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From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 12 Apr 2015 22:23:07 +0200
Subject: [PATCH] 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: Felix Fietkau <nbd@nbd.name>
---
--- 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(stru
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 bgma
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 bgma
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(struc
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;
}
}
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