Save sram context after changing MPU, DSP or core clocks

[linux-ginger.git] / drivers / net / macb.c

/*
 * Atmel MACB Ethernet Controller driver
 *
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/phy.h>

#include <mach/board.h>
#include <mach/cpu.h>

#include "macb.h"

#define RX_BUFFER_SIZE          128
#define RX_RING_SIZE            512
#define RX_RING_BYTES           (sizeof(struct dma_desc) * RX_RING_SIZE)

/* Make the IP header word-aligned (the ethernet header is 14 bytes) */
#define RX_OFFSET               2

#define TX_RING_SIZE            128
#define DEF_TX_RING_PENDING     (TX_RING_SIZE - 1)
#define TX_RING_BYTES           (sizeof(struct dma_desc) * TX_RING_SIZE)

#define TX_RING_GAP(bp)                                         \
        (TX_RING_SIZE - (bp)->tx_pending)
#define TX_BUFFS_AVAIL(bp)                                      \
        (((bp)->tx_tail <= (bp)->tx_head) ?                     \
         (bp)->tx_tail + (bp)->tx_pending - (bp)->tx_head :     \
         (bp)->tx_tail - (bp)->tx_head - TX_RING_GAP(bp))
#define NEXT_TX(n)              (((n) + 1) & (TX_RING_SIZE - 1))

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

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

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

static void __macb_set_hwaddr(struct macb *bp)
{
        u32 bottom;
        u16 top;

        bottom = cpu_to_le32(*((u32 *)bp->dev->dev_addr));
        macb_writel(bp, SA1B, bottom);
        top = cpu_to_le16(*((u16 *)(bp->dev->dev_addr + 4)));
        macb_writel(bp, SA1T, top);
}

static void __init macb_get_hwaddr(struct macb *bp)
{
        u32 bottom;
        u16 top;
        u8 addr[6];

        bottom = macb_readl(bp, SA1B);
        top = macb_readl(bp, SA1T);

        addr[0] = bottom & 0xff;
        addr[1] = (bottom >> 8) & 0xff;
        addr[2] = (bottom >> 16) & 0xff;
        addr[3] = (bottom >> 24) & 0xff;
        addr[4] = top & 0xff;
        addr[5] = (top >> 8) & 0xff;

        if (is_valid_ether_addr(addr)) {
                memcpy(bp->dev->dev_addr, addr, sizeof(addr));
        } else {
                dev_info(&bp->pdev->dev, "invalid hw address, using random\n");
                random_ether_addr(bp->dev->dev_addr);
        }
}

static int macb_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
        struct macb *bp = bus->priv;
        int value;

        macb_writel(bp, MAN, (MACB_BF(SOF, MACB_MAN_SOF)
                              | MACB_BF(RW, MACB_MAN_READ)
                              | MACB_BF(PHYA, mii_id)
                              | MACB_BF(REGA, regnum)
                              | MACB_BF(CODE, MACB_MAN_CODE)));

        /* wait for end of transfer */
        while (!MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
                cpu_relax();

        value = MACB_BFEXT(DATA, macb_readl(bp, MAN));

        return value;
}

static int macb_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
                           u16 value)
{
        struct macb *bp = bus->priv;

        macb_writel(bp, MAN, (MACB_BF(SOF, MACB_MAN_SOF)
                              | MACB_BF(RW, MACB_MAN_WRITE)
                              | MACB_BF(PHYA, mii_id)
                              | MACB_BF(REGA, regnum)
                              | MACB_BF(CODE, MACB_MAN_CODE)
                              | MACB_BF(DATA, value)));

        /* wait for end of transfer */
        while (!MACB_BFEXT(IDLE, macb_readl(bp, NSR)))
                cpu_relax();

        return 0;
}

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

static void macb_handle_link_change(struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        struct phy_device *phydev = bp->phy_dev;
        unsigned long flags;

        int status_change = 0;

        spin_lock_irqsave(&bp->lock, flags);

        if (phydev->link) {
                if ((bp->speed != phydev->speed) ||
                    (bp->duplex != phydev->duplex)) {
                        u32 reg;

                        reg = macb_readl(bp, NCFGR);
                        reg &= ~(MACB_BIT(SPD) | MACB_BIT(FD));

                        if (phydev->duplex)
                                reg |= MACB_BIT(FD);
                        if (phydev->speed == SPEED_100)
                                reg |= MACB_BIT(SPD);

                        macb_writel(bp, NCFGR, reg);

                        bp->speed = phydev->speed;
                        bp->duplex = phydev->duplex;
                        status_change = 1;
                }
        }

        if (phydev->link != bp->link) {
                if (!phydev->link) {
                        bp->speed = 0;
                        bp->duplex = -1;
                }
                bp->link = phydev->link;

                status_change = 1;
        }

        spin_unlock_irqrestore(&bp->lock, flags);

        if (status_change) {
                if (phydev->link)
                        printk(KERN_INFO "%s: link up (%d/%s)\n",
                               dev->name, phydev->speed,
                               DUPLEX_FULL == phydev->duplex ? "Full":"Half");
                else
                        printk(KERN_INFO "%s: link down\n", dev->name);
        }
}

