[PATCH 02/13] wifi: nl80211: send underlying multi-hardware channel capabilities to user space

[Karthikeyan Periyasamy]

From: Vasanthakumar Thiagarajan <quic_vthiagar at quicinc.com>

As originally discussed in the RFC [1], when driver supports multiple
physical hardware under one wiphy, wiphy->num_hw != 0, send per-hardware
supported frequency list to user space. List of frequency are reported
inside an index which identifies the hardware as in wiphy->hw_chans[].
This hardware index will be used in follow up patches to identify the
interface combination capability for each of the underlying physical
hardware abstracted under one wiphy.

[1]: https://lore.kernel.org/linux-wireless/20220920100518.19705-3-quic_vthiagar@quicinc.com/

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.1.1-00188-QCAHKSWPL_SILICONZ-1

Signed-off-by: Vasanthakumar Thiagarajan <quic_vthiagar at quicinc.com>
Co-developed-by: Karthikeyan Periyasamy <quic_periyasa at quicinc.com>
Signed-off-by: Karthikeyan Periyasamy <quic_periyasa at quicinc.com>
---
 include/uapi/linux/nl80211.h | 28 +++++++++++++++++++++
 net/wireless/nl80211.c       | 47 ++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index f917bc6c9b6f..c53c9f941663 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -2856,6 +2856,11 @@ enum nl80211_commands {
  *	%NL80211_CMD_ASSOCIATE indicating the SPP A-MSDUs
  *	are used on this connection
  *
+ * @NL80211_ATTR_MULTI_HW: nested attribute to send the hardware specific
+ *	channel capabilities to user space. Drivers registering multiple
+ *	physical hardware under a wiphy can use this attribute,
+ *	see &enum nl80211_multi_hw_mac_attrs.
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -3401,6 +3406,8 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_ASSOC_SPP_AMSDU,
 
+	NL80211_ATTR_MULTI_HW,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
@@ -7999,4 +8006,25 @@ enum nl80211_ap_settings_flags {
 	NL80211_AP_SETTINGS_SA_QUERY_OFFLOAD_SUPPORT	= 1 << 1,
 };
 
+/**
+ * nl80211_multi_hw_attrs - multi-hw attributes
+ *
+ * @NL80211_MULTI_HW_ATTR_INVALID: invalid
+ * @NL80211_MULTI_HW_ATTR_IDX: (u8) multi-HW index to refer the underlying HW
+ *	for which the supported channel list is advertised. Internally refer
+ *	the index of the wiphy's @hw_chans array.
+ * @NL80211_MULTI_HW_ATTR_FREQS: array of supported center frequencies
+ * @__NL80211_MULTI_HW_ATTR_LAST: internal use
+ * @NL80211_MULTI_HW_ATTR_MAX: maximum multi-hw mac attribute
+ */
+enum nl80211_multi_hw_attrs {
+	__NL80211_MULTI_HW_ATTR_INVALID,
+
+	NL80211_MULTI_HW_ATTR_IDX,
+	NL80211_MULTI_HW_ATTR_FREQS,
+
+	/* keep last */
+	__NL80211_MULTI_HW_ATTR_LAST,
+	NL80211_MULTI_HW_ATTR_MAX = __NL80211_MULTI_HW_ATTR_LAST - 1
+};
 #endif /* __LINUX_NL80211_H */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b4edba6b0b7b..2a5e395e2e0b 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -2392,6 +2392,47 @@ static int nl80211_put_mbssid_support(struct wiphy *wiphy, struct sk_buff *msg)
 	return -ENOBUFS;
 }
 
+static int nl80211_put_multi_hw_support(struct wiphy *wiphy,
+					struct sk_buff *msg)
+{
+	struct nlattr *hw_macs, *hw_mac;
+	struct nlattr *freqs;
+	int i, c;
+
+	if (!wiphy->num_hw)
+		return 0;
+
+	hw_macs = nla_nest_start(msg, NL80211_ATTR_MULTI_HW);
+	if (!hw_macs)
+		return -ENOBUFS;
+
+	for (i = 0; i < wiphy->num_hw; i++) {
+		hw_mac = nla_nest_start(msg, i + 1);
+		if (!hw_mac)
+			return -ENOBUFS;
+
+		if (nla_put_u8(msg, NL80211_MULTI_HW_ATTR_IDX, i))
+			return -ENOBUFS;
+
+		freqs = nla_nest_start(msg,
+				       NL80211_MULTI_HW_ATTR_FREQS);
+		if (!freqs)
+			return -ENOBUFS;
+
+		for (c = 0; c < wiphy->hw_chans[i]->n_chans; c++)
+			if (nla_put_u32(msg, c + 1,
+					wiphy->hw_chans[i]->chans[c].center_freq))
+				return -ENOBUFS;
+
+		nla_nest_end(msg, freqs);
+
+		nla_nest_end(msg, hw_mac);
+	}
+
+	nla_nest_end(msg, hw_macs);
+	return 0;
+}
+
 struct nl80211_dump_wiphy_state {
 	s64 filter_wiphy;
 	long start;
@@ -3001,6 +3042,12 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 				rdev->wiphy.hw_timestamp_max_peers))
 			goto nla_put_failure;
 
+		state->split_start++;
+		break;
+	case 17:
+		if (nl80211_put_multi_hw_support(&rdev->wiphy, msg))
+			goto nla_put_failure;
+
 		/* done */
 		state->split_start = 0;
 		break;
-- 
2.34.1