/*
 *    Lance ethernet driver for the MIPS processor based
 *      DECstation family
 *
 *
 *      adopted from sunlance.c by Richard van den Berg
 *
 *      Copyright (C) 2002, 2003, 2005, 2006  Maciej W. Rozycki
 *
 *      additional sources:
 *      - PMAD-AA TURBOchannel Ethernet Module Functional Specification,
 *        Revision 1.2
 *
 *      History:
 *
 *      v0.001: The kernel accepts the code and it shows the hardware address.
 *
 *      v0.002: Removed most sparc stuff, left only some module and dma stuff.
 *
 *      v0.003: Enhanced base address calculation from proposals by
 *              Harald Koerfgen and Thomas Riemer.
 *
 *      v0.004: lance-regs is pointing at the right addresses, added prom
 *              check. First start of address mapping and DMA.
 *
 *      v0.005: started to play around with LANCE-DMA. This driver will not
 *              work for non IOASIC lances. HK
 *
 *      v0.006: added pointer arrays to lance_private and setup routine for
 *              them in dec_lance_init. HK
 *
 *      v0.007: Big shit. The LANCE seems to use a different DMA mechanism to
 *              access the init block. This looks like one (short) word at a
 *              time, but the smallest amount the IOASIC can transfer is a
 *              (long) word. So we have a 2-2 padding here. Changed
 *              lance_init_block accordingly. The 16-16 padding for the buffers
 *              seems to be correct. HK
 *
 *      v0.008: mods to make PMAX_LANCE work. 01/09/1999 triemer
 *
 *      v0.009: Module support fixes, multiple interfaces support, various
 *              bits. macro
 *
 *      v0.010: Fixes for the PMAD mapping of the LANCE buffer and for the
 *              PMAX requirement to only use halfword accesses to the
 *              buffer. macro
 *
 *      v0.011: Converted the PMAD to the driver model. macro
 */

#include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/if_ether.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/tc.h>
#include <linux/types.h>

#include <asm/addrspace.h>
#include <asm/system.h>

#include <asm/dec/interrupts.h>
#include <asm/dec/ioasic.h>
#include <asm/dec/ioasic_addrs.h>
#include <asm/dec/kn01.h>
#include <asm/dec/machtype.h>
#include <asm/dec/system.h>

static char version[] __devinitdata =
"declance.c: v0.011 by Linux MIPS DECstation task force\n";

MODULE_AUTHOR("Linux MIPS DECstation task force");
MODULE_DESCRIPTION("DEC LANCE (DECstation onboard, PMAD-xx) driver");
MODULE_LICENSE("GPL");

#define __unused __attribute__ ((unused))

/*
 * card types
 */
#define ASIC_LANCE 1
#define PMAD_LANCE 2
#define PMAX_LANCE 3


#define LE_CSR0 0
#define LE_CSR1 1
#define LE_CSR2 2
#define LE_CSR3 3

#define LE_MO_PROM      0x8000  /* Enable promiscuous mode */

#define LE_C0_ERR       0x8000  /* Error: set if BAB, SQE, MISS or ME is set */
#define LE_C0_BABL      0x4000  /* BAB:  Babble: tx timeout. */
#define LE_C0_CERR      0x2000  /* SQE:  Signal quality error */
#define LE_C0_MISS      0x1000  /* MISS: Missed a packet */
#define LE_C0_MERR      0x0800  /* ME:   Memory error */
#define LE_C0_RINT      0x0400  /* Received interrupt */
#define LE_C0_TINT      0x0200  /* Transmitter Interrupt */
#define LE_C0_IDON      0x0100  /* IFIN: Init finished. */
#define LE_C0_INTR      0x0080  /* Interrupt or error */
#define LE_C0_INEA      0x0040  /* Interrupt enable */
#define LE_C0_RXON      0x0020  /* Receiver on */
#define LE_C0_TXON      0x0010  /* Transmitter on */
#define LE_C0_TDMD      0x0008  /* Transmitter demand */
#define LE_C0_STOP      0x0004  /* Stop the card */
#define LE_C0_STRT      0x0002  /* Start the card */
#define LE_C0_INIT      0x0001  /* Init the card */

#define LE_C3_BSWP      0x4     /* SWAP */
#define LE_C3_ACON      0x2     /* ALE Control */
#define LE_C3_BCON      0x1     /* Byte control */

/* Receive message descriptor 1 */
#define LE_R1_OWN       0x8000  /* Who owns the entry */
#define LE_R1_ERR       0x4000  /* Error: if FRA, OFL, CRC or BUF is set */
#define LE_R1_FRA       0x2000  /* FRA: Frame error */
#define LE_R1_OFL       0x1000  /* OFL: Frame overflow */
#define LE_R1_CRC       0x0800  /* CRC error */
#define LE_R1_BUF       0x0400  /* BUF: Buffer error */
#define LE_R1_SOP       0x0200  /* Start of packet */
#define LE_R1_EOP       0x0100  /* End of packet */
#define LE_R1_POK       0x0300  /* Packet is complete: SOP + EOP */

/* Transmit message descriptor 1 */
#define LE_T1_OWN       0x8000  /* Lance owns the packet */
#define LE_T1_ERR       0x4000  /* Error summary */
#define LE_T1_EMORE     0x1000  /* Error: more than one retry needed */
#define LE_T1_EONE      0x0800  /* Error: one retry needed */
#define LE_T1_EDEF      0x0400  /* Error: deferred */
#define LE_T1_SOP       0x0200  /* Start of packet */
#define LE_T1_EOP       0x0100  /* End of packet */
#define LE_T1_POK       0x0300  /* Packet is complete: SOP + EOP */

#define LE_T3_BUF       0x8000  /* Buffer error */
#define LE_T3_UFL       0x4000  /* Error underflow */
#define LE_T3_LCOL      0x1000  /* Error late collision */
#define LE_T3_CLOS      0x0800  /* Error carrier loss */
#define LE_T3_RTY       0x0400  /* Error retry */
#define LE_T3_TDR       0x03ff  /* Time Domain Reflectometry counter */

