[PATCH ath-next v2] wifi: ath12k: provide MAC address list for single-radio wiphys

[Vitor Soares <ivitro@gmail.com>]

From: Vitor Soares <vitor.soares@toradex.com>

ath12k supports creating vdevs with addresses provided by mac80211.
Userspace can already make concurrent interfaces work by explicitly
assigning different locally administered addresses.

However, ath12k does not advertise an address list, so when a second
interface is created without an explicit address, mac80211 has nothing
to pick from and falls back to the permanent address. If the first
interface is already running with that address, bringing up the second
one fails with -ENOTUNIQ.

As in ath11k, provide a list of usable addresses so
ieee80211_assign_perm_addr() can hand each new interface an unused one.
Keep the first entry as the radio's own MAC address. Generate the
remaining entries as locally administered variants by changing only the
upper nibble of the first octet, which naturally limits the pool to 16
unique addresses.

The wiphy->addresses semantics are hardware-specific in ath12k: some
platforms use it as an interface MAC address pool, while others use it
for firmware-provided per-radio addresses. Gate host-generated addresses
behind host_alloc_iface_mac and enable it for WCN7850.

Handle only single-radio WCN7850 wiphys. Wiphys with more than one radio
and other hardware families behave exactly as before.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c7-00108-QCAHMTSWPL_V1.0_V2.0_SILICONZ_UPSTREAM-3

Assisted-by: LLM
Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
---
v2:
- Gate generated interface MAC address list behind hw_params
  host_alloc_iface_mac, as suggested by Kang Yang.
- Enable it only for WCN7850, the only part available for testing here.
- Add Assisted-by: tag.
- Link for v1: https://lore.kernel.org/all/20260902082219.3010793-2-ivitro@gmail.com/
---
 drivers/net/wireless/ath/ath12k/hw.h       |  1 +
 drivers/net/wireless/ath/ath12k/mac.c      | 52 ++++++++++++++++++++++
 drivers/net/wireless/ath/ath12k/wifi7/hw.c |  6 +++
 3 files changed, 59 insertions(+)

diff --git a/drivers/net/wireless/ath/ath12k/hw.h b/drivers/net/wireless/ath/ath12k/hw.h
index 011bb22e21c7..03cb35071e0b 100644
--- a/drivers/net/wireless/ath/ath12k/hw.h
+++ b/drivers/net/wireless/ath/ath12k/hw.h
@@ -238,6 +238,7 @@ struct ath12k_hw_params {
 	} client;
 
 	bool host_alloc_ml_id;
+	bool host_alloc_iface_mac;
 };
 
 struct ath12k_hw_ops {
diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index d4116ba0da08..45be5b08aa40 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -14743,6 +14743,54 @@ static void ath12k_mac_cleanup_unregister(struct ath12k *ar)
 	kfree(ar->mac.sbands[NL80211_BAND_6GHZ].channels);
 }
 
+static void ath12k_mac_cleanup_mac_address_list(struct ath12k_hw *ah)
+{
+	kfree(ah->hw->wiphy->addresses);
+}
+
+static void ath12k_mac_setup_mac_address_list(struct ath12k_hw *ah,
+					      const u8 *mac_addr)
+{
+	struct mac_address *addresses;
+	struct ath12k *ar;
+	u16 n_addresses;
+	int i;
+
+	/* The pool is derived from one base address, so it can describe only a
+	 * single-radio wiphy: with more radios each radio has its own base
+	 * address, possibly from a different ath12k_base.
+	 */
+	if (ah->num_radio != 1)
+		return;
+
+	ar = ath12k_ah_to_ar(ah, 0);
+	if (!ar->ab->hw_params->host_alloc_iface_mac)
+		return;
+
+	/* Only the upper nibble of the first octet is varied, so at most 16
+	 * addresses can be derived from one base.
+	 */
+	n_addresses = min_t(u16, TARGET_NUM_VDEVS(ar->ab), 16);
+	if (n_addresses <= 1)
+		return;
+
+	addresses = kzalloc_objs(*addresses, n_addresses);
+	if (!addresses)
+		return;
+
+	ether_addr_copy(addresses[0].addr, mac_addr);
+	for (i = 1; i < n_addresses; i++) {
+		ether_addr_copy(addresses[i].addr, mac_addr);
+		/* set Local Administered Address bit */
+		addresses[i].addr[0] |= 0x2;
+
+		addresses[i].addr[0] += i << 4;
+	}
+
+	ah->hw->wiphy->addresses = addresses;
+	ah->hw->wiphy->n_addresses = n_addresses;
+}
+
 static void ath12k_mac_hw_unregister(struct ath12k_hw *ah)
 {
 	struct ieee80211_hw *hw = ah->hw;
@@ -14762,6 +14810,7 @@ static void ath12k_mac_hw_unregister(struct ath12k_hw *ah)
 		ath12k_mac_cleanup_unregister(ar);
 
