net: ethernet: ti: cpsw: add ethtool channels support

These ops allow to control number of channels driver is allowed to
work with at cpdma level. The maximum number of channels is 8 for
rx and 8 for tx. In dual_emac mode the h/w channels are shared
between two interfaces and changing number on one interface changes
number of channels on another.

How many channels are supported and enabled:
$ ethtool -l ethX

Change number of channels (up to 8)
$ ethtool -L ethX rx 6 tx 6

Per-channel statistic:
$ ethtool -S ethX

Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 1fbb50f256036743250bc5fa9d8d38d0b072ab6a..4273e7f9b4aaf363900cd07e508ac116ad86165d 100644 (file)
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -736,6 +736,11 @@ static void cpsw_rx_handler(void *token, int len, int status)
        }
 
 requeue:
+       if (netif_dormant(ndev)) {
+               dev_kfree_skb_any(new_skb);
+               return;
+       }
+
        ch = cpsw->rxch[skb_get_queue_mapping(new_skb)];
        ret = cpdma_chan_submit(ch, new_skb, new_skb->data,
                                skb_tailroom(new_skb), 0);
@@ -2060,6 +2065,179 @@ 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 *ndev,
+                             struct ethtool_channels *ch)
+{
+       struct cpsw_common *cpsw = ndev_to_cpsw(ndev);
+
+       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 = cpsw->rx_ch_num;
+       ch->tx_count = cpsw->tx_ch_num;
+       ch->combined_count = 0;
+}
+
+static int cpsw_check_ch_settings(struct cpsw_common *cpsw,
+                                 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 > cpsw->data.channels ||
+           ch->tx_count > cpsw->data.channels)
+               return -EINVAL;
+
+       return 0;
+}
+
+static int cpsw_update_channels_res(struct cpsw_priv *priv, int ch_num, int rx)
+{
+       int (*poll)(struct napi_struct *, int);
+       struct cpsw_common *cpsw = priv->cpsw;
+       void (*handler)(void *, int, int);
+       struct cpdma_chan **chan;
+       int ret, *ch;
+
+       if (rx) {
+               ch = &cpsw->rx_ch_num;
+               chan = cpsw->rxch;
+               handler = cpsw_rx_handler;
+               poll = cpsw_rx_poll;
+       } else {
+               ch = &cpsw->tx_ch_num;
+               chan = cpsw->txch;
+               handler = cpsw_tx_handler;
+               poll = cpsw_tx_poll;
+       }
+
+       while (*ch < ch_num) {
+               chan[*ch] = cpdma_chan_create(cpsw->dma, *ch, handler, rx);
+
+               if (IS_ERR(chan[*ch]))
+                       return PTR_ERR(chan[*ch]);
+
+               if (!chan[*ch])
+                       return -EINVAL;
+
+               cpsw_info(priv, ifup, "created new %d %s channel\n", *ch,
+                         (rx ? "rx" : "tx"));
+               (*ch)++;
+       }
+
+       while (*ch > ch_num) {
+               (*ch)--;
+
+               ret = cpdma_chan_destroy(chan[*ch]);
+               if (ret)
+                       return ret;
+
+               cpsw_info(priv, ifup, "destroyed %d %s channel\n", *ch,
+                         (rx ? "rx" : "tx"));
+       }
+
+       return 0;
+}
+
+static int cpsw_update_channels(struct cpsw_priv *priv,
+                               struct ethtool_channels *ch)
+{
+       int ret;
+
+       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;
+
+       return 0;
+}
+
+static int cpsw_set_channels(struct net_device *ndev,
+                            struct ethtool_channels *chs)
+{
+       struct cpsw_priv *priv = netdev_priv(ndev);
+       struct cpsw_common *cpsw = priv->cpsw;
+       struct cpsw_slave *slave;
+       int i, ret;
+
+       ret = cpsw_check_ch_settings(cpsw, chs);
+       if (ret < 0)
+               return ret;
+
+       /* Disable NAPI scheduling */
+       cpsw_intr_disable(cpsw);
+
+       /* Stop all transmit queues for every network device.
+        * Disable re-using rx descriptors with dormant_on.
+        */
+       for (i = cpsw->data.slaves, slave = cpsw->slaves; i; i--, slave++) {
+               if (!(slave->ndev && netif_running(slave->ndev)))
+                       continue;
+
+               netif_tx_stop_all_queues(slave->ndev);
+               netif_dormant_on(slave->ndev);
+       }
+
+       /* Handle rest of tx packets and stop cpdma channels */
+       cpdma_ctlr_stop(cpsw->dma);
+       ret = cpsw_update_channels(priv, chs);
+       if (ret)
+               goto err;
+
+       for (i = cpsw->data.slaves, slave = cpsw->slaves; i; i--, slave++) {
+               if (!(slave->ndev && netif_running(slave->ndev)))
+                       continue;
+
+               /* Inform stack about new count of queues */
+               ret = netif_set_real_num_tx_queues(slave->ndev,
+                                                  cpsw->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(slave->ndev,
+                                                  cpsw->rx_ch_num);
+               if (ret) {
+                       dev_err(priv->dev, "cannot set real number of rx queues\n");
+                       goto err;
+               }
+
+               /* Enable rx packets handling */
+               netif_dormant_off(slave->ndev);
+       }
+
+       if (cpsw_common_res_usage_state(cpsw)) {
+               if (cpsw_fill_rx_channels(priv))
+                       goto err;
+
+               /* After this receive is started */
+               cpdma_ctlr_start(cpsw->dma);
+               cpsw_intr_enable(cpsw);
+       }
+
+       /* Resume transmit for every affected interface */
+       for (i = cpsw->data.slaves, slave = cpsw->slaves; i; i--, slave++) {
+               if (!(slave->ndev && netif_running(slave->ndev)))
+                       continue;
+               netif_tx_start_all_queues(slave->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,
@@ -2081,6 +2259,8 @@ 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_common *cpsw,