lantiq: backport latest upstream patches

This patch includes a series of performance improvements. All patches
were accepted and should land in 5.17.
NAT Performance results on BT Home Hub 5A (kernel 5.10.89, mtu 1500):

	Down		Up
Before	539 Mbps	599 Mbps
After	624 Mbps	695 Mbps

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>

3 files changed, 266 insertions, 0 deletions

diff --git a/target/linux/lantiq/patches-5.10/0713-MIPS-lantiq-dma-increase-descritor-count.patch b/target/linux/lantiq/patches-5.10/0713-MIPS-lantiq-dma-increase-descritor-count.patch
new file mode 100644
index 0000000000..37ed1d4f31
--- /dev/null
+++ b/target/linux/lantiq/patches-5.10/0713-MIPS-lantiq-dma-increase-descritor-count.patch
@@ -0,0 +1,28 @@
+From 5112e9234bbb89f8dd15c983206bd9107b8436d5 Mon Sep 17 00:00:00 2001
+From: Aleksander Jan Bajkowski <olek2@wp.pl>
+Date: Tue, 4 Jan 2022 16:11:42 +0100
+Subject: [PATCH 713/715] MIPS: lantiq: dma: increase descritor count
+
+NAT Performance results on BT Home Hub 5A (kernel 5.10.89, mtu 1500):
+
+	Down		Up
+Before	539 Mbps	599 Mbps
+After	545 Mbps	625 Mbps
+
+Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ arch/mips/include/asm/mach-lantiq/xway/xway_dma.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h
++++ b/arch/mips/include/asm/mach-lantiq/xway/xway_dma.h
+@@ -8,7 +8,7 @@
+ #define LTQ_DMA_H__
+ 
+ #define LTQ_DESC_SIZE		0x08	/* each descriptor is 64bit */
+-#define LTQ_DESC_NUM		0x40	/* 64 descriptors / channel */
++#define LTQ_DESC_NUM		0xC0	/* 192 descriptors / channel */
+ 
+ #define LTQ_DMA_OWN		BIT(31) /* owner bit */
+ #define LTQ_DMA_C		BIT(30) /* complete bit */
diff --git a/target/linux/lantiq/patches-5.10/0714-net-lantiq_xrx200-increase-napi-poll-weigth.patch b/target/linux/lantiq/patches-5.10/0714-net-lantiq_xrx200-increase-napi-poll-weigth.patch
new file mode 100644
index 0000000000..1fa49f406e
--- /dev/null
+++ b/target/linux/lantiq/patches-5.10/0714-net-lantiq_xrx200-increase-napi-poll-weigth.patch
@@ -0,0 +1,32 @@
+From 768818d772d5d4ddc0c7eb2e62848929270ab7a3 Mon Sep 17 00:00:00 2001
+From: Aleksander Jan Bajkowski <olek2@wp.pl>
+Date: Tue, 4 Jan 2022 16:11:43 +0100
+Subject: [PATCH 714/715] net: lantiq_xrx200: increase napi poll weigth
+
+NAT Performance results on BT Home Hub 5A (kernel 5.10.89, mtu 1500):
+
+	Down		Up
+Before	545 Mbps	625 Mbps
+After	577 Mbps	648 Mbps
+
+Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ drivers/net/ethernet/lantiq_xrx200.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/ethernet/lantiq_xrx200.c
++++ b/drivers/net/ethernet/lantiq_xrx200.c
+@@ -606,8 +606,10 @@ static int xrx200_probe(struct platform_
+ 			 PMAC_HD_CTL);
+ 
+ 	/* setup NAPI */
+-	netif_napi_add(net_dev, &priv->chan_rx.napi, xrx200_poll_rx, 32);
+-	netif_tx_napi_add(net_dev, &priv->chan_tx.napi, xrx200_tx_housekeeping, 32);
++	netif_napi_add(net_dev, &priv->chan_rx.napi, xrx200_poll_rx,
++		       NAPI_POLL_WEIGHT);
++	netif_tx_napi_add(net_dev, &priv->chan_tx.napi, xrx200_tx_housekeeping,
++			  NAPI_POLL_WEIGHT);
+ 
+ 	platform_set_drvdata(pdev, priv);
+ 
diff --git a/target/linux/lantiq/patches-5.10/0715-net-lantiq_xrx200-convert-to-build_skb.patch b/target/linux/lantiq/patches-5.10/0715-net-lantiq_xrx200-convert-to-build_skb.patch
new file mode 100644
index 0000000000..b2b014832c
--- /dev/null
