fec.c

/*
 * Fast Ethernet Controller (FEC) driver for Motorola MPC8xx.
 * Copyright (c) 1997 Dan Malek (dmalek@jlc.net)
 *
 * Right now, I am very wasteful with the buffers.  I allocate memory
 * pages and then divide them into 2K frame buffers.  This way I know I
 * have buffers large enough to hold one frame within one buffer descriptor.
 * Once I get this working, I will use 64 or 128 byte CPM buffers, which
 * will be much more memory efficient and will easily handle lots of
 * small packets.
 *
 * Much better multiple PHY support by Magnus Damm.
 * Copyright (c) 2000 Ericsson Radio Systems AB.
 *
 * Support for FEC controller of ColdFire processors.
 * Copyright (c) 2001-2005 Greg Ungerer (gerg@snapgear.com)
 *
 * Bug fixes and cleanup by Philippe De Muyter (phdm@macqel.be)
 * Copyright (c) 2004-2006 Macq Electronique SA.
 *
 * Copyright (C) 2010 Freescale Semiconductor, Inc.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/phy.h>
#include <linux/fec.h>

#include <asm/cacheflush.h>

#ifndef CONFIG_ARM
#include <asm/coldfire.h>
#include <asm/mcfsim.h>
#endif

#include "fec.h"

#if defined(CONFIG_ARM)
#define FEC_ALIGNMENT	0xf
#else
#define FEC_ALIGNMENT	0x3
#endif

#define DRIVER_NAME	"fec"

/* Controller is ENET-MAC */
#define FEC_QUIRK_ENET_MAC		(1 << 0)
/* Controller needs driver to swap frame */
#define FEC_QUIRK_SWAP_FRAME		(1 << 1)

static struct platform_device_id fec_devtype[] = {
	{
		.name = DRIVER_NAME,
		.driver_data = 0,
	}, {
		.name = "imx28-fec",
		.driver_data = FEC_QUIRK_ENET_MAC | FEC_QUIRK_SWAP_FRAME,
	}
};

static unsigned char macaddr[ETH_ALEN];
module_param_array(macaddr, byte, NULL, 0);
MODULE_PARM_DESC(macaddr, "FEC Ethernet MAC address");

#if defined(CONFIG_M5272)
/*
 * Some hardware gets it MAC address out of local flash memory.
 * if this is non-zero then assume it is the address to get MAC from.
 */
#if defined(CONFIG_NETtel)
#define	FEC_FLASHMAC	0xf0006006
#elif defined(CONFIG_GILBARCONAP) || defined(CONFIG_SCALES)
#define	FEC_FLASHMAC	0xf0006000
#elif defined(CONFIG_CANCam)
#define	FEC_FLASHMAC	0xf0020000
#elif defined (CONFIG_M5272C3)
#define	FEC_FLASHMAC	(0xffe04000 + 4)
#elif defined(CONFIG_MOD5272)
#define FEC_FLASHMAC 	0xffc0406b
#else
#define	FEC_FLASHMAC	0
#endif
#endif /* CONFIG_M5272 */

/* The number of Tx and Rx buffers.  These are allocated from the page
 * pool.  The code may assume these are power of two, so it it best
 * to keep them that size.
 * We don't need to allocate pages for the transmitter.  We just use
 * the skbuffer directly.
 */
#define FEC_ENET_RX_PAGES	8
#define FEC_ENET_RX_FRSIZE	2048
#define FEC_ENET_RX_FRPPG	(PAGE_SIZE / FEC_ENET_RX_FRSIZE)
#define RX_RING_SIZE		(FEC_ENET_RX_FRPPG * FEC_ENET_RX_PAGES)
#define FEC_ENET_TX_FRSIZE	2048
#define FEC_ENET_TX_FRPPG	(PAGE_SIZE / FEC_ENET_TX_FRSIZE)
#define TX_RING_SIZE		16	/* Must be power of two */
#define TX_RING_MOD_MASK	15	/*   for this to work */

#if (((RX_RING_SIZE + TX_RING_SIZE) * 8) > PAGE_SIZE)
#error "FEC: descriptor ring size constants too large"
#endif

