gdrom.c

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/* GD ROM driver for the SEGA Dreamcast
 * copyright Adrian McMenamin, 2007
 * With thanks to Marcus Comstedt and Nathan Keynes
 * for work in reversing PIO and DMA
 *
 * 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/cdrom.h>
#include <linux/genhd.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <scsi/scsi.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/delay.h>
#include <mach/dma.h>
#include <mach/sysasic.h>

#define GDROM_DEV_NAME "gdrom"
#define GD_SESSION_OFFSET 150

/* GD Rom commands */
#define GDROM_COM_SOFTRESET 0x08
#define GDROM_COM_EXECDIAG 0x90
#define GDROM_COM_PACKET 0xA0
#define GDROM_COM_IDDEV 0xA1

/* GD Rom registers */
#define GDROM_BASE_REG          0xA05F7000
#define GDROM_ALTSTATUS_REG     (GDROM_BASE_REG + 0x18)
#define GDROM_DATA_REG          (GDROM_BASE_REG + 0x80)
#define GDROM_ERROR_REG     (GDROM_BASE_REG + 0x84)
#define GDROM_INTSEC_REG        (GDROM_BASE_REG + 0x88)
#define GDROM_SECNUM_REG        (GDROM_BASE_REG + 0x8C)
#define GDROM_BCL_REG           (GDROM_BASE_REG + 0x90)
#define GDROM_BCH_REG           (GDROM_BASE_REG + 0x94)
#define GDROM_DSEL_REG          (GDROM_BASE_REG + 0x98)
#define GDROM_STATUSCOMMAND_REG (GDROM_BASE_REG + 0x9C)
#define GDROM_RESET_REG     (GDROM_BASE_REG + 0x4E4)

#define GDROM_DMA_STARTADDR_REG (GDROM_BASE_REG + 0x404)
#define GDROM_DMA_LENGTH_REG        (GDROM_BASE_REG + 0x408)
#define GDROM_DMA_DIRECTION_REG (GDROM_BASE_REG + 0x40C)
#define GDROM_DMA_ENABLE_REG        (GDROM_BASE_REG + 0x414)
#define GDROM_DMA_STATUS_REG        (GDROM_BASE_REG + 0x418)
#define GDROM_DMA_WAIT_REG      (GDROM_BASE_REG + 0x4A0)
#define GDROM_DMA_ACCESS_CTRL_REG   (GDROM_BASE_REG + 0x4B8)

#define GDROM_HARD_SECTOR   2048
#define BLOCK_LAYER_SECTOR  512
#define GD_TO_BLK       4

#define GDROM_DEFAULT_TIMEOUT   (HZ * 7)

static DEFINE_MUTEX(gdrom_mutex);
static const struct {
    int sense_key;
    const char * const text;
} sense_texts[] = {
    {NO_SENSE, "OK"},
    {RECOVERED_ERROR, "Recovered from error"},
    {NOT_READY, "Device not ready"},
    {MEDIUM_ERROR, "Disk not ready"},
    {HARDWARE_ERROR, "Hardware error"},
    {ILLEGAL_REQUEST, "Command has failed"},
    {UNIT_ATTENTION, "Device needs attention - disk may have been changed"},
    {DATA_PROTECT, "Data protection error"},
    {ABORTED_COMMAND, "Command aborted"},
};

static struct platform_device *pd;
static int gdrom_major;
static DECLARE_WAIT_QUEUE_HEAD(command_queue);
static DECLARE_WAIT_QUEUE_HEAD(request_queue);

static DEFINE_SPINLOCK(gdrom_lock);
static void gdrom_readdisk_dma(struct work_struct *work);
static DECLARE_WORK(work, gdrom_readdisk_dma);
static LIST_HEAD(gdrom_deferred);

struct gdromtoc {
    unsigned int entry[99];
    unsigned int first, last;
    unsigned int leadout;
};

