/*
 *  Driver for the IDT RC32434 (Korina) on-chip ethernet controller.
 *
 *  Copyright 2004 IDT Inc. (rischelp@idt.com)
 *  Copyright 2006 Felix Fietkau <nbd@openwrt.org>
 *  Copyright 2008 Florian Fainelli <florian@openwrt.org>
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
 *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
 *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
 *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *  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.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  Writing to a DMA status register:
 *
 *  When writing to the status register, you should mask the bit you have
 *  been testing the status register with. Both Tx and Rx DMA registers
 *  should stick to this procedure.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/crc32.h>

#include <asm/bootinfo.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/pgtable.h>
#include <asm/segment.h>
#include <asm/io.h>
#include <asm/dma.h>

#include <asm/mach-rc32434/rb.h>
#include <asm/mach-rc32434/rc32434.h>
#include <asm/mach-rc32434/eth.h>
#include <asm/mach-rc32434/dma_v.h>

#define DRV_NAME        "korina"
#define DRV_VERSION     "0.10"
#define DRV_RELDATE     "04Mar2008"

#define STATION_ADDRESS_HIGH(dev) (((dev)->dev_addr[0] << 8) | \
				   ((dev)->dev_addr[1]))
#define STATION_ADDRESS_LOW(dev)  (((dev)->dev_addr[2] << 24) | \
				   ((dev)->dev_addr[3] << 16) | \
				   ((dev)->dev_addr[4] << 8)  | \
				   ((dev)->dev_addr[5]))

#define MII_CLOCK 1250000 	/* no more than 2.5MHz */

/* the following must be powers of two */
#define KORINA_NUM_RDS	64  /* number of receive descriptors */
#define KORINA_NUM_TDS	64  /* number of transmit descriptors */

/* KORINA_RBSIZE is the hardware's default maximum receive
 * frame size in bytes. Having this hardcoded means that there
 * is no support for MTU sizes greater than 1500. */
#define KORINA_RBSIZE	1536 /* size of one resource buffer = Ether MTU */
#define KORINA_RDS_MASK	(KORINA_NUM_RDS - 1)
#define KORINA_TDS_MASK	(KORINA_NUM_TDS - 1)
#define RD_RING_SIZE 	(KORINA_NUM_RDS * sizeof(struct dma_desc))
#define TD_RING_SIZE	(KORINA_NUM_TDS * sizeof(struct dma_desc))

#define TX_TIMEOUT 	(6000 * HZ / 1000)

enum chain_status { desc_filled, desc_empty };
#define IS_DMA_FINISHED(X)   (((X) & (DMA_DESC_FINI)) != 0)
#define IS_DMA_DONE(X)   (((X) & (DMA_DESC_DONE)) != 0)
#define RCVPKT_LENGTH(X)     (((X) & ETH_RX_LEN) >> ETH_RX_LEN_BIT)

/* Information that need to be kept for each board. */
struct korina_private {
	struct eth_regs *eth_regs;
	struct dma_reg *rx_dma_regs;
	struct dma_reg *tx_dma_regs;
	struct dma_desc *td_ring; /* transmit descriptor ring */
	struct dma_desc *rd_ring; /* receive descriptor ring  */

	struct sk_buff *tx_skb[KORINA_NUM_TDS];
	struct sk_buff *rx_skb[KORINA_NUM_RDS];

	int rx_next_done;
	int rx_chain_head;
	int rx_chain_tail;
	enum chain_status rx_chain_status;

	int tx_next_done;
	int tx_chain_head;
	int tx_chain_tail;
	enum chain_status tx_chain_status;
	int tx_count;
	int tx_full;

	int rx_irq;
	int tx_irq;
	int ovr_irq;
	int und_irq;

	spinlock_t lock;        /* NIC xmit lock */

	int dma_halt_cnt;
	int dma_run_cnt;
	struct napi_struct napi;
	struct timer_list media_check_timer;
	struct mii_if_info mii_if;
	struct net_device *dev;
	int phy_addr;
};

extern unsigned int idt_cpu_freq;

static inline void korina_start_dma(struct dma_reg *ch, u32 dma_addr)
{
	writel(0, &ch->dmandptr);
	writel(dma_addr, &ch->dmadptr);
}

static inline void korina_abort_dma(struct net_device *dev,
					struct dma_reg *ch)
{
       if (readl(&ch->dmac) & DMA_CHAN_RUN_BIT) {
	       writel(0x10, &ch->dmac);

	       while (!(readl(&ch->dmas) & DMA_STAT_HALT))
		       dev->trans_start = jiffies;

	       writel(0, &ch->dmas);
       }

       writel(0, &ch->dmadptr);
       writel(0, &ch->dmandptr);
}

static inline void korina_chain_dma(struct dma_reg *ch, u32 dma_addr)
{
	writel(dma_addr, &ch->dmandptr);
}

static void korina_abort_tx(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);

	korina_abort_dma(dev, lp->tx_dma_regs);
}

static void korina_abort_rx(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);

	korina_abort_dma(dev, lp->rx_dma_regs);
}

static void korina_start_rx(struct korina_private *lp,
					struct dma_desc *rd)
{
	korina_start_dma(lp->rx_dma_regs, CPHYSADDR(rd));
}

static void korina_chain_rx(struct korina_private *lp,
					struct dma_desc *rd)
{
	korina_chain_dma(lp->rx_dma_regs, CPHYSADDR(rd));
}

