wifi: wilc1000: read MAC address from fuse at probe

The default netdev interface exposed by WILC1000 is registered at probe,
but the chip mac address is not known until ndo_open, which will load and
start chip firmware and then retrieve stored MAC address from it. As a
consequence, the interface has uninitialized value (00:00:00:00:00) until a
user brings up the interface.

Fix MAC address at probe by setting the following steps:
- at probe, read MAC address directly from fuse
- whenever a new netdevice is created, apply saved mac address (which can
  be a user-provided address, or the eFuse Mac address if no address has
  been passed by user)
- whenever an interface is brought up for the first time (and so the
  firmware is loaded and started), enforce netdevice mac address to the
  chip (in case user has changed it)

Reported-by: Heiko Thiery <heiko.thiery@gmail.com>
Closes: https://lore.kernel.org/netdev/CAEyMn7aV-B4OEhHR4Ad0LM3sKCz1-nDqSb9uZNmRWR-hMZ=z+A@mail.gmail.com/T/
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Co-developed-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Tested-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240514-mac_addr_at_probe-v2-6-afef09f1cd10@bootlin.com

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index add0e70a09ea..5ff940c53ad9 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -250,6 +250,12 @@ static int wilc_bus_probe(struct spi_device *spi)
 	if (ret)
 		goto power_down;
 
+	ret = wilc_load_mac_from_nv(wilc);
+	if (ret) {
+		pr_err("Can not retrieve MAC address from chip\n");
+		goto power_down;
+	}
+
 	wilc_wlan_power(wilc, false);
 	vif = wilc_netdev_ifc_init(wilc, "wlan%d", WILC_STATION_MODE,
 				   NL80211_IFTYPE_STATION, false);