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;; Copyright (C) KolibriOS team 2011-2012. All rights reserved. ;;

;; Distributed under terms of the GNU General Public License    ;;

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$Revision: 2643 $

; =============================================================================

; ================================= Constants =================================

; =============================================================================

; Error codes for callback functions.

DISK_STATUS_OK              = 0 ; success

DISK_STATUS_GENERAL_ERROR   = -1; if no other code is suitable

DISK_STATUS_INVALID_CALL    = 1 ; invalid input parameters

DISK_STATUS_NO_MEDIA        = 2 ; no media present

DISK_STATUS_END_OF_MEDIA    = 3 ; end of media while reading/writing data

; Driver flags. Represent bits in DISK.DriverFlags.

DISK_NO_INSERT_NOTIFICATION = 1

; Media flags. Represent bits in DISKMEDIAINFO.Flags.

DISK_MEDIA_READONLY = 1

; If too many partitions are detected,there is probably an error on the disk.

; 256 partitions should be enough for any reasonable use.

; Also, the same number is limiting the number of MBRs to process; if

; too many MBRs are visible,there probably is a loop in the MBR structure.

MAX_NUM_PARTITIONS = 256

; =============================================================================

; ================================ Structures =================================

; =============================================================================

; This structure defines all callback functions for working with the physical

; device. They are implemented by a driver. Objects with this structure reside

; in a driver.

struct  DISKFUNC

        strucsize       dd ?

; Size of the structure. This field is intended for possible extensions of

; this structure. If a new function is added to this structure and a driver

; implements an old version, the caller can detect this by checking .strucsize,

; so the driver remains compatible.

        close           dd ?

; The pointer to the function which frees all driver-specific resources for

; the disk.

; Optional, may be NULL.

; void close(void* userdata);

        closemedia      dd ?

; The pointer to the function which informs the driver that the kernel has

; finished all processing with the current media. If media is removed, the

; driver should decline all requests to that media with DISK_STATUS_NO_MEDIA,

; even if new media is inserted, until this function is called. If media is

; removed, a new call to 'disk_media_changed' is not allowed until this

; function is called.

; Optional, may be NULL (if media is not removable).

; void closemedia(void* userdata);

        querymedia      dd ?

; The pointer to the function which determines capabilities of the media.

; int querymedia(void* userdata, DISKMEDIAINFO* info);

; Return value: one of DISK_STATUS_*

        read            dd ?

; The pointer to the function which reads data from the device.

; int read(void* userdata, void* buffer, __int64 startsector, int* numsectors);

; input: *numsectors = number of sectors to read

; output: *numsectors = number of sectors which were successfully read

; Return value: one of DISK_STATUS_*

        write           dd ?

; The pointer to the function which writes data to the device.

; Optional, may be NULL.

; int write(void* userdata, void* buffer, __int64 startsector, int* numsectors);

; input: *numsectors = number of sectors to write

; output: *numsectors = number of sectors which were successfully written

; Return value: one of DISK_STATUS_*

        flush           dd ?

; The pointer to the function which flushes the internal device cache.

; Optional, may be NULL.

; int flush(void* userdata);

; Return value: one of DISK_STATUS_*

; Note that read/write are called by the cache manager, so a driver should not

; create a software cache. This function is implemented for flushing a hardware

; cache, if it exists.

        adjust_cache_size       dd ?

; The pointer to the function which returns the cache size for this device.

; Optional, may be NULL.

; unsigned int adjust_cache_size(unsigned int suggested_size);

; Return value: 0 = disable cache, otherwise = used cache size in bytes.

ends

; This structure holds information on a medium.

; Objects with this structure are allocated by the kernel as a part of the DISK

; structure and are filled by a driver in the 'querymedia' callback.

struct  DISKMEDIAINFO

        Flags           dd ?

; Combination of DISK_MEDIA_* bits.

        SectorSize      dd ?

