2022-10-03 09:46:59

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH 2/4] wifi: mt76: dma: add support for mapping skb fragments

Only supported for skbs without frag_list. This is needed to support
scatter/gather for packets on WLAN devices with A-MSDU offload

Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/mediatek/mt76/dma.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index 4901aa02b4fb..ceb63b3aaced 100644
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -359,12 +359,17 @@ mt76_dma_tx_queue_skb(struct mt76_dev *dev, struct mt76_queue *q,
.skb = skb,
};
struct ieee80211_hw *hw;
- int len, n = 0, ret = -ENOMEM;
+ int len, i, n = 0, ret = -ENOMEM;
struct mt76_txwi_cache *t;
struct sk_buff *iter;
dma_addr_t addr;
u8 *txwi;

+ if (skb_shinfo(skb)->nr_frags &&
+ skb_shinfo(skb)->nr_frags + 1 > dev->hw->max_tx_fragments &&
+ skb_linearize(skb))
+ goto free_skb;
+
t = mt76_get_txwi(dev);
if (!t)
goto free_skb;
@@ -385,6 +390,22 @@ mt76_dma_tx_queue_skb(struct mt76_dev *dev, struct mt76_queue *q,
tx_info.buf[n].addr = addr;
tx_info.buf[n++].len = len;

+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+ skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+ if (n == ARRAY_SIZE(tx_info.buf))
+ goto unmap;
+
+ len = skb_frag_size(frag);
+ addr = skb_frag_dma_map(dev->dma_dev, frag, 0, len,
+ DMA_TO_DEVICE);
+ if (unlikely(dma_mapping_error(dev->dma_dev, addr)))
+ goto unmap;
+
+ tx_info.buf[n].addr = addr;
+ tx_info.buf[n++].len = len;
+ }
+
skb_walk_frags(skb, iter) {
if (n == ARRAY_SIZE(tx_info.buf))
goto unmap;
--
2.36.1