[PATCH 1/3] wifi: mt76: mt7996: extend flexibility of mt7996_mcu_get_eeprom()

[Shayne Chen]

Support passing customized buffer pointer and length to
mt7996_mcu_get_eeprom().

This is the preparation for adding more variants support which needs to
prefetch FEM module from efuse, and also fixes potential OOB issue when
reading the last efuse block.

Co-developed-by: StanleyYP Wang <StanleyYP.Wang at mediatek.com>
Signed-off-by: StanleyYP Wang <StanleyYP.Wang at mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen at mediatek.com>
---
 drivers/net/wireless/mediatek/mt76/mt7996/eeprom.c |  9 +++++++--
 drivers/net/wireless/mediatek/mt76/mt7996/mcu.c    | 14 ++++++++++----
 drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h |  2 +-
 3 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/eeprom.c b/drivers/net/wireless/mediatek/mt76/mt7996/eeprom.c
index 4a8237118287..861aba68a725 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/eeprom.c
@@ -86,8 +86,13 @@ static int mt7996_eeprom_load(struct mt7996_dev *dev)
 		/* read eeprom data from efuse */
 		block_num = DIV_ROUND_UP(MT7996_EEPROM_SIZE, eeprom_blk_size);
 		for (i = 0; i < block_num; i++) {
-			ret = mt7996_mcu_get_eeprom(dev, i * eeprom_blk_size);
-			if (ret < 0)
+			u32 len = eeprom_blk_size;
+
+			if (i == block_num - 1)
+				len = MT7996_EEPROM_SIZE % eeprom_blk_size;
+			ret = mt7996_mcu_get_eeprom(dev, i * eeprom_blk_size,
+						    NULL, len);
+			if (ret && ret != -EINVAL)
 				return ret;
 		}
 	}
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c
index 327337b31279..fa7832f625d7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c
@@ -3548,7 +3548,7 @@ int mt7996_mcu_set_eeprom(struct mt7996_dev *dev)
 				 &req, sizeof(req), true);
 }
 
-int mt7996_mcu_get_eeprom(struct mt7996_dev *dev, u32 offset)
+int mt7996_mcu_get_eeprom(struct mt7996_dev *dev, u32 offset, u8 *buf, u32 buf_len)
 {
 	struct {
 		u8 _rsv[4];
@@ -3577,15 +3577,21 @@ int mt7996_mcu_get_eeprom(struct mt7996_dev *dev, u32 offset)
 	valid = le32_to_cpu(*(__le32 *)(skb->data + 16));
 	if (valid) {
 		u32 addr = le32_to_cpu(*(__le32 *)(skb->data + 12));
-		u8 *buf = (u8 *)dev->mt76.eeprom.data + addr;
+
+		if (!buf)
+			buf = (u8 *)dev->mt76.eeprom.data + addr;
+		if (!buf_len || buf_len > MT7996_EEPROM_BLOCK_SIZE)
+			buf_len = MT7996_EEPROM_BLOCK_SIZE;
 
 		skb_pull(skb, 48);
-		memcpy(buf, skb->data, MT7996_EEPROM_BLOCK_SIZE);
+		memcpy(buf, skb->data, buf_len);
+	} else {
+		ret = -EINVAL;
 	}
 
 	dev_kfree_skb(skb);
 
-	return 0;
+	return ret;
 }
 
 int mt7996_mcu_get_eeprom_free_block(struct mt7996_dev *dev, u8 *block_num)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h b/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
index ab8c9070630b..55aa5f6ab77d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mt7996.h
@@ -476,7 +476,7 @@ int mt7996_mcu_set_fixed_rate_ctrl(struct mt7996_dev *dev,
 int mt7996_mcu_set_fixed_field(struct mt7996_dev *dev, struct ieee80211_vif *vif,
 			       struct ieee80211_sta *sta, void *data, u32 field);
 int mt7996_mcu_set_eeprom(struct mt7996_dev *dev);
-int mt7996_mcu_get_eeprom(struct mt7996_dev *dev, u32 offset);
+int mt7996_mcu_get_eeprom(struct mt7996_dev *dev, u32 offset, u8 *buf, u32 buf_len);
 int mt7996_mcu_get_eeprom_free_block(struct mt7996_dev *dev, u8 *block_num);
 int mt7996_mcu_get_chip_config(struct mt7996_dev *dev, u32 *cap);
 int mt7996_mcu_set_ser(struct mt7996_dev *dev, u8 action, u8 set, u8 band);
-- 
2.39.2