mt76: mt7915: add support for flash mode

Add support for getting rf values from flash.
This is used for some test purposes and products.
If the mtd partition is configured in dts, driver will read from flash
to init eeprom command; if not, still init it with efuse's values.

An example:
&slot0 {
	mt7915@0,0 {
		reg = <0x0000 0 0 0 0>;
		device_type = "pci";
		mediatek,mtd-eeprom = <&factory 0x0000>;
	};
};
Acked-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7915/eeprom.c

@@ -22,7 +22,10 @@ static int mt7915_eeprom_load(struct mt7915_dev *dev)
 	if (ret < 0)
 		return ret;
 
-	memset(dev->mt76.eeprom.data, -1, MT7915_EEPROM_SIZE);
+	if (ret)
+		dev->flash_mode = true;
+	else
+		memset(dev->mt76.eeprom.data, -1, MT7915_EEPROM_SIZE);
 
 	return 0;
 }

drivers/net/wireless/mediatek/mt76/mt7915/mcu.c

@@ -3237,17 +3237,57 @@ int mt7915_mcu_set_chan_info(struct mt7915_phy *phy, int cmd)
 	return mt76_mcu_send_msg(&dev->mt76, cmd, &req, sizeof(req), true);
 }
 
+static int mt7915_mcu_set_eeprom_flash(struct mt7915_dev *dev)
+{
+#define TOTAL_PAGE_MASK		GENMASK(7, 5)
+#define PAGE_IDX_MASK		GENMASK(4, 2)
+#define PER_PAGE_SIZE		0x400
+	struct mt7915_mcu_eeprom req = { .buffer_mode = EE_MODE_BUFFER };
+	u8 total = MT7915_EEPROM_SIZE / PER_PAGE_SIZE;
+	u8 *eep = (u8 *)dev->mt76.eeprom.data;
+	int eep_len;
+	int i;
+
+	for (i = 0; i <= total; i++, eep += eep_len) {
+		struct sk_buff *skb;
+		int ret;
+
+		if (i == total)
+			eep_len = MT7915_EEPROM_SIZE % PER_PAGE_SIZE;
+		else
+			eep_len = PER_PAGE_SIZE;
+
+		skb = mt76_mcu_msg_alloc(&dev->mt76, NULL,
+					 sizeof(req) + eep_len);
+		if (!skb)
+			return -ENOMEM;
+
+		req.format = FIELD_PREP(TOTAL_PAGE_MASK, total) |
+			     FIELD_PREP(PAGE_IDX_MASK, i) | EE_FORMAT_WHOLE;
+		req.len = cpu_to_le16(eep_len);
+
+		skb_put_data(skb, &req, sizeof(req));
+		skb_put_data(skb, eep, eep_len);
+
+		ret = mt76_mcu_skb_send_msg(&dev->mt76, skb,
+					    MCU_EXT_CMD_EFUSE_BUFFER_MODE, true);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 int mt7915_mcu_set_eeprom(struct mt7915_dev *dev)
 {
-	struct req_hdr {
-		u8 buffer_mode;
-		u8 format;
-		__le16 len;
-	} __packed req = {
+	struct mt7915_mcu_eeprom req = {
 		.buffer_mode = EE_MODE_EFUSE,
 		.format = EE_FORMAT_WHOLE,
 	};
 
+	if (dev->flash_mode)
+		return mt7915_mcu_set_eeprom_flash(dev);
+
 	return mt76_mcu_send_msg(&dev->mt76, MCU_EXT_CMD_EFUSE_BUFFER_MODE,
 				 &req, sizeof(req), true);
 }

drivers/net/wireless/mediatek/mt76/mt7915/mcu.h

@@ -118,6 +118,12 @@ struct mt7915_mcu_rdd_report {
 	} hw_pulse[32];
 } __packed;
 
+struct mt7915_mcu_eeprom {
+	u8 buffer_mode;
+	u8 format;
+	__le16 len;
+} __packed;
+
 struct mt7915_mcu_eeprom_info {
 	__le32 addr;
 	__le32 valid;

drivers/net/wireless/mediatek/mt76/mt7915/mt7915.h

@@ -175,6 +175,7 @@ struct mt7915_dev {
 	s8 **rate_power; /* TODO: use mt76_rate_power */
 
 	bool dbdc_support;
+	bool flash_mode;
 	bool fw_debug;
 
 #ifdef CONFIG_NL80211_TESTMODE