rt-thread/bsp/at91sam9260/drivers/macb.c

/*
 * File      : macb.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2006, RT-Thread Develop Team
 *
 *  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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2011-03-18     weety      first version
 */

#include <rtthread.h>
#include <netif/ethernetif.h>
#include "lwipopts.h"
#include <at91sam926x.h>
#include "macb.h"

#define MMU_NOCACHE_ADDR(a)      	((rt_uint32_t)a | (1UL<<31))

extern void mmu_clean_dcache(rt_uint32_t buffer, rt_uint32_t size);
extern void mmu_invalidate_dcache(rt_uint32_t buffer, rt_uint32_t size);

/* Cache macros - Packet buffers would be from pbuf pool which is cached */
#define EMAC_VIRT_NOCACHE(addr) (addr)
#define EMAC_CACHE_INVALIDATE(addr, size) \
	mmu_invalidate_dcache((rt_uint32_t)addr, size)
#define EMAC_CACHE_WRITEBACK(addr, size) \
	mmu_clean_dcache((rt_uint32_t)addr, size)
#define EMAC_CACHE_WRITEBACK_INVALIDATE(addr, size) \
	mmu_clean_invalidated_dcache((rt_uint32_t)addr, size)

/* EMAC has BD's in cached memory - so need cache functions */
#define BD_CACHE_INVALIDATE(addr, size)
#define BD_CACHE_WRITEBACK(addr, size)
#define BD_CACHE_WRITEBACK_INVALIDATE(addr, size)

/* EMAC internal utility function */
rt_inline unsigned long emac_virt_to_phys(unsigned long addr)
{
	return addr;
}


#define AT91SAM9260_SRAM0_VIRT_BASE (0x90000000)

#define MACB_TX_SRAM

#if defined(MACB_TX_SRAM)
#define MACB_TX_RING_SIZE		2
#define MACB_TX_BUFFER_SIZE		(1536 * MACB_TX_RING_SIZE)
#define TX_RING_BYTES			(sizeof(struct macb_dma_desc) * MACB_TX_RING_SIZE)
#else
#define MACB_TX_RING_SIZE		16
#define MACB_TX_BUFFER_SIZE		(1536 * MACB_TX_RING_SIZE)
#endif

#define MACB_RX_BUFFER_SIZE		(4096*4)
#define MACB_RX_RING_SIZE		(MACB_RX_BUFFER_SIZE / 128)

#define DEF_TX_RING_PENDING	(MACB_TX_RING_SIZE)

#define TX_RING_GAP(macb)						\
	(MACB_TX_RING_SIZE - (macb)->tx_pending)

#define TX_BUFFS_AVAIL(macb)					\
	(((macb)->tx_tail <= (macb)->tx_head) ?			\
	 (macb)->tx_tail + (macb)->tx_pending - (macb)->tx_head :	\
	 (macb)->tx_tail - (macb)->tx_head - TX_RING_GAP(macb))

#define NEXT_TX(n)		(((n) + 1) & (MACB_TX_RING_SIZE - 1))

#define NEXT_RX(n)		(((n) + 1) & (MACB_RX_RING_SIZE - 1))

/* minimum number of free TX descriptors before waking up TX process */
#define MACB_TX_WAKEUP_THRESH	(MACB_TX_RING_SIZE / 4)

#define MACB_RX_INT_FLAGS	(MACB_BIT(RCOMP) | MACB_BIT(RXUBR)	\
				 | MACB_BIT(ISR_ROVR))

#define MACB_TX_TIMEOUT		1000
#define MACB_AUTONEG_TIMEOUT	5000000	
#define MACB_LINK_TIMEOUT		500000  

#define CONFIG_RMII

struct macb_dma_desc {
	rt_uint32_t	addr;
	rt_uint32_t	ctrl;
};

#define RXADDR_USED		0x00000001
#define RXADDR_WRAP		0x00000002

#define RXBUF_FRMLEN_MASK	0x00000fff
#define RXBUF_FRAME_START	0x00004000
#define RXBUF_FRAME_END		0x00008000
#define RXBUF_TYPEID_MATCH	0x00400000
#define RXBUF_ADDR4_MATCH	0x00800000
#define RXBUF_ADDR3_MATCH	0x01000000
#define RXBUF_ADDR2_MATCH	0x02000000
#define RXBUF_ADDR1_MATCH	0x04000000
#define RXBUF_BROADCAST		0x80000000

