drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

/*******************************************************************************
  This is the driver for the ST MAC 10/100/1000 on-chip Ethernet controllers.
  ST Ethernet IPs are built around a Synopsys IP Core.

	Copyright(C) 2007-2011 STMicroelectronics Ltd

  This program is free software; you can redistribute it and/or modify it
  under the terms and conditions of the GNU General Public License,
  version 2, as published by the Free Software Foundation.

  This program is distributed in the hope it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  more details.

  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

  The full GNU General Public License is included in this distribution in
  the file called "COPYING".

  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>

  Documentation available at:
	http://www.stlinux.com
  Support available at:
	https://bugzilla.stlinux.com/
*******************************************************************************/

#include <linux/clk.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/skbuff.h>
#include <linux/ethtool.h>
#include <linux/if_ether.h>
#include <linux/crc32.h>
#include <linux/mii.h>
#include <linux/if.h>
#include <linux/if_vlan.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/prefetch.h>
#ifdef CONFIG_STMMAC_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#endif /* CONFIG_STMMAC_DEBUG_FS */
#include <linux/net_tstamp.h>
#include "stmmac_ptp.h"
#include "stmmac.h"

#define STMMAC_ALIGN(x)	L1_CACHE_ALIGN(x)
#define JUMBO_LEN	9000

/* Module parameters */
#define TX_TIMEO	5000
static int watchdog = TX_TIMEO;
module_param(watchdog, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(watchdog, "Transmit timeout in milliseconds (default 5s)");

static int debug = -1;
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Message Level (-1: default, 0: no output, 16: all)");

int phyaddr = -1;
module_param(phyaddr, int, S_IRUGO);
MODULE_PARM_DESC(phyaddr, "Physical device address");

#define DMA_TX_SIZE 256
static int dma_txsize = DMA_TX_SIZE;
module_param(dma_txsize, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dma_txsize, "Number of descriptors in the TX list");

#define DMA_RX_SIZE 256
static int dma_rxsize = DMA_RX_SIZE;
module_param(dma_rxsize, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dma_rxsize, "Number of descriptors in the RX list");

static int flow_ctrl = FLOW_OFF;
module_param(flow_ctrl, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(flow_ctrl, "Flow control ability [on/off]");

static int pause = PAUSE_TIME;
module_param(pause, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(pause, "Flow Control Pause Time");

#define TC_DEFAULT 64
static int tc = TC_DEFAULT;
module_param(tc, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(tc, "DMA threshold control value");

#define DMA_BUFFER_SIZE	BUF_SIZE_2KiB
static int buf_sz = DMA_BUFFER_SIZE;
module_param(buf_sz, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(buf_sz, "DMA buffer size");

static const u32 default_msg_level = (NETIF_MSG_DRV | NETIF_MSG_PROBE |
				      NETIF_MSG_LINK | NETIF_MSG_IFUP |
				      NETIF_MSG_IFDOWN | NETIF_MSG_TIMER);

#define STMMAC_DEFAULT_LPI_TIMER	1000
static int eee_timer = STMMAC_DEFAULT_LPI_TIMER;
module_param(eee_timer, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(eee_timer, "LPI tx expiration time in msec");
#define STMMAC_LPI_TIMER(x) (jiffies + msecs_to_jiffies(x))

/* By default the driver will use the ring mode to manage tx and rx descriptors
 * but passing this value so user can force to use the chain instead of the ring
 */
static unsigned int chain_mode;
module_param(chain_mode, int, S_IRUGO);
MODULE_PARM_DESC(chain_mode, "To use chain instead of ring mode");

static irqreturn_t stmmac_interrupt(int irq, void *dev_id);

#ifdef CONFIG_STMMAC_DEBUG_FS
static int stmmac_init_fs(struct net_device *dev);
static void stmmac_exit_fs(void);
#endif

#define STMMAC_COAL_TIMER(x) (jiffies + usecs_to_jiffies(x))

/**
 * stmmac_verify_args - verify the driver parameters.
 * Description: it verifies if some wrong parameter is passed to the driver.
 * Note that wrong parameters are replaced with the default values.
 */
static void stmmac_verify_args(void)
{
	if (unlikely(watchdog < 0))
		watchdog = TX_TIMEO;
	if (unlikely(dma_rxsize < 0))
		dma_rxsize = DMA_RX_SIZE;
	if (unlikely(dma_txsize < 0))
		dma_txsize = DMA_TX_SIZE;
	if (unlikely((buf_sz < DMA_BUFFER_SIZE) || (buf_sz > BUF_SIZE_16KiB)))
		buf_sz = DMA_BUFFER_SIZE;
	if (unlikely(flow_ctrl > 1))
		flow_ctrl = FLOW_AUTO;
	else if (likely(flow_ctrl < 0))
		flow_ctrl = FLOW_OFF;
	if (unlikely((pause < 0) || (pause > 0xffff)))
		pause = PAUSE_TIME;
	if (eee_timer < 0)
		eee_timer = STMMAC_DEFAULT_LPI_TIMER;
}

/**
 * stmmac_clk_csr_set - dynamically set the MDC clock
 * @priv: driver private structure
 * Description: this is to dynamically set the MDC clock according to the csr
 * clock input.
 * Note:
 *	If a specific clk_csr value is passed from the platform
 *	this means that the CSR Clock Range selection cannot be
 *	changed at run-time and it is fixed (as reported in the driver
 *	documentation). Viceversa the driver will try to set the MDC
 *	clock dynamically according to the actual clock input.
 */
static void stmmac_clk_csr_set(struct stmmac_priv *priv)
{
	u32 clk_rate;

	clk_rate = clk_get_rate(priv->stmmac_clk);

	/* Platform provided default clk_csr would be assumed valid
	 * for all other cases except for the below mentioned ones.
	 * For values higher than the IEEE 802.3 specified frequency
	 * we can not estimate the proper divider as it is not known
	 * the frequency of clk_csr_i. So we do not change the default
	 * divider.
	 */
	if (!(priv->clk_csr & MAC_CSR_H_FRQ_MASK)) {
		if (clk_rate < CSR_F_35M)
			priv->clk_csr = STMMAC_CSR_20_35M;
		else if ((clk_rate >= CSR_F_35M) && (clk_rate < CSR_F_60M))
			priv->clk_csr = STMMAC_CSR_35_60M;
		else if ((clk_rate >= CSR_F_60M) && (clk_rate < CSR_F_100M))
			priv->clk_csr = STMMAC_CSR_60_100M;
		else if ((clk_rate >= CSR_F_100M) && (clk_rate < CSR_F_150M))
			priv->clk_csr = STMMAC_CSR_100_150M;
		else if ((clk_rate >= CSR_F_150M) && (clk_rate < CSR_F_250M))
			priv->clk_csr = STMMAC_CSR_150_250M;
		else if ((clk_rate >= CSR_F_250M) && (clk_rate < CSR_F_300M))
			priv->clk_csr = STMMAC_CSR_250_300M;
	}
}

static void print_pkt(unsigned char *buf, int len)
{
	int j;
	pr_debug("len = %d byte, buf addr: 0x%p", len, buf);
	for (j = 0; j < len; j++) {
		if ((j % 16) == 0)
			pr_debug("\n %03x:", j);
		pr_debug(" %02x", buf[j]);
	}
	pr_debug("\n");
}

/* minimum number of free TX descriptors required to wake up TX process */
#define STMMAC_TX_THRESH(x)	(x->dma_tx_size/4)

static inline u32 stmmac_tx_avail(struct stmmac_priv *priv)
{
	return priv->dirty_tx + priv->dma_tx_size - priv->cur_tx - 1;
}

/**
 * stmmac_hw_fix_mac_speed: callback for speed selection
 * @priv: driver private structure
 * Description: on some platforms (e.g. ST), some HW system configuraton
 * registers have to be set according to the link speed negotiated.
 */
static inline void stmmac_hw_fix_mac_speed(struct stmmac_priv *priv)
{
	struct phy_device *phydev = priv->phydev;

	if (likely(priv->plat->fix_mac_speed))
		priv->plat->fix_mac_speed(priv->plat->bsp_priv, phydev->speed);
}

/**
 * stmmac_enable_eee_mode: Check and enter in LPI mode
 * @priv: driver private structure
 * Description: this function is to verify and enter in LPI mode for EEE.
 */
static void stmmac_enable_eee_mode(struct stmmac_priv *priv)
{
	/* Check and enter in LPI mode */
	if ((priv->dirty_tx == priv->cur_tx) &&
	    (priv->tx_path_in_lpi_mode == false))
		priv->hw->mac->set_eee_mode(priv->ioaddr);
}

/**
 * stmmac_disable_eee_mode: disable/exit from EEE
 * @priv: driver private structure
 * Description: this function is to exit and disable EEE in case of
 * LPI state is true. This is called by the xmit.
 */
void stmmac_disable_eee_mode(struct stmmac_priv *priv)
{
	priv->hw->mac->reset_eee_mode(priv->ioaddr);
	del_timer_sync(&priv->eee_ctrl_timer);
	priv->tx_path_in_lpi_mode = false;
}

/**
 * stmmac_eee_ctrl_timer: EEE TX SW timer.
 * @arg : data hook
 * Description:
 *  if there is no data transfer and if we are not in LPI state,
 *  then MAC Transmitter can be moved to LPI state.
 */
static void stmmac_eee_ctrl_timer(unsigned long arg)
{
	struct stmmac_priv *priv = (struct stmmac_priv *)arg;

	stmmac_enable_eee_mode(priv);
	mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_TIMER(eee_timer));
}

/**
 * stmmac_eee_init: init EEE
 * @priv: driver private structure
 * Description:
 *  If the EEE support has been enabled while configuring the driver,
 *  if the GMAC actually supports the EEE (from the HW cap reg) and the
 *  phy can also manage EEE, so enable the LPI state and start the timer
 *  to verify if the tx path can enter in LPI state.
 */
bool stmmac_eee_init(struct stmmac_priv *priv)
{
	bool ret = false;

	/* MAC core supports the EEE feature. */
	if (priv->dma_cap.eee) {
		/* Check if the PHY supports EEE */
		if (phy_init_eee(priv->phydev, 1))
			goto out;

		priv->eee_active = 1;
		init_timer(&priv->eee_ctrl_timer);
		priv->eee_ctrl_timer.function = stmmac_eee_ctrl_timer;
		priv->eee_ctrl_timer.data = (unsigned long)priv;
		priv->eee_ctrl_timer.expires = STMMAC_LPI_TIMER(eee_timer);
		add_timer(&priv->eee_ctrl_timer);

		priv->hw->mac->set_eee_timer(priv->ioaddr,
					     STMMAC_DEFAULT_LIT_LS_TIMER,
					     priv->tx_lpi_timer);

		pr_info("stmmac: Energy-Efficient Ethernet initialized\n");

		ret = true;
	}
out:
	return ret;
}

/**
 * stmmac_eee_adjust: adjust HW EEE according to the speed
 * @priv: driver private structure
 * Description:
 *	When the EEE has been already initialised we have to
 *	modify the PLS bit in the LPI ctrl & status reg according
 *	to the PHY link status. For this reason.
 */
static void stmmac_eee_adjust(struct stmmac_priv *priv)
{
	if (priv->eee_enabled)
		priv->hw->mac->set_eee_pls(priv->ioaddr, priv->phydev->link);
}

/* stmmac_get_tx_hwtstamp: get HW TX timestamps
 * @priv: driver private structure
 * @entry : descriptor index to be used.
 * @skb : the socket buffer
 * Description :
 * This function will read timestamp from the descriptor & pass it to stack.
 * and also perform some sanity checks.
 */
static void stmmac_get_tx_hwtstamp(struct stmmac_priv *priv,
				   unsigned int entry, struct sk_buff *skb)
{
	struct skb_shared_hwtstamps shhwtstamp;
	u64 ns;
	void *desc = NULL;

	if (!priv->hwts_tx_en)
		return;

	/* exit if skb doesn't support hw tstamp */
	if (likely(!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)))
		return;

	if (priv->adv_ts)
		desc = (priv->dma_etx + entry);
	else
		desc = (priv->dma_tx + entry);

	/* check tx tstamp status */
	if (!priv->hw->desc->get_tx_timestamp_status((struct dma_desc *)desc))
		return;

	/* get the valid tstamp */
	ns = priv->hw->desc->get_timestamp(desc, priv->adv_ts);

	memset(&shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
	shhwtstamp.hwtstamp = ns_to_ktime(ns);
	/* pass tstamp to stack */
	skb_tstamp_tx(skb, &shhwtstamp);

	return;
}

/* stmmac_get_rx_hwtstamp: get HW RX timestamps
 * @priv: driver private structure
 * @entry : descriptor index to be used.
 * @skb : the socket buffer
 * Description :
 * This function will read received packet's timestamp from the descriptor
 * and pass it to stack. It also perform some sanity checks.
 */
static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv,
				   unsigned int entry, struct sk_buff *skb)
{
	struct skb_shared_hwtstamps *shhwtstamp = NULL;
	u64 ns;
	void *desc = NULL;

	if (!priv->hwts_rx_en)
		return;

	if (priv->adv_ts)
		desc = (priv->dma_erx + entry);
	else
		desc = (priv->dma_rx + entry);

