amd-xgbe: Implement split header receive support

Provide support for splitting IP packets so that the header and
payload can be sent to different DMA addresses.  This will allow
the IP header to be put into the linear part of the skb while the
payload can be added as frags.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 113 insertions, 63 deletions

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-desc.c b/drivers/net/ethernet/amd/xgbe/xgbe-desc.c
index 99911f45f334..e6b9f54b9697 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-desc.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-desc.c
@@ -138,15 +138,26 @@ static void xgbe_free_ring(struct xgbe_prv_data *pdata,
 		ring->rdata = NULL;
 	}
 
-	if (ring->rx_pa.pages) {
-		dma_unmap_page(pdata->dev, ring->rx_pa.pages_dma,
-			       ring->rx_pa.pages_len, DMA_FROM_DEVICE);
-		put_page(ring->rx_pa.pages);
-
-		ring->rx_pa.pages = NULL;
-		ring->rx_pa.pages_len = 0;
-		ring->rx_pa.pages_offset = 0;
-		ring->rx_pa.pages_dma = 0;
+	if (ring->rx_hdr_pa.pages) {
+		dma_unmap_page(pdata->dev, ring->rx_hdr_pa.pages_dma,
+			       ring->rx_hdr_pa.pages_len, DMA_FROM_DEVICE);
+		put_page(ring->rx_hdr_pa.pages);
+
+		ring->rx_hdr_pa.pages = NULL;
+		ring->rx_hdr_pa.pages_len = 0;
+		ring->rx_hdr_pa.pages_offset = 0;
+		ring->rx_hdr_pa.pages_dma = 0;
+	}
+
+	if (ring->rx_buf_pa.pages) {
+		dma_unmap_page(pdata->dev, ring->rx_buf_pa.pages_dma,
+			       ring->rx_buf_pa.pages_len, DMA_FROM_DEVICE);
+		put_page(ring->rx_buf_pa.pages);
+
+		ring->rx_buf_pa.pages = NULL;
+		ring->rx_buf_pa.pages_len = 0;
+		ring->rx_buf_pa.pages_offset = 0;
+		ring->rx_buf_pa.pages_dma = 0;
 	}
 
 	if (ring->rdesc) {
@@ -244,62 +255,93 @@ err_ring:
 	return ret;
 }
 
-static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,
-			      struct xgbe_ring *ring,
-			      struct xgbe_ring_data *rdata)
+static int xgbe_alloc_pages(struct xgbe_prv_data *pdata,
+			    struct xgbe_page_alloc *pa, gfp_t gfp, int order)
 {
-	if (!ring->rx_pa.pages) {
-		struct page *pages = NULL;
-		dma_addr_t pages_dma;
-		gfp_t gfp;
-		int order, ret;
-
-		/* Try to obtain pages, decreasing order if necessary */
-		gfp = GFP_ATOMIC | __GFP_COLD | __GFP_COMP;
-		order = max_t(int, PAGE_ALLOC_COSTLY_ORDER, 1);
-		while (--order >= 0) {
-			pages = alloc_pages(gfp, order);
-			if (pages)
-				break;
-		}
-		if (!pages)
-			return -ENOMEM;
+	struct page *pages = NULL;
+	dma_addr_t pages_dma;
+	int ret;
 
-		/* Map the pages */
-		pages_dma = dma_map_page(pdata->dev, pages, 0,
-					 PAGE_SIZE << order, DMA_FROM_DEVICE);
-		ret = dma_mapping_error(pdata->dev, pages_dma);
-		if (ret) {
-			put_page(pages);
-			return ret;
-		}
+	/* Try to obtain pages, decreasing order if necessary */
+	gfp |= __GFP_COLD | __GFP_COMP;
+	while (order >= 0) {
+		pages = alloc_pages(gfp, order);
+		if (pages)
+			break;
 
-		/* Set the values for this ring */
-		ring->rx_pa.pages = pages;
-		ring->rx_pa.pages_len = PAGE_SIZE << order;
-		ring->rx_pa.pages_offset = 0;
-		ring->rx_pa.pages_dma = pages_dma;
+		order--;
 	}
+	if (!pages)
+		return -ENOMEM;
 
-	get_page(ring->rx_pa.pages);
-	rdata->rx_pa = ring->rx_pa;
+	/* Map the pages */
+	pages_dma = dma_map_page(pdata->dev, pages, 0,
+				 PAGE_SIZE << order, DMA_FROM_DEVICE);
+	ret = dma_mapping_error(pdata->dev, pages_dma);
+	if (ret) {
+		put_page(pages);
+		return ret;
+	}
 