static struct gdrom_unit {
    struct gendisk *disk;
    struct cdrom_device_info *cd_info;
    int status;
    int pending;
    int transfer;
    char disk_type;
    struct gdromtoc *toc;
    struct request_queue *gdrom_rq;
} gd;

struct gdrom_id {
    char mid;
    char modid;
    char verid;
    char padA[13];
    char mname[16];
    char modname[16];
    char firmver[16];
    char padB[16];
};

static int gdrom_getsense(short *bufstring);
static int gdrom_packetcommand(struct cdrom_device_info *cd_info,
    struct packet_command *command);
static int gdrom_hardreset(struct cdrom_device_info *cd_info);

static bool gdrom_is_busy(void)
{
    return (__raw_readb(GDROM_ALTSTATUS_REG) & 0x80) != 0;
}

static bool gdrom_data_request(void)
{
    return (__raw_readb(GDROM_ALTSTATUS_REG) & 0x88) == 8;
}

static bool gdrom_wait_clrbusy(void)
{
    unsigned long timeout = jiffies + GDROM_DEFAULT_TIMEOUT;
    while ((__raw_readb(GDROM_ALTSTATUS_REG) & 0x80) &&
        (time_before(jiffies, timeout)))
        cpu_relax();
    return time_before(jiffies, timeout + 1);
}

static bool gdrom_wait_busy_sleeps(void)
{
    unsigned long timeout;
    /* Wait to get busy first */
    timeout = jiffies + GDROM_DEFAULT_TIMEOUT;
    while (!gdrom_is_busy() && time_before(jiffies, timeout))
        cpu_relax();
    /* Now wait for busy to clear */
    return gdrom_wait_clrbusy();
}

static void gdrom_identifydevice(void *buf)
{
    int c;
    short *data = buf;
    /* If the device won't clear it has probably
    * been hit by a serious failure - but we'll
    * try to return a sense key even so */
    if (!gdrom_wait_clrbusy()) {
        gdrom_getsense(NULL);
        return;
    }
    __raw_writeb(GDROM_COM_IDDEV, GDROM_STATUSCOMMAND_REG);
    if (!gdrom_wait_busy_sleeps()) {
        gdrom_getsense(NULL);
        return;
    }
    /* now read in the data */
    for (c = 0; c < 40; c++)
        data[c] = __raw_readw(GDROM_DATA_REG);
}

static void gdrom_spicommand(void *spi_string, int buflen)
{
    short *cmd = spi_string;
    unsigned long timeout;

    /* ensure IRQ_WAIT is set */
    __raw_writeb(0x08, GDROM_ALTSTATUS_REG);
    /* specify how many bytes we expect back */
    __raw_writeb(buflen & 0xFF, GDROM_BCL_REG);
    __raw_writeb((buflen >> 8) & 0xFF, GDROM_BCH_REG);
    /* other parameters */
    __raw_writeb(0, GDROM_INTSEC_REG);
    __raw_writeb(0, GDROM_SECNUM_REG);
    __raw_writeb(0, GDROM_ERROR_REG);
    /* Wait until we can go */
    if (!gdrom_wait_clrbusy()) {
        gdrom_getsense(NULL);
        return;
    }
    timeout = jiffies + GDROM_DEFAULT_TIMEOUT;
    __raw_writeb(GDROM_COM_PACKET, GDROM_STATUSCOMMAND_REG);
    while (!gdrom_data_request() && time_before(jiffies, timeout))
        cpu_relax();
    if (!time_before(jiffies, timeout + 1)) {
        gdrom_getsense(NULL);
        return;
    }
    outsw(GDROM_DATA_REG, cmd, 6);
}