	/* exit if rx tstamp is not valid */
	if (!priv->hw->desc->get_rx_timestamp_status(desc, priv->adv_ts))
		return;

	/* get valid tstamp */
	ns = priv->hw->desc->get_timestamp(desc, priv->adv_ts);
	shhwtstamp = skb_hwtstamps(skb);
	memset(shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
	shhwtstamp->hwtstamp = ns_to_ktime(ns);
}

/**
 *  stmmac_hwtstamp_ioctl - control hardware timestamping.
 *  @dev: device pointer.
 *  @ifr: An IOCTL specefic structure, that can contain a pointer to
 *  a proprietary structure used to pass information to the driver.
 *  Description:
 *  This function configures the MAC to enable/disable both outgoing(TX)
 *  and incoming(RX) packets time stamping based on user input.
 *  Return Value:
 *  0 on success and an appropriate -ve integer on failure.
 */
static int stmmac_hwtstamp_ioctl(struct net_device *dev, struct ifreq *ifr)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	struct hwtstamp_config config;
	struct timespec now;
	u64 temp = 0;
	u32 ptp_v2 = 0;
	u32 tstamp_all = 0;
	u32 ptp_over_ipv4_udp = 0;
	u32 ptp_over_ipv6_udp = 0;
	u32 ptp_over_ethernet = 0;
	u32 snap_type_sel = 0;
	u32 ts_master_en = 0;
	u32 ts_event_en = 0;
	u32 value = 0;

	if (!(priv->dma_cap.time_stamp || priv->adv_ts)) {
		netdev_alert(priv->dev, "No support for HW time stamping\n");
		priv->hwts_tx_en = 0;
		priv->hwts_rx_en = 0;

		return -EOPNOTSUPP;
	}

	if (copy_from_user(&config, ifr->ifr_data,
			   sizeof(struct hwtstamp_config)))
		return -EFAULT;

	pr_debug("%s config flags:0x%x, tx_type:0x%x, rx_filter:0x%x\n",
		 __func__, config.flags, config.tx_type, config.rx_filter);

	/* reserved for future extensions */
	if (config.flags)
		return -EINVAL;

	switch (config.tx_type) {
	case HWTSTAMP_TX_OFF:
		priv->hwts_tx_en = 0;
		break;
	case HWTSTAMP_TX_ON:
		priv->hwts_tx_en = 1;
		break;
	default:
		return -ERANGE;
	}

	if (priv->adv_ts) {
		switch (config.rx_filter) {
		case HWTSTAMP_FILTER_NONE:
			/* time stamp no incoming packet at all */
			config.rx_filter = HWTSTAMP_FILTER_NONE;
			break;

		case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
			/* PTP v1, UDP, any kind of event packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V1_L4_EVENT;
			/* take time stamp for all event messages */
			snap_type_sel = PTP_TCR_SNAPTYPSEL_1;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			break;

		case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
			/* PTP v1, UDP, Sync packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V1_L4_SYNC;
			/* take time stamp for SYNC messages only */
			ts_event_en = PTP_TCR_TSEVNTENA;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			break;

		case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
			/* PTP v1, UDP, Delay_req packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ;
			/* take time stamp for Delay_Req messages only */
			ts_master_en = PTP_TCR_TSMSTRENA;
			ts_event_en = PTP_TCR_TSEVNTENA;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			break;

		case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
			/* PTP v2, UDP, any kind of event packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L4_EVENT;
			ptp_v2 = PTP_TCR_TSVER2ENA;
			/* take time stamp for all event messages */
			snap_type_sel = PTP_TCR_SNAPTYPSEL_1;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			break;

		case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
			/* PTP v2, UDP, Sync packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L4_SYNC;
			ptp_v2 = PTP_TCR_TSVER2ENA;
			/* take time stamp for SYNC messages only */
			ts_event_en = PTP_TCR_TSEVNTENA;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			break;

		case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
			/* PTP v2, UDP, Delay_req packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ;
			ptp_v2 = PTP_TCR_TSVER2ENA;
			/* take time stamp for Delay_Req messages only */
			ts_master_en = PTP_TCR_TSMSTRENA;
			ts_event_en = PTP_TCR_TSEVNTENA;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			break;

		case HWTSTAMP_FILTER_PTP_V2_EVENT:
			/* PTP v2/802.AS1 any layer, any kind of event packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
			ptp_v2 = PTP_TCR_TSVER2ENA;
			/* take time stamp for all event messages */
			snap_type_sel = PTP_TCR_SNAPTYPSEL_1;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			ptp_over_ethernet = PTP_TCR_TSIPENA;
			break;

		case HWTSTAMP_FILTER_PTP_V2_SYNC:
			/* PTP v2/802.AS1, any layer, Sync packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V2_SYNC;
			ptp_v2 = PTP_TCR_TSVER2ENA;
			/* take time stamp for SYNC messages only */
			ts_event_en = PTP_TCR_TSEVNTENA;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			ptp_over_ethernet = PTP_TCR_TSIPENA;
			break;

		case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
			/* PTP v2/802.AS1, any layer, Delay_req packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V2_DELAY_REQ;
			ptp_v2 = PTP_TCR_TSVER2ENA;
			/* take time stamp for Delay_Req messages only */
			ts_master_en = PTP_TCR_TSMSTRENA;
			ts_event_en = PTP_TCR_TSEVNTENA;

			ptp_over_ipv4_udp = PTP_TCR_TSIPV4ENA;
			ptp_over_ipv6_udp = PTP_TCR_TSIPV6ENA;
			ptp_over_ethernet = PTP_TCR_TSIPENA;
			break;

		case HWTSTAMP_FILTER_ALL:
			/* time stamp any incoming packet */
			config.rx_filter = HWTSTAMP_FILTER_ALL;
			tstamp_all = PTP_TCR_TSENALL;
			break;

		default:
			return -ERANGE;
		}
	} else {
		switch (config.rx_filter) {
		case HWTSTAMP_FILTER_NONE:
			config.rx_filter = HWTSTAMP_FILTER_NONE;
			break;
		default:
			/* PTP v1, UDP, any kind of event packet */
			config.rx_filter = HWTSTAMP_FILTER_PTP_V1_L4_EVENT;
			break;
		}
	}
	priv->hwts_rx_en = ((config.rx_filter == HWTSTAMP_FILTER_NONE) ? 0 : 1);

	if (!priv->hwts_tx_en && !priv->hwts_rx_en)
		priv->hw->ptp->config_hw_tstamping(priv->ioaddr, 0);
	else {
		value = (PTP_TCR_TSENA | PTP_TCR_TSCFUPDT | PTP_TCR_TSCTRLSSR |
			 tstamp_all | ptp_v2 | ptp_over_ethernet |
			 ptp_over_ipv6_udp | ptp_over_ipv4_udp | ts_event_en |
			 ts_master_en | snap_type_sel);

		priv->hw->ptp->config_hw_tstamping(priv->ioaddr, value);

		/* program Sub Second Increment reg */
		priv->hw->ptp->config_sub_second_increment(priv->ioaddr);

		/* calculate default added value:
		 * formula is :
		 * addend = (2^32)/freq_div_ratio;
		 * where, freq_div_ratio = STMMAC_SYSCLOCK/50MHz
		 * hence, addend = ((2^32) * 50MHz)/STMMAC_SYSCLOCK;
		 * NOTE: STMMAC_SYSCLOCK should be >= 50MHz to
		 *       achive 20ns accuracy.
		 *
		 * 2^x * y == (y << x), hence
		 * 2^32 * 50000000 ==> (50000000 << 32)
		 */
		temp = (u64) (50000000ULL << 32);
		priv->default_addend = div_u64(temp, STMMAC_SYSCLOCK);
		priv->hw->ptp->config_addend(priv->ioaddr,
					     priv->default_addend);

		/* initialize system time */
		getnstimeofday(&now);
		priv->hw->ptp->init_systime(priv->ioaddr, now.tv_sec,
					    now.tv_nsec);
	}

	return copy_to_user(ifr->ifr_data, &config,
			    sizeof(struct hwtstamp_config)) ? -EFAULT : 0;
}

/**
 * stmmac_init_ptp: init PTP
 * @priv: driver private structure
 * Description: this is to verify if the HW supports the PTPv1 or v2.
 * This is done by looking at the HW cap. register.
 * Also it registers the ptp driver.
 */
static int stmmac_init_ptp(struct stmmac_priv *priv)
{
	if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp))
		return -EOPNOTSUPP;

	if (netif_msg_hw(priv)) {
		if (priv->dma_cap.time_stamp) {
			pr_debug("IEEE 1588-2002 Time Stamp supported\n");
			priv->adv_ts = 0;
		}
		if (priv->dma_cap.atime_stamp && priv->extend_desc) {
			pr_debug
			    ("IEEE 1588-2008 Advanced Time Stamp supported\n");
			priv->adv_ts = 1;
		}
	}

	priv->hw->ptp = &stmmac_ptp;
	priv->hwts_tx_en = 0;
	priv->hwts_rx_en = 0;

	return stmmac_ptp_register(priv);
}

static void stmmac_release_ptp(struct stmmac_priv *priv)
{
	stmmac_ptp_unregister(priv);
}

/**
 * stmmac_adjust_link
 * @dev: net device structure
 * Description: it adjusts the link parameters.
 */
static void stmmac_adjust_link(struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	struct phy_device *phydev = priv->phydev;
	unsigned long flags;
	int new_state = 0;
	unsigned int fc = priv->flow_ctrl, pause_time = priv->pause;

	if (phydev == NULL)
		return;

	spin_lock_irqsave(&priv->lock, flags);

	if (phydev->link) {
		u32 ctrl = readl(priv->ioaddr + MAC_CTRL_REG);

		/* Now we make sure that we can be in full duplex mode.
		 * If not, we operate in half-duplex mode. */
		if (phydev->duplex != priv->oldduplex) {
			new_state = 1;
			if (!(phydev->duplex))
				ctrl &= ~priv->hw->link.duplex;
			else
				ctrl |= priv->hw->link.duplex;
			priv->oldduplex = phydev->duplex;
		}
		/* Flow Control operation */
		if (phydev->pause)
			priv->hw->mac->flow_ctrl(priv->ioaddr, phydev->duplex,
						 fc, pause_time);

		if (phydev->speed != priv->speed) {
			new_state = 1;
			switch (phydev->speed) {
			case 1000:
				if (likely(priv->plat->has_gmac))
					ctrl &= ~priv->hw->link.port;
				stmmac_hw_fix_mac_speed(priv);
				break;
			case 100:
			case 10:
				if (priv->plat->has_gmac) {
					ctrl |= priv->hw->link.port;
					if (phydev->speed == SPEED_100) {
						ctrl |= priv->hw->link.speed;
					} else {
						ctrl &= ~(priv->hw->link.speed);
					}
				} else {
					ctrl &= ~priv->hw->link.port;
				}
				stmmac_hw_fix_mac_speed(priv);
				break;
			default:
				if (netif_msg_link(priv))
					pr_warn("%s: Speed (%d) not 10/100\n",
						dev->name, phydev->speed);
				break;
			}

			priv->speed = phydev->speed;
		}

		writel(ctrl, priv->ioaddr + MAC_CTRL_REG);

		if (!priv->oldlink) {
			new_state = 1;
			priv->oldlink = 1;
		}
	} else if (priv->oldlink) {
		new_state = 1;
		priv->oldlink = 0;
		priv->speed = 0;
		priv->oldduplex = -1;
	}

	if (new_state && netif_msg_link(priv))
		phy_print_status(phydev);

	stmmac_eee_adjust(priv);

	spin_unlock_irqrestore(&priv->lock, flags);
}

/**
 * stmmac_check_pcs_mode: verify if RGMII/SGMII is supported
 * @priv: driver private structure
 * Description: this is to verify if the HW supports the PCS.
 * Physical Coding Sublayer (PCS) interface that can be used when the MAC is
 * configured for the TBI, RTBI, or SGMII PHY interface.
 */
static void stmmac_check_pcs_mode(struct stmmac_priv *priv)
{
	int interface = priv->plat->interface;

	if (priv->dma_cap.pcs) {
		if ((interface == PHY_INTERFACE_MODE_RGMII) ||
		    (interface == PHY_INTERFACE_MODE_RGMII_ID) ||
		    (interface == PHY_INTERFACE_MODE_RGMII_RXID) ||
		    (interface == PHY_INTERFACE_MODE_RGMII_TXID)) {
			pr_debug("STMMAC: PCS RGMII support enable\n");
			priv->pcs = STMMAC_PCS_RGMII;
		} else if (interface == PHY_INTERFACE_MODE_SGMII) {
			pr_debug("STMMAC: PCS SGMII support enable\n");
			priv->pcs = STMMAC_PCS_SGMII;
		}
	}
}

