[PATCH 4/4] net: ethernet: ti: cpsw: add ethtool channels support

[Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>]

These ops allow to control number of channels driver is allowed to
work with. The maximum number of channels is 8 for rx and 8 for tx.
After this patch the following commands are possible:

$ ethtool -l eth0
$ ethtool -L eth0 rx 6 tx 6

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
---
 drivers/net/ethernet/ti/cpsw.c | 188 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 188 insertions(+)

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 595ed56..729b8be 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -740,6 +740,11 @@ static void cpsw_rx_handler(void *token, int len, int status)
 	}
 
 requeue:
+	if (netif_dormant(ndev)) {
+		dev_kfree_skb_any(new_skb);
+		return;
+	}
+
 	ch = priv->rxch[skb_get_queue_mapping(new_skb)];
 	ret = cpdma_chan_submit(ch, new_skb, new_skb->data,
 				skb_tailroom(new_skb), 0);
@@ -2077,6 +2082,187 @@ static void cpsw_ethtool_op_complete(struct net_device *ndev)
 		cpsw_err(priv, drv, "ethtool complete failed %d\n", ret);
 }
 
+static void cpsw_get_channels(struct net_device *dev,
+			      struct ethtool_channels *ch)
+{
+	struct cpsw_priv *priv = netdev_priv(dev);
+
+	ch->max_combined = 0;
+	ch->max_rx = CPSW_MAX_QUEUES;
+	ch->max_tx = CPSW_MAX_QUEUES;
+	ch->max_other = 0;
+	ch->other_count = 0;
+	ch->rx_count = priv->rx_ch_num;
+	ch->tx_count = priv->tx_ch_num;
+	ch->combined_count = 0;
+}
+
+static int cpsw_check_ch_settings(struct cpsw_priv *priv,
+				  struct ethtool_channels *ch)
+{
+	if (ch->combined_count)
+		return -EINVAL;
+
+	/* verify we have at least one channel in each direction */
+	if (!ch->rx_count || !ch->tx_count)
+		return -EINVAL;
+
+	if (ch->rx_count > priv->data.channels ||
+	    ch->tx_count > priv->data.channels)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void cpsw_sync_dual_ch_list(struct net_device *sdev,
+				   struct net_device *ddev)
+{
+	struct cpsw_priv *priv_s, *priv_d;
+	int i;
+
+	priv_s = netdev_priv(sdev);
+	priv_d = netdev_priv(ddev);
+
+	priv_d->rx_ch_num = priv_s->rx_ch_num;
+	priv_d->tx_ch_num = priv_s->tx_ch_num;
+
+	for (i = 0; i < priv_d->tx_ch_num; i++)
+		priv_d->txch[i] = priv_s->txch[i];
+	for (i = 0; i < priv_d->rx_ch_num; i++)
+		priv_d->rxch[i] = priv_s->rxch[i];
+}
+
+static int cpsw_update_channels_res(struct cpsw_priv *priv, int ch_num, int rx)
+{
+	int (*poll)(struct napi_struct *, int);
+	void (*handler)(void *, int, int);
+	struct cpdma_chan **chan;
+	int *ch;
+	int ret;
+
+	if (rx) {
+		ch = &priv->rx_ch_num;
+		chan = priv->rxch;
+		handler = cpsw_rx_handler;
+		poll = cpsw_rx_poll;
+	} else {
+		ch = &priv->tx_ch_num;
+		chan = priv->txch;
+		handler = cpsw_tx_handler;
+		poll = cpsw_tx_poll;
+	}
+
+	while (*ch < ch_num) {
+		chan[*ch] = cpdma_chan_create(priv->dma, *ch, handler, rx);
+
+		if (IS_ERR(chan[*ch]))
+			return PTR_ERR(chan[*ch]);
+
+		if (!chan[*ch])
+			return -EINVAL;
+
+		dev_info(priv->dev, "created new %d %s channel\n", *ch,
+			 (rx ? "rx" : "tx"));
+		(*ch)++;
+	}
+
+	while (*ch > ch_num) {
+		int tch = *ch - 1;
+
+		ret = cpdma_chan_destroy(chan[tch]);
+		if (ret)
+			return ret;
+
+		dev_info(priv->dev, "destroyed %d %s channel\n", tch,
+			 (rx ? "rx" : "tx"));
+		(*ch)--;
+	}
+
+	return 0;
+}
+
+static int cpsw_update_channels(struct net_device *dev,
+				struct ethtool_channels *ch)
+{
+	struct cpsw_priv *priv;
+	int ret;
+
+	priv = netdev_priv(dev);
+
+	ret = cpsw_update_channels_res(priv, ch->rx_count, 1);
+	if (ret)
+		return ret;
+
+	ret = cpsw_update_channels_res(priv, ch->tx_count, 0);
+	if (ret)
+		return ret;
+
+	if (priv->data.dual_emac) {
+		int i;
+		/* mirror channels for another SL */
+		for (i = 0; i < priv->data.slaves; i++) {
+			if (priv->slaves[i].ndev == dev)
+				continue;
+
+			cpsw_sync_dual_ch_list(dev, priv->slaves[i].ndev);
+		}
+	}
+
+	return 0;
+}
+
+static int cpsw_set_channels(struct net_device *ndev,
+			     struct ethtool_channels *chs)
+{
+	struct cpsw_priv *priv = netdev_priv(ndev);
+	int ret;
+
+	ret = cpsw_check_ch_settings(priv, chs);
+	if (ret < 0)
+		return ret;
+
+	if (netif_running(ndev)) {
+		netif_tx_stop_all_queues(ndev);
+		cpsw_intr_disable(priv);
+		netif_dormant_on(ndev);
+		cpdma_ctlr_stop(priv->dma);
+	}
+
+	ret = cpsw_update_channels(ndev, chs);
+	if (ret)
+		goto err;
+
+	if (netif_running(ndev)) {
+		/* inform stach about new count of queues */
+		ret = netif_set_real_num_tx_queues(ndev, priv->tx_ch_num);
+		if (ret) {
+			dev_err(priv->dev, "cannot set real number of tx queues\n");
+			goto err;
+		}
+
+		ret = netif_set_real_num_rx_queues(ndev, priv->rx_ch_num);
+		if (ret) {
+			dev_err(priv->dev, "cannot set real number of rx queues\n");
+			goto err;
+		}
+
+		netif_dormant_off(ndev);
+
+		if (cpsw_fill_rx_channels(ndev))
+			goto err;
+
+		cpdma_ctlr_start(priv->dma);
+		cpsw_intr_enable(priv);
+		netif_tx_start_all_queues(ndev);
+	}
+
+	return 0;
+err:
+	dev_err(priv->dev, "cannot update channels number, closing device\n");
+	dev_close(ndev);
+	return ret;
+}
+
 static const struct ethtool_ops cpsw_ethtool_ops = {
 	.get_drvinfo	= cpsw_get_drvinfo,
 	.get_msglevel	= cpsw_get_msglevel,
@@ -2098,6 +2284,8 @@ static const struct ethtool_ops cpsw_ethtool_ops = {
 	.get_regs	= cpsw_get_regs,
 	.begin		= cpsw_ethtool_op_begin,
 	.complete	= cpsw_ethtool_op_complete,
+	.get_channels	= cpsw_get_channels,
+	.set_channels	= cpsw_set_channels,
 };
 
 static void cpsw_slave_init(struct cpsw_slave *slave, struct cpsw_priv *priv,
-- 
1.9.1