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Commit 9a4aa7bf authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet
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pnp.txt: standardize document format 



Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Use a markup for document title;
- use :Author: and :Last updated: for authorship;
- adjust whitespaces where needed;
- mark literal blocks;
- fix a few subtitle markups.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 5da98b82

Documentation/pnp.txt

+192 −151
Original line number Diff line number Diff line 
=================================

Linux Plug and Play Documentation

by Adam Belay <ambx1@neo.rr.com>

last updated: Oct. 16, 2002

---------------------------------------------------------------------------------------

=================================



:Author: Adam Belay <ambx1@neo.rr.com>

:Last updated: Oct. 16, 2002





Overview

--------



Plug and Play provides a means of detecting and setting resources for legacy or

otherwise unconfigurable devices.  The Linux Plug and Play Layer provides these 

services to compatible drivers.







The User Interface

------------------



The Linux Plug and Play user interface provides a means to activate PnP devices

for legacy and user level drivers that do not support Linux Plug and Play.  The 

user interface is integrated into sysfs.



In addition to the standard sysfs file the following are created in each

device's directory:

id - displays a list of support EISA IDs

options - displays possible resource configurations

resources - displays currently allocated resources and allows resource changes

- id - displays a list of support EISA IDs

- options - displays possible resource configurations

- resources - displays currently allocated resources and allows resource changes



-activating a device

activating a device

^^^^^^^^^^^^^^^^^^^



::



	# echo "auto" > resources



this will invoke the automatic resource config system to activate the device



-manually activating a device

manually activating a device

^^^^^^^^^^^^^^^^^^^^^^^^^^^^



::



	# echo "manual <depnum> <mode>" > resources



	<depnum> - the configuration number

	<mode> - static or dynamic

		 static = for next boot

		 dynamic = now



-disabling a device

disabling a device

^^^^^^^^^^^^^^^^^^



::



	# echo "disable" > resources
@@ -47,19 +59,23 @@ this will invoke the automatic resource config system to activate the device 
EXAMPLE:



Suppose you need to activate the floppy disk controller.

1.) change to the proper directory, in my case it is 

/driver/bus/pnp/devices/00:0f



1. change to the proper directory, in my case it is

   /driver/bus/pnp/devices/00:0f::



	# cd /driver/bus/pnp/devices/00:0f

	# cat name

	PC standard floppy disk controller



2.) check if the device is already active

2. check if the device is already active::



	# cat resources

	DISABLED



  - Notice the string "DISABLED".  This means the device is not active.



3.) check the device's possible configurations (optional)

3. check the device's possible configurations (optional)::



	# cat options

	Dependent: 01 - Priority acceptable

	    port 0x3f0-0x3f0, align 0x7, size 0x6, 16-bit address decoding
@@ -72,17 +88,20 @@ Dependent: 02 - Priority acceptable 
	    irq 6

	    dma 2 8-bit compatible



4.) now activate the device

4. now activate the device::



	# echo "auto" > resources



5.) finally check if the device is active

5. finally check if the device is active::



	# cat resources

	io 0x3f0-0x3f5

	io 0x3f7-0x3f7

	irq 6

	dma 2



also there are a series of kernel parameters:

also there are a series of kernel parameters::



	pnp_reserve_irq=irq1[,irq2] ....

	pnp_reserve_dma=dma1[,dma2] ....

	pnp_reserve_io=io1,size1[,io2,size2] ....
@@ -92,6 +111,7 @@ pnp_reserve_mem=mem1,size1[,mem2,size2] .... 


The Unified Plug and Play Layer

-------------------------------



All Plug and Play drivers, protocols, and services meet at a central location

called the Plug and Play Layer.  This layer is responsible for the exchange of 

information between PnP drivers and PnP protocols.  Thus it automatically
@@ -101,64 +121,73 @@ significantly easier. 
The following functions are available from the Plug and Play Layer:



pnp_get_protocol

- increments the number of uses by one

  increments the number of uses by one



pnp_put_protocol

- deincrements the number of uses by one

  deincrements the number of uses by one



pnp_register_protocol

- use this to register a new PnP protocol

  use this to register a new PnP protocol



pnp_unregister_protocol

- use this function to remove a PnP protocol from the Plug and Play Layer

  use this function to remove a PnP protocol from the Plug and Play Layer



pnp_register_driver

- adds a PnP driver to the Plug and Play Layer

- this includes driver model integration

- returns zero for success or a negative error number for failure; count

  adds a PnP driver to the Plug and Play Layer



  this includes driver model integration

  returns zero for success or a negative error number for failure; count

  calls to the .add() method if you need to know how many devices bind to

  the driver



pnp_unregister_driver

- removes a PnP driver from the Plug and Play Layer

  removes a PnP driver from the Plug and Play Layer







Plug and Play Protocols

-----------------------



This section contains information for PnP protocol developers.