/* gdrom_command_executediagnostic:
 * Used to probe for presence of working GDROM
 * Restarts GDROM device and then applies standard ATA 3
 * Execute Diagnostic Command: a return of '1' indicates device 0
 * present and device 1 absent
 */
static char gdrom_execute_diagnostic(void)
{
    gdrom_hardreset(gd.cd_info);
    if (!gdrom_wait_clrbusy())
        return 0;
    __raw_writeb(GDROM_COM_EXECDIAG, GDROM_STATUSCOMMAND_REG);
    if (!gdrom_wait_busy_sleeps())
        return 0;
    return __raw_readb(GDROM_ERROR_REG);
}

/*
 * Prepare disk command
 * byte 0 = 0x70
 * byte 1 = 0x1f
 */
static int gdrom_preparedisk_cmd(void)
{
    struct packet_command *spin_command;
    spin_command = kzalloc(sizeof(struct packet_command), GFP_KERNEL);
    if (!spin_command)
        return -ENOMEM;
    spin_command->cmd[0] = 0x70;
    spin_command->cmd[2] = 0x1f;
    spin_command->buflen = 0;
    gd.pending = 1;
    gdrom_packetcommand(gd.cd_info, spin_command);
    /* 60 second timeout */
    wait_event_interruptible_timeout(command_queue, gd.pending == 0,
        GDROM_DEFAULT_TIMEOUT);
    gd.pending = 0;
    kfree(spin_command);
    if (gd.status & 0x01) {
        /* log an error */
        gdrom_getsense(NULL);
        return -EIO;
    }
    return 0;
}

/*
 * Read TOC command
 * byte 0 = 0x14
 * byte 1 = session
 * byte 3 = sizeof TOC >> 8  ie upper byte
 * byte 4 = sizeof TOC & 0xff ie lower byte
 */
static int gdrom_readtoc_cmd(struct gdromtoc *toc, int session)
{
    int tocsize;
    struct packet_command *toc_command;
    int err = 0;

    toc_command = kzalloc(sizeof(struct packet_command), GFP_KERNEL);
    if (!toc_command)
        return -ENOMEM;
    tocsize = sizeof(struct gdromtoc);
    toc_command->cmd[0] = 0x14;
    toc_command->cmd[1] = session;
    toc_command->cmd[3] = tocsize >> 8;
    toc_command->cmd[4] = tocsize & 0xff;
    toc_command->buflen = tocsize;
    if (gd.pending) {
        err = -EBUSY;
        goto cleanup_readtoc_final;
    }
    gd.pending = 1;
    gdrom_packetcommand(gd.cd_info, toc_command);
    wait_event_interruptible_timeout(command_queue, gd.pending == 0,
        GDROM_DEFAULT_TIMEOUT);
    if (gd.pending) {
        err = -EINVAL;
        goto cleanup_readtoc;
    }
    insw(GDROM_DATA_REG, toc, tocsize/2);
    if (gd.status & 0x01)
        err = -EINVAL;

cleanup_readtoc:
    gd.pending = 0;
cleanup_readtoc_final:
    kfree(toc_command);
    return err;
}

/* TOC helpers */
static int get_entry_lba(int track)
{
    return (cpu_to_be32(track & 0xffffff00) - GD_SESSION_OFFSET);
}

static int get_entry_q_ctrl(int track)
{
    return (track & 0x000000f0) >> 4;
}

static int get_entry_track(int track)
{
    return (track & 0x0000ff00) >> 8;
}

static int gdrom_get_last_session(struct cdrom_device_info *cd_info,
    struct cdrom_multisession *ms_info)
{
    int fentry, lentry, track, data, tocuse, err;
    if (!gd.toc)
        return -ENOMEM;
    tocuse = 1;
    /* Check if GD-ROM */
    err = gdrom_readtoc_cmd(gd.toc, 1);
    /* Not a GD-ROM so check if standard CD-ROM */
    if (err) {
        tocuse = 0;
        err = gdrom_readtoc_cmd(gd.toc, 0);
        if (err) {
            pr_info("Could not get CD table of contents\n");
            return -ENXIO;
        }
    }

