pcibios(4) - NetBSD Manual Pages

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PCIBIOS(4)           NetBSD/i386 Kernel Interfaces Manual           PCIBIOS(4)


NAME

     pcibios -- introduction to PCI BIOS support


SYNOPSIS

     options   PCIBIOS
     options   PCIBIOSVERBOSE
     #options  PCIBIOS_IRQS_HINT=0x0a00 #IRQ 9,11
     #options  PCIBIOS_INTR_FIXUP_FORCE
     options   PCIBIOS_INTR_GUESS
     #options  PCIINTR_DEBUG


INTRODUCTION

     pcibios provides support for setting up PCI controllers, bridges, and
     devices using information extracted from the BIOS.

     Ideally, the boot firmware of a machine (a.k.a. BIOS) should set up all
     PCI devices; assigning them I/O and memory addresses and interrupts.
     Alas, this does not always happen, so there is some PC specific code that
     can do the initialization when NetBSD boots.

     Options:

        PCIBIOS            turn on the PCI BIOS support.

        PCIBIOSVERBOSE     make the setup procedure verbose.

        PCIBIOS_IRQS_HINT  hint for IRQ use.  When PCI_INTR_FIXUP cannot guess
                           an adequate IRQ for a device, the hint is used.

                           The value is a logical or of power-of-2s of allow-
                           able interrupts:
                             IRQ Value    IRQ Value    IRQ Value    IRQ Value
                              0 0x0001     4 0x0010     8 0x0100    12 0x1000
                              1 0x0002     5 0x0020     9 0x0200    13 0x2000
                              2 0x0004     6 0x0040    10 0x0400    14 0x4000
                              3 0x0008     7 0x0080    11 0x0800    15 0x8000
                           For example, "options PCIBIOS_IRQS_HINT=0x0a00"
                           allows IRQ 9 and IRQ 11.

                           The kernel global variable pcibios_irqs_hint holds
                           this value, so a user can override this value with-
                           out kernel recompilation.  For example:
                           ·   To specify this value on the fly, type the fol-
                               lowing command at the boot prompt to drop into
                               DDB (the in-kernel debugger; you have to spec-
                               ify "options DDB" to make kernel with DDB):
                                     boot -d
                               And type the following command on "db>" prompt:
                                     write pcibios_irqs_hint 0x0a00
                               Then type the following to continue to boot:
                                     c
                           ·   To modify kernel image without kernel recompi-
                               lation, run the following command on shell:
                                     gdb --write /netbsd
                               And type the following commands at the "(gdb)"
                               prompt:
                                     set pcibios_irqs_hint=0xa00
                                     quit

        PCIBIOS_INTR_FIXUP_FORCE
                           Some buggy BIOS implementations provide inconsis-
                           tent information between the PCI Interrupt Configu-
                           ration Register and the PCI Interrupt Routing ta-
                           ble.  In such case, the PCI Interrupt Configuration
                           Register takes precedence by default.  If this hap-
                           pens, a kernel with PCIBIOSVERBOSE shows "WARNING:
                           preserving irq XX" in the PCI routing table.

                           If PCIBIOS_INTR_FIXUP_FORCE is specified in addi-
                           tion to the PCI_INTR_FIXUP, the PCI Interrupt Rout-
                           ing table takes precedence.  In this case, a kernel
                           with PCIBIOSVERBOSE shows "WARNING: overriding irq
                           XX" in the PCI routing table.

        PCIBIOS_INTR_GUESS
                           make PCI_INTR_FIXUP work with unknown interrupt
                           router.

                           If a PCI interrupt router is not known, normally
                           interrupt configuration will not be touched.

                           But if PCIBIOS_INTR_GUESS is specified in addition
                           to the PCI_INTR_FIXUP, and if a PCI interrupt rout-
                           ing table entry indicates that only one IRQ is
                           available for the entry, the IRQ is assumed to be
                           already connected to the device, and corresponding
                           PCI Interrupt Configuration Register will be con-
                           figured accordingly.

        PCIINTR_DEBUG      make the PCI_INTR_FIXUP procedure verbose.


SEE ALSO

     cardbus(4), pci(4)


HISTORY

     The pcibios code appeared in NetBSD 1.5.


BUGS

     The PCIBIOS_ADDR_FIXUP option may conflict with the PCI CardBus driver's
     own address fixup.

NetBSD 10.1                     October 9, 2005                    NetBSD 10.1