Re: [RFC PATCH 2/6] DRIVERS: IRQCHIP: CROSSBAR: Add support for Crossbar IP

[Sricharan R <r.sricharan@ti.com>]

Hi Kumar,

On Thursday 24 October 2013 03:03 PM, Kumar Gala wrote:
> On Sep 30, 2013, at 8:59 AM, Sricharan R wrote:
>
>> Some socs have a large number of interrupts requests to service
>> the needs of its many peripherals and subsystems. All of the
>> interrupt lines from the subsystems are not needed at the same
>> time, so they have to be muxed to the irq-controller appropriately.
>> In such places a interrupt controllers are preceded by an CROSSBAR
>> that provides flexibility in muxing the device requests to the controller
>> inputs.
>>
>> This driver takes care a allocating a free irq and then configuring the
>> crossbar IP as a part of the mpu's irqchip callbacks. crossbar_init should
>> be called right before the irqchip_init, so that it is setup to handle the
>> irqchip callbacks.
>>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Linus Walleij <linus.walleij@linaro.org>
>> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
>> Cc: Russell King <linux@arm.linux.org.uk>
>> Cc: Tony Lindgren <tony@atomide.com>
>> Cc: Rajendra Nayak <rnayak@ti.com>
>> Cc: Marc Zyngier <marc.zyngier@arm.com>
>> Cc: Grant Likely <grant.likely@linaro.org>
>> Cc: Rob Herring <rob.herring@calxeda.com>
>> Signed-off-by: Sricharan R <r.sricharan@ti.com>
>> ---
>> .../devicetree/bindings/arm/omap/crossbar.txt      |   27 +++
>> drivers/irqchip/Kconfig                            |    8 +
>> drivers/irqchip/Makefile                           |    1 +
>> drivers/irqchip/irq-crossbar.c                     |  195 ++++++++++++++++++++
>> include/linux/irqchip/irq-crossbar.h               |   11 ++
>> 5 files changed, 242 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> create mode 100644 drivers/irqchip/irq-crossbar.c
>> create mode 100644 include/linux/irqchip/irq-crossbar.h
>>
>> diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> new file mode 100644
>> index 0000000..cdec2cd
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> @@ -0,0 +1,27 @@
>> +Some socs have a large number of interrupts requests to service
>> +the needs of its many peripherals and subsystems. All of the
>> +interrupt lines from the subsystems are not needed at the same
>> +time, so they have to be muxed to the irq-controller appropriately.
>> +In such places a interrupt controllers are preceded by an CROSSBAR
>> +that provides flexibility in muxing the device requests to the controller
>> +inputs.
>> +
>> +Required properties:
>> +- compatible : Should be "ti,irq-crossbar"
>> +- reg: Base address and the size of the crossbar registers.
>> +- max-irqs: Total number of irqs available at the interrupt controller.
> Should be 'ti,max-irqs
 Ok, will correct.
>> +- reg-size: Size of a individual register in bytes. Every individual
>> +	    register is assumed to be of same size. Valid sizes are 1, 2, 4.
> Is this something that really needs to be encoded in the dts?
>
> If we keep it should be ti,reg-size
Currently, this is the only IP with a fixed register-size.
 So this can be in the driver also. I thought keeping it
DT will avoid any hard-coding in driver.
>> +- irqs-reserved: List of the reserved irq lines that are not muxed using
>> +		 crossbar. These interrupt lines are reserved in the soc,
>> +		 so crossbar bar driver should not consider them as free
>> +		 lines.
>> +
> ti,irqs-reserved
Ok, will correct
>> +Examples:
>> +		crossbar_mpu: @4a020000 {
> Did you mean for there to be a label and no node name?
>
 ya, name is missing. Will add.
>> +			compatible = "ti,irq-crossbar";
>> +			reg = <0x4a002a48 0x130>;
>> +			max-irqs = <160>;
>> +			reg-size = <2>;
>> +			irqs-reserved = <0 1 2 3 5 6 131 132 139 140>;
>> +		};

Regards,
 Sricharan