ne2000.c

/*
 * QEMU NE2000 emulation
 * 
 * Copyright (c) 2003-2004 Fabrice Bellard
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
#include "vl.h"

/* debug NE2000 card */
//#define DEBUG_NE2000

#define MAX_ETH_FRAME_SIZE 1514

#define E8390_CMD	0x00  /* The command register (for all pages) */
/* Page 0 register offsets. */
#define EN0_CLDALO	0x01	/* Low byte of current local dma addr  RD */
#define EN0_STARTPG	0x01	/* Starting page of ring bfr WR */
#define EN0_CLDAHI	0x02	/* High byte of current local dma addr  RD */
#define EN0_STOPPG	0x02	/* Ending page +1 of ring bfr WR */
#define EN0_BOUNDARY	0x03	/* Boundary page of ring bfr RD WR */
#define EN0_TSR		0x04	/* Transmit status reg RD */
#define EN0_TPSR	0x04	/* Transmit starting page WR */
#define EN0_NCR		0x05	/* Number of collision reg RD */
#define EN0_TCNTLO	0x05	/* Low  byte of tx byte count WR */
#define EN0_FIFO	0x06	/* FIFO RD */
#define EN0_TCNTHI	0x06	/* High byte of tx byte count WR */
#define EN0_ISR		0x07	/* Interrupt status reg RD WR */
#define EN0_CRDALO	0x08	/* low byte of current remote dma address RD */
#define EN0_RSARLO	0x08	/* Remote start address reg 0 */
#define EN0_CRDAHI	0x09	/* high byte, current remote dma address RD */
#define EN0_RSARHI	0x09	/* Remote start address reg 1 */
#define EN0_RCNTLO	0x0a	/* Remote byte count reg WR */
#define EN0_RCNTHI	0x0b	/* Remote byte count reg WR */
#define EN0_RSR		0x0c	/* rx status reg RD */
#define EN0_RXCR	0x0c	/* RX configuration reg WR */
#define EN0_TXCR	0x0d	/* TX configuration reg WR */
#define EN0_COUNTER0	0x0d	/* Rcv alignment error counter RD */
#define EN0_DCFG	0x0e	/* Data configuration reg WR */
#define EN0_COUNTER1	0x0e	/* Rcv CRC error counter RD */
#define EN0_IMR		0x0f	/* Interrupt mask reg WR */
#define EN0_COUNTER2	0x0f	/* Rcv missed frame error counter RD */

#define EN1_PHYS        0x11
#define EN1_CURPAG      0x17
#define EN1_MULT        0x18

/*  Register accessed at EN_CMD, the 8390 base addr.  */
#define E8390_STOP	0x01	/* Stop and reset the chip */
#define E8390_START	0x02	/* Start the chip, clear reset */
#define E8390_TRANS	0x04	/* Transmit a frame */
#define E8390_RREAD	0x08	/* Remote read */
#define E8390_RWRITE	0x10	/* Remote write  */
#define E8390_NODMA	0x20	/* Remote DMA */
#define E8390_PAGE0	0x00	/* Select page chip registers */
#define E8390_PAGE1	0x40	/* using the two high-order bits */
#define E8390_PAGE2	0x80	/* Page 3 is invalid. */

/* Bits in EN0_ISR - Interrupt status register */
#define ENISR_RX	0x01	/* Receiver, no error */
#define ENISR_TX	0x02	/* Transmitter, no error */
#define ENISR_RX_ERR	0x04	/* Receiver, with error */
#define ENISR_TX_ERR	0x08	/* Transmitter, with error */
#define ENISR_OVER	0x10	/* Receiver overwrote the ring */
#define ENISR_COUNTERS	0x20	/* Counters need emptying */
#define ENISR_RDC	0x40	/* remote dma complete */
#define ENISR_RESET	0x80	/* Reset completed */
#define ENISR_ALL	0x3f	/* Interrupts we will enable */

/* Bits in received packet status byte and EN0_RSR*/
#define ENRSR_RXOK	0x01	/* Received a good packet */
#define ENRSR_CRC	0x02	/* CRC error */
#define ENRSR_FAE	0x04	/* frame alignment error */
#define ENRSR_FO	0x08	/* FIFO overrun */
#define ENRSR_MPA	0x10	/* missed pkt */
#define ENRSR_PHY	0x20	/* physical/multicast address */
#define ENRSR_DIS	0x40	/* receiver disable. set in monitor mode */
#define ENRSR_DEF	0x80	/* deferring */