/* Interrupt events/masks. */
#define FEC_ENET_HBERR	((uint)0x80000000)	/* Heartbeat error */
#define FEC_ENET_BABR	((uint)0x40000000)	/* Babbling receiver */
#define FEC_ENET_BABT	((uint)0x20000000)	/* Babbling transmitter */
#define FEC_ENET_GRA	((uint)0x10000000)	/* Graceful stop complete */
#define FEC_ENET_TXF	((uint)0x08000000)	/* Full frame transmitted */
#define FEC_ENET_TXB	((uint)0x04000000)	/* A buffer was transmitted */
#define FEC_ENET_RXF	((uint)0x02000000)	/* Full frame received */
#define FEC_ENET_RXB	((uint)0x01000000)	/* A buffer was received */
#define FEC_ENET_MII	((uint)0x00800000)	/* MII interrupt */
#define FEC_ENET_EBERR	((uint)0x00400000)	/* SDMA bus error */

#define FEC_DEFAULT_IMASK (FEC_ENET_TXF | FEC_ENET_RXF | FEC_ENET_MII)

/* The FEC stores dest/src/type, data, and checksum for receive packets.
 */
#define PKT_MAXBUF_SIZE		1518
#define PKT_MINBUF_SIZE		64
#define PKT_MAXBLR_SIZE		1520


/*
 * The 5270/5271/5280/5282/532x RX control register also contains maximum frame
 * size bits. Other FEC hardware does not, so we need to take that into
 * account when setting it.
 */
#if defined(CONFIG_M523x) || defined(CONFIG_M527x) || defined(CONFIG_M528x) || \
    defined(CONFIG_M520x) || defined(CONFIG_M532x) || defined(CONFIG_ARM)
#define	OPT_FRAME_SIZE	(PKT_MAXBUF_SIZE << 16)
#else
#define	OPT_FRAME_SIZE	0
#endif

/* The FEC buffer descriptors track the ring buffers.  The rx_bd_base and
 * tx_bd_base always point to the base of the buffer descriptors.  The
 * cur_rx and cur_tx point to the currently available buffer.
 * The dirty_tx tracks the current buffer that is being sent by the
 * controller.  The cur_tx and dirty_tx are equal under both completely
 * empty and completely full conditions.  The empty/ready indicator in
 * the buffer descriptor determines the actual condition.
 */
struct fec_enet_private {
	/* Hardware registers of the FEC device */
	void __iomem *hwp;

	struct net_device *netdev;

	struct clk *clk;

	/* The saved address of a sent-in-place packet/buffer, for skfree(). */
	unsigned char *tx_bounce[TX_RING_SIZE];
	struct	sk_buff* tx_skbuff[TX_RING_SIZE];
	struct	sk_buff* rx_skbuff[RX_RING_SIZE];
	ushort	skb_cur;
	ushort	skb_dirty;

	/* CPM dual port RAM relative addresses */
	dma_addr_t	bd_dma;
	/* Address of Rx and Tx buffers */
	struct bufdesc	*rx_bd_base;
	struct bufdesc	*tx_bd_base;
	/* The next free ring entry */
	struct bufdesc	*cur_rx, *cur_tx;
	/* The ring entries to be free()ed */
	struct bufdesc	*dirty_tx;

	uint	tx_full;
	/* hold while accessing the HW like ringbuffer for tx/rx but not MAC */
	spinlock_t hw_lock;

	struct	platform_device *pdev;

	int	opened;

	/* Phylib and MDIO interface */
	struct	mii_bus *mii_bus;
	struct	phy_device *phy_dev;
	int	mii_timeout;
	uint	phy_speed;
	phy_interface_t	phy_interface;
	int	link;
	int	full_duplex;
	struct	completion mdio_done;
};

/* FEC MII MMFR bits definition */
#define FEC_MMFR_ST		(1 << 30)
#define FEC_MMFR_OP_READ	(2 << 28)
#define FEC_MMFR_OP_WRITE	(1 << 28)
#define FEC_MMFR_PA(v)		((v & 0x1f) << 23)
#define FEC_MMFR_RA(v)		((v & 0x1f) << 18)
#define FEC_MMFR_TA		(2 << 16)
#define FEC_MMFR_DATA(v)	(v & 0xffff)