/**
 * stmmac_init_phy - PHY initialization
 * @dev: net device structure
 * Description: it initializes the driver's PHY state, and attaches the PHY
 * to the mac driver.
 *  Return value:
 *  0 on success
 */
static int stmmac_init_phy(struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	struct phy_device *phydev;
	char phy_id_fmt[MII_BUS_ID_SIZE + 3];
	char bus_id[MII_BUS_ID_SIZE];
	int interface = priv->plat->interface;
	priv->oldlink = 0;
	priv->speed = 0;
	priv->oldduplex = -1;

	if (priv->plat->phy_bus_name)
		snprintf(bus_id, MII_BUS_ID_SIZE, "%s-%x",
			 priv->plat->phy_bus_name, priv->plat->bus_id);
	else
		snprintf(bus_id, MII_BUS_ID_SIZE, "stmmac-%x",
			 priv->plat->bus_id);

	snprintf(phy_id_fmt, MII_BUS_ID_SIZE + 3, PHY_ID_FMT, bus_id,
		 priv->plat->phy_addr);
	pr_debug("stmmac_init_phy:  trying to attach to %s\n", phy_id_fmt);

	phydev = phy_connect(dev, phy_id_fmt, &stmmac_adjust_link, interface);

	if (IS_ERR(phydev)) {
		pr_err("%s: Could not attach to PHY\n", dev->name);
		return PTR_ERR(phydev);
	}

	/* Stop Advertising 1000BASE Capability if interface is not GMII */
	if ((interface == PHY_INTERFACE_MODE_MII) ||
	    (interface == PHY_INTERFACE_MODE_RMII))
		phydev->advertising &= ~(SUPPORTED_1000baseT_Half |
					 SUPPORTED_1000baseT_Full);

	/*
	 * Broken HW is sometimes missing the pull-up resistor on the
	 * MDIO line, which results in reads to non-existent devices returning
	 * 0 rather than 0xffff. Catch this here and treat 0 as a non-existent
	 * device as well.
	 * Note: phydev->phy_id is the result of reading the UID PHY registers.
	 */
	if (phydev->phy_id == 0) {
		phy_disconnect(phydev);
		return -ENODEV;
	}
	pr_debug("stmmac_init_phy:  %s: attached to PHY (UID 0x%x)"
		 " Link = %d\n", dev->name, phydev->phy_id, phydev->link);

	priv->phydev = phydev;

	return 0;
}

/**
 * stmmac_display_ring: display ring
 * @head: pointer to the head of the ring passed.
 * @size: size of the ring.
 * @extend_desc: to verify if extended descriptors are used.
 * Description: display the control/status and buffer descriptors.
 */
static void stmmac_display_ring(void *head, int size, int extend_desc)
{
	int i;
	struct dma_extended_desc *ep = (struct dma_extended_desc *)head;
	struct dma_desc *p = (struct dma_desc *)head;

	for (i = 0; i < size; i++) {
		u64 x;
		if (extend_desc) {
			x = *(u64 *) ep;
			pr_info("%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
				i, (unsigned int)virt_to_phys(ep),
				(unsigned int)x, (unsigned int)(x >> 32),
				ep->basic.des2, ep->basic.des3);
			ep++;
		} else {
			x = *(u64 *) p;
			pr_info("%d [0x%x]: 0x%x 0x%x 0x%x 0x%x",
				i, (unsigned int)virt_to_phys(p),
				(unsigned int)x, (unsigned int)(x >> 32),
				p->des2, p->des3);
			p++;
		}
		pr_info("\n");
	}
}

static void stmmac_display_rings(struct stmmac_priv *priv)
{
	unsigned int txsize = priv->dma_tx_size;
	unsigned int rxsize = priv->dma_rx_size;

	if (priv->extend_desc) {
		pr_info("Extended RX descriptor ring:\n");
		stmmac_display_ring((void *)priv->dma_erx, rxsize, 1);
		pr_info("Extended TX descriptor ring:\n");
		stmmac_display_ring((void *)priv->dma_etx, txsize, 1);
	} else {
		pr_info("RX descriptor ring:\n");
		stmmac_display_ring((void *)priv->dma_rx, rxsize, 0);
		pr_info("TX descriptor ring:\n");
		stmmac_display_ring((void *)priv->dma_tx, txsize, 0);
	}
}

static int stmmac_set_bfsize(int mtu, int bufsize)
{
	int ret = bufsize;

	if (mtu >= BUF_SIZE_4KiB)
		ret = BUF_SIZE_8KiB;
	else if (mtu >= BUF_SIZE_2KiB)
		ret = BUF_SIZE_4KiB;
	else if (mtu >= DMA_BUFFER_SIZE)
		ret = BUF_SIZE_2KiB;
	else
		ret = DMA_BUFFER_SIZE;

	return ret;
}

/**
 * stmmac_clear_descriptors: clear descriptors
 * @priv: driver private structure
 * Description: this function is called to clear the tx and rx descriptors
 * in case of both basic and extended descriptors are used.
 */
static void stmmac_clear_descriptors(struct stmmac_priv *priv)
{
	int i;
	unsigned int txsize = priv->dma_tx_size;
	unsigned int rxsize = priv->dma_rx_size;

	/* Clear the Rx/Tx descriptors */
	for (i = 0; i < rxsize; i++)
		if (priv->extend_desc)
			priv->hw->desc->init_rx_desc(&priv->dma_erx[i].basic,
						     priv->use_riwt, priv->mode,
						     (i == rxsize - 1));
		else
			priv->hw->desc->init_rx_desc(&priv->dma_rx[i],
						     priv->use_riwt, priv->mode,
						     (i == rxsize - 1));
	for (i = 0; i < txsize; i++)
		if (priv->extend_desc)
			priv->hw->desc->init_tx_desc(&priv->dma_etx[i].basic,
						     priv->mode,
						     (i == txsize - 1));
		else
			priv->hw->desc->init_tx_desc(&priv->dma_tx[i],
						     priv->mode,
						     (i == txsize - 1));
}

static int stmmac_init_rx_buffers(struct stmmac_priv *priv, struct dma_desc *p,
				  int i)
{
	struct sk_buff *skb;

	skb = __netdev_alloc_skb(priv->dev, priv->dma_buf_sz + NET_IP_ALIGN,
				 GFP_KERNEL);
	if (unlikely(skb == NULL)) {
		pr_err("%s: Rx init fails; skb is NULL\n", __func__);
		return 1;
	}
	skb_reserve(skb, NET_IP_ALIGN);
	priv->rx_skbuff[i] = skb;
	priv->rx_skbuff_dma[i] = dma_map_single(priv->device, skb->data,
						priv->dma_buf_sz,
						DMA_FROM_DEVICE);

	p->des2 = priv->rx_skbuff_dma[i];

	if ((priv->mode == STMMAC_RING_MODE) &&
	    (priv->dma_buf_sz == BUF_SIZE_16KiB))
		priv->hw->ring->init_desc3(p);

	return 0;
}

/**
 * init_dma_desc_rings - init the RX/TX descriptor rings
 * @dev: net device structure
 * Description:  this function initializes the DMA RX/TX descriptors
 * and allocates the socket buffers. It suppors the chained and ring
 * modes.
 */
static void init_dma_desc_rings(struct net_device *dev)
{
	int i;
	struct stmmac_priv *priv = netdev_priv(dev);
	unsigned int txsize = priv->dma_tx_size;
	unsigned int rxsize = priv->dma_rx_size;
	unsigned int bfsize = 0;

	/* Set the max buffer size according to the DESC mode
	 * and the MTU. Note that RING mode allows 16KiB bsize.
	 */
	if (priv->mode == STMMAC_RING_MODE)
		bfsize = priv->hw->ring->set_16kib_bfsize(dev->mtu);

	if (bfsize < BUF_SIZE_16KiB)
		bfsize = stmmac_set_bfsize(dev->mtu, priv->dma_buf_sz);

	if (netif_msg_probe(priv))
		pr_debug("%s: txsize %d, rxsize %d, bfsize %d\n", __func__,
			 txsize, rxsize, bfsize);

	if (priv->extend_desc) {
		priv->dma_erx = dma_alloc_coherent(priv->device, rxsize *
						   sizeof(struct
							  dma_extended_desc),
						   &priv->dma_rx_phy,
						   GFP_KERNEL);
		priv->dma_etx = dma_alloc_coherent(priv->device, txsize *
						   sizeof(struct
							  dma_extended_desc),
						   &priv->dma_tx_phy,
						   GFP_KERNEL);
		if ((!priv->dma_erx) || (!priv->dma_etx))
			return;
	} else {
		priv->dma_rx = dma_alloc_coherent(priv->device, rxsize *
						  sizeof(struct dma_desc),
						  &priv->dma_rx_phy,
						  GFP_KERNEL);
		priv->dma_tx = dma_alloc_coherent(priv->device, txsize *
						  sizeof(struct dma_desc),
						  &priv->dma_tx_phy,
						  GFP_KERNEL);
		if ((!priv->dma_rx) || (!priv->dma_tx))
			return;
	}

	priv->rx_skbuff_dma = kmalloc_array(rxsize, sizeof(dma_addr_t),
					    GFP_KERNEL);
	priv->rx_skbuff = kmalloc_array(rxsize, sizeof(struct sk_buff *),
					GFP_KERNEL);
	priv->tx_skbuff_dma = kmalloc_array(txsize, sizeof(dma_addr_t),
					    GFP_KERNEL);
	priv->tx_skbuff = kmalloc_array(txsize, sizeof(struct sk_buff *),
					GFP_KERNEL);
	if (netif_msg_probe(priv)) {
		pr_debug("(%s) dma_rx_phy=0x%08x dma_tx_phy=0x%08x\n", __func__,
			 (u32) priv->dma_rx_phy, (u32) priv->dma_tx_phy);

		/* RX INITIALIZATION */
		pr_debug("\tSKB addresses:\nskb\t\tskb data\tdma data\n");
	}
	for (i = 0; i < rxsize; i++) {
		struct dma_desc *p;
		if (priv->extend_desc)
			p = &((priv->dma_erx + i)->basic);
		else
			p = priv->dma_rx + i;

		if (stmmac_init_rx_buffers(priv, p, i))
			break;

		if (netif_msg_probe(priv))
			pr_debug("[%p]\t[%p]\t[%x]\n", priv->rx_skbuff[i],
				 priv->rx_skbuff[i]->data,
				 (unsigned int)priv->rx_skbuff_dma[i]);
	}
	priv->cur_rx = 0;
	priv->dirty_rx = (unsigned int)(i - rxsize);
	priv->dma_buf_sz = bfsize;
	buf_sz = bfsize;

	/* Setup the chained descriptor addresses */
	if (priv->mode == STMMAC_CHAIN_MODE) {
		if (priv->extend_desc) {
			priv->hw->chain->init(priv->dma_erx, priv->dma_rx_phy,
					      rxsize, 1);
			priv->hw->chain->init(priv->dma_etx, priv->dma_tx_phy,
					      txsize, 1);
		} else {
			priv->hw->chain->init(priv->dma_rx, priv->dma_rx_phy,
					      rxsize, 0);
			priv->hw->chain->init(priv->dma_tx, priv->dma_tx_phy,
					      txsize, 0);
		}
	}

	/* TX INITIALIZATION */
	for (i = 0; i < txsize; i++) {
		struct dma_desc *p;
		if (priv->extend_desc)
			p = &((priv->dma_etx + i)->basic);
		else
			p = priv->dma_tx + i;
		p->des2 = 0;
		priv->tx_skbuff_dma[i] = 0;
		priv->tx_skbuff[i] = NULL;
	}

	priv->dirty_tx = 0;
	priv->cur_tx = 0;

	stmmac_clear_descriptors(priv);

	if (netif_msg_hw(priv))
		stmmac_display_rings(priv);
}

static void dma_free_rx_skbufs(struct stmmac_priv *priv)
{
	int i;

	for (i = 0; i < priv->dma_rx_size; i++) {
		if (priv->rx_skbuff[i]) {
			dma_unmap_single(priv->device, priv->rx_skbuff_dma[i],
					 priv->dma_buf_sz, DMA_FROM_DEVICE);
			dev_kfree_skb_any(priv->rx_skbuff[i]);
		}
		priv->rx_skbuff[i] = NULL;
	}
}

static void dma_free_tx_skbufs(struct stmmac_priv *priv)
{
	int i;

	for (i = 0; i < priv->dma_tx_size; i++) {
		if (priv->tx_skbuff[i] != NULL) {
			struct dma_desc *p;
			if (priv->extend_desc)
				p = &((priv->dma_etx + i)->basic);
			else
				p = priv->dma_tx + i;

			if (priv->tx_skbuff_dma[i])
				dma_unmap_single(priv->device,
						 priv->tx_skbuff_dma[i],
						 priv->hw->desc->get_tx_len(p),
						 DMA_TO_DEVICE);
			dev_kfree_skb_any(priv->tx_skbuff[i]);
			priv->tx_skbuff[i] = NULL;
			priv->tx_skbuff_dma[i] = 0;
		}
	}
}

static void free_dma_desc_resources(struct stmmac_priv *priv)
{
	/* Release the DMA TX/RX socket buffers */
	dma_free_rx_skbufs(priv);
	dma_free_tx_skbufs(priv);