/* Transmitted packet status, EN0_TSR. */
#define ENTSR_PTX 0x01	/* Packet transmitted without error */
#define ENTSR_ND  0x02	/* The transmit wasn't deferred. */
#define ENTSR_COL 0x04	/* The transmit collided at least once. */
#define ENTSR_ABT 0x08  /* The transmit collided 16 times, and was deferred. */
#define ENTSR_CRS 0x10	/* The carrier sense was lost. */
#define ENTSR_FU  0x20  /* A "FIFO underrun" occurred during transmit. */
#define ENTSR_CDH 0x40	/* The collision detect "heartbeat" signal was lost. */
#define ENTSR_OWC 0x80  /* There was an out-of-window collision. */

#define NE2000_PMEM_SIZE    (32*1024)
#define NE2000_PMEM_START   (16*1024)
#define NE2000_PMEM_END     (NE2000_PMEM_SIZE+NE2000_PMEM_START)
#define NE2000_MEM_SIZE     NE2000_PMEM_END

typedef struct NE2000State {
    uint8_t cmd;
    uint32_t start;
    uint32_t stop;
    uint8_t boundary;
    uint8_t tsr;
    uint8_t tpsr;
    uint16_t tcnt;
    uint16_t rcnt;
    uint32_t rsar;
    uint8_t isr;
    uint8_t dcfg;
    uint8_t imr;
    uint8_t phys[6]; /* mac address */
    uint8_t curpag;
    uint8_t mult[8]; /* multicast mask array */
    int irq;
    NetDriverState *nd;
    uint8_t mem[NE2000_MEM_SIZE];
} NE2000State;

static void ne2000_reset(NE2000State *s)
{
    int i;

    s->isr = ENISR_RESET;
    memcpy(s->mem, s->nd->macaddr, 6);
    s->mem[14] = 0x57;
    s->mem[15] = 0x57;

    /* duplicate prom data */
    for(i = 15;i >= 0; i--) {
        s->mem[2 * i] = s->mem[i];
        s->mem[2 * i + 1] = s->mem[i];
    }
}

static void ne2000_update_irq(NE2000State *s)
{
    int isr;
    isr = s->isr & s->imr;
#if defined(DEBUG_NE2000)
    printf("NE2000: Set IRQ line %d to %d (%02x %02x)\n",
	   s->irq, isr ? 1 : 0, s->isr, s->imr);
#endif
    if (isr)
        pic_set_irq(s->irq, 1);
    else
        pic_set_irq(s->irq, 0);
}

/* return the max buffer size if the NE2000 can receive more data */
static int ne2000_can_receive(void *opaque)
{
    NE2000State *s = opaque;
    int avail, index, boundary;
    
    if (s->cmd & E8390_STOP)
        return 0;
    index = s->curpag << 8;
    boundary = s->boundary << 8;
    if (index < boundary)
        avail = boundary - index;
    else
        avail = (s->stop - s->start) - (index - boundary);
    if (avail < (MAX_ETH_FRAME_SIZE + 4))
        return 0;
    return MAX_ETH_FRAME_SIZE;
}

#define MIN_BUF_SIZE 60

static void ne2000_receive(void *opaque, const uint8_t *buf, int size)
{
    NE2000State *s = opaque;
    uint8_t *p;
    int total_len, next, avail, len, index;
    uint8_t buf1[60];
    
#if defined(DEBUG_NE2000)
    printf("NE2000: received len=%d\n", size);
#endif

    /* if too small buffer, then expand it */
    if (size < MIN_BUF_SIZE) {
        memcpy(buf1, buf, size);
        memset(buf1 + size, 0, MIN_BUF_SIZE - size);
        buf = buf1;
        size = MIN_BUF_SIZE;
    }

    index = s->curpag << 8;
    /* 4 bytes for header */
    total_len = size + 4;
    /* address for next packet (4 bytes for CRC) */
    next = index + ((total_len + 4 + 255) & ~0xff);
    if (next >= s->stop)
        next -= (s->stop - s->start);
    /* prepare packet header */
    p = s->mem + index;
    p[0] = ENRSR_RXOK; /* receive status */
    p[1] = next >> 8;
    p[2] = total_len;
    p[3] = total_len >> 8;
    index += 4;

