[PATCH v4 3/7] ARM: Exynos: add device tree support for MCT controller driver

[Thomas Abraham]

Hi Marc,

On 21 January 2013 05:46, Mark Rutland <mark.rutland at arm.com> wrote:
> On Mon, Jan 21, 2013 at 10:02:18AM +0000, Thomas Abraham wrote:
>> Allow the MCT controller base address and interrupts to be obtained from
>> device tree and remove unused static definitions of these. The non-dt support
>> for Exynos5250 is removed but retained for Exynos4210 based platforms.
>>
>> Cc: Changhwan Youn <chaos.youn at samsung.com>
>> Signed-off-by: Thomas Abraham <thomas.abraham at linaro.org>
>> ---
>>  .../bindings/timer/samsung,exynos4210-mct.txt      |   68 ++++++++++++++++++++
>>  arch/arm/mach-exynos/include/mach/irqs.h           |    6 --
>>  arch/arm/mach-exynos/mct.c                         |   49 +++++++++++----
>>  3 files changed, 105 insertions(+), 18 deletions(-)
>>  create mode 100644 Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>>
>> diff --git a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>> new file mode 100644
>> index 0000000..cb47bfb
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
>> @@ -0,0 +1,68 @@
>> +Samsung's Multi Core Timer (MCT)
>> +
>> +The Samsung's Multi Core Timer (MCT) module includes two main blocks, the
>> +global timer and CPU local timers. The global timer is a 64-bit free running
>> +up-counter and can generate 4 interrupts when the counter reaches one of the
>> +four preset counter values. The CPU local timers are 32-bit free running
>> +down-counters and generate an interrupt when the counter expires. There is
>> +one CPU local timer instantiated in MCT for every CPU in the system.
>> +
>> +Required properties:
>> +
>> +- compatible: should be "samsung,exynos4210-mct".
>> +  (a) "samsung,exynos4210-mct", for mct compatible with Exynos4210 mct.
>> +  (b) "samsung,exynos4412-mct", for mct compatible with Exynos4412 mct.
>> +
>> +- reg: base address of the mct controller and length of the address space
>> +  it occupies.
>> +
>> +- interrupts: the list of interrupts generated by the controller. The following
>> +  should be the order of the interrupts specified. The local timer interrupts
>> +  should be specified after the four global timer interrupts have been
>> +  specified.
>> +
>> +     0: Global Timer Interrupt 0
>> +     1: Global Timer Interrupt 1
>> +     2: Global Timer Interrupt 2
>> +     3: Global Timer Interrupt 3
>> +     4: Local Timer Interrupt 0
>> +     5: Local Timer Interrupt 1
>> +     6: ..
>> +     7: ..
>> +     i: Local Timer Interrupt n
>> +
>> +Example 1: In this example, the system uses only the first global timer
>> +        interrupt generated by MCT and the remaining three global timer
>> +        interrupts are unused. Two local timer interrupts have been
>> +        specified.
>> +
>> +     mct at 10050000 {
>> +             compatible = "samsung,exynos4210-mct";
>> +             reg = <0x10050000 0x800>;
>> +             interrupts = <0 57 0>, <0 0 0>, <0 0 0>, <0 0 0>,
>> +                          <0 42 0>, <0 48 0>;
>
> Rather than padding the interrupts list with nonexistent interrupts, could you
> not use something like a #global-interrupts property?
>
> That way you don't have to list fake interrupts, you know exactly how many
> global interrupts to expect (so you can sanity-check the list without any
> special knowledge of the interrupt controller), and it's easier to support
> future revisions which could have more interrupts, in a backwards-compatible
> fashion.

Yes, you are right. I will do this change in the next version. Thanks
for your suggestion.

Thanks,
Thomas.

>
>> +     };
>> +
>> +Example 2: In this example, the MCT global and local timer interrupts are
>> +        connected to two seperate interrupt controllers. Hence, an
>> +        interrupt-map is created to map the interrupts to the respective
>> +        interrupt controllers.
>> +
>> +     mct at 101C0000 {
>> +             compatible = "samsung,exynos4210-mct";
>> +             reg = <0x101C0000 0x800>;
>> +             interrupt-controller;
>> +             #interrups-cells = <2>;
>> +             interrupt-parent = <&mct_map>;
>> +             interrupts = <0 0>, <1 0>, <2 0>, <3 0>,
>> +                          <4 0>, <5 0>;
>> +
>> +             mct_map: mct-map {
>> +                     #interrupt-cells = <2>;
>> +                     #address-cells = <0>;
>> +                     #size-cells = <0>;
>> +                     interrupt-map = <0x0 0 &combiner 23 3>,
>> +                                     <0x4 0 &gic 0 120 0>,
>> +                                     <0x5 0 &gic 0 121 0>;
>> +             };
>> +     };
>
>
> [...]
>
> Thanks,
> Mark.
>