mdevice(F)

Format

Description

See the section ``Specifying STREAMS modules and devices'' for details of how to specify STREAMS device drivers and line discipline modules.

Each line of mdevice contains nine fields (xnamexdma). Each field must contain an entry. The entry for fields funcs and chars may be dash (-) if no value is being supplied. Fields must be separated by spaces or tabs. The fields are described below:

xnamex

Device name: The internal name of the device or module; this may be up to 8 characters long. The first character of the name must be an alphabetic character; the others may be letters, digits, or underscores. When created using configure, this field defaults to being the same as the handler prefix (prefix) unless overridden using the -h option.

funcs

Function list: A string of characters that identifies the driver functions that are present. Using one of the characters below requires the driver to have an entry point (function) of the type indicated. When the kernel is relinked an entry is made in the kernel switch tables for each function in the list. If no functions in the following list are supplied, the field should contain a dash. Most drivers use some or all of the following functions:

c

close function. Called whenever the last open connection to a device node associated with this driver is closed.

i

ioctl function. I/O control function called to issue control commands to the driver. Used by character devices only.

I

init function. Called by the system during the system boot sequence to initialize the driver or module for use. Interrupts are not enabled when this function is called.

o

open function. Called whenever a device node associated with this driver is opened.

r

read function. Called to read data from a device controlled by this driver. Used by character devices only.

R

probe function. Called by the system to determine the devices present.

w

write function. Called to write data to a device controlled by this driver. Used by character devices only.

The remaining functions in this list are likely to be used only by drivers with special requirements:

e

exec function. Called when a process with an open (or previously open) connection to this device, using this driver, issues an exec system call. Provided for devices which must perform specific actions when this situation arises.

E

kenter function. Called by the system whenever kernel mode is entered. Provided for drivers which have specific actions to carry out whenever this happens.

h

halt function. Called during system shutdown. This might be provided if, for instance, the driver needs to reset hardware in preparation for a warm boot.

p

poll function. Called once every system clock-tick. This might be required (for instance) for a device which loses interrupts and needs to be re-primed periodically.

P

pminit function. Pre-main initialization function called by the system very early in the system initialization process. Provided for drivers which need to be initialized early. Normally this function is used by a kernel debugger so that it is available to the user as early as possible.

s

start function. Secondary initialization function called by the system late in the system boot sequence. Provided for drivers which have initialization functions which must be deferred until after system interrupts have been enabled.

S

swtch function. Called by the system whenever a process context switch occurs. This is provided for drivers which have specific actions to carry out whenever a context switch occurs.

x

exit function. Called when a process with a previously open connection to this device exits. Provided for devices which must perform specific actions when this situation arises.

X

kexit function. Called on exit from kernel mode to user mode. Provided for drivers which have specific actions to carry out when this happens.

No characters are used to represent the strategy and print routines of a ``block'' type device driver (see field chars below). Such a driver must include these routines in any case.

chars

Characteristics of driver: A set of characters that indicates the characteristics of the driver. If none of the characters below apply, the field should contain a dash. The legal characters for this field are:

a

The driver is installed automatically.

b

The device is a ``block'' device.

B

The driver should be present in a generic boot kernel that is built using the command mkdev fd.

c

The device is a ``character'' device.

C

The device is a scatter/gather device which performs cluster I/O requests. (Block devices only.)

d

Indicates that a device can perform DMA transfers to any address in physical memory, or does not require DMA at all. If this characteristic is not set, the device needs cache buffers below 16MB. Setting this for devices which do not use DMA may prevent unnecessary use of low buffers.

D

This option indicates that the device driver can share its DMA channel.

G

The interrupt handler specified in the sdevice(F) entry is not installed, but is checked for conflicts with other devices. This is used when you wish to associate a device with a specific device group.

h

The device is a SCSI host adapter.

H

This device driver controls hardware. This option distinguishes drivers that support hardware from those that are entirely software (pseudo-devices).

i

The device driver is installable.

I

Ignore pack.d directory. This option prevents the system from looking for driver components when relinking the kernel. This option is used when the functions associated with this driver name are actually included in another driver.

k

Instruct idmknod to leave device nodes (special files) of the same type (``character'' or ``block'') and with the same major number as this device in the /dev directory, even if the device is configured out of the kernel.

M

This driver defines a range of extended minor device numbers for a driver already defined in a preceding entry. This also causes the Minimum and Maximum fields to be interpreted differently. (See fields minu and maxu below.)

n

The driver is not installable.

N

No Driver.o or space.c file.

o

This device may have only one sdevice(F) entry.

O

This option indicates that the IOA range (sdevice(F) columns 7 and 8) of this device may overlap that of another device, which must also have the 'O' characteristic.

p

The device is a SCSI peripheral.

Q

The device is a console driver.

r

This device is required in all configurations of the kernel. This option is intended for drivers delivered with the base system only. Device nodes (special files in the /dev directory), once made for this device, are never removed. See idmknod(ADM).

R

This device has a device information file (device.dat).

s

Suppress device count field.

S

This device driver is a STREAMS module.

t

The device is a ttym and has a _tty table.

v

This device driver uses the Generic Platform Interface (GPI) and is supported by an SMP vendor.

x

The x setting no longer has any effect in the ``chars'' field. It is included for backward compatability.

Z

This driver may have multiple entries in the mdevice file, with different major numbers.

prefix

Handler prefix: A character string used as a prefix for all the externally-known handler routines associated with this driver. The string may be up to 4 characters long.

bmajor

Block major device number: This is set to zero in a DSP Master file. If the device is a ``block'' type device, a value is assigned by idinstall during installation.

cmajor

Character major device number: This is set to zero in a DSP Master file. If the device is a ``character'' type device (or STREAMS type), a value is assigned by idinstall during installation.

minu

Minimum units: An integer specifying the minimum number of devices that can be attached to the controller. The actual number is specified in the sdevice(F) file. If ``M'' appears in the characteristics field chars, the value in this field is the base major number of the driver to which the extended minor numbers apply (BASE major).

maxu

Maximum units: An integer specifying the maximum number of devices that can be attached to the controller. The actual number is specified in the sdevice file. If ``M'' appears in the characteristics field chars, the value in this field is the offset at which the range of the extended minor numbers begin (OFFSET) and must be a multiple of 256.

dma

DMA channel: An integer that specifies the DMA channel to be used by this device. If the device does not use DMA, place a ``-1'' in this field. Note that more than one device can share a DMA channel provided that each sharing device sets the ``D'' characteristic in field chars.

Specifying STREAMS modules and devices

A STREAMS module that is not a device driver, such as a line discipline module, requires an ``S'' in the characteristics field of its mdevice file entry, but should not include a ``c''.

Files

/etc/conf/cf.d

directory containing configuration files for linking the kernel

/etc/conf/cf.d/mdevice

description for all device driver modules

/etc/conf/cf.d/sdevice

specific characteristics for all devices

/etc/conf/sdevice.d/device

specific characteristics for device

/etc/conf/pack.d/device/Driver.o

device driver object module for device

/etc/conf/pack.d/device/device.dat

device information file

See also