#define FEC_MII_TIMEOUT		1000 /* us */

/* Transmitter timeout */
#define TX_TIMEOUT (2 * HZ)

static void *swap_buffer(void *bufaddr, int len)
{
	int i;
	unsigned int *buf = bufaddr;

	for (i = 0; i < (len + 3) / 4; i++, buf++)
		*buf = cpu_to_be32(*buf);

	return bufaddr;
}

static netdev_tx_t
fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);
	const struct platform_device_id *id_entry =
				platform_get_device_id(fep->pdev);
	struct bufdesc *bdp;
	void *bufaddr;
	unsigned short	status;
	unsigned long flags;

	if (!fep->link) {
		/* Link is down or autonegotiation is in progress. */
		return NETDEV_TX_BUSY;
	}

	spin_lock_irqsave(&fep->hw_lock, flags);
	/* Fill in a Tx ring entry */
	bdp = fep->cur_tx;

	status = bdp->cbd_sc;

	if (status & BD_ENET_TX_READY) {
		/* Ooops.  All transmit buffers are full.  Bail out.
		 * This should not happen, since ndev->tbusy should be set.
		 */
		printk("%s: tx queue full!.\n", ndev->name);
		spin_unlock_irqrestore(&fep->hw_lock, flags);
		return NETDEV_TX_BUSY;
	}

	/* Clear all of the status flags */
	status &= ~BD_ENET_TX_STATS;

	/* Set buffer length and buffer pointer */
	bufaddr = skb->data;
	bdp->cbd_datlen = skb->len;

	/*
	 * On some FEC implementations data must be aligned on
	 * 4-byte boundaries. Use bounce buffers to copy data
	 * and get it aligned. Ugh.
	 */
	if (((unsigned long) bufaddr) & FEC_ALIGNMENT) {
		unsigned int index;
		index = bdp - fep->tx_bd_base;
		memcpy(fep->tx_bounce[index], skb->data, skb->len);
		bufaddr = fep->tx_bounce[index];
	}

	/*
	 * Some design made an incorrect assumption on endian mode of
	 * the system that it's running on. As the result, driver has to
	 * swap every frame going to and coming from the controller.
	 */
	if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
		swap_buffer(bufaddr, skb->len);

	/* Save skb pointer */
	fep->tx_skbuff[fep->skb_cur] = skb;

	ndev->stats.tx_bytes += skb->len;
	fep->skb_cur = (fep->skb_cur+1) & TX_RING_MOD_MASK;

	/* Push the data cache so the CPM does not get stale memory
	 * data.
	 */
	bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, bufaddr,
			FEC_ENET_TX_FRSIZE, DMA_TO_DEVICE);

	/* Send it on its way.  Tell FEC it's ready, interrupt when done,
	 * it's the last BD of the frame, and to put the CRC on the end.
	 */
	status |= (BD_ENET_TX_READY | BD_ENET_TX_INTR
			| BD_ENET_TX_LAST | BD_ENET_TX_TC);
	bdp->cbd_sc = status;

	/* Trigger transmission start */
	writel(0, fep->hwp + FEC_X_DES_ACTIVE);

	/* If this was the last BD in the ring, start at the beginning again. */
	if (status & BD_ENET_TX_WRAP)
		bdp = fep->tx_bd_base;
	else
		bdp++;

	if (bdp == fep->dirty_tx) {
		fep->tx_full = 1;
		netif_stop_queue(ndev);
	}

	fep->cur_tx = bdp;

	spin_unlock_irqrestore(&fep->hw_lock, flags);

	return NETDEV_TX_OK;
}

/* This function is called to start or restart the FEC during a link
 * change.  This only happens when switching between half and full
 * duplex.
 */
static void
fec_restart(struct net_device *ndev, int duplex)
{
	struct fec_enet_private *fep = netdev_priv(ndev);
	const struct platform_device_id *id_entry =
				platform_get_device_id(fep->pdev);
	int i;
	u32 val, temp_mac[2];

	/* Whack a reset.  We should wait for this. */
	writel(1, fep->hwp + FEC_ECNTRL);
	udelay(10);

	/*
	 * enet-mac reset will reset mac address registers too,
	 * so need to reconfigure it.
	 */
	if (id_entry->driver_data & FEC_QUIRK_ENET_MAC) {
		memcpy(&temp_mac, ndev->dev_addr, ETH_ALEN);
		writel(cpu_to_be32(temp_mac[0]), fep->hwp + FEC_ADDR_LOW);
		writel(cpu_to_be32(temp_mac[1]), fep->hwp + FEC_ADDR_HIGH);
	}

	/* Clear any outstanding interrupt. */
	writel(0xffc00000, fep->hwp + FEC_IEVENT);

