[PATCH ath-next] 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.

Handle only single-radio wiphys. Wiphys with more than one radio behave
exactly as before.

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

Signed-off-by: Vitor Soares <vitor.soares@toradex.com>
---
Note that a device which is not MLO capable registers one wiphy per
radio, so each radio of a multi-radio device also gets a pool, seeded
from that radio's own MAC. I only have single-radio WCN7850 hardware,
so that case is untested.
---
 drivers/net/wireless/ath/ath12k/mac.c | 48 +++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index 9a775602775d..bee6701f1029 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -14685,6 +14685,50 @@ 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 ath12k *ar = ath12k_ah_to_ar(ah, 0);
+	struct mac_address *addresses;
+	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;
+
+	/* 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;
@@ -14704,6 +14748,7 @@ 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);
 }
@@ -14820,6 +14865,7 @@ 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);
@@ -15041,6 +15087,8 @@ 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;
-- 
2.55.0