 	ath12k_mac_cleanup_iface_combinations(ah);
+	ath12k_mac_cleanup_mac_address_list(ah);
 
 	SET_IEEE80211_DEV(hw, NULL);
 }
@@ -14878,6 +14927,7 @@ static int ath12k_mac_hw_register(struct ath12k_hw *ah)
 	wiphy->available_antennas_tx = antennas_tx;
 
 	SET_IEEE80211_PERM_ADDR(hw, mac_addr);
+	ath12k_mac_setup_mac_address_list(ah, mac_addr);
 	SET_IEEE80211_DEV(hw, ab->dev);
 
 	ret = ath12k_mac_setup_iface_combinations(ah);
@@ -15120,6 +15170,8 @@ static int ath12k_mac_hw_register(struct ath12k_hw *ah)
 		ath12k_mac_cleanup_unregister(ar);
 	}
 
+	ath12k_mac_cleanup_mac_address_list(ah);
+
 	SET_IEEE80211_DEV(hw, NULL);
 
 	return ret;
diff --git a/drivers/net/wireless/ath/ath12k/wifi7/hw.c b/drivers/net/wireless/ath/ath12k/wifi7/hw.c
index a20c21807344..8658828ea47d 100644
--- a/drivers/net/wireless/ath/ath12k/wifi7/hw.c
+++ b/drivers/net/wireless/ath/ath12k/wifi7/hw.c
@@ -445,6 +445,7 @@ static const struct ath12k_hw_params ath12k_wifi7_hw_params[] = {
 		},
 
 		.host_alloc_ml_id = true,
+		.host_alloc_iface_mac = false,
 	},
 	{
 		.name = "wcn7850 hw2.0",
@@ -539,6 +540,7 @@ static const struct ath12k_hw_params ath12k_wifi7_hw_params[] = {
 		},
 
 		.host_alloc_ml_id = false,
+		.host_alloc_iface_mac = true,
 	},
 	{
 		.name = "qcn9274 hw2.0",
@@ -629,6 +631,7 @@ static const struct ath12k_hw_params ath12k_wifi7_hw_params[] = {
 		},
 
 		.host_alloc_ml_id = true,
+		.host_alloc_iface_mac = false,
 	},
 	{
 		.name = "ipq5332 hw1.0",
@@ -713,6 +716,7 @@ static const struct ath12k_hw_params ath12k_wifi7_hw_params[] = {
 		},
 
 		.host_alloc_ml_id = true,
+		.host_alloc_iface_mac = false,
 	},
 	{
 		.name = "qcc2072 hw1.0",
@@ -808,6 +812,7 @@ static const struct ath12k_hw_params ath12k_wifi7_hw_params[] = {
 		},
 
 		.host_alloc_ml_id = false,
+		.host_alloc_iface_mac = false,
 	},
 	{
 		.name = "ipq5424 hw1.0",
@@ -895,6 +900,7 @@ static const struct ath12k_hw_params ath12k_wifi7_hw_params[] = {
 		},
 
 		.host_alloc_ml_id = true,
+		.host_alloc_iface_mac = false,
 	},
 };
 
-- 
2.55.0