	/* Free DMA regions of consistent memory previously allocated */
	if (!priv->extend_desc) {
		dma_free_coherent(priv->device,
				  priv->dma_tx_size * sizeof(struct dma_desc),
				  priv->dma_tx, priv->dma_tx_phy);
		dma_free_coherent(priv->device,
				  priv->dma_rx_size * sizeof(struct dma_desc),
				  priv->dma_rx, priv->dma_rx_phy);
	} else {
		dma_free_coherent(priv->device, priv->dma_tx_size *
				  sizeof(struct dma_extended_desc),
				  priv->dma_etx, priv->dma_tx_phy);
		dma_free_coherent(priv->device, priv->dma_rx_size *
				  sizeof(struct dma_extended_desc),
				  priv->dma_erx, priv->dma_rx_phy);
	}
	kfree(priv->rx_skbuff_dma);
	kfree(priv->rx_skbuff);
	kfree(priv->tx_skbuff_dma);
	kfree(priv->tx_skbuff);
}

/**
 *  stmmac_dma_operation_mode - HW DMA operation mode
 *  @priv: driver private structure
 *  Description: it sets the DMA operation mode: tx/rx DMA thresholds
 *  or Store-And-Forward capability.
 */
static void stmmac_dma_operation_mode(struct stmmac_priv *priv)
{
	if (likely(priv->plat->force_sf_dma_mode ||
		   ((priv->plat->tx_coe) && (!priv->no_csum_insertion)))) {
		/*
		 * In case of GMAC, SF mode can be enabled
		 * to perform the TX COE in HW. This depends on:
		 * 1) TX COE if actually supported
		 * 2) There is no bugged Jumbo frame support
		 *    that needs to not insert csum in the TDES.
		 */
		priv->hw->dma->dma_mode(priv->ioaddr, SF_DMA_MODE, SF_DMA_MODE);
		tc = SF_DMA_MODE;
	} else
		priv->hw->dma->dma_mode(priv->ioaddr, tc, SF_DMA_MODE);
}

/**
 * stmmac_tx_clean:
 * @priv: driver private structure
 * Description: it reclaims resources after transmission completes.
 */
static void stmmac_tx_clean(struct stmmac_priv *priv)
{
	unsigned int txsize = priv->dma_tx_size;

	spin_lock(&priv->tx_lock);

	priv->xstats.tx_clean++;

	while (priv->dirty_tx != priv->cur_tx) {
		int last;
		unsigned int entry = priv->dirty_tx % txsize;
		struct sk_buff *skb = priv->tx_skbuff[entry];
		struct dma_desc *p;

		if (priv->extend_desc)
			p = (struct dma_desc *)(priv->dma_etx + entry);
		else
			p = priv->dma_tx + entry;

		/* Check if the descriptor is owned by the DMA. */
		if (priv->hw->desc->get_tx_owner(p))
			break;

		/* Verify tx error by looking at the last segment. */
		last = priv->hw->desc->get_tx_ls(p);
		if (likely(last)) {
			int tx_error =
			    priv->hw->desc->tx_status(&priv->dev->stats,
						      &priv->xstats, p,
						      priv->ioaddr);
			if (likely(tx_error == 0)) {
				priv->dev->stats.tx_packets++;
				priv->xstats.tx_pkt_n++;
			} else
				priv->dev->stats.tx_errors++;

			stmmac_get_tx_hwtstamp(priv, entry, skb);
		}
		if (netif_msg_tx_done(priv))
			pr_debug("%s: curr %d, dirty %d\n", __func__,
				 priv->cur_tx, priv->dirty_tx);

		if (likely(priv->tx_skbuff_dma[entry])) {
			dma_unmap_single(priv->device,
					 priv->tx_skbuff_dma[entry],
					 priv->hw->desc->get_tx_len(p),
					 DMA_TO_DEVICE);
			priv->tx_skbuff_dma[entry] = 0;
		}
		priv->hw->ring->clean_desc3(priv, p);

		if (likely(skb != NULL)) {
			dev_kfree_skb(skb);
			priv->tx_skbuff[entry] = NULL;
		}

		priv->hw->desc->release_tx_desc(p, priv->mode);

		priv->dirty_tx++;
	}
	if (unlikely(netif_queue_stopped(priv->dev) &&
		     stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv))) {
		netif_tx_lock(priv->dev);
		if (netif_queue_stopped(priv->dev) &&
		    stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv)) {
			if (netif_msg_tx_done(priv))
				pr_debug("%s: restart transmit\n", __func__);
			netif_wake_queue(priv->dev);
		}
		netif_tx_unlock(priv->dev);
	}

	if ((priv->eee_enabled) && (!priv->tx_path_in_lpi_mode)) {
		stmmac_enable_eee_mode(priv);
		mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_TIMER(eee_timer));
	}
	spin_unlock(&priv->tx_lock);
}

static inline void stmmac_enable_dma_irq(struct stmmac_priv *priv)
{
	priv->hw->dma->enable_dma_irq(priv->ioaddr);
}

static inline void stmmac_disable_dma_irq(struct stmmac_priv *priv)
{
	priv->hw->dma->disable_dma_irq(priv->ioaddr);
}

/**
 * stmmac_tx_err: irq tx error mng function
 * @priv: driver private structure
 * Description: it cleans the descriptors and restarts the transmission
 * in case of errors.
 */
static void stmmac_tx_err(struct stmmac_priv *priv)
{
	int i;
	int txsize = priv->dma_tx_size;
	netif_stop_queue(priv->dev);

	priv->hw->dma->stop_tx(priv->ioaddr);
	dma_free_tx_skbufs(priv);
	for (i = 0; i < txsize; i++)
		if (priv->extend_desc)
			priv->hw->desc->init_tx_desc(&priv->dma_etx[i].basic,
						     priv->mode,
						     (i == txsize - 1));
		else
			priv->hw->desc->init_tx_desc(&priv->dma_tx[i],
						     priv->mode,
						     (i == txsize - 1));
	priv->dirty_tx = 0;
	priv->cur_tx = 0;
	priv->hw->dma->start_tx(priv->ioaddr);

	priv->dev->stats.tx_errors++;
	netif_wake_queue(priv->dev);
}

/**
 * stmmac_dma_interrupt: DMA ISR
 * @priv: driver private structure
 * Description: this is the DMA ISR. It is called by the main ISR.
 * It calls the dwmac dma routine to understand which type of interrupt
 * happened. In case of there is a Normal interrupt and either TX or RX
 * interrupt happened so the NAPI is scheduled.
 */
static void stmmac_dma_interrupt(struct stmmac_priv *priv)
{
	int status;

	status = priv->hw->dma->dma_interrupt(priv->ioaddr, &priv->xstats);
	if (likely((status & handle_rx)) || (status & handle_tx)) {
		if (likely(napi_schedule_prep(&priv->napi))) {
			stmmac_disable_dma_irq(priv);
			__napi_schedule(&priv->napi);
		}
	}
	if (unlikely(status & tx_hard_error_bump_tc)) {
		/* Try to bump up the dma threshold on this failure */
		if (unlikely(tc != SF_DMA_MODE) && (tc <= 256)) {
			tc += 64;
			priv->hw->dma->dma_mode(priv->ioaddr, tc, SF_DMA_MODE);
			priv->xstats.threshold = tc;
		}
	} else if (unlikely(status == tx_hard_error))
		stmmac_tx_err(priv);
}

/**
 * stmmac_mmc_setup: setup the Mac Management Counters (MMC)
 * @priv: driver private structure
 * Description: this masks the MMC irq, in fact, the counters are managed in SW.
 */
static void stmmac_mmc_setup(struct stmmac_priv *priv)
{
	unsigned int mode = MMC_CNTRL_RESET_ON_READ | MMC_CNTRL_COUNTER_RESET |
	    MMC_CNTRL_PRESET | MMC_CNTRL_FULL_HALF_PRESET;

	dwmac_mmc_intr_all_mask(priv->ioaddr);

	if (priv->dma_cap.rmon) {
		dwmac_mmc_ctrl(priv->ioaddr, mode);
		memset(&priv->mmc, 0, sizeof(struct stmmac_counters));
	} else
		pr_info(" No MAC Management Counters available\n");
}

static u32 stmmac_get_synopsys_id(struct stmmac_priv *priv)
{
	u32 hwid = priv->hw->synopsys_uid;

	/* Check Synopsys Id (not available on old chips) */
	if (likely(hwid)) {
		u32 uid = ((hwid & 0x0000ff00) >> 8);
		u32 synid = (hwid & 0x000000ff);

		pr_info("stmmac - user ID: 0x%x, Synopsys ID: 0x%x\n",
			uid, synid);

		return synid;
	}
	return 0;
}

/**
 * stmmac_selec_desc_mode: to select among: normal/alternate/extend descriptors
 * @priv: driver private structure
 * Description: select the Enhanced/Alternate or Normal descriptors.
 * In case of Enhanced/Alternate, it looks at the extended descriptors are
 * supported by the HW cap. register.
 */
static void stmmac_selec_desc_mode(struct stmmac_priv *priv)
{
	if (priv->plat->enh_desc) {
		pr_info(" Enhanced/Alternate descriptors\n");

		/* GMAC older than 3.50 has no extended descriptors */
		if (priv->synopsys_id >= DWMAC_CORE_3_50) {
			pr_info("\tEnabled extended descriptors\n");
			priv->extend_desc = 1;
		} else
			pr_warn("Extended descriptors not supported\n");

		priv->hw->desc = &enh_desc_ops;
	} else {
		pr_info(" Normal descriptors\n");
		priv->hw->desc = &ndesc_ops;
	}
}

/**
 * stmmac_get_hw_features: get MAC capabilities from the HW cap. register.
 * @priv: driver private structure
 * Description:
 *  new GMAC chip generations have a new register to indicate the
 *  presence of the optional feature/functions.
 *  This can be also used to override the value passed through the
 *  platform and necessary for old MAC10/100 and GMAC chips.
 */
static int stmmac_get_hw_features(struct stmmac_priv *priv)
{
	u32 hw_cap = 0;

	if (priv->hw->dma->get_hw_feature) {
		hw_cap = priv->hw->dma->get_hw_feature(priv->ioaddr);

		priv->dma_cap.mbps_10_100 = (hw_cap & DMA_HW_FEAT_MIISEL);
		priv->dma_cap.mbps_1000 = (hw_cap & DMA_HW_FEAT_GMIISEL) >> 1;
		priv->dma_cap.half_duplex = (hw_cap & DMA_HW_FEAT_HDSEL) >> 2;
		priv->dma_cap.hash_filter = (hw_cap & DMA_HW_FEAT_HASHSEL) >> 4;
		priv->dma_cap.multi_addr = (hw_cap & DMA_HW_FEAT_ADDMAC) >> 5;
		priv->dma_cap.pcs = (hw_cap & DMA_HW_FEAT_PCSSEL) >> 6;
		priv->dma_cap.sma_mdio = (hw_cap & DMA_HW_FEAT_SMASEL) >> 8;
		priv->dma_cap.pmt_remote_wake_up =
		    (hw_cap & DMA_HW_FEAT_RWKSEL) >> 9;
		priv->dma_cap.pmt_magic_frame =
		    (hw_cap & DMA_HW_FEAT_MGKSEL) >> 10;
		/* MMC */
		priv->dma_cap.rmon = (hw_cap & DMA_HW_FEAT_MMCSEL) >> 11;
		/* IEEE 1588-2002 */
		priv->dma_cap.time_stamp =
		    (hw_cap & DMA_HW_FEAT_TSVER1SEL) >> 12;
		/* IEEE 1588-2008 */
		priv->dma_cap.atime_stamp =
		    (hw_cap & DMA_HW_FEAT_TSVER2SEL) >> 13;
		/* 802.3az - Energy-Efficient Ethernet (EEE) */
		priv->dma_cap.eee = (hw_cap & DMA_HW_FEAT_EEESEL) >> 14;
		priv->dma_cap.av = (hw_cap & DMA_HW_FEAT_AVSEL) >> 15;
		/* TX and RX csum */
		priv->dma_cap.tx_coe = (hw_cap & DMA_HW_FEAT_TXCOESEL) >> 16;
		priv->dma_cap.rx_coe_type1 =
		    (hw_cap & DMA_HW_FEAT_RXTYP1COE) >> 17;
		priv->dma_cap.rx_coe_type2 =
		    (hw_cap & DMA_HW_FEAT_RXTYP2COE) >> 18;
		priv->dma_cap.rxfifo_over_2048 =
		    (hw_cap & DMA_HW_FEAT_RXFIFOSIZE) >> 19;
		/* TX and RX number of channels */
		priv->dma_cap.number_rx_channel =
		    (hw_cap & DMA_HW_FEAT_RXCHCNT) >> 20;
		priv->dma_cap.number_tx_channel =
		    (hw_cap & DMA_HW_FEAT_TXCHCNT) >> 22;
		/* Alternate (enhanced) DESC mode */
		priv->dma_cap.enh_desc = (hw_cap & DMA_HW_FEAT_ENHDESSEL) >> 24;
	}

	return hw_cap;
}

/**
 * stmmac_check_ether_addr: check if the MAC addr is valid
 * @priv: driver private structure
 * Description:
 * it is to verify if the MAC address is valid, in case of failures it
 * generates a random MAC address
 */
static void stmmac_check_ether_addr(struct stmmac_priv *priv)
{
	if (!is_valid_ether_addr(priv->dev->dev_addr)) {
		priv->hw->mac->get_umac_addr((void __iomem *)
					     priv->dev->base_addr,
					     priv->dev->dev_addr, 0);
		if (!is_valid_ether_addr(priv->dev->dev_addr))
			eth_hw_addr_random(priv->dev);
	}
	pr_warn("%s: device MAC address %pM\n", priv->dev->name,
		priv->dev->dev_addr);
}

