[PATCH RFC 4/5] wifi: ath12k: Support MAC address from the firmware node

[Abel Vesa]

Read a MAC address from the device's firmware node (a DT "mac-address"/
"local-mac-address" property, or an nvmem cell named "mac-address" via
device_get_mac_address()), and use it in preference to the address from
the firmware board data. This mirrors what ath10k and ath11k already do
and lets the WLAN MAC be sourced from firmware-provisioned storage such
as a UEFI variable exposed through nvmem.

A device tree / nvmem address takes precedence over the board-data MAC,
so an explicitly provisioned address wins even when the firmware reports
a valid per-pdev address. An all-zero (absent) address is ignored.

Note: the provisioned address must be a valid unicast MAC; a multicast
address (odd first octet) is rejected by nvmem_get_mac_address().

Assisted-by: LLM
Signed-off-by: Abel Vesa <abel.vesa at oss.qualcomm.com>
---
 drivers/net/wireless/ath/ath12k/mac.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index 01f8c6572f65..f4d2d0377c8e 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -14878,15 +14878,27 @@ static int ath12k_mac_hw_register(struct ath12k_hw *ah)
 	u32 ht_cap = U32_MAX, antennas_rx = 0, antennas_tx = 0;
 	bool is_6ghz = false, is_raw_mode = false, is_monitor_disable = false;
 	u8 *mac_addr = NULL;
+	u8 mac_from_dt[ETH_ALEN] = {};
 	u8 mbssid_max_interfaces = 0;
 
 	wiphy->max_ap_assoc_sta = 0;
 
+	/*
+	 * Allow a MAC address provided through the device tree (directly or
+	 * via an nvmem cell named "mac-address") to override the one from the
+	 * firmware board data.
+	 */
+	device_get_mac_address(ab->dev, mac_from_dt);
+
 	for_each_ar(ah, ar, i) {
 		u32 ht_cap_info = 0;
 
 		pdev = ar->pdev;
-		if (ar->ab->pdevs_macaddr_valid) {
+		if (!is_zero_ether_addr(mac_from_dt)) {
+			/* A device tree / nvmem address takes precedence. */
+			ether_addr_copy(ar->mac_addr, mac_from_dt);
+			ar->mac_addr[4] += ar->pdev_idx;
+		} else if (ar->ab->pdevs_macaddr_valid) {
 			ether_addr_copy(ar->mac_addr, pdev->mac_addr);
 		} else {
 			ether_addr_copy(ar->mac_addr, ar->ab->mac_addr);

-- 
2.54.0