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 9.0 October 9, 2005 NetBSD 9.0
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