more multiple dec21140 on ppc
eric.valette at free.fr
Fri Feb 28 09:42:34 UTC 2003
Till Straumann wrote:
> a) I do nothing, boot -> dec driver reports it is using interrupt 10
> which in fact is the ISA interrupt.
> b) Knowing (from the manual) that the ethernet chip is also hooked
> to OpenPIC IRQ2, I use PPCbug (knowing that the on-board dec is
> in slot 0xe) to manually fix the PCI_INTERRUPT_LINE config register:
> CSAW 0 e 0 3c 12 ; B
> I.e. I use PPCBug to write the INTERRUPT_LINE register.
> I added the BSP_PCI_INTERRRUPT_LOWEST_OFFSET because the driver
> currently does not do so. Note that PPCBug takes hex arguments,
> i.e. the 12 value corresponds to decimal 18 which is picked up
> by the driver/BSP and used 1:1 as the 'irq name'.
> After booting up (the _identical_ application binary), the driver
> reports it's now using IRQ 18 and it works fine.
> If I provide the CSAW command with anything else than
> 0xa (isa irq) or 0x12 (OpenPIC IRQ) the driver does not get
> any interrupts, as expected.
So the status is not so bad :
1) This means that someone could just do a kind of "pci init" to change
the irq value because the firmware does not make it. Look at linux
prep-pci.c to see what I mean...
2) Of course the openpic code management should be enhanced as you
proposed to reduce latency,
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