// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2002
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 */

#include <common.h>
#include <malloc.h>
#include <net.h>
#include <netdev.h>
#include <asm/io.h>
#include <pci.h>
#include <miiphy.h>

#undef DEBUG

        /* Ethernet chip registers.
         */
#define SCBStatus               0       /* Rx/Command Unit Status *Word* */
#define SCBIntAckByte           1       /* Rx/Command Unit STAT/ACK byte */
#define SCBCmd                  2       /* Rx/Command Unit Command *Word* */
#define SCBIntrCtlByte          3       /* Rx/Command Unit Intr.Control Byte */
#define SCBPointer              4       /* General purpose pointer. */
#define SCBPort                 8       /* Misc. commands and operands. */
#define SCBflash                12      /* Flash memory control. */
#define SCBeeprom               14      /* EEPROM memory control. */
#define SCBCtrlMDI              16      /* MDI interface control. */
#define SCBEarlyRx              20      /* Early receive byte count. */
#define SCBGenControl           28      /* 82559 General Control Register */
#define SCBGenStatus            29      /* 82559 General Status register */

        /* 82559 SCB status word defnitions
         */
#define SCB_STATUS_CX           0x8000  /* CU finished command (transmit) */
#define SCB_STATUS_FR           0x4000  /* frame received */
#define SCB_STATUS_CNA          0x2000  /* CU left active state */
#define SCB_STATUS_RNR          0x1000  /* receiver left ready state */
#define SCB_STATUS_MDI          0x0800  /* MDI read/write cycle done */
#define SCB_STATUS_SWI          0x0400  /* software generated interrupt */
#define SCB_STATUS_FCP          0x0100  /* flow control pause interrupt */

#define SCB_INTACK_MASK         0xFD00  /* all the above */

#define SCB_INTACK_TX           (SCB_STATUS_CX | SCB_STATUS_CNA)
#define SCB_INTACK_RX           (SCB_STATUS_FR | SCB_STATUS_RNR)

        /* System control block commands
         */
/* CU Commands */
#define CU_NOP                  0x0000
#define CU_START                0x0010
#define CU_RESUME               0x0020
#define CU_STATSADDR            0x0040  /* Load Dump Statistics ctrs addr */
#define CU_SHOWSTATS            0x0050  /* Dump statistics counters. */
#define CU_ADDR_LOAD            0x0060  /* Base address to add to CU commands */
#define CU_DUMPSTATS            0x0070  /* Dump then reset stats counters. */

/* RUC Commands */
#define RUC_NOP                 0x0000
#define RUC_START               0x0001
#define RUC_RESUME              0x0002
#define RUC_ABORT               0x0004
#define RUC_ADDR_LOAD           0x0006  /* (seems not to clear on acceptance) */
#define RUC_RESUMENR            0x0007

#define CU_CMD_MASK             0x00f0
#define RU_CMD_MASK             0x0007

#define SCB_M                   0x0100  /* 0 = enable interrupt, 1 = disable */
#define SCB_SWI                 0x0200  /* 1 - cause device to interrupt */

#define CU_STATUS_MASK          0x00C0
#define RU_STATUS_MASK          0x003C

#define RU_STATUS_IDLE          (0<<2)
#define RU_STATUS_SUS           (1<<2)
#define RU_STATUS_NORES         (2<<2)
#define RU_STATUS_READY         (4<<2)
#define RU_STATUS_NO_RBDS_SUS   ((1<<2)|(8<<2))
#define RU_STATUS_NO_RBDS_NORES ((2<<2)|(8<<2))
#define RU_STATUS_NO_RBDS_READY ((4<<2)|(8<<2))

        /* 82559 Port interface commands.
         */
#define I82559_RESET            0x00000000      /* Software reset */
#define I82559_SELFTEST         0x00000001      /* 82559 Selftest command */
#define I82559_SELECTIVE_RESET  0x00000002
#define I82559_DUMP             0x00000003
#define I82559_DUMP_WAKEUP      0x00000007

