Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
[linux-2.6-block.git] / Documentation / pnp.txt
CommitLineData
9a4aa7bf 1=================================
1da177e4 2Linux Plug and Play Documentation
9a4aa7bf 3=================================
1da177e4 4
9a4aa7bf
MCC
5:Author: Adam Belay <ambx1@neo.rr.com>
6:Last updated: Oct. 16, 2002
1da177e4
LT
7
8
9Overview
10--------
9a4aa7bf
MCC
11
12Plug and Play provides a means of detecting and setting resources for legacy or
1da177e4
LT
13otherwise unconfigurable devices. The Linux Plug and Play Layer provides these
14services to compatible drivers.
15
16
1da177e4
LT
17The User Interface
18------------------
9a4aa7bf
MCC
19
20The Linux Plug and Play user interface provides a means to activate PnP devices
1da177e4 21for legacy and user level drivers that do not support Linux Plug and Play. The
b1c7192d 22user interface is integrated into sysfs.
1da177e4 23
b1c7192d 24In addition to the standard sysfs file the following are created in each
1da177e4 25device's directory:
9a4aa7bf
MCC
26- id - displays a list of support EISA IDs
27- options - displays possible resource configurations
28- resources - displays currently allocated resources and allows resource changes
1da177e4 29
9a4aa7bf
MCC
30activating a device
31^^^^^^^^^^^^^^^^^^^
1da177e4 32
9a4aa7bf
MCC
33::
34
35 # echo "auto" > resources
1da177e4
LT
36
37this will invoke the automatic resource config system to activate the device
38
9a4aa7bf
MCC
39manually activating a device
40^^^^^^^^^^^^^^^^^^^^^^^^^^^^
41
42::
43
44 # echo "manual <depnum> <mode>" > resources
1da177e4 45
9a4aa7bf
MCC
46 <depnum> - the configuration number
47 <mode> - static or dynamic
48 static = for next boot
49 dynamic = now
1da177e4 50
9a4aa7bf
MCC
51disabling a device
52^^^^^^^^^^^^^^^^^^
1da177e4 53
9a4aa7bf
MCC
54::
55
56 # echo "disable" > resources
1da177e4
LT
57
58
59EXAMPLE:
60
61Suppose you need to activate the floppy disk controller.
9a4aa7bf
MCC
62
631. change to the proper directory, in my case it is
64 /driver/bus/pnp/devices/00:0f::
65
66 # cd /driver/bus/pnp/devices/00:0f
67 # cat name
68 PC standard floppy disk controller
69
702. check if the device is already active::
71
72 # cat resources
73 DISABLED
74
75 - Notice the string "DISABLED". This means the device is not active.
76
773. check the device's possible configurations (optional)::
78
79 # cat options
80 Dependent: 01 - Priority acceptable
81 port 0x3f0-0x3f0, align 0x7, size 0x6, 16-bit address decoding
82 port 0x3f7-0x3f7, align 0x0, size 0x1, 16-bit address decoding
83 irq 6
84 dma 2 8-bit compatible
85 Dependent: 02 - Priority acceptable
86 port 0x370-0x370, align 0x7, size 0x6, 16-bit address decoding
87 port 0x377-0x377, align 0x0, size 0x1, 16-bit address decoding
88 irq 6
89 dma 2 8-bit compatible
90
914. now activate the device::
92
93 # echo "auto" > resources
94
955. finally check if the device is active::
96
97 # cat resources
98 io 0x3f0-0x3f5
99 io 0x3f7-0x3f7
100 irq 6
101 dma 2
102
103also there are a series of kernel parameters::
104
105 pnp_reserve_irq=irq1[,irq2] ....
106 pnp_reserve_dma=dma1[,dma2] ....
107 pnp_reserve_io=io1,size1[,io2,size2] ....
108 pnp_reserve_mem=mem1,size1[,mem2,size2] ....
1da177e4
LT
109
110
111
112The Unified Plug and Play Layer
113-------------------------------
9a4aa7bf
MCC
114
115All Plug and Play drivers, protocols, and services meet at a central location
1da177e4
LT
116called the Plug and Play Layer. This layer is responsible for the exchange of
117information between PnP drivers and PnP protocols. Thus it automatically
118forwards commands to the proper protocol. This makes writing PnP drivers
119significantly easier.
120
121The following functions are available from the Plug and Play Layer:
122
123pnp_get_protocol
9a4aa7bf 124 increments the number of uses by one
1da177e4
LT
125
126pnp_put_protocol
9a4aa7bf 127 deincrements the number of uses by one
1da177e4
LT
128
129pnp_register_protocol
9a4aa7bf 130 use this to register a new PnP protocol
1da177e4
LT
131
132pnp_unregister_protocol
9a4aa7bf 133 use this function to remove a PnP protocol from the Plug and Play Layer
1da177e4
LT
134
135pnp_register_driver
9a4aa7bf
MCC
136 adds a PnP driver to the Plug and Play Layer
137
138 this includes driver model integration
139 returns zero for success or a negative error number for failure; count
982c6094
BH
140 calls to the .add() method if you need to know how many devices bind to
141 the driver
1da177e4
LT
142
143pnp_unregister_driver
9a4aa7bf 144 removes a PnP driver from the Plug and Play Layer
1da177e4
LT
145
146
147
148Plug and Play Protocols
149-----------------------
9a4aa7bf
MCC
150
151This section contains information for PnP protocol developers.
