Archipelago » qemu

/*

 * QEMU i8255x (PRO100) emulation

 *

 * Copyright (c) 2006-2007 Stefan Weil

 *

 * Portions of the code are copies from grub / etherboot eepro100.c

 * and linux e100.c.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, see <http://www.gnu.org/licenses/>.

 *

 * Tested features (i82559):

 *      PXE boot (i386) no valid link

 *      Linux networking (i386) ok

 *

 * Untested:

 *      non-i386 platforms

 *      Windows networking

 *

 * References:

 *

 * Intel 8255x 10/100 Mbps Ethernet Controller Family

 * Open Source Software Developer Manual

 */

#if defined(TARGET_I386)

# warning "PXE boot still not working!"

#endif

#include <stddef.h>             /* offsetof */

#include <stdbool.h>

#include "hw.h"

#include "pci.h"

#include "net.h"

#include "eeprom93xx.h"

/* Common declarations for all PCI devices. */

#define PCI_CONFIG_8(offset, value) \

    (pci_conf[offset] = (value))

#define PCI_CONFIG_16(offset, value) \

    (*(uint16_t *)&pci_conf[offset] = cpu_to_le16(value))

#define PCI_CONFIG_32(offset, value) \

    (*(uint32_t *)&pci_conf[offset] = cpu_to_le32(value))

#define KiB 1024

/* Debug EEPRO100 card. */

//~ #define DEBUG_EEPRO100

#ifdef DEBUG_EEPRO100

#define logout(fmt, ...) fprintf(stderr, "EE100\t%-24s" fmt, __func__, ## __VA_ARGS__)

#else

#define logout(fmt, ...) ((void)0)

#endif

/* Set flags to 0 to disable debug output. */

#define INT     1       /* interrupt related actions */

#define MDI     1       /* mdi related actions */

#define OTHER   1

#define RXTX    1

#define EEPROM  1       /* eeprom related actions */

#define TRACE(flag, command) ((flag) ? (command) : (void)0)

#define missing(text) fprintf(stderr, "eepro100: feature is missing in this emulation: " text "\n")

#define MAX_ETH_FRAME_SIZE 1514

/* This driver supports several different devices which are declared here. */

#define i82550          0x82550

#define i82551          0x82551

#define i82557A         0x82557a

#define i82557B         0x82557b

#define i82557C         0x82557c

#define i82558A         0x82558a

#define i82558B         0x82558b

#define i82559A         0x82559a

#define i82559B         0x82559b

#define i82559C         0x82559c

#define i82559ER        0x82559e

#define i82562          0x82562

/* Use 64 word EEPROM. TODO: could be a runtime option. */

#define EEPROM_SIZE     64

#define PCI_MEM_SIZE            (4 * KiB)

#define PCI_IO_SIZE             64

#define PCI_FLASH_SIZE          (128 * KiB)

#define BIT(n) (1 << (n))

#define BITS(n, m) (((0xffffffffU << (31 - n)) >> (31 - n + m)) << m)

/* The SCB accepts the following controls for the Tx and Rx units: */

#define  CU_NOP         0x0000  /* No operation. */

#define  CU_START       0x0010  /* CU start. */

#define  CU_RESUME      0x0020  /* CU resume. */

#define  CU_STATSADDR   0x0040  /* Load dump counters address. */

#define  CU_SHOWSTATS   0x0050  /* Dump statistical counters. */

#define  CU_CMD_BASE    0x0060  /* Load CU base address. */

#define  CU_DUMPSTATS   0x0070  /* Dump and reset statistical counters. */

#define  CU_SRESUME     0x00a0  /* CU static resume. */

#define  RU_NOP         0x0000

#define  RX_START       0x0001

#define  RX_RESUME      0x0002

#define  RX_ABORT       0x0004

#define  RX_ADDR_LOAD   0x0006

#define  RX_RESUMENR    0x0007

#define INT_MASK        0x0100

#define DRVR_INT        0x0200  /* Driver generated interrupt. */

/* Offsets to the various registers.

