sfc: move datapath management code

The code that manages the datapath (starting, stopping, including the
port-related bits) will be common.
Three functions have been added that contain bits from other
functions. These will be moved to their final files in later patches.
Small code styling fixes included.
Signed-off-by: Alexandru-Mihai Maftei <amaftei@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/efx_common.c

@@ -101,3 +101,331 @@ void efx_link_status_changed(struct efx_nic *efx)
 	else
 		netif_info(efx, link, efx->net_dev, "link down\n");
 }
+
+/**************************************************************************
+ *
+ * Event queue processing
+ *
+ *************************************************************************/
+
+void efx_start_channels(struct efx_nic *efx)
+{
+	struct efx_tx_queue *tx_queue;
+	struct efx_rx_queue *rx_queue;
+	struct efx_channel *channel;
+
+	efx_for_each_channel(channel, efx) {
+		efx_for_each_channel_tx_queue(tx_queue, channel) {
+			efx_init_tx_queue(tx_queue);
+			atomic_inc(&efx->active_queues);
+		}
+
+		efx_for_each_channel_rx_queue(rx_queue, channel) {
+			efx_init_rx_queue(rx_queue);
+			atomic_inc(&efx->active_queues);
+			efx_stop_eventq(channel);
+			efx_fast_push_rx_descriptors(rx_queue, false);
+			efx_start_eventq(channel);
+		}
+
+		WARN_ON(channel->rx_pkt_n_frags);
+	}
+}
+
+/* Channels are shutdown and reinitialised whilst the NIC is running
+ * to propagate configuration changes (mtu, checksum offload), or
+ * to clear hardware error conditions
+ */
+static void efx_start_datapath(struct efx_nic *efx)
+{
+	netdev_features_t old_features = efx->net_dev->features;
+	bool old_rx_scatter = efx->rx_scatter;
+	size_t rx_buf_len;
+
+	/* Calculate the rx buffer allocation parameters required to
+	 * support the current MTU, including padding for header
+	 * alignment and overruns.
+	 */
+	efx->rx_dma_len = (efx->rx_prefix_size +
+			   EFX_MAX_FRAME_LEN(efx->net_dev->mtu) +
+			   efx->type->rx_buffer_padding);
+	rx_buf_len = (sizeof(struct efx_rx_page_state) + XDP_PACKET_HEADROOM +
+		      efx->rx_ip_align + efx->rx_dma_len);
+	if (rx_buf_len <= PAGE_SIZE) {
+		efx->rx_scatter = efx->type->always_rx_scatter;
+		efx->rx_buffer_order = 0;
+	} else if (efx->type->can_rx_scatter) {
+		BUILD_BUG_ON(EFX_RX_USR_BUF_SIZE % L1_CACHE_BYTES);
+		BUILD_BUG_ON(sizeof(struct efx_rx_page_state) +
+			     2 * ALIGN(NET_IP_ALIGN + EFX_RX_USR_BUF_SIZE,
+				       EFX_RX_BUF_ALIGNMENT) >
+			     PAGE_SIZE);
+		efx->rx_scatter = true;
+		efx->rx_dma_len = EFX_RX_USR_BUF_SIZE;
+		efx->rx_buffer_order = 0;
+	} else {
+		efx->rx_scatter = false;
+		efx->rx_buffer_order = get_order(rx_buf_len);
+	}
+
+	efx_rx_config_page_split(efx);
+	if (efx->rx_buffer_order)
+		netif_dbg(efx, drv, efx->net_dev,
+			  "RX buf len=%u; page order=%u batch=%u\n",
+			  efx->rx_dma_len, efx->rx_buffer_order,
+			  efx->rx_pages_per_batch);
+	else
+		netif_dbg(efx, drv, efx->net_dev,
+			  "RX buf len=%u step=%u bpp=%u; page batch=%u\n",
+			  efx->rx_dma_len, efx->rx_page_buf_step,
+			  efx->rx_bufs_per_page, efx->rx_pages_per_batch);
+
+	/* Restore previously fixed features in hw_features and remove
+	 * features which are fixed now
+	 */
+	efx->net_dev->hw_features |= efx->net_dev->features;
+	efx->net_dev->hw_features &= ~efx->fixed_features;
+	efx->net_dev->features |= efx->fixed_features;
+	if (efx->net_dev->features != old_features)
+		netdev_features_change(efx->net_dev);
+
+	/* RX filters may also have scatter-enabled flags */
+	if (efx->rx_scatter != old_rx_scatter)
+		efx->type->filter_update_rx_scatter(efx);
+
+	/* We must keep at least one descriptor in a TX ring empty.
