intro(D2I) intro(D2I)
NAME
intro - introduction to PDI Driver Entry Point Routines
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
DESCRIPTION
This section describes the routines a developer needs to
include in a Portable Device Interface (PDI) driver.
USAGE
The routines described in this section are called ``entry
point routines'' because they provide the interfaces that the
kernel needs from PDI drivers. The kernel calls these
routines when needed. Some are called at well-defined times,
such as system start up. Others are called as a result of
I/O-related system calls or external events, such as
interrupts from peripheral devices.
Each PDI driver is organized into two logical parts: the base
level and the interrupt level. The base level interacts with
the kernel and the device on behalf of processes performing
I/O operations. The interrupt level interacts with the device
and the kernel as a result of an event such as data arrival,
and usually cannot be associated with any particular process.
Each PDI driver is uniquely identified by a prefix string
specified in its configuration file. The name of all the
driver-supplied routines and global variables should begin
with this prefix. This will reduce the chance of a symbol
collision with another driver or module. Any private routines
defined by a driver or module that are not entry point
routines should be declared as static. Also, any global
variables that are private to the driver or module should be
declared as static.
In general, any number of instances of the same driver entry
point routine can be running concurrently. It is the
responsibility of the driver to synchronize access to its
private data structures.
NOTICES
Applicability
sdi: 1, 2
Copyright 1994 Novell, Inc. Page 1