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SubjectRe: [PATCH v6 1/5] cpuidle: qcom_spm: Detach state machine from main SPM handling
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Il 21/06/21 23:08, Stephan Gerhold ha scritto:
> On Mon, Jun 21, 2021 at 08:10:12PM +0200, AngeloGioacchino Del Regno wrote:
>> In commit a871be6b8eee ("cpuidle: Convert Qualcomm SPM driver to a generic
>> CPUidle driver") the SPM driver has been converted to a
>> generic CPUidle driver: that was mainly made to simplify the
>> driver and that was a great accomplishment;
>> Though, it was ignored that the SPM driver is not used only
>> on the ARM architecture.
>>
>
> I don't really understand why you insist on writing that I deliberately
> "ignored" your use case when converting the driver. This is not true.
> Perhaps that's not actually what you meant but that's how it sounds to
> me.
>

So much noise for one single word. I will change it since it seems to be
that much of a deal, and I'm sorry if that hurt you in any way.

For the records, though, I really don't see anything offensive in that,
and anyway I didn't mean to be offensive in any way.

>> In preparation for the enablement of SPM features on AArch64/ARM64,
>> split the cpuidle-qcom-spm driver in two: the CPUIdle related
>> state machine (currently used only on ARM SoCs) stays there, while
>> the SPM communication handling lands back in soc/qcom/spm.c and
>> also making sure to not discard the simplifications that were
>> introduced in the aforementioned commit.
>>
>> Since now the "two drivers" are split, the SCM dependency in the
>> main SPM handling is gone and for this reason it was also possible
>> to move the SPM initialization early: this will also make sure that
>> whenever the SAW CPUIdle driver is getting initialized, the SPM
>> driver will be ready to do the job.
>>
>> Please note that the anticipation of the SPM initialization was
>> also done to optimize the boot times on platforms that have their
>> CPU/L2 idle states managed by other means (such as PSCI), while
>> needing SAW initialization for other purposes, like AVS control.
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
>> ---
>> drivers/cpuidle/Kconfig.arm | 1 +
>> drivers/cpuidle/cpuidle-qcom-spm.c | 324 +++++++----------------------
>> drivers/soc/qcom/Kconfig | 9 +
>> drivers/soc/qcom/Makefile | 1 +
>> drivers/soc/qcom/spm.c | 198 ++++++++++++++++++
>> include/soc/qcom/spm.h | 41 ++++
>> 6 files changed, 325 insertions(+), 249 deletions(-)
>> create mode 100644 drivers/soc/qcom/spm.c
>> create mode 100644 include/soc/qcom/spm.h
>>
>> diff --git a/drivers/cpuidle/cpuidle-qcom-spm.c b/drivers/cpuidle/cpuidle-qcom-spm.c
>> index adf91a6e4d7d..091453135ea6 100644
>> --- a/drivers/cpuidle/cpuidle-qcom-spm.c
>> +++ b/drivers/cpuidle/cpuidle-qcom-spm.c
>> [...]
>> +static int spm_cpuidle_register(int cpu)
>> {
>> + struct platform_device *pdev = NULL;
>> + struct device_node *cpu_node, *saw_node;
>> + struct cpuidle_qcom_spm_data data = {
>> + .cpuidle_driver = {
>> + .name = "qcom_spm",
>> + .owner = THIS_MODULE,
>> + .cpumask = (struct cpumask *)cpumask_of(cpu),
>> + .states[0] = {
>> + .enter = spm_enter_idle_state,
>> + .exit_latency = 1,
>> + .target_residency = 1,
>> + .power_usage = UINT_MAX,
>> + .name = "WFI",
>> + .desc = "ARM WFI",
>> + }
>> + }
>> + };
>
> The stack is gone after the function returns.
>

Argh, I wrongly assumed that cpuidle was actually copying this locally.
Okay, let's see what else looking clean I can come up with.

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