src/block.c

// Disk setup and access
//
// Copyright (C) 2008,2009  Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2002  MandrakeSoft S.A.
//
// This file may be distributed under the terms of the GNU LGPLv3 license.

#include "disk.h" // struct ata_s
#include "biosvar.h" // GET_GLOBAL
#include "cmos.h" // inb_cmos
#include "util.h" // dprintf
#include "ata.h" // process_ata_op

struct drives_s Drives VAR16VISIBLE;


/****************************************************************
 * Disk geometry translation
 ****************************************************************/

static u8
get_translation(int driveid)
{
    u8 type = GET_GLOBAL(Drives.drives[driveid].type);
    if (! CONFIG_COREBOOT && type == DTYPE_ATA) {
        // Emulators pass in the translation info via nvram.
        u8 ataid = GET_GLOBAL(Drives.drives[driveid].cntl_id);
        u8 channel = ataid / 2;
        u8 translation = inb_cmos(CMOS_BIOS_DISKTRANSFLAG + channel/2);
        translation >>= 2 * (ataid % 4);
        translation &= 0x03;
        return translation;
    }

    // On COREBOOT, use a heuristic to determine translation type.
    u16 heads = GET_GLOBAL(Drives.drives[driveid].pchs.heads);
    u16 cylinders = GET_GLOBAL(Drives.drives[driveid].pchs.cylinders);
    u16 spt = GET_GLOBAL(Drives.drives[driveid].pchs.spt);

    if (cylinders <= 1024 && heads <= 16 && spt <= 63)
        return TRANSLATION_NONE;
    if (cylinders * heads <= 131072)
        return TRANSLATION_LARGE;
    return TRANSLATION_LBA;
}

void
setup_translation(int driveid)
{
    u8 translation = get_translation(driveid);
    SET_GLOBAL(Drives.drives[driveid].translation, translation);

    u8 ataid = GET_GLOBAL(Drives.drives[driveid].cntl_id);
    u8 channel = ataid / 2;
    u8 slave = ataid % 2;
    u16 heads = GET_GLOBAL(Drives.drives[driveid].pchs.heads);
    u16 cylinders = GET_GLOBAL(Drives.drives[driveid].pchs.cylinders);
    u16 spt = GET_GLOBAL(Drives.drives[driveid].pchs.spt);
    u64 sectors = GET_GLOBAL(Drives.drives[driveid].sectors);

    dprintf(1, "ata%d-%d: PCHS=%u/%d/%d translation="
            , channel, slave, cylinders, heads, spt);
    switch (translation) {
    case TRANSLATION_NONE:
        dprintf(1, "none");
        break;
    case TRANSLATION_LBA:
        dprintf(1, "lba");
        spt = 63;
        if (sectors > 63*255*1024) {
            heads = 255;
            cylinders = 1024;
            break;
        }
        u32 sect = (u32)sectors / 63;
        heads = sect / 1024;
        if (heads>128)
            heads = 255;
        else if (heads>64)
            heads = 128;
        else if (heads>32)
            heads = 64;
        else if (heads>16)
            heads = 32;
        else
            heads = 16;
        cylinders = sect / heads;
        break;
    case TRANSLATION_RECHS:
        dprintf(1, "r-echs");
        // Take care not to overflow
        if (heads==16) {
            if (cylinders>61439)
                cylinders=61439;
            heads=15;
            cylinders = (u16)((u32)(cylinders)*16/15);
        }
        // then go through the large bitshift process
    case TRANSLATION_LARGE:
        if (translation == TRANSLATION_LARGE)
            dprintf(1, "large");
        while (cylinders > 1024) {
            cylinders >>= 1;
            heads <<= 1;

            // If we max out the head count
            if (heads > 127)
                break;
        }
        break;
    }
    // clip to 1024 cylinders in lchs
    if (cylinders > 1024)
        cylinders = 1024;
    dprintf(1, " LCHS=%d/%d/%d\n", cylinders, heads, spt);

    SET_GLOBAL(Drives.drives[driveid].lchs.heads, heads);
    SET_GLOBAL(Drives.drives[driveid].lchs.cylinders, cylinders);
    SET_GLOBAL(Drives.drives[driveid].lchs.spt, spt);
}


/****************************************************************
 * Drive mapping
 ****************************************************************/

// Fill in Fixed Disk Parameter Table (located in ebda).
static void
fill_fdpt(int driveid)
{
    if (driveid > 1)
        return;

    u16 nlc   = GET_GLOBAL(Drives.drives[driveid].lchs.cylinders);
    u16 nlh   = GET_GLOBAL(Drives.drives[driveid].lchs.heads);
    u16 nlspt = GET_GLOBAL(Drives.drives[driveid].lchs.spt);

    u16 npc   = GET_GLOBAL(Drives.drives[driveid].pchs.cylinders);
    u16 nph   = GET_GLOBAL(Drives.drives[driveid].pchs.heads);
    u16 npspt = GET_GLOBAL(Drives.drives[driveid].pchs.spt);

    struct fdpt_s *fdpt = &get_ebda_ptr()->fdpt[driveid];
    fdpt->precompensation = 0xffff;
    fdpt->drive_control_byte = 0xc0 | ((nph > 8) << 3);
    fdpt->landing_zone = npc;
    fdpt->cylinders = nlc;
    fdpt->heads = nlh;
    fdpt->sectors = nlspt;

    if (nlc == npc && nlh == nph && nlspt == npspt)
        // no logical CHS mapping used, just physical CHS
        // use Standard Fixed Disk Parameter Table (FDPT)
        return;