#define TXBUF_FRMLEN_MASK	0x000007ff
#define TXBUF_FRAME_END		0x00008000
#define TXBUF_NOCRC		0x00010000
#define TXBUF_EXHAUSTED		0x08000000
#define TXBUF_UNDERRUN		0x10000000
#define TXBUF_MAXRETRY		0x20000000
#define TXBUF_WRAP		0x40000000
#define TXBUF_USED		0x80000000

/* Duplex, half or full. */
#define DUPLEX_HALF		0x00
#define DUPLEX_FULL		0x01

#define MAX_ADDR_LEN 6
struct rt_macb_eth
{
	/* inherit from ethernet device */
	struct eth_device parent;

	unsigned int		regs;

	unsigned int		rx_tail;
	unsigned int		tx_head;
	unsigned int		tx_tail;
	unsigned int		rx_pending;
	unsigned int		tx_pending;

	void			*rx_buffer;
	void			*tx_buffer;
	struct macb_dma_desc	*rx_ring;
	struct macb_dma_desc	*tx_ring;

	unsigned long		rx_buffer_dma;
	unsigned long		tx_buffer_dma;
	unsigned long		rx_ring_dma;
	unsigned long		tx_ring_dma;

	unsigned int		tx_stop;

	/* interface address info. */
	rt_uint8_t  dev_addr[MAX_ADDR_LEN];		/* hw address	*/
	unsigned short		phy_addr;

	struct rt_semaphore mdio_bus_lock;
	struct rt_semaphore tx_lock;
	struct rt_semaphore rx_lock;
	struct rt_semaphore tx_ack;
	rt_uint32_t  speed;
	rt_uint32_t  duplex;
	rt_uint32_t link;
	struct rt_timer  timer;
};
static struct rt_macb_eth macb_device;

static void macb_tx(struct rt_macb_eth *macb);

static void udelay(rt_uint32_t us)
{
    rt_uint32_t len;
    for (;us > 0; us --)
        for (len = 0; len < 10; len++ );
}

static void rt_macb_isr(int irq, void *param)
{
	struct rt_macb_eth *macb = (struct rt_macb_eth *)param;
	rt_device_t dev = &(macb->parent.parent);
	rt_uint32_t status, rsr, tsr;

	status = macb_readl(macb, ISR);

	while (status) {

		if (status & MACB_RX_INT_FLAGS)
		{
			rsr = macb_readl(macb, RSR);
			macb_writel(macb, RSR, rsr);
			/* a frame has been received */
			eth_device_ready(&(macb_device.parent));
		
		}

		if (status & (MACB_BIT(TCOMP) | MACB_BIT(ISR_TUND) |
			    MACB_BIT(ISR_RLE)))
		{
			macb_tx(macb);
		}

		/*
		 * Link change detection isn't possible with RMII, so we'll
		 * add that if/when we get our hands on a full-blown MII PHY.
		 */

		if (status & MACB_BIT(HRESP))
		{
			/*
			 * TODO: Reset the hardware, and maybe move the printk
			 * to a lower-priority context as well (work queue?)
			 */
			rt_kprintf("%s: DMA bus error: HRESP not OK\n",
			       dev->parent.name);
		}

		status = macb_readl(macb, ISR);
	}


}

static int macb_mdio_write(struct rt_macb_eth *macb, rt_uint8_t reg, rt_uint16_t value)
{
	unsigned long netctl;
	unsigned long netstat;
	unsigned long frame;

	rt_sem_take(&macb->mdio_bus_lock, RT_WAITING_FOREVER);
	netctl = macb_readl(macb, NCR);
	netctl |= MACB_BIT(MPE);
	macb_writel(macb, NCR, netctl);

	frame = (MACB_BF(SOF, 1)
		 | MACB_BF(RW, 1)
		 | MACB_BF(PHYA, macb->phy_addr)
		 | MACB_BF(REGA, reg)
		 | MACB_BF(CODE, 2)
		 | MACB_BF(DATA, value));
	macb_writel(macb, MAN, frame);

