Re: [PATCH v4 06/10] irqchip / GICv3: Add ACPI support for GICv3+ initialization

From: Hanjun Guo
Date: Tue Aug 11 2015 - 03:20:15 EST

Hi Marc,

On 08/07/2015 12:42 AM, Marc Zyngier wrote:
On 05/08/15 15:00, Hanjun Guo wrote:
On 08/04/2015 09:17 PM, Marc Zyngier wrote:
On 29/07/15 11:08, Hanjun Guo wrote:
From: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>

With the refator of gic_of_init(), GICv3/4 can be initialized
by gic_init_bases() with gic distributor base address and gic
redistributor region(s).

So get the redistributor region base addresses from MADT GIC
redistributor subtable, and the distributor base address from
GICD subtable to init GICv3 irqchip in ACPI way.

Note: GIC redistributor base address may also be provided in
GICC structures on systems supporting GICv3 and above if the GIC
Redistributors are not in the always-on power domain, this
patch didn't implement such feature yet.

Signed-off-by: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
[hj: Rework this patch and fix multi issues]
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
drivers/irqchip/irq-gic-v3.c | 174 +++++++++++++++++++++++++++++++++++++++++--
1 file changed, 169 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index c0b96c6..ebc5604 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -15,6 +15,7 @@
* along with this program. If not, see <>.

+#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/cpu_pm.h>
#include <linux/delay.h>
@@ -25,6 +26,7 @@
#include <linux/percpu.h>
#include <linux/slab.h>

+#include <linux/irqchip/arm-gic-acpi.h>
#include <linux/irqchip/arm-gic-v3.h>

#include <asm/cputype.h>
@@ -802,7 +804,8 @@ static int __init gic_init_bases(void __iomem *dist_base,

if (IS_ENABLED(CONFIG_ARM_GIC_V3_ITS) && gic_dist_supports_lpis())
- its_init(domain_token, &gic_data.rdists, gic_data.domain);
+ its_init(irq_domain_token_to_of_node(domain_token),
+ &gic_data.rdists, gic_data.domain);

This doesn't make much sense. The first parameter to its_init is indeed
supposed to be an of_node, but what is the point of calling its_init if
you *know* you don't have the necessary topological information to parse
the firmware tables?

I don't see *any* code that is going to parse the ITS table in this
series, so please don't call its_init passing a NULL pointer to it. This
is just gross.

OK, the ITS ACPI code is in later patch which combined with IORT. How
about moving it to the GIC of init code temporary?

Just don't call its_init if irq_domain_token_to_of_node(domain_token) is
NULL. But don't call it with a NULL parameter.




As mentioned before, this doesn't work.

hmm, I think we need more discussion for this one, but we need to match
V4 for GICv3 drivers, and everything will be the same in the dirver
as I said before.

And as I said before, you don't need to distinguish v3 from v4 in the
ACPI code. Matching GICv3 is enough.

OK, how about the following code when parsing the GIC version?

* GICv3 driver can find out it's V3 or V4 itself, just set the
* gic_version to V3 to match the driver if firmware presented V4.
if (gic_version == ACPI_MADT_GIC_VERSION_V4)
gic_version = ACPI_MADT_GIC_VERSION_V3;


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at