/* transmit packet */
static int korina_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	unsigned long flags;
	u32 length;
	u32 chain_prev, chain_next;
	struct dma_desc *td;

	spin_lock_irqsave(&lp->lock, flags);

	td = &lp->td_ring[lp->tx_chain_tail];

	/* stop queue when full, drop pkts if queue already full */
	if (lp->tx_count >= (KORINA_NUM_TDS - 2)) {
		lp->tx_full = 1;

		if (lp->tx_count == (KORINA_NUM_TDS - 2))
			netif_stop_queue(dev);
		else {
			dev->stats.tx_dropped++;
			dev_kfree_skb_any(skb);
			spin_unlock_irqrestore(&lp->lock, flags);

			return NETDEV_TX_BUSY;
		}
	}

	lp->tx_count++;

	lp->tx_skb[lp->tx_chain_tail] = skb;

	length = skb->len;
	dma_cache_wback((u32)skb->data, skb->len);

	/* Setup the transmit descriptor. */
	dma_cache_inv((u32) td, sizeof(*td));
	td->ca = CPHYSADDR(skb->data);
	chain_prev = (lp->tx_chain_tail - 1) & KORINA_TDS_MASK;
	chain_next = (lp->tx_chain_tail + 1) & KORINA_TDS_MASK;

	if (readl(&(lp->tx_dma_regs->dmandptr)) == 0) {
		if (lp->tx_chain_status == desc_empty) {
			/* Update tail */
			td->control = DMA_COUNT(length) |
					DMA_DESC_COF | DMA_DESC_IOF;
			/* Move tail */
			lp->tx_chain_tail = chain_next;
			/* Write to NDPTR */
			writel(CPHYSADDR(&lp->td_ring[lp->tx_chain_head]),
					&lp->tx_dma_regs->dmandptr);
			/* Move head to tail */
			lp->tx_chain_head = lp->tx_chain_tail;
		} else {
			/* Update tail */
			td->control = DMA_COUNT(length) |
					DMA_DESC_COF | DMA_DESC_IOF;
			/* Link to prev */
			lp->td_ring[chain_prev].control &=
					~DMA_DESC_COF;
			/* Link to prev */
			lp->td_ring[chain_prev].link =  CPHYSADDR(td);
			/* Move tail */
			lp->tx_chain_tail = chain_next;
			/* Write to NDPTR */
			writel(CPHYSADDR(&lp->td_ring[lp->tx_chain_head]),
					&(lp->tx_dma_regs->dmandptr));
			/* Move head to tail */
			lp->tx_chain_head = lp->tx_chain_tail;
			lp->tx_chain_status = desc_empty;
		}
	} else {
		if (lp->tx_chain_status == desc_empty) {
			/* Update tail */
			td->control = DMA_COUNT(length) |
					DMA_DESC_COF | DMA_DESC_IOF;
			/* Move tail */
			lp->tx_chain_tail = chain_next;
			lp->tx_chain_status = desc_filled;
		} else {
			/* Update tail */
			td->control = DMA_COUNT(length) |
					DMA_DESC_COF | DMA_DESC_IOF;
			lp->td_ring[chain_prev].control &=
					~DMA_DESC_COF;
			lp->td_ring[chain_prev].link =  CPHYSADDR(td);
			lp->tx_chain_tail = chain_next;
		}
	}
	dma_cache_wback((u32) td, sizeof(*td));

	dev->trans_start = jiffies;
	spin_unlock_irqrestore(&lp->lock, flags);

	return NETDEV_TX_OK;
}

static int mdio_read(struct net_device *dev, int mii_id, int reg)
{
	struct korina_private *lp = netdev_priv(dev);
	int ret;

	mii_id = ((lp->rx_irq == 0x2c ? 1 : 0) << 8);

	writel(0, &lp->eth_regs->miimcfg);
	writel(0, &lp->eth_regs->miimcmd);
	writel(mii_id | reg, &lp->eth_regs->miimaddr);
	writel(ETH_MII_CMD_SCN, &lp->eth_regs->miimcmd);

	ret = (int)(readl(&lp->eth_regs->miimrdd));
	return ret;
}

static void mdio_write(struct net_device *dev, int mii_id, int reg, int val)
{
	struct korina_private *lp = netdev_priv(dev);

	mii_id = ((lp->rx_irq == 0x2c ? 1 : 0) << 8);

	writel(0, &lp->eth_regs->miimcfg);
	writel(1, &lp->eth_regs->miimcmd);
	writel(mii_id | reg, &lp->eth_regs->miimaddr);
	writel(ETH_MII_CMD_SCN, &lp->eth_regs->miimcmd);
	writel(val, &lp->eth_regs->miimwtd);
}

