netdev - [PATCH 5/6] wl1251: Parse and use MAC address from supplied NVS data

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Message-Id: <1482598381-16513-6-git-send-email-pali.rohar@gmail.com>
Date:   Sat, 24 Dec 2016 17:53:00 +0100
From:   Pali Rohár <pali.rohar@...il.com>
To:     Ming Lei <ming.lei@...onical.com>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kalle Valo <kvalo@...eaurora.org>,
        David Gnedt <david.gnedt@...izone.at>,
        Michal Kazior <michal.kazior@...to.com>,
        Daniel Wagner <wagi@...om.org>,
        Tony Lindgren <tony@...mide.com>,
        Sebastian Reichel <sre@...nel.org>,
        Pavel Machek <pavel@....cz>,
        Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
        Aaro Koskinen <aaro.koskinen@....fi>,
        Grazvydas Ignotas <notasas@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org,
        Pali Rohár <pali.rohar@...il.com>
Subject: [PATCH 5/6] wl1251: Parse and use MAC address from supplied NVS data

This patch implements parsing MAC address from NVS data which are sent to
wl1251 chip. Calibration NVS data could contain valid MAC address and it
will be used instead randomly generated.

This patch also move code for requesting NVS data from userspace to driver
initialization code to make sure that NVS data will be there at time when
permanent MAC address is needed.

Calibration NVS data for wl1251 are model specific. Every one device with
wl1251 chip should have been calibrated in factory and needs to provide own
calibration data.

Default example wl1251-nvs.bin data found in linux-firmware repository and
contains MAC address 00:00:20:07:03:09. So this MAC address is marked as
invalid as it is not real device specific address, just example one.

Format of calibration NVS data can be found at:
http://notaz.gp2x.de/misc/pnd/wl1251/nvs_map.txt

Signed-off-by: Pali Rohár <pali.rohar@...il.com>
---
 drivers/net/wireless/ti/wl1251/main.c |   39 ++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c
index c3fa0b6..1454ba2 100644
--- a/drivers/net/wireless/ti/wl1251/main.c
+++ b/drivers/net/wireless/ti/wl1251/main.c
@@ -205,13 +205,6 @@ static int wl1251_chip_wakeup(struct wl1251 *wl)
 			goto out;
 	}
 
-	if (wl->nvs == NULL && !wl->use_eeprom) {
-		/* No NVS from netlink, try to get it from the filesystem */
-		ret = wl1251_fetch_nvs(wl);
-		if (ret < 0)
-			goto out;
-	}
-
 out:
 	return ret;
 }
@@ -1538,6 +1531,30 @@ static int wl1251_read_eeprom_mac(struct wl1251 *wl)
 	return 0;
 }
 
+static int wl1251_read_nvs_mac(struct wl1251 *wl)
+{
+	u8 mac[ETH_ALEN];
+	int i;
+
+	if (wl->nvs_len < 0x24)
+		return -ENODATA;
+
+	/* length is 2 and data address is 0x546c (mask is 0xfffe) */
+	if (wl->nvs[0x19] != 2 || wl->nvs[0x1a] != 0x6d || wl->nvs[0x1b] != 0x54)
+		return -EINVAL;
+
+	/* MAC is stored in reverse order */
+	for (i = 0; i < ETH_ALEN; i++)
+		mac[i] = wl->nvs[0x1c + ETH_ALEN - i - 1];
+
+	/* 00:00:20:07:03:09 is in default example wl1251-nvs.bin, so invalid */
+	if (ether_addr_equal_unaligned(mac, "\x00\x00\x20\x07\x03\x09"))
+		return -EINVAL;
+
+	memcpy(wl->mac_addr, mac, ETH_ALEN);
+	return 0;
+}
+
 static int wl1251_register_hw(struct wl1251 *wl)
 {
 	int ret;
@@ -1581,10 +1598,16 @@ int wl1251_init_ieee80211(struct wl1251 *wl)
 
 	wl->hw->queues = 4;
 
+	if (wl->nvs == NULL && !wl->use_eeprom) {
+		ret = wl1251_fetch_nvs(wl);
+		if (ret < 0)
+			goto out;
+	}
+
 	if (wl->use_eeprom)
 		ret = wl1251_read_eeprom_mac(wl);
 	else
-		ret = -EINVAL;
+		ret = wl1251_read_nvs_mac(wl);
 
 	if (ret == 0 && !is_valid_ether_addr(wl->mac_addr))
 		ret = -EINVAL;
-- 
1.7.9.5