diff options
| author | BALATON Zoltan via <qemu-ppc@nongnu.org> | 2021-01-03 02:09:33 +0100 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2021-01-06 11:09:59 +1100 |
| commit | 2a9cf49598c65d117b53f72d895ac3c20a3027bc (patch) | |
| tree | 0c441dd2affe7369e814e8ee2642676742446da4 /hw | |
| parent | 038da2adf0262b17ff4bf373178ca018bd817721 (diff) | |
ppc440_pcix: Improve comment for IRQ mapping
The code mapping all PCI interrupts to a single CPU IRQ works but is
not trivial so document it in a comment.
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Message-Id: <c25c0310510672b58466e795fd701e65e8f1ff97.1609636173.git.balaton@eik.bme.hu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/ppc/ppc440_pcix.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/hw/ppc/ppc440_pcix.c b/hw/ppc/ppc440_pcix.c index ee952314c8..eb1290ffc8 100644 --- a/hw/ppc/ppc440_pcix.c +++ b/hw/ppc/ppc440_pcix.c @@ -415,8 +415,15 @@ static void ppc440_pcix_reset(DeviceState *dev) s->sts = 0; } -/* All pins from each slot are tied to a single board IRQ. - * This may need further refactoring for other boards. */ +/* + * All four IRQ[ABCD] pins from all slots are tied to a single board + * IRQ, so our mapping function here maps everything to IRQ 0. + * The code in pci_change_irq_level() tracks the number of times + * the mapped IRQ is asserted and deasserted, so if multiple devices + * assert an IRQ at the same time the behaviour is correct. + * + * This may need further refactoring for boards that use multiple IRQ lines. + */ static int ppc440_pcix_map_irq(PCIDevice *pci_dev, int irq_num) { trace_ppc440_pcix_map_irq(pci_dev->devfn, irq_num, 0); |