/* based on au1000_eth. c*/
static int macb_mii_probe(struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        struct phy_device *phydev = NULL;
        struct eth_platform_data *pdata;
        int phy_addr;

        /* find the first phy */
        for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++) {
                if (bp->mii_bus->phy_map[phy_addr]) {
                        phydev = bp->mii_bus->phy_map[phy_addr];
                        break;
                }
        }

        if (!phydev) {
                printk (KERN_ERR "%s: no PHY found\n", dev->name);
                return -1;
        }

        pdata = bp->pdev->dev.platform_data;
        /* TODO : add pin_irq */

        /* attach the mac to the phy */
        if (pdata && pdata->is_rmii) {
                phydev = phy_connect(dev, dev_name(&phydev->dev),
                        &macb_handle_link_change, 0, PHY_INTERFACE_MODE_RMII);
        } else {
                phydev = phy_connect(dev, dev_name(&phydev->dev),
                        &macb_handle_link_change, 0, PHY_INTERFACE_MODE_MII);
        }

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

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

        phydev->advertising = phydev->supported;

        bp->link = 0;
        bp->speed = 0;
        bp->duplex = -1;
        bp->phy_dev = phydev;

        return 0;
}

static int macb_mii_init(struct macb *bp)
{
        struct eth_platform_data *pdata;
        int err = -ENXIO, i;

        /* Enable management port */
        macb_writel(bp, NCR, MACB_BIT(MPE));

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

        bp->mii_bus->name = "MACB_mii_bus";
        bp->mii_bus->read = &macb_mdio_read;
        bp->mii_bus->write = &macb_mdio_write;
        bp->mii_bus->reset = &macb_mdio_reset;
        snprintf(bp->mii_bus->id, MII_BUS_ID_SIZE, "%x", bp->pdev->id);
        bp->mii_bus->priv = bp;
        bp->mii_bus->parent = &bp->dev->dev;
        pdata = bp->pdev->dev.platform_data;

        if (pdata)
                bp->mii_bus->phy_mask = pdata->phy_mask;

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

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

        platform_set_drvdata(bp->dev, bp->mii_bus);

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

        if (macb_mii_probe(bp->dev) != 0) {
                goto err_out_unregister_bus;
        }

        return 0;

err_out_unregister_bus:
        mdiobus_unregister(bp->mii_bus);
err_out_free_mdio_irq:
        kfree(bp->mii_bus->irq);
err_out_free_mdiobus:
        mdiobus_free(bp->mii_bus);
err_out:
        return err;
}

static void macb_update_stats(struct macb *bp)
{
        u32 __iomem *reg = bp->regs + MACB_PFR;
        u32 *p = &bp->hw_stats.rx_pause_frames;
        u32 *end = &bp->hw_stats.tx_pause_frames + 1;

        WARN_ON((unsigned long)(end - p - 1) != (MACB_TPF - MACB_PFR) / 4);

        for(; p < end; p++, reg++)
                *p += __raw_readl(reg);
}

static void macb_tx(struct macb *bp)
{
        unsigned int tail;
        unsigned int head;
        u32 status;

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

        dev_dbg(&bp->pdev->dev, "macb_tx status = %02lx\n",
                (unsigned long)status);

        if (status & (MACB_BIT(UND) | MACB_BIT(TSR_RLE))) {
                int i;
                printk(KERN_ERR "%s: TX %s, resetting buffers\n",
                        bp->dev->name, status & MACB_BIT(UND) ?
                        "underrun" : "retry limit exceeded");

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

                head = bp->tx_head;

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

                /* free transmit buffer in upper layer*/
                for (tail = bp->tx_tail; tail != head; tail = NEXT_TX(tail)) {
                        struct ring_info *rp = &bp->tx_skb[tail];
                        struct sk_buff *skb = rp->skb;

                        BUG_ON(skb == NULL);

                        rmb();

                        dma_unmap_single(&bp->pdev->dev, rp->mapping, skb->len,
                                                         DMA_TO_DEVICE);
                        rp->skb = NULL;
                        dev_kfree_skb_irq(skb);
                }

                bp->tx_head = bp->tx_tail = 0;

                /* Enable the transmitter again */
                if (status & MACB_BIT(TGO))
                        macb_writel(bp, NCR, macb_readl(bp, 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 = bp->tx_head;
        for (tail = bp->tx_tail; tail != head; tail = NEXT_TX(tail)) {
                struct ring_info *rp = &bp->tx_skb[tail];
                struct sk_buff *skb = rp->skb;
                u32 bufstat;

                BUG_ON(skb == NULL);

                rmb();
                bufstat = bp->tx_ring[tail].ctrl;