/* Define: 2^4 Tx buffers and 2^4 Rx buffers */

#ifndef LANCE_LOG_TX_BUFFERS
#define LANCE_LOG_TX_BUFFERS 4
#define LANCE_LOG_RX_BUFFERS 4
#endif

#define TX_RING_SIZE                    (1 << (LANCE_LOG_TX_BUFFERS))
#define TX_RING_MOD_MASK                (TX_RING_SIZE - 1)

#define RX_RING_SIZE                    (1 << (LANCE_LOG_RX_BUFFERS))
#define RX_RING_MOD_MASK                (RX_RING_SIZE - 1)

#define PKT_BUF_SZ              1536
#define RX_BUFF_SIZE            PKT_BUF_SZ
#define TX_BUFF_SIZE            PKT_BUF_SZ

#undef TEST_HITS
#define ZERO 0

/*
 * The DS2100/3100 have a linear 64 kB buffer which supports halfword
 * accesses only.  Each halfword of the buffer is word-aligned in the
 * CPU address space.
 *
 * The PMAD-AA has a 128 kB buffer on-board.
 *
 * The IOASIC LANCE devices use a shared memory region.  This region
 * as seen from the CPU is (max) 128 kB long and has to be on an 128 kB
 * boundary.  The LANCE sees this as a 64 kB long continuous memory
 * region.
 *
 * The LANCE's DMA address is used as an index in this buffer and DMA
 * takes place in bursts of eight 16-bit words which are packed into
 * four 32-bit words by the IOASIC.  This leads to a strange padding:
 * 16 bytes of valid data followed by a 16 byte gap :-(.
 */

struct lance_rx_desc {
        unsigned short rmd0;            /* low address of packet */
        unsigned short rmd1;            /* high address of packet
                                           and descriptor bits */
        short length;                   /* 2s complement (negative!)
                                           of buffer length */
        unsigned short mblength;        /* actual number of bytes received */
};

struct lance_tx_desc {
        unsigned short tmd0;            /* low address of packet */
        unsigned short tmd1;            /* high address of packet
                                           and descriptor bits */
        short length;                   /* 2s complement (negative!)
                                           of buffer length */
        unsigned short misc;
};


/* First part of the LANCE initialization block, described in databook. */
struct lance_init_block {
        unsigned short mode;            /* pre-set mode (reg. 15) */

        unsigned short phys_addr[3];    /* physical ethernet address */
        unsigned short filter[4];       /* multicast filter */

        /* Receive and transmit ring base, along with extra bits. */
        unsigned short rx_ptr;          /* receive descriptor addr */
        unsigned short rx_len;          /* receive len and high addr */
        unsigned short tx_ptr;          /* transmit descriptor addr */
        unsigned short tx_len;          /* transmit len and high addr */

        short gap[4];

        /* The buffer descriptors */
        struct lance_rx_desc brx_ring[RX_RING_SIZE];
        struct lance_tx_desc btx_ring[TX_RING_SIZE];
};

#define BUF_OFFSET_CPU sizeof(struct lance_init_block)
#define BUF_OFFSET_LNC sizeof(struct lance_init_block)

#define shift_off(off, type)                                            \
        (type == ASIC_LANCE || type == PMAX_LANCE ? off << 1 : off)

#define lib_off(rt, type)                                               \
        shift_off(offsetof(struct lance_init_block, rt), type)

#define lib_ptr(ib, rt, type)                                           \
        ((volatile u16 *)((u8 *)(ib) + lib_off(rt, type)))

#define rds_off(rt, type)                                               \
        shift_off(offsetof(struct lance_rx_desc, rt), type)

#define rds_ptr(rd, rt, type)                                           \
        ((volatile u16 *)((u8 *)(rd) + rds_off(rt, type)))

#define tds_off(rt, type)                                               \
        shift_off(offsetof(struct lance_tx_desc, rt), type)

#define tds_ptr(td, rt, type)                                           \
        ((volatile u16 *)((u8 *)(td) + tds_off(rt, type)))

struct lance_private {
        struct net_device *next;
        int type;
        int dma_irq;
        volatile struct lance_regs *ll;

        spinlock_t      lock;

        int rx_new, tx_new;
        int rx_old, tx_old;

        unsigned short busmaster_regval;

        struct timer_list       multicast_timer;

        /* Pointers to the ring buffers as seen from the CPU */
        char *rx_buf_ptr_cpu[RX_RING_SIZE];
        char *tx_buf_ptr_cpu[TX_RING_SIZE];

        /* Pointers to the ring buffers as seen from the LANCE */
        uint rx_buf_ptr_lnc[RX_RING_SIZE];
        uint tx_buf_ptr_lnc[TX_RING_SIZE];
};

#define TX_BUFFS_AVAIL ((lp->tx_old<=lp->tx_new)?\
                        lp->tx_old+TX_RING_MOD_MASK-lp->tx_new:\
                        lp->tx_old - lp->tx_new-1)

/* The lance control ports are at an absolute address, machine and tc-slot
 * dependent.
 * DECstations do only 32-bit access and the LANCE uses 16 bit addresses,
 * so we have to give the structure an extra member making rap pointing
 * at the right address
 */
struct lance_regs {
        volatile unsigned short rdp;    /* register data port */
        unsigned short pad;
        volatile unsigned short rap;    /* register address port */
};

int dec_lance_debug = 2;

static struct tc_driver dec_lance_tc_driver;
static struct net_device *root_lance_dev;

static inline void writereg(volatile unsigned short *regptr, short value)
{
        *regptr = value;
        iob();
}

/* Load the CSR registers */
static void load_csrs(struct lance_private *lp)
{
        volatile struct lance_regs *ll = lp->ll;
        uint leptr;

