if (wiphy_ext_feature_isset(wiphy, NL80211_EXT_FEATURE_DFS_OFFLOAD))
return -EOPNOTSUPP;
--- a/net/wireless/rdev-ops.h
+++ b/net/wireless/rdev-ops.h
@@ -1381,4 +1381,21 @@ static inline int rdev_color_change(stru
return ret;
}

+static inline int
+rdev_set_radar_offchan(struct cfg80211_registered_device *rdev,
+ struct cfg80211_chan_def *chandef)
+{
+ struct wiphy *wiphy = &rdev->wiphy;
+ int ret;
+
+ if (!rdev->ops->set_radar_offchan)
+ return -EOPNOTSUPP;
+
+ trace_rdev_set_radar_offchan(wiphy, chandef);
+ ret = rdev->ops->set_radar_offchan(wiphy, chandef);
+ trace_rdev_return_int(wiphy, ret);
+
+ return ret;
+}
+
#endif /* __CFG80211_RDEV_OPS */
--- a/net/wireless/trace.h
+++ b/net/wireless/trace.h
@@ -3643,6 +3643,25 @@ TRACE_EVENT(cfg80211_bss_color_notify,
__entry->color_bitmap)
);

+TRACE_EVENT(rdev_set_radar_offchan,
+ TP_PROTO(struct wiphy *wiphy, struct cfg80211_chan_def *chandef),
+
+ TP_ARGS(wiphy, chandef),
+
+ TP_STRUCT__entry(
+ WIPHY_ENTRY
+ CHAN_DEF_ENTRY
+ ),
+
+ TP_fast_assign(
+ WIPHY_ASSIGN;
+ CHAN_DEF_ASSIGN(chandef)
+ ),
+
+ TP_printk(WIPHY_PR_FMT ", " CHAN_DEF_PR_FMT,
+ WIPHY_PR_ARG, CHAN_DEF_PR_ARG)
+);
+
#endif /* !__RDEV_OPS_TRACE || TRACE_HEADER_MULTI_READ */

#undef TRACE_INCLUDE_PATH

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