	do {
		netstat = macb_readl(macb, NSR);
	} while (!(netstat & MACB_BIT(IDLE)));

	netctl = macb_readl(macb, NCR);
	netctl &= ~MACB_BIT(MPE);
	macb_writel(macb, NCR, netctl);
	rt_sem_release(&macb->mdio_bus_lock);
}

static int macb_mdio_read(struct rt_macb_eth *macb, rt_uint8_t reg)
{
	unsigned long netctl;
	unsigned long netstat;
	unsigned long frame;

	rt_sem_take(&macb->mdio_bus_lock, RT_WAITING_FOREVER);
	netctl = macb_readl(macb, NCR);
	netctl |= MACB_BIT(MPE);
	macb_writel(macb, NCR, netctl);

	frame = (MACB_BF(SOF, 1)
		 | MACB_BF(RW, 2)
		 | MACB_BF(PHYA, macb->phy_addr)
		 | MACB_BF(REGA, reg)
		 | MACB_BF(CODE, 2));
	macb_writel(macb, MAN, frame);

	do {
		netstat = macb_readl(macb, NSR);
	} while (!(netstat & MACB_BIT(IDLE)));

	frame = macb_readl(macb, MAN);

	netctl = macb_readl(macb, NCR);
	netctl &= ~MACB_BIT(MPE);
	macb_writel(macb, NCR, netctl);
	rt_sem_release(&macb->mdio_bus_lock);

	return MACB_BFEXT(DATA, frame);
}

static void macb_phy_reset(rt_device_t dev)
{
	int i;
	rt_uint16_t status, adv;
	struct rt_macb_eth *macb = dev->user_data;;

	adv = ADVERTISE_CSMA | ADVERTISE_ALL;
	macb_mdio_write(macb, MII_ADVERTISE, adv);
	rt_kprintf("%s: Starting autonegotiation...\n", dev->parent.name);
	macb_mdio_write(macb, MII_BMCR, (BMCR_ANENABLE
					 | BMCR_ANRESTART));

	for (i = 0; i < MACB_AUTONEG_TIMEOUT / 100; i++)
	{
		status = macb_mdio_read(macb, MII_BMSR);
		if (status & BMSR_ANEGCOMPLETE)
			break;
		udelay(100);
	}

	if (status & BMSR_ANEGCOMPLETE)
		rt_kprintf("%s: Autonegotiation complete\n", dev->parent.name);
	else
		rt_kprintf("%s: Autonegotiation timed out (status=0x%04x)\n",
		       dev->parent.name, status);
}


static int macb_phy_init(rt_device_t dev)
{
	struct rt_macb_eth *macb = dev->user_data;
	rt_uint32_t ncfgr;
	rt_uint16_t phy_id, status, adv, lpa;
	int media, speed, duplex;
	int i;

	/* Check if the PHY is up to snuff... */
	phy_id = macb_mdio_read(macb, MII_PHYSID1);
	if (phy_id == 0xffff)
	{
		rt_kprintf("%s: No PHY present\n", dev->parent.name);
		return 0;
	}

	status = macb_mdio_read(macb, MII_BMSR);
	if (!(status & BMSR_LSTATUS))
	{
		/* Try to re-negotiate if we don't have link already. */
		macb_phy_reset(dev);

		for (i = 0; i < MACB_LINK_TIMEOUT / 100; i++)
		{
			status = macb_mdio_read(macb, MII_BMSR);
			if (status & BMSR_LSTATUS)
				break;
			udelay(100);
		}
	}

	if (!(status & BMSR_LSTATUS))
	{
		rt_kprintf("%s: link down (status: 0x%04x)\n",
		       dev->parent.name, status);
		return 0;
	}
	else
	{
		adv = macb_mdio_read(macb, MII_ADVERTISE);
		lpa = macb_mdio_read(macb, MII_LPA);
		media = mii_nway_result(lpa & adv);
		speed = (media & (ADVERTISE_100FULL | ADVERTISE_100HALF)
			 ? 1 : 0);
		duplex = (media & ADVERTISE_FULL) ? 1 : 0;
		rt_kprintf("%s: link up, %sMbps %s-duplex (lpa: 0x%04x)\n",
		       dev->parent.name,
		       speed ? "100" : "10",
		       duplex ? "full" : "half",
		       lpa);

