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-rw-r--r--target/linux/generic/patches-3.18/077-07-bgmac-simplify-rx-DMA-error-handling.patch130
1 files changed, 130 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.18/077-07-bgmac-simplify-rx-DMA-error-handling.patch b/target/linux/generic/patches-3.18/077-07-bgmac-simplify-rx-DMA-error-handling.patch
new file mode 100644
index 0000000..2ca9d10
--- /dev/null
+++ b/target/linux/generic/patches-3.18/077-07-bgmac-simplify-rx-DMA-error-handling.patch
@@ -0,0 +1,130 @@
+From: Felix Fietkau <nbd@openwrt.org>
+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@openwrt.org>
+---
+
+--- 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;
+ }
+ }
+