Subject: [PATCH 1/2 V4] irqchip: gic: Add supports for ARM GICv2m MSI(-X)

From: [email-masked] (Suravee Suthikulpanit)
Date: Mon, 8 Sep 2014 18:05:29 -0500

On 8/14/2014 12:55 PM, Mark Rutland wrote:
> On Wed, Aug 13, 2014 at 04:00:40PM +0100, suravee.suthikulpanit at amd.com wrote:
>> From: Suravee Suthikulpanit <[email-masked]>
>>
>> ARM GICv2m specification extends GICv2 to support MSI(-X) with
>> a new set of register frame. This patch introduces support for
>> the non-secure GICv2m register frame. Currently, GICV2m is available
>> in certain version of GIC-400.
>>
>> The patch introduces a new property in ARM gic binding, the v2m subnode.
>> It is optional.
>>
>> Signed-off-by: Suravee Suthikulpanit <[email-masked]>
>> Cc: Mark Rutland <[email-masked]>
>> Cc: Marc Zyngier <[email-masked]>
>> Cc: Jason Cooper <[email-masked]>
>> Cc: Catalin Marinas <[email-masked]>
>> Cc: Will Deacon <[email-masked]>
>> ---
>>   Documentation/devicetree/bindings/arm/gic.txt |  32 ++++
>>   drivers/irqchip/Kconfig                       |   7 +
>>   drivers/irqchip/Makefile                      |   1 +
>>   drivers/irqchip/irq-gic-v2m.c                 | 215 ++++++++++++++++++++++++++
>>   drivers/irqchip/irq-gic.c                     |  75 +++++----
>>   drivers/irqchip/irq-gic.h                     |  48 ++++++
>>   6 files changed, 348 insertions(+), 30 deletions(-)
>>   create mode 100644 drivers/irqchip/irq-gic-v2m.c
>>   create mode 100644 drivers/irqchip/irq-gic.h
>>
>> diff --git a/Documentation/devicetree/bindings/arm/gic.txt b/Documentation/devicetree/bindings/arm/gic.txt
>> index 5573c08..8a64179 100644
>> --- a/Documentation/devicetree/bindings/arm/gic.txt
>> +++ b/Documentation/devicetree/bindings/arm/gic.txt
>> @@ -95,3 +95,35 @@ Example:
>>                        <0x2c006000 0x2000>;
>>                  interrupts = <1 9 0xf04>;
>>          };
>> +
>> +
>> +* GICv2m extension for MSI/MSI-x support (Optional)
>> +
>> +Certain revision of GIC-400 supports MSI/MSI-x via V2M register frame.
>> +This is enabled by specifying v2m sub-node.
>> +
>> +Required properties:
>> +
>> +- msi-controller : Identifies the node as an MSI controller.
>> +
>> +- reg : GICv2m MSI interface register base and size
>> +
>> +Example:
>> +
>> +       interrupt-controller at e1101000 {
>> +               compatible = "arm,gic-400";
>> +               #interrupt-cells = <3>;
>> +               #address-cells = <2>;
>> +               #size-cells = <2>;
>> +               interrupt-controller;
>> +               interrupts = <1 8 0xf04>;
>> +               ranges = <0 0 0 0xe1100000 0 0x100000>;
>> +               reg = <0x0 0xe1110000 0 0x01000>,
>> +                     <0x0 0xe112f000 0 0x02000>,
>> +                     <0x0 0xe1140000 0 0x10000>,
>> +                     <0x0 0xe1160000 0 0x10000>;
>> +               v2m {
>> +                       msi-controller;
>> +                       reg = <0x0 0x80000 0 0x1000>;
>> +               };
>> +       };
>
> [...]
>
>> @@ -1009,6 +1012,16 @@ gic_of_init(struct device_node *node, struct device_node *parent)
>>          if (of_property_read_u32(node, "cpu-offset", &percpu_offset))
>>                  percpu_offset = 0;
>>
>> +       gic_data[gic_cnt].irq_chip = &gic_chip;
>> +
>> +       /* Currently, we only support one v2m subnode. */
>> +       child = of_get_child_by_name(node, "v2m");
>> +       if (child) {
>> +               ret = gicv2m_of_init(child, &gic_data[gic_cnt]);
>> +               if (ret)
>> +                       return ret;
>> +       }
>
> I can't see how you'd sanely expand this to multiple children, which was
> the main point of having a separate node for the M block.
>
> Give the M block a compatible string and look for children with that
> string.

Mark,

I am making change in the struct gic_chip_data to contain "v2m_list" (instead of just
a single struct v2m_data). This way, it is clear on how we should handle multiple v2m nodes
within a GIC.

As for the device tree binding, in order to handle multiple v2m nodes within a GIC,
it should not require adding another compatibility ID as it seems too complicate
to have GIC node with multiple compat IDs).

	v2m0 {
		msi-controller;
		reg = <0 0x80000 0 0x10000>;	
	};

	v2m1 {
		msi-controller;
		reg = <0 0x90000 0 0x10000>;
	};

This should work since the PCI controller uses "of_pci_find_msi_chip_by_node()" to locate the msi_chip,
we can simply just use "v2m0" or "v2m1" to specify this.

Thanks,

Suravee.