        /* 82559 Eeprom interface.
         */
#define EE_SHIFT_CLK            0x01    /* EEPROM shift clock. */
#define EE_CS                   0x02    /* EEPROM chip select. */
#define EE_DATA_WRITE           0x04    /* EEPROM chip data in. */
#define EE_WRITE_0              0x01
#define EE_WRITE_1              0x05
#define EE_DATA_READ            0x08    /* EEPROM chip data out. */
#define EE_ENB                  (0x4800 | EE_CS)
#define EE_CMD_BITS             3
#define EE_DATA_BITS            16

        /* The EEPROM commands include the alway-set leading bit.
         */
#define EE_EWENB_CMD            (4 << addr_len)
#define EE_WRITE_CMD            (5 << addr_len)
#define EE_READ_CMD             (6 << addr_len)
#define EE_ERASE_CMD            (7 << addr_len)

        /* Receive frame descriptors.
         */
struct RxFD {
        volatile u16 status;
        volatile u16 control;
        volatile u32 link;              /* struct RxFD * */
        volatile u32 rx_buf_addr;       /* void * */
        volatile u32 count;

        volatile u8 data[PKTSIZE_ALIGN];
};

#define RFD_STATUS_C            0x8000  /* completion of received frame */
#define RFD_STATUS_OK           0x2000  /* frame received with no errors */

#define RFD_CONTROL_EL          0x8000  /* 1=last RFD in RFA */
#define RFD_CONTROL_S           0x4000  /* 1=suspend RU after receiving frame */
#define RFD_CONTROL_H           0x0010  /* 1=RFD is a header RFD */
#define RFD_CONTROL_SF          0x0008  /* 0=simplified, 1=flexible mode */

#define RFD_COUNT_MASK          0x3fff
#define RFD_COUNT_F             0x4000
#define RFD_COUNT_EOF           0x8000

#define RFD_RX_CRC              0x0800  /* crc error */
#define RFD_RX_ALIGNMENT        0x0400  /* alignment error */
#define RFD_RX_RESOURCE         0x0200  /* out of space, no resources */
#define RFD_RX_DMA_OVER         0x0100  /* DMA overrun */
#define RFD_RX_SHORT            0x0080  /* short frame error */
#define RFD_RX_LENGTH           0x0020
#define RFD_RX_ERROR            0x0010  /* receive error */
#define RFD_RX_NO_ADR_MATCH     0x0004  /* no address match */
#define RFD_RX_IA_MATCH         0x0002  /* individual address does not match */
#define RFD_RX_TCO              0x0001  /* TCO indication */

        /* Transmit frame descriptors
         */
struct TxFD {                           /* Transmit frame descriptor set. */
        volatile u16 status;
        volatile u16 command;
        volatile u32 link;              /* void * */
        volatile u32 tx_desc_addr;      /* Always points to the tx_buf_addr element. */
        volatile s32 count;

        volatile u32 tx_buf_addr0;      /* void *, frame to be transmitted.  */
        volatile s32 tx_buf_size0;      /* Length of Tx frame. */
        volatile u32 tx_buf_addr1;      /* void *, frame to be transmitted.  */
        volatile s32 tx_buf_size1;      /* Length of Tx frame. */
};

#define TxCB_CMD_TRANSMIT       0x0004  /* transmit command */
#define TxCB_CMD_SF             0x0008  /* 0=simplified, 1=flexible mode */
#define TxCB_CMD_NC             0x0010  /* 0=CRC insert by controller */
#define TxCB_CMD_I              0x2000  /* generate interrupt on completion */
#define TxCB_CMD_S              0x4000  /* suspend on completion */
#define TxCB_CMD_EL             0x8000  /* last command block in CBL */

#define TxCB_COUNT_MASK         0x3fff
#define TxCB_COUNT_EOF          0x8000

        /* The Speedo3 Rx and Tx frame/buffer descriptors.
         */
struct descriptor {                     /* A generic descriptor. */
        volatile u16 status;
        volatile u16 command;
        volatile u32 link;              /* struct descriptor *  */

        unsigned char params[0];
};

#define CONFIG_SYS_CMD_EL               0x8000
#define CONFIG_SYS_CMD_SUSPEND          0x4000
#define CONFIG_SYS_CMD_INT              0x2000
#define CONFIG_SYS_CMD_IAS              0x0001  /* individual address setup */
#define CONFIG_SYS_CMD_CONFIGURE        0x0002  /* configure */

