Archipelago » qemu

/*

 * QEMU IDE disk and CD/DVD-ROM Emulator

 *

 * Copyright (c) 2003 Fabrice Bellard

 * Copyright (c) 2006 Openedhand Ltd.

 *

 * 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 "hw.h"

#include "pc.h"

#include "pci.h"

#include "scsi-disk.h"

#include "pcmcia.h"

#include "block.h"

#include "qemu-timer.h"

#include "sysemu.h"

#include "ppc_mac.h"

/* debug IDE devices */

//#define DEBUG_IDE

//#define DEBUG_IDE_ATAPI

//#define DEBUG_AIO

#define USE_DMA_CDROM

/* Bits of HD_STATUS */

#define ERR_STAT                0x01

#define INDEX_STAT                0x02

#define ECC_STAT                0x04        /* Corrected error */

#define DRQ_STAT                0x08

#define SEEK_STAT                0x10

#define SRV_STAT                0x10

#define WRERR_STAT                0x20

#define READY_STAT                0x40

#define BUSY_STAT                0x80

/* Bits for HD_ERROR */

#define MARK_ERR                0x01        /* Bad address mark */

#define TRK0_ERR                0x02        /* couldn't find track 0 */

#define ABRT_ERR                0x04        /* Command aborted */

#define MCR_ERR                        0x08        /* media change request */

#define ID_ERR                        0x10        /* ID field not found */

#define MC_ERR                        0x20        /* media changed */

#define ECC_ERR                        0x40        /* Uncorrectable ECC error */

#define BBD_ERR                        0x80        /* pre-EIDE meaning:  block marked bad */

#define ICRC_ERR                0x80        /* new meaning:  CRC error during transfer */

/* Bits of HD_NSECTOR */

#define CD                        0x01

#define IO                        0x02

#define REL                        0x04

#define TAG_MASK                0xf8

#define IDE_CMD_RESET           0x04

#define IDE_CMD_DISABLE_IRQ     0x02

/* ATA/ATAPI Commands pre T13 Spec */

#define WIN_NOP                                0x00

/*

 *        0x01->0x02 Reserved

 */

#define CFA_REQ_EXT_ERROR_CODE                0x03 /* CFA Request Extended Error Code */

/*

 *        0x04->0x07 Reserved

 */

#define WIN_SRST                        0x08 /* ATAPI soft reset command */

#define WIN_DEVICE_RESET                0x08

/*

 *        0x09->0x0F Reserved

 */

#define WIN_RECAL                        0x10

#define WIN_RESTORE                        WIN_RECAL

/*

 *        0x10->0x1F Reserved

 */

#define WIN_READ                        0x20 /* 28-Bit */

#define WIN_READ_ONCE                        0x21 /* 28-Bit without retries */

#define WIN_READ_LONG                        0x22 /* 28-Bit */

#define WIN_READ_LONG_ONCE                0x23 /* 28-Bit without retries */

#define WIN_READ_EXT                        0x24 /* 48-Bit */

#define WIN_READDMA_EXT                        0x25 /* 48-Bit */

#define WIN_READDMA_QUEUED_EXT                0x26 /* 48-Bit */

#define WIN_READ_NATIVE_MAX_EXT                0x27 /* 48-Bit */

/*

 *        0x28

 */

#define WIN_MULTREAD_EXT                0x29 /* 48-Bit */

/*

 *        0x2A->0x2F Reserved

 */

#define WIN_WRITE                        0x30 /* 28-Bit */

#define WIN_WRITE_ONCE                        0x31 /* 28-Bit without retries */

#define WIN_WRITE_LONG                        0x32 /* 28-Bit */

#define WIN_WRITE_LONG_ONCE                0x33 /* 28-Bit without retries */

#define WIN_WRITE_EXT                        0x34 /* 48-Bit */

#define WIN_WRITEDMA_EXT                0x35 /* 48-Bit */

#define WIN_WRITEDMA_QUEUED_EXT                0x36 /* 48-Bit */

#define WIN_SET_MAX_EXT                        0x37 /* 48-Bit */

#define CFA_WRITE_SECT_WO_ERASE                0x38 /* CFA Write Sectors without erase */

#define WIN_MULTWRITE_EXT                0x39 /* 48-Bit */

/*

 *        0x3A->0x3B Reserved

 */

#define WIN_WRITE_VERIFY                0x3C /* 28-Bit */

/*

 *        0x3D->0x3F Reserved

 */

#define WIN_VERIFY                        0x40 /* 28-Bit - Read Verify Sectors */

#define WIN_VERIFY_ONCE                        0x41 /* 28-Bit - without retries */

#define WIN_VERIFY_EXT                        0x42 /* 48-Bit */

/*

 *        0x43->0x4F Reserved

 */

#define WIN_FORMAT                        0x50

/*

 *        0x51->0x5F Reserved

 */

#define WIN_INIT                        0x60

/*

 *        0x61->0x5F Reserved

 */

#define WIN_SEEK                        0x70 /* 0x70-0x7F Reserved */

#define CFA_TRANSLATE_SECTOR                0x87 /* CFA Translate Sector */

#define WIN_DIAGNOSE                        0x90

#define WIN_SPECIFY                        0x91 /* set drive geometry translation */

#define WIN_DOWNLOAD_MICROCODE                0x92

#define WIN_STANDBYNOW2                        0x94

#define CFA_IDLEIMMEDIATE                0x95 /* force drive to become "ready" */

#define WIN_STANDBY2                        0x96

#define WIN_SETIDLE2                        0x97

#define WIN_CHECKPOWERMODE2                0x98

#define WIN_SLEEPNOW2                        0x99

/*

 *        0x9A VENDOR

 */

#define WIN_PACKETCMD                        0xA0 /* Send a packet command. */

#define WIN_PIDENTIFY                        0xA1 /* identify ATAPI device        */

#define WIN_QUEUED_SERVICE                0xA2

#define WIN_SMART                        0xB0 /* self-monitoring and reporting */

#define CFA_ACCESS_METADATA_STORAGE        0xB8

#define CFA_ERASE_SECTORS               0xC0 /* microdrives implement as NOP */

#define WIN_MULTREAD                        0xC4 /* read sectors using multiple mode*/

#define WIN_MULTWRITE                        0xC5 /* write sectors using multiple mode */

#define WIN_SETMULT                        0xC6 /* enable/disable multiple mode */

#define WIN_READDMA_QUEUED                0xC7 /* read sectors using Queued DMA transfers */

