mt76: mt7615: add support for mtd eeprom parsing

Calibration data are often available on a specific mtd partition on
embedded devices. Take into account eeprom calibration data if
available.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/eeprom.c b/drivers/net/wireless/mediatek/mt76/mt7615/eeprom.c
index dd5ab46..1712f66 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7615/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/eeprom.c
@@ -42,13 +42,13 @@ static int mt7615_efuse_read(struct mt7615_dev *dev, u32 base,
 
 static int mt7615_efuse_init(struct mt7615_dev *dev)
 {
-       u32 base = mt7615_reg_map(dev, MT_EFUSE_BASE);
-       int len = MT7615_EEPROM_SIZE;
-       int ret, i;
+       u32 val, base = mt7615_reg_map(dev, MT_EFUSE_BASE);
+       int i, len = MT7615_EEPROM_SIZE;
        void *buf;
 
-       if (mt76_rr(dev, base + MT_EFUSE_BASE_CTRL) & MT_EFUSE_BASE_CTRL_EMPTY)
-               return -EINVAL;
+       val = mt76_rr(dev, base + MT_EFUSE_BASE_CTRL);
+       if (val & MT_EFUSE_BASE_CTRL_EMPTY)
+               return 0;
 
        dev->mt76.otp.data = devm_kzalloc(dev->mt76.dev, len, GFP_KERNEL);
        dev->mt76.otp.size = len;
@@ -57,6 +57,8 @@ static int mt7615_efuse_init(struct mt7615_dev *dev)
 
        buf = dev->mt76.otp.data;
        for (i = 0; i + 16 <= len; i += 16) {
+               int ret;
+
                ret = mt7615_efuse_read(dev, base, i, buf + i);
                if (ret)
                        return ret;
@@ -76,6 +78,18 @@ static int mt7615_eeprom_load(struct mt7615_dev *dev)
        return mt7615_efuse_init(dev);
 }
 
+static int mt7615_check_eeprom(struct mt76_dev *dev)
+{
+       u16 val = get_unaligned_le16(dev->eeprom.data);
+
+       switch (val) {
+       case 0x7615:
+               return 0;
+       default:
+               return -EINVAL;
+       }
+}
+
 int mt7615_eeprom_init(struct mt7615_dev *dev)
 {
        int ret;
@@ -84,7 +98,10 @@ int mt7615_eeprom_init(struct mt7615_dev *dev)
        if (ret < 0)
                return ret;
 
-       memcpy(dev->mt76.eeprom.data, dev->mt76.otp.data, MT7615_EEPROM_SIZE);
+       ret = mt7615_check_eeprom(&dev->mt76);
+       if (ret && dev->mt76.otp.data)
+               memcpy(dev->mt76.eeprom.data, dev->mt76.otp.data,
+                      MT7615_EEPROM_SIZE);
 
        dev->mt76.cap.has_2ghz = true;
        dev->mt76.cap.has_5ghz = true;