130 lines
4.7 KiB
Diff
130 lines
4.7 KiB
Diff
From: Vladimir Oltean <vladimir.oltean@nxp.com>
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Date: Tue, 7 Feb 2023 12:30:27 +0200
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Subject: [PATCH] net: ethernet: mtk_eth_soc: fix DSA TX tag hwaccel for switch
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port 0
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Arınç reports that on his MT7621AT Unielec U7621-06 board and MT7623NI
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Bananapi BPI-R2, packets received by the CPU over mt7530 switch port 0
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(of which this driver acts as the DSA master) are not processed
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correctly by software. More precisely, they arrive without a DSA tag
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(in packet or in the hwaccel area - skb_metadata_dst()), so DSA cannot
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demux them towards the switch's interface for port 0. Traffic from other
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ports receives a skb_metadata_dst() with the correct port and is demuxed
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properly.
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Looking at mtk_poll_rx(), it becomes apparent that this driver uses the
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skb vlan hwaccel area:
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union {
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u32 vlan_all;
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struct {
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__be16 vlan_proto;
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__u16 vlan_tci;
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};
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};
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as a temporary storage for the VLAN hwaccel tag, or the DSA hwaccel tag.
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If this is a DSA master it's a DSA hwaccel tag, and finally clears up
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the skb VLAN hwaccel header.
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I'm guessing that the problem is the (mis)use of API.
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skb_vlan_tag_present() looks like this:
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#define skb_vlan_tag_present(__skb) (!!(__skb)->vlan_all)
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So if both vlan_proto and vlan_tci are zeroes, skb_vlan_tag_present()
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returns precisely false. I don't know for sure what is the format of the
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DSA hwaccel tag, but I surely know that lowermost 3 bits of vlan_proto
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are 0 when receiving from port 0:
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unsigned int port = vlan_proto & GENMASK(2, 0);
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If the RX descriptor has no other bits set to non-zero values in
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RX_DMA_VTAG, then the call to __vlan_hwaccel_put_tag() will not, in
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fact, make the subsequent skb_vlan_tag_present() return true, because
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it's implemented like this:
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static inline void __vlan_hwaccel_put_tag(struct sk_buff *skb,
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__be16 vlan_proto, u16 vlan_tci)
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{
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skb->vlan_proto = vlan_proto;
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skb->vlan_tci = vlan_tci;
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}
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What we need to do to fix this problem (assuming this is the problem) is
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to stop using skb->vlan_all as temporary storage for driver affairs, and
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just create some local variables that serve the same purpose, but
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hopefully better. Instead of calling skb_vlan_tag_present(), let's look
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at a boolean has_hwaccel_tag which we set to true when the RX DMA
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descriptors have something. Disambiguate based on netdev_uses_dsa()
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whether this is a VLAN or DSA hwaccel tag, and only call
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__vlan_hwaccel_put_tag() if we're certain it's a VLAN tag.
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Arınç confirms that the treatment works, so this validates the
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assumption.
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Link: https://lore.kernel.org/netdev/704f3a72-fc9e-714a-db54-272e17612637@arinc9.com/
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Fixes: 2d7605a72906 ("net: ethernet: mtk_eth_soc: enable hardware DSA untagging")
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Reported-by: Arınç ÜNAL <arinc.unal@arinc9.com>
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Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
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Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
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Reviewed-by: Felix Fietkau <nbd@nbd.name>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
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+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
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@@ -1876,7 +1876,9 @@ static int mtk_poll_rx(struct napi_struc
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while (done < budget) {
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unsigned int pktlen, *rxdcsum;
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+ bool has_hwaccel_tag = false;
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struct net_device *netdev;
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+ u16 vlan_proto, vlan_tci;
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dma_addr_t dma_addr;
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u32 hash, reason;
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int mac = 0;
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@@ -2016,27 +2018,29 @@ static int mtk_poll_rx(struct napi_struc
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if (netdev->features & NETIF_F_HW_VLAN_CTAG_RX) {
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if (MTK_HAS_CAPS(eth->soc->caps, MTK_NETSYS_V2)) {
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- if (trxd.rxd3 & RX_DMA_VTAG_V2)
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- __vlan_hwaccel_put_tag(skb,
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- htons(RX_DMA_VPID(trxd.rxd4)),
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- RX_DMA_VID(trxd.rxd4));
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+ if (trxd.rxd3 & RX_DMA_VTAG_V2) {
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+ vlan_proto = RX_DMA_VPID(trxd.rxd4);
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+ vlan_tci = RX_DMA_VID(trxd.rxd4);
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+ has_hwaccel_tag = true;
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+ }
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} else if (trxd.rxd2 & RX_DMA_VTAG) {
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- __vlan_hwaccel_put_tag(skb, htons(RX_DMA_VPID(trxd.rxd3)),
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- RX_DMA_VID(trxd.rxd3));
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+ vlan_proto = RX_DMA_VPID(trxd.rxd3);
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+ vlan_tci = RX_DMA_VID(trxd.rxd3);
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+ has_hwaccel_tag = true;
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}
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}
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/* When using VLAN untagging in combination with DSA, the
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* hardware treats the MTK special tag as a VLAN and untags it.
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*/
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- if (skb_vlan_tag_present(skb) && netdev_uses_dsa(netdev)) {
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- unsigned int port = ntohs(skb->vlan_proto) & GENMASK(2, 0);
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+ if (has_hwaccel_tag && netdev_uses_dsa(netdev)) {
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+ unsigned int port = vlan_proto & GENMASK(2, 0);
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if (port < ARRAY_SIZE(eth->dsa_meta) &&
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eth->dsa_meta[port])
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skb_dst_set_noref(skb, ð->dsa_meta[port]->dst);
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-
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- __vlan_hwaccel_clear_tag(skb);
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+ } else if (has_hwaccel_tag) {
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+ __vlan_hwaccel_put_tag(skb, htons(vlan_proto), vlan_tci);
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}
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skb_record_rx_queue(skb, 0);
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