/* Ethernet Rx DMA interrupt */
static irqreturn_t korina_rx_dma_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct korina_private *lp = netdev_priv(dev);
	u32 dmas, dmasm;
	irqreturn_t retval;

	dmas = readl(&lp->rx_dma_regs->dmas);
	if (dmas & (DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR)) {
		dmasm = readl(&lp->rx_dma_regs->dmasm);
		writel(dmasm | (DMA_STAT_DONE |
				DMA_STAT_HALT | DMA_STAT_ERR),
				&lp->rx_dma_regs->dmasm);

		napi_schedule(&lp->napi);

		if (dmas & DMA_STAT_ERR)
			printk(KERN_ERR "%s: DMA error\n", dev->name);

		retval = IRQ_HANDLED;
	} else
		retval = IRQ_NONE;

	return retval;
}

static int korina_rx(struct net_device *dev, int limit)
{
	struct korina_private *lp = netdev_priv(dev);
	struct dma_desc *rd = &lp->rd_ring[lp->rx_next_done];
	struct sk_buff *skb, *skb_new;
	u8 *pkt_buf;
	u32 devcs, pkt_len, dmas;
	int count;

	dma_cache_inv((u32)rd, sizeof(*rd));

	for (count = 0; count < limit; count++) {
		skb = lp->rx_skb[lp->rx_next_done];
		skb_new = NULL;

		devcs = rd->devcs;

		if ((KORINA_RBSIZE - (u32)DMA_COUNT(rd->control)) == 0)
			break;

		/* Update statistics counters */
		if (devcs & ETH_RX_CRC)
			dev->stats.rx_crc_errors++;
		if (devcs & ETH_RX_LOR)
			dev->stats.rx_length_errors++;
		if (devcs & ETH_RX_LE)
			dev->stats.rx_length_errors++;
		if (devcs & ETH_RX_OVR)
			dev->stats.rx_over_errors++;
		if (devcs & ETH_RX_CV)
			dev->stats.rx_frame_errors++;
		if (devcs & ETH_RX_CES)
			dev->stats.rx_length_errors++;
		if (devcs & ETH_RX_MP)
			dev->stats.multicast++;

		if ((devcs & ETH_RX_LD) != ETH_RX_LD) {
			/* check that this is a whole packet
			 * WARNING: DMA_FD bit incorrectly set
			 * in Rc32434 (errata ref #077) */
			dev->stats.rx_errors++;
			dev->stats.rx_dropped++;
		} else if ((devcs & ETH_RX_ROK)) {
			pkt_len = RCVPKT_LENGTH(devcs);

			/* must be the (first and) last
			 * descriptor then */
			pkt_buf = (u8 *)lp->rx_skb[lp->rx_next_done]->data;

			/* invalidate the cache */
			dma_cache_inv((unsigned long)pkt_buf, pkt_len - 4);

			/* Malloc up new buffer. */
			skb_new = netdev_alloc_skb(dev, KORINA_RBSIZE + 2);

			if (!skb_new)
				break;
			/* Do not count the CRC */
			skb_put(skb, pkt_len - 4);
			skb->protocol = eth_type_trans(skb, dev);

			/* Pass the packet to upper layers */
			netif_receive_skb(skb);
			dev->stats.rx_packets++;
			dev->stats.rx_bytes += pkt_len;

			/* Update the mcast stats */
			if (devcs & ETH_RX_MP)
				dev->stats.multicast++;

			/* 16 bit align */
			skb_reserve(skb_new, 2);

			lp->rx_skb[lp->rx_next_done] = skb_new;
		}

		rd->devcs = 0;

		/* Restore descriptor's curr_addr */
		if (skb_new)
			rd->ca = CPHYSADDR(skb_new->data);
		else
			rd->ca = CPHYSADDR(skb->data);

		rd->control = DMA_COUNT(KORINA_RBSIZE) |
			DMA_DESC_COD | DMA_DESC_IOD;
		lp->rd_ring[(lp->rx_next_done - 1) &
			KORINA_RDS_MASK].control &=
			~DMA_DESC_COD;

		lp->rx_next_done = (lp->rx_next_done + 1) & KORINA_RDS_MASK;
		dma_cache_wback((u32)rd, sizeof(*rd));
		rd = &lp->rd_ring[lp->rx_next_done];
		writel(~DMA_STAT_DONE, &lp->rx_dma_regs->dmas);
	}

	dmas = readl(&lp->rx_dma_regs->dmas);

	if (dmas & DMA_STAT_HALT) {
		writel(~(DMA_STAT_HALT | DMA_STAT_ERR),
				&lp->rx_dma_regs->dmas);

		lp->dma_halt_cnt++;
		rd->devcs = 0;
		skb = lp->rx_skb[lp->rx_next_done];
		rd->ca = CPHYSADDR(skb->data);
		dma_cache_wback((u32)rd, sizeof(*rd));
		korina_chain_rx(lp, rd);
	}

	return count;
}

static int korina_poll(struct napi_struct *napi, int budget)
{
	struct korina_private *lp =
		container_of(napi, struct korina_private, napi);
	struct net_device *dev = lp->dev;
	int work_done;

	work_done = korina_rx(dev, budget);
	if (work_done < budget) {
		napi_complete(napi);

		writel(readl(&lp->rx_dma_regs->dmasm) &
			~(DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR),
			&lp->rx_dma_regs->dmasm);
	}
	return work_done;
}