        /* The address space as seen from the LANCE
         * begins at address 0. HK
         */
        leptr = 0;

        writereg(&ll->rap, LE_CSR1);
        writereg(&ll->rdp, (leptr & 0xFFFF));
        writereg(&ll->rap, LE_CSR2);
        writereg(&ll->rdp, leptr >> 16);
        writereg(&ll->rap, LE_CSR3);
        writereg(&ll->rdp, lp->busmaster_regval);

        /* Point back to csr0 */
        writereg(&ll->rap, LE_CSR0);
}

/*
 * Our specialized copy routines
 *
 */
static void cp_to_buf(const int type, void *to, const void *from, int len)
{
        unsigned short *tp, *fp, clen;
        unsigned char *rtp, *rfp;

        if (type == PMAD_LANCE) {
                memcpy(to, from, len);
        } else if (type == PMAX_LANCE) {
                clen = len >> 1;
                tp = (unsigned short *) to;
                fp = (unsigned short *) from;

                while (clen--) {
                        *tp++ = *fp++;
                        tp++;
                }

                clen = len & 1;
                rtp = (unsigned char *) tp;
                rfp = (unsigned char *) fp;
                while (clen--) {
                        *rtp++ = *rfp++;
                }
        } else {
                /*
                 * copy 16 Byte chunks
                 */
                clen = len >> 4;
                tp = (unsigned short *) to;
                fp = (unsigned short *) from;
                while (clen--) {
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        tp += 8;
                }

                /*
                 * do the rest, if any.
                 */
                clen = len & 15;
                rtp = (unsigned char *) tp;
                rfp = (unsigned char *) fp;
                while (clen--) {
                        *rtp++ = *rfp++;
                }
        }

        iob();
}

static void cp_from_buf(const int type, void *to, const void *from, int len)
{
        unsigned short *tp, *fp, clen;
        unsigned char *rtp, *rfp;

        if (type == PMAD_LANCE) {
                memcpy(to, from, len);
        } else if (type == PMAX_LANCE) {
                clen = len >> 1;
                tp = (unsigned short *) to;
                fp = (unsigned short *) from;
                while (clen--) {
                        *tp++ = *fp++;
                        fp++;
                }

                clen = len & 1;

                rtp = (unsigned char *) tp;
                rfp = (unsigned char *) fp;

                while (clen--) {
                        *rtp++ = *rfp++;
                }
        } else {

                /*
                 * copy 16 Byte chunks
                 */
                clen = len >> 4;
                tp = (unsigned short *) to;
                fp = (unsigned short *) from;
                while (clen--) {
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        *tp++ = *fp++;
                        fp += 8;
                }

                /*
                 * do the rest, if any.
                 */
                clen = len & 15;
                rtp = (unsigned char *) tp;
                rfp = (unsigned char *) fp;
                while (clen--) {
                        *rtp++ = *rfp++;
                }


        }

}

/* Setup the Lance Rx and Tx rings */
static void lance_init_ring(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        uint leptr;
        int i;

        /* Lock out other processes while setting up hardware */
        netif_stop_queue(dev);
        lp->rx_new = lp->tx_new = 0;
        lp->rx_old = lp->tx_old = 0;

        /* Copy the ethernet address to the lance init block.
         * XXX bit 0 of the physical address registers has to be zero
         */
        *lib_ptr(ib, phys_addr[0], lp->type) = (dev->dev_addr[1] << 8) |
                                     dev->dev_addr[0];
        *lib_ptr(ib, phys_addr[1], lp->type) = (dev->dev_addr[3] << 8) |
                                     dev->dev_addr[2];
        *lib_ptr(ib, phys_addr[2], lp->type) = (dev->dev_addr[5] << 8) |
                                     dev->dev_addr[4];
        /* Setup the initialization block */

        /* Setup rx descriptor pointer */
        leptr = offsetof(struct lance_init_block, brx_ring);
        *lib_ptr(ib, rx_len, lp->type) = (LANCE_LOG_RX_BUFFERS << 13) |
                                         (leptr >> 16);
        *lib_ptr(ib, rx_ptr, lp->type) = leptr;
        if (ZERO)
                printk("RX ptr: %8.8x(%8.8x)\n",
                       leptr, lib_off(brx_ring, lp->type));

        /* Setup tx descriptor pointer */
        leptr = offsetof(struct lance_init_block, btx_ring);
        *lib_ptr(ib, tx_len, lp->type) = (LANCE_LOG_TX_BUFFERS << 13) |
                                         (leptr >> 16);
        *lib_ptr(ib, tx_ptr, lp->type) = leptr;
        if (ZERO)
                printk("TX ptr: %8.8x(%8.8x)\n",
                       leptr, lib_off(btx_ring, lp->type));

        if (ZERO)
                printk("TX rings:\n");

        /* Setup the Tx ring entries */
        for (i = 0; i < TX_RING_SIZE; i++) {
                leptr = lp->tx_buf_ptr_lnc[i];
                *lib_ptr(ib, btx_ring[i].tmd0, lp->type) = leptr;
                *lib_ptr(ib, btx_ring[i].tmd1, lp->type) = (leptr >> 16) &
                                                           0xff;
                *lib_ptr(ib, btx_ring[i].length, lp->type) = 0xf000;
                                                /* The ones required by tmd2 */
                *lib_ptr(ib, btx_ring[i].misc, lp->type) = 0;
                if (i < 3 && ZERO)
                        printk("%d: 0x%8.8x(0x%8.8x)\n",
                               i, leptr, (uint)lp->tx_buf_ptr_cpu[i]);
        }