    /* write packet data */
    while (size > 0) {
        avail = s->stop - index;
        len = size;
        if (len > avail)
            len = avail;
        memcpy(s->mem + index, buf, len);
        buf += len;
        index += len;
        if (index == s->stop)
            index = s->start;
        size -= len;
    }
    s->curpag = next >> 8;
    
    /* now we can signal we have receive something */
    s->isr |= ENISR_RX;
    ne2000_update_irq(s);
}

static void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
    NE2000State *s = opaque;
    int offset, page;

    addr &= 0xf;
#ifdef DEBUG_NE2000
    printf("NE2000: write addr=0x%x val=0x%02x\n", addr, val);
#endif
    if (addr == E8390_CMD) {
        /* control register */
        s->cmd = val;
        if (val & E8390_START) {
            s->isr &= ~ENISR_RESET;
            /* test specific case: zero length transfert */
            if ((val & (E8390_RREAD | E8390_RWRITE)) &&
                s->rcnt == 0) {
                s->isr |= ENISR_RDC;
                ne2000_update_irq(s);
            }
            if (val & E8390_TRANS) {
                qemu_send_packet(s->nd, s->mem + (s->tpsr << 8), s->tcnt);
                /* signal end of transfert */
                s->tsr = ENTSR_PTX;
                s->isr |= ENISR_TX;
                ne2000_update_irq(s);
            }
        }
    } else {
        page = s->cmd >> 6;
        offset = addr | (page << 4);
        switch(offset) {
        case EN0_STARTPG:
            s->start = val << 8;
            break;
        case EN0_STOPPG:
            s->stop = val << 8;
            break;
        case EN0_BOUNDARY:
            s->boundary = val;
            break;
        case EN0_IMR:
            s->imr = val;
            ne2000_update_irq(s);
            break;
        case EN0_TPSR:
            s->tpsr = val;
            break;
        case EN0_TCNTLO:
            s->tcnt = (s->tcnt & 0xff00) | val;
            break;
        case EN0_TCNTHI:
            s->tcnt = (s->tcnt & 0x00ff) | (val << 8);
            break;
        case EN0_RSARLO:
            s->rsar = (s->rsar & 0xff00) | val;
            break;
        case EN0_RSARHI:
            s->rsar = (s->rsar & 0x00ff) | (val << 8);
            break;
        case EN0_RCNTLO:
            s->rcnt = (s->rcnt & 0xff00) | val;
            break;
        case EN0_RCNTHI:
            s->rcnt = (s->rcnt & 0x00ff) | (val << 8);
            break;
        case EN0_DCFG:
            s->dcfg = val;
            break;
        case EN0_ISR:
            s->isr &= ~(val & 0x7f);
            ne2000_update_irq(s);
            break;
        case EN1_PHYS ... EN1_PHYS + 5:
            s->phys[offset - EN1_PHYS] = val;
            break;
        case EN1_CURPAG:
            s->curpag = val;
            break;
        case EN1_MULT ... EN1_MULT + 7:
            s->mult[offset - EN1_MULT] = val;
            break;
        }
    }
}

static uint32_t ne2000_ioport_read(void *opaque, uint32_t addr)
{
    NE2000State *s = opaque;
    int offset, page, ret;

    addr &= 0xf;
    if (addr == E8390_CMD) {
        ret = s->cmd;
    } else {
        page = s->cmd >> 6;
        offset = addr | (page << 4);
        switch(offset) {
        case EN0_TSR:
            ret = s->tsr;
            break;
        case EN0_BOUNDARY:
            ret = s->boundary;
            break;
        case EN0_ISR:
            ret = s->isr;
            break;
	case EN0_RSARLO:
	    ret = s->rsar & 0x00ff;
	    break;
	case EN0_RSARHI:
	    ret = s->rsar >> 8;
	    break;
        case EN1_PHYS ... EN1_PHYS + 5:
            ret = s->phys[offset - EN1_PHYS];
            break;
        case EN1_CURPAG:
            ret = s->curpag;
            break;
        case EN1_MULT ... EN1_MULT + 7:
            ret = s->mult[offset - EN1_MULT];
            break;
        default:
            ret = 0x00;
            break;
        }
    }
#ifdef DEBUG_NE2000
    printf("NE2000: read addr=0x%x val=%02x\n", addr, ret);
#endif
    return ret;
}

