linux: mvebu: backport mvneta XDP support fixes

This patch backports additional fixes for XDP support in the mvneta driver. These
changes are found upstream as commits:

b37fa92e20ef2 net: mvneta: fix build skb for bm capable devices
f383b2950070c net: mvneta: rely on page_pool_recycle_direct in mvneta_run_xdp
79572c98c554d mvneta driver disallow XDP program on hardware buffer management
44efc78d0e464 net: mvneta: fix XDP support if sw bm is used as fallback

Signed-off-by: Jakov Petrina <jakov.petrina@sartura.hr>

target/linux/mvebu/patches-5.4/020-net-mvneta-fix-build-skb-for-bm-capable-devices.patch

+From b37fa92e20ef28aada852cbf03b368d29a20478c Mon Sep 17 00:00:00 2001
+From: Lorenzo Bianconi <lorenzo@kernel.org>
+Date: Thu, 14 Nov 2019 01:25:55 +0200
+Subject: [PATCH] net: mvneta: fix build skb for bm capable devices
+
+Fix build_skb for bm capable devices when they fall-back using swbm path
+(e.g. when bm properties are configured in device tree but
+CONFIG_MVNETA_BM_ENABLE is not set). In this case rx_offset_correction is
+overwritten so we need to use it building skb instead of
+MVNETA_SKB_HEADROOM directly
+
+Fixes: 8dc9a0888f4c ("net: mvneta: rely on build_skb in mvneta_rx_swbm poll routine")
+Fixes: 0db51da7a8e9 ("net: mvneta: add basic XDP support")
+Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
+Reported-by: Andrew Lunn <andrew@lunn.ch>
+Tested-by: Andrew Lunn <andrew@lunn.ch>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/ethernet/marvell/mvneta.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -2165,7 +2165,7 @@ mvneta_swbm_rx_frame(struct mvneta_port
+ 	prefetch(data);
+ 
+ 	xdp->data_hard_start = data;
+-	xdp->data = data + MVNETA_SKB_HEADROOM + MVNETA_MH_SIZE;
++	xdp->data = data + pp->rx_offset_correction + MVNETA_MH_SIZE;
+ 	xdp->data_end = xdp->data + data_len;
+ 	xdp_set_data_meta_invalid(xdp);
+ 
+@@ -2230,7 +2230,7 @@ mvneta_swbm_add_rx_fragment(struct mvnet
+ 		/* refill descriptor with new buffer later */
+ 		skb_add_rx_frag(rxq->skb,
+ 				skb_shinfo(rxq->skb)->nr_frags,
+-				page, MVNETA_SKB_HEADROOM, data_len,
++				page, pp->rx_offset_correction, data_len,
+ 				PAGE_SIZE);
+ 	}
+ 	page_pool_release_page(rxq->page_pool, page);

target/linux/mvebu/patches-5.4/021-net-mvneta-rely-on-page_pool_recycle_direct-in-mvnet.patch

+From f383b2950070ce4f34e74db94f70bb565b746e97 Mon Sep 17 00:00:00 2001
+From: Lorenzo Bianconi <lorenzo@kernel.org>
+Date: Wed, 20 Nov 2019 16:54:17 +0200
+Subject: [PATCH] net: mvneta: rely on page_pool_recycle_direct in
+ mvneta_run_xdp
+
+Rely on page_pool_recycle_direct and not on xdp_return_buff in
+mvneta_run_xdp. This is a preliminary patch to limit the dma sync len
+to the one strictly necessary
+
+Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
+Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/ethernet/marvell/mvneta.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -2108,7 +2108,8 @@ mvneta_run_xdp(struct mvneta_port *pp, s
+ 		err = xdp_do_redirect(pp->dev, xdp, prog);
+ 		if (err) {
+ 			ret = MVNETA_XDP_DROPPED;
+-			xdp_return_buff(xdp);
++			page_pool_recycle_direct(rxq->page_pool,
++						 virt_to_head_page(xdp->data));
+ 		} else {
+ 			ret = MVNETA_XDP_REDIR;
+ 		}
+@@ -2117,7 +2118,8 @@ mvneta_run_xdp(struct mvneta_port *pp, s
+ 	case XDP_TX:
+ 		ret = mvneta_xdp_xmit_back(pp, xdp);
+ 		if (ret != MVNETA_XDP_TX)
+-			xdp_return_buff(xdp);
++			page_pool_recycle_direct(rxq->page_pool,
++						 virt_to_head_page(xdp->data));
+ 		break;
+ 	default:
+ 		bpf_warn_invalid_xdp_action(act);

target/linux/mvebu/patches-5.4/022-mvneta-driver-disallow-XDP-program-on-hardware-buffe.patch

