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/**
* @file
*
* @ingroup rtems_disk
*
* Block device disk management.
*/
/*
* Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia
* Author: Victor V. Vengerov <vvv@oktet.ru>
*
* @(#) $Id$
*/
#ifndef _RTEMS_DISKDEVS_H
#define _RTEMS_DISKDEVS_H
#include <rtems.h>
#include <rtems/libio.h>
#include <stdlib.h>
#include <rtems/blkdev.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup rtems_disk Block Device Disk Management
*
* @ingroup rtems_libblock
*
* This module provides functions to manage disk devices.
*
* A disk is a set of blocks which are identified by a consecutive set of
* non-negative integers starting at zero. There are also logical disks which
* contain a subset of consecutive disk blocks. The logical disks are used to
* represent the partitions of a disk. The disk devices are accessed via the
* @ref rtems_bdbuf "block device buffer module".
*
* @{
*/
/**
* Block device IO control handler type.
*/
typedef int (*rtems_block_device_ioctl)( dev_t dev, uint32_t req, void *argp);
/**
* Description of a disk device (logical and physical disks).
*
* An array of pointer tables to rtems_disk_device structures is maintained.
* The first table will be indexed by the major number and the second table
* will be indexed by the minor number. This allows quick lookup using a data
* structure of moderated size.
*/
typedef struct rtems_disk_device {
/**
* Device identifier (concatenation of major and minor number).
*/
dev_t dev;
/**
* Physical device identifier (equals the @c dev entry if it specifies a
* physical device).
*/
struct rtems_disk_device *phys_dev;
/**
* Driver capabilities.
*/
uint32_t capabilities;
/**
* Disk device name.
*/
char *name;
/**
* Usage counter.
*
* Devices cannot be removed if they are in use.
*/
unsigned uses;
/**
* Start block number.
*
* Equals zero for physical devices. It is a block offset to the related
* physical device for logical device.
*/
rtems_blkdev_bnum start;
/**
* Size of the physical or logical disk in blocks.
*/
rtems_blkdev_bnum size;
/**
* Device block size in bytes.
*
* This is the minimum transfer unit. It can be any size.
*/
uint32_t block_size;
/**
* Device media block size in bytes.
*
* This is the media transfer unit the hardware defaults to.
*/
uint32_t media_block_size;
/**
* IO control handler for this disk.
*/
rtems_block_device_ioctl ioctl;
} rtems_disk_device;
/**
* Creates a physical disk with device identifier @a dev.
*
* The block size @a block_size must be a power of two. The disk size @a
* disk_size is the number of blocks provided by this disk. The block index
* starts with zero. The associated disk device driver will be invoked via the
* IO control handler @a handler. A device node will be registered in the file
* system with absolute path @a name. This function is usually invoked from a
* block device driver during initialization when a physical device is detected
* in the system. The device driver provides an IO control handler to allow
* block device operations.
*/
rtems_status_code rtems_disk_create_phys(
dev_t dev,
uint32_t block_size,
rtems_blkdev_bnum disk_size,
rtems_block_device_ioctl handler,
const char *name
);
/**
* Creates a logical disk with device identifier @a dev.
*
* A logical disk manages a subset of consecutive blocks containd in the
* physical disk with identifier @a phys. The start block index of the logical
* disk device is @a start. The block number of the logcal disk will be @a
* size. The blocks must be within the range of blocks managed by the
* associated physical disk device. A device node will be registered in the
* file system with absolute path @a name. The block size and IO control
* handler are inherited by the physical disk.
*/
rtems_status_code rtems_disk_create_log(
dev_t dev,
dev_t phys,
rtems_blkdev_bnum start,
rtems_blkdev_bnum size,
const char *name
);
/**
* Deletes a physical or logical disk device with identifier @a dev.
*
* Disk devices may be deleted if there usage counter (and the usage counters
* of all contained logical disks devices) equals zero. When a physical disk
* device is deleted, all logical disk devices will deleted too. The
* corresponding device nodes will be removed from the file system.
*/
rtems_status_code rtems_disk_delete(dev_t dev);
/**
* Returns the disk device descriptor for the device identifier @a dev.
*
* Increments usage counter by one. You should release the disk device
* descriptor with rtems_disk_release(). Returns @c NULL if no corresponding
* disk exists.
*/
rtems_disk_device *rtems_disk_obtain(dev_t dev);
/**
* Releases the disk device description @a dd.
*
* Decrements usage counter by one.
*/
rtems_status_code rtems_disk_release(rtems_disk_device *dd);
/**
* Disk device iterator.
*
* Returns the next disk device descriptor with a device identifier larger than
* @a dev. If there is no such device, @c NULL will be returned. Use minus
* one to start the search.
*
* @code
* rtems_disk_device *dd = rtems_disk_next((dev_t) -1);
*
* while (dd != NULL) {
* dd = rtems_disk_next(dd->dev);
* }
* @endcode
*/
rtems_disk_device *rtems_disk_next(dev_t dev);
/**
* Initializes the disk device management.
*
* This functions returns successful if the disk device management is already
* initialized. There is no protection against concurrent access.
*/
rtems_status_code rtems_disk_io_initialize(void);
/**
* Releases all resources allocated for disk device management.
*/
rtems_status_code rtems_disk_io_done(void);
/** @} */
#ifdef __cplusplus
}
#endif
#endif
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