wifi: mt76: fix rx checksum offload on mt7615/mt7915/mt7921

Checking the relevant rxd bits for the checksum information only indicates
if the checksum verification was performed by the hardware and doesn't show
actual checksum errors. Checksum errors are indicated in the info field of
the DMA descriptor. Fix packets erroneously marked as CHECKSUM_UNNECESSARY
by checking the extra bits as well.
Those bits are only passed to the driver for MMIO devices at the moment, so
limit checksum offload to those.

Fixes: 2122dfbfd0bd ("mt76: mt7615: add rx checksum offload support")
Fixes: 94244d2ea503 ("mt76: mt7915: add rx checksum offload support")
Fixes: 0e75732764e8 ("mt76: mt7921: enable rx csum offload")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221005130824.23371-2-nbd@nbd.name

4 files changed, 10 insertions, 7 deletions

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index 4901aa02b4fb..7378c4d1e156 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -696,10 +696,7 @@ mt76_dma_rx_process(struct mt76_dev *dev, struct mt76_queue *q, int budget)
 
 		skb_reserve(skb, q->buf_offset);
 
-		if (q == &dev->q_rx[MT_RXQ_MCU]) {
-			u32 *rxfce = (u32 *)skb->cb;
-			*rxfce = info;
-		}
+		*(u32 *)skb->cb = info;
 
 		__skb_put(skb, len);
 		done++;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
index cbc6859e38ac..2ce1705c0f43 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/mac.c
@@ -345,6 +345,7 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 	u32 rxd1 = le32_to_cpu(rxd[1]);
 	u32 rxd2 = le32_to_cpu(rxd[2]);
 	u32 csum_mask = MT_RXD0_NORMAL_IP_SUM | MT_RXD0_NORMAL_UDP_TCP_SUM;
+	u32 csum_status = *(u32 *)skb->cb;
 	bool unicast, hdr_trans, remove_pad, insert_ccmp_hdr = false;
 	u16 hdr_gap;
 	int phy_idx;
@@ -394,7 +395,8 @@ static int mt7615_mac_fill_rx(struct mt7615_dev *dev, struct sk_buff *skb)
 		spin_unlock_bh(&dev->sta_poll_lock);
 	}
 
-	if ((rxd0 & csum_mask) == csum_mask)
+	if (mt76_is_mmio(&dev->mt76) && (rxd0 & csum_mask) == csum_mask &&
+	    !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (rxd2 & MT_RXD2_NORMAL_FCS_ERR)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index e32092f67ea1..a4bcc617c1a3 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -233,6 +233,7 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 	u8 remove_pad, amsdu_info;
 	u8 mode = 0, qos_ctl = 0;
 	struct mt7915_sta *msta = NULL;
+	u32 csum_status = *(u32 *)skb->cb;
 	bool hdr_trans;
 	u16 hdr_gap;
 	u16 seq_ctrl = 0;
@@ -288,7 +289,8 @@ mt7915_mac_fill_rx(struct mt7915_dev *dev, struct sk_buff *skb)
 	if (!sband->channels)
 		return -EINVAL;
 
-	if ((rxd0 & csum_mask) == csum_mask)
+	if ((rxd0 & csum_mask) == csum_mask &&
+	    !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (rxd1 & MT_RXD1_NORMAL_FCS_ERR)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index e4868c492bc0..650ab97ae052 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -230,6 +230,7 @@ mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 	struct mt76_phy *mphy = &dev->mt76.phy;
 	struct mt7921_phy *phy = &dev->phy;
 	struct ieee80211_supported_band *sband;
+	u32 csum_status = *(u32 *)skb->cb;
 	u32 rxd0 = le32_to_cpu(rxd[0]);
 	u32 rxd1 = le32_to_cpu(rxd[1]);
 	u32 rxd2 = le32_to_cpu(rxd[2]);
@@ -290,7 +291,8 @@ mt7921_mac_fill_rx(struct mt7921_dev *dev, struct sk_buff *skb)
 	if (!sband->channels)
 		return -EINVAL;
 
-	if ((rxd0 & csum_mask) == csum_mask)
+	if (mt76_is_mmio(&dev->mt76) && (rxd0 & csum_mask) == csum_mask &&
+	    !(csum_status & (BIT(0) | BIT(2) | BIT(3))))
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
 	if (rxd1 & MT_RXD1_NORMAL_FCS_ERR)