xref: /freebsd/share/man/man4/man4.i386/pnp.4 (revision 23f282aa31e9b6fceacd449020e936e98d6f2298)
1.\" pnp(4) - manual page for the scanner device driver `asc'
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4.\" Copyright (c) 1997 Luigi Rizzo
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31.\" $FreeBSD$
32.\"
33.Dd September 7, 1997
34.Dt PNP 4 i386
35.Os FreeBSD
36.Sh NAME
37.Nm pnp
38.Nd support for PnP devices
39.Sh SYNOPSIS
40.Cd controller pnp0
41.Sh DESCRIPTION
42Support for PnP devices in FreeBSD allows the user to override the
43configuration of PnP cards, and device drivers to fetch/modify
44parameters in the card's configuration space.
45.Pp
46The manual override mechanism requires the kernel to be compiled with
47.Cd options USERCONFIG.
48In this case, the kernel keeps a table of fixed size (20 entries as a
49default) where configuration data are held for PnP devices.
50Each
51PnP card can contain several independent devices (5 or 6 is not
52unusual).
53.Pp
54By booting the kernel with the
55.Dq Fl c
56flag, commands are available to
57modify the configuration of PnP cards.
58Commands start with the
59sequence:
60.Dl pnp CSN LDN
61where CSN and LDN are the Card Select Number and Logical Device Number
62associated to the device.
63Following this sequence any combination of
64the following commands can be used:
65
66.Bl -tag -width "mmmmmmmmmm""
67.It Dv irqN line
68Sets the irq line for interrupt 0 or 1 on the card.
69Line=0 means the line
70is unused.
71.It Dv drqN n
72Sets the drq channel used for DMA 0 or 1 on the card.
73Channel=4 means
74the channel is unused.
75.It Dv portN address
76Sets the base address for the N-th port's range (N=0..7). address=0
77means that the port is not used.
78.It Dv memN address
79Sets the base address for the N-th memory's range (N=0..3). address=0
80means that the memory range is not used.
81.It Dv bios
82Makes the PnP device use the configuration set by the BIOS.
83This
84is the default, and is generally ok if your BIOS has PnP support.
85If BIOS is used, then other parameters are ignored except "flags".
86.It Dv os
87Makes the PnP device to use the configuration specified in this entry.
88.It Dv enable
89Enables the PnP device.
90.It Dv disable
91Disables the PnP device.
92.It Dv delete
93Frees the entry used for the device, so that it can be used for
94another device with a different CSN/LDN pair.
95.It Dv flags
96Sets the value of a 32-bit flags entry which is passed to the device
97driver.
98This can be used to set special operation modes (e.g. SB vs. WSS
99emulation on some sound cards, etc.).
100.El
101.Pp
102The current content of the table can be printed using the
103.Ic ls
104command in userconfig.
105In addition to modifications done by the user,
106the table contains an entry for
107all logical devices accessed by a PnP device driver.
108.Pp
109Modifications to
110the table will be saved to the boot image on the filesystem by the
111.Xr kget 8
112command.
113.Pp
114.Sh DEVICE DRIVER SUPPORT FOR PnP
115PnP devices are automatically recognized and configured by the kernel.
116A PnP device is identified by the following data structure:
117.Bd -literal
118struct pnp_device {
119	char	*pd_name;
120	char	*(*pd_probe ) (u_long csn, u_long vendor_id);
121	void	(*pd_attach ) (u_long csn, u_long vend_id, char * name,
122		    struct isa_device *dev);
123	u_long	*pd_count;
124	u_int	*imask;
125	struct	isa_device dev;
126};
127.Ed
128.Pp
129The probe routine must check that the vendor_id passed is a
130recognized one, that any necessary devices on the card are enabled,
131and returns a NULL value in case of failure or a non-NULL value
132(generally a pointer to the device name) unpon success.  In the probe
133routine, the function
134.Fn read_pnp_parms
135can be used to check that the logical devices are enabled.
136.Pp
137The attach routine should do all the necessary initialization, enable
138the PnP card to ISA accesses, fetch the configuration, and call the ISA
139driver for the device.
140.Pp
141The following routines and data structures can be used:
142.Bl -tag -width "xxxxxxxxxx"
143.It Dv struct pnp_cinfo
144This data structure (defined in /sys/i386/isa/pnp.h) contains all
145informations related to a PnP logical device.
146.It Fn read_pnp_parms "struct pnp_cinfo *d" "int ldn"
147This function returns the configuration of the requested
148logical device.
149It is not possible to specify a CSN since this function
150is only meant to be used during probe and attach routines
151.It Fn write_pnp_parms "struct pnp_cinfo *d" "int ldn"
152This function sets the parameters of the requested logical device.
153At
154the same time, it updates the entry in the kernel override table.
155Device drivers in general should
156.Em not
157modify the configuration of a device, since either the BIOS or the user
158(through userconfig) should know better what to do.
159In particular,
160device driver
161.Em should not enable
162a logical device which has
163been found disabled,
164since this would defeat the override mechanism in userconfig.
165Device
166drivers may disable a logical device, or a port range, etc, but should
167do so only that particular device or parameter is known to cause
168troubles.
169.It Fn enable_pnp_card void
170This function
171.Em must
172be used in the attach routine
173.Em only ,
174before accessing the card's ISA ports/memory address ranges.
175.El
176.Pp
177.Sh SEE ALSO
178.Xr kget 8
179.Sh BUGS
180There is no support for visual configuration of PnP devices.
181It would be nice to have commands in userconfig to fetch the
182configuration of PnP devices.
183.Sh AUTHORS
184PnP support was written by
185.An Luigi Rizzo ,
186based on initial work done by
187.An Sujal Patel .
188.Sh HISTORY
189The
190.Nm
191driver first appeared in
192.Fx 2.2.5 .
193