msc_opts Struct Reference

Mass-storage configuration: a block-storage backend + presentation options. More...

#include <classes/msc.h>

Collaboration diagram for msc_opts:

Data Fields
uint32_t(*	num_blocks )(void *user)
	Report the medium's capacity, in blocks.
uint32_t(*	block_size )(void *user)
	Report the block size in bytes (commonly 512).
int(*	read )(void *user, uint32_t lba, uint32_t count, uint8_t *buf)
	Read count blocks starting at logical block lba.
int(*	write )(void *user, uint32_t lba, uint32_t count, const uint8_t *buf)
	Write count blocks starting at logical block lba.
int	n_luns
	Logical units this interface carries: entries used in luns.
msc_lun	luns [MSC_MAX_LUNS]
	The units, when n_luns says there are several.
int	read_only
	Present a write-protected medium (every unit)
int	medium
	What the medium is: one of MSC_MEDIUM_DISK (the default), MSC_MEDIUM_CDROM or MSC_MEDIUM_FLOPPY.
int	ufi
	Declare the UFI command set (bInterfaceSubClass 0x04, SFF-8070i) instead of SCSI transparent (0x06) - the subclass a real USB floppy drive reports, and what makes Windows show the drive as a floppy rather than a removable disk.
const char *	vendor
	INQUIRY strings (may be NULL).
const char *	product
const char *	revision
const char *	serial
	Serial number returned by INQUIRY EVPD page 0x80, which Windows asks every removable device for (may be NULL for a default).
void(*	on_command )(void *user, const char *text)
	Human-readable log hook, called with a description of each SCSI command handled (may be NULL).
const char *	name
	Optional iInterface name for this disk, e.g.
void *	user
	Opaque pointer passed to on_command - and, on a single-unit disk, to the block callbacks above.

Detailed Description

Mass-storage configuration: a block-storage backend + presentation options.

The backend addresses the medium in fixed-size blocks. With one logical unit - the default - every callback receives the opaque user pointer below; with several (see luns) they receive that unit's msc_lun::user instead, and user is left to on_command.

Field Documentation

num_blocks

uint32_t(* msc_opts::num_blocks) (void *user)

Report the medium's capacity, in blocks.

Parameters

user	the unit's backend context.

Returns

the number of addressable blocks (capacity = this × block_size()).

block_size

uint32_t(* msc_opts::block_size) (void *user)

Report the block size in bytes (commonly 512).

Parameters

user	the unit's backend context.

Returns

bytes per block.

read

int(* msc_opts::read) (void *user, uint32_t lba, uint32_t count, uint8_t *buf)

Read count blocks starting at logical block lba.

Parameters

user	the unit's backend context.
lba	first logical block address.
count	number of blocks to read.
buf	destination, count × block_size() bytes.

Returns

0 on success, non-zero to fail the SCSI command.

write

int(* msc_opts::write) (void *user, uint32_t lba, uint32_t count, const uint8_t *buf)

Write count blocks starting at logical block lba.

Parameters

user	the unit's backend context.
lba	first logical block address.
count	number of blocks to write.
buf	source, count × block_size() bytes.

Returns

0 on success, non-zero to fail the SCSI command.

n_luns

int msc_opts::n_luns

Logical units this interface carries: entries used in luns.

Zero - the usual case - means one unit, backed by user, described by the fields below; anything above MSC_MAX_LUNS is refused by msc_add().

luns

msc_lun msc_opts::luns[MSC_MAX_LUNS]

The units, when n_luns says there are several.

read_only

int msc_opts::read_only

Present a write-protected medium (every unit)

medium

int msc_opts::medium

What the medium is: one of MSC_MEDIUM_DISK (the default), MSC_MEDIUM_CDROM or MSC_MEDIUM_FLOPPY.

A CD-ROM is always read-only; a floppy answers MODE SENSE page 0x05 with the geometry of the standard format its capacity matches. Overridden per unit by msc_lun::medium

ufi

int msc_opts::ufi

Declare the UFI command set (bInterfaceSubClass 0x04, SFF-8070i) instead of SCSI transparent (0x06) - the subclass a real USB floppy drive reports, and what makes Windows show the drive as a floppy rather than a removable disk.

The transport stays Bulk-Only (bInterfaceProtocol 0x50); UFI-over-CBI is not offered. Intended for MSC_MEDIUM_FLOPPY, but not restricted to it. The UFI commands themselves (FORMAT UNIT, READ(12)/WRITE(12), VERIFY, SEEK, REZERO UNIT) are answered whatever the subclass, as they are legal SCSI too.

vendor

const char* msc_opts::vendor

INQUIRY strings (may be NULL).

The vendor and revision are the device's; the product id is overridden per unit by msc_lun::product.

product

const char * msc_opts::product

revision

const char * msc_opts::revision

serial

const char* msc_opts::serial

Serial number returned by INQUIRY EVPD page 0x80, which Windows asks every removable device for (may be NULL for a default).

Truncated past 20 chars. Overridden per unit by msc_lun::serial.

on_command

void(* msc_opts::on_command) (void *user, const char *text)

Human-readable log hook, called with a description of each SCSI command handled (may be NULL).

On a multi-unit disk each line names its unit.

Parameters

user	the user pointer.
text	a NUL-terminated description.

name

const char* msc_opts::name

Optional iInterface name for this disk, e.g.

"Storage" - shown by the host (Linux: /sys/bus/usb/devices/.../interface; Windows: the device name).

user

void* msc_opts::user

Opaque pointer passed to on_command - and, on a single-unit disk, to the block callbacks above.

With n_luns set, each unit brings its own msc_lun::user for those instead.

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The documentation for this struct was generated from the following file:

• classes/msc.h