#define CONFIG_SYS_STATUS_C             0x8000
#define CONFIG_SYS_STATUS_OK            0x2000

        /* Misc.
         */
#define NUM_RX_DESC             PKTBUFSRX
#define NUM_TX_DESC             1       /* Number of TX descriptors   */

#define TOUT_LOOP               1000000

#define ETH_ALEN                6

static struct RxFD rx_ring[NUM_RX_DESC];        /* RX descriptor ring         */
static struct TxFD tx_ring[NUM_TX_DESC];        /* TX descriptor ring         */
static int rx_next;                     /* RX descriptor ring pointer */
static int tx_next;                     /* TX descriptor ring pointer */
static int tx_threshold;

/*
 * The parameters for a CmdConfigure operation.
 * There are so many options that it would be difficult to document
 * each bit. We mostly use the default or recommended settings.
 */
static const char i82558_config_cmd[] = {
        22, 0x08, 0, 1, 0, 0, 0x22, 0x03, 1,    /* 1=Use MII  0=Use AUI */
        0, 0x2E, 0, 0x60, 0x08, 0x88,
        0x68, 0, 0x40, 0xf2, 0x84,              /* Disable FC */
        0x31, 0x05,
};

static void init_rx_ring (struct eth_device *dev);
static void purge_tx_ring (struct eth_device *dev);

static void read_hw_addr (struct eth_device *dev, bd_t * bis);

static int eepro100_init (struct eth_device *dev, bd_t * bis);
static int eepro100_send(struct eth_device *dev, void *packet, int length);
static int eepro100_recv (struct eth_device *dev);
static void eepro100_halt (struct eth_device *dev);

#if defined(CONFIG_E500)
#define bus_to_phys(a) (a)
#define phys_to_bus(a) (a)
#else
#define bus_to_phys(a)  pci_mem_to_phys((pci_dev_t)dev->priv, a)
#define phys_to_bus(a)  pci_phys_to_mem((pci_dev_t)dev->priv, a)
#endif

static inline int INW (struct eth_device *dev, u_long addr)
{
        return le16_to_cpu(*(volatile u16 *)(addr + (u_long)dev->iobase));
}

static inline void OUTW (struct eth_device *dev, int command, u_long addr)
{
        *(volatile u16 *)((addr + (u_long)dev->iobase)) = cpu_to_le16(command);
}

static inline void OUTL (struct eth_device *dev, int command, u_long addr)
{
        *(volatile u32 *)((addr + (u_long)dev->iobase)) = cpu_to_le32(command);
}

#if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)
static inline int INL (struct eth_device *dev, u_long addr)
{
        return le32_to_cpu(*(volatile u32 *)(addr + (u_long)dev->iobase));
}

static int get_phyreg (struct eth_device *dev, unsigned char addr,
                unsigned char reg, unsigned short *value)
{
        int cmd;
        int timeout = 50;

        /* read requested data */
        cmd = (2 << 26) | ((addr & 0x1f) << 21) | ((reg & 0x1f) << 16);
        OUTL (dev, cmd, SCBCtrlMDI);

        do {
                udelay(1000);
                cmd = INL (dev, SCBCtrlMDI);
        } while (!(cmd & (1 << 28)) && (--timeout));

        if (timeout == 0)
                return -1;

        *value = (unsigned short) (cmd & 0xffff);

        return 0;
}

static int set_phyreg (struct eth_device *dev, unsigned char addr,
                unsigned char reg, unsigned short value)
{
        int cmd;
        int timeout = 50;

        /* write requested data */
        cmd = (1 << 26) | ((addr & 0x1f) << 21) | ((reg & 0x1f) << 16);
        OUTL (dev, cmd | value, SCBCtrlMDI);

        while (!(INL (dev, SCBCtrlMDI) & (1 << 28)) && (--timeout))
                udelay(1000);

        if (timeout == 0)
                return -1;

        return 0;
}

/* Check if given phyaddr is valid, i.e. there is a PHY connected.
 * Do this by checking model value field from ID2 register.
 */
static struct eth_device* verify_phyaddr (const char *devname,
                                                unsigned char addr)
{
        struct eth_device *dev;
        unsigned short value;
        unsigned char model;

        dev = eth_get_dev_by_name(devname);
        if (dev == NULL) {
                printf("%s: no such device\n", devname);
                return NULL;
        }