+	 * We could avoid this when the queue size does not exactly
+	 * match the hardware ring size, but it's not that important.
+	 * Therefore we stop the queue when one more skb might fill
+	 * the ring completely.  We wake it when half way back to
+	 * empty.
+	 */
+	efx->txq_stop_thresh = efx->txq_entries - efx_tx_max_skb_descs(efx);
+	efx->txq_wake_thresh = efx->txq_stop_thresh / 2;
+
+	/* Initialise the channels */
+	efx_start_channels(efx);
+
+	efx_ptp_start_datapath(efx);
+
+	if (netif_device_present(efx->net_dev))
+		netif_tx_wake_all_queues(efx->net_dev);
+}
+
+void efx_stop_channels(struct efx_nic *efx)
+{
+	struct efx_tx_queue *tx_queue;
+	struct efx_rx_queue *rx_queue;
+	struct efx_channel *channel;
+	int rc = 0;
+
+	/* Stop RX refill */
+	efx_for_each_channel(channel, efx) {
+		efx_for_each_channel_rx_queue(rx_queue, channel)
+			rx_queue->refill_enabled = false;
+	}
+
+	efx_for_each_channel(channel, efx) {
+		/* RX packet processing is pipelined, so wait for the
+		 * NAPI handler to complete.  At least event queue 0
+		 * might be kept active by non-data events, so don't
+		 * use napi_synchronize() but actually disable NAPI
+		 * temporarily.
+		 */
+		if (efx_channel_has_rx_queue(channel)) {
+			efx_stop_eventq(channel);
+			efx_start_eventq(channel);
+		}
+	}
+
+	if (efx->type->fini_dmaq)
+		rc = efx->type->fini_dmaq(efx);
+
+	if (rc) {
+		netif_err(efx, drv, efx->net_dev, "failed to flush queues\n");
+	} else {
+		netif_dbg(efx, drv, efx->net_dev,
+			  "successfully flushed all queues\n");
+	}
+
+	efx_for_each_channel(channel, efx) {
+		efx_for_each_channel_rx_queue(rx_queue, channel)
+			efx_fini_rx_queue(rx_queue);
+		efx_for_each_possible_channel_tx_queue(tx_queue, channel)
+			efx_fini_tx_queue(tx_queue);
+	}
+	efx->xdp_rxq_info_failed = false;
+}
+
+static void efx_stop_datapath(struct efx_nic *efx)
+{
+	EFX_ASSERT_RESET_SERIALISED(efx);
+	BUG_ON(efx->port_enabled);
+
+	efx_ptp_stop_datapath(efx);
+
+	efx_stop_channels(efx);
+}
+
+/**************************************************************************
+ *
+ * Port handling
+ *
+ **************************************************************************/
+
+static void efx_start_port(struct efx_nic *efx)
+{
+	netif_dbg(efx, ifup, efx->net_dev, "start port\n");
+	BUG_ON(efx->port_enabled);
+
+	mutex_lock(&efx->mac_lock);
+	efx->port_enabled = true;
+
+	/* Ensure MAC ingress/egress is enabled */
+	efx_mac_reconfigure(efx);
+
+	mutex_unlock(&efx->mac_lock);
+}
+
+/* Cancel work for MAC reconfiguration, periodic hardware monitoring
+ * and the async self-test, wait for them to finish and prevent them
+ * being scheduled again.  This doesn't cover online resets, which
+ * should only be cancelled when removing the device.
+ */
+static void efx_stop_port(struct efx_nic *efx)
+{
+	netif_dbg(efx, ifdown, efx->net_dev, "stop port\n");
+
+	EFX_ASSERT_RESET_SERIALISED(efx);
+
+	mutex_lock(&efx->mac_lock);
+	efx->port_enabled = false;
+	mutex_unlock(&efx->mac_lock);
+
+	/* Serialise against efx_set_multicast_list() */
+	netif_addr_lock_bh(efx->net_dev);
+	netif_addr_unlock_bh(efx->net_dev);
+
+	cancel_delayed_work_sync(&efx->monitor_work);
+	efx_selftest_async_cancel(efx);
+	cancel_work_sync(&efx->mac_work);
+}
+
+/* If the interface is supposed to be running but is not, start
+ * the hardware and software data path, regular activity for the port
+ * (MAC statistics, link polling, etc.) and schedule the port to be
+ * reconfigured.  Interrupts must already be enabled.  This function
+ * is safe to call multiple times, so long as the NIC is not disabled.
