[irqchip: irq/irqchip-next] PCI: apple: Change MSI handling to handle 4-cell AIC fwspec form

[irqchip-bot for Hector Martin]

The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID:     89eb1681b73ff584c5678f7185a2d8e3070e9b78
Gitweb:        https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/89eb1681b73ff584c5678f7185a2d8e3070e9b78
Author:        Hector Martin <marcan@xxxxxxxxx>
AuthorDate:    Thu, 10 Mar 2022 04:21:17 +09:00
Committer:     Marc Zyngier <maz@xxxxxxxxxx>
CommitterDate: Thu, 10 Mar 2022 09:49:03 

PCI: apple: Change MSI handling to handle 4-cell AIC fwspec form

AIC2 changes the IRQ fwspec to add a cell. Always use the second-to-last
cell for the MSI handling, so it will work for both AIC1 and AIC2 devices.

Signed-off-by: Hector Martin <marcan@xxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220309192123.152028-2-marcan@xxxxxxxxx
---
 drivers/pci/controller/pcie-apple.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
index 854d951..a2c3c20 100644
--- a/drivers/pci/controller/pcie-apple.c
+++ b/drivers/pci/controller/pcie-apple.c
@@ -219,7 +219,7 @@ static int apple_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 	if (hwirq < 0)
 		return -ENOSPC;
 
-	fwspec.param[1] += hwirq;
+	fwspec.param[fwspec.param_count - 2] += hwirq;
 
 	ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &fwspec);
 	if (ret)