        /* read id2 register */
        if (get_phyreg(dev, addr, MII_PHYSID2, &value) != 0) {
                printf("%s: mii read timeout!\n", devname);
                return NULL;
        }

        /* get model */
        model = (unsigned char)((value >> 4) & 0x003f);

        if (model == 0) {
                printf("%s: no PHY at address %d\n", devname, addr);
                return NULL;
        }

        return dev;
}

static int eepro100_miiphy_read(struct mii_dev *bus, int addr, int devad,
                                int reg)
{
        unsigned short value = 0;
        struct eth_device *dev;

        dev = verify_phyaddr(bus->name, addr);
        if (dev == NULL)
                return -1;

        if (get_phyreg(dev, addr, reg, &value) != 0) {
                printf("%s: mii read timeout!\n", bus->name);
                return -1;
        }

        return value;
}

static int eepro100_miiphy_write(struct mii_dev *bus, int addr, int devad,
                                 int reg, u16 value)
{
        struct eth_device *dev;

        dev = verify_phyaddr(bus->name, addr);
        if (dev == NULL)
                return -1;

        if (set_phyreg(dev, addr, reg, value) != 0) {
                printf("%s: mii write timeout!\n", bus->name);
                return -1;
        }

        return 0;
}

#endif

/* Wait for the chip get the command.
*/
static int wait_for_eepro100 (struct eth_device *dev)
{
        int i;

        for (i = 0; INW (dev, SCBCmd) & (CU_CMD_MASK | RU_CMD_MASK); i++) {
                if (i >= TOUT_LOOP) {
                        return 0;
                }
        }

        return 1;
}

static struct pci_device_id supported[] = {
        {PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82557},
        {PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82559},
        {PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82559ER},
        {}
};

int eepro100_initialize (bd_t * bis)
{
        pci_dev_t devno;
        int card_number = 0;
        struct eth_device *dev;
        u32 iobase, status;
        int idx = 0;

        while (1) {
                /* Find PCI device
                 */
                if ((devno = pci_find_devices (supported, idx++)) < 0) {
                        break;
                }

                pci_read_config_dword (devno, PCI_BASE_ADDRESS_0, &iobase);
                iobase &= ~0xf;

#ifdef DEBUG
                printf ("eepro100: Intel i82559 PCI EtherExpressPro @0x%x\n",
                                iobase);
#endif

                pci_write_config_dword (devno,
                                        PCI_COMMAND,
                                        PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);

                /* Check if I/O accesses and Bus Mastering are enabled.
                 */
                pci_read_config_dword (devno, PCI_COMMAND, &status);
                if (!(status & PCI_COMMAND_MEMORY)) {
                        printf ("Error: Can not enable MEM access.\n");
                        continue;
                }

                if (!(status & PCI_COMMAND_MASTER)) {
                        printf ("Error: Can not enable Bus Mastering.\n");
                        continue;
                }

                dev = (struct eth_device *) malloc (sizeof *dev);
                if (!dev) {
                        printf("eepro100: Can not allocate memory\n");
                        break;
                }
                memset(dev, 0, sizeof(*dev));

                sprintf (dev->name, "i82559#%d", card_number);
                dev->priv = (void *) devno; /* this have to come before bus_to_phys() */
                dev->iobase = bus_to_phys (iobase);
                dev->init = eepro100_init;
                dev->halt = eepro100_halt;
                dev->send = eepro100_send;
                dev->recv = eepro100_recv;

                eth_register (dev);

#if defined (CONFIG_MII) || defined(CONFIG_CMD_MII)
                /* register mii command access routines */
                int retval;
                struct mii_dev *mdiodev = mdio_alloc();
                if (!mdiodev)
                        return -ENOMEM;
                strncpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
                mdiodev->read = eepro100_miiphy_read;
                mdiodev->write = eepro100_miiphy_write;

                retval = mdio_register(mdiodev);
                if (retval < 0)
                        return retval;
#endif

                card_number++;

