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Commit abe78717 authored by Lennert Buytenhek's avatar Lennert Buytenhek Committed by Lennert Buytenhek
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mv643xx_eth: enforce multiple-of-8-bytes receive buffer size restriction 



The mv643xx_eth hardware ignores the lower three bits of the buffer
size field in receive descriptors, causing the reception of full-sized
packets to fail at some MTUs.  Fix this by rounding the size of
allocated receive buffers up to a multiple of eight bytes.

While we are at it, add a bit of extra space to each receive buffer so
that we can handle multiple vlan tags on ingress.

Signed-off-by: default avatarLennert Buytenhek <buytenh@marvell.com>
parent 9e1f3772

drivers/net/mv643xx_eth.c

+13 −5
Original line number Diff line number Diff line
@@ -474,11 +474,19 @@ static void rxq_refill(struct rx_queue *rxq) 
		/*

		 * Reserve 2+14 bytes for an ethernet header (the

		 * hardware automatically prepends 2 bytes of dummy

		 * data to each received packet), 4 bytes for a VLAN

		 * header, and 4 bytes for the trailing FCS -- 24

		 * bytes total.

		 * data to each received packet), 16 bytes for up to

		 * four VLAN tags, and 4 bytes for the trailing FCS

		 * -- 36 bytes total.

		 */

		skb_size = mp->dev->mtu + 24;

		skb_size = mp->dev->mtu + 36;



		/*

		 * Make sure that the skb size is a multiple of 8

		 * bytes, as the lower three bits of the receive

		 * descriptor's buffer size field are ignored by

		 * the hardware.

		 */

		skb_size = (skb_size + 7) & ~7;



		skb = dev_alloc_skb(skb_size + dma_get_cache_alignment() - 1);

		if (skb == NULL)
@@ -552,7 +560,7 @@ static int rxq_process(struct rx_queue *rxq, int budget) 
		spin_unlock_irqrestore(&mp->lock, flags);



		dma_unmap_single(NULL, rx_desc->buf_ptr + 2,

				 mp->dev->mtu + 24, DMA_FROM_DEVICE);

				 rx_desc->buf_size, DMA_FROM_DEVICE);

		rxq->rx_desc_count--;

		rx++;