/**
 * stmmac_init_dma_engine: DMA init.
 * @priv: driver private structure
 * Description:
 * It inits the DMA invoking the specific MAC/GMAC callback.
 * Some DMA parameters can be passed from the platform;
 * in case of these are not passed a default is kept for the MAC or GMAC.
 */
static int stmmac_init_dma_engine(struct stmmac_priv *priv)
{
	int pbl = DEFAULT_DMA_PBL, fixed_burst = 0, burst_len = 0;
	int mixed_burst = 0;
	int atds = 0;

	if (priv->plat->dma_cfg) {
		pbl = priv->plat->dma_cfg->pbl;
		fixed_burst = priv->plat->dma_cfg->fixed_burst;
		mixed_burst = priv->plat->dma_cfg->mixed_burst;
		burst_len = priv->plat->dma_cfg->burst_len;
	}

	if (priv->extend_desc && (priv->mode == STMMAC_RING_MODE))
		atds = 1;

	return priv->hw->dma->init(priv->ioaddr, pbl, fixed_burst, mixed_burst,
				   burst_len, priv->dma_tx_phy,
				   priv->dma_rx_phy, atds);
}

/**
 * stmmac_tx_timer: mitigation sw timer for tx.
 * @data: data pointer
 * Description:
 * This is the timer handler to directly invoke the stmmac_tx_clean.
 */
static void stmmac_tx_timer(unsigned long data)
{
	struct stmmac_priv *priv = (struct stmmac_priv *)data;

	stmmac_tx_clean(priv);
}

/**
 * stmmac_init_tx_coalesce: init tx mitigation options.
 * @priv: driver private structure
 * Description:
 * This inits the transmit coalesce parameters: i.e. timer rate,
 * timer handler and default threshold used for enabling the
 * interrupt on completion bit.
 */
static void stmmac_init_tx_coalesce(struct stmmac_priv *priv)
{
	priv->tx_coal_frames = STMMAC_TX_FRAMES;
	priv->tx_coal_timer = STMMAC_COAL_TX_TIMER;
	init_timer(&priv->txtimer);
	priv->txtimer.expires = STMMAC_COAL_TIMER(priv->tx_coal_timer);
	priv->txtimer.data = (unsigned long)priv;
	priv->txtimer.function = stmmac_tx_timer;
	add_timer(&priv->txtimer);
}

/**
 *  stmmac_open - open entry point of the driver
 *  @dev : pointer to the device structure.
 *  Description:
 *  This function is the open entry point of the driver.
 *  Return value:
 *  0 on success and an appropriate (-)ve integer as defined in errno.h
 *  file on failure.
 */
static int stmmac_open(struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	int ret;

	clk_prepare_enable(priv->stmmac_clk);

	stmmac_check_ether_addr(priv);

	if (priv->pcs != STMMAC_PCS_RGMII && priv->pcs != STMMAC_PCS_TBI &&
	    priv->pcs != STMMAC_PCS_RTBI) {
		ret = stmmac_init_phy(dev);
		if (ret) {
			pr_err("%s: Cannot attach to PHY (error: %d)\n",
			       __func__, ret);
			goto open_error;
		}
	}

	/* Create and initialize the TX/RX descriptors chains. */
	priv->dma_tx_size = STMMAC_ALIGN(dma_txsize);
	priv->dma_rx_size = STMMAC_ALIGN(dma_rxsize);
	priv->dma_buf_sz = STMMAC_ALIGN(buf_sz);
	init_dma_desc_rings(dev);

	/* DMA initialization and SW reset */
	ret = stmmac_init_dma_engine(priv);
	if (ret < 0) {
		pr_err("%s: DMA initialization failed\n", __func__);
		goto open_error;
	}

	/* Copy the MAC addr into the HW  */
	priv->hw->mac->set_umac_addr(priv->ioaddr, dev->dev_addr, 0);

	/* If required, perform hw setup of the bus. */
	if (priv->plat->bus_setup)
		priv->plat->bus_setup(priv->ioaddr);

	/* Initialize the MAC Core */
	priv->hw->mac->core_init(priv->ioaddr);

	/* Request the IRQ lines */
	ret = request_irq(dev->irq, stmmac_interrupt,
			  IRQF_SHARED, dev->name, dev);
	if (unlikely(ret < 0)) {
		pr_err("%s: ERROR: allocating the IRQ %d (error: %d)\n",
		       __func__, dev->irq, ret);
		goto open_error;
	}

	/* Request the Wake IRQ in case of another line is used for WoL */
	if (priv->wol_irq != dev->irq) {
		ret = request_irq(priv->wol_irq, stmmac_interrupt,
				  IRQF_SHARED, dev->name, dev);
		if (unlikely(ret < 0)) {
			pr_err("%s: ERROR: allocating the WoL IRQ %d (%d)\n",
			       __func__, priv->wol_irq, ret);
			goto open_error_wolirq;
		}
	}

	/* Request the IRQ lines */
	if (priv->lpi_irq != -ENXIO) {
		ret = request_irq(priv->lpi_irq, stmmac_interrupt, IRQF_SHARED,
				  dev->name, dev);
		if (unlikely(ret < 0)) {
			pr_err("%s: ERROR: allocating the LPI IRQ %d (%d)\n",
			       __func__, priv->lpi_irq, ret);
			goto open_error_lpiirq;
		}
	}

	/* Enable the MAC Rx/Tx */
	stmmac_set_mac(priv->ioaddr, true);

	/* Set the HW DMA mode and the COE */
	stmmac_dma_operation_mode(priv);

	/* Extra statistics */
	memset(&priv->xstats, 0, sizeof(struct stmmac_extra_stats));
	priv->xstats.threshold = tc;

	stmmac_mmc_setup(priv);

	ret = stmmac_init_ptp(priv);
	if (ret)
		pr_warn("%s: failed PTP initialisation\n", __func__);

#ifdef CONFIG_STMMAC_DEBUG_FS
	ret = stmmac_init_fs(dev);
	if (ret < 0)
		pr_warn("%s: failed debugFS registration\n", __func__);
#endif
	/* Start the ball rolling... */
	pr_debug("%s: DMA RX/TX processes started...\n", dev->name);
	priv->hw->dma->start_tx(priv->ioaddr);
	priv->hw->dma->start_rx(priv->ioaddr);

	/* Dump DMA/MAC registers */
	if (netif_msg_hw(priv)) {
		priv->hw->mac->dump_regs(priv->ioaddr);
		priv->hw->dma->dump_regs(priv->ioaddr);
	}

	if (priv->phydev)
		phy_start(priv->phydev);

	priv->tx_lpi_timer = STMMAC_DEFAULT_TWT_LS_TIMER;

	/* Using PCS we cannot dial with the phy registers at this stage
	 * so we do not support extra feature like EEE.
	 */
	if (priv->pcs != STMMAC_PCS_RGMII && priv->pcs != STMMAC_PCS_TBI &&
	    priv->pcs != STMMAC_PCS_RTBI)
		priv->eee_enabled = stmmac_eee_init(priv);

	stmmac_init_tx_coalesce(priv);

	if ((priv->use_riwt) && (priv->hw->dma->rx_watchdog)) {
		priv->rx_riwt = MAX_DMA_RIWT;
		priv->hw->dma->rx_watchdog(priv->ioaddr, MAX_DMA_RIWT);
	}

	if (priv->pcs && priv->hw->mac->ctrl_ane)
		priv->hw->mac->ctrl_ane(priv->ioaddr, 0);

	napi_enable(&priv->napi);
	netif_start_queue(dev);

	return 0;

open_error_lpiirq:
	if (priv->wol_irq != dev->irq)
		free_irq(priv->wol_irq, dev);

open_error_wolirq:
	free_irq(dev->irq, dev);

open_error:
	if (priv->phydev)
		phy_disconnect(priv->phydev);

	clk_disable_unprepare(priv->stmmac_clk);

	return ret;
}

/**
 *  stmmac_release - close entry point of the driver
 *  @dev : device pointer.
 *  Description:
 *  This is the stop entry point of the driver.
 */
static int stmmac_release(struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);

	if (priv->eee_enabled)
		del_timer_sync(&priv->eee_ctrl_timer);

	/* Stop and disconnect the PHY */
	if (priv->phydev) {
		phy_stop(priv->phydev);
		phy_disconnect(priv->phydev);
		priv->phydev = NULL;
	}

	netif_stop_queue(dev);

	napi_disable(&priv->napi);

	del_timer_sync(&priv->txtimer);

	/* Free the IRQ lines */
	free_irq(dev->irq, dev);
	if (priv->wol_irq != dev->irq)
		free_irq(priv->wol_irq, dev);
	if (priv->lpi_irq != -ENXIO)
		free_irq(priv->lpi_irq, dev);

	/* Stop TX/RX DMA and clear the descriptors */
	priv->hw->dma->stop_tx(priv->ioaddr);
	priv->hw->dma->stop_rx(priv->ioaddr);

	/* Release and free the Rx/Tx resources */
	free_dma_desc_resources(priv);

	/* Disable the MAC Rx/Tx */
	stmmac_set_mac(priv->ioaddr, false);

	netif_carrier_off(dev);

#ifdef CONFIG_STMMAC_DEBUG_FS
	stmmac_exit_fs();
#endif
	clk_disable_unprepare(priv->stmmac_clk);

	stmmac_release_ptp(priv);

	return 0;
}

/**
 *  stmmac_xmit: Tx entry point of the driver
 *  @skb : the socket buffer
 *  @dev : device pointer
 *  Description : this is the tx entry point of the driver.
 *  It programs the chain or the ring and supports oversized frames
 *  and SG feature.
 */
static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	unsigned int txsize = priv->dma_tx_size;
	unsigned int entry;
	int i, csum_insertion = 0, is_jumbo = 0;
	int nfrags = skb_shinfo(skb)->nr_frags;
	struct dma_desc *desc, *first;
	unsigned int nopaged_len = skb_headlen(skb);

	if (unlikely(stmmac_tx_avail(priv) < nfrags + 1)) {
		if (!netif_queue_stopped(dev)) {
			netif_stop_queue(dev);
			/* This is a hard error, log it. */
			pr_err("%s: Tx Ring full when queue awake\n", __func__);
		}
		return NETDEV_TX_BUSY;
	}

	spin_lock(&priv->tx_lock);

	if (priv->tx_path_in_lpi_mode)
		stmmac_disable_eee_mode(priv);

	entry = priv->cur_tx % txsize;

	csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL);

	if (priv->extend_desc)
		desc = (struct dma_desc *)(priv->dma_etx + entry);
	else
		desc = priv->dma_tx + entry;

	first = desc;

	priv->tx_skbuff[entry] = skb;

