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Message-ID: <540E3639.5080807@amd.com>
Date: Mon, 8 Sep 2014 18:05:29 -0500
From: Suravee Suthikulpanit <suravee.suthikulpanit@....com>
To: Mark Rutland <mark.rutland@....com>
CC: Marc Zyngier <Marc.Zyngier@....com>,
"jason@...edaemon.net" <jason@...edaemon.net>,
Pawel Moll <Pawel.Moll@....com>,
Catalin Marinas <Catalin.Marinas@....com>,
Will Deacon <Will.Deacon@....com>,
"tglx@...utronix.de" <tglx@...utronix.de>,
"Harish.Kasiviswanathan@....com" <Harish.Kasiviswanathan@....com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH 1/2 V4] irqchip: gic: Add supports for ARM GICv2m MSI(-X)
On 8/14/2014 12:55 PM, Mark Rutland wrote:
> On Wed, Aug 13, 2014 at 04:00:40PM +0100, suravee.suthikulpanit@....com wrote:
>> From: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
>>
>> 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 <Suravee.Suthikulpanit@....com>
>> Cc: Mark Rutland <Mark.Rutland@....com>
>> Cc: Marc Zyngier <Marc.Zyngier@....com>
>> Cc: Jason Cooper <jason@...edaemon.net>
>> Cc: Catalin Marinas <Catalin.Marinas@....com>
>> Cc: Will Deacon <Will.Deacon@....com>
>> ---
>> 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@...01000 {
>> + 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.
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