net: hns: Fix to adjust buf_size of ring according to mtu

Because buf_size of ring set to 2048, the process of rx_poll_one
can reuse the page, therefore the performance of XGE can improve.
But the chip only supports three bds in one package, so the max mtu
is 6K when it sets to 2048. For better performane in litter mtu, we
need change buf_size according to mtu.

When user change mtu, hns is only change the desc in memory. There
are some desc has been fetched by the chip, these desc can not be
changed by the code. So it needs set the port loopback and send
some packages to let the chip consumes the wrong desc and fetch new
desc.
Because the Pv660 do not support rss indirection, we need add version
check in mtu change process.

Signed-off-by: lipeng <lipeng321@huawei.com>
reviewed-by: Yisen Zhuang <yisen.zhuang@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 238 insertions, 11 deletions

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index 5f67db2dc09c..57b4d59d1097 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -1480,32 +1480,259 @@ static netdev_tx_t hns_nic_net_xmit(struct sk_buff *skb,
 	return (netdev_tx_t)ret;
 }
 
+static void hns_nic_drop_rx_fetch(struct hns_nic_ring_data *ring_data,
+				  struct sk_buff *skb)
+{
+	dev_kfree_skb_any(skb);
+}
+
+#define HNS_LB_TX_RING	0
+static struct sk_buff *hns_assemble_skb(struct net_device *ndev)
+{
+	struct sk_buff *skb;
+	struct ethhdr *ethhdr;
+	int frame_len;
+
+	/* allocate test skb */
+	skb = alloc_skb(64, GFP_KERNEL);
+	if (!skb)
+		return NULL;
+
+	skb_put(skb, 64);
+	skb->dev = ndev;
+	memset(skb->data, 0xFF, skb->len);
+
+	/* must be tcp/ip package */
+	ethhdr = (struct ethhdr *)skb->data;
+	ethhdr->h_proto = htons(ETH_P_IP);
+
+	frame_len = skb->len & (~1ul);
+	memset(&skb->data[frame_len / 2], 0xAA,
+	       frame_len / 2 - 1);
+
+	skb->queue_mapping = HNS_LB_TX_RING;
+
+	return skb;
+}
+
+static int hns_enable_serdes_lb(struct net_device *ndev)
+{
+	struct hns_nic_priv *priv = netdev_priv(ndev);
+	struct hnae_handle *h = priv->ae_handle;
+	struct hnae_ae_ops *ops = h->dev->ops;
+	int speed, duplex;
+	int ret;
+
+	ret = ops->set_loopback(h, MAC_INTERNALLOOP_SERDES, 1);
+	if (ret)
+		return ret;
+
+	ret = ops->start ? ops->start(h) : 0;
+	if (ret)
+		return ret;
+
+	/* link adjust duplex*/
+	if (h->phy_if != PHY_INTERFACE_MODE_XGMII)
+		speed = 1000;
+	else
+		speed = 10000;
+	duplex = 1;
+
+	ops->adjust_link(h, speed, duplex);
+
+	/* wait h/w ready */
+	mdelay(300);
+
+	return 0;
+}
+
+static void hns_disable_serdes_lb(struct net_device *ndev)
+{
+	struct hns_nic_priv *priv = netdev_priv(ndev);
+	struct hnae_handle *h = priv->ae_handle;
+	struct hnae_ae_ops *ops = h->dev->ops;
+
+	ops->stop(h);
+	ops->set_loopback(h, MAC_INTERNALLOOP_SERDES, 0);
+}
+
+/**
+ *hns_nic_clear_all_rx_fetch - clear the chip fetched descriptions. The
+ *function as follows:
+ *    1. if one rx ring has found the page_offset is not equal 0 between head
+ *       and tail, it means that the chip fetched the wrong descs for the ring
+ *       which buffer size is 4096.
+ *    2. we set the chip serdes loopback and set rss indirection to the ring.
+ *    3. construct 64-bytes ip broadcast packages, wait the associated rx ring
+ *       recieving all packages and it will fetch new descriptions.
+ *    4. recover to the original state.
+ *
+ *@ndev: net device
+ */
+static int hns_nic_clear_all_rx_fetch(struct net_device *ndev)
+{
+	struct hns_nic_priv *priv = netdev_priv(ndev);
+	struct hnae_handle *h = priv->ae_handle;
+	struct hnae_ae_ops *ops = h->dev->ops;
+	struct hns_nic_ring_data *rd;
+	struct hnae_ring *ring;
+	struct sk_buff *skb;
+	u32 *org_indir;
+	u32 *cur_indir;
+	int indir_size;
+	int head, tail;
+	int fetch_num;
+	int i, j;
+	bool found;
+	int retry_times;
+	int ret = 0;
+
+	/* alloc indir memory */
+	indir_size = ops->get_rss_indir_size(h) * sizeof(*org_indir);
+	org_indir = kzalloc(indir_size, GFP_KERNEL);
+	if (!org_indir)
+		return -ENOMEM;
+
+	/* store the orginal indirection */
+	ops->get_rss(h, org_indir, NULL, NULL);
+
+	cur_indir = kzalloc(indir_size, GFP_KERNEL);
+	if (!cur_indir) {
+		ret = -ENOMEM;
+		goto cur_indir_alloc_err;
+	}
+
+	/* set loopback */
+	if (hns_enable_serdes_lb(ndev)) {
+		ret = -EINVAL;
+		goto enable_serdes_lb_err;
+	}
+
+	/* foreach every rx ring to clear fetch desc */
+	for (i = 0; i < h->q_num; i++) {
+		ring = &h->qs[i]->rx_ring;
+		head = readl_relaxed(ring->io_base + RCB_REG_HEAD);
+		tail = readl_relaxed(ring->io_base + RCB_REG_TAIL);
+		found = false;
+		fetch_num = ring_dist(ring, head, tail);
+
+		while (head != tail) {
+			if (ring->desc_cb[head].page_offset != 0) {
+				found = true;
+				break;
+			}
+
+			head++;
+			if (head == ring->desc_num)
+				head = 0;
+		}
+
+		if (found) {
+			for (j = 0; j < indir_size / sizeof(*org_indir); j++)
+				cur_indir[j] = i;
+			ops->set_rss(h, cur_indir, NULL, 0);
+
+			for (j = 0; j < fetch_num; j++) {
+				/* alloc one skb and init */
+				skb = hns_assemble_skb(ndev);
+				if (!skb)
+					goto out;
+				rd = &tx_ring_data(priv, skb->queue_mapping);
+				hns_nic_net_xmit_hw(ndev, skb, rd);
+
+				retry_times = 0;
+				while (retry_times++ < 10) {
+					mdelay(10);
+					/* clean rx */
+					rd = &rx_ring_data(priv, i);
+					if (rd->poll_one(rd, fetch_num,
+							 hns_nic_drop_rx_fetch))
+						break;
+				}
+
+				retry_times = 0;
+				while (retry_times++ < 10) {
+					mdelay(10);
+					/* clean tx ring 0 send package */
+					rd = &tx_ring_data(priv,
+							   HNS_LB_TX_RING);
+					if (rd->poll_one(rd, fetch_num, NULL))
+						break;
+				}
+			}
+		}
+	}
+
+out:
+	/* restore everything */
+	ops->set_rss(h, org_indir, NULL, 0);
+	hns_disable_serdes_lb(ndev);
+enable_serdes_lb_err:
+	kfree(cur_indir);
+cur_indir_alloc_err:
+	kfree(org_indir);
+
+	return ret;
+}
+
 static int hns_nic_change_mtu(struct net_device *ndev, int new_mtu)
 {
 	struct hns_nic_priv *priv = netdev_priv(ndev);
 	struct hnae_handle *h = priv->ae_handle;
+	bool if_running = netif_running(ndev);
 	int ret;
 