    fentry = get_entry_track(gd.toc->first);
    lentry = get_entry_track(gd.toc->last);
    /* Find the first data track */
    track = get_entry_track(gd.toc->last);
    do {
        data = gd.toc->entry[track - 1];
        if (get_entry_q_ctrl(data))
            break;  /* ie a real data track */
        track--;
    } while (track >= fentry);

    if ((track > 100) || (track < get_entry_track(gd.toc->first))) {
        pr_info("No data on the last session of the CD\n");
        gdrom_getsense(NULL);
        return -ENXIO;
    }

    ms_info->addr_format = CDROM_LBA;
    ms_info->addr.lba = get_entry_lba(data);
    ms_info->xa_flag = 1;
    return 0;
}

static int gdrom_open(struct cdrom_device_info *cd_info, int purpose)
{
    /* spin up the disk */
    return gdrom_preparedisk_cmd();
}

/* this function is required even if empty */
static void gdrom_release(struct cdrom_device_info *cd_info)
{
}

static int gdrom_drivestatus(struct cdrom_device_info *cd_info, int ignore)
{
    /* read the sense key */
    char sense = __raw_readb(GDROM_ERROR_REG);
    sense &= 0xF0;
    if (sense == 0)
        return CDS_DISC_OK;
    if (sense == 0x20)
        return CDS_DRIVE_NOT_READY;
    /* default */
    return CDS_NO_INFO;
}

static unsigned int gdrom_check_events(struct cdrom_device_info *cd_info,
                       unsigned int clearing, int ignore)
{
    /* check the sense key */
    return (__raw_readb(GDROM_ERROR_REG) & 0xF0) == 0x60 ?
        DISK_EVENT_MEDIA_CHANGE : 0;
}

/* reset the G1 bus */
static int gdrom_hardreset(struct cdrom_device_info *cd_info)
{
    int count;
    __raw_writel(0x1fffff, GDROM_RESET_REG);
    for (count = 0xa0000000; count < 0xa0200000; count += 4)
        __raw_readl(count);
    return 0;
}

/* keep the function looking like the universal
 * CD Rom specification  - returning int */
static int gdrom_packetcommand(struct cdrom_device_info *cd_info,
    struct packet_command *command)
{
    gdrom_spicommand(&command->cmd, command->buflen);
    return 0;
}

/* Get Sense SPI command
 * From Marcus Comstedt
 * cmd = 0x13
 * cmd + 4 = length of returned buffer
 * Returns 5 16 bit words
 */
static int gdrom_getsense(short *bufstring)
{
    struct packet_command *sense_command;
    short sense[5];
    int sense_key;
    int err = -EIO;

    sense_command = kzalloc(sizeof(struct packet_command), GFP_KERNEL);
    if (!sense_command)
        return -ENOMEM;
    sense_command->cmd[0] = 0x13;
    sense_command->cmd[4] = 10;
    sense_command->buflen = 10;
    /* even if something is pending try to get
    * the sense key if possible */
    if (gd.pending && !gdrom_wait_clrbusy()) {
        err = -EBUSY;
        goto cleanup_sense_final;
    }
    gd.pending = 1;
    gdrom_packetcommand(gd.cd_info, sense_command);
    wait_event_interruptible_timeout(command_queue, gd.pending == 0,
        GDROM_DEFAULT_TIMEOUT);
    if (gd.pending)
        goto cleanup_sense;
    insw(GDROM_DATA_REG, &sense, sense_command->buflen/2);
    if (sense[1] & 40) {
        pr_info("Drive not ready - command aborted\n");
        goto cleanup_sense;
    }
    sense_key = sense[1] & 0x0F;
    if (sense_key < ARRAY_SIZE(sense_texts))
        pr_info("%s\n", sense_texts[sense_key].text);
    else
        pr_err("Unknown sense key: %d\n", sense_key);
    if (bufstring) /* return addional sense data */
        memcpy(bufstring, &sense[4], 2);
    if (sense_key < 2)
        err = 0;