	/* To program the descriptors according to the size of the frame */
	if (priv->mode == STMMAC_RING_MODE) {
		is_jumbo = priv->hw->ring->is_jumbo_frm(skb->len,
							priv->plat->enh_desc);
		if (unlikely(is_jumbo))
			entry = priv->hw->ring->jumbo_frm(priv, skb,
							  csum_insertion);
	} else {
		is_jumbo = priv->hw->chain->is_jumbo_frm(skb->len,
							 priv->plat->enh_desc);
		if (unlikely(is_jumbo))
			entry = priv->hw->chain->jumbo_frm(priv, skb,
							   csum_insertion);
	}
	if (likely(!is_jumbo)) {
		desc->des2 = dma_map_single(priv->device, skb->data,
					    nopaged_len, DMA_TO_DEVICE);
		priv->tx_skbuff_dma[entry] = desc->des2;
		priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len,
						csum_insertion, priv->mode);
	} else
		desc = first;

	for (i = 0; i < nfrags; i++) {
		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
		int len = skb_frag_size(frag);

		entry = (++priv->cur_tx) % txsize;
		if (priv->extend_desc)
			desc = (struct dma_desc *)(priv->dma_etx + entry);
		else
			desc = priv->dma_tx + entry;

		desc->des2 = skb_frag_dma_map(priv->device, frag, 0, len,
					      DMA_TO_DEVICE);
		priv->tx_skbuff_dma[entry] = desc->des2;
		priv->tx_skbuff[entry] = NULL;
		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum_insertion,
						priv->mode);
		wmb();
		priv->hw->desc->set_tx_owner(desc);
		wmb();
	}

	/* Finalize the latest segment. */
	priv->hw->desc->close_tx_desc(desc);

	wmb();
	/* According to the coalesce parameter the IC bit for the latest
	 * segment could be reset and the timer re-started to invoke the
	 * stmmac_tx function. This approach takes care about the fragments.
	 */
	priv->tx_count_frames += nfrags + 1;
	if (priv->tx_coal_frames > priv->tx_count_frames) {
		priv->hw->desc->clear_tx_ic(desc);
		priv->xstats.tx_reset_ic_bit++;
		mod_timer(&priv->txtimer,
			  STMMAC_COAL_TIMER(priv->tx_coal_timer));
	} else
		priv->tx_count_frames = 0;

	/* To avoid raise condition */
	priv->hw->desc->set_tx_owner(first);
	wmb();

	priv->cur_tx++;

	if (netif_msg_pktdata(priv)) {
		pr_debug("%s: curr %d dirty=%d entry=%d, first=%p, nfrags=%d",
			__func__, (priv->cur_tx % txsize),
			(priv->dirty_tx % txsize), entry, first, nfrags);

		if (priv->extend_desc)
			stmmac_display_ring((void *)priv->dma_etx, txsize, 1);
		else
			stmmac_display_ring((void *)priv->dma_tx, txsize, 0);

		pr_debug(">>> frame to be transmitted: ");
		print_pkt(skb->data, skb->len);
	}
	if (unlikely(stmmac_tx_avail(priv) <= (MAX_SKB_FRAGS + 1))) {
		if (netif_msg_hw(priv))
			pr_debug("%s: stop transmitted packets\n", __func__);
		netif_stop_queue(dev);
	}

	dev->stats.tx_bytes += skb->len;

	if (unlikely((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
		     priv->hwts_tx_en)) {
		/* declare that device is doing timestamping */
		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
		priv->hw->desc->enable_tx_timestamp(first);
	}

	if (!priv->hwts_tx_en)
		skb_tx_timestamp(skb);

	priv->hw->dma->enable_dma_transmission(priv->ioaddr);

	spin_unlock(&priv->tx_lock);

	return NETDEV_TX_OK;
}

/**
 * stmmac_rx_refill: refill used skb preallocated buffers
 * @priv: driver private structure
 * Description : this is to reallocate the skb for the reception process
 * that is based on zero-copy.
 */
static inline void stmmac_rx_refill(struct stmmac_priv *priv)
{
	unsigned int rxsize = priv->dma_rx_size;
	int bfsize = priv->dma_buf_sz;

	for (; priv->cur_rx - priv->dirty_rx > 0; priv->dirty_rx++) {
		unsigned int entry = priv->dirty_rx % rxsize;
		struct dma_desc *p;

		if (priv->extend_desc)
			p = (struct dma_desc *)(priv->dma_erx + entry);
		else
			p = priv->dma_rx + entry;

		if (likely(priv->rx_skbuff[entry] == NULL)) {
			struct sk_buff *skb;

			skb = netdev_alloc_skb_ip_align(priv->dev, bfsize);

			if (unlikely(skb == NULL))
				break;

			priv->rx_skbuff[entry] = skb;
			priv->rx_skbuff_dma[entry] =
			    dma_map_single(priv->device, skb->data, bfsize,
					   DMA_FROM_DEVICE);

			p->des2 = priv->rx_skbuff_dma[entry];

			priv->hw->ring->refill_desc3(priv, p);

			if (netif_msg_rx_status(priv))
				pr_debug("\trefill entry #%d\n", entry);
		}
		wmb();
		priv->hw->desc->set_rx_owner(p);
		wmb();
	}
}

/**
 * stmmac_rx_refill: refill used skb preallocated buffers
 * @priv: driver private structure
 * @limit: napi bugget.
 * Description :  this the function called by the napi poll method.
 * It gets all the frames inside the ring.
 */
static int stmmac_rx(struct stmmac_priv *priv, int limit)
{
	unsigned int rxsize = priv->dma_rx_size;
	unsigned int entry = priv->cur_rx % rxsize;
	unsigned int next_entry;
	unsigned int count = 0;
	int coe = priv->plat->rx_coe;

	if (netif_msg_rx_status(priv)) {
		pr_debug("%s: descriptor ring:\n", __func__);
		if (priv->extend_desc)
			stmmac_display_ring((void *)priv->dma_erx, rxsize, 1);
		else
			stmmac_display_ring((void *)priv->dma_rx, rxsize, 0);
	}
	while (count < limit) {
		int status;
		struct dma_desc *p;

		if (priv->extend_desc)
			p = (struct dma_desc *)(priv->dma_erx + entry);
		else
			p = priv->dma_rx + entry;

		if (priv->hw->desc->get_rx_owner(p))
			break;

		count++;

		next_entry = (++priv->cur_rx) % rxsize;
		if (priv->extend_desc)
			prefetch(priv->dma_erx + next_entry);
		else
			prefetch(priv->dma_rx + next_entry);

		/* read the status of the incoming frame */
		status = priv->hw->desc->rx_status(&priv->dev->stats,
						   &priv->xstats, p);
		if ((priv->extend_desc) && (priv->hw->desc->rx_extended_status))
			priv->hw->desc->rx_extended_status(&priv->dev->stats,
							   &priv->xstats,
							   priv->dma_erx +
							   entry);
		if (unlikely(status == discard_frame)) {
			priv->dev->stats.rx_errors++;
			if (priv->hwts_rx_en && !priv->extend_desc) {
				/* DESC2 & DESC3 will be overwitten by device
				 * with timestamp value, hence reinitialize
				 * them in stmmac_rx_refill() function so that
				 * device can reuse it.
				 */
				priv->rx_skbuff[entry] = NULL;
				dma_unmap_single(priv->device,
						 priv->rx_skbuff_dma[entry],
						 priv->dma_buf_sz,
						 DMA_FROM_DEVICE);
			}
		} else {
			struct sk_buff *skb;
			int frame_len;

			frame_len = priv->hw->desc->get_rx_frame_len(p, coe);

			/* ACS is set; GMAC core strips PAD/FCS for IEEE 802.3
			 * Type frames (LLC/LLC-SNAP)
			 */
			if (unlikely(status != llc_snap))
				frame_len -= ETH_FCS_LEN;

			if (netif_msg_rx_status(priv)) {
				pr_debug("\tdesc: %p [entry %d] buff=0x%x\n",
					 p, entry, p->des2);
				if (frame_len > ETH_FRAME_LEN)
					pr_debug("\tframe size %d, COE: %d\n",
						 frame_len, status);
			}
			skb = priv->rx_skbuff[entry];
			if (unlikely(!skb)) {
				pr_err("%s: Inconsistent Rx descriptor chain\n",
				       priv->dev->name);
				priv->dev->stats.rx_dropped++;
				break;
			}
			prefetch(skb->data - NET_IP_ALIGN);
			priv->rx_skbuff[entry] = NULL;

			stmmac_get_rx_hwtstamp(priv, entry, skb);

			skb_put(skb, frame_len);
			dma_unmap_single(priv->device,
					 priv->rx_skbuff_dma[entry],
					 priv->dma_buf_sz, DMA_FROM_DEVICE);

			if (netif_msg_pktdata(priv)) {
				pr_debug("frame received (%dbytes)", frame_len);
				print_pkt(skb->data, frame_len);
			}

			skb->protocol = eth_type_trans(skb, priv->dev);

			if (unlikely(!coe))
				skb_checksum_none_assert(skb);
			else
				skb->ip_summed = CHECKSUM_UNNECESSARY;

			napi_gro_receive(&priv->napi, skb);

			priv->dev->stats.rx_packets++;
			priv->dev->stats.rx_bytes += frame_len;
		}
		entry = next_entry;
	}

	stmmac_rx_refill(priv);

	priv->xstats.rx_pkt_n += count;

	return count;
}

/**
 *  stmmac_poll - stmmac poll method (NAPI)
 *  @napi : pointer to the napi structure.
 *  @budget : maximum number of packets that the current CPU can receive from
 *	      all interfaces.
 *  Description :
 *  To look at the incoming frames and clear the tx resources.
 */
static int stmmac_poll(struct napi_struct *napi, int budget)
{
	struct stmmac_priv *priv = container_of(napi, struct stmmac_priv, napi);
	int work_done = 0;

	priv->xstats.napi_poll++;
	stmmac_tx_clean(priv);

	work_done = stmmac_rx(priv, budget);
	if (work_done < budget) {
		napi_complete(napi);
		stmmac_enable_dma_irq(priv);
	}
	return work_done;
}

/**
 *  stmmac_tx_timeout
 *  @dev : Pointer to net device structure
 *  Description: this function is called when a packet transmission fails to
 *   complete within a reasonable time. The driver will mark the error in the
 *   netdev structure and arrange for the device to be reset to a sane state
 *   in order to transmit a new packet.
 */
static void stmmac_tx_timeout(struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);

	/* Clear Tx resources and restart transmitting again */
	stmmac_tx_err(priv);
}

/* Configuration changes (passed on by ifconfig) */
static int stmmac_config(struct net_device *dev, struct ifmap *map)
{
	if (dev->flags & IFF_UP)	/* can't act on a running interface */
		return -EBUSY;

	/* Don't allow changing the I/O address */
	if (map->base_addr != dev->base_addr) {
		pr_warn("%s: can't change I/O address\n", dev->name);
		return -EOPNOTSUPP;
	}

	/* Don't allow changing the IRQ */
	if (map->irq != dev->irq) {
		pr_warn("%s: not change IRQ number %d\n", dev->name, dev->irq);
		return -EOPNOTSUPP;
	}

	return 0;
}

/**
 *  stmmac_set_rx_mode - entry point for multicast addressing
 *  @dev : pointer to the device structure
 *  Description:
 *  This function is a driver entry point which gets called by the kernel
 *  whenever multicast addresses must be enabled/disabled.
 *  Return value:
 *  void.
 */
static void stmmac_set_rx_mode(struct net_device *dev)
{
	struct stmmac_priv *priv = netdev_priv(dev);

	spin_lock(&priv->lock);
	priv->hw->mac->set_filter(dev, priv->synopsys_id);
	spin_unlock(&priv->lock);
}

/**
 *  stmmac_change_mtu - entry point to change MTU size for the device.
 *  @dev : device pointer.
 *  @new_mtu : the new MTU size for the device.
 *  Description: the Maximum Transfer Unit (MTU) is used by the network layer
 *  to drive packet transmission. Ethernet has an MTU of 1500 octets
 *  (ETH_DATA_LEN). This value can be changed with ifconfig.
 *  Return value:
 *  0 on success and an appropriate (-)ve integer as defined in errno.h
 *  file on failure.
 */
static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	int max_mtu;

	if (netif_running(dev)) {
		pr_err("%s: must be stopped to change its MTU\n", dev->name);
		return -EBUSY;
	}

	if (priv->plat->enh_desc)
		max_mtu = JUMBO_LEN;
	else
		max_mtu = SKB_MAX_HEAD(NET_SKB_PAD + NET_IP_ALIGN);

	if ((new_mtu < 46) || (new_mtu > max_mtu)) {
		pr_err("%s: invalid MTU, max MTU is: %d\n", dev->name, max_mtu);
		return -EINVAL;
	}

	dev->mtu = new_mtu;
	netdev_update_features(dev);

	return 0;
}

static netdev_features_t stmmac_fix_features(struct net_device *dev,
					     netdev_features_t features)
{
	struct stmmac_priv *priv = netdev_priv(dev);

	if (priv->plat->rx_coe == STMMAC_RX_COE_NONE)
		features &= ~NETIF_F_RXCSUM;
	else if (priv->plat->rx_coe == STMMAC_RX_COE_TYPE1)
		features &= ~NETIF_F_IPV6_CSUM;
	if (!priv->plat->tx_coe)
		features &= ~NETIF_F_ALL_CSUM;

