diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/pnp.txt |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/pnp.txt')
-rw-r--r-- | Documentation/pnp.txt | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/Documentation/pnp.txt b/Documentation/pnp.txt new file mode 100644 index 000000000000..af0f6eabfa1c --- /dev/null +++ b/Documentation/pnp.txt | |||
@@ -0,0 +1,249 @@ | |||
1 | Linux Plug and Play Documentation | ||
2 | by Adam Belay <ambx1@neo.rr.com> | ||
3 | last updated: Oct. 16, 2002 | ||
4 | --------------------------------------------------------------------------------------- | ||
5 | |||
6 | |||
7 | |||
8 | Overview | ||
9 | -------- | ||
10 | Plug and Play provides a means of detecting and setting resources for legacy or | ||
11 | otherwise unconfigurable devices. The Linux Plug and Play Layer provides these | ||
12 | services to compatible drivers. | ||
13 | |||
14 | |||
15 | |||
16 | The User Interface | ||
17 | ------------------ | ||
18 | The Linux Plug and Play user interface provides a means to activate PnP devices | ||
19 | for legacy and user level drivers that do not support Linux Plug and Play. The | ||
20 | user interface is integrated into driverfs. | ||
21 | |||
22 | In addition to the standard driverfs file the following are created in each | ||
23 | device's directory: | ||
24 | id - displays a list of support EISA IDs | ||
25 | options - displays possible resource configurations | ||
26 | resources - displays currently allocated resources and allows resource changes | ||
27 | |||
28 | -activating a device | ||
29 | |||
30 | #echo "auto" > resources | ||
31 | |||
32 | this will invoke the automatic resource config system to activate the device | ||
33 | |||
34 | -manually activating a device | ||
35 | |||
36 | #echo "manual <depnum> <mode>" > resources | ||
37 | <depnum> - the configuration number | ||
38 | <mode> - static or dynamic | ||
39 | static = for next boot | ||
40 | dynamic = now | ||
41 | |||
42 | -disabling a device | ||
43 | |||
44 | #echo "disable" > resources | ||
45 | |||
46 | |||
47 | EXAMPLE: | ||
48 | |||
49 | Suppose you need to activate the floppy disk controller. | ||
50 | 1.) change to the proper directory, in my case it is | ||
51 | /driver/bus/pnp/devices/00:0f | ||
52 | # cd /driver/bus/pnp/devices/00:0f | ||
53 | # cat name | ||
54 | PC standard floppy disk controller | ||
55 | |||
56 | 2.) check if the device is already active | ||
57 | # cat resources | ||
58 | DISABLED | ||
59 | |||
60 | - Notice the string "DISABLED". THis means the device is not active. | ||
61 | |||
62 | 3.) check the device's possible configurations (optional) | ||
63 | # cat options | ||
64 | Dependent: 01 - Priority acceptable | ||
65 | port 0x3f0-0x3f0, align 0x7, size 0x6, 16-bit address decoding | ||
66 | port 0x3f7-0x3f7, align 0x0, size 0x1, 16-bit address decoding | ||
67 | irq 6 | ||
68 | dma 2 8-bit compatible | ||
69 | Dependent: 02 - Priority acceptable | ||
70 | port 0x370-0x370, align 0x7, size 0x6, 16-bit address decoding | ||
71 | port 0x377-0x377, align 0x0, size 0x1, 16-bit address decoding | ||
72 | irq 6 | ||
73 | dma 2 8-bit compatible | ||
74 | |||
75 | 4.) now activate the device | ||
76 | # echo "auto" > resources | ||
77 | |||
78 | 5.) finally check if the device is active | ||
79 | # cat resources | ||
80 | io 0x3f0-0x3f5 | ||
81 | io 0x3f7-0x3f7 | ||
82 | irq 6 | ||
83 | dma 2 | ||
84 | |||
85 | also there are a series of kernel parameters: | ||
86 | pnp_reserve_irq=irq1[,irq2] .... | ||
87 | pnp_reserve_dma=dma1[,dma2] .... | ||
88 | pnp_reserve_io=io1,size1[,io2,size2] .... | ||
89 | pnp_reserve_mem=mem1,size1[,mem2,size2] .... | ||
90 | |||
91 | |||
92 | |||
93 | The Unified Plug and Play Layer | ||
94 | ------------------------------- | ||
95 | All Plug and Play drivers, protocols, and services meet at a central location | ||
96 | called the Plug and Play Layer. This layer is responsible for the exchange of | ||
97 | information between PnP drivers and PnP protocols. Thus it automatically | ||
98 | forwards commands to the proper protocol. This makes writing PnP drivers | ||
99 | significantly easier. | ||
100 | |||
101 | The following functions are available from the Plug and Play Layer: | ||
102 | |||
103 | pnp_get_protocol | ||
104 | - increments the number of uses by one | ||
105 | |||
106 | pnp_put_protocol | ||
107 | - deincrements the number of uses by one | ||
108 | |||
109 | pnp_register_protocol | ||
110 | - use this to register a new PnP protocol | ||
111 | |||
112 | pnp_unregister_protocol | ||
113 | - use this function to remove a PnP protocol from the Plug and Play Layer | ||
114 | |||
115 | pnp_register_driver | ||
116 | - adds a PnP driver to the Plug and Play Layer | ||
117 | - this includes driver model integration | ||