		ncfgr = macb_readl(macb, NCFGR);
		ncfgr &= ~(MACB_BIT(SPD) | MACB_BIT(FD));
		if (speed)
			ncfgr |= MACB_BIT(SPD);
		if (duplex)
			ncfgr |= MACB_BIT(FD);
		macb_writel(macb, NCFGR, ncfgr);
		return 1;
	}
}

void macb_update_link(void *param)
{
	struct rt_macb_eth *macb = (struct rt_macb_eth *)param;
	rt_device_t dev = &macb->parent.parent;
	int status, status_change = 0;
	rt_uint32_t link;
	rt_uint32_t media;
	rt_uint16_t adv, lpa;

	/* Do a fake read */
	status = macb_mdio_read(macb, MII_BMSR);
	if (status < 0)
		return;

	/* Read link and autonegotiation status */
	status = macb_mdio_read(macb, MII_BMSR);
	if (status < 0)
		return;
	
	if ((status & BMSR_LSTATUS) == 0)
		link = 0;
	else
		link = 1;

	if (link != macb->link)
	{
		macb->link = link;
		status_change = 1;
	}

	if (status_change)
	{
		if (macb->link)
		{
			adv = macb_mdio_read(macb, MII_ADVERTISE);
			lpa = macb_mdio_read(macb, MII_LPA);
			media = mii_nway_result(lpa & adv);
			macb->speed = (media & (ADVERTISE_100FULL | ADVERTISE_100HALF)
				 ? 100 : 10);
			macb->duplex = (media & ADVERTISE_FULL) ? 1 : 0;
			rt_kprintf("%s: link up (%dMbps/%s-duplex)\n",
					dev->parent.name, macb->speed,
					DUPLEX_FULL == macb->duplex ? "Full":"Half");
			eth_device_linkchange(&macb->parent, RT_TRUE);
		}
		else
		{
			rt_kprintf("%s: link down\n", dev->parent.name);
			eth_device_linkchange(&macb->parent, RT_FALSE);
		}

	}

}

/* RT-Thread Device Interface */
/* initialize the interface */

static rt_err_t rt_macb_init(rt_device_t dev)
{
	struct rt_macb_eth *macb = dev->user_data;
	unsigned long paddr;
	rt_uint32_t hwaddr_bottom;
	rt_uint16_t hwaddr_top;
	int i;

	/*
	 * macb_halt should have been called at some point before now,
	 * so we'll assume the controller is idle.
	 */

	/* initialize DMA descriptors */
	paddr = macb->rx_buffer_dma;
	for (i = 0; i < MACB_RX_RING_SIZE; i++)
	{
		if (i == (MACB_RX_RING_SIZE - 1))
			paddr |= RXADDR_WRAP;
		macb->rx_ring[i].addr = paddr;
		macb->rx_ring[i].ctrl = 0;
		paddr += 128;
	}
	paddr = macb->tx_buffer_dma;
	for (i = 0; i < MACB_TX_RING_SIZE; i++)
	{
		macb->tx_ring[i].addr = paddr;
		if (i == (MACB_TX_RING_SIZE - 1))
			macb->tx_ring[i].ctrl = TXBUF_USED | TXBUF_WRAP;
		else
			macb->tx_ring[i].ctrl = TXBUF_USED;
		paddr += 1536;
	}
	macb->rx_tail = macb->tx_head = macb->tx_tail = 0;

	BD_CACHE_WRITEBACK_INVALIDATE(macb->rx_ring, MACB_RX_RING_SIZE * sizeof(struct macb_dma_desc));
	BD_CACHE_WRITEBACK_INVALIDATE(macb->tx_ring, MACB_TX_RING_SIZE * sizeof(struct macb_dma_desc));
	macb_writel(macb, RBQP, macb->rx_ring_dma);
	macb_writel(macb, TBQP, macb->tx_ring_dma);
	
	/* set hardware address */
	hwaddr_bottom = (*((rt_uint32_t *)macb->dev_addr));
	macb_writel(macb, SA1B, hwaddr_bottom);
	hwaddr_top = (*((rt_uint16_t *)(macb->dev_addr + 4)));
	macb_writel(macb, SA1T, hwaddr_top);