	/* Reset all multicast.	*/
	writel(0, fep->hwp + FEC_GRP_HASH_TABLE_HIGH);
	writel(0, fep->hwp + FEC_GRP_HASH_TABLE_LOW);
#ifndef CONFIG_M5272
	writel(0, fep->hwp + FEC_HASH_TABLE_HIGH);
	writel(0, fep->hwp + FEC_HASH_TABLE_LOW);
#endif

	/* Set maximum receive buffer size. */
	writel(PKT_MAXBLR_SIZE, fep->hwp + FEC_R_BUFF_SIZE);

	/* Set receive and transmit descriptor base. */
	writel(fep->bd_dma, fep->hwp + FEC_R_DES_START);
	writel((unsigned long)fep->bd_dma + sizeof(struct bufdesc) * RX_RING_SIZE,
			fep->hwp + FEC_X_DES_START);

	fep->dirty_tx = fep->cur_tx = fep->tx_bd_base;
	fep->cur_rx = fep->rx_bd_base;

	/* Reset SKB transmit buffers. */
	fep->skb_cur = fep->skb_dirty = 0;
	for (i = 0; i <= TX_RING_MOD_MASK; i++) {
		if (fep->tx_skbuff[i]) {
			dev_kfree_skb_any(fep->tx_skbuff[i]);
			fep->tx_skbuff[i] = NULL;
		}
	}

	/* Enable MII mode */
	if (duplex) {
		/* MII enable / FD enable */
		writel(OPT_FRAME_SIZE | 0x04, fep->hwp + FEC_R_CNTRL);
		writel(0x04, fep->hwp + FEC_X_CNTRL);
	} else {
		/* MII enable / No Rcv on Xmit */
		writel(OPT_FRAME_SIZE | 0x06, fep->hwp + FEC_R_CNTRL);
		writel(0x0, fep->hwp + FEC_X_CNTRL);
	}
	fep->full_duplex = duplex;

	/* Set MII speed */
	writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);

	/*
	 * The phy interface and speed need to get configured
	 * differently on enet-mac.
	 */
	if (id_entry->driver_data & FEC_QUIRK_ENET_MAC) {
		val = readl(fep->hwp + FEC_R_CNTRL);

		/* MII or RMII */
		if (fep->phy_interface == PHY_INTERFACE_MODE_RMII)
			val |= (1 << 8);
		else
			val &= ~(1 << 8);

		/* 10M or 100M */
		if (fep->phy_dev && fep->phy_dev->speed == SPEED_100)
			val &= ~(1 << 9);
		else
			val |= (1 << 9);

		writel(val, fep->hwp + FEC_R_CNTRL);
	} else {
#ifdef FEC_MIIGSK_ENR
		if (fep->phy_interface == PHY_INTERFACE_MODE_RMII) {
			/* disable the gasket and wait */
			writel(0, fep->hwp + FEC_MIIGSK_ENR);
			while (readl(fep->hwp + FEC_MIIGSK_ENR) & 4)
				udelay(1);

			/*
			 * configure the gasket:
			 *   RMII, 50 MHz, no loopback, no echo
			 */
			writel(1, fep->hwp + FEC_MIIGSK_CFGR);

			/* re-enable the gasket */
			writel(2, fep->hwp + FEC_MIIGSK_ENR);
		}
#endif
	}

	/* And last, enable the transmit and receive processing */
	writel(2, fep->hwp + FEC_ECNTRL);
	writel(0, fep->hwp + FEC_R_DES_ACTIVE);

	/* Enable interrupts we wish to service */
	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
}

static void
fec_stop(struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);

	/* We cannot expect a graceful transmit stop without link !!! */
	if (fep->link) {
		writel(1, fep->hwp + FEC_X_CNTRL); /* Graceful transmit stop */
		udelay(10);
		if (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_GRA))
			printk("fec_stop : Graceful transmit stop did not complete !\n");
	}