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

                dev_dbg(&bp->pdev->dev, "skb %u (data %p) TX complete\n",
                        tail, skb->data);
                dma_unmap_single(&bp->pdev->dev, rp->mapping, skb->len,
                                 DMA_TO_DEVICE);
                bp->stats.tx_packets++;
                bp->stats.tx_bytes += skb->len;
                rp->skb = NULL;
                dev_kfree_skb_irq(skb);
        }

        bp->tx_tail = tail;
        if (netif_queue_stopped(bp->dev) &&
            TX_BUFFS_AVAIL(bp) > MACB_TX_WAKEUP_THRESH)
                netif_wake_queue(bp->dev);
}

static int macb_rx_frame(struct macb *bp, unsigned int first_frag,
                         unsigned int last_frag)
{
        unsigned int len;
        unsigned int frag;
        unsigned int offset = 0;
        struct sk_buff *skb;

        len = MACB_BFEXT(RX_FRMLEN, bp->rx_ring[last_frag].ctrl);

        dev_dbg(&bp->pdev->dev, "macb_rx_frame frags %u - %u (len %u)\n",
                first_frag, last_frag, len);

        skb = dev_alloc_skb(len + RX_OFFSET);
        if (!skb) {
                bp->stats.rx_dropped++;
                for (frag = first_frag; ; frag = NEXT_RX(frag)) {
                        bp->rx_ring[frag].addr &= ~MACB_BIT(RX_USED);
                        if (frag == last_frag)
                                break;
                }
                wmb();
                return 1;
        }

        skb_reserve(skb, RX_OFFSET);
        skb->ip_summed = CHECKSUM_NONE;
        skb_put(skb, len);

        for (frag = first_frag; ; frag = NEXT_RX(frag)) {
                unsigned int frag_len = RX_BUFFER_SIZE;

                if (offset + frag_len > len) {
                        BUG_ON(frag != last_frag);
                        frag_len = len - offset;
                }
                skb_copy_to_linear_data_offset(skb, offset,
                                               (bp->rx_buffers +
                                                (RX_BUFFER_SIZE * frag)),
                                               frag_len);
                offset += RX_BUFFER_SIZE;
                bp->rx_ring[frag].addr &= ~MACB_BIT(RX_USED);
                wmb();

                if (frag == last_frag)
                        break;
        }

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

        bp->stats.rx_packets++;
        bp->stats.rx_bytes += len;
        dev_dbg(&bp->pdev->dev, "received skb of length %u, csum: %08x\n",
                skb->len, skb->csum);
        netif_receive_skb(skb);

        return 0;
}

/* Mark DMA descriptors from begin up to and not including end as unused */
static void discard_partial_frame(struct macb *bp, unsigned int begin,
                                  unsigned int end)
{
        unsigned int frag;

        for (frag = begin; frag != end; frag = NEXT_RX(frag))
                bp->rx_ring[frag].addr &= ~MACB_BIT(RX_USED);
        wmb();

        /*
         * When this happens, the hardware stats registers for
         * whatever caused this is updated, so we don't have to record
         * anything.
         */
}

static int macb_rx(struct macb *bp, int budget)
{
        int received = 0;
        unsigned int tail = bp->rx_tail;
        int first_frag = -1;

        for (; budget > 0; tail = NEXT_RX(tail)) {
                u32 addr, ctrl;

                rmb();
                addr = bp->rx_ring[tail].addr;
                ctrl = bp->rx_ring[tail].ctrl;

                if (!(addr & MACB_BIT(RX_USED)))
                        break;

                if (ctrl & MACB_BIT(RX_SOF)) {
                        if (first_frag != -1)
                                discard_partial_frame(bp, first_frag, tail);
                        first_frag = tail;
                }

                if (ctrl & MACB_BIT(RX_EOF)) {
                        int dropped;
                        BUG_ON(first_frag == -1);

                        dropped = macb_rx_frame(bp, first_frag, tail);
                        first_frag = -1;
                        if (!dropped) {
                                received++;
                                budget--;
                        }
                }
        }

        if (first_frag != -1)
                bp->rx_tail = first_frag;
        else
                bp->rx_tail = tail;

        return received;
}

static int macb_poll(struct napi_struct *napi, int budget)
{
        struct macb *bp = container_of(napi, struct macb, napi);
        int work_done;
        u32 status;

        status = macb_readl(bp, RSR);
        macb_writel(bp, RSR, status);

        work_done = 0;

        dev_dbg(&bp->pdev->dev, "poll: status = %08lx, budget = %d\n",
                (unsigned long)status, budget);

        work_done = macb_rx(bp, budget);
        if (work_done < budget)
                napi_complete(napi);

        /*
         * We've done what we can to clean the buffers. Make sure we
         * get notified when new packets arrive.
         */
        macb_writel(bp, IER, MACB_RX_INT_FLAGS);

        /* TODO: Handle errors */

        return work_done;
}

static irqreturn_t macb_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct macb *bp = netdev_priv(dev);
        u32 status;

        status = macb_readl(bp, ISR);

        if (unlikely(!status))
                return IRQ_NONE;

        spin_lock(&bp->lock);

        while (status) {
                /* close possible race with dev_close */
                if (unlikely(!netif_running(dev))) {
                        macb_writel(bp, IDR, ~0UL);
                        break;
                }

                if (status & MACB_RX_INT_FLAGS) {
                        if (napi_schedule_prep(&bp->napi)) {
                                /*
                                 * There's no point taking any more interrupts
                                 * until we have processed the buffers
                                 */
                                macb_writel(bp, IDR, MACB_RX_INT_FLAGS);
                                dev_dbg(&bp->pdev->dev,
                                        "scheduling RX softirq\n");
                                __napi_schedule(&bp->napi);
                        }
                }

                if (status & (MACB_BIT(TCOMP) | MACB_BIT(ISR_TUND) |
                            MACB_BIT(ISR_RLE)))
                        macb_tx(bp);