        /* Setup the Rx ring entries */
        if (ZERO)
                printk("RX rings:\n");
        for (i = 0; i < RX_RING_SIZE; i++) {
                leptr = lp->rx_buf_ptr_lnc[i];
                *lib_ptr(ib, brx_ring[i].rmd0, lp->type) = leptr;
                *lib_ptr(ib, brx_ring[i].rmd1, lp->type) = ((leptr >> 16) &
                                                            0xff) |
                                                           LE_R1_OWN;
                *lib_ptr(ib, brx_ring[i].length, lp->type) = -RX_BUFF_SIZE |
                                                             0xf000;
                *lib_ptr(ib, brx_ring[i].mblength, lp->type) = 0;
                if (i < 3 && ZERO)
                        printk("%d: 0x%8.8x(0x%8.8x)\n",
                               i, leptr, (uint)lp->rx_buf_ptr_cpu[i]);
        }
        iob();
}

static int init_restart_lance(struct lance_private *lp)
{
        volatile struct lance_regs *ll = lp->ll;
        int i;

        writereg(&ll->rap, LE_CSR0);
        writereg(&ll->rdp, LE_C0_INIT);

        /* Wait for the lance to complete initialization */
        for (i = 0; (i < 100) && !(ll->rdp & LE_C0_IDON); i++) {
                udelay(10);
        }
        if ((i == 100) || (ll->rdp & LE_C0_ERR)) {
                printk("LANCE unopened after %d ticks, csr0=%4.4x.\n",
                       i, ll->rdp);
                return -1;
        }
        if ((ll->rdp & LE_C0_ERR)) {
                printk("LANCE unopened after %d ticks, csr0=%4.4x.\n",
                       i, ll->rdp);
                return -1;
        }
        writereg(&ll->rdp, LE_C0_IDON);
        writereg(&ll->rdp, LE_C0_STRT);
        writereg(&ll->rdp, LE_C0_INEA);

        return 0;
}

static int lance_rx(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        volatile u16 *rd;
        unsigned short bits;
        int entry, len;
        struct sk_buff *skb;

#ifdef TEST_HITS
        {
                int i;

                printk("[");
                for (i = 0; i < RX_RING_SIZE; i++) {
                        if (i == lp->rx_new)
                                printk("%s", *lib_ptr(ib, brx_ring[i].rmd1,
                                                      lp->type) &
                                             LE_R1_OWN ? "_" : "X");
                        else
                                printk("%s", *lib_ptr(ib, brx_ring[i].rmd1,
                                                      lp->type) &
                                             LE_R1_OWN ? "." : "1");
                }
                printk("]");
        }
#endif

        for (rd = lib_ptr(ib, brx_ring[lp->rx_new], lp->type);
             !((bits = *rds_ptr(rd, rmd1, lp->type)) & LE_R1_OWN);
             rd = lib_ptr(ib, brx_ring[lp->rx_new], lp->type)) {
                entry = lp->rx_new;

                /* We got an incomplete frame? */
                if ((bits & LE_R1_POK) != LE_R1_POK) {
                        dev->stats.rx_over_errors++;
                        dev->stats.rx_errors++;
                } else if (bits & LE_R1_ERR) {
                        /* Count only the end frame as a rx error,
                         * not the beginning
                         */
                        if (bits & LE_R1_BUF)
                                dev->stats.rx_fifo_errors++;
                        if (bits & LE_R1_CRC)
                                dev->stats.rx_crc_errors++;
                        if (bits & LE_R1_OFL)
                                dev->stats.rx_over_errors++;
                        if (bits & LE_R1_FRA)
                                dev->stats.rx_frame_errors++;
                        if (bits & LE_R1_EOP)
                                dev->stats.rx_errors++;
                } else {
                        len = (*rds_ptr(rd, mblength, lp->type) & 0xfff) - 4;
                        skb = dev_alloc_skb(len + 2);

                        if (skb == 0) {
                                printk("%s: Memory squeeze, deferring packet.\n",
                                       dev->name);
                                dev->stats.rx_dropped++;
                                *rds_ptr(rd, mblength, lp->type) = 0;
                                *rds_ptr(rd, rmd1, lp->type) =
                                        ((lp->rx_buf_ptr_lnc[entry] >> 16) &
                                         0xff) | LE_R1_OWN;
                                lp->rx_new = (entry + 1) & RX_RING_MOD_MASK;
                                return 0;
                        }
                        dev->stats.rx_bytes += len;

                        skb_reserve(skb, 2);    /* 16 byte align */
                        skb_put(skb, len);      /* make room */

                        cp_from_buf(lp->type, skb->data,
                                    (char *)lp->rx_buf_ptr_cpu[entry], len);

                        skb->protocol = eth_type_trans(skb, dev);
                        netif_rx(skb);
                        dev->stats.rx_packets++;
                }

                /* Return the packet to the pool */
                *rds_ptr(rd, mblength, lp->type) = 0;
                *rds_ptr(rd, length, lp->type) = -RX_BUFF_SIZE | 0xf000;
                *rds_ptr(rd, rmd1, lp->type) =
                        ((lp->rx_buf_ptr_lnc[entry] >> 16) & 0xff) | LE_R1_OWN;
                lp->rx_new = (entry + 1) & RX_RING_MOD_MASK;
        }
        return 0;
}

static void lance_tx(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        volatile struct lance_regs *ll = lp->ll;
        volatile u16 *td;
        int i, j;
        int status;

        j = lp->tx_old;

        spin_lock(&lp->lock);

        for (i = j; i != lp->tx_new; i = j) {
                td = lib_ptr(ib, btx_ring[i], lp->type);
                /* If we hit a packet not owned by us, stop */
                if (*tds_ptr(td, tmd1, lp->type) & LE_T1_OWN)
                        break;

                if (*tds_ptr(td, tmd1, lp->type) & LE_T1_ERR) {
                        status = *tds_ptr(td, misc, lp->type);

                        dev->stats.tx_errors++;
                        if (status & LE_T3_RTY)
                                dev->stats.tx_aborted_errors++;
                        if (status & LE_T3_LCOL)
                                dev->stats.tx_window_errors++;

                        if (status & LE_T3_CLOS) {
                                dev->stats.tx_carrier_errors++;
                                printk("%s: Carrier Lost\n", dev->name);
                                /* Stop the lance */
                                writereg(&ll->rap, LE_CSR0);
                                writereg(&ll->rdp, LE_C0_STOP);
                                lance_init_ring(dev);
                                load_csrs(lp);
                                init_restart_lance(lp);
                                goto out;
                        }
                        /* Buffer errors and underflows turn off the
                         * transmitter, restart the adapter.
                         */
                        if (status & (LE_T3_BUF | LE_T3_UFL)) {
                                dev->stats.tx_fifo_errors++;