   All accesses need not be longword aligned. */

enum speedo_offsets {

    SCBStatus = 0,

    SCBAck = 1,

    SCBCmd = 2,                 /* Rx/Command Unit command and status. */

    SCBIntmask = 3,

    SCBPointer = 4,             /* General purpose pointer. */

    SCBPort = 8,                /* Misc. commands and operands.  */

    SCBflash = 12, SCBeeprom = 14,      /* EEPROM and flash memory control. */

    SCBCtrlMDI = 16,            /* MDI interface control. */

    SCBEarlyRx = 20,            /* Early receive byte count. */

    SCBFlow = 24,

};

/* A speedo3 transmit buffer descriptor with two buffers... */

typedef struct {

    uint16_t status;

    uint16_t command;

    uint32_t link;              /* void * */

    uint32_t tx_desc_addr;      /* transmit buffer decsriptor array address. */

    uint16_t tcb_bytes;         /* transmit command block byte count (in lower 14 bits */

    uint8_t tx_threshold;       /* transmit threshold */

    uint8_t tbd_count;          /* TBD number */

    //~ /* This constitutes two "TBD" entries: hdr and data */

    //~ uint32_t tx_buf_addr0;  /* void *, header of frame to be transmitted.  */

    //~ int32_t  tx_buf_size0;  /* Length of Tx hdr. */

    //~ uint32_t tx_buf_addr1;  /* void *, data to be transmitted.  */

    //~ int32_t  tx_buf_size1;  /* Length of Tx data. */

} eepro100_tx_t;

/* Receive frame descriptor. */

typedef struct {

    int16_t status;

    uint16_t command;

    uint32_t link;              /* struct RxFD * */

    uint32_t rx_buf_addr;       /* void * */

    uint16_t count;

    uint16_t size;

    char packet[MAX_ETH_FRAME_SIZE + 4];

} eepro100_rx_t;

typedef struct {

    uint32_t tx_good_frames, tx_max_collisions, tx_late_collisions,

        tx_underruns, tx_lost_crs, tx_deferred, tx_single_collisions,

        tx_multiple_collisions, tx_total_collisions;

    uint32_t rx_good_frames, rx_crc_errors, rx_alignment_errors,

        rx_resource_errors, rx_overrun_errors, rx_cdt_errors,

        rx_short_frame_errors;

    uint32_t fc_xmt_pause, fc_rcv_pause, fc_rcv_unsupported;

    uint16_t xmt_tco_frames, rcv_tco_frames;

    uint32_t complete;

} eepro100_stats_t;

typedef enum {

    cu_idle = 0,

    cu_suspended = 1,

    cu_active = 2,

    cu_lpq_active = 2,

    cu_hqp_active = 3

} cu_state_t;

typedef enum {

    ru_idle = 0,

    ru_suspended = 1,

    ru_no_resources = 2,

    ru_ready = 4

} ru_state_t;

typedef struct {

    PCIDevice dev;

    uint8_t mult[8];            /* multicast mask array */

    int mmio_index;

    VLANClientState *vc;

    uint8_t scb_stat;           /* SCB stat/ack byte */

    uint8_t int_stat;           /* PCI interrupt status */

    /* region must not be saved by nic_save. */

    uint32_t region[3];         /* PCI region addresses */

    uint8_t macaddr[6];

    uint16_t mdimem[32];

    eeprom_t *eeprom;

    uint32_t device;            /* device variant */

    uint32_t pointer;

    /* (cu_base + cu_offset) address the next command block in the command block list. */

    uint32_t cu_base;           /* CU base address */

    uint32_t cu_offset;         /* CU address offset */

    /* (ru_base + ru_offset) address the RFD in the Receive Frame Area. */

    uint32_t ru_base;           /* RU base address */

    uint32_t ru_offset;         /* RU address offset */

    uint32_t statsaddr;         /* pointer to eepro100_stats_t */

    eepro100_stats_t statistics;        /* statistical counters */

#if 0

    uint16_t status;

#endif

    /* Configuration bytes. */

    uint8_t configuration[22];

