On 06/11/2015 12:27 AM, Marc Zyngier wrote:

On 18/05/15 13:59, Hanjun Guo wrote:

quoted

Introduce acpi_irq_domain for GICv2 core domain instead of referring
to the irq_default_domain, based on that, pass gsi as the argument and
get the gsi in gic_irq_domain_alloc() to add stacked irqdomain support
for ACPI based GICv2 init.

Signed-off-by: Hanjun Guo <redacted>
---
  drivers/acpi/gsi.c                   | 28 +++++++++++++---------------
  drivers/irqchip/irq-gic.c            | 32 +++++++++++++++++---------------
  include/linux/irqchip/arm-gic-acpi.h |  2 ++
  3 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/drivers/acpi/gsi.c b/drivers/acpi/gsi.c
index 38208f2..55b5f31 100644
--- a/drivers/acpi/gsi.c
+++ b/drivers/acpi/gsi.c

@@ -3,6 +3,7 @@
   *
   * Copyright (C) 2015 ARM Ltd.
   * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+ *         Hanjun Guo <hanjun.guo@linaro.org> for stacked irqdomains support
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as

@@ -13,6 +14,8 @@
  #include <linux/irqdomain.h>

  enum acpi_irq_model_id acpi_irq_model;
+/* ACPI core domian pointing to GICv2/3 core domain */
+struct irq_domain *acpi_irq_domain __read_mostly;

How is a single domain pointer going to work when you will have several
domains (GICv2m, ITS)?

This acpi_irq_domain is the core domain which is the parent domain
of GICv2m or ITS.

acpi_irq_domain points to GICv2 or GICv3 domain when the GIC
is initialized.

Crucially, how are you going to perform the
matching of a device with its irq domain?

since every ITS will have a domain, and there is a mapping
from device id to ITS ID in IORT table, then we can match the
device with the ITS irq domain, does it make sense?

Thanks
Hanjun