/*
 * Set or clear the multicast filter for this adaptor.
 */
static void korina_multicast_list(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	unsigned long flags;
	struct dev_mc_list *dmi = dev->mc_list;
	u32 recognise = ETH_ARC_AB;	/* always accept broadcasts */
	int i;

	/* Set promiscuous mode */
	if (dev->flags & IFF_PROMISC)
		recognise |= ETH_ARC_PRO;

	else if ((dev->flags & IFF_ALLMULTI) || (dev->mc_count > 4))
		/* All multicast and broadcast */
		recognise |= ETH_ARC_AM;

	/* Build the hash table */
	if (dev->mc_count > 4) {
		u16 hash_table[4];
		u32 crc;

		for (i = 0; i < 4; i++)
			hash_table[i] = 0;

		for (i = 0; i < dev->mc_count; i++) {
			char *addrs = dmi->dmi_addr;

			dmi = dmi->next;

			if (!(*addrs & 1))
				continue;

			crc = ether_crc_le(6, addrs);
			crc >>= 26;
			hash_table[crc >> 4] |= 1 << (15 - (crc & 0xf));
		}
		/* Accept filtered multicast */
		recognise |= ETH_ARC_AFM;

		/* Fill the MAC hash tables with their values */
		writel((u32)(hash_table[1] << 16 | hash_table[0]),
					&lp->eth_regs->ethhash0);
		writel((u32)(hash_table[3] << 16 | hash_table[2]),
					&lp->eth_regs->ethhash1);
	}

	spin_lock_irqsave(&lp->lock, flags);
	writel(recognise, &lp->eth_regs->etharc);
	spin_unlock_irqrestore(&lp->lock, flags);
}

static void korina_tx(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	struct dma_desc *td = &lp->td_ring[lp->tx_next_done];
	u32 devcs;
	u32 dmas;

	spin_lock(&lp->lock);

	/* Process all desc that are done */
	while (IS_DMA_FINISHED(td->control)) {
		if (lp->tx_full == 1) {
			netif_wake_queue(dev);
			lp->tx_full = 0;
		}

		devcs = lp->td_ring[lp->tx_next_done].devcs;
		if ((devcs & (ETH_TX_FD | ETH_TX_LD)) !=
				(ETH_TX_FD | ETH_TX_LD)) {
			dev->stats.tx_errors++;
			dev->stats.tx_dropped++;

			/* Should never happen */
			printk(KERN_ERR "%s: split tx ignored\n",
							dev->name);
		} else if (devcs & ETH_TX_TOK) {
			dev->stats.tx_packets++;
			dev->stats.tx_bytes +=
					lp->tx_skb[lp->tx_next_done]->len;
		} else {
			dev->stats.tx_errors++;
			dev->stats.tx_dropped++;

			/* Underflow */
			if (devcs & ETH_TX_UND)
				dev->stats.tx_fifo_errors++;

			/* Oversized frame */
			if (devcs & ETH_TX_OF)
				dev->stats.tx_aborted_errors++;

			/* Excessive deferrals */
			if (devcs & ETH_TX_ED)
				dev->stats.tx_carrier_errors++;

			/* Collisions: medium busy */
			if (devcs & ETH_TX_EC)
				dev->stats.collisions++;

			/* Late collision */
			if (devcs & ETH_TX_LC)
				dev->stats.tx_window_errors++;
		}

		/* We must always free the original skb */
		if (lp->tx_skb[lp->tx_next_done]) {
			dev_kfree_skb_any(lp->tx_skb[lp->tx_next_done]);
			lp->tx_skb[lp->tx_next_done] = NULL;
		}

		lp->td_ring[lp->tx_next_done].control = DMA_DESC_IOF;
		lp->td_ring[lp->tx_next_done].devcs = ETH_TX_FD | ETH_TX_LD;
		lp->td_ring[lp->tx_next_done].link = 0;
		lp->td_ring[lp->tx_next_done].ca = 0;
		lp->tx_count--;

		/* Go on to next transmission */
		lp->tx_next_done = (lp->tx_next_done + 1) & KORINA_TDS_MASK;
		td = &lp->td_ring[lp->tx_next_done];

	}

	/* Clear the DMA status register */
	dmas = readl(&lp->tx_dma_regs->dmas);
	writel(~dmas, &lp->tx_dma_regs->dmas);

	writel(readl(&lp->tx_dma_regs->dmasm) &
			~(DMA_STAT_FINI | DMA_STAT_ERR),
			&lp->tx_dma_regs->dmasm);

	spin_unlock(&lp->lock);
}

static irqreturn_t
korina_tx_dma_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct korina_private *lp = netdev_priv(dev);
	u32 dmas, dmasm;
	irqreturn_t retval;

	dmas = readl(&lp->tx_dma_regs->dmas);

	if (dmas & (DMA_STAT_FINI | DMA_STAT_ERR)) {
		dmasm = readl(&lp->tx_dma_regs->dmasm);
		writel(dmasm | (DMA_STAT_FINI | DMA_STAT_ERR),
				&lp->tx_dma_regs->dmasm);