                /*
                 * 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?)
                         */
                        printk(KERN_ERR "%s: DMA bus error: HRESP not OK\n",
                               dev->name);
                }

                status = macb_readl(bp, ISR);
        }

        spin_unlock(&bp->lock);

        return IRQ_HANDLED;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/*
 * Polling receive - used by netconsole and other diagnostic tools
 * to allow network i/o with interrupts disabled.
 */
static void macb_poll_controller(struct net_device *dev)
{
        unsigned long flags;

        local_irq_save(flags);
        macb_interrupt(dev->irq, dev);
        local_irq_restore(flags);
}
#endif

static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        dma_addr_t mapping;
        unsigned int len, entry;
        u32 ctrl;
        unsigned long flags;

#ifdef DEBUG
        int i;
        dev_dbg(&bp->pdev->dev,
                "start_xmit: len %u head %p data %p tail %p end %p\n",
                skb->len, skb->head, skb->data,
                skb_tail_pointer(skb), skb_end_pointer(skb));
        dev_dbg(&bp->pdev->dev,
                "data:");
        for (i = 0; i < 16; i++)
                printk(" %02x", (unsigned int)skb->data[i]);
        printk("\n");
#endif

        len = skb->len;
        spin_lock_irqsave(&bp->lock, flags);

        /* This is a hard error, log it. */
        if (TX_BUFFS_AVAIL(bp) < 1) {
                netif_stop_queue(dev);
                spin_unlock_irqrestore(&bp->lock, flags);
                dev_err(&bp->pdev->dev,
                        "BUG! Tx Ring full when queue awake!\n");
                dev_dbg(&bp->pdev->dev, "tx_head = %u, tx_tail = %u\n",
                        bp->tx_head, bp->tx_tail);
                return NETDEV_TX_BUSY;
        }

        entry = bp->tx_head;
        dev_dbg(&bp->pdev->dev, "Allocated ring entry %u\n", entry);
        mapping = dma_map_single(&bp->pdev->dev, skb->data,
                                 len, DMA_TO_DEVICE);
        bp->tx_skb[entry].skb = skb;
        bp->tx_skb[entry].mapping = mapping;
        dev_dbg(&bp->pdev->dev, "Mapped skb data %p to DMA addr %08lx\n",
                skb->data, (unsigned long)mapping);

        ctrl = MACB_BF(TX_FRMLEN, len);
        ctrl |= MACB_BIT(TX_LAST);
        if (entry == (TX_RING_SIZE - 1))
                ctrl |= MACB_BIT(TX_WRAP);

        bp->tx_ring[entry].addr = mapping;
        bp->tx_ring[entry].ctrl = ctrl;
        wmb();

        entry = NEXT_TX(entry);
        bp->tx_head = entry;

        macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART));

        if (TX_BUFFS_AVAIL(bp) < 1)
                netif_stop_queue(dev);

        spin_unlock_irqrestore(&bp->lock, flags);

        dev->trans_start = jiffies;

        return NETDEV_TX_OK;
}

static void macb_free_consistent(struct macb *bp)
{
        if (bp->tx_skb) {
                kfree(bp->tx_skb);
                bp->tx_skb = NULL;
        }
        if (bp->rx_ring) {
                dma_free_coherent(&bp->pdev->dev, RX_RING_BYTES,
                                  bp->rx_ring, bp->rx_ring_dma);
                bp->rx_ring = NULL;
        }
        if (bp->tx_ring) {
                dma_free_coherent(&bp->pdev->dev, TX_RING_BYTES,
                                  bp->tx_ring, bp->tx_ring_dma);
                bp->tx_ring = NULL;
        }
        if (bp->rx_buffers) {
                dma_free_coherent(&bp->pdev->dev,
                                  RX_RING_SIZE * RX_BUFFER_SIZE,
                                  bp->rx_buffers, bp->rx_buffers_dma);
                bp->rx_buffers = NULL;
        }
}

static int macb_alloc_consistent(struct macb *bp)
{
        int size;

        size = TX_RING_SIZE * sizeof(struct ring_info);
        bp->tx_skb = kmalloc(size, GFP_KERNEL);
        if (!bp->tx_skb)
                goto out_err;

        size = RX_RING_BYTES;
        bp->rx_ring = dma_alloc_coherent(&bp->pdev->dev, size,
                                         &bp->rx_ring_dma, GFP_KERNEL);
        if (!bp->rx_ring)
                goto out_err;
        dev_dbg(&bp->pdev->dev,
                "Allocated RX ring of %d bytes at %08lx (mapped %p)\n",
                size, (unsigned long)bp->rx_ring_dma, bp->rx_ring);

        size = TX_RING_BYTES;
        bp->tx_ring = dma_alloc_coherent(&bp->pdev->dev, size,
                                         &bp->tx_ring_dma, GFP_KERNEL);
        if (!bp->tx_ring)
                goto out_err;
        dev_dbg(&bp->pdev->dev,
                "Allocated TX ring of %d bytes at %08lx (mapped %p)\n",
                size, (unsigned long)bp->tx_ring_dma, bp->tx_ring);