	
	/* choose RMII or MII mode. This depends on the board */
#ifdef CONFIG_RMII
	macb_writel(macb, USRIO, MACB_BIT(RMII) | MACB_BIT(CLKEN));
#else
	macb_writel(macb, USRIO, MACB_BIT(CLKEN));
#endif /* CONFIG_RMII */

	if (!macb_phy_init(dev))
		return -RT_ERROR;

	/* Enable TX and RX */
	macb_writel(macb, NCR, MACB_BIT(TE) | MACB_BIT(RE) | MACB_BIT(MPE));
	
	/* Enable interrupts */
	macb_writel(macb, IER, (MACB_BIT(RCOMP)
			      | MACB_BIT(RXUBR)
			      | MACB_BIT(ISR_TUND)
			      | MACB_BIT(ISR_RLE)
			      | MACB_BIT(TXERR)
			      | MACB_BIT(TCOMP)
			      | MACB_BIT(ISR_ROVR)
			      | MACB_BIT(HRESP)));
	
	/* instal interrupt */
	rt_hw_interrupt_install(AT91SAM9260_ID_EMAC, rt_macb_isr, 
							(void *)macb, "emac");
	rt_hw_interrupt_umask(AT91SAM9260_ID_EMAC);

	rt_timer_init(&macb->timer, "link_timer", 
		macb_update_link, 
		(void *)macb, 
		RT_TICK_PER_SECOND, 
		RT_TIMER_FLAG_PERIODIC);

	rt_timer_start(&macb->timer);
	
	return RT_EOK;
}

static rt_err_t rt_macb_open(rt_device_t dev, rt_uint16_t oflag)
{
	return RT_EOK;
}

static rt_err_t rt_macb_close(rt_device_t dev)
{
	return RT_EOK;
}

static rt_size_t rt_macb_read(rt_device_t dev, rt_off_t pos, void* buffer, rt_size_t size)
{
	rt_set_errno(-RT_ENOSYS);
	return 0;
}

static rt_size_t rt_macb_write (rt_device_t dev, rt_off_t pos, const void* buffer, rt_size_t size)
{
	rt_set_errno(-RT_ENOSYS);
	return 0;
}

static rt_err_t rt_macb_control(rt_device_t dev, int cmd, void *args)
{
	switch(cmd)
	{
	case NIOCTL_GADDR:
		/* get mac address */
		if(args) rt_memcpy(args, macb_device.dev_addr, 6);
		else return -RT_ERROR;
		break;

	default :
		break;
	}

	return RT_EOK;
}

static void macb_tx(struct rt_macb_eth *macb)
{
	unsigned int tail;
	unsigned int head;
	rt_uint32_t status;

	status = macb_readl(macb, TSR);
	macb_writel(macb, TSR, status);

	/*rt_kprintf("macb_tx status = %02lx\n",
		(unsigned long)status);*/

	if (status & (MACB_BIT(UND) | MACB_BIT(TSR_RLE)))
	{
		int i;
		rt_kprintf("%s: TX %s, resetting buffers\n",
			macb->parent.parent.parent.name, status & MACB_BIT(UND) ?
			"underrun" : "retry limit exceeded");

		/* Transfer ongoing, disable transmitter, to avoid confusion */
		if (status & MACB_BIT(TGO))
			macb_writel(macb, NCR, macb_readl(macb, NCR) & ~MACB_BIT(TE));

		head = macb->tx_head;

		/*Mark all the buffer as used to avoid sending a lost buffer*/
		for (i = 0; i < MACB_TX_RING_SIZE; i++)
			macb->tx_ring[i].ctrl = MACB_BIT(TX_USED);

		/* free transmit buffer in upper layer*/

		macb->tx_head = macb->tx_tail = 0;