	/* Some GMAC devices have a bugged Jumbo frame support that
	 * needs to have the Tx COE disabled for oversized frames
	 * (due to limited buffer sizes). In this case we disable
	 * the TX csum insertionin the TDES and not use SF.
	 */
	if (priv->plat->bugged_jumbo && (dev->mtu > ETH_DATA_LEN))
		features &= ~NETIF_F_ALL_CSUM;

	return features;
}

/**
 *  stmmac_interrupt - main ISR
 *  @irq: interrupt number.
 *  @dev_id: to pass the net device pointer.
 *  Description: this is the main driver interrupt service routine.
 *  It calls the DMA ISR and also the core ISR to manage PMT, MMC, LPI
 *  interrupts.
 */
static irqreturn_t stmmac_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = (struct net_device *)dev_id;
	struct stmmac_priv *priv = netdev_priv(dev);

	if (unlikely(!dev)) {
		pr_err("%s: invalid dev pointer\n", __func__);
		return IRQ_NONE;
	}

	/* To handle GMAC own interrupts */
	if (priv->plat->has_gmac) {
		int status = priv->hw->mac->host_irq_status((void __iomem *)
							    dev->base_addr,
							    &priv->xstats);
		if (unlikely(status)) {
			/* For LPI we need to save the tx status */
			if (status & CORE_IRQ_TX_PATH_IN_LPI_MODE)
				priv->tx_path_in_lpi_mode = true;
			if (status & CORE_IRQ_TX_PATH_EXIT_LPI_MODE)
				priv->tx_path_in_lpi_mode = false;
		}
	}

	/* To handle DMA interrupts */
	stmmac_dma_interrupt(priv);

	return IRQ_HANDLED;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/* Polling receive - used by NETCONSOLE and other diagnostic tools
 * to allow network I/O with interrupts disabled.
 */
static void stmmac_poll_controller(struct net_device *dev)
{
	disable_irq(dev->irq);
	stmmac_interrupt(dev->irq, dev);
	enable_irq(dev->irq);
}
#endif

/**
 *  stmmac_ioctl - Entry point for the Ioctl
 *  @dev: Device pointer.
 *  @rq: An IOCTL specefic structure, that can contain a pointer to
 *  a proprietary structure used to pass information to the driver.
 *  @cmd: IOCTL command
 *  Description:
 *  Currently it supports the phy_mii_ioctl(...) and HW time stamping.
 */
static int stmmac_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	struct stmmac_priv *priv = netdev_priv(dev);
	int ret = -EOPNOTSUPP;

	if (!netif_running(dev))
		return -EINVAL;

	switch (cmd) {
	case SIOCGMIIPHY:
	case SIOCGMIIREG:
	case SIOCSMIIREG:
		if (!priv->phydev)
			return -EINVAL;
		ret = phy_mii_ioctl(priv->phydev, rq, cmd);
		break;
	case SIOCSHWTSTAMP:
		ret = stmmac_hwtstamp_ioctl(dev, rq);
		break;
	default:
		break;
	}

	return ret;
}

#ifdef CONFIG_STMMAC_DEBUG_FS
static struct dentry *stmmac_fs_dir;
static struct dentry *stmmac_rings_status;
static struct dentry *stmmac_dma_cap;

static void sysfs_display_ring(void *head, int size, int extend_desc,
			       struct seq_file *seq)
{
	int i;
	struct dma_extended_desc *ep = (struct dma_extended_desc *)head;
	struct dma_desc *p = (struct dma_desc *)head;

	for (i = 0; i < size; i++) {
		u64 x;
		if (extend_desc) {
			x = *(u64 *) ep;
			seq_printf(seq, "%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
				   i, (unsigned int)virt_to_phys(ep),
				   (unsigned int)x, (unsigned int)(x >> 32),
				   ep->basic.des2, ep->basic.des3);
			ep++;
		} else {
			x = *(u64 *) p;
			seq_printf(seq, "%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
				   i, (unsigned int)virt_to_phys(ep),
				   (unsigned int)x, (unsigned int)(x >> 32),
				   p->des2, p->des3);
			p++;
		}
		seq_printf(seq, "\n");
	}
}

static int stmmac_sysfs_ring_read(struct seq_file *seq, void *v)
{
	struct net_device *dev = seq->private;
	struct stmmac_priv *priv = netdev_priv(dev);
	unsigned int txsize = priv->dma_tx_size;
	unsigned int rxsize = priv->dma_rx_size;

	if (priv->extend_desc) {
		seq_printf(seq, "Extended RX descriptor ring:\n");
		sysfs_display_ring((void *)priv->dma_erx, rxsize, 1, seq);
		seq_printf(seq, "Extended TX descriptor ring:\n");
		sysfs_display_ring((void *)priv->dma_etx, txsize, 1, seq);
	} else {
		seq_printf(seq, "RX descriptor ring:\n");
		sysfs_display_ring((void *)priv->dma_rx, rxsize, 0, seq);
		seq_printf(seq, "TX descriptor ring:\n");
		sysfs_display_ring((void *)priv->dma_tx, txsize, 0, seq);
	}

	return 0;
}

static int stmmac_sysfs_ring_open(struct inode *inode, struct file *file)
{
	return single_open(file, stmmac_sysfs_ring_read, inode->i_private);
}

static const struct file_operations stmmac_rings_status_fops = {
	.owner = THIS_MODULE,
	.open = stmmac_sysfs_ring_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int stmmac_sysfs_dma_cap_read(struct seq_file *seq, void *v)
{
	struct net_device *dev = seq->private;
	struct stmmac_priv *priv = netdev_priv(dev);

	if (!priv->hw_cap_support) {
		seq_printf(seq, "DMA HW features not supported\n");
		return 0;
	}

	seq_printf(seq, "==============================\n");
	seq_printf(seq, "\tDMA HW features\n");
	seq_printf(seq, "==============================\n");

	seq_printf(seq, "\t10/100 Mbps %s\n",
		   (priv->dma_cap.mbps_10_100) ? "Y" : "N");
	seq_printf(seq, "\t1000 Mbps %s\n",
		   (priv->dma_cap.mbps_1000) ? "Y" : "N");
	seq_printf(seq, "\tHalf duple %s\n",
		   (priv->dma_cap.half_duplex) ? "Y" : "N");
	seq_printf(seq, "\tHash Filter: %s\n",
		   (priv->dma_cap.hash_filter) ? "Y" : "N");
	seq_printf(seq, "\tMultiple MAC address registers: %s\n",
		   (priv->dma_cap.multi_addr) ? "Y" : "N");
	seq_printf(seq, "\tPCS (TBI/SGMII/RTBI PHY interfatces): %s\n",
		   (priv->dma_cap.pcs) ? "Y" : "N");
	seq_printf(seq, "\tSMA (MDIO) Interface: %s\n",
		   (priv->dma_cap.sma_mdio) ? "Y" : "N");
	seq_printf(seq, "\tPMT Remote wake up: %s\n",
		   (priv->dma_cap.pmt_remote_wake_up) ? "Y" : "N");
	seq_printf(seq, "\tPMT Magic Frame: %s\n",
		   (priv->dma_cap.pmt_magic_frame) ? "Y" : "N");
	seq_printf(seq, "\tRMON module: %s\n",
		   (priv->dma_cap.rmon) ? "Y" : "N");
	seq_printf(seq, "\tIEEE 1588-2002 Time Stamp: %s\n",
		   (priv->dma_cap.time_stamp) ? "Y" : "N");
	seq_printf(seq, "\tIEEE 1588-2008 Advanced Time Stamp:%s\n",
		   (priv->dma_cap.atime_stamp) ? "Y" : "N");
	seq_printf(seq, "\t802.3az - Energy-Efficient Ethernet (EEE) %s\n",
		   (priv->dma_cap.eee) ? "Y" : "N");
	seq_printf(seq, "\tAV features: %s\n", (priv->dma_cap.av) ? "Y" : "N");
	seq_printf(seq, "\tChecksum Offload in TX: %s\n",
		   (priv->dma_cap.tx_coe) ? "Y" : "N");
	seq_printf(seq, "\tIP Checksum Offload (type1) in RX: %s\n",
		   (priv->dma_cap.rx_coe_type1) ? "Y" : "N");
	seq_printf(seq, "\tIP Checksum Offload (type2) in RX: %s\n",
		   (priv->dma_cap.rx_coe_type2) ? "Y" : "N");
	seq_printf(seq, "\tRXFIFO > 2048bytes: %s\n",
		   (priv->dma_cap.rxfifo_over_2048) ? "Y" : "N");
	seq_printf(seq, "\tNumber of Additional RX channel: %d\n",
		   priv->dma_cap.number_rx_channel);
	seq_printf(seq, "\tNumber of Additional TX channel: %d\n",
		   priv->dma_cap.number_tx_channel);
	seq_printf(seq, "\tEnhanced descriptors: %s\n",
		   (priv->dma_cap.enh_desc) ? "Y" : "N");

	return 0;
}

static int stmmac_sysfs_dma_cap_open(struct inode *inode, struct file *file)
{
	return single_open(file, stmmac_sysfs_dma_cap_read, inode->i_private);
}

static const struct file_operations stmmac_dma_cap_fops = {
	.owner = THIS_MODULE,
	.open = stmmac_sysfs_dma_cap_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static int stmmac_init_fs(struct net_device *dev)
{
	/* Create debugfs entries */
	stmmac_fs_dir = debugfs_create_dir(STMMAC_RESOURCE_NAME, NULL);

	if (!stmmac_fs_dir || IS_ERR(stmmac_fs_dir)) {
		pr_err("ERROR %s, debugfs create directory failed\n",
		       STMMAC_RESOURCE_NAME);

		return -ENOMEM;
	}

	/* Entry to report DMA RX/TX rings */
	stmmac_rings_status = debugfs_create_file("descriptors_status",
						  S_IRUGO, stmmac_fs_dir, dev,
						  &stmmac_rings_status_fops);

	if (!stmmac_rings_status || IS_ERR(stmmac_rings_status)) {
		pr_info("ERROR creating stmmac ring debugfs file\n");
		debugfs_remove(stmmac_fs_dir);

		return -ENOMEM;
	}

	/* Entry to report the DMA HW features */
	stmmac_dma_cap = debugfs_create_file("dma_cap", S_IRUGO, stmmac_fs_dir,
					     dev, &stmmac_dma_cap_fops);

	if (!stmmac_dma_cap || IS_ERR(stmmac_dma_cap)) {
		pr_info("ERROR creating stmmac MMC debugfs file\n");
		debugfs_remove(stmmac_rings_status);
		debugfs_remove(stmmac_fs_dir);

		return -ENOMEM;
	}

	return 0;
}

static void stmmac_exit_fs(void)
{
	debugfs_remove(stmmac_rings_status);
	debugfs_remove(stmmac_dma_cap);
	debugfs_remove(stmmac_fs_dir);
}
#endif /* CONFIG_STMMAC_DEBUG_FS */

static const struct net_device_ops stmmac_netdev_ops = {
	.ndo_open = stmmac_open,
	.ndo_start_xmit = stmmac_xmit,
	.ndo_stop = stmmac_release,
	.ndo_change_mtu = stmmac_change_mtu,
	.ndo_fix_features = stmmac_fix_features,
	.ndo_set_rx_mode = stmmac_set_rx_mode,
	.ndo_tx_timeout = stmmac_tx_timeout,
	.ndo_do_ioctl = stmmac_ioctl,
	.ndo_set_config = stmmac_config,
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller = stmmac_poll_controller,
#endif
	.ndo_set_mac_address = eth_mac_addr,
};

/**
 *  stmmac_hw_init - Init the MAC device
 *  @priv: driver private structure
 *  Description: this function detects which MAC device
 *  (GMAC/MAC10-100) has to attached, checks the HW capability
 *  (if supported) and sets the driver's features (for example
 *  to use the ring or chaine mode or support the normal/enh
 *  descriptor structure).
 */
static int stmmac_hw_init(struct stmmac_priv *priv)
{
	int ret;
	struct mac_device_info *mac;

	/* Identify the MAC HW device */
	if (priv->plat->has_gmac) {
		priv->dev->priv_flags |= IFF_UNICAST_FLT;
		mac = dwmac1000_setup(priv->ioaddr);
	} else {
		mac = dwmac100_setup(priv->ioaddr);
	}
	if (!mac)
		return -ENOMEM;

	priv->hw = mac;

	/* Get and dump the chip ID */
	priv->synopsys_id = stmmac_get_synopsys_id(priv);