        size = RX_RING_SIZE * RX_BUFFER_SIZE;
        bp->rx_buffers = dma_alloc_coherent(&bp->pdev->dev, size,
                                            &bp->rx_buffers_dma, GFP_KERNEL);
        if (!bp->rx_buffers)
                goto out_err;
        dev_dbg(&bp->pdev->dev,
                "Allocated RX buffers of %d bytes at %08lx (mapped %p)\n",
                size, (unsigned long)bp->rx_buffers_dma, bp->rx_buffers);

        return 0;

out_err:
        macb_free_consistent(bp);
        return -ENOMEM;
}

static void macb_init_rings(struct macb *bp)
{
        int i;
        dma_addr_t addr;

        addr = bp->rx_buffers_dma;
        for (i = 0; i < RX_RING_SIZE; i++) {
                bp->rx_ring[i].addr = addr;
                bp->rx_ring[i].ctrl = 0;
                addr += RX_BUFFER_SIZE;
        }
        bp->rx_ring[RX_RING_SIZE - 1].addr |= MACB_BIT(RX_WRAP);

        for (i = 0; i < TX_RING_SIZE; i++) {
                bp->tx_ring[i].addr = 0;
                bp->tx_ring[i].ctrl = MACB_BIT(TX_USED);
        }
        bp->tx_ring[TX_RING_SIZE - 1].ctrl |= MACB_BIT(TX_WRAP);

        bp->rx_tail = bp->tx_head = bp->tx_tail = 0;
}

static void macb_reset_hw(struct macb *bp)
{
        /* Make sure we have the write buffer for ourselves */
        wmb();

        /*
         * Disable RX and TX (XXX: Should we halt the transmission
         * more gracefully?)
         */
        macb_writel(bp, NCR, 0);

        /* Clear the stats registers (XXX: Update stats first?) */
        macb_writel(bp, NCR, MACB_BIT(CLRSTAT));

        /* Clear all status flags */
        macb_writel(bp, TSR, ~0UL);
        macb_writel(bp, RSR, ~0UL);

        /* Disable all interrupts */
        macb_writel(bp, IDR, ~0UL);
        macb_readl(bp, ISR);
}

static void macb_init_hw(struct macb *bp)
{
        u32 config;

        macb_reset_hw(bp);
        __macb_set_hwaddr(bp);

        config = macb_readl(bp, NCFGR) & MACB_BF(CLK, -1L);
        config |= MACB_BIT(PAE);                /* PAuse Enable */
        config |= MACB_BIT(DRFCS);              /* Discard Rx FCS */
        if (bp->dev->flags & IFF_PROMISC)
                config |= MACB_BIT(CAF);        /* Copy All Frames */
        if (!(bp->dev->flags & IFF_BROADCAST))
                config |= MACB_BIT(NBC);        /* No BroadCast */
        macb_writel(bp, NCFGR, config);

        /* Initialize TX and RX buffers */
        macb_writel(bp, RBQP, bp->rx_ring_dma);
        macb_writel(bp, TBQP, bp->tx_ring_dma);

        /* Enable TX and RX */
        macb_writel(bp, NCR, MACB_BIT(RE) | MACB_BIT(TE) | MACB_BIT(MPE));

        /* Enable interrupts */
        macb_writel(bp, 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)));

}

/*
 * The hash address register is 64 bits long and takes up two
 * locations in the memory map.  The least significant bits are stored
 * in EMAC_HSL and the most significant bits in EMAC_HSH.
 *
 * The unicast hash enable and the multicast hash enable bits in the
 * network configuration register enable the reception of hash matched
 * frames. The destination address is reduced to a 6 bit index into
 * the 64 bit hash register using the following hash function.  The
 * hash function is an exclusive or of every sixth bit of the
 * destination address.
 *
 * hi[5] = da[5] ^ da[11] ^ da[17] ^ da[23] ^ da[29] ^ da[35] ^ da[41] ^ da[47]
 * hi[4] = da[4] ^ da[10] ^ da[16] ^ da[22] ^ da[28] ^ da[34] ^ da[40] ^ da[46]
 * hi[3] = da[3] ^ da[09] ^ da[15] ^ da[21] ^ da[27] ^ da[33] ^ da[39] ^ da[45]
 * hi[2] = da[2] ^ da[08] ^ da[14] ^ da[20] ^ da[26] ^ da[32] ^ da[38] ^ da[44]
 * hi[1] = da[1] ^ da[07] ^ da[13] ^ da[19] ^ da[25] ^ da[31] ^ da[37] ^ da[43]
 * hi[0] = da[0] ^ da[06] ^ da[12] ^ da[18] ^ da[24] ^ da[30] ^ da[36] ^ da[42]
 *
 * da[0] represents the least significant bit of the first byte
 * received, that is, the multicast/unicast indicator, and da[47]
 * represents the most significant bit of the last byte received.  If
 * the hash index, hi[n], points to a bit that is set in the hash
 * register then the frame will be matched according to whether the
 * frame is multicast or unicast.  A multicast match will be signalled
 * if the multicast hash enable bit is set, da[0] is 1 and the hash
 * index points to a bit set in the hash register.  A unicast match
 * will be signalled if the unicast hash enable bit is set, da[0] is 0
 * and the hash index points to a bit set in the hash register.  To
 * receive all multicast frames, the hash register should be set with
 * all ones and the multicast hash enable bit should be set in the
 * network configuration register.
 */

static inline int hash_bit_value(int bitnr, __u8 *addr)
{
        if (addr[bitnr / 8] & (1 << (bitnr % 8)))
                return 1;
        return 0;
}

