Colony » Colony Scout » Colony Scout OS

/*-

 * Copyright (c) 2006, Kohsuke Ohtani

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the author nor the names of any co-contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

/*

 * ramdisk.c - RAM disk driver

 */

#include <driver.h>

/* #define DEBUG_RAMDISK 1 */

#ifdef DEBUG_RAMDISK

#define DPRINTF(a)        printf a

#else

#define DPRINTF(a)

#endif

/* Block size */

#define BSIZE                512

struct ramdisk_softc {

        device_t        dev;                /* device object */

        char                *addr;                /* base address of image */

        size_t                size;                /* image size */

};

static int ramdisk_read(device_t, char *, size_t *, int);

static int ramdisk_write(device_t, char *, size_t *, int);

static int ramdisk_probe(struct driver *);

static int ramdisk_init(struct driver *);

static struct devops ramdisk_devops = {

        /* open */        no_open,

        /* close */        no_close,

        /* read */        ramdisk_read,

        /* write */        ramdisk_write,

        /* ioctl */        no_ioctl,

        /* devctl */        no_devctl,

};

struct driver ramdisk_driver = {

        /* name */        "ramdisk",

        /* devops */        &ramdisk_devops,

        /* devsz */        sizeof(struct ramdisk_softc),

        /* flags */        0,

        /* probe */        ramdisk_probe,

        /* init */        ramdisk_init,

        /* shutdown */        NULL,

};

static int

ramdisk_read(device_t dev, char *buf, size_t *nbyte, int blkno)

{

        struct ramdisk_softc *sc = device_private(dev);

        int offset = blkno * BSIZE;

        void *kbuf;

        size_t nr_read;

        DPRINTF(("ramdisk_read: buf=%x nbyte=%d blkno=%x\n",

                 buf, *nbyte, blkno));

        /* Check overrun */

        if (offset > (int)sc->size) {

                DPRINTF(("ramdisk_read: overrun!\n"));

                return EIO;

        }

        nr_read = *nbyte;

        if (offset + nr_read > (int)sc->size)

                nr_read = sc->size - offset;

        /* Translate buffer address to kernel address */

        if ((kbuf = kmem_map(buf, nr_read)) == NULL) {

                return EFAULT;

        }

        /* Copy data */

        memcpy(kbuf, sc->addr + offset, nr_read);

        *nbyte = nr_read;

        return 0;

}

static int

ramdisk_write(device_t dev, char *buf, size_t *nbyte, int blkno)

{

        struct ramdisk_softc *sc = device_private(dev);

        int offset = blkno * BSIZE;

        void *kbuf;

        size_t nr_write;

        DPRINTF(("ramdisk_write: buf=%x nbyte=%d blkno=%x\n",

                 buf, *nbyte, blkno));

        /* Check overrun */

        if (offset > (int)sc->size)

                return EIO;

        nr_write = *nbyte;

        if (offset + nr_write > (int)sc->size)

                nr_write = sc->size - offset;

        /* Translate buffer address to kernel address */

        if ((kbuf = kmem_map(buf, nr_write)) == NULL)

                return EFAULT;

        /* Copy data */

        memcpy(sc->addr + offset, kbuf, nr_write);

        *nbyte = nr_write;

        return 0;

}

static int

ramdisk_probe(struct driver *self)

{

        struct bootinfo *bi;

        struct physmem *phys;

        machine_bootinfo(&bi);

        phys = &bi->bootdisk;

        if (phys->size == 0) {

#ifdef DEBUG

                printf("ramdisk: no bootdisk found...\n");

#endif

                return ENXIO;

        }

        return 0;

}

static int

ramdisk_init(struct driver *self)

{

        struct ramdisk_softc *sc;

        struct bootinfo *bi;

        struct physmem *phys;

        device_t dev;

        machine_bootinfo(&bi);

        phys = &bi->bootdisk;

        dev = device_create(self, "ram0", D_BLK|D_PROT);

        sc = device_private(dev);

        sc->dev = dev;

        sc->addr = (char *)ptokv(phys->base);

        sc->size = (size_t)phys->size;

#ifdef DEBUG

        printf("RAM disk at 0x%08x (%dK bytes)\n",

               (u_int)sc->addr, sc->size/1024);

#endif

        return 0;

}