                /* Set the latency timer for value.
                 */
                pci_write_config_byte (devno, PCI_LATENCY_TIMER, 0x20);

                udelay (10 * 1000);

                read_hw_addr (dev, bis);
        }

        return card_number;
}


static int eepro100_init (struct eth_device *dev, bd_t * bis)
{
        int i, status = -1;
        int tx_cur;
        struct descriptor *ias_cmd, *cfg_cmd;

        /* Reset the ethernet controller
         */
        OUTL (dev, I82559_SELECTIVE_RESET, SCBPort);
        udelay (20);

        OUTL (dev, I82559_RESET, SCBPort);
        udelay (20);

        if (!wait_for_eepro100 (dev)) {
                printf ("Error: Can not reset ethernet controller.\n");
                goto Done;
        }
        OUTL (dev, 0, SCBPointer);
        OUTW (dev, SCB_M | RUC_ADDR_LOAD, SCBCmd);

        if (!wait_for_eepro100 (dev)) {
                printf ("Error: Can not reset ethernet controller.\n");
                goto Done;
        }
        OUTL (dev, 0, SCBPointer);
        OUTW (dev, SCB_M | CU_ADDR_LOAD, SCBCmd);

        /* Initialize Rx and Tx rings.
         */
        init_rx_ring (dev);
        purge_tx_ring (dev);

        /* Tell the adapter where the RX ring is located.
         */
        if (!wait_for_eepro100 (dev)) {
                printf ("Error: Can not reset ethernet controller.\n");
                goto Done;
        }

        OUTL (dev, phys_to_bus ((u32) & rx_ring[rx_next]), SCBPointer);
        OUTW (dev, SCB_M | RUC_START, SCBCmd);

        /* Send the Configure frame */
        tx_cur = tx_next;
        tx_next = ((tx_next + 1) % NUM_TX_DESC);

        cfg_cmd = (struct descriptor *) &tx_ring[tx_cur];
        cfg_cmd->command = cpu_to_le16 ((CONFIG_SYS_CMD_SUSPEND | CONFIG_SYS_CMD_CONFIGURE));
        cfg_cmd->status = 0;
        cfg_cmd->link = cpu_to_le32 (phys_to_bus ((u32) & tx_ring[tx_next]));

        memcpy (cfg_cmd->params, i82558_config_cmd,
                        sizeof (i82558_config_cmd));

        if (!wait_for_eepro100 (dev)) {
                printf ("Error---CONFIG_SYS_CMD_CONFIGURE: Can not reset ethernet controller.\n");
                goto Done;
        }

        OUTL (dev, phys_to_bus ((u32) & tx_ring[tx_cur]), SCBPointer);
        OUTW (dev, SCB_M | CU_START, SCBCmd);

        for (i = 0;
             !(le16_to_cpu (tx_ring[tx_cur].status) & CONFIG_SYS_STATUS_C);
             i++) {
                if (i >= TOUT_LOOP) {
                        printf ("%s: Tx error buffer not ready\n", dev->name);
                        goto Done;
                }
        }

        if (!(le16_to_cpu (tx_ring[tx_cur].status) & CONFIG_SYS_STATUS_OK)) {
                printf ("TX error status = 0x%08X\n",
                        le16_to_cpu (tx_ring[tx_cur].status));
                goto Done;
        }

        /* Send the Individual Address Setup frame
         */
        tx_cur = tx_next;
        tx_next = ((tx_next + 1) % NUM_TX_DESC);

        ias_cmd = (struct descriptor *) &tx_ring[tx_cur];
        ias_cmd->command = cpu_to_le16 ((CONFIG_SYS_CMD_SUSPEND | CONFIG_SYS_CMD_IAS));
        ias_cmd->status = 0;
        ias_cmd->link = cpu_to_le32 (phys_to_bus ((u32) & tx_ring[tx_next]));

        memcpy (ias_cmd->params, dev->enetaddr, 6);

        /* Tell the adapter where the TX ring is located.
         */
        if (!wait_for_eepro100 (dev)) {
                printf ("Error: Can not reset ethernet controller.\n");
                goto Done;
        }