                                printk("%s: Tx: ERR_BUF|ERR_UFL, restarting\n",
                                       dev->name);
                                /* Stop the lance */
                                writereg(&ll->rap, LE_CSR0);
                                writereg(&ll->rdp, LE_C0_STOP);
                                lance_init_ring(dev);
                                load_csrs(lp);
                                init_restart_lance(lp);
                                goto out;
                        }
                } else if ((*tds_ptr(td, tmd1, lp->type) & LE_T1_POK) ==
                           LE_T1_POK) {
                        /*
                         * So we don't count the packet more than once.
                         */
                        *tds_ptr(td, tmd1, lp->type) &= ~(LE_T1_POK);

                        /* One collision before packet was sent. */
                        if (*tds_ptr(td, tmd1, lp->type) & LE_T1_EONE)
                                dev->stats.collisions++;

                        /* More than one collision, be optimistic. */
                        if (*tds_ptr(td, tmd1, lp->type) & LE_T1_EMORE)
                                dev->stats.collisions += 2;

                        dev->stats.tx_packets++;
                }
                j = (j + 1) & TX_RING_MOD_MASK;
        }
        lp->tx_old = j;
out:
        if (netif_queue_stopped(dev) &&
            TX_BUFFS_AVAIL > 0)
                netif_wake_queue(dev);

        spin_unlock(&lp->lock);
}

static irqreturn_t lance_dma_merr_int(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;

        printk(KERN_ERR "%s: DMA error\n", dev->name);
        return IRQ_HANDLED;
}

static irqreturn_t lance_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        struct lance_private *lp = netdev_priv(dev);
        volatile struct lance_regs *ll = lp->ll;
        int csr0;

        writereg(&ll->rap, LE_CSR0);
        csr0 = ll->rdp;

        /* Acknowledge all the interrupt sources ASAP */
        writereg(&ll->rdp, csr0 & (LE_C0_INTR | LE_C0_TINT | LE_C0_RINT));

        if ((csr0 & LE_C0_ERR)) {
                /* Clear the error condition */
                writereg(&ll->rdp, LE_C0_BABL | LE_C0_ERR | LE_C0_MISS |
                         LE_C0_CERR | LE_C0_MERR);
        }
        if (csr0 & LE_C0_RINT)
                lance_rx(dev);

        if (csr0 & LE_C0_TINT)
                lance_tx(dev);

        if (csr0 & LE_C0_BABL)
                dev->stats.tx_errors++;

        if (csr0 & LE_C0_MISS)
                dev->stats.rx_errors++;

        if (csr0 & LE_C0_MERR) {
                printk("%s: Memory error, status %04x\n", dev->name, csr0);

                writereg(&ll->rdp, LE_C0_STOP);

                lance_init_ring(dev);
                load_csrs(lp);
                init_restart_lance(lp);
                netif_wake_queue(dev);
        }

        writereg(&ll->rdp, LE_C0_INEA);
        writereg(&ll->rdp, LE_C0_INEA);
        return IRQ_HANDLED;
}

static int lance_open(struct net_device *dev)
{
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        struct lance_private *lp = netdev_priv(dev);
        volatile struct lance_regs *ll = lp->ll;
        int status = 0;

        /* Stop the Lance */
        writereg(&ll->rap, LE_CSR0);
        writereg(&ll->rdp, LE_C0_STOP);

        /* Set mode and clear multicast filter only at device open,
         * so that lance_init_ring() called at any error will not
         * forget multicast filters.
         *
         * BTW it is common bug in all lance drivers! --ANK
         */
        *lib_ptr(ib, mode, lp->type) = 0;
        *lib_ptr(ib, filter[0], lp->type) = 0;
        *lib_ptr(ib, filter[1], lp->type) = 0;
        *lib_ptr(ib, filter[2], lp->type) = 0;
        *lib_ptr(ib, filter[3], lp->type) = 0;

        lance_init_ring(dev);
        load_csrs(lp);

        netif_start_queue(dev);

        /* Associate IRQ with lance_interrupt */
        if (request_irq(dev->irq, &lance_interrupt, 0, "lance", dev)) {
                printk("%s: Can't get IRQ %d\n", dev->name, dev->irq);
                return -EAGAIN;
        }
        if (lp->dma_irq >= 0) {
                unsigned long flags;

                if (request_irq(lp->dma_irq, &lance_dma_merr_int, 0,
                                "lance error", dev)) {
                        free_irq(dev->irq, dev);
                        printk("%s: Can't get DMA IRQ %d\n", dev->name,
                                lp->dma_irq);
                        return -EAGAIN;
                }

                spin_lock_irqsave(&ioasic_ssr_lock, flags);

                fast_mb();
                /* Enable I/O ASIC LANCE DMA.  */
                ioasic_write(IO_REG_SSR,
                             ioasic_read(IO_REG_SSR) | IO_SSR_LANCE_DMA_EN);

                fast_mb();
                spin_unlock_irqrestore(&ioasic_ssr_lock, flags);
        }

        status = init_restart_lance(lp);
        return status;
}

static int lance_close(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile struct lance_regs *ll = lp->ll;

        netif_stop_queue(dev);
        del_timer_sync(&lp->multicast_timer);

        /* Stop the card */
        writereg(&ll->rap, LE_CSR0);
        writereg(&ll->rdp, LE_C0_STOP);

        if (lp->dma_irq >= 0) {
                unsigned long flags;

                spin_lock_irqsave(&ioasic_ssr_lock, flags);

                fast_mb();
                /* Disable I/O ASIC LANCE DMA.  */
                ioasic_write(IO_REG_SSR,
                             ioasic_read(IO_REG_SSR) & ~IO_SSR_LANCE_DMA_EN);

                fast_iob();
                spin_unlock_irqrestore(&ioasic_ssr_lock, flags);

                free_irq(lp->dma_irq, dev);
        }
        free_irq(dev->irq, dev);
        return 0;
}

static inline int lance_reset(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile struct lance_regs *ll = lp->ll;
        int status;