cleanup_sense:
    gd.pending = 0;
cleanup_sense_final:
    kfree(sense_command);
    return err;
}

static int gdrom_audio_ioctl(struct cdrom_device_info *cdi, unsigned int cmd,
                 void *arg)
{
    return -EINVAL;
}

static struct cdrom_device_ops gdrom_ops = {
    .open           = gdrom_open,
    .release        = gdrom_release,
    .drive_status       = gdrom_drivestatus,
    .check_events       = gdrom_check_events,
    .get_last_session   = gdrom_get_last_session,
    .reset          = gdrom_hardreset,
    .audio_ioctl        = gdrom_audio_ioctl,
    .capability     = CDC_MULTI_SESSION | CDC_MEDIA_CHANGED |
                  CDC_RESET | CDC_DRIVE_STATUS | CDC_CD_R,
    .n_minors       = 1,
};

static int gdrom_bdops_open(struct block_device *bdev, fmode_t mode)
{
    int ret;
    mutex_lock(&gdrom_mutex);
    ret = cdrom_open(gd.cd_info, bdev, mode);
    mutex_unlock(&gdrom_mutex);
    return ret;
}

static int gdrom_bdops_release(struct gendisk *disk, fmode_t mode)
{
    mutex_lock(&gdrom_mutex);
    cdrom_release(gd.cd_info, mode);
    mutex_unlock(&gdrom_mutex);
    return 0;
}

static unsigned int gdrom_bdops_check_events(struct gendisk *disk,
                         unsigned int clearing)
{
    return cdrom_check_events(gd.cd_info, clearing);
}

static int gdrom_bdops_ioctl(struct block_device *bdev, fmode_t mode,
    unsigned cmd, unsigned long arg)
{
    int ret;

    mutex_lock(&gdrom_mutex);
    ret = cdrom_ioctl(gd.cd_info, bdev, mode, cmd, arg);
    mutex_unlock(&gdrom_mutex);

    return ret;
}

static const struct block_device_operations gdrom_bdops = {
    .owner          = THIS_MODULE,
    .open           = gdrom_bdops_open,
    .release        = gdrom_bdops_release,
    .check_events       = gdrom_bdops_check_events,
    .ioctl          = gdrom_bdops_ioctl,
};

static irqreturn_t gdrom_command_interrupt(int irq, void *dev_id)
{
    gd.status = __raw_readb(GDROM_STATUSCOMMAND_REG);
    if (gd.pending != 1)
        return IRQ_HANDLED;
    gd.pending = 0;
    wake_up_interruptible(&command_queue);
    return IRQ_HANDLED;
}

static irqreturn_t gdrom_dma_interrupt(int irq, void *dev_id)
{
    gd.status = __raw_readb(GDROM_STATUSCOMMAND_REG);
    if (gd.transfer != 1)
        return IRQ_HANDLED;
    gd.transfer = 0;
    wake_up_interruptible(&request_queue);
    return IRQ_HANDLED;
}

static int __devinit gdrom_set_interrupt_handlers(void)
{
    int err;

    err = request_irq(HW_EVENT_GDROM_CMD, gdrom_command_interrupt,
        IRQF_DISABLED, "gdrom_command", &gd);
    if (err)
        return err;
    err = request_irq(HW_EVENT_GDROM_DMA, gdrom_dma_interrupt,
        IRQF_DISABLED, "gdrom_dma", &gd);
    if (err)
        free_irq(HW_EVENT_GDROM_CMD, &gd);
    return err;
}