	/* Whack a reset.  We should wait for this. */
	writel(1, fep->hwp + FEC_ECNTRL);
	udelay(10);
	writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
	writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
}


static void
fec_timeout(struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);

	ndev->stats.tx_errors++;

	fec_restart(ndev, fep->full_duplex);
	netif_wake_queue(ndev);
}

static void
fec_enet_tx(struct net_device *ndev)
{
	struct	fec_enet_private *fep;
	struct bufdesc *bdp;
	unsigned short status;
	struct	sk_buff	*skb;

	fep = netdev_priv(ndev);
	spin_lock(&fep->hw_lock);
	bdp = fep->dirty_tx;

	while (((status = bdp->cbd_sc) & BD_ENET_TX_READY) == 0) {
		if (bdp == fep->cur_tx && fep->tx_full == 0)
			break;

		dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
				FEC_ENET_TX_FRSIZE, DMA_TO_DEVICE);
		bdp->cbd_bufaddr = 0;

		skb = fep->tx_skbuff[fep->skb_dirty];
		/* Check for errors. */
		if (status & (BD_ENET_TX_HB | BD_ENET_TX_LC |
				   BD_ENET_TX_RL | BD_ENET_TX_UN |
				   BD_ENET_TX_CSL)) {
			ndev->stats.tx_errors++;
			if (status & BD_ENET_TX_HB)  /* No heartbeat */
				ndev->stats.tx_heartbeat_errors++;
			if (status & BD_ENET_TX_LC)  /* Late collision */
				ndev->stats.tx_window_errors++;
			if (status & BD_ENET_TX_RL)  /* Retrans limit */
				ndev->stats.tx_aborted_errors++;
			if (status & BD_ENET_TX_UN)  /* Underrun */
				ndev->stats.tx_fifo_errors++;
			if (status & BD_ENET_TX_CSL) /* Carrier lost */
				ndev->stats.tx_carrier_errors++;
		} else {
			ndev->stats.tx_packets++;
		}

		if (status & BD_ENET_TX_READY)
			printk("HEY! Enet xmit interrupt and TX_READY.\n");

		/* Deferred means some collisions occurred during transmit,
		 * but we eventually sent the packet OK.
		 */
		if (status & BD_ENET_TX_DEF)
			ndev->stats.collisions++;

		/* Free the sk buffer associated with this last transmit */
		dev_kfree_skb_any(skb);
		fep->tx_skbuff[fep->skb_dirty] = NULL;
		fep->skb_dirty = (fep->skb_dirty + 1) & TX_RING_MOD_MASK;

		/* Update pointer to next buffer descriptor to be transmitted */
		if (status & BD_ENET_TX_WRAP)
			bdp = fep->tx_bd_base;
		else
			bdp++;

		/* Since we have freed up a buffer, the ring is no longer full
		 */
		if (fep->tx_full) {
			fep->tx_full = 0;
			if (netif_queue_stopped(ndev))
				netif_wake_queue(ndev);
		}
	}
	fep->dirty_tx = bdp;
	spin_unlock(&fep->hw_lock);
}


/* During a receive, the cur_rx points to the current incoming buffer.
 * When we update through the ring, if the next incoming buffer has
 * not been given to the system, we just set the empty indicator,
 * effectively tossing the packet.
 */
static void
fec_enet_rx(struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);
	const struct platform_device_id *id_entry =
				platform_get_device_id(fep->pdev);
	struct bufdesc *bdp;
	unsigned short status;
	struct	sk_buff	*skb;
	ushort	pkt_len;
	__u8 *data;

#ifdef CONFIG_M532x
	flush_cache_all();
#endif

	spin_lock(&fep->hw_lock);

	/* First, grab all of the stats for the incoming packet.
	 * These get messed up if we get called due to a busy condition.
	 */
	bdp = fep->cur_rx;

	while (!((status = bdp->cbd_sc) & BD_ENET_RX_EMPTY)) {

		/* Since we have allocated space to hold a complete frame,
		 * the last indicator should be set.
		 */
		if ((status & BD_ENET_RX_LAST) == 0)
			printk("FEC ENET: rcv is not +last\n");

		if (!fep->opened)
			goto rx_processing_done;

		/* Check for errors. */
		if (status & (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
			   BD_ENET_RX_CR | BD_ENET_RX_OV)) {
			ndev->stats.rx_errors++;
			if (status & (BD_ENET_RX_LG | BD_ENET_RX_SH)) {
				/* Frame too long or too short. */
				ndev->stats.rx_length_errors++;
			}
			if (status & BD_ENET_RX_NO)	/* Frame alignment */
				ndev->stats.rx_frame_errors++;
			if (status & BD_ENET_RX_CR)	/* CRC Error */
				ndev->stats.rx_crc_errors++;
			if (status & BD_ENET_RX_OV)	/* FIFO overrun */
				ndev->stats.rx_fifo_errors++;
		}