    /* Data in mem is always in the byte order of the controller (le). */

    uint8_t mem[PCI_MEM_SIZE];

} EEPRO100State;

/* Default values for MDI (PHY) registers */

static const uint16_t eepro100_mdi_default[] = {

    /* MDI Registers 0 - 6, 7 */

    0x3000, 0x780d, 0x02a8, 0x0154, 0x05e1, 0x0000, 0x0000, 0x0000,

    /* MDI Registers 8 - 15 */

    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

    /* MDI Registers 16 - 31 */

    0x0003, 0x0000, 0x0001, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

};

/* Readonly mask for MDI (PHY) registers */

static const uint16_t eepro100_mdi_mask[] = {

    0x0000, 0xffff, 0xffff, 0xffff, 0xc01f, 0xffff, 0xffff, 0x0000,

    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

    0x0fff, 0x0000, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff,

    0xffff, 0xffff, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,

};

#define POLYNOMIAL 0x04c11db6

/* From FreeBSD */

/* XXX: optimize */

static int compute_mcast_idx(const uint8_t * ep)

{

    uint32_t crc;

    int carry, i, j;

    uint8_t b;

    crc = 0xffffffff;

    for (i = 0; i < 6; i++) {

        b = *ep++;

        for (j = 0; j < 8; j++) {

            carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);

            crc <<= 1;

            b >>= 1;

            if (carry) {

                crc = ((crc ^ POLYNOMIAL) | carry);

            }

        }

    }

    return (crc >> 26);

}

#if defined(DEBUG_EEPRO100)

static const char *nic_dump(const uint8_t * buf, unsigned size)

{

    static char dump[3 * 16 + 1];

    char *p = &dump[0];

    if (size > 16) {

        size = 16;

    }

    while (size-- > 0) {

        p += sprintf(p, " %02x", *buf++);

    }

    return dump;

}

#endif                          /* DEBUG_EEPRO100 */

enum scb_stat_ack {

    stat_ack_not_ours = 0x00,

    stat_ack_sw_gen = 0x04,

    stat_ack_rnr = 0x10,

    stat_ack_cu_idle = 0x20,

    stat_ack_frame_rx = 0x40,

    stat_ack_cu_cmd_done = 0x80,

    stat_ack_not_present = 0xFF,

    stat_ack_rx = (stat_ack_sw_gen | stat_ack_rnr | stat_ack_frame_rx),

    stat_ack_tx = (stat_ack_cu_idle | stat_ack_cu_cmd_done),

};

static void disable_interrupt(EEPRO100State * s)

{

    if (s->int_stat) {

        TRACE(INT, logout("interrupt disabled\n"));

        qemu_irq_lower(s->dev.irq[0]);

        s->int_stat = 0;

    }

}

static void enable_interrupt(EEPRO100State * s)

{

    if (!s->int_stat) {

        TRACE(INT, logout("interrupt enabled\n"));

        qemu_irq_raise(s->dev.irq[0]);

        s->int_stat = 1;

    }

}

static void eepro100_acknowledge(EEPRO100State * s)

{

    s->scb_stat &= ~s->mem[SCBAck];

    s->mem[SCBAck] = s->scb_stat;

    if (s->scb_stat == 0) {

        disable_interrupt(s);

    }

}

static void eepro100_interrupt(EEPRO100State * s, uint8_t stat)

{

    uint8_t mask = ~s->mem[SCBIntmask];

    s->mem[SCBAck] |= stat;

    stat = s->scb_stat = s->mem[SCBAck];

    stat &= (mask | 0x0f);

    //~ stat &= (~s->mem[SCBIntmask] | 0x0xf);

    if (stat && (mask & 0x01)) {

        /* SCB mask and SCB Bit M do not disable interrupt. */

        enable_interrupt(s);

    } else if (s->int_stat) {

        disable_interrupt(s);

    }

}

static void eepro100_cx_interrupt(EEPRO100State * s)

{

    /* CU completed action command. */

    /* Transmit not ok (82557 only, not in emulation). */

    eepro100_interrupt(s, 0x80);

