path: root/drivers/net/ethernet/arc/emac_main.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
 *
 * Driver for the ARC EMAC 10100 (hardware revision 5)
 *
 * Contributors:
 *		Amit Bhor
 *		Sameer Dhavale
 *		Vineet Gupta
 */

#include <linux/crc32.h>
#include <linux/etherdevice.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_mdio.h>
#include <linux/of_net.h>
#include <linux/of_platform.h>

#include "emac.h"

static void arc_emac_restart(struct net_device *ndev);

/**
 * arc_emac_tx_avail - Return the number of available slots in the tx ring.
 * @priv: Pointer to ARC EMAC private data structure.
 *
 * returns: the number of slots available for transmission in tx the ring.
 */
static inline int arc_emac_tx_avail(struct arc_emac_priv *priv)
{
	return (priv->txbd_dirty + TX_BD_NUM - priv->txbd_curr - 1) % TX_BD_NUM;
}

/**
 * arc_emac_adjust_link - Adjust the PHY link duplex.
 * @ndev:	Pointer to the net_device structure.
 *
 * This function is called to change the duplex setting after auto negotiation
 * is done by the PHY.
 */
static void arc_emac_adjust_link(struct net_device *ndev)
{
	struct arc_emac_priv *priv = netdev_priv(ndev);
	struct phy_device *phy_dev = ndev->phydev;
	unsigned int reg, state_changed = 0;

	if (priv->link != phy_dev->link) {
		priv->link = phy_dev->link;
		state_changed = 1;
	}

	if (priv->speed != phy_dev->speed) {
		priv->speed = phy_dev->speed;
		state_changed = 1;
		if (priv->set_mac_speed)
			priv->set_mac_speed(priv, priv->speed);
	}

	if (priv->duplex != phy_dev->duplex) {
		reg = arc_reg_get(priv, R_CTRL);

		if (phy_dev->duplex == DUPLEX_FULL)
			reg |= ENFL_MASK;
		else
			reg &= ~ENFL_MASK;

		arc_reg_set(priv, R_CTRL, reg);
		priv->duplex = phy_dev->duplex;
		state_changed = 1;
	}

	if (state_changed)
		phy_print_status(phy_dev);
}

/**
 * arc_emac_get_drvinfo - Get EMAC driver information.
 * @ndev:	Pointer to net_device structure.
 * @info:	Pointer to ethtool_drvinfo structure.
 *
 * This implements ethtool command for getting the driver information.
 * Issue "ethtool -i ethX" under linux prompt to execute this function.
 */
static void arc_emac_get_drvinfo(struct net_device *ndev,
				 struct ethtool_drvinfo *info)
{
	struct arc_emac_priv *priv = netdev_priv(ndev);

	strlcpy(info->driver, priv->drv_name, sizeof(info->driver));
}

static const struct ethtool_ops arc_emac_ethtool_ops = {
	.get_drvinfo	= arc_emac_get_drvinfo,
	.get_link	= ethtool_op_get_link,
	.get_link_ksettings = phy_ethtool_get_link_ksettings,
	.set_link_ksettings = phy_ethtool_set_link_ksettings,
};

#define FIRST_OR_LAST_MASK	(FIRST_MASK | LAST_MASK)

/**
 * arc_emac_tx_clean - clears processed by EMAC Tx BDs.
 * @ndev:	Pointer to the network device.
 */
static void arc_emac_tx_clean(struct net_device *ndev)
{
	struct arc_emac_priv *priv = netdev_priv(ndev);
	struct net_device_stats *stats = &ndev->stats;
	unsigned int i;

	for (i = 0; i < TX_BD_NUM; i++) {
		unsigned int *txbd_dirty = &priv->txbd_dirty;
		struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
		struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
		struct sk_buff *skb = tx_buff->skb;
		unsigned int info = le32_to_cpu(txbd->info);

		if ((info & FOR_EMAC) || !txbd->data || !skb)
			break;

		if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
			stats->tx_errors++;
			stats->tx_dropped++;

			if (info & DEFR)
				stats->tx_carrier_errors++;

			if (info & LTCL)
				stats->collisions++;

			if (info & UFLO)
				stats->tx_fifo_errors++;
		} else if (likely(info & FIRST_OR_LAST_MASK)) {
			stats->tx_packets++;
			stats->tx_bytes += skb->len;
		}

		dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
				 dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);

		/* return the sk_buff to system */
		dev_consume_skb_irq(skb);

		txbd->data = 0;
		txbd->info = 0;
		tx_buff->skb = NULL;

		*txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
	}

	/* Ensure that txbd_dirty is visible to tx() before checking
	 * for queue stopped.
	 */
	smp_mb();

	if (netif_queue_stopped(ndev) && arc_emac_tx_avail(priv))
		netif_wake_queue(ndev);
}

/**
 * arc_emac_rx - processing of Rx packets.
 * @ndev:	Pointer to the network device.
 * @budget:	How many BDs to process on 1 call.
 *
 * returns:	Number of processed BDs
 *
 * Iterate through Rx BDs and deliver received packages to upper layer.
 */
static int arc_emac_rx(struct net_device *ndev, int budget)
{
	struct arc_emac_priv *priv = netdev_priv(ndev);
	unsigned int work_done;

	for (work_done = 0; work_done < budget; work_done++) {
		unsigned int *last_rx_bd = &priv->last_rx_bd;
		struct net_device_stats *stats = &ndev->stats;
		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd