/*
 * Copyright (C) 2006, 2007 Eugene Konev
 *
 * 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 program is distributed in the hope that 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
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/delay.h>

#include <linux/netdevice.h>
#include <linux/if_vlan.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/skbuff.h>
#include <linux/mii.h>
#include <linux/phy.h>
#include <linux/phy_fixed.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/clk.h>
#include <linux/gpio.h>
#include <linux/atomic.h>

#include <asm/mach-ar7/ar7.h>

MODULE_AUTHOR("Eugene Konev <ejka@imfi.kspu.ru>");
MODULE_DESCRIPTION("TI AR7 ethernet driver (CPMAC)");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:cpmac");

static int debug_level = 8;
static int dumb_switch;

/* Next 2 are only used in cpmac_probe, so it's pointless to change them */
module_param(debug_level, int, 0444);
module_param(dumb_switch, int, 0444);

MODULE_PARM_DESC(debug_level, "Number of NETIF_MSG bits to enable");
MODULE_PARM_DESC(dumb_switch, "Assume switch is not connected to MDIO bus");

#define CPMAC_VERSION "0.5.2"
/* frame size + 802.1q tag + FCS size */
#define CPMAC_SKB_SIZE		(ETH_FRAME_LEN + ETH_FCS_LEN + VLAN_HLEN)
#define CPMAC_QUEUES	8

/* Ethernet registers */
#define CPMAC_TX_CONTROL		0x0004
#define CPMAC_TX_TEARDOWN		0x0008
#define CPMAC_RX_CONTROL		0x0014
#define CPMAC_RX_TEARDOWN		0x0018
#define CPMAC_MBP			0x0100
#define MBP_RXPASSCRC			0x40000000
#define MBP_RXQOS			0x20000000
#define MBP_RXNOCHAIN			0x10000000
#define MBP_RXCMF			0x01000000
#define MBP_RXSHORT			0x00800000
#define MBP_RXCEF			0x00400000
#define MBP_RXPROMISC			0x00200000
#define MBP_PROMISCCHAN(channel)	(((channel) & 0x7) << 16)
#define MBP_RXBCAST			0x00002000
#define MBP_BCASTCHAN(channel)		(((channel) & 0x7) << 8)
#define MBP_RXMCAST			0x00000020
#define MBP_MCASTCHAN(channel)		((channel) & 0x7)
#define CPMAC_UNICAST_ENABLE		0x0104
#define CPMAC_UNICAST_CLEAR		0x0108
#define CPMAC_MAX_LENGTH		0x010c
#define CPMAC_BUFFER_OFFSET		0x0110
#define CPMAC_MAC_CONTROL		0x0160
#define MAC_TXPTYPE			0x00000200
#define MAC_TXPACE			0x00000040
#define MAC_MII				0x00000020
#define MAC_TXFLOW			0x00000010
#define MAC_RXFLOW			0x00000008
#define MAC_MTEST			0x00000004
#define MAC_LOOPBACK			0x00000002
#define MAC_FDX				0x00000001
#define CPMAC_MAC_STATUS		0x0164
#define MAC_STATUS_QOS			0x00000004
#define MAC_STATUS_RXFLOW		0x00000002
#define MAC_STATUS_TXFLOW		0x00000001
#define CPMAC_TX_INT_ENABLE		0x0178
#define CPMAC_TX_INT_CLEAR		0x017c
#define CPMAC_MAC_INT_VECTOR		0x0180
#define MAC_INT_STATUS			0x00080000
#define MAC_INT_HOST			0x00040000
#define MAC_INT_RX			0x00020000
#define MAC_INT_TX			0x00010000
#define CPMAC_MAC_EOI_VECTOR		0x0184
#define CPMAC_RX_INT_ENABLE		0x0198
#define CPMAC_RX_INT_CLEAR		0x019c
#define CPMAC_MAC_INT_ENABLE		0x01a8
#define CPMAC_MAC_INT_CLEAR		0x01ac
#define CPMAC_MAC_ADDR_LO(channel)	(0x01b0 + (channel) * 4)
#define CPMAC_MAC_ADDR_MID		0x01d0
#define CPMAC_MAC_ADDR_HI		0x01d4
#define CPMAC_MAC_HASH_LO		0x01d8
#define CPMAC_MAC_HASH_HI		0x01dc
#define CPMAC_TX_PTR(channel)		(0x0600 + (channel) * 4)
#define CPMAC_RX_PTR(channel)		(0x0620 + (channel) * 4)
#define CPMAC_TX_ACK(channel)		(0x0640 + (channel) * 4)
#define CPMAC_RX_ACK(channel)		(0x0660 + (channel) * 4)
#define CPMAC_REG_END			0x0680

/* Rx/Tx statistics
 * TODO: use some of them to fill stats in cpmac_stats()
 */
#define CPMAC_STATS_RX_GOOD		0x0200
#define CPMAC_STATS_RX_BCAST		0x0204
#define CPMAC_STATS_RX_MCAST		0x0208
#define CPMAC_STATS_RX_PAUSE		0x020c
#define CPMAC_STATS_RX_CRC		0x0210
#define CPMAC_STATS_RX_ALIGN		0x0214
#define CPMAC_STATS_RX_OVER		0x0218
#define CPMAC_STATS_RX_JABBER		0x021c
#define CPMAC_STATS_RX_UNDER		0x0220
#define CPMAC_STATS_RX_FRAG		0x0224
#define CPMAC_STATS_RX_FILTER		0x0228
#define CPMAC_STATS_RX_QOSFILTER	0x022c
#define CPMAC_STATS_RX_OCTETS		0x0230

#define CPMAC_STATS_TX_GOOD		0x0234
#define CPMAC_STATS_TX_BCAST		0x0238
#define CPMAC_STATS_TX_MCAST		0x023c
#define CPMAC_STATS_TX_PAUSE		0x0240
#define CPMAC_STATS_TX_DEFER		0x0244
#define CPMAC_STATS_TX_COLLISION	0x0248
#define CPMAC_STATS_TX_SINGLECOLL	0x024c
#define CPMAC_STATS_TX_MULTICOLL	0x0250
#define CPMAC_STATS_TX_EXCESSCOLL	0x0254
#define CPMAC_STATS_TX_LATECOLL		0x0258
#define CPMAC_STATS_TX_UNDERRUN		0x025c
#define CPMAC_STATS_TX_CARRIERSENSE	0x0260
#define CPMAC_STATS_TX_OCTETS		0x0264

#define cpmac_read(base, reg)		(readl((void __iomem *)(base) + (reg)))
#define cpmac_write(base, reg, val)	(writel(val, (void __iomem *)(base) + \
						(reg)))

/* MDIO bus */
#define CPMAC_MDIO_VERSION		0x0000
#define CPMAC_MDIO_CONTROL		0x0004
#define MDIOC_IDLE			0x80000000
#define MDIOC_ENABLE			0x40000000
#define MDIOC_PREAMBLE			0x00100000
#define MDIOC_FAULT			0x00080000
#define MDIOC_FAULTDETECT		0x00040000
#define MDIOC_INTTEST			0x00020000
#define MDIOC_CLKDIV(div)		((div) & 0xff)
#define CPMAC_MDIO_ALIVE		0x0008
#define CPMAC_MDIO_LINK			0x000c
#define CPMAC_MDIO_ACCESS(channel)	(0x0080 + (channel) * 8)
#define MDIO_BUSY			0x80000000
#define MDIO_WRITE			0x40000000
#define MDIO_REG(reg)			(((reg) & 0x1f) << 21)
#define MDIO_PHY(phy)			(((phy) & 0x1f) << 16)
#define MDIO_DATA(data)			((data) & 0xffff)
#define CPMAC_MDIO_PHYSEL(channel)	(0x0084 + (channel) * 8)
#define PHYSEL_LINKSEL			0x00000040
#define PHYSEL_LINKINT			0x00000020

struct cpmac_desc {
	u32 hw_next;
	u32 hw_data;
	u16 buflen;
	u16 bufflags;
	u16 datalen;
	u16 dataflags;
#define CPMAC_SOP			0x8000
#define CPMAC_EOP			0x4000
#define CPMAC_OWN			0x2000
#define CPMAC_EOQ			0x1000
	struct sk_buff *skb;
	struct cpmac_desc *next;
	struct cpmac_desc *prev;
	dma_addr_t mapping;
	dma_addr_t data_mapping;
};

struct cpmac_priv {
	spinlock_t lock;
	spinlock_t rx_lock;
	struct cpmac_desc *rx_head;
	int ring_size;
	struct cpmac_desc *desc_ring;
	dma_addr_t dma_ring;
	void __iomem *regs;
	struct mii_bus *mii_bus;
	char phy_name[MII_BUS_ID_SIZE + 3];
	int oldlink, oldspeed, oldduplex;
	u32 msg_enable;
	struct net_device *dev;
	struct work_struct reset_work;
	struct platform_device *pdev;
	struct napi_struct napi;
	atomic_t reset_pending;
};

static irqreturn_t cpmac_irq(int, void *);
static void cpmac_hw_start(struct net_device *dev);
static void cpmac_hw_stop(struct net_device *dev);
static int cpmac_stop(struct net_device *dev);
static int cpmac_open(struct net_device *dev);

static void cpmac_dump_regs(struct net_device *dev)
{
	int i;
	struct cpmac_priv *priv = netdev_priv(dev);

	for (i = 0; i < CPMAC_REG_END; i += 4) {
		if (i % 16 == 0) {
			if (i)
				printk("\n");
			printk("%s: reg[%p]:", dev->name, priv->regs + i);
		}
		printk(" %08x", cpmac_read(priv->regs, i));
	}
	printk("\n");
}

static void cpmac_dump_desc(struct net_device *dev, struct cpmac_desc *desc)
{
	int i;

	printk("%s: desc[%p]:", dev->name, desc);
	for (i = 0; i < sizeof(*desc) / 4; i++)
		printk(" %08x", ((u32 *)desc)[i]);
	printk("\n");
}

static void cpmac_dump_all_desc(struct net_device *dev)
{
	struct cpmac_priv *priv = netdev_priv(dev);
	struct cpmac_desc *dump = priv->rx_head;

	do {
		cpmac_dump_desc(dev, dump);
		dump = dump->next;
	} while (dump != priv->rx_head);
}

static void cpmac_dump_skb(struct net_device *dev, struct sk_buff *skb)
{
	int i;

	printk("%s: skb 0x%p, len=%d\n", dev->name, skb, skb->len);
	for (i = 0; i < skb->len; i++) {
		if (i % 16 == 0) {
			if (i)
				printk("\n");
			printk("%s: data[%p]:", dev->name, skb->data + i);
		}
		printk(" %02x", ((u8 *)skb->data)[i]);
	}
	printk("\n");
}

static int cpmac_mdio_read(struct mii_bus *bus, int phy_id, int reg)
{
	u32 val;

	while (cpmac_read(bus->priv, CPMAC_MDIO_ACCESS(0)) & MDIO_BUSY)
		cpu_relax();
	cpmac_write(bus->priv, CPMAC_MDIO_ACCESS(0), MDIO_BUSY | MDIO_REG(reg) |
		    MDIO_PHY(phy_id));
	while ((val = cpmac_read(bus->priv, CPMAC_MDIO_ACCESS(0))) & MDIO_BUSY)
		cpu_relax();

	return MDIO_DATA(val);
}

static int cpmac_mdio_write(struct mii_bus *bus, int phy_id,
			    int reg, u16 val)
{
	while (cpmac_read(bus->priv, CPMAC_MDIO_ACCESS(0)) & MDIO_BUSY)
		cpu_relax();
	cpmac_write(bus->priv, CPMAC_MDIO_ACCESS(0), MDIO_BUSY | MDIO_WRITE |
		    MDIO_REG(reg) | MDIO_PHY(phy_id) | MDIO_DATA(val));

	return 0;
}

static int cpmac_mdio_reset(struct mii_bus *bus)
{
	struct clk *cpmac_clk;

	cpmac_clk = clk_get(&bus->dev, "cpmac");
	if (IS_ERR(cpmac_clk)) {
		pr_err("unable to get cpmac clock\n");
		return -1;
	}
	ar7_device_reset(AR7_RESET_BIT_MDIO);
	cpmac_write(bus->priv, CPMAC_MDIO_CONTROL, MDIOC_ENABLE |
		    MDIOC_CLKDIV(clk_get_rate(cpmac_clk) / 2200000 - 1));

	return 0;
}

static struct mii_bus *cpmac_mii;

static void cpmac_set_multicast_list(struct net_device *dev)
{
	struct netdev_hw_addr *ha;
	u8 tmp;
	u32 mbp, bit, hash[2] = { 0, };
	struct cpmac_priv *priv = netdev_priv(dev);

	mbp = cpmac_read(priv->regs, CPMAC_MBP);
	if (dev->flags & IFF_PROMISC) {
		cpmac_write(priv->regs, CPMAC_MBP, (mbp & ~MBP_PROMISCCHAN(0)) |
			    MBP_RXPROMISC);
	} else {
		cpmac_write(priv->regs, CPMAC_MBP, mbp & ~MBP_RXPROMISC);
		if (dev->flags & IFF_ALLMULTI) {
			/* enable all multicast mode */
			cpmac_write(priv->regs, CPMAC_MAC_HASH_LO, 0xffffffff);
			cpmac_write(priv->regs, CPMAC_MAC_HASH_HI, 0xffffffff);
		} else {
			/* cpmac uses some strange mac address hashing
			 * (not crc32)
			 */
			netdev_for_each_mc_addr(ha, dev) {
				bit = 0;
				tmp = ha->addr[0];
				bit  ^= (tmp >> 2) ^ (tmp << 4);
				tmp = ha->addr[1];
				bit  ^= (tmp >> 4) ^ (tmp << 2);
				tmp = ha->addr[2];
				bit  ^= (tmp >> 6) ^ tmp;
				tmp = ha->addr[3];
				bit  ^= (tmp >> 2) ^ (tmp << 4);
				tmp = ha->addr[4];
				bit  ^= (tmp >> 4) ^ (tmp << 2);
				tmp = ha->addr[5];
				bit  ^= (tmp >> 6) ^ tmp;
				bit &= 0x3f;
				hash[bit / 32] |= 1 << (bit % 32);
			}

			cpmac_write(priv->regs, CPMAC_MAC_HASH_LO, hash[0]);
			cpmac_write(priv->regs, CPMAC_MAC_HASH_HI, hash[1]);
		}
	}
}

static struct sk_buff *cpmac_rx_one(struct cpmac_priv *priv,
				    struct cpmac_desc *desc)
{
	struct sk_buff *skb, *result = NULL;

	if (unlikely(netif_msg_hw(priv)))
		cpmac_dump_desc(priv->dev, desc);
	cpmac_write(priv->regs, CPMAC_RX_ACK(0), (u32)desc->mapping);
	if (unlikely(!desc->datalen)) {
		if (netif_msg_rx_err(priv) && net_ratelimit())
			netdev_warn(priv->dev, "rx: spurious interrupt\n");

		return NULL;
	}

	skb = netdev_alloc_skb_ip_align(priv->dev, CPMAC_SKB_SIZE);
	if (likely(skb)) {
		skb_put(desc->skb, desc->datalen);
		desc->skb->protocol = eth_type_trans(desc->skb, priv->dev);
		skb_checksum_none_assert(desc->skb);
		priv->dev->stats.rx_packets++;
		priv->dev->stats.rx_bytes += desc->datalen;
		result = desc->skb;
		dma_unmap_single(&priv->dev->dev, desc->data_mapping,
				 CPMAC_SKB_SIZE, DMA_FROM_DEVICE);
		desc->skb = skb;
		desc->data_mapping = dma_map_single(&priv->dev->dev, skb->data,
						    CPMAC_SKB_SIZE,
						    DMA_FROM_DEVICE);
		desc->hw_data = (u32)desc->data_mapping;
		if (unlikely(netif_msg_pktdata(priv))) {
			netdev_dbg(priv->dev, "received packet:\n");
			cpmac_dump_skb(priv->dev, result);
		}
	} else {
		if (netif_msg_rx_err(priv) && net_ratelimit())
			netdev_warn(priv->dev,
				    "low on skbs, dropping packet\n");

		priv->dev->stats.rx_dropped++;
	}

	desc->buflen = CPMAC_SKB_SIZE;
	desc->dataflags = CPMAC_OWN;

	return result;
}

static int cpmac_poll(struct napi_struct *napi, int budget)
{
	struct sk_buff *skb;
	struct cpmac_desc *desc, *restart;
	struct cpmac_priv *priv = container_of(napi, struct cpmac_priv, napi);
	int received = 0, processed = 0;

	spin_lock(&priv->rx_lock);
	if (unlikely(!priv->rx_head)) {
		if (netif_msg_rx_err(priv) && net_ratelimit())
			netdev_warn(priv->dev, "rx: polling, but no queue\n");

		spin_unlock(&priv->rx_lock);
		napi_complete(napi);
		return 0;
	}

	desc = priv->rx_head;
	restart = NULL;
	while (((desc->dataflags & CPMAC_OWN) == 0) && (received < budget)) {
		processed++;

		if ((desc->dataflags & CPMAC_EOQ) != 0) {
			/* The last update to eoq->hw_next didn't happen
			 * soon enough, and the receiver stopped here.
			 * Remember this descriptor so we can restart
			 * the receiver after freeing some space.
			 */
			if (unlikely(restart)) {
				if (netif_msg_rx_err(priv))
					netdev_err(priv->dev, "poll found a"
						   " duplicate EOQ: %p and %p\n",
						   restart, desc);
				goto fatal_error;
			}

			restart = desc->next;
		}

		skb = cpmac_rx_one(priv, desc);
		if (likely(skb)) {
			netif_receive_skb(skb);
			received++;
		}
		desc = desc->next;
	}

	if (desc != priv->rx_head) {
		/* We freed some buffers, but not the whole ring,
		 * add what we did free to the rx list
		 */
		desc->prev->hw_next = (u32)0;
		priv->rx_head->prev->hw_next = priv->rx_head->mapping;
	}

	/* Optimization: If we did not actually process an EOQ (perhaps because
	 * of quota limits), check to see if the tail of the queue has EOQ set.
	 * We should immediately restart in that case so that the receiver can
	 * restart and run in parallel with more packet processing.
	 * This lets us handle slightly larger bursts before running
	 * out of ring space (assuming dev->weight < ring_size)
	 */

	if (!restart &&
	     (priv->rx_head->prev->dataflags & (CPMAC_OWN|CPMAC_EOQ))
		    == CPMAC_EOQ &&
	     (priv->rx_head->dataflags & CPMAC_OWN) != 0) {
		/* reset EOQ so the poll loop (above) doesn't try to
		 * restart this when it eventually gets to this descriptor.
		 */
		priv->rx_head->prev->dataflags &= ~CPMAC_EOQ;
		restart = priv->rx_head;
	}

	if (restart) {
		priv->dev->stats.rx_errors++;
		priv->dev->stats.rx_fifo_errors++;
		if (netif_msg_rx_err(priv) && net_ratelimit())
			netdev_warn(priv->dev, "rx dma ring overrun\n");

		if (unlikely((restart->dataflags & CPMAC_OWN) == 0)) {
			if (netif_msg_drv(priv))
				netdev_err(priv->dev, "cpmac_poll is trying "
					"to restart rx from a descriptor "
					"that's not free: %p\n", restart);
			goto fatal_error;
		}

		cpmac_write(priv->regs, CPMAC_RX_PTR(0), restart->mapping);
	}

	priv->rx_head = desc;
	spin_unlock(&priv->rx_lock);
	if (unlikely(netif_msg_rx_status(priv)))
		netdev_dbg(priv->dev, "poll processed %d packets\n", received);

	if (processed == 0) {
		/* we ran out of packets to read,
		 * revert to interrupt-driven mode
		 */
		napi_complete(napi);
		cpmac_write(priv->regs, CPMAC_RX_INT_ENABLE, 1);
		return 0;
	}

	return 1;

fatal_error:
	/* Something went horribly wrong.
	 * Reset hardware to try to recover rather than wedging.
	 */
	if (netif_msg_drv(priv)) {
		netdev_err(priv->dev, "cpmac_poll is confused. "
			   "Resetting hardware\n");
		cpmac_dump_all_desc(priv->dev);
		netdev_dbg(priv->dev, "RX_PTR(0)=0x%08x RX_ACK(0)=0x%08x\n",
			   cpmac_read(priv->regs, CPMAC_RX_PTR(0)),
			   cpmac_read(priv->regs, CPMAC_RX_ACK(0)));
	}

	spin_unlock(&priv->rx_lock);
	napi_complete(napi);
	netif_tx_stop_all_queues(priv->dev);
	napi_disable(&priv->napi);

	atomic_inc(&priv->reset_pending);
	cpmac_hw_stop(priv->dev);
	if (!schedule_work(&priv->reset_work))
		atomic_dec(&priv->reset_pending);

	return 0;

}

static int cpmac_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	int queue;
	unsigned int len;
	struct cpmac_desc *desc;
	struct cpmac_priv *priv = netdev_priv(dev);

	if (unlikely(atomic_read(&priv->reset_pending)))
		return NETDEV_TX_BUSY;

	if (unlikely(skb_padto(skb, ETH_ZLEN)))
		return NETDEV_TX_OK;

	len = max_t(unsigned int, skb->len, ETH_ZLEN);
	queue = skb_get_queue_mapping(skb);
	netif_stop_subqueue(dev, queue);

	desc = &priv->desc_ring[queue];
	if (unlikely(desc->dataflags & CPMAC_OWN)) {
		if (netif_msg_tx_err(priv) && net_ratelimit())
			netdev_warn(dev, "tx dma ring full\n");

		return NETDEV_TX_BUSY;
	}

	spin_lock(&priv->lock);
	spin_unlock(&priv->lock);
	desc->dataflags = CPMAC_SOP | CPMAC_EOP | CPMAC_OWN;
	desc->skb = skb;
	desc->data_mapping = dma_map_single(&dev->dev, skb->data, len,
					    DMA_TO_DEVICE);
	desc->hw_data = (u32)desc->data_mapping;
	desc->datalen = len;
	desc->buflen = len;
	if (unlikely(netif_msg_tx_queued(priv)))
		netdev_dbg(dev, "sending 0x%p, len=%d\n", skb, skb->len);
	if (unlikely(netif_msg_hw(priv)))
		cpmac_dump_desc(dev, desc);
	if (unlikely(netif_msg_pktdata(priv)))
		cpmac_dump_skb(dev, skb);
	cpmac_write(priv->regs, CPMAC_TX_PTR(queue), (u32)desc->mapping);

	return NETDEV_TX_OK;
}

static void cpmac_end_xmit(struct net_device *dev, int queue)
{
	struct cpmac_desc *desc;
	struct cpmac_priv *priv = netdev_priv(dev);

	desc = &priv->desc_ring[queue];
	cpmac_write(priv->regs, CPMAC_TX_ACK(queue), (u32)desc->mapping);
	if (likely(desc->skb)) {
		spin_lock(&priv->lock);
		dev->stats.tx_packets++;
		dev->stats.tx_bytes += desc->skb->len;
		spin_unlock(&priv->lock);
		dma_unmap_single(&dev->dev, desc->data_mapping, desc->skb->len,
				 DMA_TO_DEVICE);

		if (unlikely(netif_msg_tx_done(priv)))
			netdev_dbg(dev, "sent 0x%p, len=%d\n",
				   desc->skb, desc->skb->len);

		dev_kfree_skb_irq(desc->skb);
		desc->skb = NULL;
		if (__netif_subqueue_stopped(dev, queue))
			netif_wake_subqueue(dev, queue);
	} else {
		if (netif_msg_tx_err(priv) && net_ratelimit())
			netdev_warn(dev, "end_xmit: spurious interrupt\n");
		if (__netif_subqueue_stopped(dev, queue))
			netif_wake_subqueue(dev, queue);
	}
}

static void cpmac_hw_stop(struct net_device *dev)
{
	int i;
	struct cpmac_priv *priv = netdev_priv(dev);
	struct plat_cpmac_data *pdata = dev_get_platdata(&priv->pdev->dev);

	ar7_device_reset(pdata->reset_bit);
	cpmac_write(priv->regs, CPMAC_RX_CONTROL,
		    cpmac_read(priv->regs, CPMAC_RX_CONTROL) & ~1);
	cpmac_write(priv->regs, CPMAC_TX_CONTROL,
		    cpmac_read(priv->regs, CPMAC_TX_CONTROL) & ~1);
	for (i = 0; i < 8; i++) {
		cpmac_write(priv->regs, CPMAC_TX_PTR(i), 0);
		cpmac_write(priv->regs, CPMAC_RX_PTR(i), 0);
	}
	cpmac_write(priv->regs, CPMAC_UNICAST_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_RX_INT_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_TX_INT_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_MAC_INT_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_MAC_CONTROL,
		    cpmac_read(priv->regs, CPMAC_MAC_CONTROL) & ~MAC_MII);
}

static void cpmac_hw_start(struct net_device *dev)
{
	int i;
	struct cpmac_priv *priv = netdev_priv(dev);
	struct plat_cpmac_data *pdata = dev_get_platdata(&priv->pdev->dev);

	ar7_device_reset(pdata->reset_bit);
	for (i = 0; i < 8; i++) {
		cpmac_write(priv->regs, CPMAC_TX_PTR(i), 0);
		cpmac_write(priv->regs, CPMAC_RX_PTR(i), 0);
	}
	cpmac_write(priv->regs, CPMAC_RX_PTR(0), priv->rx_head->mapping);

	cpmac_write(priv->regs, CPMAC_MBP, MBP_RXSHORT | MBP_RXBCAST |
		    MBP_RXMCAST);
	cpmac_write(priv->regs, CPMAC_BUFFER_OFFSET, 0);
	for (i = 0; i < 8; i++)
		cpmac_write(priv->regs, CPMAC_MAC_ADDR_LO(i), dev->dev_addr[5]);
	cpmac_write(priv->regs, CPMAC_MAC_ADDR_MID, dev->dev_addr[4]);
	cpmac_write(priv->regs, CPMAC_MAC_ADDR_HI, dev->dev_addr[0] |
		    (dev->dev_addr[1] << 8) | (dev->dev_addr[2] << 16) |
		    (dev->dev_addr[3] << 24));
	cpmac_write(priv->regs, CPMAC_MAX_LENGTH, CPMAC_SKB_SIZE);
	cpmac_write(priv->regs, CPMAC_UNICAST_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_RX_INT_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_TX_INT_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_MAC_INT_CLEAR, 0xff);
	cpmac_write(priv->regs, CPMAC_UNICAST_ENABLE, 1);
	cpmac_write(priv->regs, CPMAC_RX_INT_ENABLE, 1);
	cpmac_write(priv->regs, CPMAC_TX_INT_ENABLE, 0xff);
	cpmac_write(priv->regs, CPMAC_MAC_INT_ENABLE, 3);

	cpmac_write(priv->regs, CPMAC_RX_CONTROL,
		    cpmac_read(priv->regs, CPMAC_RX_CONTROL) | 1);
	cpmac_write(priv->regs, CPMAC_TX_CONTROL,
		    cpmac_read(priv->regs, CPMAC_TX_CONTROL) | 1);
	cpmac_write(priv->regs, CPMAC_MAC_CONTROL,
		    cpmac_read(priv->regs, CPMAC_MAC_CONTROL) | MAC_MII |
		    MAC_FDX);
}

static void cpmac_clear_rx(struct net_device *dev)
{
	struct cpmac_priv *priv = netdev_priv(dev);
	struct cpmac_desc *desc;
	int i;

	if (unlikely(!priv->rx_head))
		return;
	desc = priv->rx_head;
	for (i = 0; i < priv->ring_size; i++) {
		if ((desc->dataflags & CPMAC_OWN) == 0) {
			if (netif_msg_rx_err(priv) && net_ratelimit())
				netdev_warn(dev, "packet dropped\n");
			if (unlikely(netif_msg_hw(priv)))
				cpmac_dump_desc(dev, desc);
			desc->dataflags = CPMAC_OWN;
			dev->stats.rx_dropped++;
		}
		desc->hw_next = desc->next->mapping;
		desc = desc->next;
	}
	priv->rx_head->prev->hw_next = 0;
}

static void cpmac_clear_tx(struct net_device *dev)
{
	struct cpmac_priv *priv = netdev_priv(dev);
	int i;

	if (unlikely(!priv->desc_ring))
		return;
	for (i = 0; i < CPMAC_QUEUES; i++) {
		priv->desc_ring[i].dataflags = 0;
		if (priv->desc_ring[i].skb) {
			dev_kfree_skb_any(priv->desc_ring[i].skb);
			priv->desc_ring[i].skb = NULL;
		}
	}
}

static void cpmac_hw_error(struct work_struct *work)
{
	struct cpmac_priv *priv =
		container_of(work, struct cpmac_priv, reset_work);