		/* Report late collisions as a frame error.
		 * On this error, the BD is closed, but we don't know what we
		 * have in the buffer.  So, just drop this frame on the floor.
		 */
		if (status & BD_ENET_RX_CL) {
			ndev->stats.rx_errors++;
			ndev->stats.rx_frame_errors++;
			goto rx_processing_done;
		}

		/* Process the incoming frame. */
		ndev->stats.rx_packets++;
		pkt_len = bdp->cbd_datlen;
		ndev->stats.rx_bytes += pkt_len;
		data = (__u8*)__va(bdp->cbd_bufaddr);

		dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr,
				FEC_ENET_TX_FRSIZE, DMA_FROM_DEVICE);

		if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME)
			swap_buffer(data, pkt_len);

		/* This does 16 byte alignment, exactly what we need.
		 * The packet length includes FCS, but we don't want to
		 * include that when passing upstream as it messes up
		 * bridging applications.
		 */
		skb = dev_alloc_skb(pkt_len - 4 + NET_IP_ALIGN);

		if (unlikely(!skb)) {
			printk("%s: Memory squeeze, dropping packet.\n",
					ndev->name);
			ndev->stats.rx_dropped++;
		} else {
			skb_reserve(skb, NET_IP_ALIGN);
			skb_put(skb, pkt_len - 4);	/* Make room */
			skb_copy_to_linear_data(skb, data, pkt_len - 4);
			skb->protocol = eth_type_trans(skb, ndev);
			netif_rx(skb);
		}

		bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, data,
				FEC_ENET_TX_FRSIZE, DMA_FROM_DEVICE);
rx_processing_done:
		/* Clear the status flags for this buffer */
		status &= ~BD_ENET_RX_STATS;

		/* Mark the buffer empty */
		status |= BD_ENET_RX_EMPTY;
		bdp->cbd_sc = status;

		/* Update BD pointer to next entry */
		if (status & BD_ENET_RX_WRAP)
			bdp = fep->rx_bd_base;
		else
			bdp++;
		/* Doing this here will keep the FEC running while we process
		 * incoming frames.  On a heavily loaded network, we should be
		 * able to keep up at the expense of system resources.
		 */
		writel(0, fep->hwp + FEC_R_DES_ACTIVE);
	}
	fep->cur_rx = bdp;

	spin_unlock(&fep->hw_lock);
}

static irqreturn_t
fec_enet_interrupt(int irq, void *dev_id)
{
	struct net_device *ndev = dev_id;
	struct fec_enet_private *fep = netdev_priv(ndev);
	uint int_events;
	irqreturn_t ret = IRQ_NONE;

	do {
		int_events = readl(fep->hwp + FEC_IEVENT);
		writel(int_events, fep->hwp + FEC_IEVENT);

		if (int_events & FEC_ENET_RXF) {
			ret = IRQ_HANDLED;
			fec_enet_rx(ndev);
		}

		/* Transmit OK, or non-fatal error. Update the buffer
		 * descriptors. FEC handles all errors, we just discover
		 * them as part of the transmit process.
		 */
		if (int_events & FEC_ENET_TXF) {
			ret = IRQ_HANDLED;
			fec_enet_tx(ndev);
		}

		if (int_events & FEC_ENET_MII) {
			ret = IRQ_HANDLED;
			complete(&fep->mdio_done);
		}
	} while (int_events);

	return ret;
}



/* ------------------------------------------------------------------------- */
static void __inline__ fec_get_mac(struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);
	struct fec_platform_data *pdata = fep->pdev->dev.platform_data;
	unsigned char *iap, tmpaddr[ETH_ALEN];

	/*
	 * try to get mac address in following order:
	 *
	 * 1) module parameter via kernel command line in form
	 *    fec.macaddr=0x00,0x04,0x9f,0x01,0x30,0xe0
	 */
	iap = macaddr;

	/*
	 * 2) from flash or fuse (via platform data)
	 */
	if (!is_valid_ether_addr(iap)) {
#ifdef CONFIG_M5272
		if (FEC_FLASHMAC)
			iap = (unsigned char *)FEC_FLASHMAC;
#else
		if (pdata)
			memcpy(iap, pdata->mac, ETH_ALEN);
#endif
	}