-	rdata->rx_dma = ring->rx_pa.pages_dma + ring->rx_pa.pages_offset;
-	rdata->rx_dma_len = pdata->rx_buf_size;
+	pa->pages = pages;
+	pa->pages_len = PAGE_SIZE << order;
+	pa->pages_offset = 0;
+	pa->pages_dma = pages_dma;
 
-	ring->rx_pa.pages_offset += pdata->rx_buf_size;
-	if ((ring->rx_pa.pages_offset + pdata->rx_buf_size) >
-	    ring->rx_pa.pages_len) {
+	return 0;
+}
+
+static void xgbe_set_buffer_data(struct xgbe_buffer_data *bd,
+				 struct xgbe_page_alloc *pa,
+				 unsigned int len)
+{
+	get_page(pa->pages);
+	bd->pa = *pa;
+
+	bd->dma = pa->pages_dma + pa->pages_offset;
+	bd->dma_len = len;
+
+	pa->pages_offset += len;
+	if ((pa->pages_offset + len) > pa->pages_len) {
 		/* This data descriptor is responsible for unmapping page(s) */
-		rdata->rx_unmap = ring->rx_pa;
+		bd->pa_unmap = *pa;
 
 		/* Get a new allocation next time */
-		ring->rx_pa.pages = NULL;
-		ring->rx_pa.pages_len = 0;
-		ring->rx_pa.pages_offset = 0;
-		ring->rx_pa.pages_dma = 0;
+		pa->pages = NULL;
+		pa->pages_len = 0;
+		pa->pages_offset = 0;
+		pa->pages_dma = 0;
+	}
+}
+
+static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,
+			      struct xgbe_ring *ring,
+			      struct xgbe_ring_data *rdata)
+{
+	int order, ret;
+
+	if (!ring->rx_hdr_pa.pages) {
+		ret = xgbe_alloc_pages(pdata, &ring->rx_hdr_pa, GFP_ATOMIC, 0);
+		if (ret)
+			return ret;
+	}
+
+	if (!ring->rx_buf_pa.pages) {
+		order = max_t(int, PAGE_ALLOC_COSTLY_ORDER - 1, 0);
+		ret = xgbe_alloc_pages(pdata, &ring->rx_buf_pa, GFP_ATOMIC,
+				       order);
+		if (ret)
+			return ret;
 	}
 
+	/* Set up the header page info */
+	xgbe_set_buffer_data(&rdata->rx_hdr, &ring->rx_hdr_pa,
+			     XGBE_SKB_ALLOC_SIZE);
+
+	/* Set up the buffer page info */
+	xgbe_set_buffer_data(&rdata->rx_buf, &ring->rx_buf_pa,
+			     pdata->rx_buf_size);
+
 	return 0;
 }
 
@@ -409,20 +451,28 @@ static void xgbe_unmap_rdata(struct xgbe_prv_data *pdata,
 		rdata->skb = NULL;
 	}
 
-	if (rdata->rx_pa.pages)
-		put_page(rdata->rx_pa.pages);
+	if (rdata->rx_hdr.pa.pages)
+		put_page(rdata->rx_hdr.pa.pages);
 
-	if (rdata->rx_unmap.pages) {
-		dma_unmap_page(pdata->dev, rdata->rx_unmap.pages_dma,
-			       rdata->rx_unmap.pages_len, DMA_FROM_DEVICE);
-		put_page(rdata->rx_unmap.pages);
+	if (rdata->rx_hdr.pa_unmap.pages) {
+		dma_unmap_page(pdata->dev, rdata->rx_hdr.pa_unmap.pages_dma,
+			       rdata->rx_hdr.pa_unmap.pages_len,
+			       DMA_FROM_DEVICE);
+		put_page(rdata->rx_hdr.pa_unmap.pages);
 	}
 
-	memset(&rdata->rx_pa, 0, sizeof(rdata->rx_pa));
-	memset(&rdata->rx_unmap, 0, sizeof(rdata->rx_unmap));
+	if (rdata->rx_buf.pa.pages)
+		put_page(rdata->rx_buf.pa.pages);
+
+	if (rdata->rx_buf.pa_unmap.pages) {
+		dma_unmap_page(pdata->dev, rdata->rx_buf.pa_unmap.pages_dma,
+			       rdata->rx_buf.pa_unmap.pages_len,
+			       DMA_FROM_DEVICE);
+		put_page(rdata->rx_buf.pa_unmap.pages);
+	}
 
-	rdata->rx_dma = 0;
-	rdata->rx_dma_len = 0;
+	memset(&rdata->rx_hdr, 0, sizeof(rdata->rx_hdr));
+	memset(&rdata->rx_buf, 0, sizeof(rdata->rx_buf));
 
 	rdata->tso_header = 0;
 	rdata->len = 0;