/* Implement DMA read using SPI command
 * 0 -> 0x30
 * 1 -> mode
 * 2 -> block >> 16
 * 3 -> block >> 8
 * 4 -> block
 * 8 -> sectors >> 16
 * 9 -> sectors >> 8
 * 10 -> sectors
 */
static void gdrom_readdisk_dma(struct work_struct *work)
{
    int err, block, block_cnt;
    struct packet_command *read_command;
    struct list_head *elem, *next;
    struct request *req;
    unsigned long timeout;

    if (list_empty(&gdrom_deferred))
        return;
    read_command = kzalloc(sizeof(struct packet_command), GFP_KERNEL);
    if (!read_command)
        return; /* get more memory later? */
    read_command->cmd[0] = 0x30;
    read_command->cmd[1] = 0x20;
    spin_lock(&gdrom_lock);
    list_for_each_safe(elem, next, &gdrom_deferred) {
        req = list_entry(elem, struct request, queuelist);
        spin_unlock(&gdrom_lock);
        block = blk_rq_pos(req)/GD_TO_BLK + GD_SESSION_OFFSET;
        block_cnt = blk_rq_sectors(req)/GD_TO_BLK;
        __raw_writel(virt_to_phys(req->buffer), GDROM_DMA_STARTADDR_REG);
        __raw_writel(block_cnt * GDROM_HARD_SECTOR, GDROM_DMA_LENGTH_REG);
        __raw_writel(1, GDROM_DMA_DIRECTION_REG);
        __raw_writel(1, GDROM_DMA_ENABLE_REG);
        read_command->cmd[2] = (block >> 16) & 0xFF;
        read_command->cmd[3] = (block >> 8) & 0xFF;
        read_command->cmd[4] = block & 0xFF;
        read_command->cmd[8] = (block_cnt >> 16) & 0xFF;
        read_command->cmd[9] = (block_cnt >> 8) & 0xFF;
        read_command->cmd[10] = block_cnt & 0xFF;
        /* set for DMA */
        __raw_writeb(1, GDROM_ERROR_REG);
        /* other registers */
        __raw_writeb(0, GDROM_SECNUM_REG);
        __raw_writeb(0, GDROM_BCL_REG);
        __raw_writeb(0, GDROM_BCH_REG);
        __raw_writeb(0, GDROM_DSEL_REG);
        __raw_writeb(0, GDROM_INTSEC_REG);
        /* Wait for registers to reset after any previous activity */
        timeout = jiffies + HZ / 2;
        while (gdrom_is_busy() && time_before(jiffies, timeout))
            cpu_relax();
        __raw_writeb(GDROM_COM_PACKET, GDROM_STATUSCOMMAND_REG);
        timeout = jiffies + HZ / 2;
        /* Wait for packet command to finish */
        while (gdrom_is_busy() && time_before(jiffies, timeout))
            cpu_relax();
        gd.pending = 1;
        gd.transfer = 1;
        outsw(GDROM_DATA_REG, &read_command->cmd, 6);
        timeout = jiffies + HZ / 2;
        /* Wait for any pending DMA to finish */
        while (__raw_readb(GDROM_DMA_STATUS_REG) &&
            time_before(jiffies, timeout))
            cpu_relax();
        /* start transfer */
        __raw_writeb(1, GDROM_DMA_STATUS_REG);
        wait_event_interruptible_timeout(request_queue,
            gd.transfer == 0, GDROM_DEFAULT_TIMEOUT);
        err = gd.transfer ? -EIO : 0;
        gd.transfer = 0;
        gd.pending = 0;
        /* now seek to take the request spinlock
        * before handling ending the request */
        spin_lock(&gdrom_lock);
        list_del_init(&req->queuelist);
        __blk_end_request_all(req, err);
    }
    spin_unlock(&gdrom_lock);
    kfree(read_command);
}

static void gdrom_request(struct request_queue *rq)
{
    struct request *req;

    while ((req = blk_fetch_request(rq)) != NULL) {
        if (req->cmd_type != REQ_TYPE_FS) {
            printk(KERN_DEBUG "gdrom: Non-fs request ignored\n");
            __blk_end_request_all(req, -EIO);
            continue;
        }
        if (rq_data_dir(req) != READ) {
            pr_notice("Read only device - write request ignored\n");
            __blk_end_request_all(req, -EIO);
            continue;
        }