		/* Enable the transmitter again */
		if (status & MACB_BIT(TGO))
			macb_writel(macb, NCR, macb_readl(macb, NCR) | MACB_BIT(TE));
	}

	if (!(status & MACB_BIT(COMP)))
		/*
		 * This may happen when a buffer becomes complete
		 * between reading the ISR and scanning the
		 * descriptors.  Nothing to worry about.
		 */
		return;

	head = macb->tx_head;
	for (tail = macb->tx_tail; tail != head; tail = NEXT_TX(tail))
	{
		rt_uint32_t bufstat;

		bufstat = macb->tx_ring[tail].ctrl;

		if (!(bufstat & MACB_BIT(TX_USED)))
			break;
	}

	macb->tx_tail = tail;
	if ((macb->tx_stop == 1) &&
	    TX_BUFFS_AVAIL(macb) > MACB_TX_WAKEUP_THRESH)
		rt_sem_release(&macb->tx_ack);
}


/* ethernet device interface */
/* transmit packet. */
rt_err_t rt_macb_tx( rt_device_t dev, struct pbuf* p)
{
	unsigned long ctrl;
	struct pbuf* q;
	rt_uint8_t* bufptr;
	rt_uint32_t mapping;
	struct rt_macb_eth *macb = dev->user_data;
	unsigned int tx_head = macb->tx_head;

	rt_sem_take(&macb->tx_lock, RT_WAITING_FOREVER);
	if (TX_BUFFS_AVAIL(macb) < 1)
	{
		rt_sem_release(&macb->tx_lock);
		rt_kprintf("Tx Ring full!\n");
		rt_kprintf("tx_head = %u, tx_tail = %u\n",
			macb->tx_head, macb->tx_tail);
		return -RT_ERROR;
	}

	macb->tx_stop = 0;

	ctrl = p->tot_len & TXBUF_FRMLEN_MASK;
	ctrl |= TXBUF_FRAME_END;
	if (tx_head == (MACB_TX_RING_SIZE - 1))
	{
		ctrl |= TXBUF_WRAP;
	}
#if defined(MACB_TX_SRAM)
	bufptr = macb->tx_buffer + tx_head * 1536;
#else
	mapping = (unsigned long)macb->tx_buffer + tx_head * 1536;
	bufptr = (rt_uint8_t *)mapping;
#endif

	for (q = p; q != NULL; q = q->next)
	{
		memcpy(bufptr, q->payload, q->len);
		bufptr += q->len;
	}
#if !defined(MACB_TX_SRAM)
	EMAC_CACHE_WRITEBACK(mapping, p->tot_len);
#endif
	macb->tx_ring[tx_head].ctrl = ctrl;
	BD_CACHE_WRITEBACK_INVALIDATE(&macb->tx_ring[tx_head], sizeof(struct macb_dma_desc));
	tx_head = NEXT_TX(tx_head);
	macb->tx_head = tx_head;
	macb_writel(macb, NCR, macb_readl(macb, NCR) | MACB_BIT(TSTART));
	macb_writel(macb, NCR, macb_readl(macb, NCR) | MACB_BIT(TSTART));

	if (TX_BUFFS_AVAIL(macb) < 1)
	{
		macb->tx_stop = 1;
		rt_sem_take(&macb->tx_ack, RT_WAITING_FOREVER);
	}
	rt_sem_release(&macb->tx_lock);

	return RT_EOK;
}

static void reclaim_rx_buffers(struct rt_macb_eth *macb,
			       unsigned int new_tail)
{
	unsigned int i;

	i = macb->rx_tail;
	while (i > new_tail)
	{
		macb->rx_ring[i].addr &= ~RXADDR_USED;
		i++;
		if (i > MACB_RX_RING_SIZE)
			i = 0;
	}

	while (i < new_tail)
	{
		macb->rx_ring[i].addr &= ~RXADDR_USED;
		i++;
	}

	macb->rx_tail = new_tail;
}

/* reception packet. */
struct pbuf *rt_macb_rx(rt_device_t dev)
{
	struct rt_macb_eth *macb = dev->user_data;
	struct pbuf* p = RT_NULL;
	rt_uint32_t len;
	unsigned int rx_tail = macb->rx_tail;
	void *buffer;
	int wrapped = 0;
	rt_uint32_t status;

	rt_sem_take(&macb->rx_lock, RT_WAITING_FOREVER);
	for (;;)
	{
		if (!(macb->rx_ring[rx_tail].addr & RXADDR_USED))
			break;