+++ b/target/linux/lantiq/patches-5.10/0715-net-lantiq_xrx200-convert-to-build_skb.patch
@@ -0,0 +1,206 @@
+From e015593573b3e3f74bd8a63c05fa92902194a354 Mon Sep 17 00:00:00 2001
+From: Aleksander Jan Bajkowski <olek2@wp.pl>
+Date: Tue, 4 Jan 2022 16:11:44 +0100
+Subject: [PATCH 715/715] net: lantiq_xrx200: convert to build_skb
+
+We can increase the efficiency of rx path by using buffers to receive
+packets then build SKBs around them just before passing into the network
+stack. In contrast, preallocating SKBs too early reduces CPU cache
+efficiency.
+
+NAT Performance results on BT Home Hub 5A (kernel 5.10.89, mtu 1500):
+
+	Down		Up
+Before	577 Mbps	648 Mbps
+After	624 Mbps	695 Mbps
+
+Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+---
+ drivers/net/ethernet/lantiq_xrx200.c | 56 ++++++++++++++++++----------
+ 1 file changed, 36 insertions(+), 20 deletions(-)
+
+--- a/drivers/net/ethernet/lantiq_xrx200.c
++++ b/drivers/net/ethernet/lantiq_xrx200.c
+@@ -63,7 +63,11 @@ struct xrx200_chan {
+ 
+ 	struct napi_struct napi;
+ 	struct ltq_dma_channel dma;
+-	struct sk_buff *skb[LTQ_DESC_NUM];
++
++	union {
++		struct sk_buff *skb[LTQ_DESC_NUM];
++		void *rx_buff[LTQ_DESC_NUM];
++	};
+ 
+ 	struct sk_buff *skb_head;
+ 	struct sk_buff *skb_tail;
+@@ -78,6 +82,7 @@ struct xrx200_priv {
+ 	struct xrx200_chan chan_rx;
+ 
+ 	u16 rx_buf_size;
++	u16 rx_skb_size;
+ 
+ 	struct net_device *net_dev;
+ 	struct device *dev;
+@@ -115,6 +120,12 @@ static int xrx200_buffer_size(int mtu)
+ 	return round_up(xrx200_max_frame_len(mtu), 4 * XRX200_DMA_BURST_LEN);
+ }
+ 
++static int xrx200_skb_size(u16 buf_size)
++{
++	return SKB_DATA_ALIGN(buf_size + NET_SKB_PAD + NET_IP_ALIGN) +
++		SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
++}
++
+ /* drop all the packets from the DMA ring */
+ static void xrx200_flush_dma(struct xrx200_chan *ch)
+ {
+@@ -173,30 +184,29 @@ static int xrx200_close(struct net_devic
+ 	return 0;
+ }
+ 
+-static int xrx200_alloc_skb(struct xrx200_chan *ch)
++static int xrx200_alloc_buf(struct xrx200_chan *ch, void *(*alloc)(unsigned int size))
+ {
+-	struct sk_buff *skb = ch->skb[ch->dma.desc];
++	void *buf = ch->rx_buff[ch->dma.desc];
+ 	struct xrx200_priv *priv = ch->priv;
+ 	dma_addr_t mapping;
+ 	int ret = 0;
+ 
+-	ch->skb[ch->dma.desc] = netdev_alloc_skb_ip_align(priv->net_dev,
+-							  priv->rx_buf_size);
+-	if (!ch->skb[ch->dma.desc]) {
++	ch->rx_buff[ch->dma.desc] = alloc(priv->rx_skb_size);
++	if (!ch->rx_buff[ch->dma.desc]) {
+ 		ret = -ENOMEM;
+ 		goto skip;
+ 	}
+ 
+-	mapping = dma_map_single(priv->dev, ch->skb[ch->dma.desc]->data,
++	mapping = dma_map_single(priv->dev, ch->rx_buff[ch->dma.desc],
+ 				 priv->rx_buf_size, DMA_FROM_DEVICE);
+ 	if (unlikely(dma_mapping_error(priv->dev, mapping))) {
+-		dev_kfree_skb_any(ch->skb[ch->dma.desc]);
+-		ch->skb[ch->dma.desc] = skb;
++		skb_free_frag(ch->rx_buff[ch->dma.desc]);
++		ch->rx_buff[ch->dma.desc] = buf;
+ 		ret = -ENOMEM;
+ 		goto skip;
+ 	}
+ 
+-	ch->dma.desc_base[ch->dma.desc].addr = mapping;
++	ch->dma.desc_base[ch->dma.desc].addr = mapping + NET_SKB_PAD + NET_IP_ALIGN;
+ 	/* Make sure the address is written before we give it to HW */
+ 	wmb();
+ skip:
+@@ -210,13 +220,14 @@ static int xrx200_hw_receive(struct xrx2
+ {
+ 	struct xrx200_priv *priv = ch->priv;
+ 	struct ltq_dma_desc *desc = &ch->dma.desc_base[ch->dma.desc];
