Intro(9E)
NAME
Intro, intro − introduction to device driver entry points
DESCRIPTION
Section 9E describes the entry-point routines a developer may include in a device driver. These are called entry-point because they provide the calling and return syntax from the kernel into the driver. Entry-points are called, for instance, in response to system calls, when the driver is loaded, or in response to STREAMS events.
Kernel functions usable by the driver are described in section 9F.
In this section, reference pages contain the following headings:
• NAME describes the routine’s purpose.
• SYNOPSIS summarizes the routine’s calling and return syntax.
• INTERFACE LEVEL describes any architecture dependencies. It also indicates whether the use of the entry point is required, optional, or discouraged.
• ARGUMENTS describes each of the routine’s arguments.
• DESCRIPTION provides general information about the routine.
• RETURN VALUES describes each of the routine’s return values.
• SEE ALSO gives sources for further information.
Overview of Driver Entry-Point Routines and Naming Conventions
By convention, a prefix string is added to the driver routine names. For a driver with the prefix prefix, the driver code may contain routines named prefixopen, prefixclose, prefixread, prefixwrite, and so forth. All global variables associated with the driver should also use the same prefix.
All routines and data should be declared as static.
Every driver MUST include <sys/ddi.h> and <sys/sunddi.h>, in that order, and after all other include files.
The following table summarizes the STREAMS driver entry points described in this section.
| Routine | Type |
| put | DDI/DKI |
| srv | DDI/DKI |
The following table summarizes the driver entry points described in this section.
| Routine | Type |
| _fini | Solaris DDI |
| _info | Solaris DDI |
| _init | Solaris DDI |
| aread | Solaris DDI |
| attach | Solaris DDI |
| awrite | Solaris DDI |
| chpoll | DDI/DKI |
| close | DDI/DKI |
| detach | Solaris DDI |
| devmap | Solaris DDI |
| devmap_access | Solaris DDI |
| devmap_contextmgt | Solaris DDI |
| devmap_dup | Solaris DDI |
| devmap_map | Solaris DDI |
| devmap_unmap | Solaris DDI |
| dump | Solaris DDI |
| getinfo | Solaris DDI |
| identify | Solaris DDI |
| ioctl | DDI/DKI |
| ks_update | Solaris DDI |
| mapdev_access | Solaris DDI |
| mapdev_dup | Solaris DDI |
| mapdev_free | Solaris DDI |
| mmap | DKI only |
| open | DDI/DKI |
| power | Solaris DDI |
| DDI/DKI | |
| probe | Solaris DDI |
| prop_op | Solaris DDI |
| read | DDI/DKI |
| segmap | DKI only |
| strategy | DDI/DKI |
| tran_abort | Solaris DDI |
| tran_destroy_pkt | Solaris DDI |
| tran_dmafree | Solaris DDI |
| tran_getcap | Solaris DDI |
| tran_init_pkt | Solaris DDI |
| tran_reset | Solaris DDI |
| tran_reset_notify | Solaris DDI |
| tran_setcap | Solaris DDI |
| tran_start | Solaris DDI |
| tran_sync_pkt | Solaris DDI |
| tran_tgt_free | Solaris DDI |
| tran_tgt_init | Solaris DDI |
| tran_tgt_probe | Solaris DDI |
| write | DDI/DKI |
The following table lists the error codes returned by a driver routine when it encounters an error. The error values are listed in alphabetic order and are defined in <sys/errno.h>. In the driver open(9E), close(9E), ioctl(9E), read(9E), and write(9E) routines, errors are passed back to the user by returning the value. In the driver strategy(9E) routine, errors are passed back to the user by setting the b_error member of the buf(9S) structure to the error code. For STREAMS ioctl routines, errors should be sent upstream in an M_IOCNAK message. For STREAMS read and write routines, errors should be sent upstream in an M_ERROR message. The driver print routine should not return an error code because the function that it calls, cmn_err(9F), is declared as void (no error is returned).