		status = macb->rx_ring[rx_tail].ctrl;
		if (status & RXBUF_FRAME_START)
		{
			if (rx_tail != macb->rx_tail)
				reclaim_rx_buffers(macb, rx_tail);
			wrapped = 0;
		}

		if (status & RXBUF_FRAME_END)
		{
			buffer = (void *)((unsigned int)macb->rx_buffer + 128 * macb->rx_tail);
			len = status & RXBUF_FRMLEN_MASK;
			p = pbuf_alloc(PBUF_LINK, len, PBUF_RAM);
			if (!p)
			{
				rt_kprintf("alloc pbuf failed\n");
				break;
			}
			if (wrapped)
			{
				unsigned int headlen, taillen;

				headlen = 128 * (MACB_RX_RING_SIZE
						 - macb->rx_tail);
				taillen = len - headlen;
				EMAC_CACHE_INVALIDATE(buffer, headlen);
				EMAC_CACHE_INVALIDATE(macb->rx_buffer, taillen);
				memcpy((void *)p->payload, buffer, headlen);
				memcpy((void *)((unsigned int)p->payload + headlen),
				       macb->rx_buffer, taillen);
			}
			else
			{
				EMAC_CACHE_INVALIDATE(buffer, len);
				memcpy((void *)p->payload, buffer, p->len);
			}
			
			if (++rx_tail >= MACB_RX_RING_SIZE)
				rx_tail = 0;
			reclaim_rx_buffers(macb, rx_tail);
			break;
		}
		else
		{
			if (++rx_tail >= MACB_RX_RING_SIZE)
			{
				wrapped = 1;
				rx_tail = 0;
			}
		}
	}

	rt_sem_release(&macb->rx_lock);

	return p;
}

void macb_gpio_init()
{
	/* Pins used for MII and RMII */
	at91_sys_write(AT91_PIOA + PIO_PDR, (1 << 19)|(1 << 17)|(1 << 14)|(1 << 15)|(1 << 18)|(1 << 16)|(1 << 12)|(1 << 13)|(1 << 21)|(1 << 20));
	at91_sys_write(AT91_PIOA + PIO_ASR, (1 << 19)|(1 << 17)|(1 << 14)|(1 << 15)|(1 << 18)|(1 << 16)|(1 << 12)|(1 << 13)|(1 << 21)|(1 << 20));

#ifndef GONFIG_RMII
	at91_sys_write(AT91_PIOA + PIO_PDR, (1 << 22)|(1 << 23)|(1 << 24)|(1 << 25)|(1 << 26)|(1 << 27)|(1 << 28)|(1 << 29));
	at91_sys_write(AT91_PIOA + PIO_ASR, (1 << 22)|(1 << 23)|(1 << 24)|(1 << 25)|(1 << 26)|(1 << 27)|(1 << 28)|(1 << 29));
#endif
}

rt_err_t macb_initialize()
{
	struct rt_macb_eth *macb = &macb_device;
	unsigned long macb_hz;
	rt_uint32_t ncfgr;
	
#if defined(MACB_TX_SRAM)
	macb->tx_ring_dma = AT91SAM9260_SRAM0_BASE;
	macb->tx_ring = (struct macb_dma_desc *)AT91SAM9260_SRAM0_VIRT_BASE;
	macb->tx_buffer = (char *) macb->tx_ring + TX_RING_BYTES;
	macb->tx_buffer_dma = macb->tx_ring_dma + TX_RING_BYTES;
#else
	macb->tx_ring = rt_malloc(MACB_RX_RING_SIZE * sizeof(struct macb_dma_desc));
	if (macb->tx_ring == RT_NULL)
		goto err1;
	EMAC_CACHE_INVALIDATE(macb->tx_ring, MACB_TX_RING_SIZE * sizeof(struct macb_dma_desc));
	macb->tx_ring_dma = emac_virt_to_phys((unsigned long)macb->tx_ring);
	macb->tx_ring = (struct macb_dma_desc *)MMU_NOCACHE_ADDR((unsigned long)macb->tx_ring);
	macb->tx_buffer = rt_malloc(MACB_TX_BUFFER_SIZE);
	if (macb->tx_buffer == RT_NULL)
		goto err2;
	macb->tx_buffer_dma = emac_virt_to_phys((unsigned long)macb->tx_buffer);
#endif

