131 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			131 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From: Felix Fietkau <nbd@openwrt.org>
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Date: Sun, 12 Apr 2015 22:23:07 +0200
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Subject: [PATCH] bgmac: simplify/optimize rx DMA error handling
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Allocate a new buffer before processing the completed one. If allocation
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fails, reuse the old buffer.
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Signed-off-by: Felix Fietkau <nbd@openwrt.org>
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---
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--- a/drivers/net/ethernet/broadcom/bgmac.c
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+++ b/drivers/net/ethernet/broadcom/bgmac.c
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@@ -386,6 +386,19 @@ static void bgmac_dma_rx_setup_desc(stru
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 	dma_desc->ctl1 = cpu_to_le32(ctl1);
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 }
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+static void bgmac_dma_rx_poison_buf(struct device *dma_dev,
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+				    struct bgmac_slot_info *slot)
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+{
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+	struct bgmac_rx_header *rx = slot->buf + BGMAC_RX_BUF_OFFSET;
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+
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+	dma_sync_single_for_cpu(dma_dev, slot->dma_addr, BGMAC_RX_BUF_SIZE,
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+				DMA_FROM_DEVICE);
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+	rx->len = cpu_to_le16(0xdead);
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+	rx->flags = cpu_to_le16(0xbeef);
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+	dma_sync_single_for_device(dma_dev, slot->dma_addr, BGMAC_RX_BUF_SIZE,
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+				   DMA_FROM_DEVICE);
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+}
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+
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 static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring,
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 			     int weight)
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 {
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@@ -406,53 +419,35 @@ static int bgmac_dma_rx_read(struct bgma
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 		struct bgmac_rx_header *rx = slot->buf + BGMAC_RX_BUF_OFFSET;
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 		struct sk_buff *skb;
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 		void *buf = slot->buf;
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+		dma_addr_t dma_addr = slot->dma_addr;
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 		u16 len, flags;
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-		/* Unmap buffer to make it accessible to the CPU */
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-		dma_sync_single_for_cpu(dma_dev, slot->dma_addr,
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-					BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
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-
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-		/* Get info from the header */
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-		len = le16_to_cpu(rx->len);
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-		flags = le16_to_cpu(rx->flags);
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-
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 		do {
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-			dma_addr_t old_dma_addr = slot->dma_addr;
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-			int err;
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+			/* Prepare new skb as replacement */
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+			if (bgmac_dma_rx_skb_for_slot(bgmac, slot)) {
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+				bgmac_dma_rx_poison_buf(dma_dev, slot);
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+				break;
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+			}
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+
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+			/* Unmap buffer to make it accessible to the CPU */
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+			dma_unmap_single(dma_dev, dma_addr,
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+					 BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
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+
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+			/* Get info from the header */
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+			len = le16_to_cpu(rx->len);
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+			flags = le16_to_cpu(rx->flags);
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 			/* Check for poison and drop or pass the packet */
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 			if (len == 0xdead && flags == 0xbeef) {
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 				bgmac_err(bgmac, "Found poisoned packet at slot %d, DMA issue!\n",
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 					  ring->start);
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-				dma_sync_single_for_device(dma_dev,
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-							   slot->dma_addr,
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-							   BGMAC_RX_BUF_SIZE,
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-							   DMA_FROM_DEVICE);
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+				put_page(virt_to_head_page(buf));
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 				break;
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 			}
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 			/* Omit CRC. */
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 			len -= ETH_FCS_LEN;
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-			/* Prepare new skb as replacement */
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-			err = bgmac_dma_rx_skb_for_slot(bgmac, slot);
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-			if (err) {
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-				/* Poison the old skb */
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-				rx->len = cpu_to_le16(0xdead);
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-				rx->flags = cpu_to_le16(0xbeef);
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-
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-				dma_sync_single_for_device(dma_dev,
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-							   slot->dma_addr,
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-							   BGMAC_RX_BUF_SIZE,
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-							   DMA_FROM_DEVICE);
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-				break;
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-			}
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-			bgmac_dma_rx_setup_desc(bgmac, ring, ring->start);
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-
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-			/* Unmap old skb, we'll pass it to the netfif */
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-			dma_unmap_single(dma_dev, old_dma_addr,
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-					 BGMAC_RX_BUF_SIZE, DMA_FROM_DEVICE);
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-
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 			skb = build_skb(buf, BGMAC_RX_ALLOC_SIZE);
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 			skb_put(skb, BGMAC_RX_FRAME_OFFSET +
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 				BGMAC_RX_BUF_OFFSET + len);
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@@ -465,6 +460,8 @@ static int bgmac_dma_rx_read(struct bgma
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 			handled++;
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 		} while (0);
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+		bgmac_dma_rx_setup_desc(bgmac, ring, ring->start);
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+
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 		if (++ring->start >= BGMAC_RX_RING_SLOTS)
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 			ring->start = 0;
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@@ -532,14 +529,14 @@ static void bgmac_dma_rx_ring_free(struc
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 	for (i = 0; i < ring->num_slots; i++) {
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 		slot = &ring->slots[i];
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-		if (!slot->buf)
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+		if (!slot->dma_addr)
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 			continue;
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-		if (slot->dma_addr)
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-			dma_unmap_single(dma_dev, slot->dma_addr,
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-					 BGMAC_RX_BUF_SIZE,
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-					 DMA_FROM_DEVICE);
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+		dma_unmap_single(dma_dev, slot->dma_addr,
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+				 BGMAC_RX_BUF_SIZE,
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+				 DMA_FROM_DEVICE);
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 		put_page(virt_to_head_page(slot->buf));
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+		slot->dma_addr = 0;
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 	}
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 }
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