+-	struct sk_buff *skb = ch->skb[ch->dma.desc];
++	void *buf = ch->rx_buff[ch->dma.desc];
+ 	u32 ctl = desc->ctl;
+ 	int len = (ctl & LTQ_DMA_SIZE_MASK);
+ 	struct net_device *net_dev = priv->net_dev;
++	struct sk_buff *skb;
+ 	int ret;
+ 
+-	ret = xrx200_alloc_skb(ch);
++	ret = xrx200_alloc_buf(ch, napi_alloc_frag);
+ 
+ 	ch->dma.desc++;
+ 	ch->dma.desc %= LTQ_DESC_NUM;
+@@ -227,19 +238,21 @@ static int xrx200_hw_receive(struct xrx2
+ 		return ret;
+ 	}
+ 
++	skb = build_skb(buf, priv->rx_skb_size);
++	skb_reserve(skb, NET_SKB_PAD);
+ 	skb_put(skb, len);
+ 
+ 	/* add buffers to skb via skb->frag_list */
+ 	if (ctl & LTQ_DMA_SOP) {
+ 		ch->skb_head = skb;
+ 		ch->skb_tail = skb;
++		skb_reserve(skb, NET_IP_ALIGN);
+ 	} else if (ch->skb_head) {
+ 		if (ch->skb_head == ch->skb_tail)
+ 			skb_shinfo(ch->skb_tail)->frag_list = skb;
+ 		else
+ 			ch->skb_tail->next = skb;
+ 		ch->skb_tail = skb;
+-		skb_reserve(ch->skb_tail, -NET_IP_ALIGN);
+ 		ch->skb_head->len += skb->len;
+ 		ch->skb_head->data_len += skb->len;
+ 		ch->skb_head->truesize += skb->truesize;
+@@ -395,12 +408,13 @@ xrx200_change_mtu(struct net_device *net
+ 	struct xrx200_chan *ch_rx = &priv->chan_rx;
+ 	int old_mtu = net_dev->mtu;
+ 	bool running = false;
+-	struct sk_buff *skb;
++	void *buff;
+ 	int curr_desc;
+ 	int ret = 0;
+ 
+ 	net_dev->mtu = new_mtu;
+ 	priv->rx_buf_size = xrx200_buffer_size(new_mtu);
++	priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
+ 
+ 	if (new_mtu <= old_mtu)
+ 		return ret;
+@@ -416,14 +430,15 @@ xrx200_change_mtu(struct net_device *net
+ 
+ 	for (ch_rx->dma.desc = 0; ch_rx->dma.desc < LTQ_DESC_NUM;
+ 	     ch_rx->dma.desc++) {
+-		skb = ch_rx->skb[ch_rx->dma.desc];
+-		ret = xrx200_alloc_skb(ch_rx);
++		buff = ch_rx->rx_buff[ch_rx->dma.desc];
++		ret = xrx200_alloc_buf(ch_rx, netdev_alloc_frag);
+ 		if (ret) {
+ 			net_dev->mtu = old_mtu;
+ 			priv->rx_buf_size = xrx200_buffer_size(old_mtu);
++			priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
+ 			break;
+ 		}
+-		dev_kfree_skb_any(skb);
++		skb_free_frag(buff);
+ 	}
+ 
+ 	ch_rx->dma.desc = curr_desc;
+@@ -476,7 +491,7 @@ static int xrx200_dma_init(struct xrx200
+ 	ltq_dma_alloc_rx(&ch_rx->dma);
+ 	for (ch_rx->dma.desc = 0; ch_rx->dma.desc < LTQ_DESC_NUM;
+ 	     ch_rx->dma.desc++) {
+-		ret = xrx200_alloc_skb(ch_rx);
++		ret = xrx200_alloc_buf(ch_rx, netdev_alloc_frag);
+ 		if (ret)
+ 			goto rx_free;
+ 	}
+@@ -511,7 +526,7 @@ rx_ring_free:
+ 	/* free the allocated RX ring */
+ 	for (i = 0; i < LTQ_DESC_NUM; i++) {
+ 		if (priv->chan_rx.skb[i])
+-			dev_kfree_skb_any(priv->chan_rx.skb[i]);
++			skb_free_frag(priv->chan_rx.rx_buff[i]);
+ 	}
+ 
+ rx_free:
+@@ -528,7 +543,7 @@ static void xrx200_hw_cleanup(struct xrx
+ 
+ 	/* free the allocated RX ring */
+ 	for (i = 0; i < LTQ_DESC_NUM; i++)
+-		dev_kfree_skb_any(priv->chan_rx.skb[i]);
++		skb_free_frag(priv->chan_rx.rx_buff[i]);
+ }
+ 
+ static int xrx200_probe(struct platform_device *pdev)
+@@ -554,6 +569,7 @@ static int xrx200_probe(struct platform_
+ 	net_dev->min_mtu = ETH_ZLEN;
+ 	net_dev->max_mtu = XRX200_DMA_DATA_LEN - xrx200_max_frame_len(0);
+ 	priv->rx_buf_size = xrx200_buffer_size(ETH_DATA_LEN);
++	priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
+ 
+ 	/* load the memory ranges */
+ 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);