static inline void ne2000_mem_writeb(NE2000State *s, uint32_t addr, 
                                    uint32_t val)
{
    if (addr < 32 || 
        (addr >= NE2000_PMEM_START && addr < NE2000_MEM_SIZE)) {
        s->mem[addr] = val;
    }
}

static inline void ne2000_mem_writew(NE2000State *s, uint32_t addr, 
                                     uint32_t val)
{
    addr &= ~1; /* XXX: check exact behaviour if not even */
    if (addr < 32 || 
        (addr >= NE2000_PMEM_START && addr < NE2000_MEM_SIZE)) {
        s->mem[addr] = val;
        s->mem[addr + 1] = val >> 8;
    }
}

static inline uint32_t ne2000_mem_readb(NE2000State *s, uint32_t addr)
{
    if (addr < 32 || 
        (addr >= NE2000_PMEM_START && addr < NE2000_MEM_SIZE)) {
        return s->mem[addr];
    } else {
        return 0xff;
    }
}

static inline uint32_t ne2000_mem_readw(NE2000State *s, uint32_t addr)
{
    addr &= ~1; /* XXX: check exact behaviour if not even */
    if (addr < 32 || 
        (addr >= NE2000_PMEM_START && addr < NE2000_MEM_SIZE)) {
        return s->mem[addr] | (s->mem[addr + 1] << 8);
    } else {
        return 0xffff;
    }
}

static void ne2000_asic_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
    NE2000State *s = opaque;

#ifdef DEBUG_NE2000
    printf("NE2000: asic write val=0x%04x\n", val);
#endif
    if (s->rcnt == 0)
	    return;
    if (s->dcfg & 0x01) {
        /* 16 bit access */
        ne2000_mem_writew(s, s->rsar, val);
        s->rsar += 2;
        s->rcnt -= 2;
    } else {
        /* 8 bit access */
        ne2000_mem_writeb(s, s->rsar, val);
        s->rsar++;
        s->rcnt--;
    }
    /* wrap */
    if (s->rsar == s->stop)
        s->rsar = s->start;
    if (s->rcnt == 0) {
        /* signal end of transfert */
        s->isr |= ENISR_RDC;
        ne2000_update_irq(s);
    }
}

static uint32_t ne2000_asic_ioport_read(void *opaque, uint32_t addr)
{
    NE2000State *s = opaque;
    int ret;

    if (s->dcfg & 0x01) {
        /* 16 bit access */
        ret = ne2000_mem_readw(s, s->rsar);
        s->rsar += 2;
        s->rcnt -= 2;
    } else {
        /* 8 bit access */
        ret = ne2000_mem_readb(s, s->rsar);
        s->rsar++;
        s->rcnt--;
    }
    /* wrap */
    if (s->rsar == s->stop)
        s->rsar = s->start;
    if (s->rcnt == 0) {
        /* signal end of transfert */
        s->isr |= ENISR_RDC;
        ne2000_update_irq(s);
    }
#ifdef DEBUG_NE2000
    printf("NE2000: asic read val=0x%04x\n", ret);
#endif
    return ret;
}

static void ne2000_reset_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
    /* nothing to do (end of reset pulse) */
}

static uint32_t ne2000_reset_ioport_read(void *opaque, uint32_t addr)
{
    NE2000State *s = opaque;
    ne2000_reset(s);
    return 0;
}

void ne2000_init(int base, int irq, NetDriverState *nd)
{
    NE2000State *s;

    s = qemu_mallocz(sizeof(NE2000State));
    if (!s)
        return;
    
    register_ioport_write(base, 16, 1, ne2000_ioport_write, s);
    register_ioport_read(base, 16, 1, ne2000_ioport_read, s);

    register_ioport_write(base + 0x10, 1, 1, ne2000_asic_ioport_write, s);
    register_ioport_read(base + 0x10, 1, 1, ne2000_asic_ioport_read, s);
    register_ioport_write(base + 0x10, 2, 2, ne2000_asic_ioport_write, s);
    register_ioport_read(base + 0x10, 2, 2, ne2000_asic_ioport_read, s);

    register_ioport_write(base + 0x1f, 1, 1, ne2000_reset_ioport_write, s);
    register_ioport_read(base + 0x1f, 1, 1, ne2000_reset_ioport_read, s);
    s->irq = irq;
    s->nd = nd;

    ne2000_reset(s);

    qemu_add_read_packet(nd, ne2000_can_receive, ne2000_receive, s);
}