Block Device Management

Modules
	Flash Disk Device
	Generic Disk Device
	RAM Disk Device
	Sparse Disk Device

Files
file	blkdev.h
	Block Device Management.
file	blkdev-blkstats.c
	Block Device Statistics Command.
file	blkdev-ioctl.c
	Common IO Control Primitive.
file	blkdev-ops.c
	Block device management.
file	blkdev-print-stats.c
	Prints the Block Device Statistics.
file	blkdev.c
	Block Device Management.

Data Structures
struct	rtems_blkdev_sg_buffer
	Block device scatter or gather buffer structure. More...
struct	rtems_blkdev_request
	The block device transfer request is used to read or write a number of blocks from or to the device. More...

Macros
#define	RTEMS_BLKDEV_START_BLOCK(req)   (req->bufs[0].block)
	The start block in a request.

Typedefs
typedef enum rtems_blkdev_request_op	rtems_blkdev_request_op
	Block device request type.
typedef void(*	rtems_blkdev_request_cb) (struct rtems_blkdev_request *req, rtems_status_code status)
	Block device request done callback function type.
typedef struct rtems_blkdev_sg_buffer	rtems_blkdev_sg_buffer
	Block device scatter or gather buffer structure.
typedef struct rtems_blkdev_request	rtems_blkdev_request
	The block device transfer request is used to read or write a number of blocks from or to the device.

Enumerations
enum	rtems_blkdev_request_op { RTEMS_BLKDEV_REQ_READ , RTEMS_BLKDEV_REQ_WRITE , RTEMS_BLKDEV_REQ_SYNC }
	Block device request type. More...

Functions
int	rtems_blkdev_ioctl (rtems_disk_device *dd, uint32_t req, void *argp)
	Common IO control primitive.
rtems_status_code	rtems_blkdev_create (const char *device, uint32_t media_block_size, rtems_blkdev_bnum media_block_count, rtems_block_device_ioctl handler, void *driver_data)
	Creates a block device.
rtems_status_code	rtems_blkdev_create_partition (const char *partition, const char *parent_block_device, rtems_blkdev_bnum media_block_begin, rtems_blkdev_bnum media_block_count)
	Creates a partition within a parent block device.
void	rtems_blkdev_print_stats (const rtems_blkdev_stats *stats, uint32_t media_block_size, uint32_t media_block_count, uint32_t block_size, const rtems_printer *printer)
	Prints the block device statistics.
void	rtems_blkstats (const rtems_printer *printer, const char *device, bool reset)
	Block device statistics command.

IO Control Request Codes
#define	RTEMS_BLKIO_REQUEST   _IOWR('B', 1, rtems_blkdev_request)
#define	RTEMS_BLKIO_GETMEDIABLKSIZE   _IOR('B', 2, uint32_t)
#define	RTEMS_BLKIO_GETBLKSIZE   _IOR('B', 3, uint32_t)
#define	RTEMS_BLKIO_SETBLKSIZE   _IOW('B', 4, uint32_t)
#define	RTEMS_BLKIO_GETSIZE   _IOR('B', 5, rtems_blkdev_bnum)
#define	RTEMS_BLKIO_SYNCDEV   _IO('B', 6)
#define	RTEMS_BLKIO_DELETED   _IO('B', 7)
#define	RTEMS_BLKIO_CAPABILITIES   _IO('B', 8)
#define	RTEMS_BLKIO_GETDISKDEV   _IOR('B', 9, rtems_disk_device *)
#define	RTEMS_BLKIO_PURGEDEV   _IO('B', 10)
#define	RTEMS_BLKIO_GETDEVSTATS   _IOR('B', 11, rtems_blkdev_stats *)
#define	RTEMS_BLKIO_RESETDEVSTATS   _IO('B', 12)

Block Device Driver Capabilities
#define	RTEMS_BLKDEV_CAP_MULTISECTOR_CONT   (1 << 0)
	Only consecutive multi-sector buffer requests are supported.
#define	RTEMS_BLKDEV_CAP_SYNC   (1 << 1)
	The driver will accept a sync call.

Detailed Description

Interface between device drivers and the block device buffer module.

The heart of the block device driver is the RTEMS_BLKIO_REQUEST IO control. This call puts IO requests to the block device for asynchronous processing. When a driver executes a request, it invokes the request done callback function to finish the request.

Macro Definition Documentation

RTEMS_BLKDEV_CAP_MULTISECTOR_CONT

#define RTEMS_BLKDEV_CAP_MULTISECTOR_CONT   (1 << 0)

Only consecutive multi-sector buffer requests are supported.

