.\" Copyright (c) 20002 Sun Microsystems, Inc. .\" All Rights Reserved. .\" Copyright 2018, Joyent, Inc. .\" The contents of this file are subject to the terms of the .\" Common Development and Distribution License (the "License"). .\" You may not use this file except in compliance with the License. .\" .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE .\" or http://www.opensolaris.org/os/licensing. .\" See the License for the specific language governing permissions .\" and limitations under the License. .\" .\" When distributing Covered Code, include this CDDL HEADER in each .\" file and include the License file at usr/src/OPENSOLARIS.LICENSE. .\" If applicable, add the following below this CDDL HEADER, with the .\" fields enclosed by brackets "[]" replaced with your own identifying .\" information: Portions Copyright [yyyy] [name of copyright owner] .Dd August 31, 2018 .Dt PRNIO 4I .Os .Sh NAME .Nm prnio .Nd generic printer interface .Sh SYNOPSIS .In sys/prnio.h .Sh DESCRIPTION The .Nm generic printer interface defines ioctl commands and data structures for printer device drivers. .Pp .Nm defines and provides facilities for five basic phases of the printing process: .Bl -bullet -offset indent .It Identification \(em Retrieve device information/attributes .It Setup \(em Set device attributes .It Transfer \(em Transfer data to or from the device .It Cleanup \(em Transfer phase conclusion .It Abort \(em Transfer phase interruption .El .Pp During the Identification phase, the application retrieves a set of device capabilities and additional information using the .Dv PRNIOC_GET_IFCAP , .Dv PRNIOC_GET_STATUS , .Dv PRNIOC_GET_TIMEOUTS , .Dv PRNIOC_GET_IFINFO , and .Dv PRNIOC_GET_1284_DEVID commands. .Pp During the Setup phase the application sets some interface attributes and probably resets the printer as described in the .Dv PRNIOC_SET_IFCAP , .Dv PRNIOC_SET_TIMEOUTS , and .Dv PRNIOC_RESET sections. .Pp During the Transfer phase, data is transferred in a forward (host to peripheral) or reverse direction (peripheral to host). Transfer is accomplished using .Xr write 2 and .Xr read 2 system calls. For .Nm compliant printer drivers, forward transfer support is mandatory, while reverse transfer support is optional. Applications can also use .Dv PRNIOC_GET_STATUS and .Dv PRNIOC_GET_1284_STATUS commands during the transfer to monitor the device state. .Pp The Cleanup phase is accomplished by closing the device using .Xr close 2 . Device drivers supporting .Nm may set non-zero error code as appropriate. Applications should explicitly .Xr close 2 a device before exiting and check .Va errno value. .Pp The Abort phase is accomplished by interrupting the .Xr write 2 and .Xr read 2 system calls. The application can perform some additional cleanup during the Abort phase as described in .Dv PRNIOC_GET_IFCAP section. .Sh IOCTLS .Bl -tag -width PRNIOC_GET_IFINFO .It Dv PRNIOC_GET_IFCAP Application can retrieve printer interface capabilities using this command. The .Xr ioctl 2 argument is a pointer to .Vt uint_t , a bit field representing a set of properties and services provided by a printer driver. Set bit means supported capability. The following values are defined: .Bl -tag -width PRN_1284_STATUS .It Dv PRN_BIDI When this bit is set, the interface operates in a bidirectional mode, instead of forward-only mode. .It Dv PRN_HOTPLUG If this bit is set, the interface allows device hot-plugging. .It Dv PRN_1284_DEVID If this bit is set, the device is capable of returning .Em 1284 device ID (see .Dv PRNIOC_GET_1284_DEVID ) . .It Dv PRN_1284_STATUS If this bit is set, the device driver can return device status lines (see .Dv PRNIOC_GET_1284_STATUS ) . Some devices support this ioctl in unidirectional mode only. .It Dv PRN_TIMEOUTS If this bit is set the peripheral may stall during the transfer phase and the driver can timeout and return from the .Xr write 2 and .Xr read 2 returning the number of bytes that have been transferred. If .Dv PRN_TIMEOUTS is set, the driver supports this functionality and the timeout values can be retrieved and modified via the .Dv PRNIOC_GET_TIMEOUTS and .Dv PRNIOC_SET_TIMEOUTS ioctls. Otherwise, applications can implement their own timeouts and abort phase. .It Dv PRN_STREAMS This bit impacts the application abort phase behaviour. If the device claimed .Dv PRN_STREAMS capability, the application must issue an .Dv I_FLUSH .Xr ioctl 2 before .Xr close 2 to dismiss the untransferred data. Only STREAMS drivers can support this capability. .El .It Dv PRNIOC_SET_IFCAP This ioctl can be used to change interface capabilities. The argument is a pointer to .Vt uint_t bit field that is described in detail in the .Dv PRNIOC_GET_IFCAP section. Capabilities should be set one at a time; otherwise the command will return .Er EINVAL . The following capabilities can be changed by this ioctl: .Bl -tag -width PRN_BIDI .It Dv PRN_BIDI When this capability is set, the interface operates in a bidirectional