        /* Stop the lance */
        writereg(&ll->rap, LE_CSR0);
        writereg(&ll->rdp, LE_C0_STOP);

        lance_init_ring(dev);
        load_csrs(lp);
        dev->trans_start = jiffies;
        status = init_restart_lance(lp);
        return status;
}

static void lance_tx_timeout(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile struct lance_regs *ll = lp->ll;

        printk(KERN_ERR "%s: transmit timed out, status %04x, reset\n",
                dev->name, ll->rdp);
        lance_reset(dev);
        netif_wake_queue(dev);
}

static int lance_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile struct lance_regs *ll = lp->ll;
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        unsigned long flags;
        int entry, len;

        len = skb->len;

        if (len < ETH_ZLEN) {
                if (skb_padto(skb, ETH_ZLEN))
                        return NETDEV_TX_OK;
                len = ETH_ZLEN;
        }

        dev->stats.tx_bytes += len;

        spin_lock_irqsave(&lp->lock, flags);

        entry = lp->tx_new;
        *lib_ptr(ib, btx_ring[entry].length, lp->type) = (-len);
        *lib_ptr(ib, btx_ring[entry].misc, lp->type) = 0;

        cp_to_buf(lp->type, (char *)lp->tx_buf_ptr_cpu[entry], skb->data, len);

        /* Now, give the packet to the lance */
        *lib_ptr(ib, btx_ring[entry].tmd1, lp->type) =
                ((lp->tx_buf_ptr_lnc[entry] >> 16) & 0xff) |
                (LE_T1_POK | LE_T1_OWN);
        lp->tx_new = (entry + 1) & TX_RING_MOD_MASK;

        if (TX_BUFFS_AVAIL <= 0)
                netif_stop_queue(dev);

        /* Kick the lance: transmit now */
        writereg(&ll->rdp, LE_C0_INEA | LE_C0_TDMD);

        spin_unlock_irqrestore(&lp->lock, flags);

        dev->trans_start = jiffies;
        dev_kfree_skb(skb);

        return NETDEV_TX_OK;
}

static void lance_load_multicast(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        struct dev_mc_list *dmi = dev->mc_list;
        char *addrs;
        int i;
        u32 crc;

        /* set all multicast bits */
        if (dev->flags & IFF_ALLMULTI) {
                *lib_ptr(ib, filter[0], lp->type) = 0xffff;
                *lib_ptr(ib, filter[1], lp->type) = 0xffff;
                *lib_ptr(ib, filter[2], lp->type) = 0xffff;
                *lib_ptr(ib, filter[3], lp->type) = 0xffff;
                return;
        }
        /* clear the multicast filter */
        *lib_ptr(ib, filter[0], lp->type) = 0;
        *lib_ptr(ib, filter[1], lp->type) = 0;
        *lib_ptr(ib, filter[2], lp->type) = 0;
        *lib_ptr(ib, filter[3], lp->type) = 0;

        /* Add addresses */
        for (i = 0; i < dev->mc_count; i++) {
                addrs = dmi->dmi_addr;
                dmi = dmi->next;

                /* multicast address? */
                if (!(*addrs & 1))
                        continue;

                crc = ether_crc_le(ETH_ALEN, addrs);
                crc = crc >> 26;
                *lib_ptr(ib, filter[crc >> 4], lp->type) |= 1 << (crc & 0xf);
        }
        return;
}

static void lance_set_multicast(struct net_device *dev)
{
        struct lance_private *lp = netdev_priv(dev);
        volatile u16 *ib = (volatile u16 *)dev->mem_start;
        volatile struct lance_regs *ll = lp->ll;

        if (!netif_running(dev))
                return;

        if (lp->tx_old != lp->tx_new) {
                mod_timer(&lp->multicast_timer, jiffies + 4 * HZ/100);
                netif_wake_queue(dev);
                return;
        }

        netif_stop_queue(dev);

        writereg(&ll->rap, LE_CSR0);
        writereg(&ll->rdp, LE_C0_STOP);

        lance_init_ring(dev);

        if (dev->flags & IFF_PROMISC) {

                *lib_ptr(ib, mode, lp->type) |= LE_MO_PROM;
        } else {
                *lib_ptr(ib, mode, lp->type) &= ~LE_MO_PROM;
                lance_load_multicast(dev);
        }
        load_csrs(lp);
        init_restart_lance(lp);
        netif_wake_queue(dev);
}

static void lance_set_multicast_retry(unsigned long _opaque)
{
        struct net_device *dev = (struct net_device *) _opaque;

        lance_set_multicast(dev);
}

static const struct net_device_ops lance_netdev_ops = {
        .ndo_open               = lance_open,
        .ndo_stop               = lance_close,
        .ndo_start_xmit         = lance_start_xmit,
        .ndo_tx_timeout         = lance_tx_timeout,
        .ndo_set_multicast_list = lance_set_multicast,
        .ndo_change_mtu         = eth_change_mtu,
        .ndo_validate_addr      = eth_validate_addr,
        .ndo_set_mac_address    = eth_mac_addr,
};

static int __init dec_lance_probe(struct device *bdev, const int type)
{
        static unsigned version_printed;
        static const char fmt[] = "declance%d";
        char name[10];
        struct net_device *dev;
        struct lance_private *lp;
        volatile struct lance_regs *ll;
        resource_size_t start = 0, len = 0;
        int i, ret;
        unsigned long esar_base;
        unsigned char *esar;

        if (dec_lance_debug && version_printed++ == 0)
                printk(version);

        if (bdev)
                snprintf(name, sizeof(name), "%s", dev_name(bdev));
        else {
                i = 0;
                dev = root_lance_dev;
                while (dev) {
                        i++;
                        lp = netdev_priv(dev);
                        dev = lp->next;
                }
                snprintf(name, sizeof(name), fmt, i);
        }

        dev = alloc_etherdev(sizeof(struct lance_private));
        if (!dev) {
                printk(KERN_ERR "%s: Unable to allocate etherdev, aborting.\n",
                        name);
                ret = -ENOMEM;
                goto err_out;
        }