        /*
         * Add to list of deferred work and then schedule
         * workqueue.
         */
        list_add_tail(&req->queuelist, &gdrom_deferred);
        schedule_work(&work);
    }
}

/* Print string identifying GD ROM device */
static int __devinit gdrom_outputversion(void)
{
    struct gdrom_id *id;
    char *model_name, *manuf_name, *firmw_ver;
    int err = -ENOMEM;

    /* query device ID */
    id = kzalloc(sizeof(struct gdrom_id), GFP_KERNEL);
    if (!id)
        return err;
    gdrom_identifydevice(id);
    model_name = kstrndup(id->modname, 16, GFP_KERNEL);
    if (!model_name)
        goto free_id;
    manuf_name = kstrndup(id->mname, 16, GFP_KERNEL);
    if (!manuf_name)
        goto free_model_name;
    firmw_ver = kstrndup(id->firmver, 16, GFP_KERNEL);
    if (!firmw_ver)
        goto free_manuf_name;
    pr_info("%s from %s with firmware %s\n",
        model_name, manuf_name, firmw_ver);
    err = 0;
    kfree(firmw_ver);
free_manuf_name:
    kfree(manuf_name);
free_model_name:
    kfree(model_name);
free_id:
    kfree(id);
    return err;
}

/* set the default mode for DMA transfer */
static int __devinit gdrom_init_dma_mode(void)
{
    __raw_writeb(0x13, GDROM_ERROR_REG);
    __raw_writeb(0x22, GDROM_INTSEC_REG);
    if (!gdrom_wait_clrbusy())
        return -EBUSY;
    __raw_writeb(0xEF, GDROM_STATUSCOMMAND_REG);
    if (!gdrom_wait_busy_sleeps())
        return -EBUSY;
    /* Memory protection setting for GDROM DMA
    * Bits 31 - 16 security: 0x8843
    * Bits 15 and 7 reserved (0)
    * Bits 14 - 8 start of transfer range in 1 MB blocks OR'ed with 0x80
    * Bits 6 - 0 end of transfer range in 1 MB blocks OR'ed with 0x80
    * (0x40 | 0x80) = start range at 0x0C000000
    * (0x7F | 0x80) = end range at 0x0FFFFFFF */
    __raw_writel(0x8843407F, GDROM_DMA_ACCESS_CTRL_REG);
    __raw_writel(9, GDROM_DMA_WAIT_REG); /* DMA word setting */
    return 0;
}

static void __devinit probe_gdrom_setupcd(void)
{
    gd.cd_info->ops = &gdrom_ops;
    gd.cd_info->capacity = 1;
    strcpy(gd.cd_info->name, GDROM_DEV_NAME);
    gd.cd_info->mask = CDC_CLOSE_TRAY|CDC_OPEN_TRAY|CDC_LOCK|
        CDC_SELECT_DISC;
}

static void __devinit probe_gdrom_setupdisk(void)
{
    gd.disk->major = gdrom_major;
    gd.disk->first_minor = 1;
    gd.disk->minors = 1;
    strcpy(gd.disk->disk_name, GDROM_DEV_NAME);
}

static int __devinit probe_gdrom_setupqueue(void)
{
    blk_queue_logical_block_size(gd.gdrom_rq, GDROM_HARD_SECTOR);
    /* using DMA so memory will need to be contiguous */
    blk_queue_max_segments(gd.gdrom_rq, 1);
    /* set a large max size to get most from DMA */
    blk_queue_max_segment_size(gd.gdrom_rq, 0x40000);
    gd.disk->queue = gd.gdrom_rq;
    return gdrom_init_dma_mode();
}