	spin_lock(&priv->rx_lock);
	cpmac_clear_rx(priv->dev);
	spin_unlock(&priv->rx_lock);
	cpmac_clear_tx(priv->dev);
	cpmac_hw_start(priv->dev);
	barrier();
	atomic_dec(&priv->reset_pending);

	netif_tx_wake_all_queues(priv->dev);
	cpmac_write(priv->regs, CPMAC_MAC_INT_ENABLE, 3);
}

static void cpmac_check_status(struct net_device *dev)
{
	struct cpmac_priv *priv = netdev_priv(dev);

	u32 macstatus = cpmac_read(priv->regs, CPMAC_MAC_STATUS);
	int rx_channel = (macstatus >> 8) & 7;
	int rx_code = (macstatus >> 12) & 15;
	int tx_channel = (macstatus >> 16) & 7;
	int tx_code = (macstatus >> 20) & 15;

	if (rx_code || tx_code) {
		if (netif_msg_drv(priv) && net_ratelimit()) {
			/* Can't find any documentation on what these
			 * error codes actually are. So just log them and hope..
			 */
			if (rx_code)
				netdev_warn(dev, "host error %d on rx "
					"channel %d (macstatus %08x), resetting\n",
					rx_code, rx_channel, macstatus);
			if (tx_code)
				netdev_warn(dev, "host error %d on tx "
					"channel %d (macstatus %08x), resetting\n",
					tx_code, tx_channel, macstatus);
		}

		netif_tx_stop_all_queues(dev);
		cpmac_hw_stop(dev);
		if (schedule_work(&priv->reset_work))
			atomic_inc(&priv->reset_pending);
		if (unlikely(netif_msg_hw(priv)))
			cpmac_dump_regs(dev);
	}
	cpmac_write(priv->regs, CPMAC_MAC_INT_CLEAR, 0xff);
}

static irqreturn_t cpmac_irq(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct cpmac_priv *priv;
	int queue;
	u32 status;

	priv = netdev_priv(dev);

	status = cpmac_read(priv->regs, CPMAC_MAC_INT_VECTOR);

	if (unlikely(netif_msg_intr(priv)))
		netdev_dbg(dev, "interrupt status: 0x%08x\n", status);

	if (status & MAC_INT_TX)
		cpmac_end_xmit(dev, (status & 7));

	if (status & MAC_INT_RX) {
		queue = (status >> 8) & 7;
		if (napi_schedule_prep(&priv->napi)) {
			cpmac_write(priv->regs, CPMAC_RX_INT_CLEAR, 1 << queue);
			__napi_schedule(&priv->napi);
		}
	}

	cpmac_write(priv->regs, CPMAC_MAC_EOI_VECTOR, 0);

	if (unlikely(status & (MAC_INT_HOST | MAC_INT_STATUS)))
		cpmac_check_status(dev);

	return IRQ_HANDLED;
}

static void cpmac_tx_timeout(struct net_device *dev)
{
	struct cpmac_priv *priv = netdev_priv(dev);

	spin_lock(&priv->lock);
	dev->stats.tx_errors++;
	spin_unlock(&priv->lock);
	if (netif_msg_tx_err(priv) && net_ratelimit())
		netdev_warn(dev, "transmit timeout\n");

	atomic_inc(&priv->reset_pending);
	barrier();
	cpmac_clear_tx(dev);
	barrier();
	atomic_dec(&priv->reset_pending);

	netif_tx_wake_all_queues(priv->dev);
}

static int cpmac_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	if (!(netif_running(dev)))
		return -EINVAL;
	if (!dev->phydev)
		return -EINVAL;

	return phy_mii_ioctl(dev->phydev, ifr, cmd);
}

static void cpmac_get_ringparam(struct net_device *dev,
						struct ethtool_ringparam *ring)
{
	struct cpmac_priv *priv = netdev_priv(dev);

	ring->rx_max_pending = 1024;
	ring->rx_mini_max_pending = 1;
	ring->rx_jumbo_max_pending = 1;
	ring->tx_max_pending = 1;

	ring->rx_pending = priv->ring_size;
	ring->rx_mini_pending = 1;
	ring->rx_jumbo_pending = 1;
	ring->tx_pending = 1;
}

static int cpmac_set_ringparam(struct net_device *dev,
						struct ethtool_ringparam *ring)
{
	struct cpmac_priv *priv = netdev_priv(dev);

	if (netif_running(dev))
		return -EBUSY;
	priv->ring_size = ring->rx_pending;

	return 0;
}

static void cpmac_get_drvinfo(struct net_device *dev,
			      struct ethtool_drvinfo *info)
{
	strlcpy(info->driver, "cpmac", sizeof(info->driver));
	strlcpy(info->version, CPMAC_VERSION, sizeof(info->version));
	snprintf(info->bus_info, sizeof(info->bus_info), "%s", "cpmac");
}

static const struct ethtool_ops cpmac_ethtool_ops = {
	.get_drvinfo = cpmac_get_drvinfo,
	.get_link = ethtool_op_get_link,
	.get_ringparam = cpmac_get_ringparam,
	.set_ringparam = cpmac_set_ringparam,
	.get_link_ksettings = phy_ethtool_get_link_ksettings,
	.set_link_ksettings = phy_ethtool_set_link_ksettings,
};

static void cpmac_adjust_link(struct net_device *dev)
{
	struct cpmac_priv *priv = netdev_priv(dev);
	int new_state = 0;

	spin_lock(&priv->lock);
	if (dev->phydev->link) {
		netif_tx_start_all_queues(dev);
		if (dev->phydev->duplex != priv->oldduplex) {
			new_state = 1;
			priv->oldduplex = dev->phydev->duplex;
		}

		if (dev->phydev->speed != priv->oldspeed) {
			new_state = 1;
			priv->oldspeed = dev->phydev->speed;
		}