	/*
	 * 3) FEC mac registers set by bootloader
	 */
	if (!is_valid_ether_addr(iap)) {
		*((unsigned long *) &tmpaddr[0]) =
			be32_to_cpu(readl(fep->hwp + FEC_ADDR_LOW));
		*((unsigned short *) &tmpaddr[4]) =
			be16_to_cpu(readl(fep->hwp + FEC_ADDR_HIGH) >> 16);
		iap = &tmpaddr[0];
	}

	memcpy(ndev->dev_addr, iap, ETH_ALEN);

	/* Adjust MAC if using macaddr */
	if (iap == macaddr)
		 ndev->dev_addr[ETH_ALEN-1] = macaddr[ETH_ALEN-1] + fep->pdev->id;
}

/* ------------------------------------------------------------------------- */

/*
 * Phy section
 */
static void fec_enet_adjust_link(struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);
	struct phy_device *phy_dev = fep->phy_dev;
	unsigned long flags;

	int status_change = 0;

	spin_lock_irqsave(&fep->hw_lock, flags);

	/* Prevent a state halted on mii error */
	if (fep->mii_timeout && phy_dev->state == PHY_HALTED) {
		phy_dev->state = PHY_RESUMING;
		goto spin_unlock;
	}

	/* Duplex link change */
	if (phy_dev->link) {
		if (fep->full_duplex != phy_dev->duplex) {
			fec_restart(ndev, phy_dev->duplex);
			status_change = 1;
		}
	}

	/* Link on or off change */
	if (phy_dev->link != fep->link) {
		fep->link = phy_dev->link;
		if (phy_dev->link)
			fec_restart(ndev, phy_dev->duplex);
		else
			fec_stop(ndev);
		status_change = 1;
	}

spin_unlock:
	spin_unlock_irqrestore(&fep->hw_lock, flags);

	if (status_change)
		phy_print_status(phy_dev);
}

static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
	struct fec_enet_private *fep = bus->priv;
	unsigned long time_left;

	fep->mii_timeout = 0;
	init_completion(&fep->mdio_done);

	/* start a read op */
	writel(FEC_MMFR_ST | FEC_MMFR_OP_READ |
		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) |
		FEC_MMFR_TA, fep->hwp + FEC_MII_DATA);

	/* wait for end of transfer */
	time_left = wait_for_completion_timeout(&fep->mdio_done,
			usecs_to_jiffies(FEC_MII_TIMEOUT));
	if (time_left == 0) {
		fep->mii_timeout = 1;
		printk(KERN_ERR "FEC: MDIO read timeout\n");
		return -ETIMEDOUT;
	}

	/* return value */
	return FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA));
}

static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
			   u16 value)
{
	struct fec_enet_private *fep = bus->priv;
	unsigned long time_left;

	fep->mii_timeout = 0;
	init_completion(&fep->mdio_done);

	/* start a write op */
	writel(FEC_MMFR_ST | FEC_MMFR_OP_WRITE |
		FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(regnum) |
		FEC_MMFR_TA | FEC_MMFR_DATA(value),
		fep->hwp + FEC_MII_DATA);

	/* wait for end of transfer */
	time_left = wait_for_completion_timeout(&fep->mdio_done,
			usecs_to_jiffies(FEC_MII_TIMEOUT));
	if (time_left == 0) {
		fep->mii_timeout = 1;
		printk(KERN_ERR "FEC: MDIO write timeout\n");
		return -ETIMEDOUT;
	}

	return 0;
}

static int fec_enet_mdio_reset(struct mii_bus *bus)
{
	return 0;
}

static int fec_enet_mii_probe(struct net_device *ndev)
{
	struct fec_enet_private *fep = netdev_priv(ndev);
	struct phy_device *phy_dev = NULL;
	char mdio_bus_id[MII_BUS_ID_SIZE];
	char phy_name[MII_BUS_ID_SIZE + 3];
	int phy_id;
	int dev_id = fep->pdev->id;

	fep->phy_dev = NULL;