}

static void eepro100_cna_interrupt(EEPRO100State * s)

{

    /* CU left the active state. */

    eepro100_interrupt(s, 0x20);

}

static void eepro100_fr_interrupt(EEPRO100State * s)

{

    /* RU received a complete frame. */

    eepro100_interrupt(s, 0x40);

}

#if 0

static void eepro100_rnr_interrupt(EEPRO100State * s)

{

    /* RU is not ready. */

    eepro100_interrupt(s, 0x10);

}

#endif

static void eepro100_mdi_interrupt(EEPRO100State * s)

{

    /* MDI completed read or write cycle. */

    eepro100_interrupt(s, 0x08);

}

static void eepro100_swi_interrupt(EEPRO100State * s)

{

    /* Software has requested an interrupt. */

    eepro100_interrupt(s, 0x04);

}

#if 0

static void eepro100_fcp_interrupt(EEPRO100State * s)

{

    /* Flow control pause interrupt (82558 and later). */

    eepro100_interrupt(s, 0x01);

}

#endif

static void pci_reset(EEPRO100State * s)

{

    uint32_t device = s->device;

    uint8_t *pci_conf = s->dev.config;

    TRACE(OTHER, logout("%p\n", s));

    /* PCI Vendor ID */

    pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_INTEL);

    /* PCI Device ID depends on device and is set below. */

    /* PCI Command */

    PCI_CONFIG_16(PCI_COMMAND, 0x0000);

    /* PCI Status */

    PCI_CONFIG_16(PCI_STATUS, 0x2800);

    /* PCI Revision ID */

    PCI_CONFIG_8(PCI_REVISION_ID, 0x08);

    /* PCI Class Code */

    PCI_CONFIG_8(0x09, 0x00);

    pci_config_set_class(pci_conf, PCI_CLASS_NETWORK_ETHERNET);

    /* PCI Cache Line Size */

    /* check cache line size!!! */

    //~ PCI_CONFIG_8(0x0c, 0x00);

    /* PCI Latency Timer */

    PCI_CONFIG_8(0x0d, 0x20);   // latency timer = 32 clocks

    /* PCI Header Type */

    /* BIST (built-in self test) */

#if defined(TARGET_I386)

// !!! workaround for buggy bios

//~ #define PCI_ADDRESS_SPACE_MEM_PREFETCH 0

#endif

#if 0

    /* PCI Base Address Registers */

    /* CSR Memory Mapped Base Address */

    PCI_CONFIG_32(PCI_BASE_ADDRESS_0,

                  PCI_ADDRESS_SPACE_MEM | PCI_ADDRESS_SPACE_MEM_PREFETCH);

    /* CSR I/O Mapped Base Address */

    PCI_CONFIG_32(PCI_BASE_ADDRESS_1, PCI_ADDRESS_SPACE_IO);

#if 0

    /* Flash Memory Mapped Base Address */

    PCI_CONFIG_32(PCI_BASE_ADDRESS_2, 0xfffe0000 | PCI_ADDRESS_SPACE_MEM);

#endif

#endif

    /* Expansion ROM Base Address (depends on boot disable!!!) */

    PCI_CONFIG_32(0x30, 0x00000000);

    /* Capability Pointer */

    PCI_CONFIG_8(0x34, 0xdc);

    /* Interrupt Line */

    /* Interrupt Pin */

    PCI_CONFIG_8(0x3d, 1);      // interrupt pin 0

    /* Minimum Grant */

    PCI_CONFIG_8(0x3e, 0x08);

    /* Maximum Latency */

    PCI_CONFIG_8(0x3f, 0x18);

    /* Power Management Capabilities / Next Item Pointer / Capability ID */

    PCI_CONFIG_32(0xdc, 0x7e210001);

    switch (device) {

    case i82551:

        pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82551IT);

        PCI_CONFIG_8(PCI_REVISION_ID, 0x0f);

        break;

    case i82557B:

        pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82557);

        PCI_CONFIG_8(PCI_REVISION_ID, 0x02);

        break;

    case i82557C:

        pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82557);