	/* To use the chained or ring mode */
	if (chain_mode) {
		priv->hw->chain = &chain_mode_ops;
		pr_info(" Chain mode enabled\n");
		priv->mode = STMMAC_CHAIN_MODE;
	} else {
		priv->hw->ring = &ring_mode_ops;
		pr_info(" Ring mode enabled\n");
		priv->mode = STMMAC_RING_MODE;
	}

	/* Get the HW capability (new GMAC newer than 3.50a) */
	priv->hw_cap_support = stmmac_get_hw_features(priv);
	if (priv->hw_cap_support) {
		pr_info(" DMA HW capability register supported");

		/* We can override some gmac/dma configuration fields: e.g.
		 * enh_desc, tx_coe (e.g. that are passed through the
		 * platform) with the values from the HW capability
		 * register (if supported).
		 */
		priv->plat->enh_desc = priv->dma_cap.enh_desc;
		priv->plat->pmt = priv->dma_cap.pmt_remote_wake_up;

		priv->plat->tx_coe = priv->dma_cap.tx_coe;

		if (priv->dma_cap.rx_coe_type2)
			priv->plat->rx_coe = STMMAC_RX_COE_TYPE2;
		else if (priv->dma_cap.rx_coe_type1)
			priv->plat->rx_coe = STMMAC_RX_COE_TYPE1;

	} else
		pr_info(" No HW DMA feature register supported");

	/* To use alternate (extended) or normal descriptor structures */
	stmmac_selec_desc_mode(priv);

	ret = priv->hw->mac->rx_ipc(priv->ioaddr);
	if (!ret) {
		pr_warn(" RX IPC Checksum Offload not configured.\n");
		priv->plat->rx_coe = STMMAC_RX_COE_NONE;
	}

	if (priv->plat->rx_coe)
		pr_info(" RX Checksum Offload Engine supported (type %d)\n",
			priv->plat->rx_coe);
	if (priv->plat->tx_coe)
		pr_info(" TX Checksum insertion supported\n");

	if (priv->plat->pmt) {
		pr_info(" Wake-Up On Lan supported\n");
		device_set_wakeup_capable(priv->device, 1);
	}

	return 0;
}

/**
 * stmmac_dvr_probe
 * @device: device pointer
 * @plat_dat: platform data pointer
 * @addr: iobase memory address
 * Description: this is the main probe function used to
 * call the alloc_etherdev, allocate the priv structure.
 */
struct stmmac_priv *stmmac_dvr_probe(struct device *device,
				     struct plat_stmmacenet_data *plat_dat,
				     void __iomem *addr)
{
	int ret = 0;
	struct net_device *ndev = NULL;
	struct stmmac_priv *priv;

	ndev = alloc_etherdev(sizeof(struct stmmac_priv));
	if (!ndev)
		return NULL;

	SET_NETDEV_DEV(ndev, device);

	priv = netdev_priv(ndev);
	priv->device = device;
	priv->dev = ndev;

	ether_setup(ndev);

	stmmac_set_ethtool_ops(ndev);
	priv->pause = pause;
	priv->plat = plat_dat;
	priv->ioaddr = addr;
	priv->dev->base_addr = (unsigned long)addr;

	/* Verify driver arguments */
	stmmac_verify_args();

	/* Override with kernel parameters if supplied XXX CRS XXX
	 * this needs to have multiple instances
	 */
	if ((phyaddr >= 0) && (phyaddr <= 31))
		priv->plat->phy_addr = phyaddr;

	/* Init MAC and get the capabilities */
	ret = stmmac_hw_init(priv);
	if (ret)
		goto error_free_netdev;

	ndev->netdev_ops = &stmmac_netdev_ops;

	ndev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
			    NETIF_F_RXCSUM;
	ndev->features |= ndev->hw_features | NETIF_F_HIGHDMA;
	ndev->watchdog_timeo = msecs_to_jiffies(watchdog);
#ifdef STMMAC_VLAN_TAG_USED
	/* Both mac100 and gmac support receive VLAN tag detection */
	ndev->features |= NETIF_F_HW_VLAN_CTAG_RX;
#endif
	priv->msg_enable = netif_msg_init(debug, default_msg_level);

	if (flow_ctrl)
		priv->flow_ctrl = FLOW_AUTO;	/* RX/TX pause on */

	/* Rx Watchdog is available in the COREs newer than the 3.40.
	 * In some case, for example on bugged HW this feature
	 * has to be disable and this can be done by passing the
	 * riwt_off field from the platform.
	 */
	if ((priv->synopsys_id >= DWMAC_CORE_3_50) && (!priv->plat->riwt_off)) {
		priv->use_riwt = 1;
		pr_info(" Enable RX Mitigation via HW Watchdog Timer\n");
	}

	netif_napi_add(ndev, &priv->napi, stmmac_poll, 64);

	spin_lock_init(&priv->lock);
	spin_lock_init(&priv->tx_lock);

	ret = register_netdev(ndev);
	if (ret) {
		pr_err("%s: ERROR %i registering the device\n", __func__, ret);
		goto error_netdev_register;
	}

	priv->stmmac_clk = clk_get(priv->device, STMMAC_RESOURCE_NAME);
	if (IS_ERR(priv->stmmac_clk)) {
		pr_warn("%s: warning: cannot get CSR clock\n", __func__);
		goto error_clk_get;
	}

	/* If a specific clk_csr value is passed from the platform
	 * this means that the CSR Clock Range selection cannot be
	 * changed at run-time and it is fixed. Viceversa the driver'll try to
	 * set the MDC clock dynamically according to the csr actual
	 * clock input.
	 */
	if (!priv->plat->clk_csr)
		stmmac_clk_csr_set(priv);
	else
		priv->clk_csr = priv->plat->clk_csr;

	stmmac_check_pcs_mode(priv);

	if (priv->pcs != STMMAC_PCS_RGMII && priv->pcs != STMMAC_PCS_TBI &&
	    priv->pcs != STMMAC_PCS_RTBI) {
		/* MDIO bus Registration */
		ret = stmmac_mdio_register(ndev);
		if (ret < 0) {
			pr_debug("%s: MDIO bus (id: %d) registration failed",
				 __func__, priv->plat->bus_id);
			goto error_mdio_register;
		}
	}

	return priv;

error_mdio_register:
	clk_put(priv->stmmac_clk);
error_clk_get:
	unregister_netdev(ndev);
error_netdev_register:
	netif_napi_del(&priv->napi);
error_free_netdev:
	free_netdev(ndev);

	return NULL;
}

/**
 * stmmac_dvr_remove
 * @ndev: net device pointer
 * Description: this function resets the TX/RX processes, disables the MAC RX/TX
 * changes the link status, releases the DMA descriptor rings.
 */
int stmmac_dvr_remove(struct net_device *ndev)
{
	struct stmmac_priv *priv = netdev_priv(ndev);

	pr_info("%s:\n\tremoving driver", __func__);

	priv->hw->dma->stop_rx(priv->ioaddr);
	priv->hw->dma->stop_tx(priv->ioaddr);

	stmmac_set_mac(priv->ioaddr, false);
	if (priv->pcs != STMMAC_PCS_RGMII && priv->pcs != STMMAC_PCS_TBI &&
	    priv->pcs != STMMAC_PCS_RTBI)
		stmmac_mdio_unregister(ndev);
	netif_carrier_off(ndev);
	unregister_netdev(ndev);
	free_netdev(ndev);

	return 0;
}

#ifdef CONFIG_PM
int stmmac_suspend(struct net_device *ndev)
{
	struct stmmac_priv *priv = netdev_priv(ndev);
	unsigned long flags;

	if (!ndev || !netif_running(ndev))
		return 0;

	if (priv->phydev)
		phy_stop(priv->phydev);

	spin_lock_irqsave(&priv->lock, flags);

	netif_device_detach(ndev);
	netif_stop_queue(ndev);

	napi_disable(&priv->napi);

	/* Stop TX/RX DMA */
	priv->hw->dma->stop_tx(priv->ioaddr);
	priv->hw->dma->stop_rx(priv->ioaddr);

	stmmac_clear_descriptors(priv);

	/* Enable Power down mode by programming the PMT regs */
	if (device_may_wakeup(priv->device))
		priv->hw->mac->pmt(priv->ioaddr, priv->wolopts);
	else {
		stmmac_set_mac(priv->ioaddr, false);
		/* Disable clock in case of PWM is off */
		clk_disable_unprepare(priv->stmmac_clk);
	}
	spin_unlock_irqrestore(&priv->lock, flags);
	return 0;
}

int stmmac_resume(struct net_device *ndev)
{
	struct stmmac_priv *priv = netdev_priv(ndev);
	unsigned long flags;

	if (!netif_running(ndev))
		return 0;

	spin_lock_irqsave(&priv->lock, flags);

	/* Power Down bit, into the PM register, is cleared
	 * automatically as soon as a magic packet or a Wake-up frame
	 * is received. Anyway, it's better to manually clear
	 * this bit because it can generate problems while resuming
	 * from another devices (e.g. serial console).
	 */
	if (device_may_wakeup(priv->device))
		priv->hw->mac->pmt(priv->ioaddr, 0);
	else
		/* enable the clk prevously disabled */
		clk_prepare_enable(priv->stmmac_clk);

	netif_device_attach(ndev);

	/* Enable the MAC and DMA */
	stmmac_set_mac(priv->ioaddr, true);
	priv->hw->dma->start_tx(priv->ioaddr);
	priv->hw->dma->start_rx(priv->ioaddr);

	napi_enable(&priv->napi);

	netif_start_queue(ndev);

	spin_unlock_irqrestore(&priv->lock, flags);

	if (priv->phydev)
		phy_start(priv->phydev);

	return 0;
}

int stmmac_freeze(struct net_device *ndev)
{
	if (!ndev || !netif_running(ndev))
		return 0;

	return stmmac_release(ndev);
}

int stmmac_restore(struct net_device *ndev)
{
	if (!ndev || !netif_running(ndev))
		return 0;

	return stmmac_open(ndev);
}
#endif /* CONFIG_PM */

/* Driver can be configured w/ and w/ both PCI and Platf drivers
 * depending on the configuration selected.
 */
static int __init stmmac_init(void)
{
	int ret;

	ret = stmmac_register_platform();
	if (ret)
		goto err;
	ret = stmmac_register_pci();
	if (ret)
		goto err_pci;
	return 0;
err_pci:
	stmmac_unregister_platform();
err:
	pr_err("stmmac: driver registration failed\n");
	return ret;
}

static void __exit stmmac_exit(void)
{
	stmmac_unregister_platform();
	stmmac_unregister_pci();
}

module_init(stmmac_init);
module_exit(stmmac_exit);

#ifndef MODULE
static int __init stmmac_cmdline_opt(char *str)
{
	char *opt;

	if (!str || !*str)
		return -EINVAL;
	while ((opt = strsep(&str, ",")) != NULL) {
		if (!strncmp(opt, "debug:", 6)) {
			if (kstrtoint(opt + 6, 0, &debug))
				goto err;
		} else if (!strncmp(opt, "phyaddr:", 8)) {
			if (kstrtoint(opt + 8, 0, &phyaddr))
				goto err;
		} else if (!strncmp(opt, "dma_txsize:", 11)) {
			if (kstrtoint(opt + 11, 0, &dma_txsize))
				goto err;
		} else if (!strncmp(opt, "dma_rxsize:", 11)) {
			if (kstrtoint(opt + 11, 0, &dma_rxsize))
				goto err;
		} else if (!strncmp(opt, "buf_sz:", 7)) {
			if (kstrtoint(opt + 7, 0, &buf_sz))
				goto err;
		} else if (!strncmp(opt, "tc:", 3)) {
			if (kstrtoint(opt + 3, 0, &tc))
				goto err;
		} else if (!strncmp(opt, "watchdog:", 9)) {
			if (kstrtoint(opt + 9, 0, &watchdog))
				goto err;
		} else if (!strncmp(opt, "flow_ctrl:", 10)) {
			if (kstrtoint(opt + 10, 0, &flow_ctrl))
				goto err;
		} else if (!strncmp(opt, "pause:", 6)) {
			if (kstrtoint(opt + 6, 0, &pause))
				goto err;
		} else if (!strncmp(opt, "eee_timer:", 10)) {
			if (kstrtoint(opt + 10, 0, &eee_timer))
				goto err;
		} else if (!strncmp(opt, "chain_mode:", 11)) {
			if (kstrtoint(opt + 11, 0, &chain_mode))
				goto err;
		}
	}
	return 0;

err:
	pr_err("%s: ERROR broken module parameter conversion", __func__);
	return -EINVAL;
}

__setup("stmmaceth=", stmmac_cmdline_opt);
#endif /* MODULE */

MODULE_DESCRIPTION("STMMAC 10/100/1000 Ethernet device driver");
MODULE_AUTHOR("Giuseppe Cavallaro <peppe.cavallaro@st.com>");
MODULE_LICENSE("GPL");