+ * Requires the RTNL lock.
+ */
+void efx_start_all(struct efx_nic *efx)
+{
+	EFX_ASSERT_RESET_SERIALISED(efx);
+	BUG_ON(efx->state == STATE_DISABLED);
+
+	/* Check that it is appropriate to restart the interface. All
+	 * of these flags are safe to read under just the rtnl lock
+	 */
+	if (efx->port_enabled || !netif_running(efx->net_dev) ||
+	    efx->reset_pending)
+		return;
+
+	efx_start_port(efx);
+	efx_start_datapath(efx);
+
+	/* Start the hardware monitor if there is one */
+	efx_start_monitor(efx);
+
+	/* Link state detection is normally event-driven; we have
+	 * to poll now because we could have missed a change
+	 */
+	mutex_lock(&efx->mac_lock);
+	if (efx->phy_op->poll(efx))
+		efx_link_status_changed(efx);
+	mutex_unlock(&efx->mac_lock);
+
+	efx->type->start_stats(efx);
+	efx->type->pull_stats(efx);
+	spin_lock_bh(&efx->stats_lock);
+	efx->type->update_stats(efx, NULL, NULL);
+	spin_unlock_bh(&efx->stats_lock);
+}
+
+/* Quiesce the hardware and software data path, and regular activity
+ * for the port without bringing the link down.  Safe to call multiple
+ * times with the NIC in almost any state, but interrupts should be
+ * enabled.  Requires the RTNL lock.
+ */
+void efx_stop_all(struct efx_nic *efx)
+{
+	EFX_ASSERT_RESET_SERIALISED(efx);
+
+	/* port_enabled can be read safely under the rtnl lock */
+	if (!efx->port_enabled)
+		return;
+
+	/* update stats before we go down so we can accurately count
+	 * rx_nodesc_drops
+	 */
+	efx->type->pull_stats(efx);
+	spin_lock_bh(&efx->stats_lock);
+	efx->type->update_stats(efx, NULL, NULL);
+	spin_unlock_bh(&efx->stats_lock);
+	efx->type->stop_stats(efx);
+	efx_stop_port(efx);
+
+	/* Stop the kernel transmit interface.  This is only valid if
+	 * the device is stopped or detached; otherwise the watchdog
+	 * may fire immediately.
+	 */
+	WARN_ON(netif_running(efx->net_dev) &&
+		netif_device_present(efx->net_dev));
+	netif_tx_disable(efx->net_dev);
+
+	efx_stop_datapath(efx);
+}
+
+/* Push loopback/power/transmit disable settings to the PHY, and reconfigure
+ * the MAC appropriately. All other PHY configuration changes are pushed
+ * through phy_op->set_settings(), and pushed asynchronously to the MAC
+ * through efx_monitor().
+ *
+ * Callers must hold the mac_lock
+ */
+int __efx_reconfigure_port(struct efx_nic *efx)
+{
+	enum efx_phy_mode phy_mode;
+	int rc;
+
+	WARN_ON(!mutex_is_locked(&efx->mac_lock));
+
+	/* Disable PHY transmit in mac level loopbacks */
+	phy_mode = efx->phy_mode;
+	if (LOOPBACK_INTERNAL(efx))
+		efx->phy_mode |= PHY_MODE_TX_DISABLED;
+	else
+		efx->phy_mode &= ~PHY_MODE_TX_DISABLED;
+
+	rc = efx->type->reconfigure_port(efx);
+
+	if (rc)
+		efx->phy_mode = phy_mode;
+
+	return rc;
+}
+
+/* Reinitialise the MAC to pick up new PHY settings, even if the port is
+ * disabled.
+ */
+int efx_reconfigure_port(struct efx_nic *efx)
+{
+	int rc;
+
+	EFX_ASSERT_RESET_SERIALISED(efx);
+
+	mutex_lock(&efx->mac_lock);
+	rc = __efx_reconfigure_port(efx);
+	mutex_unlock(&efx->mac_lock);
+
+	return rc;
+}