        /*
         * alloc_etherdev ensures the data structures used by the LANCE
         * are aligned.
         */
        lp = netdev_priv(dev);
        spin_lock_init(&lp->lock);

        lp->type = type;
        switch (type) {
        case ASIC_LANCE:
                dev->base_addr = CKSEG1ADDR(dec_kn_slot_base + IOASIC_LANCE);

                /* buffer space for the on-board LANCE shared memory */
                /*
                 * FIXME: ugly hack!
                 */
                dev->mem_start = CKSEG1ADDR(0x00020000);
                dev->mem_end = dev->mem_start + 0x00020000;
                dev->irq = dec_interrupt[DEC_IRQ_LANCE];
                esar_base = CKSEG1ADDR(dec_kn_slot_base + IOASIC_ESAR);

                /* Workaround crash with booting KN04 2.1k from Disk */
                memset((void *)dev->mem_start, 0,
                       dev->mem_end - dev->mem_start);

                /*
                 * setup the pointer arrays, this sucks [tm] :-(
                 */
                for (i = 0; i < RX_RING_SIZE; i++) {
                        lp->rx_buf_ptr_cpu[i] =
                                (char *)(dev->mem_start + 2 * BUF_OFFSET_CPU +
                                         2 * i * RX_BUFF_SIZE);
                        lp->rx_buf_ptr_lnc[i] =
                                (BUF_OFFSET_LNC + i * RX_BUFF_SIZE);
                }
                for (i = 0; i < TX_RING_SIZE; i++) {
                        lp->tx_buf_ptr_cpu[i] =
                                (char *)(dev->mem_start + 2 * BUF_OFFSET_CPU +
                                         2 * RX_RING_SIZE * RX_BUFF_SIZE +
                                         2 * i * TX_BUFF_SIZE);
                        lp->tx_buf_ptr_lnc[i] =
                                (BUF_OFFSET_LNC +
                                 RX_RING_SIZE * RX_BUFF_SIZE +
                                 i * TX_BUFF_SIZE);
                }

                /* Setup I/O ASIC LANCE DMA.  */
                lp->dma_irq = dec_interrupt[DEC_IRQ_LANCE_MERR];
                ioasic_write(IO_REG_LANCE_DMA_P,
                             CPHYSADDR(dev->mem_start) << 3);

                break;
#ifdef CONFIG_TC
        case PMAD_LANCE:
                dev_set_drvdata(bdev, dev);

                start = to_tc_dev(bdev)->resource.start;
                len = to_tc_dev(bdev)->resource.end - start + 1;
                if (!request_mem_region(start, len, dev_name(bdev))) {
                        printk(KERN_ERR
                               "%s: Unable to reserve MMIO resource\n",
                               dev_name(bdev));
                        ret = -EBUSY;
                        goto err_out_dev;
                }

                dev->mem_start = CKSEG1ADDR(start);
                dev->mem_end = dev->mem_start + 0x100000;
                dev->base_addr = dev->mem_start + 0x100000;
                dev->irq = to_tc_dev(bdev)->interrupt;
                esar_base = dev->mem_start + 0x1c0002;
                lp->dma_irq = -1;

                for (i = 0; i < RX_RING_SIZE; i++) {
                        lp->rx_buf_ptr_cpu[i] =
                                (char *)(dev->mem_start + BUF_OFFSET_CPU +
                                         i * RX_BUFF_SIZE);
                        lp->rx_buf_ptr_lnc[i] =
                                (BUF_OFFSET_LNC + i * RX_BUFF_SIZE);
                }
                for (i = 0; i < TX_RING_SIZE; i++) {
                        lp->tx_buf_ptr_cpu[i] =
                                (char *)(dev->mem_start + BUF_OFFSET_CPU +
                                         RX_RING_SIZE * RX_BUFF_SIZE +
                                         i * TX_BUFF_SIZE);
                        lp->tx_buf_ptr_lnc[i] =
                                (BUF_OFFSET_LNC +
                                 RX_RING_SIZE * RX_BUFF_SIZE +
                                 i * TX_BUFF_SIZE);
                }

                break;
#endif
        case PMAX_LANCE:
                dev->irq = dec_interrupt[DEC_IRQ_LANCE];
                dev->base_addr = CKSEG1ADDR(KN01_SLOT_BASE + KN01_LANCE);
                dev->mem_start = CKSEG1ADDR(KN01_SLOT_BASE + KN01_LANCE_MEM);
                dev->mem_end = dev->mem_start + KN01_SLOT_SIZE;
                esar_base = CKSEG1ADDR(KN01_SLOT_BASE + KN01_ESAR + 1);
                lp->dma_irq = -1;

                /*
                 * setup the pointer arrays, this sucks [tm] :-(
                 */
                for (i = 0; i < RX_RING_SIZE; i++) {
                        lp->rx_buf_ptr_cpu[i] =
                                (char *)(dev->mem_start + 2 * BUF_OFFSET_CPU +
                                         2 * i * RX_BUFF_SIZE);
                        lp->rx_buf_ptr_lnc[i] =
                                (BUF_OFFSET_LNC + i * RX_BUFF_SIZE);
                }
                for (i = 0; i < TX_RING_SIZE; i++) {
                        lp->tx_buf_ptr_cpu[i] =
                                (char *)(dev->mem_start + 2 * BUF_OFFSET_CPU +
                                         2 * RX_RING_SIZE * RX_BUFF_SIZE +
                                         2 * i * TX_BUFF_SIZE);
                        lp->tx_buf_ptr_lnc[i] =
                                (BUF_OFFSET_LNC +
                                 RX_RING_SIZE * RX_BUFF_SIZE +
                                 i * TX_BUFF_SIZE);
                }

                break;

        default:
                printk(KERN_ERR "%s: declance_init called with unknown type\n",
                        name);
                ret = -ENODEV;
                goto err_out_dev;
        }

        ll = (struct lance_regs *) dev->base_addr;
        esar = (unsigned char *) esar_base;

