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1 .\" $NetBSD: pcibios.4,v 1.16 2008/04/30 13:10:56 martin Exp $
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30 .Dd October 9, 2005
31 .Dt PCIBIOS 4 i386
32 .Os
33 .Sh NAME
34 .Nm pcibios
35 .Nd introduction to PCI BIOS support
36 .Sh SYNOPSIS
37 .Cd "options PCIBIOS"
38 .Cd "options PCIBIOSVERBOSE"
39 .Cd "#options PCIBIOS_IRQS_HINT=0x0a00 #IRQ 9,11"
40 .Cd "#options PCIBIOS_INTR_FIXUP_FORCE"
41 .Cd "options PCIBIOS_INTR_GUESS"
42 .Cd "#options PCIINTR_DEBUG"
43 .Sh INTRODUCTION
44 .Nm
45 provides support for setting up PCI controllers, bridges, and devices
46 using information extracted from the BIOS.
47 .Pp
48 Ideally, the boot firmware of a machine (a.k.a. BIOS) should set
49 up all PCI devices; assigning them I/O and memory addresses and
50 interrupts. Alas, this does not always happen, so there is some
51 PC specific code that can do the initialization when
52 .Nx
53 boots.
54 .Pp
55 Options:
56 .Bl -tag -width PCIBIOS_IRQS_HINT -offset 3n
57 .It Nm PCIBIOS
58 turn on the PCI BIOS support.
59 .It Nm PCIBIOSVERBOSE
60 make the setup procedure verbose.
61 .It Nm PCIBIOS_IRQS_HINT
62 hint for IRQ use.
63 When
64 .Em PCI_INTR_FIXUP
65 cannot guess an adequate IRQ for a device, the hint is used.
66 .Pp
67 The value is a logical or of power-of-2s of allowable interrupts:
68 .Bl -column "XX-0xffff" "XX-0xffff" "XX-0xffff" "XX-0xffff" -compact -offset 2n
69 .It Em "IRQ Value" Ta Em "IRQ Value" Ta Em "IRQ Value" Ta Em "IRQ Value"
70 .It "\& 0 0x0001" Ta " 4 0x0010" Ta " 8 0x0100" Ta "12 0x1000"
71 .It "\& 1 0x0002" Ta " 5 0x0020" Ta " 9 0x0200" Ta "13 0x2000"
72 .It "\& 2 0x0004" Ta " 6 0x0040" Ta "10 0x0400" Ta "14 0x4000"
73 .It "\& 3 0x0008" Ta " 7 0x0080" Ta "11 0x0800" Ta "15 0x8000"
74 .El
75 For example,
76 .Qq Sy options PCIBIOS_IRQS_HINT=0x0a00
77 allows IRQ 9 and IRQ 11.
78 .Pp
79 The kernel global variable
80 .Va pcibios_irqs_hint
81 holds this value,
82 so a user can override this value without kernel recompilation.
83 For example:
84 .Bl -bullet -compact
85 .It
86 To specify this value on the fly, type the following command
87 at the boot prompt to drop into DDB (the in-kernel debugger;
88 you have to specify
89 .Qq Sy options DDB
90 to make kernel with DDB):
91 .Dl Ic boot -d
92 And type the following command on
93 .Qq Sy db\*[Gt]
94 prompt:
95 .Dl Ic write pcibios_irqs_hint 0x0a00
96 Then type the following to continue to boot:
97 .Dl Ic c
98 .It
99 To modify kernel image without kernel recompilation,
100 run the following command on shell:
101 .Dl Ic gdb --write /netbsd
102 And type the following commands at the
103 .Qq Sy (gdb)
104 prompt:
105 .Dl Ic set pcibios_irqs_hint=0xa00
106 .Dl Ic quit
107 .El
108 .It Nm PCIBIOS_INTR_FIXUP_FORCE
109 Some buggy BIOS implementations provide inconsistent
110 information between the PCI Interrupt Configuration Register
111 and the PCI Interrupt Routing table. In such case,
112 the PCI Interrupt Configuration Register takes precedence
113 by default. If this happens, a kernel with
114 .Em PCIBIOSVERBOSE
115 shows
116 .Qq Sy WARNING: preserving irq XX
117 in the PCI routing table.
118 .Pp
119 If
120 .Em PCIBIOS_INTR_FIXUP_FORCE
121 is specified in addition to the
122 .Em PCI_INTR_FIXUP ,
123 the PCI Interrupt Routing table takes precedence.
124 In this case, a kernel with
125 .Em PCIBIOSVERBOSE
126 shows
127 .Qq Sy WARNING: overriding irq XX
128 in the PCI routing table.
129 .It Nm PCIBIOS_INTR_GUESS
130 make
131 .Em PCI_INTR_FIXUP
132 work with unknown interrupt router.
133 .Pp
134 If a PCI interrupt router is not known, normally interrupt
135 configuration will not be touched.
136 .Pp
137 But if
138 .Em PCIBIOS_INTR_GUESS
139 is specified in addition to the
140 .Em PCI_INTR_FIXUP ,
141 and if a PCI interrupt routing table entry indicates that only
142 one IRQ is available for the entry, the IRQ is assumed to be already
143 connected to the device, and corresponding PCI Interrupt
144 Configuration Register will be configured accordingly.
145 .It Nm PCIINTR_DEBUG
146 make the
147 .Em PCI_INTR_FIXUP
148 procedure verbose.
149 .El
150 .Sh SEE ALSO
151 .Xr cardbus 4 ,
152 .Xr pci 4
153 .Sh HISTORY
154 The
155 .Nm
156 code appeared in
157 .Nx 1.5 .
158 .Sh BUGS
159 The
160 .Em PCIBIOS_ADDR_FIXUP
161 option may conflict with the PCI CardBus driver's own
162 address fixup.