		korina_tx(dev);

		if (lp->tx_chain_status == desc_filled &&
			(readl(&(lp->tx_dma_regs->dmandptr)) == 0)) {
			writel(CPHYSADDR(&lp->td_ring[lp->tx_chain_head]),
				&(lp->tx_dma_regs->dmandptr));
			lp->tx_chain_status = desc_empty;
			lp->tx_chain_head = lp->tx_chain_tail;
			dev->trans_start = jiffies;
		}
		if (dmas & DMA_STAT_ERR)
			printk(KERN_ERR "%s: DMA error\n", dev->name);

		retval = IRQ_HANDLED;
	} else
		retval = IRQ_NONE;

	return retval;
}


static void korina_check_media(struct net_device *dev, unsigned int init_media)
{
	struct korina_private *lp = netdev_priv(dev);

	mii_check_media(&lp->mii_if, 0, init_media);

	if (lp->mii_if.full_duplex)
		writel(readl(&lp->eth_regs->ethmac2) | ETH_MAC2_FD,
						&lp->eth_regs->ethmac2);
	else
		writel(readl(&lp->eth_regs->ethmac2) & ~ETH_MAC2_FD,
						&lp->eth_regs->ethmac2);
}

static void korina_poll_media(unsigned long data)
{
	struct net_device *dev = (struct net_device *) data;
	struct korina_private *lp = netdev_priv(dev);

	korina_check_media(dev, 0);
	mod_timer(&lp->media_check_timer, jiffies + HZ);
}

static void korina_set_carrier(struct mii_if_info *mii)
{
	if (mii->force_media) {
		/* autoneg is off: Link is always assumed to be up */
		if (!netif_carrier_ok(mii->dev))
			netif_carrier_on(mii->dev);
	} else  /* Let MMI library update carrier status */
		korina_check_media(mii->dev, 0);
}

static int korina_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
	struct korina_private *lp = netdev_priv(dev);
	struct mii_ioctl_data *data = if_mii(rq);
	int rc;

	if (!netif_running(dev))
		return -EINVAL;
	spin_lock_irq(&lp->lock);
	rc = generic_mii_ioctl(&lp->mii_if, data, cmd, NULL);
	spin_unlock_irq(&lp->lock);
	korina_set_carrier(&lp->mii_if);

	return rc;
}

/* ethtool helpers */
static void netdev_get_drvinfo(struct net_device *dev,
			struct ethtool_drvinfo *info)
{
	struct korina_private *lp = netdev_priv(dev);

	strcpy(info->driver, DRV_NAME);
	strcpy(info->version, DRV_VERSION);
	strcpy(info->bus_info, lp->dev->name);
}

static int netdev_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	struct korina_private *lp = netdev_priv(dev);
	int rc;

	spin_lock_irq(&lp->lock);
	rc = mii_ethtool_gset(&lp->mii_if, cmd);
	spin_unlock_irq(&lp->lock);

	return rc;
}

static int netdev_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	struct korina_private *lp = netdev_priv(dev);
	int rc;

	spin_lock_irq(&lp->lock);
	rc = mii_ethtool_sset(&lp->mii_if, cmd);
	spin_unlock_irq(&lp->lock);
	korina_set_carrier(&lp->mii_if);

	return rc;
}

static u32 netdev_get_link(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);

	return mii_link_ok(&lp->mii_if);
}

static const struct ethtool_ops netdev_ethtool_ops = {
	.get_drvinfo            = netdev_get_drvinfo,
	.get_settings           = netdev_get_settings,
	.set_settings           = netdev_set_settings,
	.get_link               = netdev_get_link,
};

static int korina_alloc_ring(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	struct sk_buff *skb;
	int i;

	/* Initialize the transmit descriptors */
	for (i = 0; i < KORINA_NUM_TDS; i++) {
		lp->td_ring[i].control = DMA_DESC_IOF;
		lp->td_ring[i].devcs = ETH_TX_FD | ETH_TX_LD;
		lp->td_ring[i].ca = 0;
		lp->td_ring[i].link = 0;
	}
	lp->tx_next_done = lp->tx_chain_head = lp->tx_chain_tail =
			lp->tx_full = lp->tx_count = 0;
	lp->tx_chain_status = desc_empty;

	/* Initialize the receive descriptors */
	for (i = 0; i < KORINA_NUM_RDS; i++) {
		skb = dev_alloc_skb(KORINA_RBSIZE + 2);
		if (!skb)
			return -ENOMEM;
		skb_reserve(skb, 2);
		lp->rx_skb[i] = skb;
		lp->rd_ring[i].control = DMA_DESC_IOD |
				DMA_COUNT(KORINA_RBSIZE);
		lp->rd_ring[i].devcs = 0;
		lp->rd_ring[i].ca = CPHYSADDR(skb->data);
		lp->rd_ring[i].link = CPHYSADDR(&lp->rd_ring[i+1]);
	}

	/* loop back receive descriptors, so the last
	 * descriptor points to the first one */
	lp->rd_ring[i - 1].link = CPHYSADDR(&lp->rd_ring[0]);
	lp->rd_ring[i - 1].control |= DMA_DESC_COD;

	lp->rx_next_done  = 0;
	lp->rx_chain_head = 0;
	lp->rx_chain_tail = 0;
	lp->rx_chain_status = desc_empty;

	return 0;
}

static void korina_free_ring(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	int i;

	for (i = 0; i < KORINA_NUM_RDS; i++) {
		lp->rd_ring[i].control = 0;
		if (lp->rx_skb[i])
			dev_kfree_skb_any(lp->rx_skb[i]);
		lp->rx_skb[i] = NULL;
	}

	for (i = 0; i < KORINA_NUM_TDS; i++) {
		lp->td_ring[i].control = 0;
		if (lp->tx_skb[i])
			dev_kfree_skb_any(lp->tx_skb[i]);
		lp->tx_skb[i] = NULL;
	}
}

/*
 * Initialize the RC32434 ethernet controller.
 */
static int korina_init(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);

	/* Disable DMA */
	korina_abort_tx(dev);
	korina_abort_rx(dev);

	/* reset ethernet logic */
	writel(0, &lp->eth_regs->ethintfc);
	while ((readl(&lp->eth_regs->ethintfc) & ETH_INT_FC_RIP))
		dev->trans_start = jiffies;

	/* Enable Ethernet Interface */
	writel(ETH_INT_FC_EN, &lp->eth_regs->ethintfc);

	/* Allocate rings */
	if (korina_alloc_ring(dev)) {
		printk(KERN_ERR "%s: descriptor allocation failed\n", dev->name);
		korina_free_ring(dev);
		return -ENOMEM;
	}

	writel(0, &lp->rx_dma_regs->dmas);
	/* Start Rx DMA */
	korina_start_rx(lp, &lp->rd_ring[0]);

	writel(readl(&lp->tx_dma_regs->dmasm) &
			~(DMA_STAT_FINI | DMA_STAT_ERR),
			&lp->tx_dma_regs->dmasm);
	writel(readl(&lp->rx_dma_regs->dmasm) &
			~(DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR),
			&lp->rx_dma_regs->dmasm);

	/* Accept only packets destined for this Ethernet device address */
	writel(ETH_ARC_AB, &lp->eth_regs->etharc);

	/* Set all Ether station address registers to their initial values */
	writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal0);
	writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah0);

	writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal1);
	writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah1);

	writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal2);
	writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah2);

	writel(STATION_ADDRESS_LOW(dev), &lp->eth_regs->ethsal3);
	writel(STATION_ADDRESS_HIGH(dev), &lp->eth_regs->ethsah3);


	/* Frame Length Checking, Pad Enable, CRC Enable, Full Duplex set */
	writel(ETH_MAC2_PE | ETH_MAC2_CEN | ETH_MAC2_FD,
			&lp->eth_regs->ethmac2);

	/* Back to back inter-packet-gap */
	writel(0x15, &lp->eth_regs->ethipgt);
	/* Non - Back to back inter-packet-gap */
	writel(0x12, &lp->eth_regs->ethipgr);

	/* Management Clock Prescaler Divisor
	 * Clock independent setting */
	writel(((idt_cpu_freq) / MII_CLOCK + 1) & ~1,
		       &lp->eth_regs->ethmcp);

	/* don't transmit until fifo contains 48b */
	writel(48, &lp->eth_regs->ethfifott);

	writel(ETH_MAC1_RE, &lp->eth_regs->ethmac1);

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

	return 0;
}

/*
 * Restart the RC32434 ethernet controller.
 * FIXME: check the return status where we call it
 */
static int korina_restart(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	int ret;

	/*
	 * Disable interrupts
	 */
	disable_irq(lp->rx_irq);
	disable_irq(lp->tx_irq);
	disable_irq(lp->ovr_irq);
	disable_irq(lp->und_irq);

	writel(readl(&lp->tx_dma_regs->dmasm) |
				DMA_STAT_FINI | DMA_STAT_ERR,
				&lp->tx_dma_regs->dmasm);
	writel(readl(&lp->rx_dma_regs->dmasm) |
				DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR,
				&lp->rx_dma_regs->dmasm);

	korina_free_ring(dev);

	napi_disable(&lp->napi);

	ret = korina_init(dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: cannot restart device\n", dev->name);
		return ret;
	}
	korina_multicast_list(dev);

	enable_irq(lp->und_irq);
	enable_irq(lp->ovr_irq);
	enable_irq(lp->tx_irq);
	enable_irq(lp->rx_irq);

	return ret;
}

static void korina_clear_and_restart(struct net_device *dev, u32 value)
{
	struct korina_private *lp = netdev_priv(dev);

	netif_stop_queue(dev);
	writel(value, &lp->eth_regs->ethintfc);
	korina_restart(dev);
}

/* Ethernet Tx Underflow interrupt */
static irqreturn_t korina_und_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct korina_private *lp = netdev_priv(dev);
	unsigned int und;

	spin_lock(&lp->lock);

	und = readl(&lp->eth_regs->ethintfc);

	if (und & ETH_INT_FC_UND)
		korina_clear_and_restart(dev, und & ~ETH_INT_FC_UND);

	spin_unlock(&lp->lock);

	return IRQ_HANDLED;
}

static void korina_tx_timeout(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	unsigned long flags;

	spin_lock_irqsave(&lp->lock, flags);
	korina_restart(dev);
	spin_unlock_irqrestore(&lp->lock, flags);
}

/* Ethernet Rx Overflow interrupt */
static irqreturn_t
korina_ovr_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct korina_private *lp = netdev_priv(dev);
	unsigned int ovr;

	spin_lock(&lp->lock);
	ovr = readl(&lp->eth_regs->ethintfc);

	if (ovr & ETH_INT_FC_OVR)
		korina_clear_and_restart(dev, ovr & ~ETH_INT_FC_OVR);

	spin_unlock(&lp->lock);

	return IRQ_HANDLED;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void korina_poll_controller(struct net_device *dev)
{
	disable_irq(dev->irq);
	korina_tx_dma_interrupt(dev->irq, dev);
	enable_irq(dev->irq);
}
#endif

static int korina_open(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	int ret;

	/* Initialize */
	ret = korina_init(dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: cannot open device\n", dev->name);
		goto out;
	}

	/* Install the interrupt handler
	 * that handles the Done Finished
	 * Ovr and Und Events */
	ret = request_irq(lp->rx_irq, &korina_rx_dma_interrupt,
			IRQF_DISABLED, "Korina ethernet Rx", dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: unable to get Rx DMA IRQ %d\n",
		    dev->name, lp->rx_irq);
		goto err_release;
	}
	ret = request_irq(lp->tx_irq, &korina_tx_dma_interrupt,
			IRQF_DISABLED, "Korina ethernet Tx", dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: unable to get Tx DMA IRQ %d\n",
		    dev->name, lp->tx_irq);
		goto err_free_rx_irq;
	}

	/* Install handler for overrun error. */
	ret = request_irq(lp->ovr_irq, &korina_ovr_interrupt,
			IRQF_DISABLED, "Ethernet Overflow", dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: unable to get OVR IRQ %d\n",
		    dev->name, lp->ovr_irq);
		goto err_free_tx_irq;
	}

	/* Install handler for underflow error. */
	ret = request_irq(lp->und_irq, &korina_und_interrupt,
			IRQF_DISABLED, "Ethernet Underflow", dev);
	if (ret < 0) {
		printk(KERN_ERR "%s: unable to get UND IRQ %d\n",
		    dev->name, lp->und_irq);
		goto err_free_ovr_irq;
	}
	mod_timer(&lp->media_check_timer, jiffies + 1);
out:
	return ret;

err_free_ovr_irq:
	free_irq(lp->ovr_irq, dev);
err_free_tx_irq:
	free_irq(lp->tx_irq, dev);
err_free_rx_irq:
	free_irq(lp->rx_irq, dev);
err_release:
	korina_free_ring(dev);
	goto out;
}

static int korina_close(struct net_device *dev)
{
	struct korina_private *lp = netdev_priv(dev);
	u32 tmp;

	del_timer(&lp->media_check_timer);

	/* Disable interrupts */
	disable_irq(lp->rx_irq);
	disable_irq(lp->tx_irq);
	disable_irq(lp->ovr_irq);
	disable_irq(lp->und_irq);

	korina_abort_tx(dev);
	tmp = readl(&lp->tx_dma_regs->dmasm);
	tmp = tmp | DMA_STAT_FINI | DMA_STAT_ERR;
	writel(tmp, &lp->tx_dma_regs->dmasm);

	korina_abort_rx(dev);
	tmp = readl(&lp->rx_dma_regs->dmasm);
	tmp = tmp | DMA_STAT_DONE | DMA_STAT_HALT | DMA_STAT_ERR;
	writel(tmp, &lp->rx_dma_regs->dmasm);

	korina_free_ring(dev);

	napi_disable(&lp->napi);

	free_irq(lp->rx_irq, dev);
	free_irq(lp->tx_irq, dev);
	free_irq(lp->ovr_irq, dev);
	free_irq(lp->und_irq, dev);

	return 0;
}

static const struct net_device_ops korina_netdev_ops = {
	.ndo_open		= korina_open,
	.ndo_stop		= korina_close,
	.ndo_start_xmit		= korina_send_packet,
	.ndo_set_multicast_list	= korina_multicast_list,
	.ndo_tx_timeout		= korina_tx_timeout,
	.ndo_do_ioctl		= korina_ioctl,
	.ndo_change_mtu		= eth_change_mtu,
	.ndo_validate_addr	= eth_validate_addr,
	.ndo_set_mac_address	= eth_mac_addr,
#ifdef CONFIG_NET_POLL_CONTROLLER
	.ndo_poll_controller	= korina_poll_controller,
#endif
};

static int korina_probe(struct platform_device *pdev)
{
	struct korina_device *bif = platform_get_drvdata(pdev);
	struct korina_private *lp;
	struct net_device *dev;
	struct resource *r;
	int rc;

	dev = alloc_etherdev(sizeof(struct korina_private));
	if (!dev) {
		printk(KERN_ERR DRV_NAME ": alloc_etherdev failed\n");
		return -ENOMEM;
	}
	SET_NETDEV_DEV(dev, &pdev->dev);
	lp = netdev_priv(dev);

	bif->dev = dev;
	memcpy(dev->dev_addr, bif->mac, 6);

	lp->rx_irq = platform_get_irq_byname(pdev, "korina_rx");
	lp->tx_irq = platform_get_irq_byname(pdev, "korina_tx");
	lp->ovr_irq = platform_get_irq_byname(pdev, "korina_ovr");
	lp->und_irq = platform_get_irq_byname(pdev, "korina_und");

