[PATCH v18 03/15] irqchip/gic-v3-its: Set IRQ_DOMAIN_FLAG_MSI_IMMUTABLE for ITS

Frank Li
2025-04-14T18:31:33Z

Set the IRQ_DOMAIN_FLAG_MSI_IMMUTABLE flag for ITS, as it does not change
the address/data pair after setup.

Ensure compatibility with MSI users, such as PCIe Endpoint Doorbell, which
require the address/data pair to remain unchanged. Enable PCIe endpoints to
use ITS for triggering doorbells from the PCIe Root Complex (RC) side.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
change from v14 to v16
- none

change from v13 to v12
- roll back to v12 version because Marc Zyngier have concern about add
DOMAIN_BUS_DEVICE_PCI_EP_MSI.
https://lore.kernel.org/imx/861pxfq315.wl-maz@kernel.org/

change from v11 to v12
- new patch
---
drivers/irqchip/irq-gic-v3-its.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 0115ad6c82593..fd6e7c170d37e 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -5140,7 +5140,7 @@ static int its_init_domain(struct its_node *its)
irq_domain_update_bus_token(inner_domain, DOMAIN_BUS_NEXUS);

inner_domain->msi_parent_ops = &gic_v3_its_msi_parent_ops;
- inner_domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT;
+ inner_domain->flags |= IRQ_DOMAIN_FLAG_MSI_PARENT | IRQ_DOMAIN_FLAG_MSI_IMMUTABLE;

return 0;
}

--
2.34.1