	/* check for attached phy */
	for (phy_id = 0; (phy_id < PHY_MAX_ADDR); phy_id++) {
		if ((fep->mii_bus->phy_mask & (1 << phy_id)))
			continue;
		if (fep->mii_bus->phy_map[phy_id] == NULL)
			continue;
		if (fep->mii_bus->phy_map[phy_id]->phy_id == 0)
			continue;
		if (dev_id--)
			continue;
		strncpy(mdio_bus_id, fep->mii_bus->id, MII_BUS_ID_SIZE);
		break;
	}

	if (phy_id >= PHY_MAX_ADDR) {
		printk(KERN_INFO "%s: no PHY, assuming direct connection "
			"to switch\n", ndev->name);
		strncpy(mdio_bus_id, "0", MII_BUS_ID_SIZE);
		phy_id = 0;
	}

	snprintf(phy_name, MII_BUS_ID_SIZE, PHY_ID_FMT, mdio_bus_id, phy_id);
	phy_dev = phy_connect(ndev, phy_name, &fec_enet_adjust_link, 0,
		PHY_INTERFACE_MODE_MII);
	if (IS_ERR(phy_dev)) {
		printk(KERN_ERR "%s: could not attach to PHY\n", ndev->name);
		return PTR_ERR(phy_dev);
	}

	/* mask with MAC supported features */
	phy_dev->supported &= PHY_BASIC_FEATURES;
	phy_dev->advertising = phy_dev->supported;

	fep->phy_dev = phy_dev;
	fep->link = 0;
	fep->full_duplex = 0;

	printk(KERN_INFO "%s: Freescale FEC PHY driver [%s] "
		"(mii_bus:phy_addr=%s, irq=%d)\n", ndev->name,
		fep->phy_dev->drv->name, dev_name(&fep->phy_dev->dev),
		fep->phy_dev->irq);

	return 0;
}

static int fec_enet_mii_init(struct platform_device *pdev)
{
	static struct mii_bus *fec0_mii_bus;
	struct net_device *ndev = platform_get_drvdata(pdev);
	struct fec_enet_private *fep = netdev_priv(ndev);
	const struct platform_device_id *id_entry =
				platform_get_device_id(fep->pdev);
	int err = -ENXIO, i;

	/*
	 * The dual fec interfaces are not equivalent with enet-mac.
	 * Here are the differences:
	 *
	 *  - fec0 supports MII & RMII modes while fec1 only supports RMII
	 *  - fec0 acts as the 1588 time master while fec1 is slave
	 *  - external phys can only be configured by fec0
	 *
	 * That is to say fec1 can not work independently. It only works
	 * when fec0 is working. The reason behind this design is that the
	 * second interface is added primarily for Switch mode.
	 *
	 * Because of the last point above, both phys are attached on fec0
	 * mdio interface in board design, and need to be configured by
	 * fec0 mii_bus.
	 */
	if ((id_entry->driver_data & FEC_QUIRK_ENET_MAC) && pdev->id) {
		/* fec1 uses fec0 mii_bus */
		fep->mii_bus = fec0_mii_bus;
		return 0;
	}

	fep->mii_timeout = 0;

	/*
	 * Set MII speed to 2.5 MHz (= clk_get_rate() / 2 * phy_speed)
	 */
	fep->phy_speed = DIV_ROUND_UP(clk_get_rate(fep->clk), 5000000) << 1;
	writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);

	fep->mii_bus = mdiobus_alloc();
	if (fep->mii_bus == NULL) {
		err = -ENOMEM;
		goto err_out;
	}

	fep->mii_bus->name = "fec_enet_mii_bus";
	fep->mii_bus->read = fec_enet_mdio_read;
	fep->mii_bus->write = fec_enet_mdio_write;
	fep->mii_bus->reset = fec_enet_mdio_reset;
	snprintf(fep->mii_bus->id, MII_BUS_ID_SIZE, "%x", pdev->id + 1);
	fep->mii_bus->priv = fep;
	fep->mii_bus->parent = &pdev->dev;

	fep->mii_bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
	if (!fep->mii_bus->irq) {
		err = -ENOMEM;
		goto err_out_free_mdiobus;
	}

	for (i = 0; i < PHY_MAX_ADDR; i++)
		fep->mii_bus->irq[i] = PHY_POLL;

	platform_set_drvdata(ndev, fep->mii_bus);

	if (mdiobus_register(fep->mii_bus))
		goto err_out_free_mdio_irq;

	/* save fec0 mii_bus */
	if (id_entry->driver_data & FEC_QUIRK_ENET_MAC)
		fec0_mii_bus = fep->mii_bus;

	return 0;

err_out_free_mdio_irq:
	kfree(fep->mii_bus->irq);
err_out_free_mdiobus:
	mdiobus_free(fep->mii_bus);
err_out:
	return err;