#define WIN_READDMA                        0xC8 /* read sectors using DMA transfers */

#define WIN_READDMA_ONCE                0xC9 /* 28-Bit - without retries */

#define WIN_WRITEDMA                        0xCA /* write sectors using DMA transfers */

#define WIN_WRITEDMA_ONCE                0xCB /* 28-Bit - without retries */

#define WIN_WRITEDMA_QUEUED                0xCC /* write sectors using Queued DMA transfers */

#define CFA_WRITE_MULTI_WO_ERASE        0xCD /* CFA Write multiple without erase */

#define WIN_GETMEDIASTATUS                0xDA

#define WIN_ACKMEDIACHANGE                0xDB /* ATA-1, ATA-2 vendor */

#define WIN_POSTBOOT                        0xDC

#define WIN_PREBOOT                        0xDD

#define WIN_DOORLOCK                        0xDE /* lock door on removable drives */

#define WIN_DOORUNLOCK                        0xDF /* unlock door on removable drives */

#define WIN_STANDBYNOW1                        0xE0

#define WIN_IDLEIMMEDIATE                0xE1 /* force drive to become "ready" */

#define WIN_STANDBY                     0xE2 /* Set device in Standby Mode */

#define WIN_SETIDLE1                        0xE3

#define WIN_READ_BUFFER                        0xE4 /* force read only 1 sector */

#define WIN_CHECKPOWERMODE1                0xE5

#define WIN_SLEEPNOW1                        0xE6

#define WIN_FLUSH_CACHE                        0xE7

#define WIN_WRITE_BUFFER                0xE8 /* force write only 1 sector */

#define WIN_WRITE_SAME                        0xE9 /* read ata-2 to use */

        /* SET_FEATURES 0x22 or 0xDD */

#define WIN_FLUSH_CACHE_EXT                0xEA /* 48-Bit */

#define WIN_IDENTIFY                        0xEC /* ask drive to identify itself        */

#define WIN_MEDIAEJECT                        0xED

#define WIN_IDENTIFY_DMA                0xEE /* same as WIN_IDENTIFY, but DMA */

#define WIN_SETFEATURES                        0xEF /* set special drive features */

#define EXABYTE_ENABLE_NEST                0xF0

#define IBM_SENSE_CONDITION                0xF0 /* measure disk temperature */

#define WIN_SECURITY_SET_PASS                0xF1

#define WIN_SECURITY_UNLOCK                0xF2

#define WIN_SECURITY_ERASE_PREPARE        0xF3

#define WIN_SECURITY_ERASE_UNIT                0xF4

#define WIN_SECURITY_FREEZE_LOCK        0xF5

#define CFA_WEAR_LEVEL                        0xF5 /* microdrives implement as NOP */

#define WIN_SECURITY_DISABLE                0xF6

#define WIN_READ_NATIVE_MAX                0xF8 /* return the native maximum address */

#define WIN_SET_MAX                        0xF9

#define DISABLE_SEAGATE                        0xFB

/* set to 1 set disable mult support */

#define MAX_MULT_SECTORS 16

#define IDE_DMA_BUF_SECTORS 256

#if (IDE_DMA_BUF_SECTORS < MAX_MULT_SECTORS)

#error "IDE_DMA_BUF_SECTORS must be bigger or equal to MAX_MULT_SECTORS"

#endif

/* ATAPI defines */

#define ATAPI_PACKET_SIZE 12

/* The generic packet command opcodes for CD/DVD Logical Units,

 * From Table 57 of the SFF8090 Ver. 3 (Mt. Fuji) draft standard. */

#define GPCMD_BLANK                            0xa1

#define GPCMD_CLOSE_TRACK                    0x5b

#define GPCMD_FLUSH_CACHE                    0x35

#define GPCMD_FORMAT_UNIT                    0x04

#define GPCMD_GET_CONFIGURATION                    0x46

#define GPCMD_GET_EVENT_STATUS_NOTIFICATION 0x4a

#define GPCMD_GET_PERFORMANCE                    0xac

#define GPCMD_INQUIRY                            0x12

#define GPCMD_LOAD_UNLOAD                    0xa6

#define GPCMD_MECHANISM_STATUS                    0xbd

#define GPCMD_MODE_SELECT_10                    0x55

#define GPCMD_MODE_SENSE_10                    0x5a

#define GPCMD_PAUSE_RESUME                    0x4b

#define GPCMD_PLAY_AUDIO_10                    0x45

#define GPCMD_PLAY_AUDIO_MSF                    0x47

#define GPCMD_PLAY_AUDIO_TI                    0x48

#define GPCMD_PLAY_CD                            0xbc

#define GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL  0x1e

#define GPCMD_READ_10                            0x28

#define GPCMD_READ_12                            0xa8

#define GPCMD_READ_CDVD_CAPACITY            0x25

#define GPCMD_READ_CD                            0xbe

#define GPCMD_READ_CD_MSF                    0xb9

#define GPCMD_READ_DISC_INFO                    0x51

#define GPCMD_READ_DVD_STRUCTURE            0xad

#define GPCMD_READ_FORMAT_CAPACITIES            0x23

#define GPCMD_READ_HEADER                    0x44

#define GPCMD_READ_TRACK_RZONE_INFO            0x52

#define GPCMD_READ_SUBCHANNEL                    0x42

#define GPCMD_READ_TOC_PMA_ATIP                    0x43

#define GPCMD_REPAIR_RZONE_TRACK            0x58

#define GPCMD_REPORT_KEY                    0xa4

#define GPCMD_REQUEST_SENSE                    0x03

#define GPCMD_RESERVE_RZONE_TRACK            0x53

#define GPCMD_SCAN                            0xba

#define GPCMD_SEEK                            0x2b

#define GPCMD_SEND_DVD_STRUCTURE            0xad

#define GPCMD_SEND_EVENT                    0xa2

#define GPCMD_SEND_KEY                            0xa3

#define GPCMD_SEND_OPC                            0x54

#define GPCMD_SET_READ_AHEAD                    0xa7

#define GPCMD_SET_STREAMING                    0xb6

#define GPCMD_START_STOP_UNIT                    0x1b

#define GPCMD_STOP_PLAY_SCAN                    0x4e

#define GPCMD_TEST_UNIT_READY                    0x00

#define GPCMD_VERIFY_10                            0x2f

#define GPCMD_WRITE_10                            0x2a

#define GPCMD_WRITE_AND_VERIFY_10            0x2e

/* This is listed as optional in ATAPI 2.6, but is (curiously)

 * missing from Mt. Fuji, Table 57.  It _is_ mentioned in Mt. Fuji

 * Table 377 as an MMC command for SCSi devices though...  Most ATAPI

 * drives support it. */

#define GPCMD_SET_SPEED                            0xbb

/* This seems to be a SCSI specific CD-ROM opcode

 * to play data at track/index */

#define GPCMD_PLAYAUDIO_TI                    0x48

/*

 * From MS Media Status Notification Support Specification. For

 * older drives only.