	macb->rx_ring = rt_malloc(MACB_RX_RING_SIZE * sizeof(struct macb_dma_desc));
	if (macb->rx_ring == RT_NULL)
		goto err3;
	EMAC_CACHE_INVALIDATE(macb->rx_ring, MACB_RX_RING_SIZE * sizeof(struct macb_dma_desc));
	macb->rx_ring_dma = emac_virt_to_phys((unsigned long)macb->rx_ring);
	macb->rx_ring = (struct macb_dma_desc *)MMU_NOCACHE_ADDR((unsigned long)macb->rx_ring);
	macb->rx_buffer = rt_malloc(MACB_RX_BUFFER_SIZE);
	if (macb->rx_buffer == RT_NULL)
		goto err4;
	macb->rx_buffer_dma = emac_virt_to_phys((unsigned long)macb->rx_buffer);

	macb->tx_pending = DEF_TX_RING_PENDING;

	macb->regs = AT91SAM9260_BASE_EMAC;
	macb->phy_addr = 0x00;
	
	/*
	 * Do some basic initialization so that we at least can talk
	 * to the PHY
	 */
	macb_hz = clk_get_rate(clk_get("mck"));
	if (macb_hz < 20000000)
		ncfgr = MACB_BF(CLK, MACB_CLK_DIV8);
	else if (macb_hz < 40000000)
		ncfgr = MACB_BF(CLK, MACB_CLK_DIV16);
	else if (macb_hz < 80000000)
		ncfgr = MACB_BF(CLK, MACB_CLK_DIV32);
	else
		ncfgr = MACB_BF(CLK, MACB_CLK_DIV64);

	macb_writel(macb, NCFGR, ncfgr);

	macb->link = 0;

	return RT_EOK;

err4:
	rt_free(macb->rx_ring);
	macb->rx_ring = RT_NULL;
err3:
#if !defined(MACB_TX_SRAM)
	rt_free(macb->tx_buffer);
	macb->tx_buffer = RT_NULL;
err2:
	rt_free(macb->tx_ring);
	macb->tx_ring = RT_NULL;
err1:
#endif
	return -RT_ENOMEM;
}

int rt_hw_macb_init(void)
{
	rt_err_t ret;
	at91_sys_write(AT91_PMC + AT91_PMC_PCER, 1 << AT91SAM9260_ID_EMAC); //enable macb clock
	macb_gpio_init();
	rt_memset(&macb_device, 0, sizeof(macb_device));
	ret = macb_initialize();
	if (ret != RT_EOK)
	{
		rt_kprintf("AT91 EMAC initialized failed\n");
		return;
	}
	rt_sem_init(&macb_device.tx_ack, "tx_ack", 0, RT_IPC_FLAG_FIFO);
	rt_sem_init(&macb_device.tx_lock, "tx_lock", 1, RT_IPC_FLAG_FIFO);
	rt_sem_init(&macb_device.rx_lock, "rx_lock", 1, RT_IPC_FLAG_FIFO);

	macb_device.dev_addr[0] = 0x00;
	macb_device.dev_addr[1] = 0x60;
	macb_device.dev_addr[2] = 0x6E;
	macb_device.dev_addr[3] = 0x11;
	macb_device.dev_addr[4] = 0x22;
	macb_device.dev_addr[5] = 0x33;
	
	macb_device.parent.parent.init       = rt_macb_init;
	macb_device.parent.parent.open       = rt_macb_open;
	macb_device.parent.parent.close      = rt_macb_close;
	macb_device.parent.parent.read       = rt_macb_read;
	macb_device.parent.parent.write      = rt_macb_write;
	macb_device.parent.parent.control    = rt_macb_control;
	macb_device.parent.parent.user_data  = &macb_device;

	macb_device.parent.eth_rx     = rt_macb_rx;
	macb_device.parent.eth_tx     = rt_macb_tx;

	rt_sem_init(&macb_device.mdio_bus_lock, "mdio_bus_lock", 1, RT_IPC_FLAG_FIFO);

	eth_device_init(&(macb_device.parent), "e0");

	return 0;
}

INIT_DEVICE_EXPORT(rt_hw_macb_init);