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/* ramdisk.c -- RAM disk block device implementation
*
* Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia
* Author: Victor V. Vengerov <vvv@oktet.ru>
*
* @(#) $Id$
*/
#include <rtems.h>
#include <rtems/libio.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "rtems/blkdev.h"
#include "rtems/diskdevs.h"
#include "rtems/ramdisk.h"
#define RAMDISK_DEVICE_BASE_NAME "/dev/ramdisk"
/* Internal RAM disk descriptor */
struct ramdisk {
int block_size; /* RAM disk block size */
int block_num; /* Number of blocks on this RAM disk */
void *area; /* RAM disk memory area */
rtems_boolean initialized;/* RAM disk is initialized */
rtems_boolean malloced; /* != 0, if memory allocated by malloc for this
RAM disk */
};
static struct ramdisk *ramdisk;
static int nramdisks;
/* ramdisk_read --
* RAM disk READ request handler. This primitive copies data from RAM
* disk to supplied buffer and invoke the callout function to inform
* upper layer that reading is completed.
*
* PARAMETERS:
* req - pointer to the READ block device request info
*
* RETURNS:
* ioctl return value
*/
static int
ramdisk_read(struct ramdisk *rd, blkdev_request *req)
{
char *from;
rtems_unsigned32 i;
blkdev_sg_buffer *sg;
rtems_unsigned32 remains;
from = (char *)rd->area + (req->start * rd->block_size);
remains = rd->block_size * req->count;
sg = req->bufs;
for (i = 0; (remains > 0) && (i < req->bufnum); i++, sg++)
{
int count = sg->length;
if (count > remains)
count = remains;
memcpy(sg->buffer, from, count);
remains -= count;
}
req->req_done(req->done_arg, RTEMS_SUCCESSFUL, 0);
return 0;
}
/* ramdisk_write --
* RAM disk WRITE request handler. This primitive copies data from
* supplied buffer to RAM disk and invoke the callout function to inform
* upper layer that writing is completed.
*
* PARAMETERS:
* req - pointer to the WRITE block device request info
*
* RETURNS:
* ioctl return value
*/
static int
ramdisk_write(struct ramdisk *rd, blkdev_request *req)
{
char *to;
rtems_unsigned32 i;
blkdev_sg_buffer *sg;
rtems_unsigned32 remains;
to = (char *)rd->area + (req->start * rd->block_size);
remains = rd->block_size * req->count;
sg = req->bufs;
for (i = 0; (remains > 0) && (i < req->bufnum); i++, sg++)
{
int count = sg->length;
if (count > remains)
count = remains;
memcpy(to, sg->buffer, count);
remains -= count;
}
req->req_done(req->done_arg, RTEMS_SUCCESSFUL, 0);
return 0;
}
/* ramdisk_ioctl --
* IOCTL handler for RAM disk device.
*
* PARAMETERS:
* dev - device number (major, minor number)
* req - IOCTL request code
* argp - IOCTL argument
*
* RETURNS:
* IOCTL return value
*/
static int
ramdisk_ioctl(dev_t dev, int req, void *argp)
{
switch (req)
{
case BLKIO_REQUEST:
{
rtems_device_minor_number minor;
blkdev_request *r = argp;
struct ramdisk *rd;
minor = rtems_filesystem_dev_minor_t(dev);
if ((minor >= nramdisks) || !ramdisk[minor].initialized)
{
errno = ENODEV;
return -1;
}
rd = ramdisk + minor;
switch (r->req)
{
case BLKDEV_REQ_READ:
return ramdisk_read(rd, r);
case BLKDEV_REQ_WRITE:
return ramdisk_write(rd, r);
default:
errno = EBADRQC;
return -1;
}
break;
}
default:
errno = EBADRQC;
return -1;
}
}
/* ramdisk_initialize --
* RAM disk device driver initialization. Run through RAM disk
* configuration information and configure appropriate RAM disks.
*
* PARAMETERS:
* major - RAM disk major device number
* minor - minor device number, not applicable
* arg - initialization argument, not applicable
*
* RETURNS:
* none
*/
rtems_device_driver
ramdisk_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg)
{
rtems_device_minor_number i;
rtems_ramdisk_config *c = rtems_ramdisk_configuration;
struct ramdisk *r;
rtems_status_code rc;
rc = rtems_disk_io_initialize();
if (rc != RTEMS_SUCCESSFUL)
return rc;
r = ramdisk = calloc(rtems_ramdisk_configuration_size,
sizeof(struct ramdisk));
for (i = 0; i < rtems_ramdisk_configuration_size; i++, c++, r++)
{
dev_t dev = rtems_filesystem_make_dev_t(major, i);
char name[sizeof(RAMDISK_DEVICE_BASE_NAME "0123456789")];
snprintf(name, sizeof(name), RAMDISK_DEVICE_BASE_NAME "%d", i);
r->block_size = c->block_size;
r->block_num = c->block_num;
if (c->location == NULL)
{
r->malloced = TRUE;
r->area = malloc(r->block_size * r->block_num);
if (r->area == NULL) /* No enough memory for this disk */
{
r->initialized = FALSE;
continue;
}
else
{
r->initialized = TRUE;
}
}
else
{
r->malloced = FALSE;
r->initialized = TRUE;
r->area = c->location;
}
rc = rtems_disk_create_phys(dev, c->block_size, c->block_num,
ramdisk_ioctl, name);
if (rc != RTEMS_SUCCESSFUL)
{
if (r->malloced)
{
free(r->area);
}
r->initialized = FALSE;
}
}
nramdisks = rtems_ramdisk_configuration_size;
return RTEMS_SUCCESSFUL;
}
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