 */

#define GPCMD_GET_MEDIA_STATUS                    0xda

#define GPCMD_MODE_SENSE_6                    0x1a

/* Mode page codes for mode sense/set */

#define GPMODE_R_W_ERROR_PAGE                0x01

#define GPMODE_WRITE_PARMS_PAGE                0x05

#define GPMODE_AUDIO_CTL_PAGE                0x0e

#define GPMODE_POWER_PAGE                0x1a

#define GPMODE_FAULT_FAIL_PAGE                0x1c

#define GPMODE_TO_PROTECT_PAGE                0x1d

#define GPMODE_CAPABILITIES_PAGE        0x2a

#define GPMODE_ALL_PAGES                0x3f

/* Not in Mt. Fuji, but in ATAPI 2.6 -- depricated now in favor

 * of MODE_SENSE_POWER_PAGE */

#define GPMODE_CDROM_PAGE                0x0d

/*

 * Based on values from <linux/cdrom.h> but extending CD_MINS

 * to the maximum common size allowed by the Orange's Book ATIP

 *

 * 90 and 99 min CDs are also available but using them as the

 * upper limit reduces the effectiveness of the heuristic to

 * detect DVDs burned to less than 25% of their maximum capacity

 */

/* Some generally useful CD-ROM information */

#define CD_MINS                       80 /* max. minutes per CD */

#define CD_SECS                       60 /* seconds per minute */

#define CD_FRAMES                     75 /* frames per second */

#define CD_FRAMESIZE                2048 /* bytes per frame, "cooked" mode */

#define CD_MAX_BYTES       (CD_MINS * CD_SECS * CD_FRAMES * CD_FRAMESIZE)

#define CD_MAX_SECTORS     (CD_MAX_BYTES / 512)

/*

 * The MMC values are not IDE specific and might need to be moved

 * to a common header if they are also needed for the SCSI emulation

 */

/* Profile list from MMC-6 revision 1 table 91 */

#define MMC_PROFILE_NONE                0x0000

#define MMC_PROFILE_CD_ROM              0x0008

#define MMC_PROFILE_CD_R                0x0009

#define MMC_PROFILE_CD_RW               0x000A

#define MMC_PROFILE_DVD_ROM             0x0010

#define MMC_PROFILE_DVD_R_SR            0x0011

#define MMC_PROFILE_DVD_RAM             0x0012

#define MMC_PROFILE_DVD_RW_RO           0x0013

#define MMC_PROFILE_DVD_RW_SR           0x0014

#define MMC_PROFILE_DVD_R_DL_SR         0x0015

#define MMC_PROFILE_DVD_R_DL_JR         0x0016

#define MMC_PROFILE_DVD_RW_DL           0x0017

#define MMC_PROFILE_DVD_DDR             0x0018

#define MMC_PROFILE_DVD_PLUS_RW         0x001A

#define MMC_PROFILE_DVD_PLUS_R          0x001B

#define MMC_PROFILE_DVD_PLUS_RW_DL      0x002A

#define MMC_PROFILE_DVD_PLUS_R_DL       0x002B

#define MMC_PROFILE_BD_ROM              0x0040

#define MMC_PROFILE_BD_R_SRM            0x0041

#define MMC_PROFILE_BD_R_RRM            0x0042

#define MMC_PROFILE_BD_RE               0x0043

#define MMC_PROFILE_HDDVD_ROM           0x0050

#define MMC_PROFILE_HDDVD_R             0x0051

#define MMC_PROFILE_HDDVD_RAM           0x0052

#define MMC_PROFILE_HDDVD_RW            0x0053

#define MMC_PROFILE_HDDVD_R_DL          0x0058

#define MMC_PROFILE_HDDVD_RW_DL         0x005A

#define MMC_PROFILE_INVALID             0xFFFF

#define ATAPI_INT_REASON_CD             0x01 /* 0 = data transfer */

#define ATAPI_INT_REASON_IO             0x02 /* 1 = transfer to the host */

#define ATAPI_INT_REASON_REL            0x04

#define ATAPI_INT_REASON_TAG            0xf8

/* same constants as bochs */

#define ASC_ILLEGAL_OPCODE                   0x20

#define ASC_LOGICAL_BLOCK_OOR                0x21

#define ASC_INV_FIELD_IN_CMD_PACKET          0x24

#define ASC_INCOMPATIBLE_FORMAT              0x30

#define ASC_MEDIUM_NOT_PRESENT               0x3a

#define ASC_SAVING_PARAMETERS_NOT_SUPPORTED  0x39

#define CFA_NO_ERROR            0x00

#define CFA_MISC_ERROR          0x09

#define CFA_INVALID_COMMAND     0x20

#define CFA_INVALID_ADDRESS     0x21

#define CFA_ADDRESS_OVERFLOW    0x2f

#define SENSE_NONE            0

#define SENSE_NOT_READY       2

#define SENSE_ILLEGAL_REQUEST 5

#define SENSE_UNIT_ATTENTION  6

struct IDEState;

typedef void EndTransferFunc(struct IDEState *);

/* NOTE: IDEState represents in fact one drive */

typedef struct IDEState {

    /* ide config */

    int is_cdrom;

    int is_cf;

    int cylinders, heads, sectors;

    int64_t nb_sectors;

    int mult_sectors;

    int identify_set;

    uint16_t identify_data[256];

    qemu_irq irq;

    PCIDevice *pci_dev;

    struct BMDMAState *bmdma;

    int drive_serial;

    /* ide regs */

    uint8_t feature;

    uint8_t error;

    uint32_t nsector;

    uint8_t sector;

    uint8_t lcyl;

    uint8_t hcyl;

    /* other part of tf for lba48 support */

    uint8_t hob_feature;

    uint8_t hob_nsector;

    uint8_t hob_sector;

    uint8_t hob_lcyl;

    uint8_t hob_hcyl;

    uint8_t select;

    uint8_t status;