/*
 * Return the hash index value for the specified address.
 */
static int hash_get_index(__u8 *addr)
{
        int i, j, bitval;
        int hash_index = 0;

        for (j = 0; j < 6; j++) {
                for (i = 0, bitval = 0; i < 8; i++)
                        bitval ^= hash_bit_value(i*6 + j, addr);

                hash_index |= (bitval << j);
        }

        return hash_index;
}

/*
 * Add multicast addresses to the internal multicast-hash table.
 */
static void macb_sethashtable(struct net_device *dev)
{
        struct dev_mc_list *curr;
        unsigned long mc_filter[2];
        unsigned int i, bitnr;
        struct macb *bp = netdev_priv(dev);

        mc_filter[0] = mc_filter[1] = 0;

        curr = dev->mc_list;
        for (i = 0; i < dev->mc_count; i++, curr = curr->next) {
                if (!curr) break;       /* unexpected end of list */

                bitnr = hash_get_index(curr->dmi_addr);
                mc_filter[bitnr >> 5] |= 1 << (bitnr & 31);
        }

        macb_writel(bp, HRB, mc_filter[0]);
        macb_writel(bp, HRT, mc_filter[1]);
}

/*
 * Enable/Disable promiscuous and multicast modes.
 */
static void macb_set_rx_mode(struct net_device *dev)
{
        unsigned long cfg;
        struct macb *bp = netdev_priv(dev);

        cfg = macb_readl(bp, NCFGR);

        if (dev->flags & IFF_PROMISC)
                /* Enable promiscuous mode */
                cfg |= MACB_BIT(CAF);
        else if (dev->flags & (~IFF_PROMISC))
                 /* Disable promiscuous mode */
                cfg &= ~MACB_BIT(CAF);

        if (dev->flags & IFF_ALLMULTI) {
                /* Enable all multicast mode */
                macb_writel(bp, HRB, -1);
                macb_writel(bp, HRT, -1);
                cfg |= MACB_BIT(NCFGR_MTI);
        } else if (dev->mc_count > 0) {
                /* Enable specific multicasts */
                macb_sethashtable(dev);
                cfg |= MACB_BIT(NCFGR_MTI);
        } else if (dev->flags & (~IFF_ALLMULTI)) {
                /* Disable all multicast mode */
                macb_writel(bp, HRB, 0);
                macb_writel(bp, HRT, 0);
                cfg &= ~MACB_BIT(NCFGR_MTI);
        }

        macb_writel(bp, NCFGR, cfg);
}

static int macb_open(struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        int err;

        dev_dbg(&bp->pdev->dev, "open\n");

        /* if the phy is not yet register, retry later*/
        if (!bp->phy_dev)
                return -EAGAIN;

        if (!is_valid_ether_addr(dev->dev_addr))
                return -EADDRNOTAVAIL;

        err = macb_alloc_consistent(bp);
        if (err) {
                printk(KERN_ERR
                       "%s: Unable to allocate DMA memory (error %d)\n",
                       dev->name, err);
                return err;
        }

        napi_enable(&bp->napi);

        macb_init_rings(bp);
        macb_init_hw(bp);

        /* schedule a link state check */
        phy_start(bp->phy_dev);

        netif_start_queue(dev);

        return 0;
}

static int macb_close(struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        unsigned long flags;

        netif_stop_queue(dev);
        napi_disable(&bp->napi);

        if (bp->phy_dev)
                phy_stop(bp->phy_dev);

        spin_lock_irqsave(&bp->lock, flags);
        macb_reset_hw(bp);
        netif_carrier_off(dev);
        spin_unlock_irqrestore(&bp->lock, flags);

        macb_free_consistent(bp);

        return 0;
}

static struct net_device_stats *macb_get_stats(struct net_device *dev)
{
        struct macb *bp = netdev_priv(dev);
        struct net_device_stats *nstat = &bp->stats;
        struct macb_stats *hwstat = &bp->hw_stats;

        /* read stats from hardware */
        macb_update_stats(bp);