/*
 * register this as a block device and as compliant with the
 * universal CD Rom driver interface
 */
static int __devinit probe_gdrom(struct platform_device *devptr)
{
    int err;
    /* Start the device */
    if (gdrom_execute_diagnostic() != 1) {
        pr_warning("ATA Probe for GDROM failed\n");
        return -ENODEV;
    }
    /* Print out firmware ID */
    if (gdrom_outputversion())
        return -ENOMEM;
    /* Register GDROM */
    gdrom_major = register_blkdev(0, GDROM_DEV_NAME);
    if (gdrom_major <= 0)
        return gdrom_major;
    pr_info("Registered with major number %d\n",
        gdrom_major);
    /* Specify basic properties of drive */
    gd.cd_info = kzalloc(sizeof(struct cdrom_device_info), GFP_KERNEL);
    if (!gd.cd_info) {
        err = -ENOMEM;
        goto probe_fail_no_mem;
    }
    probe_gdrom_setupcd();
    gd.disk = alloc_disk(1);
    if (!gd.disk) {
        err = -ENODEV;
        goto probe_fail_no_disk;
    }
    probe_gdrom_setupdisk();
    if (register_cdrom(gd.cd_info)) {
        err = -ENODEV;
        goto probe_fail_cdrom_register;
    }
    gd.disk->fops = &gdrom_bdops;
    /* latch on to the interrupt */
    err = gdrom_set_interrupt_handlers();
    if (err)
        goto probe_fail_cmdirq_register;
    gd.gdrom_rq = blk_init_queue(gdrom_request, &gdrom_lock);
    if (!gd.gdrom_rq)
        goto probe_fail_requestq;

    err = probe_gdrom_setupqueue();
    if (err)
        goto probe_fail_toc;

    gd.toc = kzalloc(sizeof(struct gdromtoc), GFP_KERNEL);
    if (!gd.toc)
        goto probe_fail_toc;
    add_disk(gd.disk);
    return 0;

probe_fail_toc:
    blk_cleanup_queue(gd.gdrom_rq);
probe_fail_requestq:
    free_irq(HW_EVENT_GDROM_DMA, &gd);
    free_irq(HW_EVENT_GDROM_CMD, &gd);
probe_fail_cmdirq_register:
probe_fail_cdrom_register:
    del_gendisk(gd.disk);
probe_fail_no_disk:
    kfree(gd.cd_info);
    unregister_blkdev(gdrom_major, GDROM_DEV_NAME);
    gdrom_major = 0;
probe_fail_no_mem:
    pr_warning("Probe failed - error is 0x%X\n", err);
    return err;
}

static int __devexit remove_gdrom(struct platform_device *devptr)
{
    flush_work(&work);
    blk_cleanup_queue(gd.gdrom_rq);
    free_irq(HW_EVENT_GDROM_CMD, &gd);
    free_irq(HW_EVENT_GDROM_DMA, &gd);
    del_gendisk(gd.disk);
    if (gdrom_major)
        unregister_blkdev(gdrom_major, GDROM_DEV_NAME);
    unregister_cdrom(gd.cd_info);

    return 0;
}

static struct platform_driver gdrom_driver = {
    .probe = probe_gdrom,
    .remove = __devexit_p(remove_gdrom),
    .driver = {
            .name = GDROM_DEV_NAME,
    },
};

static int __init init_gdrom(void)
{
    int rc;
    gd.toc = NULL;
    rc = platform_driver_register(&gdrom_driver);
    if (rc)
        return rc;
    pd = platform_device_register_simple(GDROM_DEV_NAME, -1, NULL, 0);
    if (IS_ERR(pd)) {
        platform_driver_unregister(&gdrom_driver);
        return PTR_ERR(pd);
    }
    return 0;
}

static void __exit exit_gdrom(void)
{
    platform_device_unregister(pd);
    platform_driver_unregister(&gdrom_driver);
    kfree(gd.toc);
}

module_init(init_gdrom);
module_exit(exit_gdrom);
MODULE_AUTHOR("Adrian McMenamin <[email protected]>");
MODULE_DESCRIPTION("SEGA Dreamcast GD-ROM Driver");
MODULE_LICENSE("GPL");