        OUTL (dev, phys_to_bus ((u32) & tx_ring[tx_cur]), SCBPointer);
        OUTW (dev, SCB_M | CU_START, SCBCmd);

        for (i = 0; !(le16_to_cpu (tx_ring[tx_cur].status) & CONFIG_SYS_STATUS_C);
                 i++) {
                if (i >= TOUT_LOOP) {
                        printf ("%s: Tx error buffer not ready\n",
                                dev->name);
                        goto Done;
                }
        }

        if (!(le16_to_cpu (tx_ring[tx_cur].status) & CONFIG_SYS_STATUS_OK)) {
                printf ("TX error status = 0x%08X\n",
                        le16_to_cpu (tx_ring[tx_cur].status));
                goto Done;
        }

        status = 0;

  Done:
        return status;
}

static int eepro100_send(struct eth_device *dev, void *packet, int length)
{
        int i, status = -1;
        int tx_cur;

        if (length <= 0) {
                printf ("%s: bad packet size: %d\n", dev->name, length);
                goto Done;
        }

        tx_cur = tx_next;
        tx_next = (tx_next + 1) % NUM_TX_DESC;

        tx_ring[tx_cur].command = cpu_to_le16 ( TxCB_CMD_TRANSMIT |
                                                TxCB_CMD_SF     |
                                                TxCB_CMD_S      |
                                                TxCB_CMD_EL );
        tx_ring[tx_cur].status = 0;
        tx_ring[tx_cur].count = cpu_to_le32 (tx_threshold);
        tx_ring[tx_cur].link =
                cpu_to_le32 (phys_to_bus ((u32) & tx_ring[tx_next]));
        tx_ring[tx_cur].tx_desc_addr =
                cpu_to_le32 (phys_to_bus ((u32) & tx_ring[tx_cur].tx_buf_addr0));
        tx_ring[tx_cur].tx_buf_addr0 =
                cpu_to_le32 (phys_to_bus ((u_long) packet));
        tx_ring[tx_cur].tx_buf_size0 = cpu_to_le32 (length);

        if (!wait_for_eepro100 (dev)) {
                printf ("%s: Tx error ethernet controller not ready.\n",
                                dev->name);
                goto Done;
        }

        /* Send the packet.
         */
        OUTL (dev, phys_to_bus ((u32) & tx_ring[tx_cur]), SCBPointer);
        OUTW (dev, SCB_M | CU_START, SCBCmd);

        for (i = 0; !(le16_to_cpu (tx_ring[tx_cur].status) & CONFIG_SYS_STATUS_C);
                 i++) {
                if (i >= TOUT_LOOP) {
                        printf ("%s: Tx error buffer not ready\n", dev->name);
                        goto Done;
                }
        }

        if (!(le16_to_cpu (tx_ring[tx_cur].status) & CONFIG_SYS_STATUS_OK)) {
                printf ("TX error status = 0x%08X\n",
                        le16_to_cpu (tx_ring[tx_cur].status));
                goto Done;
        }

        status = length;

  Done:
        return status;
}

static int eepro100_recv (struct eth_device *dev)
{
        u16 status, stat;
        int rx_prev, length = 0;

        stat = INW (dev, SCBStatus);
        OUTW (dev, stat & SCB_STATUS_RNR, SCBStatus);

        for (;;) {
                status = le16_to_cpu (rx_ring[rx_next].status);

                if (!(status & RFD_STATUS_C)) {
                        break;
                }

                /* Valid frame status.
                 */
                if ((status & RFD_STATUS_OK)) {
                        /* A valid frame received.
                         */
                        length = le32_to_cpu (rx_ring[rx_next].count) & 0x3fff;

                        /* Pass the packet up to the protocol
                         * layers.
                         */
                        net_process_received_packet((u8 *)rx_ring[rx_next].data,
                                                    length);
                } else {
                        /* There was an error.
                         */
                        printf ("RX error status = 0x%08X\n", status);
                }

                rx_ring[rx_next].control = cpu_to_le16 (RFD_CONTROL_S);
                rx_ring[rx_next].status = 0;
                rx_ring[rx_next].count = cpu_to_le32 (PKTSIZE_ALIGN << 16);

                rx_prev = (rx_next + NUM_RX_DESC - 1) % NUM_RX_DESC;
                rx_ring[rx_prev].control = 0;