        /* Convert HW stats into netdevice stats */
        nstat->rx_errors = (hwstat->rx_fcs_errors +
                            hwstat->rx_align_errors +
                            hwstat->rx_resource_errors +
                            hwstat->rx_overruns +
                            hwstat->rx_oversize_pkts +
                            hwstat->rx_jabbers +
                            hwstat->rx_undersize_pkts +
                            hwstat->sqe_test_errors +
                            hwstat->rx_length_mismatch);
        nstat->tx_errors = (hwstat->tx_late_cols +
                            hwstat->tx_excessive_cols +
                            hwstat->tx_underruns +
                            hwstat->tx_carrier_errors);
        nstat->collisions = (hwstat->tx_single_cols +
                             hwstat->tx_multiple_cols +
                             hwstat->tx_excessive_cols);
        nstat->rx_length_errors = (hwstat->rx_oversize_pkts +
                                   hwstat->rx_jabbers +
                                   hwstat->rx_undersize_pkts +
                                   hwstat->rx_length_mismatch);
        nstat->rx_over_errors = hwstat->rx_resource_errors;
        nstat->rx_crc_errors = hwstat->rx_fcs_errors;
        nstat->rx_frame_errors = hwstat->rx_align_errors;
        nstat->rx_fifo_errors = hwstat->rx_overruns;
        /* XXX: What does "missed" mean? */
        nstat->tx_aborted_errors = hwstat->tx_excessive_cols;
        nstat->tx_carrier_errors = hwstat->tx_carrier_errors;
        nstat->tx_fifo_errors = hwstat->tx_underruns;
        /* Don't know about heartbeat or window errors... */

        return nstat;
}

static int macb_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        struct macb *bp = netdev_priv(dev);
        struct phy_device *phydev = bp->phy_dev;

        if (!phydev)
                return -ENODEV;

        return phy_ethtool_gset(phydev, cmd);
}

static int macb_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        struct macb *bp = netdev_priv(dev);
        struct phy_device *phydev = bp->phy_dev;

        if (!phydev)
                return -ENODEV;

        return phy_ethtool_sset(phydev, cmd);
}

static void macb_get_drvinfo(struct net_device *dev,
                             struct ethtool_drvinfo *info)
{
        struct macb *bp = netdev_priv(dev);

        strcpy(info->driver, bp->pdev->dev.driver->name);
        strcpy(info->version, "$Revision: 1.14 $");
        strcpy(info->bus_info, dev_name(&bp->pdev->dev));
}

static const struct ethtool_ops macb_ethtool_ops = {
        .get_settings           = macb_get_settings,
        .set_settings           = macb_set_settings,
        .get_drvinfo            = macb_get_drvinfo,
        .get_link               = ethtool_op_get_link,
};

static int macb_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
        struct macb *bp = netdev_priv(dev);
        struct phy_device *phydev = bp->phy_dev;

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

        if (!phydev)
                return -ENODEV;

        return phy_mii_ioctl(phydev, if_mii(rq), cmd);
}

static const struct net_device_ops macb_netdev_ops = {
        .ndo_open               = macb_open,
        .ndo_stop               = macb_close,
        .ndo_start_xmit         = macb_start_xmit,
        .ndo_set_multicast_list = macb_set_rx_mode,
        .ndo_get_stats          = macb_get_stats,
        .ndo_do_ioctl           = macb_ioctl,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_change_mtu         = eth_change_mtu,
        .ndo_set_mac_address    = eth_mac_addr,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller    = macb_poll_controller,
#endif
};

static int __init macb_probe(struct platform_device *pdev)
{
        struct eth_platform_data *pdata;
        struct resource *regs;
        struct net_device *dev;
        struct macb *bp;
        struct phy_device *phydev;
        unsigned long pclk_hz;
        u32 config;
        int err = -ENXIO;

        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!regs) {
                dev_err(&pdev->dev, "no mmio resource defined\n");
                goto err_out;
        }

        err = -ENOMEM;
        dev = alloc_etherdev(sizeof(*bp));
        if (!dev) {
                dev_err(&pdev->dev, "etherdev alloc failed, aborting.\n");
                goto err_out;
        }

        SET_NETDEV_DEV(dev, &pdev->dev);

        /* TODO: Actually, we have some interesting features... */
        dev->features |= 0;

        bp = netdev_priv(dev);
        bp->pdev = pdev;
        bp->dev = dev;

        spin_lock_init(&bp->lock);

#if defined(CONFIG_ARCH_AT91)
        bp->pclk = clk_get(&pdev->dev, "macb_clk");
        if (IS_ERR(bp->pclk)) {
                dev_err(&pdev->dev, "failed to get macb_clk\n");
                goto err_out_free_dev;
        }
        clk_enable(bp->pclk);
#else
        bp->pclk = clk_get(&pdev->dev, "pclk");
        if (IS_ERR(bp->pclk)) {
                dev_err(&pdev->dev, "failed to get pclk\n");
                goto err_out_free_dev;
        }
        bp->hclk = clk_get(&pdev->dev, "hclk");
        if (IS_ERR(bp->hclk)) {
                dev_err(&pdev->dev, "failed to get hclk\n");
                goto err_out_put_pclk;
        }

        clk_enable(bp->pclk);
        clk_enable(bp->hclk);
#endif

        bp->regs = ioremap(regs->start, regs->end - regs->start + 1);
        if (!bp->regs) {
                dev_err(&pdev->dev, "failed to map registers, aborting.\n");
                err = -ENOMEM;
                goto err_out_disable_clocks;
        }

        dev->irq = platform_get_irq(pdev, 0);
        err = request_irq(dev->irq, macb_interrupt, IRQF_SAMPLE_RANDOM,
                          dev->name, dev);
        if (err) {
                printk(KERN_ERR
                       "%s: Unable to request IRQ %d (error %d)\n",
                       dev->name, dev->irq, err);
                goto err_out_iounmap;
        }

        dev->netdev_ops = &macb_netdev_ops;
        netif_napi_add(dev, &bp->napi, macb_poll, 64);
        dev->ethtool_ops = &macb_ethtool_ops;

        dev->base_addr = regs->start;