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

	if (new_state && netif_msg_link(priv) && net_ratelimit())
		phy_print_status(dev->phydev);

	spin_unlock(&priv->lock);
}

static int cpmac_open(struct net_device *dev)
{
	int i, size, res;
	struct cpmac_priv *priv = netdev_priv(dev);
	struct resource *mem;
	struct cpmac_desc *desc;
	struct sk_buff *skb;

	mem = platform_get_resource_byname(priv->pdev, IORESOURCE_MEM, "regs");
	if (!request_mem_region(mem->start, resource_size(mem), dev->name)) {
		if (netif_msg_drv(priv))
			netdev_err(dev, "failed to request registers\n");

		res = -ENXIO;
		goto fail_reserve;
	}

	priv->regs = ioremap(mem->start, resource_size(mem));
	if (!priv->regs) {
		if (netif_msg_drv(priv))
			netdev_err(dev, "failed to remap registers\n");

		res = -ENXIO;
		goto fail_remap;
	}

	size = priv->ring_size + CPMAC_QUEUES;
	priv->desc_ring = dma_alloc_coherent(&dev->dev,
					     sizeof(struct cpmac_desc) * size,
					     &priv->dma_ring,
					     GFP_KERNEL);
	if (!priv->desc_ring) {
		res = -ENOMEM;
		goto fail_alloc;
	}

	for (i = 0; i < size; i++)
		priv->desc_ring[i].mapping = priv->dma_ring + sizeof(*desc) * i;

	priv->rx_head = &priv->desc_ring[CPMAC_QUEUES];
	for (i = 0, desc = priv->rx_head; i < priv->ring_size; i++, desc++) {
		skb = netdev_alloc_skb_ip_align(dev, CPMAC_SKB_SIZE);
		if (unlikely(!skb)) {
			res = -ENOMEM;
			goto fail_desc;
		}
		desc->skb = skb;
		desc->data_mapping = dma_map_single(&dev->dev, skb->data,
						    CPMAC_SKB_SIZE,
						    DMA_FROM_DEVICE);
		desc->hw_data = (u32)desc->data_mapping;
		desc->buflen = CPMAC_SKB_SIZE;
		desc->dataflags = CPMAC_OWN;
		desc->next = &priv->rx_head[(i + 1) % priv->ring_size];
		desc->next->prev = desc;
		desc->hw_next = (u32)desc->next->mapping;
	}

	priv->rx_head->prev->hw_next = (u32)0;

	res = request_irq(dev->irq, cpmac_irq, IRQF_SHARED, dev->name, dev);
	if (res) {
		if (netif_msg_drv(priv))
			netdev_err(dev, "failed to obtain irq\n");

		goto fail_irq;
	}

	atomic_set(&priv->reset_pending, 0);
	INIT_WORK(&priv->reset_work, cpmac_hw_error);
	cpmac_hw_start(dev);

	napi_enable(&priv->napi);
	dev->phydev->state = PHY_CHANGELINK;
	phy_start(dev->phydev);

	return 0;

fail_irq:
fail_desc:
	for (i = 0; i < priv->ring_size; i++) {
		if (priv->rx_head[i].skb) {
			dma_unmap_single(&dev->dev,
					 priv->rx_head[i].data_mapping,
					 CPMAC_SKB_SIZE,
					 DMA_FROM_DEVICE);
			kfree_skb(priv->rx_head[i].skb);
		}
	}
	dma_free_coherent(&dev->dev, sizeof(struct cpmac_desc) * size,
			  priv->desc_ring, priv->dma_ring);

fail_alloc:
	iounmap(priv->regs);

fail_remap:
	release_mem_region(mem->start, resource_size(mem));

fail_reserve:
	return res;
}

static int cpmac_stop(struct net_device *dev)
{
	int i;
	struct cpmac_priv *priv = netdev_priv(dev);
	struct resource *mem;

	netif_tx_stop_all_queues(dev);

	cancel_work_sync(&priv->reset_work);
	napi_disable(&priv->napi);
	phy_stop(dev->phydev);

	cpmac_hw_stop(dev);

	for (i = 0; i < 8; i++)
		cpmac_write(priv->regs, CPMAC_TX_PTR(i), 0);
	cpmac_write(priv->regs, CPMAC_RX_PTR(0), 0);
	cpmac_write(priv->regs, CPMAC_MBP, 0);

	free_irq(dev->irq, dev);
	iounmap(priv->regs);
	mem = platform_get_resource_byname(priv->pdev, IORESOURCE_MEM, "regs");
	release_mem_region(mem->start, resource_size(mem));
	priv->rx_head = &priv->desc_ring[CPMAC_QUEUES];
	for (i = 0; i < priv->ring_size; i++) {
		if (priv->rx_head[i].skb) {
			dma_unmap_single(&dev->dev,
					 priv->rx_head[i].data_mapping,
					 CPMAC_SKB_SIZE,
					 DMA_FROM_DEVICE);
			kfree_skb(priv->rx_head[i].skb);
		}
	}

	dma_free_coherent(&dev->dev, sizeof(struct cpmac_desc) *
			  (CPMAC_QUEUES + priv->ring_size),
			  priv->desc_ring, priv->dma_ring);

	return 0;
}

static const struct net_device_ops cpmac_netdev_ops = {
	.ndo_open		= cpmac_open,
	.ndo_stop		= cpmac_stop,
	.ndo_start_xmit		= cpmac_start_xmit,
	.ndo_tx_timeout		= cpmac_tx_timeout,
	.ndo_set_rx_mode	= cpmac_set_multicast_list,
	.ndo_do_ioctl		= cpmac_ioctl,
	.ndo_change_mtu		= eth_change_mtu,
	.ndo_validate_addr	= eth_validate_addr,
	.ndo_set_mac_address	= eth_mac_addr,
};

static int external_switch;