                /* Update entry information.
                 */
                rx_next = (rx_next + 1) % NUM_RX_DESC;
        }

        if (stat & SCB_STATUS_RNR) {

                printf ("%s: Receiver is not ready, restart it !\n", dev->name);

                /* Reinitialize Rx ring.
                 */
                init_rx_ring (dev);

                if (!wait_for_eepro100 (dev)) {
                        printf ("Error: Can not restart ethernet controller.\n");
                        goto Done;
                }

                OUTL (dev, phys_to_bus ((u32) & rx_ring[rx_next]), SCBPointer);
                OUTW (dev, SCB_M | RUC_START, SCBCmd);
        }

  Done:
        return length;
}

static void eepro100_halt (struct eth_device *dev)
{
        /* Reset the ethernet controller
         */
        OUTL (dev, I82559_SELECTIVE_RESET, SCBPort);
        udelay (20);

        OUTL (dev, I82559_RESET, SCBPort);
        udelay (20);

        if (!wait_for_eepro100 (dev)) {
                printf ("Error: Can not reset ethernet controller.\n");
                goto Done;
        }
        OUTL (dev, 0, SCBPointer);
        OUTW (dev, SCB_M | RUC_ADDR_LOAD, SCBCmd);

        if (!wait_for_eepro100 (dev)) {
                printf ("Error: Can not reset ethernet controller.\n");
                goto Done;
        }
        OUTL (dev, 0, SCBPointer);
        OUTW (dev, SCB_M | CU_ADDR_LOAD, SCBCmd);

  Done:
        return;
}

        /* SROM Read.
         */
static int read_eeprom (struct eth_device *dev, int location, int addr_len)
{
        unsigned short retval = 0;
        int read_cmd = location | EE_READ_CMD;
        int i;

        OUTW (dev, EE_ENB & ~EE_CS, SCBeeprom);
        OUTW (dev, EE_ENB, SCBeeprom);

        /* Shift the read command bits out. */
        for (i = 12; i >= 0; i--) {
                short dataval = (read_cmd & (1 << i)) ? EE_DATA_WRITE : 0;

                OUTW (dev, EE_ENB | dataval, SCBeeprom);
                udelay (1);
                OUTW (dev, EE_ENB | dataval | EE_SHIFT_CLK, SCBeeprom);
                udelay (1);
        }
        OUTW (dev, EE_ENB, SCBeeprom);

        for (i = 15; i >= 0; i--) {
                OUTW (dev, EE_ENB | EE_SHIFT_CLK, SCBeeprom);
                udelay (1);
                retval = (retval << 1) |
                                ((INW (dev, SCBeeprom) & EE_DATA_READ) ? 1 : 0);
                OUTW (dev, EE_ENB, SCBeeprom);
                udelay (1);
        }

        /* Terminate the EEPROM access. */
        OUTW (dev, EE_ENB & ~EE_CS, SCBeeprom);
        return retval;
}

#ifdef CONFIG_EEPRO100_SROM_WRITE
int eepro100_write_eeprom (struct eth_device* dev, int location, int addr_len, unsigned short data)
{
    unsigned short dataval;
    int enable_cmd = 0x3f | EE_EWENB_CMD;
    int write_cmd  = location | EE_WRITE_CMD;
    int i;
    unsigned long datalong, tmplong;

    OUTW(dev, EE_ENB & ~EE_CS, SCBeeprom);
    udelay(1);
    OUTW(dev, EE_ENB, SCBeeprom);

    /* Shift the enable command bits out. */
    for (i = (addr_len+EE_CMD_BITS-1); i >= 0; i--)
    {
        dataval = (enable_cmd & (1 << i)) ? EE_DATA_WRITE : 0;
        OUTW(dev, EE_ENB | dataval, SCBeeprom);
        udelay(1);
        OUTW(dev, EE_ENB | dataval | EE_SHIFT_CLK, SCBeeprom);
        udelay(1);
    }

    OUTW(dev, EE_ENB, SCBeeprom);
    udelay(1);
    OUTW(dev, EE_ENB & ~EE_CS, SCBeeprom);
    udelay(1);
    OUTW(dev, EE_ENB, SCBeeprom);