| Error | Use in these | |
| Value | Error Description | Driver Routines (9E) |
| EAGAIN | Kernel resources, such as the buf structure or cache memory, are not available at this time (device may be busy, or the system resource is not available). | open, ioctl, read, write, strategy |
| EFAULT | An invalid address has been passed as an argument; memory addressing error. | open, close, ioctl, read, write, strategy |
| EINTR | Sleep interrupted by signal. | open, close, ioctl, read, write, strategy |
| EINVAL | An invalid argument was passed to the routine. | open, ioctl, read, write, strategy |
| EIO | A device error occurred; an error condition was detected in a device status register (the I/O request was valid, but an error occurred on the device). | open, close, ioctl, read, write, strategy |
| ENXIO | An attempt was made to access a device or subdevice that does not exist (one that is not configured); an attempt was made to perform an invalid I/O operation; an incorrect minor number was specified. | open, close, ioctl, read, write, strategy |
| EPERM | A process attempting an operation did not have required permission. | open, ioctl, read, write, close |
| EROFS | An attempt was made to open for writing a read-only device. | open |
The table below cross references error values to the driver routines from which the error values can be returned.
| read, write, | |||
| open | close | ioctl | and strategy |
| EAGAIN | EFAULT | EAGAIN | EAGAIN |
| EFAULT | EINTR | EFAULT | EFAULT |
| EINTR | EIO | EINTR | EINTR |
| EINVAL | ENXIO | EINVAL | EINVAL |
| EIO | EIO | EIO | |
| ENXIO | ENXIO | ENXIO | |
| EPERM | EPERM | ||
| EROFS |
LIST OF ENTRY POINTS
Name Description
aread(9E) asynchronous read from a device
attach(9E) attach a device to the system, or resume it
awrite(9E) asynchronous write to a device
chpoll(9E) poll entry point for a non-STREAMS character driver
close(9E) relinquish access to a device
csx_event_handler(9E) PC Card driver event handler
detach(9E) detach a device
devmap(9E) validate and translate virtual mapping for memory mapped device
devmap_access(9E) device mapping access entry point
devmap_contextmgt(9E) driver callback function for context management
devmap_dup(9E) device mapping duplication entry point
devmap_map(9E) device mapping create entry point
devmap_unmap(9E) device mapping unmap entry point
dump(9E) dump memory to device during system failure
_fini(9E) loadable module configuration entry points
getinfo(9E) get device driver information
identify(9E) determine if a driver is associated with a device
_info(9E) See _fini(9E)
_init(9E) See _fini(9E)
ioctl(9E) control a character device
ks_update(9E) dynamically update kstats
mapdev_access(9E) device mapping access entry point
mapdev_dup(9E) device mapping duplication entry point
mapdev_free(9E) device mapping free entry point
mmap(9E) check virtual mapping for memory mapped device
open(9E) gain access to a device
pm(9E) power management properties
power(9E) power a device attached to the system
print(9E) display a driver message on system console
probe(9E) determine if a non-self-identifying device is present
prop_op(9E) report driver property information
put(9E) receive messages from the preceding queue
read(9E) read data from a device
segmap(9E) map device memory into user space
srv(9E) service queued messages
strategy(9E) perform block I/O
tran_abort(9E) abort a SCSI command
tran_destroy_pkt(9E) See tran_init_pkt(9E)
tran_dmafree(9E) SCSI HBA DMA deallocation entry point
tran_getcap(9E) get/set SCSI transport capability
tran_init_pkt(9E) SCSI HBA packet preparation and deallocation
tran_reset(9E) reset a SCSI bus or target
tran_reset_notify(9E) request to notify SCSI target of bus reset
tran_setcap(9E) See tran_getcap(9E)
tran_start(9E) request to transport a SCSI command
tran_sync_pkt(9E) SCSI HBA memory synchronization entry point
tran_tgt_free(9E) request to free HBA resources allocated on behalf of a target
tran_tgt_init(9E) request to initialize HBA resources on behalf of a particular target
tran_tgt_probe(9E) request to probe SCSI bus for a particular target
write(9E) write data to a device
SunOS 5.6 — Last change: 22 Jan 1997