static int cpmac_probe(struct platform_device *pdev)
{
	int rc, phy_id;
	char mdio_bus_id[MII_BUS_ID_SIZE];
	struct resource *mem;
	struct cpmac_priv *priv;
	struct net_device *dev;
	struct plat_cpmac_data *pdata;
	struct phy_device *phydev = NULL;

	pdata = dev_get_platdata(&pdev->dev);

	if (external_switch || dumb_switch) {
		strncpy(mdio_bus_id, "fixed-0", MII_BUS_ID_SIZE); /* fixed phys bus */
		phy_id = pdev->id;
	} else {
		for (phy_id = 0; phy_id < PHY_MAX_ADDR; phy_id++) {
			if (!(pdata->phy_mask & (1 << phy_id)))
				continue;
			if (!mdiobus_get_phy(cpmac_mii, phy_id))
				continue;
			strncpy(mdio_bus_id, cpmac_mii->id, MII_BUS_ID_SIZE);
			break;
		}
	}

	if (phy_id == PHY_MAX_ADDR) {
		dev_err(&pdev->dev, "no PHY present, falling back "
			"to switch on MDIO bus 0\n");
		strncpy(mdio_bus_id, "fixed-0", MII_BUS_ID_SIZE); /* fixed phys bus */
		phy_id = pdev->id;
	}
	mdio_bus_id[sizeof(mdio_bus_id) - 1] = '\0';

	dev = alloc_etherdev_mq(sizeof(*priv), CPMAC_QUEUES);
	if (!dev)
		return -ENOMEM;

	SET_NETDEV_DEV(dev, &pdev->dev);
	platform_set_drvdata(pdev, dev);
	priv = netdev_priv(dev);

	priv->pdev = pdev;
	mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
	if (!mem) {
		rc = -ENODEV;
		goto fail;
	}

	dev->irq = platform_get_irq_byname(pdev, "irq");

	dev->netdev_ops = &cpmac_netdev_ops;
	dev->ethtool_ops = &cpmac_ethtool_ops;

	netif_napi_add(dev, &priv->napi, cpmac_poll, 64);

	spin_lock_init(&priv->lock);
	spin_lock_init(&priv->rx_lock);
	priv->dev = dev;
	priv->ring_size = 64;
	priv->msg_enable = netif_msg_init(debug_level, 0xff);
	memcpy(dev->dev_addr, pdata->dev_addr, sizeof(pdata->dev_addr));

	snprintf(priv->phy_name, MII_BUS_ID_SIZE, PHY_ID_FMT,
						mdio_bus_id, phy_id);

	phydev = phy_connect(dev, priv->phy_name, cpmac_adjust_link,
			     PHY_INTERFACE_MODE_MII);

	if (IS_ERR(phydev)) {
		if (netif_msg_drv(priv))
			dev_err(&pdev->dev, "Could not attach to PHY\n");

		rc = PTR_ERR(phydev);
		goto fail;
	}

	rc = register_netdev(dev);
	if (rc) {
		dev_err(&pdev->dev, "Could not register net device\n");
		goto fail;
	}

	if (netif_msg_probe(priv)) {
		dev_info(&pdev->dev, "regs: %p, irq: %d, phy: %s, "
			 "mac: %pM\n", (void *)mem->start, dev->irq,
			 priv->phy_name, dev->dev_addr);
	}

	return 0;

fail:
	free_netdev(dev);
	return rc;
}

static int cpmac_remove(struct platform_device *pdev)
{
	struct net_device *dev = platform_get_drvdata(pdev);

	unregister_netdev(dev);
	free_netdev(dev);

	return 0;
}

static struct platform_driver cpmac_driver = {
	.driver = {
		.name 	= "cpmac",
	},
	.probe 	= cpmac_probe,
	.remove = cpmac_remove,
};

int cpmac_init(void)
{
	u32 mask;
	int i, res;

	cpmac_mii = mdiobus_alloc();
	if (cpmac_mii == NULL)
		return -ENOMEM;

	cpmac_mii->name = "cpmac-mii";
	cpmac_mii->read = cpmac_mdio_read;
	cpmac_mii->write = cpmac_mdio_write;
	cpmac_mii->reset = cpmac_mdio_reset;

	cpmac_mii->priv = ioremap(AR7_REGS_MDIO, 256);

	if (!cpmac_mii->priv) {
		pr_err("Can't ioremap mdio registers\n");
		res = -ENXIO;
		goto fail_alloc;
	}

	/* FIXME: unhardcode gpio&reset bits */
	ar7_gpio_disable(26);
	ar7_gpio_disable(27);
	ar7_device_reset(AR7_RESET_BIT_CPMAC_LO);
	ar7_device_reset(AR7_RESET_BIT_CPMAC_HI);
	ar7_device_reset(AR7_RESET_BIT_EPHY);

	cpmac_mii->reset(cpmac_mii);

	for (i = 0; i < 300; i++) {
		mask = cpmac_read(cpmac_mii->priv, CPMAC_MDIO_ALIVE);
		if (mask)
			break;
		else
			msleep(10);
	}

	mask &= 0x7fffffff;
	if (mask & (mask - 1)) {
		external_switch = 1;
		mask = 0;
	}

	cpmac_mii->phy_mask = ~(mask | 0x80000000);
	snprintf(cpmac_mii->id, MII_BUS_ID_SIZE, "cpmac-1");

	res = mdiobus_register(cpmac_mii);
	if (res)
		goto fail_mii;

	res = platform_driver_register(&cpmac_driver);
	if (res)
		goto fail_cpmac;

	return 0;

fail_cpmac:
	mdiobus_unregister(cpmac_mii);

fail_mii:
	iounmap(cpmac_mii->priv);

fail_alloc:
	mdiobus_free(cpmac_mii);

	return res;
}

void cpmac_exit(void)
{
	platform_driver_unregister(&cpmac_driver);
	mdiobus_unregister(cpmac_mii);
	iounmap(cpmac_mii->priv);
	mdiobus_free(cpmac_mii);
}

module_init(cpmac_init);
module_exit(cpmac_exit);