    /* Shift the write command bits out. */
    for (i = (addr_len+EE_CMD_BITS-1); i >= 0; i--)
    {
        dataval = (write_cmd & (1 << i)) ? EE_DATA_WRITE : 0;
        OUTW(dev, EE_ENB | dataval, SCBeeprom);
        udelay(1);
        OUTW(dev, EE_ENB | dataval | EE_SHIFT_CLK, SCBeeprom);
        udelay(1);
    }

    /* Write the data */
    datalong= (unsigned long) ((((data) & 0x00ff) << 8) | ( (data) >> 8));

    for (i = 0; i< EE_DATA_BITS; i++)
    {
    /* Extract and move data bit to bit DI */
    dataval = ((datalong & 0x8000)>>13) ? EE_DATA_WRITE : 0;

    OUTW(dev, EE_ENB | dataval, SCBeeprom);
    udelay(1);
    OUTW(dev, EE_ENB | dataval | EE_SHIFT_CLK, SCBeeprom);
    udelay(1);
    OUTW(dev, EE_ENB | dataval, SCBeeprom);
    udelay(1);

    datalong = datalong << 1;   /* Adjust significant data bit*/
    }

    /* Finish up command  (toggle CS) */
    OUTW(dev, EE_ENB & ~EE_CS, SCBeeprom);
    udelay(1);                  /* delay for more than 250 ns */
    OUTW(dev, EE_ENB, SCBeeprom);

    /* Wait for programming ready (D0 = 1) */
    tmplong = 10;
    do
    {
        dataval = INW(dev, SCBeeprom);
        if (dataval & EE_DATA_READ)
            break;
        udelay(10000);
    }
    while (-- tmplong);

    if (tmplong == 0)
    {
        printf ("Write i82559 eeprom timed out (100 ms waiting for data ready.\n");
        return -1;
    }

    /* Terminate the EEPROM access. */
    OUTW(dev, EE_ENB & ~EE_CS, SCBeeprom);

    return 0;
}
#endif

static void init_rx_ring (struct eth_device *dev)
{
        int i;

        for (i = 0; i < NUM_RX_DESC; i++) {
                rx_ring[i].status = 0;
                rx_ring[i].control =
                                (i == NUM_RX_DESC - 1) ? cpu_to_le16 (RFD_CONTROL_S) : 0;
                rx_ring[i].link =
                                cpu_to_le32 (phys_to_bus
                                                         ((u32) & rx_ring[(i + 1) % NUM_RX_DESC]));
                rx_ring[i].rx_buf_addr = 0xffffffff;
                rx_ring[i].count = cpu_to_le32 (PKTSIZE_ALIGN << 16);
        }

        rx_next = 0;
}

static void purge_tx_ring (struct eth_device *dev)
{
        int i;

        tx_next = 0;
        tx_threshold = 0x01208000;

        for (i = 0; i < NUM_TX_DESC; i++) {
                tx_ring[i].status = 0;
                tx_ring[i].command = 0;
                tx_ring[i].link = 0;
                tx_ring[i].tx_desc_addr = 0;
                tx_ring[i].count = 0;

                tx_ring[i].tx_buf_addr0 = 0;
                tx_ring[i].tx_buf_size0 = 0;
                tx_ring[i].tx_buf_addr1 = 0;
                tx_ring[i].tx_buf_size1 = 0;
        }
}

static void read_hw_addr (struct eth_device *dev, bd_t * bis)
{
        u16 sum = 0;
        int i, j;
        int addr_len = read_eeprom (dev, 0, 6) == 0xffff ? 8 : 6;

        for (j = 0, i = 0; i < 0x40; i++) {
                u16 value = read_eeprom (dev, i, addr_len);

                sum += value;
                if (i < 3) {
                        dev->enetaddr[j++] = value;
                        dev->enetaddr[j++] = value >> 8;
                }
        }

        if (sum != 0xBABA) {
                memset (dev->enetaddr, 0, ETH_ALEN);
#ifdef DEBUG
                printf ("%s: Invalid EEPROM checksum %#4.4x, "
                        "check settings before activating this device!\n",
                        dev->name, sum);
#endif
        }
}