118 | |||
119 | pnp_unregister_driver | ||
120 | - removes a PnP driver from the Plug and Play Layer | ||
121 | |||
122 | |||
123 | |||
124 | Plug and Play Protocols | ||
125 | ----------------------- | ||
126 | This section contains information for PnP protocol developers. | ||
127 | |||
128 | The following Protocols are currently available in the computing world: | ||
129 | - PNPBIOS: used for system devices such as serial and parallel ports. | ||
130 | - ISAPNP: provides PnP support for the ISA bus | ||
131 | - ACPI: among its many uses, ACPI provides information about system level | ||
132 | devices. | ||
133 | It is meant to replace the PNPBIOS. It is not currently supported by Linux | ||
134 | Plug and Play but it is planned to be in the near future. | ||
135 | |||
136 | |||
137 | Requirements for a Linux PnP protocol: | ||
138 | 1.) the protocol must use EISA IDs | ||
139 | 2.) the protocol must inform the PnP Layer of a devices current configuration | ||
140 | - the ability to set resources is optional but prefered. | ||
141 | |||
142 | The following are PnP protocol related functions: | ||
143 | |||
144 | pnp_add_device | ||
145 | - use this function to add a PnP device to the PnP layer | ||
146 | - only call this function when all wanted values are set in the pnp_dev | ||
147 | structure | ||
148 | |||
149 | pnp_init_device | ||
150 | - call this to initialize the PnP structure | ||
151 | |||
152 | pnp_remove_device | ||
153 | - call this to remove a device from the Plug and Play Layer. | ||
154 | - it will fail if the device is still in use. | ||
155 | - automatically will free mem used by the device and related structures | ||
156 | |||
157 | pnp_add_id | ||
158 | - adds a EISA ID to the list of supported IDs for the specified device | ||
159 | |||
160 | For more information consult the source of a protocol such as | ||
161 | /drivers/pnp/pnpbios/core.c. | ||
162 | |||
163 | |||
164 | |||
165 | Linux Plug and Play Drivers | ||
166 | --------------------------- | ||
167 | This section contains information for linux PnP driver developers. | ||
168 | |||
169 | The New Way | ||
170 | ........... | ||
171 | 1.) first make a list of supported EISA IDS | ||
172 | ex: | ||
173 | static const struct pnp_id pnp_dev_table[] = { | ||
174 | /* Standard LPT Printer Port */ | ||
175 | {.id = "PNP0400", .driver_data = 0}, | ||
176 | /* ECP Printer Port */ | ||
177 | {.id = "PNP0401", .driver_data = 0}, | ||
178 | {.id = ""} | ||
179 | }; | ||
180 | |||
181 | Please note that the character 'X' can be used as a wild card in the function | ||
182 | portion (last four characters). | ||
183 | ex: | ||
184 | /* Unkown PnP modems */ | ||
185 | { "PNPCXXX", UNKNOWN_DEV }, | ||
186 | |||
187 | Supported PnP card IDs can optionally be defined. | ||
188 | ex: | ||
189 | static const struct pnp_id pnp_card_table[] = { | ||
190 | { "ANYDEVS", 0 }, | ||
191 | { "", 0 } | ||
192 | }; | ||
193 | |||
194 | 2.) Optionally define probe and remove functions. It may make sense not to | ||
195 | define these functions if the driver already has a reliable method of detecting | ||
196 | the resources, such as the parport_pc driver. | ||
197 | ex: | ||
198 | static int | ||
199 | serial_pnp_probe(struct pnp_dev * dev, const struct pnp_id *card_id, const | ||
200 | struct pnp_id *dev_id) | ||
201 | { | ||
202 | . . . | ||
203 | |||
204 | ex: | ||
205 | static void serial_pnp_remove(struct pnp_dev * dev) | ||
206 | { | ||
207 | . . . | ||
208 | |||
209 | consult /drivers/serial/8250_pnp.c for more information. | ||
210 | |||
211 | 3.) create a driver structure | ||
212 | ex: | ||
213 | |||
214 | static struct pnp_driver serial_pnp_driver = { | ||
215 | .name = "serial", | ||
216 | .card_id_table = pnp_card_table, | ||
217 | .id_table = pnp_dev_table, | ||
218 | .probe = serial_pnp_probe, | ||
219 | .remove = serial_pnp_remove, | ||
220 | }; | ||
221 | |||
222 | * name and id_table can not be NULL. | ||
223 | |||
224 | 4.) register the driver | ||
225 | ex: | ||
226 | |||
227 | static int __init serial8250_pnp_init(void) | ||
228 | { | ||
229 | return pnp_register_driver(&serial_pnp_driver); | ||
230 | } | ||
231 | |||
232 | The Old Way | ||
233 | ........... | ||
234 | |||
235 | a series of compatibility functions have been created to make it easy to convert | ||
236 | |||
237 | ISAPNP drivers. They should serve as a temporary solution only. | ||
238 | |||
239 | they are as follows: | ||
240 | |||
241 | struct pnp_card *pnp_find_card(unsigned short vendor, | ||
242 | unsigned short device, | ||
243 | struct pnp_card *from) | ||
244 | |||
245 | struct pnp_dev *pnp_find_dev(struct pnp_card *card, | ||
246 | unsigned short vendor, | ||
247 | unsigned short function, | ||
248 | struct pnp_dev *from) | ||
249 | |||