    // complies with Phoenix style Translated Fixed Disk Parameter
    // Table (FDPT)
    fdpt->phys_cylinders = npc;
    fdpt->phys_heads = nph;
    fdpt->phys_sectors = npspt;
    fdpt->a0h_signature = 0xa0;

    // Checksum structure.
    fdpt->checksum -= checksum(fdpt, sizeof(*fdpt));

    if (driveid == 0)
        SET_IVT(0x41, SEGOFF(get_ebda_seg(), offsetof(
                                 struct extended_bios_data_area_s, fdpt[0])));
    else
        SET_IVT(0x46, SEGOFF(get_ebda_seg(), offsetof(
                                 struct extended_bios_data_area_s, fdpt[1])));
}

// Map a drive (that was registered via add_bcv_hd)
void
map_hd_drive(int driveid)
{
    // fill hdidmap
    u8 hdcount = GET_BDA(hdcount);
    if (hdcount >= ARRAY_SIZE(Drives.idmap[0]))
        return;
    dprintf(3, "Mapping hd driveid %d to %d\n", driveid, hdcount);
    SET_GLOBAL(Drives.idmap[EXTTYPE_HD][hdcount], driveid);
    SET_BDA(hdcount, hdcount + 1);

    // Fill "fdpt" structure.
    fill_fdpt(hdcount);
}

// Map a cd
void
map_cd_drive(int driveid)
{
    // fill cdidmap
    u8 cdcount = GET_GLOBAL(Drives.cdcount);
    if (cdcount >= ARRAY_SIZE(Drives.idmap[0]))
        return;
    dprintf(3, "Mapping cd driveid %d to %d\n", driveid, cdcount);
    SET_GLOBAL(Drives.idmap[EXTTYPE_CD][cdcount], driveid);
    SET_GLOBAL(Drives.cdcount, cdcount+1);
}

// Map a floppy
void
map_floppy_drive(int driveid)
{
    // fill idmap
    u8 floppycount = GET_GLOBAL(Drives.floppycount);
    if (floppycount >= ARRAY_SIZE(Drives.idmap[0]))
        return;
    dprintf(3, "Mapping floppy driveid %d to %d\n", driveid, floppycount);
    SET_GLOBAL(Drives.idmap[EXTTYPE_FLOPPY][floppycount], driveid);
    floppycount++;
    SET_GLOBAL(Drives.floppycount, floppycount);

    // Update equipment word bits for floppy
    if (floppycount == 1) {
        // 1 drive, ready for boot
        SETBITS_BDA(equipment_list_flags, 0x01);
        SET_BDA(floppy_harddisk_info, 0x07);
    } else {
        // 2 drives, ready for boot
        SETBITS_BDA(equipment_list_flags, 0x41);
        SET_BDA(floppy_harddisk_info, 0x77);
    }
}

// Show a one line description (without trailing newline) of a drive.
void
describe_drive(int driveid)
{
    ASSERT32();
    u8 type = GET_GLOBAL(Drives.drives[driveid].type);
    switch (type) {
    case DTYPE_FLOPPY:
        describe_floppy(driveid);
        break;
    case DTYPE_ATA:
        describe_ata(driveid);
        break;
    case DTYPE_ATAPI:
        describe_atapi(driveid);
        break;
    case DTYPE_RAMDISK:
        describe_ramdisk(driveid);
        break;
    default:
        printf("Unknown");
        break;
    }
}


/****************************************************************
 * 16bit calling interface
 ****************************************************************/

// Execute a disk_op request.
static int
process_op(struct disk_op_s *op)
{
    u8 type = GET_GLOBAL(Drives.drives[op->driveid].type);
    switch (type) {
    case DTYPE_FLOPPY:
        return process_floppy_op(op);
    case DTYPE_ATA:
        return process_ata_op(op);
    case DTYPE_ATAPI:
        return process_atapi_op(op);
    case DTYPE_RAMDISK:
        return process_ramdisk_op(op);
    default:
        op->count = 0;
        return DISK_RET_EPARAM;
    }
}

// Execute a "disk_op_s" request - this runs on a stack in the ebda.
static int
__send_disk_op(struct disk_op_s *op_far, u16 op_seg)
{
    struct disk_op_s dop;
    memcpy_far(GET_SEG(SS), &dop
               , op_seg, op_far
               , sizeof(dop));

    dprintf(DEBUG_HDL_13, "disk_op d=%d lba=%d buf=%p count=%d cmd=%d\n"
            , dop.driveid, (u32)dop.lba, dop.buf_fl
            , dop.count, dop.command);

    irq_enable();

    int status = process_op(&dop);

    irq_disable();

    // Update count with total sectors transferred.
    SET_FARVAR(op_seg, op_far->count, dop.count);

    return status;
}

// Execute a "disk_op_s" request by jumping to a stack in the ebda.
int
send_disk_op(struct disk_op_s *op)
{
    if (! CONFIG_DRIVES)
        return -1;
    ASSERT16();

    return stack_hop((u32)op, GET_SEG(SS), 0, __send_disk_op);
}


/****************************************************************
 * Setup
 ****************************************************************/

void
drive_setup()
{
    memset(&Drives, 0, sizeof(Drives));
    memset(&Drives.idmap, 0xff, sizeof(Drives.idmap));
}