        PCI_CONFIG_8(PCI_REVISION_ID, 0x03);

        break;

    case i82558B:

        pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82557);

        PCI_CONFIG_16(PCI_STATUS, 0x2810);

        PCI_CONFIG_8(PCI_REVISION_ID, 0x05);

        break;

    case i82559C:

        pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82557);

        PCI_CONFIG_16(PCI_STATUS, 0x2810);

        //~ PCI_CONFIG_8(PCI_REVISION_ID, 0x08);

        break;

    case i82559ER:

        pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82551IT);

        PCI_CONFIG_16(PCI_STATUS, 0x2810);

        PCI_CONFIG_8(PCI_REVISION_ID, 0x09);

        break;

    //~ PCI_CONFIG_16(PCI_DEVICE_ID, 0x1029);

    //~ PCI_CONFIG_16(PCI_DEVICE_ID, 0x1030);       /* 82559 InBusiness 10/100 */

    default:

        logout("Device %X is undefined!\n", device);

    }

    if (device == i82557C || device == i82558B || device == i82559C) {

        logout("Get device id and revision from EEPROM!!!\n");

    }

}

static void nic_selective_reset(EEPRO100State * s)

{

    size_t i;

    uint16_t *eeprom_contents = eeprom93xx_data(s->eeprom);

    //~ eeprom93xx_reset(s->eeprom);

    memcpy(eeprom_contents, s->macaddr, 6);

    eeprom_contents[0xa] = 0x4000;

    if (s->device == i82557B || s->device == i82557C)

        eeprom_contents[5] = 0x0100;

    uint16_t sum = 0;

    for (i = 0; i < EEPROM_SIZE - 1; i++) {

        sum += eeprom_contents[i];

    }

    eeprom_contents[EEPROM_SIZE - 1] = 0xbaba - sum;

    TRACE(EEPROM, logout("checksum=0x%04x\n", eeprom_contents[EEPROM_SIZE - 1]));

    memset(s->mem, 0, sizeof(s->mem));

    uint32_t val = BIT(21);

    memcpy(&s->mem[SCBCtrlMDI], &val, sizeof(val));

    assert(sizeof(s->mdimem) == sizeof(eepro100_mdi_default));

    memcpy(&s->mdimem[0], &eepro100_mdi_default[0], sizeof(s->mdimem));

}

static void nic_reset(void *opaque)

{

    EEPRO100State *s = opaque;

    TRACE(OTHER, logout("%p\n", s));

    nic_selective_reset(s);

}

#if defined(DEBUG_EEPRO100)

static const char * const reg[PCI_IO_SIZE / 4] = {

    "Command/Status",

    "General Pointer",

    "Port",

    "EEPROM/Flash Control",

    "MDI Control",

    "Receive DMA Byte Count",

    "Flow control",

    "General Status/Control"

};

static char *regname(uint32_t addr)

{

    static char buf[16];

    if (addr < PCI_IO_SIZE) {

        const char *r = reg[addr / 4];

        if (r != 0) {

            snprintf(buf, sizeof(buf), "%s+%u", r, addr % 4);

        } else {

            snprintf(buf, sizeof(buf), "0x%02x", addr);

        }

    } else {

        snprintf(buf, sizeof(buf), "??? 0x%08x", addr);

    }

    return buf;

}

#endif                          /* DEBUG_EEPRO100 */

#if 0

static uint16_t eepro100_read_status(EEPRO100State * s)

{

    uint16_t val = s->status;

    TRACE(OTHER, logout("val=0x%04x\n", val));

    return val;

}

static void eepro100_write_status(EEPRO100State * s, uint16_t val)

{

    TRACE(OTHER, logout("val=0x%04x\n", val));

    s->status = val;

}

#endif

/*****************************************************************************

 *

 * Command emulation.

