From 56faacd04509f0a60ed646473a930fe584f1cb02 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 14 Apr 2015 12:07:57 +0200 Subject: [PATCH] bgmac: simplify/optimize rx DMA error handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Allocate a new buffer before processing the completed one. If allocation fails, reuse the old buffer. Signed-off-by: Felix Fietkau Acked-by: Rafał Miłecki Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bgmac.c | 73 +++++++++++++-------------- 1 file changed, 35 insertions(+), 38 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c index 424a68ce5aa0..60b5c3ca8551 100644 --- a/drivers/net/ethernet/broadcom/bgmac.c +++ b/drivers/net/ethernet/broadcom/bgmac.c @@ -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; - /* Unmap buffer to make it accessible to the CPU */ - dma_sync_single_for_cpu(dma_dev, slot->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; + /* 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_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); /* 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); + 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; } }