mode, instead of forward-only mode. Devices that support only one mode will not return error; applications should use .Dv PRNIOC_GET_IFCAP to check if the mode was successfully changed. Because some capabilities may be altered as a side effect of changing other capabilities, this command should be followed by .Dv PRNIOC_GET_IFCAP . .El .It Dv PRNIOC_GET_IFINFO This command can be used to retrieve printer interface info string, which is an arbitrary format string usually describing the bus type. The argument is a pointer to .Vt struct prn_interface_info as described below. .Bd -literal -offset 2n struct prn_interface_info { uint_t if_len; /* length of buffer */ uint_t if_rlen; /* actual info length */ char *if_data; /* buffer address */ }; .Ed .Pp The application allocates a buffer and sets .Fa if_data and .Fa if_len values to its address and length, respectively. The driver returns the string to this buffer and sets .Fa if_len to its length. If .Fa if_len is less than .Fa if_rlen , the driver must return the first .Fa if_len bytes of the string. The application may then repeat the command with a bigger buffer. .Pp Although .Nm does not limit the contents of the interface info string, some values are recommended and defined in .In sys/prnio.h by the following macros: .Pp .Bl -tag -width PRN_PARALLEL -compact .It Dv PRN_PARALLEL Centronics or .Em IEEE 1284 compatible devices .It Dv PRN_SERIAL EIA-232/EIA-485 serial ports .It Dv PRN_USB Universal Serial Bus printers .It Dv PRN_1394 .Em IEEE 1394 peripherals .El .Pp Printer interface info string is for information only: no implications should be made from its value. .It Dv PRNIOC_RESET Some applications may want to reset the printer state during Setup and/or Cleanup phase using .Dv PRNIOC_RESET command. Reset semantics are device-specific, and in general, applications using this command should be aware of the printer type. .Pp Each .Nm compliant driver is required to accept this request, although performed actions are completely driver-dependent. More information on the .Dv PRNIOC_RESET implementation for the particular driver is available in the corresponding man page and printer manual. .It Dv PRNIOC_GET_1284_DEVID This command can be used to retrieve printer device ID as defined by .Em IEEE 1284-1994 . The .Xr ioctl 2 argument is a pointer to .Vt struct prn_1284_device_id as described below. .Bd -literal -offset 2n struct prn_1284_device_id { uint_t id_len; /* length of buffer */ uint_t id_rlen; /* actual ID length */ char *id_data; /* buffer address */ }; .Ed .Pp For convenience, the two-byte length field is not considered part of device ID string and is not returned in the user buffer. Instead, .Fa id_rlen value shall be set to (length - 2) by the driver, where length is the ID length field value. If buffer length is less than .Fa id_rlen , the driver returns the first .Fa id_len bytes of the ID. .Pp The printer driver must return the most up-to-date value of the device ID. .It Dv PRNIOC_GET_STATUS This command can be used by applications to retrieve current device status. The argument is a pointer to .Vt uint_t , where the status word is returned. Status is a combination of the following bits: .Bl -tag -width PRN_ONLINE .It Dv PRN_ONLINE For devices that support .Dv PRN_HOTPLUG capability, this bit is set when the device is online, otherwise the device is offline. Devices without .Dv PRN_HOTPLUG support should always have this bit set. .It Dv PRN_READY This bit indicates if the device is ready to receive/send data. Applications may use this bit for an outbound flow control. .El .It Dv PRNIOC_GET_1284_STATUS Devices that support .Dv PRN_1284_STATUS capability accept this ioctl to retrieve the device status lines defined in .Em IEEE 1284 for use in Compatibility mode. The following bits may be set by the driver: .Pp .Bl -tag -width PRN_1284_NOFAULT -compact .It Dv PRN_1284_NOFAULT Device is not in error state .It Dv PRN_1284_SELECT Device is selected .It Dv PRN_1284_PE Paper error .It Dv PRN_1284_BUSY Device is busy .El .It Dv PRNIOC_GET_TIMEOUTS This command retrieves current transfer timeout values for the driver. The argument is a pointer to .Vt struct prn_timeouts as described below. .Bd -literal -offset 2n struct prn_timeouts { uint_t tmo_forward; /* forward transfer timeout */ uint_t tmo_reverse; /* reverse transfer timeout */ }; .Ed .Pp .Fa tmo_forward and .Fa tmo_reverse define forward and reverse transfer timeouts in seconds. This command is only valid for drivers that support .Dv PRN_TIMEOUTS capability. .It Dv PRNIOC_SET_TIMEOUTS This command sets current transfer timeout values for the driver. The argument is a pointer to .Vt struct prn_timeouts . See .Sx PRNIOC_GET_TIMEOUTS for description of this structure. This command is only valid for drivers that support .Dv PRN_TIMEOUTS capability. .El .Sh SEE ALSO .Xr close 2 , .Xr ioctl 2 , .Xr read 2 , .Xr write 2 , .Xr ecpp 4D , .Xr lp 4D , .Xr usbprn 4D , .Xr attributes 7 .Rs .%T IEEE Std 1284-1994 .Re