1da177e4
LT
152
153The following Protocols are currently available in the computing world:
9a4aa7bf
MCC
154
155- PNPBIOS:
156 used for system devices such as serial and parallel ports.
157- ISAPNP:
158 provides PnP support for the ISA bus
159- ACPI:
160 among its many uses, ACPI provides information about system level
161 devices.
162
1da177e4
LT
163It is meant to replace the PNPBIOS. It is not currently supported by Linux
164Plug and Play but it is planned to be in the near future.
165
166
167Requirements for a Linux PnP protocol:
9a4aa7bf
MCC
1681. the protocol must use EISA IDs
1692. the protocol must inform the PnP Layer of a device's current configuration
170
a982ac06 171- the ability to set resources is optional but preferred.
1da177e4
LT
172
173The following are PnP protocol related functions:
174
175pnp_add_device
9a4aa7bf
MCC
176 use this function to add a PnP device to the PnP layer
177
178 only call this function when all wanted values are set in the pnp_dev
179 structure
1da177e4
LT
180
181pnp_init_device
9a4aa7bf 182 call this to initialize the PnP structure
1da177e4
LT
183
184pnp_remove_device
9a4aa7bf
MCC
185 call this to remove a device from the Plug and Play Layer.
186 it will fail if the device is still in use.
187 automatically will free mem used by the device and related structures
1da177e4
LT
188
189pnp_add_id
9a4aa7bf 190 adds an EISA ID to the list of supported IDs for the specified device
1da177e4
LT
191
192For more information consult the source of a protocol such as
193/drivers/pnp/pnpbios/core.c.
194
195
196
197Linux Plug and Play Drivers
198---------------------------
9a4aa7bf
MCC
199
200This section contains information for Linux PnP driver developers.
1da177e4
LT
201
202The New Way
9a4aa7bf
MCC
203^^^^^^^^^^^
204
2051. first make a list of supported EISA IDS
206
207 ex::
208
209 static const struct pnp_id pnp_dev_table[] = {
210 /* Standard LPT Printer Port */
211 {.id = "PNP0400", .driver_data = 0},
212 /* ECP Printer Port */
213 {.id = "PNP0401", .driver_data = 0},
214 {.id = ""}
215 };
216
217 Please note that the character 'X' can be used as a wild card in the function
218 portion (last four characters).
219
220 ex::
221
4ae0edc2 222 /* Unknown PnP modems */
1da177e4
LT
223 { "PNPCXXX", UNKNOWN_DEV },
224
9a4aa7bf
MCC
225 Supported PnP card IDs can optionally be defined.
226 ex::
227
228 static const struct pnp_id pnp_card_table[] = {
229 { "ANYDEVS", 0 },
230 { "", 0 }
231 };
232
2332. Optionally define probe and remove functions. It may make sense not to
234 define these functions if the driver already has a reliable method of detecting
235 the resources, such as the parport_pc driver.
236
237 ex::
238
239 static int
240 serial_pnp_probe(struct pnp_dev * dev, const struct pnp_id *card_id, const
241 struct pnp_id *dev_id)
242 {
243 . . .
244
245 ex::
246
247 static void serial_pnp_remove(struct pnp_dev * dev)
248 {
249 . . .
250
251 consult /drivers/serial/8250_pnp.c for more information.
252
2533. create a driver structure
254
255 ex::
256
257 static struct pnp_driver serial_pnp_driver = {
258 .name = "serial",
259 .card_id_table = pnp_card_table,
260 .id_table = pnp_dev_table,
261 .probe = serial_pnp_probe,
262 .remove = serial_pnp_remove,
263 };
264
265 * name and id_table cannot be NULL.
266
2674. register the driver
268
269 ex::
270
271 static int __init serial8250_pnp_init(void)
272 {
273 return pnp_register_driver(&serial_pnp_driver);
274 }
1da177e4
LT
275
276The Old Way
9a4aa7bf 277^^^^^^^^^^^
1da177e4 278
a64061e1 279A series of compatibility functions have been created to make it easy to convert
1da177e4
LT
280ISAPNP drivers. They should serve as a temporary solution only.
281
9a4aa7bf 282They are as follows::
1da177e4 283
9a4aa7bf
MCC
284 struct pnp_card *pnp_find_card(unsigned short vendor,
285 unsigned short device,
286 struct pnp_card *from)
1da177e4 287
9a4aa7bf
MCC
288 struct pnp_dev *pnp_find_dev(struct pnp_card *card,
289 unsigned short vendor,
290 unsigned short function,
291 struct pnp_dev *from)
1da177e4 292