+From 79572c98c554dcdb080bca547c871a51716dcdf8 Mon Sep 17 00:00:00 2001
+From: Sven Auhagen <sven.auhagen@voleatech.de>
+Date: Sat, 25 Jan 2020 08:07:03 +0000
+Subject: [PATCH] mvneta driver disallow XDP program on hardware buffer
+ management
+
+Recently XDP Support was added to the mvneta driver
+for software buffer management only.
+It is still possible to attach an XDP program if
+hardware buffer management is used.
+It is not doing anything at that point.
+
+The patch disallows attaching XDP programs to mvneta
+if hardware buffer management is used.
+
+I am sorry about that. It is my first submission and I am having
+some troubles with the format of my emails.
+
+v4 -> v5:
+- Remove extra tabs
+
+v3 -> v4:
+- Please ignore v3 I accidentally submitted
+  my other patch with git-send-mail and v4 is correct
+
+v2 -> v3:
+- My mailserver corrupted the patch
+  resubmission with git-send-email
+
+v1 -> v2:
+- Fixing the patches indentation
+
+Signed-off-by: Sven Auhagen <sven.auhagen@voleatech.de>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/ethernet/marvell/mvneta.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -4231,6 +4231,12 @@ static int mvneta_xdp_setup(struct net_d
+ 		return -EOPNOTSUPP;
+ 	}
+ 
++	if (pp->bm_priv) {
++		NL_SET_ERR_MSG_MOD(extack,
++				   "Hardware Buffer Management not supported on XDP");
++		return -EOPNOTSUPP;
++	}
++
+ 	need_update = !!pp->xdp_prog != !!prog;
+ 	if (running && need_update)
+ 		mvneta_stop(dev);

target/linux/mvebu/patches-5.4/023-net-mvneta-fix-XDP-support-if-sw-bm-is-used-as-fallb.patch

+From 44efc78d0e464ce70b45b165c005f8bedc17952e Mon Sep 17 00:00:00 2001
+From: Lorenzo Bianconi <lorenzo@kernel.org>
+Date: Wed, 29 Jan 2020 12:50:53 +0100
+Subject: [PATCH] net: mvneta: fix XDP support if sw bm is used as fallback
+
+In order to fix XDP support if sw buffer management is used as fallback
+for hw bm devices, define MVNETA_SKB_HEADROOM as maximum between
+XDP_PACKET_HEADROOM and NET_SKB_PAD and let the hw aligns the IP header
+to 4-byte boundary.
+Fix rx_offset_correction initialization if mvneta_bm_port_init fails in
+mvneta_resume routine
+
+Fixes: 0db51da7a8e9 ("net: mvneta: add basic XDP support")
+Tested-by: Sven Auhagen <sven.auhagen@voleatech.de>
+Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/ethernet/marvell/mvneta.c | 10 +++++++---
+ 1 file changed, 7 insertions(+), 3 deletions(-)
+
+--- a/drivers/net/ethernet/marvell/mvneta.c
++++ b/drivers/net/ethernet/marvell/mvneta.c
+@@ -324,8 +324,7 @@
+ 	      ETH_HLEN + ETH_FCS_LEN,			     \
+ 	      cache_line_size())
+ 
+-#define MVNETA_SKB_HEADROOM	(max(XDP_PACKET_HEADROOM, NET_SKB_PAD) + \
+-				 NET_IP_ALIGN)
++#define MVNETA_SKB_HEADROOM	max(XDP_PACKET_HEADROOM, NET_SKB_PAD)
+ #define MVNETA_SKB_PAD	(SKB_DATA_ALIGN(sizeof(struct skb_shared_info) + \
+ 			 MVNETA_SKB_HEADROOM))
+ #define MVNETA_SKB_SIZE(len)	(SKB_DATA_ALIGN(len) + MVNETA_SKB_PAD)
+@@ -1172,6 +1171,7 @@ bm_mtu_err:
+ 	mvneta_bm_pool_destroy(pp->bm_priv, pp->pool_short, 1 << pp->id);
+ 
+ 	pp->bm_priv = NULL;
++	pp->rx_offset_correction = MVNETA_SKB_HEADROOM;
+ 	mvreg_write(pp, MVNETA_ACC_MODE, MVNETA_ACC_MODE_EXT1);
+ 	netdev_info(pp->dev, "fail to update MTU, fall back to software BM\n");
+ }
+@@ -4954,7 +4954,6 @@ static int mvneta_probe(struct platform_
+ 	SET_NETDEV_DEV(dev, &pdev->dev);
+ 
+ 	pp->id = global_port_id++;
+-	pp->rx_offset_correction = MVNETA_SKB_HEADROOM;
+ 
+ 	/* Obtain access to BM resources if enabled and already initialized */
+ 	bm_node = of_parse_phandle(dn, "buffer-manager", 0);
+@@ -4979,6 +4978,10 @@ static int mvneta_probe(struct platform_
+ 	}
+ 	of_node_put(bm_node);
+ 
++	/* sw buffer management */
++	if (!pp->bm_priv)
++		pp->rx_offset_correction = MVNETA_SKB_HEADROOM;
++
+ 	err = mvneta_init(&pdev->dev, pp);
+ 	if (err < 0)
+ 		goto err_netdev;
+@@ -5136,6 +5139,7 @@ static int mvneta_resume(struct device *
+ 		err = mvneta_bm_port_init(pdev, pp);
+ 		if (err < 0) {
+ 			dev_info(&pdev->dev, "use SW buffer management\n");
++			pp->rx_offset_correction = MVNETA_SKB_HEADROOM;
+ 			pp->bm_priv = NULL;
+ 		}
+ 	}