Re: [PATCH] ARM64: dts: rockchip: add core dtsi file for RK3399 SoCs

[Huang, Tao]

Hi, Mark:
On 2016å04æ25æ 18:47, Mark Rutland wrote:
> On Mon, Apr 25, 2016 at 06:19:28PM +0800, Huang, Tao wrote:
>> Hi, Mark:
>> On 2016å04æ25æ 18:05, Mark Rutland wrote:
>>> On Mon, Apr 25, 2016 at 05:48:51PM +0800, Huang, Tao wrote:
>>>> and pmu define as:
>>>>     pmu_a53 {
>>>>         compatible = "arm,cortex-a53-pmu";
>>>>         interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_LOW &part0>;
>>>>         interrupt-affinity = <&cpu_l0>,
>>>>                      <&cpu_l1>,
>>>>                      <&cpu_l2>,
>>>>                      <&cpu_l3>;
>>>>     };
>>>>
>>>>     pmu_a72 {
>>>>         compatible = "arm,cortex-a72-pmu", "arm,cortex-a57-pmu";
>>> That Cortex-A57 PMU fallback should just go. We already have Cortex-A72
>>> PMU support upstream, and I believe there are sufficient differences
>>> such that the Cortex-A72 PMU is not a strict superset of the Cortex-A57
>>> PMU.
>> As I say, I tested on v4.4, I don't back port
>> arch/arm64/kernel/perf_event.c, so I use "arm,cortex-a57-pmu". Upstream
>> will use "arm,cortex-a72-pmu" only.
>> BTW, I don't see any differences between A72/A57 in source code:
> The PMU name is exposed to userspace, so the user will be told they have
> a Cortex-A57 PMU, with all of the IMPLEMENTATION DEFINED events that
> implies.
>
> We don't handle those IMPLEMENTATION DEFINED events in the kernel, but
> for the sake of the userspace ABI, we should not expose the Cortex-A72
> PMU as a Cortex-A57 PMU.
>
> Given the code is otherwise identical, it should be relatively simple to
> backport the A72 support.
>
Understood, thank you!

Huang, Tao