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Commit 56faacd0 authored by Felix Fietkau's avatar Felix Fietkau Committed by David S. Miller
Browse files

bgmac: simplify/optimize rx DMA error handling 



Allocate a new buffer before processing the completed one. If allocation
fails, reuse the old buffer.

Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
Acked-by: default avatarRafał Miłecki <zajec5@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4b62dce4

drivers/net/ethernet/broadcom/bgmac.c

+34 −37
Original line number Diff line number Diff line
@@ -386,6 +386,19 @@ static void bgmac_dma_rx_setup_desc(struct bgmac *bgmac, 
	dma_desc->ctl1 = cpu_to_le32(ctl1);

}



static void bgmac_dma_rx_poison_buf(struct device *dma_dev,

				    struct bgmac_slot_info *slot)

{

	struct bgmac_rx_header *rx = slot->buf + BGMAC_RX_BUF_OFFSET;



	dma_sync_single_for_cpu(dma_dev, slot->dma_addr, BGMAC_RX_BUF_SIZE,

				DMA_FROM_DEVICE);

	rx->len = cpu_to_le16(0xdead);

	rx->flags = cpu_to_le16(0xbeef);

	dma_sync_single_for_device(dma_dev, slot->dma_addr, BGMAC_RX_BUF_SIZE,

				   DMA_FROM_DEVICE);

}



static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring,

			     int weight)

{
@@ -406,53 +419,35 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring, 
		struct bgmac_rx_header *rx = slot->buf + BGMAC_RX_BUF_OFFSET;

		struct sk_buff *skb;

		void *buf = slot->buf;

		dma_addr_t dma_addr = slot->dma_addr;

		u16 len, flags;



		do {

			/* Prepare new skb as replacement */

			if (bgmac_dma_rx_skb_for_slot(bgmac, slot)) {

				bgmac_dma_rx_poison_buf(dma_dev, slot);

				break;

			}



			/* Unmap buffer to make it accessible to the CPU */

		dma_sync_single_for_cpu(dma_dev, slot->dma_addr,

			dma_unmap_single(dma_dev, dma_addr,

					 BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);



			/* Get info from the header */

			len = le16_to_cpu(rx->len);

			flags = le16_to_cpu(rx->flags);



		do {

			dma_addr_t old_dma_addr = slot->dma_addr;

			int err;



			/* Check for poison and drop or pass the packet */

			if (len == 0xdead && flags == 0xbeef) {

				bgmac_err(bgmac, "Found poisoned packet at slot %d, DMA issue!\n",

					  ring->start);

				dma_sync_single_for_device(dma_dev,

							   slot->dma_addr,

							   BGMAC_RX_BUF_SIZE,

							   DMA_FROM_DEVICE);

				put_page(virt_to_head_page(buf));

				break;

			}



			/* Omit CRC. */

			len -= ETH_FCS_LEN;



			/* Prepare new skb as replacement */

			err = bgmac_dma_rx_skb_for_slot(bgmac, slot);

			if (err) {

				/* Poison the old skb */

				rx->len = cpu_to_le16(0xdead);

				rx->flags = cpu_to_le16(0xbeef);



				dma_sync_single_for_device(dma_dev,

							   slot->dma_addr,

							   BGMAC_RX_BUF_SIZE,

							   DMA_FROM_DEVICE);

				break;

			}

			bgmac_dma_rx_setup_desc(bgmac, ring, ring->start);



			/* Unmap old skb, we'll pass it to the netfif */

			dma_unmap_single(dma_dev, old_dma_addr,

					 BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);



			skb = build_skb(buf, BGMAC_RX_ALLOC_SIZE);

			skb_put(skb, BGMAC_RX_FRAME_OFFSET +

				BGMAC_RX_BUF_OFFSET + len);
@@ -465,6 +460,8 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring, 
			handled++;

		} while (0);



		bgmac_dma_rx_setup_desc(bgmac, ring, ring->start);



		if (++ring->start >= BGMAC_RX_RING_SLOTS)

			ring->start = 0;
@@ -532,14 +529,14 @@ static void bgmac_dma_rx_ring_free(struct bgmac *bgmac, 


	for (i = 0; i < ring->num_slots; i++) {

		slot = &ring->slots[i];

		if (!slot->buf)

		if (!slot->dma_addr)

			continue;



		if (slot->dma_addr)

		dma_unmap_single(dma_dev, slot->dma_addr,

				 BGMAC_RX_BUF_SIZE,

				 DMA_FROM_DEVICE);

		put_page(virt_to_head_page(slot->buf));

		slot->dma_addr = 0;

	}

}