MSC - Mass storage (SCSI/BOT)

Collaboration diagram for MSC - Mass storage (SCSI/BOT):

Files
file	msc.h
	USB Mass Storage (Bulk-Only Transport + SCSI) device class, app API.

Data Structures
struct	msc_disk
	One mass-storage function: a single instance of the class on a device. More...
struct	msc_lun
	One logical unit: a backend context, plus what this unit alone presents itself as. More...
struct	msc_opts
	Mass-storage configuration: a block-storage backend + presentation options. More...

Macros
#define	MSC_MAX_LUNS
	Most logical units one mass-storage interface can carry.

Functions
msc_disk *	msc_add (usbip_device *dev, const msc_opts *opts)
	Add a mass-storage function to a device: one interface carrying one logical unit, or msc_opts::n_luns of them.
uint64_t	msc_floppy_format_size (int format)
	Byte size of a standard floppy format, for sizing the backing image.

Variables
const usbip_device_class	usbip_device_msc
	The mass-storage class, for usbip_device_add_class()

Medium type
What the disk presents itself as, set in msc_opts::medium. The default (0) is a plain removable disk, so a zero-initialised msc_opts needs no medium field.
#define	MSC_MEDIUM_DISK
	Removable direct-access disk (SCSI type 0x00)
#define	MSC_MEDIUM_CDROM
	Read-only CD-ROM (SCSI type 0x05), MMC commands answered.
#define	MSC_MEDIUM_FLOPPY
	Floppy: direct-access with a Flexible Disk geometry page.

Floppy format
The standard formats a MSC_MEDIUM_FLOPPY disk can be, passed to msc_floppy_format_size(). All of them are 512 bytes per sector.
#define	MSC_FLOPPY_2_88M
	2.88 MB - 80 cylinders, 2 heads, 36 sectors
#define	MSC_FLOPPY_1_44M
	1.44 MB - 80 cylinders, 2 heads, 18 sectors
#define	MSC_FLOPPY_1_2M
	1.2 MB - 80 cylinders, 2 heads, 15 sectors
#define	MSC_FLOPPY_720K
	720 KB - 80 cylinders, 2 heads, 9 sectors
#define	MSC_FLOPPY_360K
	360 KB - 40 cylinders, 2 heads, 9 sectors

Detailed Description

Macro Definition Documentation

MSC_MAX_LUNS

#define MSC_MAX_LUNS

Most logical units one mass-storage interface can carry.

The Bulk-Only Transport addresses a unit with the four-bit bCBWLUN field of the CBW, so sixteen is the transport's own ceiling, not a chosen one.

MSC_MEDIUM_DISK

#define MSC_MEDIUM_DISK

Removable direct-access disk (SCSI type 0x00)

MSC_MEDIUM_CDROM

#define MSC_MEDIUM_CDROM

Read-only CD-ROM (SCSI type 0x05), MMC commands answered.

MSC_MEDIUM_FLOPPY

#define MSC_MEDIUM_FLOPPY

Floppy: direct-access with a Flexible Disk geometry page.

MSC_FLOPPY_2_88M

#define MSC_FLOPPY_2_88M

2.88 MB - 80 cylinders, 2 heads, 36 sectors

MSC_FLOPPY_1_44M

#define MSC_FLOPPY_1_44M

1.44 MB - 80 cylinders, 2 heads, 18 sectors

MSC_FLOPPY_1_2M

#define MSC_FLOPPY_1_2M

1.2 MB - 80 cylinders, 2 heads, 15 sectors

MSC_FLOPPY_720K

#define MSC_FLOPPY_720K

720 KB - 80 cylinders, 2 heads, 9 sectors

MSC_FLOPPY_360K

#define MSC_FLOPPY_360K

360 KB - 40 cylinders, 2 heads, 9 sectors

Function Documentation

msc_add()

msc_disk * msc_add	(	usbip_device *	dev,
		const msc_opts *	opts
	)

Add a mass-storage function to a device: one interface carrying one logical unit, or msc_opts::n_luns of them.

Parameters

dev	the device.
opts	the block-storage backend and presentation options (see msc_opts).

Returns

the disk handle, or NULL on error.

msc_floppy_format_size()

uint64_t msc_floppy_format_size

(

int

format

)

Byte size of a standard floppy format, for sizing the backing image.

A MSC_MEDIUM_FLOPPY disk takes its geometry from the capacity it is given, so an app that wants a real floppy sizes its image with this. A capacity matching none of the formats still works - the class reports the true block count with 1.44M's head/sector layout - but no host will call it a standard floppy.

Parameters

format

one of the MSC_FLOPPY_* codes.

Returns

the size in bytes, or 0 if format is not one of them.

Variable Documentation

usbip_device_msc

const usbip_device_class usbip_device_msc

extern

The mass-storage class, for usbip_device_add_class()