+	/* MTU < 68 is an error and causes problems on some kernels */
+	if (new_mtu < 68)
+		return -EINVAL;
+
+	/* MTU no change */
+	if (new_mtu == ndev->mtu)
+		return 0;
+
 	if (!h->dev->ops->set_mtu)
 		return -ENOTSUPP;
 
-	if (netif_running(ndev)) {
+	if (if_running) {
 		(void)hns_nic_net_stop(ndev);
 		msleep(100);
+	}
 
-		ret = h->dev->ops->set_mtu(h, new_mtu);
-		if (ret)
-			netdev_err(ndev, "set mtu fail, return value %d\n",
-				   ret);
+	if (priv->enet_ver != AE_VERSION_1 &&
+	    ndev->mtu <= BD_SIZE_2048_MAX_MTU &&
+	    new_mtu > BD_SIZE_2048_MAX_MTU) {
+		/* update desc */
+		hnae_reinit_all_ring_desc(h);
 
-		if (hns_nic_net_open(ndev))
-			netdev_err(ndev, "hns net open fail\n");
-	} else {
-		ret = h->dev->ops->set_mtu(h, new_mtu);
+		/* clear the package which the chip has fetched */
+		ret = hns_nic_clear_all_rx_fetch(ndev);
+
+		/* the page offset must be consist with desc */
+		hnae_reinit_all_ring_page_off(h);
+
+		if (ret) {
+			netdev_err(ndev, "clear the fetched desc fail\n");
+			goto out;
+		}
+	}
+
+	ret = h->dev->ops->set_mtu(h, new_mtu);
+	if (ret) {
+		netdev_err(ndev, "set mtu fail, return value %d\n",
+			   ret);
+		goto out;
 	}
 
-	if (!ret)
-		ndev->mtu = new_mtu;
+	/* finally, set new mtu to netdevice */
+	ndev->mtu = new_mtu;
+
+out:
+	if (if_running) {
+		if (hns_nic_net_open(ndev)) {
+			netdev_err(ndev, "hns net open fail\n");
+			ret = -EINVAL;
+		}
+	}
 
 	return ret;
 }