        /* Set MII management clock divider */
        pclk_hz = clk_get_rate(bp->pclk);
        if (pclk_hz <= 20000000)
                config = MACB_BF(CLK, MACB_CLK_DIV8);
        else if (pclk_hz <= 40000000)
                config = MACB_BF(CLK, MACB_CLK_DIV16);
        else if (pclk_hz <= 80000000)
                config = MACB_BF(CLK, MACB_CLK_DIV32);
        else
                config = MACB_BF(CLK, MACB_CLK_DIV64);
        macb_writel(bp, NCFGR, config);

        macb_get_hwaddr(bp);
        pdata = pdev->dev.platform_data;

        if (pdata && pdata->is_rmii)
#if defined(CONFIG_ARCH_AT91)
                macb_writel(bp, USRIO, (MACB_BIT(RMII) | MACB_BIT(CLKEN)) );
#else
                macb_writel(bp, USRIO, 0);
#endif
        else
#if defined(CONFIG_ARCH_AT91)
                macb_writel(bp, USRIO, MACB_BIT(CLKEN));
#else
                macb_writel(bp, USRIO, MACB_BIT(MII));
#endif

        bp->tx_pending = DEF_TX_RING_PENDING;

        err = register_netdev(dev);
        if (err) {
                dev_err(&pdev->dev, "Cannot register net device, aborting.\n");
                goto err_out_free_irq;
        }

        if (macb_mii_init(bp) != 0) {
                goto err_out_unregister_netdev;
        }

        platform_set_drvdata(pdev, dev);

        printk(KERN_INFO "%s: Atmel MACB at 0x%08lx irq %d (%pM)\n",
               dev->name, dev->base_addr, dev->irq, dev->dev_addr);

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

        return 0;

err_out_unregister_netdev:
        unregister_netdev(dev);
err_out_free_irq:
        free_irq(dev->irq, dev);
err_out_iounmap:
        iounmap(bp->regs);
err_out_disable_clocks:
#ifndef CONFIG_ARCH_AT91
        clk_disable(bp->hclk);
        clk_put(bp->hclk);
#endif
        clk_disable(bp->pclk);
#ifndef CONFIG_ARCH_AT91
err_out_put_pclk:
#endif
        clk_put(bp->pclk);
err_out_free_dev:
        free_netdev(dev);
err_out:
        platform_set_drvdata(pdev, NULL);
        return err;
}

static int __exit macb_remove(struct platform_device *pdev)
{
        struct net_device *dev;
        struct macb *bp;

        dev = platform_get_drvdata(pdev);

        if (dev) {
                bp = netdev_priv(dev);
                if (bp->phy_dev)
                        phy_disconnect(bp->phy_dev);
                mdiobus_unregister(bp->mii_bus);
                kfree(bp->mii_bus->irq);
                mdiobus_free(bp->mii_bus);
                unregister_netdev(dev);
                free_irq(dev->irq, dev);
                iounmap(bp->regs);
#ifndef CONFIG_ARCH_AT91
                clk_disable(bp->hclk);
                clk_put(bp->hclk);
#endif
                clk_disable(bp->pclk);
                clk_put(bp->pclk);
                free_netdev(dev);
                platform_set_drvdata(pdev, NULL);
        }

        return 0;
}

#ifdef CONFIG_PM
static int macb_suspend(struct platform_device *pdev, pm_message_t state)
{
        struct net_device *netdev = platform_get_drvdata(pdev);
        struct macb *bp = netdev_priv(netdev);

        netif_device_detach(netdev);

#ifndef CONFIG_ARCH_AT91
        clk_disable(bp->hclk);
#endif
        clk_disable(bp->pclk);

        return 0;
}

static int macb_resume(struct platform_device *pdev)
{
        struct net_device *netdev = platform_get_drvdata(pdev);
        struct macb *bp = netdev_priv(netdev);

        clk_enable(bp->pclk);
#ifndef CONFIG_ARCH_AT91
        clk_enable(bp->hclk);
#endif

        netif_device_attach(netdev);

        return 0;
}
#else
#define macb_suspend    NULL
#define macb_resume     NULL
#endif

static struct platform_driver macb_driver = {
        .remove         = __exit_p(macb_remove),
        .suspend        = macb_suspend,
        .resume         = macb_resume,
        .driver         = {
                .name           = "macb",
                .owner  = THIS_MODULE,
        },
};

static int __init macb_init(void)
{
        return platform_driver_probe(&macb_driver, macb_probe);
}

static void __exit macb_exit(void)
{
        platform_driver_unregister(&macb_driver);
}

module_init(macb_init);
module_exit(macb_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Atmel MACB Ethernet driver");
MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
MODULE_ALIAS("platform:macb");