	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "korina_regs");
	dev->base_addr = r->start;
	lp->eth_regs = ioremap_nocache(r->start, r->end - r->start);
	if (!lp->eth_regs) {
		printk(KERN_ERR DRV_NAME ": cannot remap registers\n");
		rc = -ENXIO;
		goto probe_err_out;
	}

	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "korina_dma_rx");
	lp->rx_dma_regs = ioremap_nocache(r->start, r->end - r->start);
	if (!lp->rx_dma_regs) {
		printk(KERN_ERR DRV_NAME ": cannot remap Rx DMA registers\n");
		rc = -ENXIO;
		goto probe_err_dma_rx;
	}

	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "korina_dma_tx");
	lp->tx_dma_regs = ioremap_nocache(r->start, r->end - r->start);
	if (!lp->tx_dma_regs) {
		printk(KERN_ERR DRV_NAME ": cannot remap Tx DMA registers\n");
		rc = -ENXIO;
		goto probe_err_dma_tx;
	}

	lp->td_ring = kmalloc(TD_RING_SIZE + RD_RING_SIZE, GFP_KERNEL);
	if (!lp->td_ring) {
		printk(KERN_ERR DRV_NAME ": cannot allocate descriptors\n");
		rc = -ENXIO;
		goto probe_err_td_ring;
	}

	dma_cache_inv((unsigned long)(lp->td_ring),
			TD_RING_SIZE + RD_RING_SIZE);

	/* now convert TD_RING pointer to KSEG1 */
	lp->td_ring = (struct dma_desc *)KSEG1ADDR(lp->td_ring);
	lp->rd_ring = &lp->td_ring[KORINA_NUM_TDS];

	spin_lock_init(&lp->lock);
	/* just use the rx dma irq */
	dev->irq = lp->rx_irq;
	lp->dev = dev;

	dev->netdev_ops = &korina_netdev_ops;
	dev->ethtool_ops = &netdev_ethtool_ops;
	dev->watchdog_timeo = TX_TIMEOUT;
	netif_napi_add(dev, &lp->napi, korina_poll, 64);

	lp->phy_addr = (((lp->rx_irq == 0x2c? 1:0) << 8) | 0x05);
	lp->mii_if.dev = dev;
	lp->mii_if.mdio_read = mdio_read;
	lp->mii_if.mdio_write = mdio_write;
	lp->mii_if.phy_id = lp->phy_addr;
	lp->mii_if.phy_id_mask = 0x1f;
	lp->mii_if.reg_num_mask = 0x1f;

	rc = register_netdev(dev);
	if (rc < 0) {
		printk(KERN_ERR DRV_NAME
			": cannot register net device: %d\n", rc);
		goto probe_err_register;
	}
	setup_timer(&lp->media_check_timer, korina_poll_media, (unsigned long) dev);

	printk(KERN_INFO "%s: " DRV_NAME "-" DRV_VERSION " " DRV_RELDATE "\n",
			dev->name);
out:
	return rc;

probe_err_register:
	kfree(lp->td_ring);
probe_err_td_ring:
	iounmap(lp->tx_dma_regs);
probe_err_dma_tx:
	iounmap(lp->rx_dma_regs);
probe_err_dma_rx:
	iounmap(lp->eth_regs);
probe_err_out:
	free_netdev(dev);
	goto out;
}

static int korina_remove(struct platform_device *pdev)
{
	struct korina_device *bif = platform_get_drvdata(pdev);
	struct korina_private *lp = netdev_priv(bif->dev);

	iounmap(lp->eth_regs);
	iounmap(lp->rx_dma_regs);
	iounmap(lp->tx_dma_regs);

	platform_set_drvdata(pdev, NULL);
	unregister_netdev(bif->dev);
	free_netdev(bif->dev);

	return 0;
}

static struct platform_driver korina_driver = {
	.driver.name = "korina",
	.probe = korina_probe,
	.remove = korina_remove,
};

static int __init korina_init_module(void)
{
	return platform_driver_register(&korina_driver);
}

static void korina_cleanup_module(void)
{
	return platform_driver_unregister(&korina_driver);
}

module_init(korina_init_module);
module_exit(korina_cleanup_module);

MODULE_AUTHOR("Philip Rischel <rischelp@idt.com>");
MODULE_AUTHOR("Felix Fietkau <nbd@openwrt.org>");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("IDT RC32434 (Korina) Ethernet driver");
MODULE_LICENSE("GPL");
