From 3ee54a07d34fd9b5c34bb1488113fb32be58e38f Mon Sep 17 00:00:00 2001 From: Ivo van Doorn Date: Fri, 29 Aug 2008 21:04:50 +0200 Subject: rt2x00: Map extra_tx_headroom to DMA If a driver requests additional headroom it should be mapped to DMA as well because it will be send to the hardware as well (as form of extra descriptor). Signed-off-by: Ivo van Doorn Signed-off-by: John W. Linville --- drivers/net/wireless/rt2x00/rt2x00queue.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.c b/drivers/net/wireless/rt2x00/rt2x00queue.c index d10a8012f38..2822684c505 100644 --- a/drivers/net/wireless/rt2x00/rt2x00queue.c +++ b/drivers/net/wireless/rt2x00/rt2x00queue.c @@ -100,8 +100,21 @@ void rt2x00queue_map_txskb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb) { struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb); - skbdesc->skb_dma = dma_map_single(rt2x00dev->dev, skb->data, skb->len, - DMA_TO_DEVICE); + /* + * If device has requested headroom, we should make sure that + * is also mapped to the DMA so it can be used for transfering + * additional descriptor information to the hardware. + */ + skb_push(skb, rt2x00dev->hw->extra_tx_headroom); + + skbdesc->skb_dma = + dma_map_single(rt2x00dev->dev, skb->data, skb->len, DMA_TO_DEVICE); + + /* + * Restore data pointer to original location again. + */ + skb_pull(skb, rt2x00dev->hw->extra_tx_headroom); + skbdesc->flags |= SKBDESC_DMA_MAPPED_TX; } EXPORT_SYMBOL_GPL(rt2x00queue_map_txskb); @@ -117,7 +130,12 @@ void rt2x00queue_unmap_skb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb) } if (skbdesc->flags & SKBDESC_DMA_MAPPED_TX) { - dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma, skb->len, + /* + * Add headroom to the skb length, it has been removed + * by the driver, but it was actually mapped to DMA. + */ + dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma, + skb->len + rt2x00dev->hw->extra_tx_headroom, DMA_TO_DEVICE); skbdesc->flags &= ~SKBDESC_DMA_MAPPED_TX; } -- cgit v1.2.3