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105 lines
3.1 KiB
Diff
105 lines
3.1 KiB
Diff
From c3e6b2c35b34214c58c1e90d65dab5f5393608e7 Mon Sep 17 00:00:00 2001
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From: Aleksander Jan Bajkowski <olek2@wp.pl>
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Date: Mon, 3 Jan 2022 20:43:16 +0100
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Subject: [PATCH] net: lantiq_xrx200: add ingress SG DMA support
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This patch adds support for scatter gather DMA. DMA in PMAC splits
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the packet into several buffers when the MTU on the CPU port is
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less than the MTU of the switch. The first buffer starts at an
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offset of NET_IP_ALIGN. In subsequent buffers, dma ignores the
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offset. Thanks to this patch, the user can still connect to the
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device in such a situation. For normal configurations, the patch
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has no effect on performance.
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Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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drivers/net/ethernet/lantiq_xrx200.c | 47 +++++++++++++++++++++++-----
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1 file changed, 40 insertions(+), 7 deletions(-)
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--- a/drivers/net/ethernet/lantiq_xrx200.c
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+++ b/drivers/net/ethernet/lantiq_xrx200.c
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@@ -26,6 +26,9 @@
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#define XRX200_DMA_RX 0
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#define XRX200_DMA_TX 1
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+#define XRX200_DMA_PACKET_COMPLETE 0
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+#define XRX200_DMA_PACKET_IN_PROGRESS 1
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+
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/* cpu port mac */
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#define PMAC_RX_IPG 0x0024
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#define PMAC_RX_IPG_MASK 0xf
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@@ -61,6 +64,9 @@ struct xrx200_chan {
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struct ltq_dma_channel dma;
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struct sk_buff *skb[LTQ_DESC_NUM];
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+ struct sk_buff *skb_head;
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+ struct sk_buff *skb_tail;
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+
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struct xrx200_priv *priv;
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};
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@@ -204,7 +210,8 @@ static int xrx200_hw_receive(struct xrx2
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struct xrx200_priv *priv = ch->priv;
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struct ltq_dma_desc *desc = &ch->dma.desc_base[ch->dma.desc];
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struct sk_buff *skb = ch->skb[ch->dma.desc];
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- int len = (desc->ctl & LTQ_DMA_SIZE_MASK);
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+ u32 ctl = desc->ctl;
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+ int len = (ctl & LTQ_DMA_SIZE_MASK);
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struct net_device *net_dev = priv->net_dev;
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int ret;
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@@ -220,12 +227,36 @@ static int xrx200_hw_receive(struct xrx2
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}
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skb_put(skb, len);
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- skb->protocol = eth_type_trans(skb, net_dev);
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- netif_receive_skb(skb);
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- net_dev->stats.rx_packets++;
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- net_dev->stats.rx_bytes += len;
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- return 0;
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+ /* add buffers to skb via skb->frag_list */
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+ if (ctl & LTQ_DMA_SOP) {
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+ ch->skb_head = skb;
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+ ch->skb_tail = skb;
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+ } else if (ch->skb_head) {
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+ if (ch->skb_head == ch->skb_tail)
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+ skb_shinfo(ch->skb_tail)->frag_list = skb;
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+ else
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+ ch->skb_tail->next = skb;
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+ ch->skb_tail = skb;
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+ skb_reserve(ch->skb_tail, -NET_IP_ALIGN);
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+ ch->skb_head->len += skb->len;
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+ ch->skb_head->data_len += skb->len;
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+ ch->skb_head->truesize += skb->truesize;
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+ }
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+
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+ if (ctl & LTQ_DMA_EOP) {
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+ ch->skb_head->protocol = eth_type_trans(ch->skb_head, net_dev);
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+ netif_receive_skb(ch->skb_head);
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+ net_dev->stats.rx_packets++;
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+ net_dev->stats.rx_bytes += ch->skb_head->len;
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+ ch->skb_head = NULL;
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+ ch->skb_tail = NULL;
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+ ret = XRX200_DMA_PACKET_COMPLETE;
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+ } else {
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+ ret = XRX200_DMA_PACKET_IN_PROGRESS;
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+ }
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+
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+ return ret;
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}
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static int xrx200_poll_rx(struct napi_struct *napi, int budget)
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@@ -240,7 +271,9 @@ static int xrx200_poll_rx(struct napi_st
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if ((desc->ctl & (LTQ_DMA_OWN | LTQ_DMA_C)) == LTQ_DMA_C) {
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ret = xrx200_hw_receive(ch);
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- if (ret)
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+ if (ret == XRX200_DMA_PACKET_IN_PROGRESS)
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+ continue;
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+ if (ret != XRX200_DMA_PACKET_COMPLETE)
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return ret;
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rx++;
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} else {
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