This option means the cache will only supply multiple buffers that are inorder so the ATA multi-sector command for example can be used. This is a hack to work around the current ATA driver.

RTEMS_BLKDEV_CAP_SYNC

#define RTEMS_BLKDEV_CAP_SYNC   (1 << 1)

The driver will accept a sync call.

A sync call is made to a driver after a bdbuf cache sync has finished.

RTEMS_BLKDEV_START_BLOCK

#define RTEMS_BLKDEV_START_BLOCK

(

req

)

(req->bufs[0].block)

The start block in a request.

Only valid if the driver has returned the RTEMS_BLKDEV_CAP_MULTISECTOR_CONT capability.

Typedef Documentation

rtems_blkdev_request

typedef struct rtems_blkdev_request rtems_blkdev_request

The block device transfer request is used to read or write a number of blocks from or to the device.

Transfer requests are issued to the disk device driver with the RTEMS_BLKIO_REQUEST IO control. The transfer request completion status must be signalled with rtems_blkdev_request_done(). This function must be called exactly once per request. The return value of the IO control will be ignored for transfer requests.

See also

rtems_blkdev_create().

rtems_blkdev_request_op

typedef enum rtems_blkdev_request_op rtems_blkdev_request_op

Block device request type.

Warning

The sync request is an IO one and only used from the cache. Use the Block IO when operating at the device level. We need a sync request to avoid requests looping for ever.

Enumeration Type Documentation

rtems_blkdev_request_op

enum rtems_blkdev_request_op

Block device request type.

Warning

The sync request is an IO one and only used from the cache. Use the Block IO when operating at the device level. We need a sync request to avoid requests looping for ever.

Enumerator
RTEMS_BLKDEV_REQ_READ	Read the requested blocks of data.
RTEMS_BLKDEV_REQ_WRITE	Write the requested blocks of data.
RTEMS_BLKDEV_REQ_SYNC	Sync any data with the media.

Function Documentation

rtems_blkdev_create()

rtems_status_code rtems_blkdev_create	(	const char *	device,
		uint32_t	media_block_size,
		rtems_blkdev_bnum	media_block_count,
		rtems_block_device_ioctl	handler,
		void *	driver_data
	)

Creates a block device.

The block size is set to the media block size.

Parameters

[in]	device	The path for the new block device.
[in]	media_block_size	The media block size in bytes. Must be positive.
[in]	media_block_count	The media block count. Must be positive.
[in]	handler	The block device IO control handler. Must not be NULL.
[in]	driver_data	The block device driver data.

Return values

RTEMS_SUCCESSFUL	Successful operation.
RTEMS_INVALID_NUMBER	Media block size or count is not positive.
RTEMS_NO_MEMORY	Not enough memory.
RTEMS_UNSATISFIED	Cannot create generic device node.
RTEMS_INCORRECT_STATE	Cannot initialize bdbuf.

See also

rtems_blkdev_create_partition(), rtems_bdbuf_set_block_size(), and rtems_blkdev_request.

rtems_blkdev_create_partition()

rtems_status_code rtems_blkdev_create_partition	(	const char *	partition,
		const char *	parent_block_device,
		rtems_blkdev_bnum	media_block_begin,
		rtems_blkdev_bnum	media_block_count
	)

Creates a partition within a parent block device.

A partition manages a subset of consecutive blocks contained in a parent block device. The blocks must be within the range of blocks managed by the associated parent block device. The media block size and IO control handler are inherited by the parent block device. The block size is set to the media block size.

Parameters

[in]	partition	The path for the new partition device.
[in]	parent_block_device	The parent block device path.
[in]	media_block_begin	The media block begin of the partition within the parent block device.
[in]	media_block_count	The media block count of the partition.

Return values

RTEMS_SUCCESSFUL	Successful operation.
RTEMS_INVALID_ID	Block device node does not exist.
RTEMS_INVALID_NODE	File system node is not a block device.
RTEMS_NOT_IMPLEMENTED	Block device implementation is incomplete.
RTEMS_INVALID_NUMBER	Block begin or block count is invalid.
RTEMS_NO_MEMORY	Not enough memory.
RTEMS_UNSATISFIED	Cannot create generic device node.

See also

rtems_blkdev_create() and rtems_bdbuf_set_block_size().

rtems_blkdev_ioctl()

int rtems_blkdev_ioctl	(	rtems_disk_device *	dd,
		uint32_t	req,
		void *	argp
	)

Common IO control primitive.

Use this in all block devices to handle the common set of IO control requests.