The following Protocols are currently available in the computing world:

- PNPBIOS: used for system devices such as serial and parallel ports.

- ISAPNP: provides PnP support for the ISA bus

- ACPI: among its many uses, ACPI provides information about system level 



- PNPBIOS:

    used for system devices such as serial and parallel ports.

- ISAPNP:

    provides PnP support for the ISA bus

- ACPI:

    among its many uses, ACPI provides information about system level

    devices.



It is meant to replace the PNPBIOS.  It is not currently supported by Linux

Plug and Play but it is planned to be in the near future.





Requirements for a Linux PnP protocol:

1.) the protocol must use EISA IDs

2.) the protocol must inform the PnP Layer of a device's current configuration

1. the protocol must use EISA IDs

2. the protocol must inform the PnP Layer of a device's current configuration



- the ability to set resources is optional but preferred.



The following are PnP protocol related functions:



pnp_add_device

- use this function to add a PnP device to the PnP layer

- only call this function when all wanted values are set in the pnp_dev 

  use this function to add a PnP device to the PnP layer



  only call this function when all wanted values are set in the pnp_dev

  structure



pnp_init_device

- call this to initialize the PnP structure

  call this to initialize the PnP structure



pnp_remove_device

- call this to remove a device from the Plug and Play Layer.

- it will fail if the device is still in use.

- automatically will free mem used by the device and related structures

  call this to remove a device from the Plug and Play Layer.

  it will fail if the device is still in use.

  automatically will free mem used by the device and related structures



pnp_add_id

- adds an EISA ID to the list of supported IDs for the specified device

  adds an EISA ID to the list of supported IDs for the specified device



For more information consult the source of a protocol such as

/drivers/pnp/pnpbios/core.c.
@@ -167,12 +196,16 @@ For more information consult the source of a protocol such as 


Linux Plug and Play Drivers

---------------------------



This section contains information for Linux PnP driver developers.



The New Way

...........

1.) first make a list of supported EISA IDS

ex:

^^^^^^^^^^^



1. first make a list of supported EISA IDS



   ex::



	static const struct pnp_id pnp_dev_table[] = {

		/* Standard LPT Printer Port */

		{.id = "PNP0400", .driver_data = 0},
@@ -183,36 +216,43 @@ static const struct pnp_id pnp_dev_table[] = { 


   Please note that the character 'X' can be used as a wild card in the function

   portion (last four characters).

ex:



   ex::



	/* Unknown PnP modems */

	{	"PNPCXXX",		UNKNOWN_DEV	},



   Supported PnP card IDs can optionally be defined.

ex:

   ex::



	static const struct pnp_id pnp_card_table[] = {

		{	"ANYDEVS",		0	},

		{	"",			0	}

	};



2.) Optionally define probe and remove functions.  It may make sense not to 

2. Optionally define probe and remove functions.  It may make sense not to

   define these functions if the driver already has a reliable method of detecting

   the resources, such as the parport_pc driver.

ex:



   ex::



	static int

	serial_pnp_probe(struct pnp_dev * dev, const struct pnp_id *card_id, const

			struct pnp_id *dev_id)

	{

	. . .



ex:

   ex::



	static void serial_pnp_remove(struct pnp_dev * dev)

	{

	. . .



   consult /drivers/serial/8250_pnp.c for more information.



3.) create a driver structure

ex:

3. create a driver structure



   ex::



	static struct pnp_driver serial_pnp_driver = {

		.name		= "serial",
@@ -224,8 +264,9 @@ static struct pnp_driver serial_pnp_driver = { 


   * name and id_table cannot be NULL.



4.) register the driver

ex:

4. register the driver



   ex::



	static int __init serial8250_pnp_init(void)

	{
@@ -233,12 +274,12 @@ static int __init serial8250_pnp_init(void) 
	}



The Old Way

...........

^^^^^^^^^^^



A series of compatibility functions have been created to make it easy to convert

ISAPNP drivers.  They should serve as a temporary solution only.



They are as follows:

They are as follows::



	struct pnp_card *pnp_find_card(unsigned short vendor,

				       unsigned short device,