Thanks Pete for your patch!
On Fri, 2025-06-27 at 14:08 +0100, Peter Griffin wrote:
> Register cpu pm notifiers for gs101 which call the
> gs101_cpu_pmu_online/offline callbacks which in turn program the ACPM
> hint. This is required to actually enter the C2 idle state.
>
> A couple of corner cases are handled, namely when the system is rebooting
> or suspending we ignore the request. Additionally the request is ignored if
> the CPU is in CPU hot plug. Some common code is refactored so that it can
> be called from both the CPU hot plug callback and CPU PM notifier taking
> into account that CPU PM notifiers are called with IRQs disabled whereas
> CPU hotplug callbacks aren't.
>
> Note: this patch has a runtime dependency on adding 'local-timer-stop' dt
> property to the CPU nodes. This informs the time framework to switch to a
> broadcast timer as the local timer will be shutdown. Without that DT
> property specified the system hangs in early boot with this patch applied.
>
> Signed-off-by: Peter Griffin <peter.griffin@xxxxxxxxxx>
With this applied, I see the following during boot:
[ 1.841304][ T0] =============================
[ 1.841422][ T0] [ BUG: Invalid wait context ]
[ 1.841550][ T0] 6.16.0-rc4-next-20250702+ #54 Tainted: G U T
[ 1.841727][ T0] -----------------------------
[ 1.841844][ T0] swapper/0/0 is trying to lock:
[ 1.841965][ T0] ffff000800ee84b8 (&pmu_context->cpupm_lock){....}-{3:3}
[ 1.842001][ T0] , at: gs101_cpu_pm_notify_callback+0x48/0x100
[ 1.842309][ T0] other info that might help us debug this:
[ 1.842613][ T0] context-{5:5}
[ 1.842987][ T0] 1 lock held by swapper/0/0:
[ 1.843442][ T0] #0:
[ 1.843859][ T0] ffffafe9d8f1f100
[ 1.844282][ T0] (
[ 1.844618][ T0] cpu_pm_notifier.lock
[ 1.844980][ T0] ){....}-{2:2}, at: cpu_pm_enter+0x30/0x88
[ 1.845340][ T0] stack backtrace:
[ 1.845855][ T0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G U T 6.16.0-rc4-next-20250702+ #54 PREEMPT
[ 1.845878][ T0] Tainted: [U]=USER, [T]=RANDSTRUCT
[ 1.845884][ T0] Hardware name: Oriole (DT)
[ 1.845897][ T0] Call trace:
[ 1.845909][ T0] show_stack+0x24/0x38 (C)
[ 1.845934][ T0] dump_stack_lvl+0x40/0xc0
[ 1.845949][ T0] dump_stack+0x18/0x24
[ 1.845956][ T0] __lock_acquire+0xc68/0xd90
[ 1.845976][ T0] lock_acquire+0x14c/0x2b8
[ 1.845985][ T0] _raw_spin_lock+0x54/0x78
[ 1.846011][ T0] gs101_cpu_pm_notify_callback+0x48/0x100
[ 1.846021][ T0] notifier_call_chain+0xb0/0x198
[ 1.846046][ T0] raw_notifier_call_chain_robust+0x50/0xb0
[ 1.846053][ T0] cpu_pm_enter+0x4c/0x88
[ 1.846063][ T0] psci_enter_idle_state+0x2c/0x70
[ 1.846078][ T0] cpuidle_enter_state+0x14c/0x4c0
[ 1.846097][ T0] cpuidle_enter+0x44/0x68
[ 1.846121][ T0] do_idle+0x1f0/0x2a8
[ 1.846142][ T0] cpu_startup_entry+0x40/0x50
[ 1.846152][ T0] rest_init+0x1c4/0x1d0
[ 1.846161][ T0] start_kernel+0x358/0x438
[ 1.846181][ T0] __primary_switched+0x88/0x98
>
> [...]
>
> @@ -444,6 +586,18 @@ static int exynos_pmu_probe(struct platform_device *pdev)
> */
> dev_warn(&pdev->dev, "pmu-intr-gen syscon unavailable\n");
> } else {
> + pmu_context->hotplug_ing =
> + devm_kmalloc_array(dev, num_possible_cpus(),
> + sizeof(bool), GFP_KERNEL);
I haven't done a full review, but sizeof(bool) should be rewritten as
sizeof(*pmu_context->hotplug_ing)
> [...]
>
> @@ -471,10 +628,32 @@ static int exynos_pmu_probe(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +static int exynos_cpupm_suspend_noirq(struct device *dev)
> +{
> + atomic_set(&pmu_context->sys_suspended, 1);
> + return 0;
> +}
> +
> +static int exynos_cpupm_resume_noirq(struct device *dev)
> +{
> + atomic_set(&pmu_context->sys_suspended, 0);
> + return 0;
> +}
> +
> +static const struct dev_pm_ops cpupm_pm_ops = {
> + .suspend_noirq = exynos_cpupm_suspend_noirq,
> + .resume_noirq = exynos_cpupm_resume_noirq,
> +};
> +#endif
> +
> static struct platform_driver exynos_pmu_driver = {
> .driver = {
> .name = "exynos-pmu",
> .of_match_table = exynos_pmu_of_device_ids,
> +#ifdef CONFIG_PM_SLEEP
> + .pm = &cpupm_pm_ops,
> +#endif
This can use pm_sleep_ptr() instead to avoid the ifdef.
Cheers,
Andre'