    /* 0x3f6 command, only meaningful for drive 0 */

    uint8_t cmd;

    /* set for lba48 access */

    uint8_t lba48;

    /* depends on bit 4 in select, only meaningful for drive 0 */

    struct IDEState *cur_drive;

    BlockDriverState *bs;

    /* ATAPI specific */

    uint8_t sense_key;

    uint8_t asc;

    int packet_transfer_size;

    int elementary_transfer_size;

    int io_buffer_index;

    int lba;

    int cd_sector_size;

    int atapi_dma; /* true if dma is requested for the packet cmd */

    /* ATA DMA state */

    int io_buffer_size;

    /* PIO transfer handling */

    int req_nb_sectors; /* number of sectors per interrupt */

    EndTransferFunc *end_transfer_func;

    uint8_t *data_ptr;

    uint8_t *data_end;

    uint8_t *io_buffer;

    QEMUTimer *sector_write_timer; /* only used for win2k install hack */

    uint32_t irq_count; /* counts IRQs when using win2k install hack */

    /* CF-ATA extended error */

    uint8_t ext_error;

    /* CF-ATA metadata storage */

    uint32_t mdata_size;

    uint8_t *mdata_storage;

    int media_changed;

} IDEState;

/* XXX: DVDs that could fit on a CD will be reported as a CD */

static inline int media_present(IDEState *s)

{

    return (s->nb_sectors > 0);

}

static inline int media_is_dvd(IDEState *s)

{

    return (media_present(s) && s->nb_sectors > CD_MAX_SECTORS);

}

static inline int media_is_cd(IDEState *s)

{

    return (media_present(s) && s->nb_sectors <= CD_MAX_SECTORS);

}

#define BM_STATUS_DMAING 0x01

#define BM_STATUS_ERROR  0x02

#define BM_STATUS_INT    0x04

#define BM_CMD_START     0x01

#define BM_CMD_READ      0x08

#define IDE_TYPE_PIIX3   0

#define IDE_TYPE_CMD646  1

#define IDE_TYPE_PIIX4   2

/* CMD646 specific */

#define MRDMODE                0x71

#define   MRDMODE_INTR_CH0        0x04

#define   MRDMODE_INTR_CH1        0x08

#define   MRDMODE_BLK_CH0        0x10

#define   MRDMODE_BLK_CH1        0x20

#define UDIDETCR0        0x73

#define UDIDETCR1        0x7B

typedef struct BMDMAState {

    uint8_t cmd;

    uint8_t status;

    uint32_t addr;

    struct PCIIDEState *pci_dev;

    /* current transfer state */

    uint32_t cur_addr;

    uint32_t cur_prd_last;

    uint32_t cur_prd_addr;

    uint32_t cur_prd_len;

    IDEState *ide_if;

    BlockDriverCompletionFunc *dma_cb;

    BlockDriverAIOCB *aiocb;

} BMDMAState;

typedef struct PCIIDEState {

    PCIDevice dev;

    IDEState ide_if[4];

    BMDMAState bmdma[2];

    int type; /* see IDE_TYPE_xxx */

} PCIIDEState;

static void ide_dma_start(IDEState *s, BlockDriverCompletionFunc *dma_cb);

static void ide_atapi_cmd_read_dma_cb(void *opaque, int ret);

static void padstr(char *str, const char *src, int len)

{

    int i, v;

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

        if (*src)

            v = *src++;

        else

            v = ' ';

        str[i^1] = v;

    }

}

static void padstr8(uint8_t *buf, int buf_size, const char *src)

{

    int i;

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

        if (*src)

            buf[i] = *src++;

        else

            buf[i] = ' ';

    }

}

static void put_le16(uint16_t *p, unsigned int v)

{

    *p = cpu_to_le16(v);

}

static void ide_identify(IDEState *s)

{

    uint16_t *p;

    unsigned int oldsize;

    char buf[20];

    if (s->identify_set) {

        memcpy(s->io_buffer, s->identify_data, sizeof(s->identify_data));

        return;

    }

    memset(s->io_buffer, 0, 512);

    p = (uint16_t *)s->io_buffer;

    put_le16(p + 0, 0x0040);

    put_le16(p + 1, s->cylinders);

    put_le16(p + 3, s->heads);

    put_le16(p + 4, 512 * s->sectors); /* XXX: retired, remove ? */

    put_le16(p + 5, 512); /* XXX: retired, remove ? */

    put_le16(p + 6, s->sectors);

    snprintf(buf, sizeof(buf), "QM%05d", s->drive_serial);

    padstr((char *)(p + 10), buf, 20); /* serial number */

    put_le16(p + 20, 3); /* XXX: retired, remove ? */

    put_le16(p + 21, 512); /* cache size in sectors */

    put_le16(p + 22, 4); /* ecc bytes */

    padstr((char *)(p + 23), QEMU_VERSION, 8); /* firmware version */

    padstr((char *)(p + 27), "QEMU HARDDISK", 40); /* model */

#if MAX_MULT_SECTORS > 1

    put_le16(p + 47, 0x8000 | MAX_MULT_SECTORS);

#endif

    put_le16(p + 48, 1); /* dword I/O */

    put_le16(p + 49, (1 << 11) | (1 << 9) | (1 << 8)); /* DMA and LBA supported */

    put_le16(p + 51, 0x200); /* PIO transfer cycle */

    put_le16(p + 52, 0x200); /* DMA transfer cycle */

    put_le16(p + 53, 1 | (1 << 1) | (1 << 2)); /* words 54-58,64-70,88 are valid */

    put_le16(p + 54, s->cylinders);

    put_le16(p + 55, s->heads);

    put_le16(p + 56, s->sectors);

    oldsize = s->cylinders * s->heads * s->sectors;

    put_le16(p + 57, oldsize);

    put_le16(p + 58, oldsize >> 16);

    if (s->mult_sectors)

        put_le16(p + 59, 0x100 | s->mult_sectors);

    put_le16(p + 60, s->nb_sectors);

    put_le16(p + 61, s->nb_sectors >> 16);

    put_le16(p + 62, 0x07); /* single word dma0-2 supported */

    put_le16(p + 63, 0x07); /* mdma0-2 supported */

    put_le16(p + 65, 120);

    put_le16(p + 66, 120);

    put_le16(p + 67, 120);

    put_le16(p + 68, 120);

    put_le16(p + 80, 0xf0); /* ata3 -> ata6 supported */

    put_le16(p + 81, 0x16); /* conforms to ata5 */

    put_le16(p + 82, (1 << 14));

    /* 13=flush_cache_ext,12=flush_cache,10=lba48 */

    put_le16(p + 83, (1 << 14) | (1 << 13) | (1 <<12) | (1 << 10));

    put_le16(p + 84, (1 << 14));

    put_le16(p + 85, (1 << 14));

    /* 13=flush_cache_ext,12=flush_cache,10=lba48 */

    put_le16(p + 86, (1 << 14) | (1 << 13) | (1 <<12) | (1 << 10));

    put_le16(p + 87, (1 << 14));

    put_le16(p + 88, 0x3f | (1 << 13)); /* udma5 set and supported */

    put_le16(p + 93, 1 | (1 << 14) | 0x2000);

    put_le16(p + 100, s->nb_sectors);

    put_le16(p + 101, s->nb_sectors >> 16);

    put_le16(p + 102, s->nb_sectors >> 32);

    put_le16(p + 103, s->nb_sectors >> 48);

    memcpy(s->identify_data, p, sizeof(s->identify_data));

    s->identify_set = 1;

}

static void ide_atapi_identify(IDEState *s)

{

    uint16_t *p;

    char buf[20];

    if (s->identify_set) {

        memcpy(s->io_buffer, s->identify_data, sizeof(s->identify_data));

        return;

    }

    memset(s->io_buffer, 0, 512);

    p = (uint16_t *)s->io_buffer;

    /* Removable CDROM, 50us response, 12 byte packets */

    put_le16(p + 0, (2 << 14) | (5 << 8) | (1 << 7) | (2 << 5) | (0 << 0));

    snprintf(buf, sizeof(buf), "QM%05d", s->drive_serial);

    padstr((char *)(p + 10), buf, 20); /* serial number */

    put_le16(p + 20, 3); /* buffer type */

    put_le16(p + 21, 512); /* cache size in sectors */

    put_le16(p + 22, 4); /* ecc bytes */

    padstr((char *)(p + 23), QEMU_VERSION, 8); /* firmware version */

    padstr((char *)(p + 27), "QEMU DVD-ROM", 40); /* model */

    put_le16(p + 48, 1); /* dword I/O (XXX: should not be set on CDROM) */

#ifdef USE_DMA_CDROM

    put_le16(p + 49, 1 << 9 | 1 << 8); /* DMA and LBA supported */

    put_le16(p + 53, 7); /* words 64-70, 54-58, 88 valid */

    put_le16(p + 62, 7);  /* single word dma0-2 supported */

    put_le16(p + 63, 7);  /* mdma0-2 supported */

    put_le16(p + 64, 0x3f); /* PIO modes supported */

#else

    put_le16(p + 49, 1 << 9); /* LBA supported, no DMA */

    put_le16(p + 53, 3); /* words 64-70, 54-58 valid */

    put_le16(p + 63, 0x103); /* DMA modes XXX: may be incorrect */

    put_le16(p + 64, 1); /* PIO modes */

#endif

    put_le16(p + 65, 0xb4); /* minimum DMA multiword tx cycle time */

    put_le16(p + 66, 0xb4); /* recommended DMA multiword tx cycle time */

    put_le16(p + 67, 0x12c); /* minimum PIO cycle time without flow control */

    put_le16(p + 68, 0xb4); /* minimum PIO cycle time with IORDY flow control */

    put_le16(p + 71, 30); /* in ns */

    put_le16(p + 72, 30); /* in ns */

    put_le16(p + 80, 0x1e); /* support up to ATA/ATAPI-4 */

#ifdef USE_DMA_CDROM

    put_le16(p + 88, 0x3f | (1 << 13)); /* udma5 set and supported */

#endif

    memcpy(s->identify_data, p, sizeof(s->identify_data));

    s->identify_set = 1;

}

static void ide_cfata_identify(IDEState *s)

{

    uint16_t *p;

    uint32_t cur_sec;

    char buf[20];

    p = (uint16_t *) s->identify_data;

    if (s->identify_set)

        goto fill_buffer;

    memset(p, 0, sizeof(s->identify_data));

    cur_sec = s->cylinders * s->heads * s->sectors;

    put_le16(p + 0, 0x848a);                        /* CF Storage Card signature */

    put_le16(p + 1, s->cylinders);                /* Default cylinders */

    put_le16(p + 3, s->heads);                        /* Default heads */

    put_le16(p + 6, s->sectors);                /* Default sectors per track */

    put_le16(p + 7, s->nb_sectors >> 16);        /* Sectors per card */

    put_le16(p + 8, s->nb_sectors);                /* Sectors per card */

    snprintf(buf, sizeof(buf), "QM%05d", s->drive_serial);

    padstr((char *)(p + 10), buf, 20);        /* Serial number in ASCII */

    put_le16(p + 22, 0x0004);                        /* ECC bytes */

    padstr((char *) (p + 23), QEMU_VERSION, 8);        /* Firmware Revision */

    padstr((char *) (p + 27), "QEMU MICRODRIVE", 40);/* Model number */

#if MAX_MULT_SECTORS > 1

    put_le16(p + 47, 0x8000 | MAX_MULT_SECTORS);

#else

    put_le16(p + 47, 0x0000);

#endif

    put_le16(p + 49, 0x0f00);                        /* Capabilities */

    put_le16(p + 51, 0x0002);                        /* PIO cycle timing mode */

    put_le16(p + 52, 0x0001);                        /* DMA cycle timing mode */

    put_le16(p + 53, 0x0003);                        /* Translation params valid */

    put_le16(p + 54, s->cylinders);                /* Current cylinders */

    put_le16(p + 55, s->heads);                        /* Current heads */

    put_le16(p + 56, s->sectors);                /* Current sectors */

    put_le16(p + 57, cur_sec);                        /* Current capacity */

    put_le16(p + 58, cur_sec >> 16);                /* Current capacity */

    if (s->mult_sectors)                        /* Multiple sector setting */

        put_le16(p + 59, 0x100 | s->mult_sectors);

    put_le16(p + 60, s->nb_sectors);                /* Total LBA sectors */

    put_le16(p + 61, s->nb_sectors >> 16);        /* Total LBA sectors */

    put_le16(p + 63, 0x0203);                        /* Multiword DMA capability */

    put_le16(p + 64, 0x0001);                        /* Flow Control PIO support */

    put_le16(p + 65, 0x0096);                        /* Min. Multiword DMA cycle */

    put_le16(p + 66, 0x0096);                        /* Rec. Multiword DMA cycle */

    put_le16(p + 68, 0x00b4);                        /* Min. PIO cycle time */

    put_le16(p + 82, 0x400c);                        /* Command Set supported */

    put_le16(p + 83, 0x7068);                        /* Command Set supported */

    put_le16(p + 84, 0x4000);                        /* Features supported */

    put_le16(p + 85, 0x000c);                        /* Command Set enabled */

    put_le16(p + 86, 0x7044);                        /* Command Set enabled */

    put_le16(p + 87, 0x4000);                        /* Features enabled */

    put_le16(p + 91, 0x4060);                        /* Current APM level */

    put_le16(p + 129, 0x0002);                        /* Current features option */

    put_le16(p + 130, 0x0005);                        /* Reassigned sectors */

    put_le16(p + 131, 0x0001);                        /* Initial power mode */

    put_le16(p + 132, 0x0000);                        /* User signature */

    put_le16(p + 160, 0x8100);                        /* Power requirement */

    put_le16(p + 161, 0x8001);                        /* CF command set */

    s->identify_set = 1;

fill_buffer:

    memcpy(s->io_buffer, p, sizeof(s->identify_data));

}

static void ide_set_signature(IDEState *s)

{

    s->select &= 0xf0; /* clear head */

    /* put signature */

    s->nsector = 1;

    s->sector = 1;

    if (s->is_cdrom) {

        s->lcyl = 0x14;

        s->hcyl = 0xeb;

    } else if (s->bs) {

        s->lcyl = 0;

        s->hcyl = 0;

    } else {

        s->lcyl = 0xff;

        s->hcyl = 0xff;

    }

}

static inline void ide_abort_command(IDEState *s)

{

    s->status = READY_STAT | ERR_STAT;

    s->error = ABRT_ERR;

}

static inline void ide_set_irq(IDEState *s)

{

    BMDMAState *bm = s->bmdma;

    if (!(s->cmd & IDE_CMD_DISABLE_IRQ)) {

        if (bm) {

            bm->status |= BM_STATUS_INT;

        }

        qemu_irq_raise(s->irq);

    }

}

/* prepare data transfer and tell what to do after */

static void ide_transfer_start(IDEState *s, uint8_t *buf, int size,

                               EndTransferFunc *end_transfer_func)

{

    s->end_transfer_func = end_transfer_func;

    s->data_ptr = buf;

    s->data_end = buf + size;

    if (!(s->status & ERR_STAT))

        s->status |= DRQ_STAT;

}

static void ide_transfer_stop(IDEState *s)

{

    s->end_transfer_func = ide_transfer_stop;

    s->data_ptr = s->io_buffer;

    s->data_end = s->io_buffer;

    s->status &= ~DRQ_STAT;

}

static int64_t ide_get_sector(IDEState *s)

{

    int64_t sector_num;

    if (s->select & 0x40) {

        /* lba */

        if (!s->lba48) {

            sector_num = ((s->select & 0x0f) << 24) | (s->hcyl << 16) |

                (s->lcyl << 8) | s->sector;

        } else {

            sector_num = ((int64_t)s->hob_hcyl << 40) |

                ((int64_t) s->hob_lcyl << 32) |

                ((int64_t) s->hob_sector << 24) |

                ((int64_t) s->hcyl << 16) |

                ((int64_t) s->lcyl << 8) | s->sector;

        }

    } else {

        sector_num = ((s->hcyl << 8) | s->lcyl) * s->heads * s->sectors +

            (s->select & 0x0f) * s->sectors + (s->sector - 1);

    }

    return sector_num;

}

static void ide_set_sector(IDEState *s, int64_t sector_num)

{

    unsigned int cyl, r;

    if (s->select & 0x40) {

        if (!s->lba48) {

            s->select = (s->select & 0xf0) | (sector_num >> 24);

            s->hcyl = (sector_num >> 16);

            s->lcyl = (sector_num >> 8);

            s->sector = (sector_num);

        } else {

            s->sector = sector_num;

            s->lcyl = sector_num >> 8;

            s->hcyl = sector_num >> 16;

            s->hob_sector = sector_num >> 24;

            s->hob_lcyl = sector_num >> 32;

            s->hob_hcyl = sector_num >> 40;

        }

    } else {

        cyl = sector_num / (s->heads * s->sectors);

        r = sector_num % (s->heads * s->sectors);

        s->hcyl = cyl >> 8;

        s->lcyl = cyl;

        s->select = (s->select & 0xf0) | ((r / s->sectors) & 0x0f);

        s->sector = (r % s->sectors) + 1;

    }

}

static void ide_sector_read(IDEState *s)

{

    int64_t sector_num;

    int ret, n;

    s->status = READY_STAT | SEEK_STAT;

    s->error = 0; /* not needed by IDE spec, but needed by Windows */

    sector_num = ide_get_sector(s);

    n = s->nsector;

    if (n == 0) {

        /* no more sector to read from disk */

        ide_transfer_stop(s);

    } else {

#if defined(DEBUG_IDE)

        printf("read sector=%Ld\n", sector_num);

#endif

        if (n > s->req_nb_sectors)

            n = s->req_nb_sectors;

        ret = bdrv_read(s->bs, sector_num, s->io_buffer, n);

        ide_transfer_start(s, s->io_buffer, 512 * n, ide_sector_read);

        ide_set_irq(s);

        ide_set_sector(s, sector_num + n);

        s->nsector -= n;

    }

}

/* return 0 if buffer completed */

static int dma_buf_rw(BMDMAState *bm, int is_write)

{

    IDEState *s = bm->ide_if;

    struct {

        uint32_t addr;

        uint32_t size;

    } prd;

    int l, len;

    for(;;) {

        l = s->io_buffer_size - s->io_buffer_index;

        if (l <= 0)

            break;

        if (bm->cur_prd_len == 0) {

            /* end of table (with a fail safe of one page) */

            if (bm->cur_prd_last ||

                (bm->cur_addr - bm->addr) >= 4096)

                return 0;

            cpu_physical_memory_read(bm->cur_addr, (uint8_t *)&prd, 8);

            bm->cur_addr += 8;

            prd.addr = le32_to_cpu(prd.addr);

            prd.size = le32_to_cpu(prd.size);

            len = prd.size & 0xfffe;

            if (len == 0)

                len = 0x10000;

            bm->cur_prd_len = len;

            bm->cur_prd_addr = prd.addr;

            bm->cur_prd_last = (prd.size & 0x80000000);

        }

        if (l > bm->cur_prd_len)

            l = bm->cur_prd_len;

        if (l > 0) {

            if (is_write) {

                cpu_physical_memory_write(bm->cur_prd_addr,

                                          s->io_buffer + s->io_buffer_index, l);

            } else {

                cpu_physical_memory_read(bm->cur_prd_addr,

                                          s->io_buffer + s->io_buffer_index, l);

            }

            bm->cur_prd_addr += l;

            bm->cur_prd_len -= l;

            s->io_buffer_index += l;

        }

    }

    return 1;

}

/* XXX: handle errors */

static void ide_read_dma_cb(void *opaque, int ret)

{

    BMDMAState *bm = opaque;

    IDEState *s = bm->ide_if;

    int n;

    int64_t sector_num;

    n = s->io_buffer_size >> 9;

    sector_num = ide_get_sector(s);

    if (n > 0) {

        sector_num += n;

        ide_set_sector(s, sector_num);

        s->nsector -= n;

        if (dma_buf_rw(bm, 1) == 0)

            goto eot;

    }

    /* end of transfer ? */

    if (s->nsector == 0) {

        s->status = READY_STAT | SEEK_STAT;

        ide_set_irq(s);

    eot:

        bm->status &= ~BM_STATUS_DMAING;

        bm->status |= BM_STATUS_INT;

        bm->dma_cb = NULL;

        bm->ide_if = NULL;

        bm->aiocb = NULL;

        return;

    }

    /* launch next transfer */

    n = s->nsector;

    if (n > IDE_DMA_BUF_SECTORS)

        n = IDE_DMA_BUF_SECTORS;

    s->io_buffer_index = 0;

    s->io_buffer_size = n * 512;

#ifdef DEBUG_AIO

    printf("aio_read: sector_num=%lld n=%d\n", sector_num, n);

#endif

    bm->aiocb = bdrv_aio_read(s->bs, sector_num, s->io_buffer, n,

                              ide_read_dma_cb, bm);

}

static void ide_sector_read_dma(IDEState *s)

{

    s->status = READY_STAT | SEEK_STAT | DRQ_STAT | BUSY_STAT;

    s->io_buffer_index = 0;

    s->io_buffer_size = 0;

    ide_dma_start(s, ide_read_dma_cb);

}

static void ide_sector_write_timer_cb(void *opaque)

{

    IDEState *s = opaque;

    ide_set_irq(s);

}

static void ide_sector_write(IDEState *s)

{

    int64_t sector_num;

    int ret, n, n1;

    s->status = READY_STAT | SEEK_STAT;

    sector_num = ide_get_sector(s);

#if defined(DEBUG_IDE)

    printf("write sector=%Ld\n", sector_num);

#endif

    n = s->nsector;

    if (n > s->req_nb_sectors)

        n = s->req_nb_sectors;

    ret = bdrv_write(s->bs, sector_num, s->io_buffer, n);

    s->nsector -= n;

    if (s->nsector == 0) {

        /* no more sectors to write */

        ide_transfer_stop(s);

    } else {

        n1 = s->nsector;

        if (n1 > s->req_nb_sectors)

            n1 = s->req_nb_sectors;

        ide_transfer_start(s, s->io_buffer, 512 * n1, ide_sector_write);

    }

    ide_set_sector(s, sector_num + n);

#ifdef TARGET_I386

    if (win2k_install_hack && ((++s->irq_count % 16) == 0)) {

        /* It seems there is a bug in the Windows 2000 installer HDD

           IDE driver which fills the disk with empty logs when the

           IDE write IRQ comes too early. This hack tries to correct

           that at the expense of slower write performances. Use this

           option _only_ to install Windows 2000. You must disable it

           for normal use. */

        qemu_mod_timer(s->sector_write_timer, 

                       qemu_get_clock(vm_clock) + (ticks_per_sec / 1000));

    } else 

#endif

    {

        ide_set_irq(s);

    }

}

/* XXX: handle errors */

static void ide_write_dma_cb(void *opaque, int ret)

{

    BMDMAState *bm = opaque;

    IDEState *s = bm->ide_if;

    int n;

    int64_t sector_num;

    n = s->io_buffer_size >> 9;

    sector_num = ide_get_sector(s);

    if (n > 0) {

        sector_num += n;

        ide_set_sector(s, sector_num);

        s->nsector -= n;

    }

    /* end of transfer ? */

    if (s->nsector == 0) {

        s->status = READY_STAT | SEEK_STAT;

        ide_set_irq(s);

    eot:

        bm->status &= ~BM_STATUS_DMAING;

        bm->status |= BM_STATUS_INT;

        bm->dma_cb = NULL;

        bm->ide_if = NULL;

        bm->aiocb = NULL;

        return;

    }

    /* launch next transfer */

    n = s->nsector;

    if (n > IDE_DMA_BUF_SECTORS)

        n = IDE_DMA_BUF_SECTORS;

    s->io_buffer_index = 0;

    s->io_buffer_size = n * 512;

    if (dma_buf_rw(bm, 0) == 0)

        goto eot;

#ifdef DEBUG_AIO

    printf("aio_write: sector_num=%lld n=%d\n", sector_num, n);

#endif

    bm->aiocb = bdrv_aio_write(s->bs, sector_num, s->io_buffer, n,

                               ide_write_dma_cb, bm);

}

static void ide_sector_write_dma(IDEState *s)

{

    s->status = READY_STAT | SEEK_STAT | DRQ_STAT | BUSY_STAT;

    s->io_buffer_index = 0;

    s->io_buffer_size = 0;

    ide_dma_start(s, ide_write_dma_cb);

}

static void ide_atapi_cmd_ok(IDEState *s)

{

    s->error = 0;

    s->status = READY_STAT | SEEK_STAT;

    s->nsector = (s->nsector & ~7) | ATAPI_INT_REASON_IO | ATAPI_INT_REASON_CD;

    ide_set_irq(s);

}

static void ide_atapi_cmd_error(IDEState *s, int sense_key, int asc)

{

#ifdef DEBUG_IDE_ATAPI

    printf("atapi_cmd_error: sense=0x%x asc=0x%x\n", sense_key, asc);

#endif

    s->error = sense_key << 4;

    s->status = READY_STAT | ERR_STAT;

    s->nsector = (s->nsector & ~7) | ATAPI_INT_REASON_IO | ATAPI_INT_REASON_CD;

    s->sense_key = sense_key;

    s->asc = asc;

    ide_set_irq(s);

