[PATCH v6 4/5] arm64: add support for ACPI Low Power Idle(LPI)
Sudeep Holla
sudeep.holla at arm.com
Mon Jun 27 02:50:39 PDT 2016
Hi, Daniel,
On 24/06/16 22:04, Daniel Lezcano wrote:
[...]
>>> +
>>> + psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
>>> + if (!psci_states)
>>> + return -ENOMEM;
>>> +
>>> + for (i = 0; i < count; i++) {
>>> + u32 state;
>>> +
>>> + lpi = &pr->power.lpi_states[i + 1];
>>> + state = lpi->address & 0xFFFFFFFF;
>
> Why is needed to mask 'address' ?
>
This is as per Section 3.1.1 FFH Usage in LPI state entry methods in [1]
[...]
>>> int psci_cpu_init_idle(unsigned int cpu)
>>> {
>>> struct device_node *cpu_node;
>>> int ret;
>>>
>>> + if (!acpi_disabled)
>>> + return psci_acpi_cpu_init_idle(cpu);
>
> Is it possible the case where there is information in both the DT and in
> ACPI ? So ACPI is enabled without idle information which is in the DT ?
>
No, as Rafael mentioned aready.
>>
>> Either you do this, or we have to add it somehow somewhere in
>> drivers/cpuidle to avoid duplicating it.
>>
>> @Daniel: do you have an opinion on this please ?
>
> Yes, this function should be added to avoid duplication.
>
So, I assume you are happy with the way it's handled in this patch ?
(I will rename the file as suggested by Lorenzo)
--
Regards,
Sudeep
[1]
http://infocenter.arm.com/help/topic/com.arm.doc.den0048a/DEN0048A_ARM_FFH_Specification.pdf
More information about the linux-arm-kernel
mailing list