scoutos / prex-0.9.0 / bsp / drv / dev / block / ramdisk.c @ 03e9c04a
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/*-
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* Copyright (c) 2006, Kohsuke Ohtani
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* ramdisk.c - RAM disk driver
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*/
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#include <driver.h> |
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/* #define DEBUG_RAMDISK 1 */
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#ifdef DEBUG_RAMDISK
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#define DPRINTF(a) printf a
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#else
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#define DPRINTF(a)
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#endif
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/* Block size */
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#define BSIZE 512 |
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struct ramdisk_softc {
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device_t dev; /* device object */
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char *addr; /* base address of image */ |
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size_t size; /* image size */
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}; |
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static int ramdisk_read(device_t, char *, size_t *, int); |
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static int ramdisk_write(device_t, char *, size_t *, int); |
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static int ramdisk_probe(struct driver *); |
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static int ramdisk_init(struct driver *); |
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static struct devops ramdisk_devops = { |
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/* open */ no_open,
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/* close */ no_close,
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/* read */ ramdisk_read,
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/* write */ ramdisk_write,
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/* ioctl */ no_ioctl,
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/* devctl */ no_devctl,
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}; |
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struct driver ramdisk_driver = {
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/* name */ "ramdisk", |
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/* devops */ &ramdisk_devops,
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/* devsz */ sizeof(struct ramdisk_softc), |
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/* flags */ 0, |
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/* probe */ ramdisk_probe,
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/* init */ ramdisk_init,
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/* shutdown */ NULL, |
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}; |
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static int |
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ramdisk_read(device_t dev, char *buf, size_t *nbyte, int blkno) |
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{ |
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struct ramdisk_softc *sc = device_private(dev);
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int offset = blkno * BSIZE;
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void *kbuf;
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size_t nr_read; |
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DPRINTF(("ramdisk_read: buf=%x nbyte=%d blkno=%x\n",
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buf, *nbyte, blkno)); |
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/* Check overrun */
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if (offset > (int)sc->size) { |
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DPRINTF(("ramdisk_read: overrun!\n"));
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return EIO;
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} |
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nr_read = *nbyte; |
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if (offset + nr_read > (int)sc->size) |
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nr_read = sc->size - offset; |
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/* Translate buffer address to kernel address */
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if ((kbuf = kmem_map(buf, nr_read)) == NULL) { |
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return EFAULT;
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} |
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/* Copy data */
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memcpy(kbuf, sc->addr + offset, nr_read); |
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*nbyte = nr_read; |
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return 0; |
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} |
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static int |
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ramdisk_write(device_t dev, char *buf, size_t *nbyte, int blkno) |
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{ |
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struct ramdisk_softc *sc = device_private(dev);
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int offset = blkno * BSIZE;
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void *kbuf;
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size_t nr_write; |
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DPRINTF(("ramdisk_write: buf=%x nbyte=%d blkno=%x\n",
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buf, *nbyte, blkno)); |
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/* Check overrun */
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if (offset > (int)sc->size) |
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return EIO;
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nr_write = *nbyte; |
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if (offset + nr_write > (int)sc->size) |
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nr_write = sc->size - offset; |
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/* Translate buffer address to kernel address */
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if ((kbuf = kmem_map(buf, nr_write)) == NULL) |
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return EFAULT;
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/* Copy data */
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memcpy(sc->addr + offset, kbuf, nr_write); |
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*nbyte = nr_write; |
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return 0; |
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} |
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static int |
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ramdisk_probe(struct driver *self)
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{ |
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struct bootinfo *bi;
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struct physmem *phys;
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machine_bootinfo(&bi); |
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phys = &bi->bootdisk; |
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if (phys->size == 0) { |
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#ifdef DEBUG
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printf("ramdisk: no bootdisk found...\n");
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#endif
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return ENXIO;
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} |
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return 0; |
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} |
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static int |
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ramdisk_init(struct driver *self)
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{ |
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struct ramdisk_softc *sc;
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struct bootinfo *bi;
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struct physmem *phys;
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device_t dev; |
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machine_bootinfo(&bi); |
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phys = &bi->bootdisk; |
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dev = device_create(self, "ram0", D_BLK|D_PROT);
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sc = device_private(dev); |
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sc->dev = dev; |
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sc->addr = (char *)ptokv(phys->base);
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sc->size = (size_t)phys->size; |
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#ifdef DEBUG
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printf("RAM disk at 0x%08x (%dK bytes)\n",
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(u_int)sc->addr, sc->size/1024);
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#endif
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return 0; |
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} |