 *

 ****************************************************************************/

#if 0

static uint16_t eepro100_read_command(EEPRO100State * s)

{

    uint16_t val = 0xffff;

    //~ TRACE(OTHER, logout("val=0x%04x\n", val));

    return val;

}

#endif

static bool device_supports_eTxCB(EEPRO100State * s)

{

    return (s->device != i82557B && s->device != i82557C);

}

/* Commands that can be put in a command list entry. */

enum commands {

    CmdNOp = 0,

    CmdIASetup = 1,

    CmdConfigure = 2,

    CmdMulticastList = 3,

    CmdTx = 4,

    CmdTDR = 5,                 /* load microcode */

    CmdDump = 6,

    CmdDiagnose = 7,

    /* And some extra flags: */

    CmdSuspend = 0x4000,        /* Suspend after completion. */

    CmdIntr = 0x2000,           /* Interrupt after completion. */

    CmdTxFlex = 0x0008,         /* Use "Flexible mode" for CmdTx command. */

};

static cu_state_t get_cu_state(EEPRO100State * s)

{

    return ((s->mem[SCBStatus] >> 6) & 0x03);

}

static void set_cu_state(EEPRO100State * s, cu_state_t state)

{

    s->mem[SCBStatus] = (s->mem[SCBStatus] & 0x3f) + (state << 6);

}

static ru_state_t get_ru_state(EEPRO100State * s)

{

    return ((s->mem[SCBStatus] >> 2) & 0x0f);

}

static void set_ru_state(EEPRO100State * s, ru_state_t state)

{

    s->mem[SCBStatus] = (s->mem[SCBStatus] & 0xc3) + (state << 2);

}

static void dump_statistics(EEPRO100State * s)

{

    /* Dump statistical data. Most data is never changed by the emulation

     * and always 0, so we first just copy the whole block and then those

     * values which really matter.

     * Number of data should check configuration!!!

     */

    cpu_physical_memory_write(s->statsaddr, (uint8_t *) & s->statistics, 64);

    stl_phys(s->statsaddr + 0, s->statistics.tx_good_frames);

    stl_phys(s->statsaddr + 36, s->statistics.rx_good_frames);

    stl_phys(s->statsaddr + 48, s->statistics.rx_resource_errors);

    stl_phys(s->statsaddr + 60, s->statistics.rx_short_frame_errors);

    //~ stw_phys(s->statsaddr + 76, s->statistics.xmt_tco_frames);

    //~ stw_phys(s->statsaddr + 78, s->statistics.rcv_tco_frames);

    //~ missing("CU dump statistical counters");

}

static void eepro100_cu_command(EEPRO100State * s, uint8_t val)

{

    eepro100_tx_t tx;

    uint32_t cb_address;

    switch (val) {

    case CU_NOP:

        /* No operation. */

        break;

    case CU_START:

        if (get_cu_state(s) != cu_idle) {

            /* Intel documentation says that CU must be idle for the CU

             * start command. Intel driver for Linux also starts the CU

             * from suspended state. */

            logout("CU state is %u, should be %u\n", get_cu_state(s), cu_idle);

            //~ assert(!"wrong CU state");

        }

        set_cu_state(s, cu_active);

        s->cu_offset = s->pointer;

      next_command:

        cb_address = s->cu_base + s->cu_offset;

        cpu_physical_memory_read(cb_address, (uint8_t *) & tx, sizeof(tx));

        uint16_t status = le16_to_cpu(tx.status);

        uint16_t command = le16_to_cpu(tx.command);

        logout

            ("val=0x%02x (cu start), status=0x%04x, command=0x%04x, link=0x%08x\n",

             val, status, command, tx.link);

        bool bit_el = ((command & 0x8000) != 0);

        bool bit_s = ((command & 0x4000) != 0);

        bool bit_i = ((command & 0x2000) != 0);

        bool bit_nc = ((command & 0x0010) != 0);

        bool success = true;

        //~ bool bit_sf = ((command & 0x0008) != 0);

        uint16_t cmd = command & 0x0007;

        s->cu_offset = le32_to_cpu(tx.link);

        switch (cmd) {

        case CmdNOp:

            /* Do nothing. */

            break;

        case CmdIASetup:

            cpu_physical_memory_read(cb_address + 8, &s->macaddr[0], 6);

