Re: [PATCH V3 16/16] irqchip: crossbar: allow for quirky hardware with direct hardwiring of GIC

From: Sricharan R
Date: Mon Jun 23 2014 - 03:25:23 EST


Hi Jason,

On Saturday 21 June 2014 08:27 AM, Jason Cooper wrote:
> On Mon, Jun 16, 2014 at 04:53:16PM +0530, Sricharan R wrote:
>> From: Nishanth Menon <nm@xxxxxx>
>>
>> On certain platforms such as DRA7, SPIs 0, 1, 2, 3, 5, 6, 10, 131,
>> 132, 133 are direct wired to hardware blocks bypassing crossbar.
>> This quirky implementation is *NOT* supposed to be the expectation
>> of crossbar hardware usage. However, these are already marked in our
>> description of the hardware with SKIP and RESERVED where appropriate.
>>
>> Unfortunately, we need to be able to refer to these hardwired IRQs.
>> So, to request these, crossbar driver can use the existing information
>> from it's table that these SKIP/RESERVED maps are direct wired sources
>> and generic allocation/programming of crossbar should be avoided.
>>
>> Signed-off-by: Nishanth Menon <nm@xxxxxx>
>> Signed-off-by: Sricharan R <r.sricharan@xxxxxx>
>> ---
>> .../devicetree/bindings/arm/omap/crossbar.txt | 12 ++++++++++--
>> drivers/irqchip/irq-crossbar.c | 20 ++++++++++++++++++--
>> 2 files changed, 28 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> index 8210ea4..438ccab 100644
>> --- a/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> +++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> @@ -42,8 +42,10 @@ Documentation/devicetree/bindings/arm/gic.txt for further details.
>>
>> An interrupt consumer on an SoC using crossbar will use:
>> interrupts = <GIC_SPI request_number interrupt_level>
>> -request number shall be between 0 to that described by
>> -"ti,max-crossbar-sources"
>> +When the request number is between 0 to that described by
>> +"ti,max-crossbar-sources", it is assumed to be a crossbar mapping. If the
>> +request_number is greater than "ti,max-crossbar-sources", then it is mapped as a
>> +quirky hardware mapping direct to GIC.
>>
>> Example:
>> device_x@0x4a023000 {
>> @@ -51,3 +53,9 @@ Example:
>> interrupts = <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
>> ...
>> };
>> +
>> + device_y@0x4a033000 {
>> + /* Direct mapped GIC SPI 1 used */
>> + interrupts = <GIC_SPI 401 IRQ_TYPE_LEVEL_HIGH>;
>
> Ideally, I'd like to see a macro here so that it's clear that we crossed
> a magic threshold. eg:
>
> #define MAX_SOURCES 400
> #define DIRECT_IRQ(irq) (MAX_SOURCES + irq)
> ...
> interrupts = <GIC_SPI DIRECT_IRQ(1) IRQ_TYPE_LEVEL_HIGH>;
>
> and, then:
>
> ti,max-crossbar-sources = <MAX_SOURCES>;
>
Ok, thats more good for readability. Will add that macro then.

Regards,
Sricharan
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