; Size of the sector.

        Capacity        dq ?

; Size of the media in sectors.

ends

; This structure represents the disk cache. To follow the old implementation,

; there are two distinct caches for a disk, one for "system" data,and the other

; for "application" data.

struct  DISKCACHE

        mutex           MUTEX

; Lock to protect the cache.

; The following fields are inherited from data32.inc:cache_ideX.

        pointer         dd ?

        data_size       dd ?    ; unused

        data            dd ?

        sad_size        dd ?

        search_start    dd ?

ends

; This structure represents a disk device and its media for the kernel.

; This structure is allocated by the kernel in the 'disk_add' function,

; freed in the 'disk_dereference' function.

struct  DISK

; Fields of disk object

        Next            dd ?

        Prev            dd ?

; All disk devices are linked in one list with these two fields.

; Head of the list is the 'disk_list' variable.

        Functions       dd ?

; Pointer to the 'DISKFUNC' structure with driver functions.

        Name            dd ?

; Pointer to the string used for accesses through the global filesystem.

        UserData        dd ?

; This field is passed to all callback functions so a driver can decide which

; physical device is addressed.

        DriverFlags     dd ?

; Bitfield. Currently only DISK_NO_INSERT_NOTIFICATION bit is defined.

; If it is set, the driver will never issue 'disk_media_changed' notification

; with argument set to true, so the kernel must try to detect media during

; requests from the file system.

        RefCount        dd ?

; Count of active references to this structure. One reference is kept during

; the lifetime of the structure between 'disk_add' and 'disk_del'.

; Another reference is taken during any filesystem operation for this disk.

; One reference is added if media is inserted.

; The structure is destroyed when the reference count decrements to zero:

; this usually occurs in 'disk_del', but can be delayed to the end of last

; filesystem operation, if one is active.

        MediaLock       MUTEX

; Lock to protect the MEDIA structure. See the description after

; 'disk_list_mutex' for the locking strategy.

; Fields of media object

        MediaInserted   db ?

; 0 if media is not inserted, nonzero otherwise.

        MediaUsed       db ?

; 0 if media fields are not used, nonzero otherwise. If .MediaRefCount is

; nonzero, this field is nonzero too; however, when .MediaRefCount goes

; to zero, there is some time interval during which media object is still used.

        align 4

; The following fields are not valid unless either .MediaInserted is nonzero

; or they are accessed from a code which has obtained the reference when

; .MediaInserted was nonzero.

        MediaRefCount   dd ?

; Count of active references to the media object. One reference is kept during

; the lifetime of the media between two calls to 'disk_media_changed'.

; Another reference is taken during any filesystem operation for this media.

; The callback 'closemedia' is called when the reference count decrements to

; zero: this usually occurs in 'disk_media_changed', but can be delayed to the

; end of the last filesystem operation, if one is active.

        MediaInfo       DISKMEDIAINFO

; This field keeps information on the current media.

        NumPartitions   dd ?

; Number of partitions on this media.

        Partitions      dd ?

; Pointer to array of .NumPartitions pointers to PARTITION structures.

        cache_size      dd ?

; inherited from cache_ideX_size

        SysCache        DISKCACHE

        AppCache        DISKCACHE

; Two caches for the disk.

ends

; This structure represents one partition for the kernel. This is a base

; template, the actual contents after common fields is determined by the

; file system code for this partition.

struct  PARTITION

        FirstSector     dq ?

; First sector of the partition.

        Length          dq ?

; Length of the partition in sectors.

        Disk            dd ?

; Pointer to parent DISK structure.

        FSUserFunctions dd ?

; Handlers for the sysfunction 70h. This field is a pointer to the following

; array. The first dword is a number of supported subfunctions, other dwords

; point to handlers of corresponding subfunctions.

; This field is 0 if file system is not recognized.

; ...fs-specific data may follow...

ends

; This is an external structure, it represents an entry in the partition table.