            TRACE(OTHER, logout("macaddr: %s\n", nic_dump(&s->macaddr[0], 6)));

            break;

        case CmdConfigure:

            cpu_physical_memory_read(cb_address + 8, &s->configuration[0],

                                     sizeof(s->configuration));

            TRACE(OTHER, logout("configuration: %s\n", nic_dump(&s->configuration[0], 16)));

            break;

        case CmdMulticastList:

            //~ missing("multicast list");

            break;

        case CmdTx:

            (void)0;

            uint32_t tbd_array = le32_to_cpu(tx.tx_desc_addr);

            uint16_t tcb_bytes = (le16_to_cpu(tx.tcb_bytes) & 0x3fff);

            TRACE(RXTX, logout

                ("transmit, TBD array address 0x%08x, TCB byte count 0x%04x, TBD count %u\n",

                 tbd_array, tcb_bytes, tx.tbd_count));

            if (bit_nc) {

                missing("CmdTx: NC = 0");

                success = false;

                break;

            }

            //~ assert(!bit_sf);

            if (tcb_bytes > 2600) {

                logout("TCB byte count too large, using 2600\n");

                tcb_bytes = 2600;

            }

            /* Next assertion fails for local configuration. */

            //~ assert((tcb_bytes > 0) || (tbd_array != 0xffffffff));

            if (!((tcb_bytes > 0) || (tbd_array != 0xffffffff))) {

                logout

                    ("illegal values of TBD array address and TCB byte count!\n");

            }

            // sends larger than MAX_ETH_FRAME_SIZE are allowed, up to 2600 bytes

            uint8_t buf[2600];

            uint16_t size = 0;

            uint32_t tbd_address = cb_address + 0x10;

            assert(tcb_bytes <= sizeof(buf));

            while (size < tcb_bytes) {

                uint32_t tx_buffer_address = ldl_phys(tbd_address);

                uint16_t tx_buffer_size = lduw_phys(tbd_address + 4);

                //~ uint16_t tx_buffer_el = lduw_phys(tbd_address + 6);

                tbd_address += 8;

                TRACE(RXTX, logout

                    ("TBD (simplified mode): buffer address 0x%08x, size 0x%04x\n",

                     tx_buffer_address, tx_buffer_size));

                tx_buffer_size = MIN(tx_buffer_size, sizeof(buf) - size);

                cpu_physical_memory_read(tx_buffer_address, &buf[size],

                                         tx_buffer_size);

                size += tx_buffer_size;

            }

            if (tbd_array == 0xffffffff) {

                /* Simplified mode. Was already handled by code above. */

            } else {

                /* Flexible mode. */

                uint8_t tbd_count = 0;

                if (device_supports_eTxCB(s) && !(s->configuration[6] & BIT(4))) {

                    /* Extended Flexible TCB. */

                    for (; tbd_count < 2; tbd_count++) {

                        uint32_t tx_buffer_address = ldl_phys(tbd_address);

                        uint16_t tx_buffer_size = lduw_phys(tbd_address + 4);

                        uint16_t tx_buffer_el = lduw_phys(tbd_address + 6);

                        tbd_address += 8;

                        TRACE(RXTX, logout

                            ("TBD (extended flexible mode): buffer address 0x%08x, size 0x%04x\n",

                             tx_buffer_address, tx_buffer_size));

                        tx_buffer_size = MIN(tx_buffer_size, sizeof(buf) - size);

                        cpu_physical_memory_read(tx_buffer_address, &buf[size],

                                                 tx_buffer_size);

                        size += tx_buffer_size;

                        if (tx_buffer_el & 1) {

                            break;

                        }

                    }

                }

                tbd_address = tbd_array;

                for (; tbd_count < tx.tbd_count; tbd_count++) {

                    uint32_t tx_buffer_address = ldl_phys(tbd_address);

                    uint16_t tx_buffer_size = lduw_phys(tbd_address + 4);

                    uint16_t tx_buffer_el = lduw_phys(tbd_address + 6);

                    tbd_address += 8;