}

static inline void cpu_to_ube16(uint8_t *buf, int val)

{

    buf[0] = val >> 8;

    buf[1] = val;

}

static inline void cpu_to_ube32(uint8_t *buf, unsigned int val)

{

    buf[0] = val >> 24;

    buf[1] = val >> 16;

    buf[2] = val >> 8;

    buf[3] = val;

}

static inline int ube16_to_cpu(const uint8_t *buf)

{

    return (buf[0] << 8) | buf[1];

}

static inline int ube32_to_cpu(const uint8_t *buf)

{

    return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];

}

static void lba_to_msf(uint8_t *buf, int lba)

{

    lba += 150;

    buf[0] = (lba / 75) / 60;

    buf[1] = (lba / 75) % 60;

    buf[2] = lba % 75;

}

static void cd_data_to_raw(uint8_t *buf, int lba)

{

    /* sync bytes */

    buf[0] = 0x00;

    memset(buf + 1, 0xff, 10);

    buf[11] = 0x00;

    buf += 12;

    /* MSF */

    lba_to_msf(buf, lba);

    buf[3] = 0x01; /* mode 1 data */

    buf += 4;

    /* data */

    buf += 2048;

    /* XXX: ECC not computed */

    memset(buf, 0, 288);

}

static int cd_read_sector(BlockDriverState *bs, int lba, uint8_t *buf,

                           int sector_size)

{

    int ret;

    switch(sector_size) {

    case 2048:

        ret = bdrv_read(bs, (int64_t)lba << 2, buf, 4);

        break;

    case 2352:

        ret = bdrv_read(bs, (int64_t)lba << 2, buf + 16, 4);

        if (ret < 0)

            return ret;

        cd_data_to_raw(buf, lba);

        break;

    default:

        ret = -EIO;

        break;

    }

    return ret;

}

static void ide_atapi_io_error(IDEState *s, int ret)

{

    /* XXX: handle more errors */

    if (ret == -ENOMEDIUM) {

        ide_atapi_cmd_error(s, SENSE_NOT_READY,

                            ASC_MEDIUM_NOT_PRESENT);

    } else {

        ide_atapi_cmd_error(s, SENSE_ILLEGAL_REQUEST,

                            ASC_LOGICAL_BLOCK_OOR);

    }

}

/* The whole ATAPI transfer logic is handled in this function */

static void ide_atapi_cmd_reply_end(IDEState *s)

{

    int byte_count_limit, size, ret;

#ifdef DEBUG_IDE_ATAPI

    printf("reply: tx_size=%d elem_tx_size=%d index=%d\n",

           s->packet_transfer_size,

           s->elementary_transfer_size,

           s->io_buffer_index);

#endif

    if (s->packet_transfer_size <= 0) {

        /* end of transfer */

        ide_transfer_stop(s);

        s->status = READY_STAT | SEEK_STAT;

        s->nsector = (s->nsector & ~7) | ATAPI_INT_REASON_IO | ATAPI_INT_REASON_CD;

        ide_set_irq(s);

#ifdef DEBUG_IDE_ATAPI

        printf("status=0x%x\n", s->status);

#endif

    } else {

        /* see if a new sector must be read */

        if (s->lba != -1 && s->io_buffer_index >= s->cd_sector_size) {

            ret = cd_read_sector(s->bs, s->lba, s->io_buffer, s->cd_sector_size);

            if (ret < 0) {

                ide_transfer_stop(s);

                ide_atapi_io_error(s, ret);

                return;

            }

            s->lba++;

            s->io_buffer_index = 0;

        }

        if (s->elementary_transfer_size > 0) {

            /* there are some data left to transmit in this elementary

               transfer */

            size = s->cd_sector_size - s->io_buffer_index;

            if (size > s->elementary_transfer_size)

                size = s->elementary_transfer_size;

            ide_transfer_start(s, s->io_buffer + s->io_buffer_index,

                               size, ide_atapi_cmd_reply_end);

            s->packet_transfer_size -= size;

            s->elementary_transfer_size -= size;

            s->io_buffer_index += size;

        } else {

            /* a new transfer is needed */

            s->nsector = (s->nsector & ~7) | ATAPI_INT_REASON_IO;

            byte_count_limit = s->lcyl | (s->hcyl << 8);

#ifdef DEBUG_IDE_ATAPI

            printf("byte_count_limit=%d\n", byte_count_limit);

#endif

            if (byte_count_limit == 0xffff)

                byte_count_limit--;

            size = s->packet_transfer_size;

            if (size > byte_count_limit) {

                /* byte count limit must be even if this case */

                if (byte_count_limit & 1)

                    byte_count_limit--;

                size = byte_count_limit;

            }

            s->lcyl = size;

            s->hcyl = size >> 8;

            s->elementary_transfer_size = size;

            /* we cannot transmit more than one sector at a time */

            if (s->lba != -1) {

                if (size > (s->cd_sector_size - s->io_buffer_index))

                    size = (s->cd_sector_size - s->io_buffer_index);

            }

            ide_transfer_start(s, s->io_buffer + s->io_buffer_index,

                               size, ide_atapi_cmd_reply_end);

            s->packet_transfer_size -= size;

            s->elementary_transfer_size -= size;

            s->io_buffer_index += size;

            ide_set_irq(s);

#ifdef DEBUG_IDE_ATAPI

            printf("status=0x%x\n", s->status);

#endif

        }

    }

}

/* send a reply of 'size' bytes in s->io_buffer to an ATAPI command */

static void ide_atapi_cmd_reply(IDEState *s, int size, int max_size)

{

    if (size > max_size)

        size = max_size;

    s->lba = -1; /* no sector read */

    s->packet_transfer_size = size;

    s->io_buffer_size = size;    /* dma: send the reply data as one chunk */

    s->elementary_transfer_size = 0;

    s->io_buffer_index = 0;

    if (s->atapi_dma) {

            s->status = READY_STAT | SEEK_STAT | DRQ_STAT;

        ide_dma_start(s, ide_atapi_cmd_read_dma_cb);

    } else {

            s->status = READY_STAT | SEEK_STAT;

            ide_atapi_cmd_reply_end(s);

    }

}

/* start a CD-CDROM read command */

static void ide_atapi_cmd_read_pio(IDEState *s, int lba, int nb_sectors,

                                   int sector_size)

{

    s->lba = lba;

    s->packet_transfer_size = nb_sectors * sector_size;