        /* prom checks */
        /* First, check for test pattern */
        if (esar[0x60] != 0xff && esar[0x64] != 0x00 &&
            esar[0x68] != 0x55 && esar[0x6c] != 0xaa) {
                printk(KERN_ERR
                        "%s: Ethernet station address prom not found!\n",
                        name);
                ret = -ENODEV;
                goto err_out_resource;
        }
        /* Check the prom contents */
        for (i = 0; i < 8; i++) {
                if (esar[i * 4] != esar[0x3c - i * 4] &&
                    esar[i * 4] != esar[0x40 + i * 4] &&
                    esar[0x3c - i * 4] != esar[0x40 + i * 4]) {
                        printk(KERN_ERR "%s: Something is wrong with the "
                                "ethernet station address prom!\n", name);
                        ret = -ENODEV;
                        goto err_out_resource;
                }
        }

        /* Copy the ethernet address to the device structure, later to the
         * lance initialization block so the lance gets it every time it's
         * (re)initialized.
         */
        switch (type) {
        case ASIC_LANCE:
                printk("%s: IOASIC onboard LANCE", name);
                break;
        case PMAD_LANCE:
                printk("%s: PMAD-AA", name);
                break;
        case PMAX_LANCE:
                printk("%s: PMAX onboard LANCE", name);
                break;
        }
        for (i = 0; i < 6; i++)
                dev->dev_addr[i] = esar[i * 4];

        printk(", addr = %pM, irq = %d\n", dev->dev_addr, dev->irq);

        dev->netdev_ops = &lance_netdev_ops;
        dev->watchdog_timeo = 5*HZ;

        /* lp->ll is the location of the registers for lance card */
        lp->ll = ll;

        /* busmaster_regval (CSR3) should be zero according to the PMAD-AA
         * specification.
         */
        lp->busmaster_regval = 0;

        dev->dma = 0;

        /* We cannot sleep if the chip is busy during a
         * multicast list update event, because such events
         * can occur from interrupts (ex. IPv6).  So we
         * use a timer to try again later when necessary. -DaveM
         */
        init_timer(&lp->multicast_timer);
        lp->multicast_timer.data = (unsigned long) dev;
        lp->multicast_timer.function = &lance_set_multicast_retry;

        ret = register_netdev(dev);
        if (ret) {
                printk(KERN_ERR
                        "%s: Unable to register netdev, aborting.\n", name);
                goto err_out_resource;
        }

        if (!bdev) {
                lp->next = root_lance_dev;
                root_lance_dev = dev;
        }

        printk("%s: registered as %s.\n", name, dev->name);
        return 0;

err_out_resource:
        if (bdev)
                release_mem_region(start, len);

err_out_dev:
        free_netdev(dev);

err_out:
        return ret;
}

static void __exit dec_lance_remove(struct device *bdev)
{
        struct net_device *dev = dev_get_drvdata(bdev);
        resource_size_t start, len;

        unregister_netdev(dev);
        start = to_tc_dev(bdev)->resource.start;
        len = to_tc_dev(bdev)->resource.end - start + 1;
        release_mem_region(start, len);
        free_netdev(dev);
}

/* Find all the lance cards on the system and initialize them */
static int __init dec_lance_platform_probe(void)
{
        int count = 0;

        if (dec_interrupt[DEC_IRQ_LANCE] >= 0) {
                if (dec_interrupt[DEC_IRQ_LANCE_MERR] >= 0) {
                        if (dec_lance_probe(NULL, ASIC_LANCE) >= 0)
                                count++;
                } else if (!TURBOCHANNEL) {
                        if (dec_lance_probe(NULL, PMAX_LANCE) >= 0)
                                count++;
                }
        }

        return (count > 0) ? 0 : -ENODEV;
}

static void __exit dec_lance_platform_remove(void)
{
        while (root_lance_dev) {
                struct net_device *dev = root_lance_dev;
                struct lance_private *lp = netdev_priv(dev);

                unregister_netdev(dev);
                root_lance_dev = lp->next;
                free_netdev(dev);
        }
}

#ifdef CONFIG_TC
static int __init dec_lance_tc_probe(struct device *dev);
static int __exit dec_lance_tc_remove(struct device *dev);

static const struct tc_device_id dec_lance_tc_table[] = {
        { "DEC     ", "PMAD-AA " },
        { }
};
MODULE_DEVICE_TABLE(tc, dec_lance_tc_table);

static struct tc_driver dec_lance_tc_driver = {
        .id_table       = dec_lance_tc_table,
        .driver         = {
                .name   = "declance",
                .bus    = &tc_bus_type,
                .probe  = dec_lance_tc_probe,
                .remove = __exit_p(dec_lance_tc_remove),
        },
};

static int __init dec_lance_tc_probe(struct device *dev)
{
        int status = dec_lance_probe(dev, PMAD_LANCE);
        if (!status)
                get_device(dev);
        return status;
}

static int __exit dec_lance_tc_remove(struct device *dev)
{
        put_device(dev);
        dec_lance_remove(dev);
        return 0;
}
#endif

static int __init dec_lance_init(void)
{
        int status;

        status = tc_register_driver(&dec_lance_tc_driver);
        if (!status)
                dec_lance_platform_probe();
        return status;
}

static void __exit dec_lance_exit(void)
{
        dec_lance_platform_remove();
        tc_unregister_driver(&dec_lance_tc_driver);
}


module_init(dec_lance_init);
module_exit(dec_lance_exit);