                    TRACE(RXTX, logout

                        ("TBD (flexible mode): buffer address 0x%08x, size 0x%04x\n",

                         tx_buffer_address, tx_buffer_size));

                    tx_buffer_size = MIN(tx_buffer_size, sizeof(buf) - size);

                    cpu_physical_memory_read(tx_buffer_address, &buf[size],

                                             tx_buffer_size);

                    size += tx_buffer_size;

                    if (tx_buffer_el & 1) {

                        break;

                    }

                }

            }

            TRACE(RXTX, logout("%p sending frame, len=%d,%s\n", s, size, nic_dump(buf, size)));

            qemu_send_packet(s->vc, buf, size);

            s->statistics.tx_good_frames++;

            /* Transmit with bad status would raise an CX/TNO interrupt.

             * (82557 only). Emulation never has bad status. */

            //~ eepro100_cx_interrupt(s);

            break;

        case CmdTDR:

            TRACE(OTHER, logout("load microcode\n"));

            /* Starting with offset 8, the command contains

             * 64 dwords microcode which we just ignore here. */

            break;

        default:

            missing("undefined command");

            success = false;

            break;

        }

        /* Write new status. */

        stw_phys(cb_address, status | 0x8000 | (success ? 0x2000 : 0));

        if (bit_i) {

            /* CU completed action. */

            eepro100_cx_interrupt(s);

        }

        if (bit_el) {

            /* CU becomes idle. Terminate command loop. */

            set_cu_state(s, cu_idle);

            eepro100_cna_interrupt(s);

        } else if (bit_s) {

            /* CU becomes suspended. */

            set_cu_state(s, cu_suspended);

            eepro100_cna_interrupt(s);

        } else {

            /* More entries in list. */

            TRACE(OTHER, logout("CU list with at least one more entry\n"));

            goto next_command;

        }

        TRACE(OTHER, logout("CU list empty\n"));

        /* List is empty. Now CU is idle or suspended. */

        break;

    case CU_RESUME:

        if (get_cu_state(s) != cu_suspended) {

            logout("bad CU resume from CU state %u\n", get_cu_state(s));

            /* Workaround for bad Linux eepro100 driver which resumes

             * from idle state. */

            //~ missing("cu resume");

            set_cu_state(s, cu_suspended);

        }

        if (get_cu_state(s) == cu_suspended) {

            TRACE(OTHER, logout("CU resuming\n"));

            set_cu_state(s, cu_active);

            goto next_command;

        }

        break;

    case CU_STATSADDR:

        /* Load dump counters address. */

        s->statsaddr = s->pointer;

        TRACE(OTHER, logout("val=0x%02x (status address)\n", val));

        break;

    case CU_SHOWSTATS:

        /* Dump statistical counters. */

        TRACE(OTHER, logout("val=0x%02x (dump stats)\n", val));

        dump_statistics(s);

        break;

    case CU_CMD_BASE:

        /* Load CU base. */

        TRACE(OTHER, logout("val=0x%02x (CU base address)\n", val));

        s->cu_base = s->pointer;

        break;

    case CU_DUMPSTATS:

        /* Dump and reset statistical counters. */

        TRACE(OTHER, logout("val=0x%02x (dump stats and reset)\n", val));

        dump_statistics(s);

        memset(&s->statistics, 0, sizeof(s->statistics));

        break;

    case CU_SRESUME:

        /* CU static resume. */

        missing("CU static resume");

        break;

    default:

        missing("Undefined CU command");

    }

}

static void eepro100_ru_command(EEPRO100State * s, uint8_t val)

{

    switch (val) {

    case RU_NOP:

        /* No operation. */

        break;

    case RX_START:

        /* RU start. */

        if (get_ru_state(s) != ru_idle) {

            logout("RU state is %u, should be %u\n", get_ru_state(s), ru_idle);

            //~ assert(!"wrong RU state");

        }

        set_ru_state(s, ru_ready);

        s->ru_offset = s->pointer;

        TRACE(OTHER, logout("val=0x%02x (rx start)\n", val));