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[PULL 20/22] ppc440_pcix: Improve comment for IRQ mapping
From: |
David Gibson |
Subject: |
[PULL 20/22] ppc440_pcix: Improve comment for IRQ mapping |
Date: |
Wed, 6 Jan 2021 14:38:14 +1100 |
From: BALATON Zoltan via <qemu-ppc@nongnu.org>
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>
---
hw/ppc/ppc440_pcix.c | 11 +++++++++--
1 file 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);
--
2.29.2
- [PULL 09/22] spapr: Fix buffer overflow in spapr_numa_associativity_init(), (continued)
- [PULL 09/22] spapr: Fix buffer overflow in spapr_numa_associativity_init(), David Gibson, 2021/01/05
- [PULL 11/22] spapr: Fix reset of transient DR connectors, David Gibson, 2021/01/05
- [PULL 12/22] spapr: Introduce spapr_drc_reset_all(), David Gibson, 2021/01/05
- [PULL 08/22] spapr: Allow memory unplug to always succeed, David Gibson, 2021/01/05
- [PULL 13/22] spapr: Use spapr_drc_reset_all() at machine reset, David Gibson, 2021/01/05
- [PULL 14/22] spapr: Add drc_ prefix to the DRC realize and unrealize functions, David Gibson, 2021/01/05
- [PULL 15/22] ppc: Fix build with --without-default-devices, David Gibson, 2021/01/05
- [PULL 16/22] ppc: Simplify reverse dependencies of POWERNV and PSERIES on XICS and XIVE, David Gibson, 2021/01/05
- [PULL 07/22] spapr: Fix DR properties of the root node, David Gibson, 2021/01/05
- [PULL 10/22] spapr: Call spapr_drc_reset() for all DRCs at CAS, David Gibson, 2021/01/05
- [PULL 20/22] ppc440_pcix: Improve comment for IRQ mapping,
David Gibson <=
- [PULL 19/22] sam460ex: Remove FDT_PPC dependency from KConfig, David Gibson, 2021/01/05
- [PULL 21/22] ppc440_pcix: Fix register write trace event, David Gibson, 2021/01/05
- [PULL 18/22] ppc4xx: Move common dependency on serial to common option, David Gibson, 2021/01/05
- [PULL 17/22] pnv: Fix reverse dependency on PCI express root ports, David Gibson, 2021/01/05
- [PULL 22/22] ppc440_pcix: Fix up pci config access, David Gibson, 2021/01/05
- Re: [PULL 00/22] ppc-for-6.0 queue 20210106, BALATON Zoltan, 2021/01/06
- Re: [PULL 00/22] ppc-for-6.0 queue 20210106, Peter Maydell, 2021/01/06