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Message-ID: <CAKddAkAOUJSnM=Px-YO=U6pis_7mODHZbmYqcgEzXikriqYvXQ@mail.gmail.com>
Date: Wed, 14 Aug 2024 09:56:22 +0800
From: Nick Hu <nick.hu@...ive.com>
To: Anup Patel <anup@...infault.org>
Cc: rafael@...nel.org, daniel.lezcano@...aro.org, paul.walmsley@...ive.com,
palmer@...belt.com, aou@...s.berkeley.edu, linux-pm@...r.kernel.org,
linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
greentime.hu@...ive.com, zong.li@...ive.com,
Anup Patel <apatel@...tanamicro.com>
Subject: Re: [PATCH] cpuidle: riscv-sbi: Allow cpuidle pd used by other devices
Hi Anup
Thanks for your feedback!
On Tue, Aug 13, 2024 at 8:25 PM Anup Patel <anup@...infault.org> wrote:
>
> On Tue, Aug 13, 2024 at 1:43 PM Nick Hu <nick.hu@...ive.com> wrote:
> >
> > To prevent the probe of consumer devices being deferred, create the
> > platform devices for each pd node under '/cpus/power-domains' and move the
> > driver initailization to the arch_initcall.
>
> To prevent the probe deferral of consumer devices, you can simply use
> fwnode_dev_initialized() instead of creating a dummy platform device.
>
You are right. I'll remove the dummy platform device.
If the fwnode_dev_initialized() was done before
fw_devlink_create_devlink(), the link will be dropped.
The fwnode_dev_initialized() is already included in the
of_genpd_add_provider_simple() and If the fwnode_dev_initialized()
was done before fw_devlink_create_devlink(), the link will be dropped.
so I think we only need to move the driver initialization
to the arch_initcall.
Thanks!
> > The consumer devices that inside the cpu/cluster power domain may register
> > the genpd notifier where their power domains are point to the pd nodes
> > under '/cpus/power-domains'. If the cpuidle.off==1, the genpd notifier
> > will fail due to sbi_cpuidle_pd_allow_domain_state is not set. We also
> > need the sbi_cpuidle_cpuhp_up/down to invoke the callbacks. Therefore,
> > add a cpuidle_disabled() check before registering the cpuidle driver to
> > address the issue.
>
> I think dealing with cpuidle.off==1 case should be a separate patch.
>
Sure, I'll update it in the next patch
> >
> > Signed-off-by: Nick Hu <nick.hu@...ive.com>
> > Link: https://lore.kernel.org/lkml/20240226065113.1690534-1-nick.hu@sifive.com/
> > Suggested-by: Anup Patel <apatel@...tanamicro.com>
> > ---
> > drivers/cpuidle/cpuidle-riscv-sbi.c | 24 +++++++++++++++++++++---
> > 1 file changed, 21 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
> > index a6e123dfe394..d6b01fc64f94 100644
> > --- a/drivers/cpuidle/cpuidle-riscv-sbi.c
> > +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
> > @@ -16,6 +16,7 @@
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > #include <linux/of.h>
> > +#include <linux/of_platform.h>
> > #include <linux/slab.h>
> > #include <linux/platform_device.h>
> > #include <linux/pm_domain.h>
> > @@ -25,6 +26,7 @@
> > #include <asm/smp.h>
> > #include <asm/suspend.h>
> >
> > +#include "cpuidle.h"
> > #include "dt_idle_states.h"
> > #include "dt_idle_genpd.h"
> >
> > @@ -336,6 +338,9 @@ static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
> > return ret;
> > }
> >
> > + if (cpuidle_disabled())
> > + return 0;
> > +
> > ret = cpuidle_register(drv, NULL);
> > if (ret)
> > goto deinit;
> > @@ -380,20 +385,26 @@ static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
> > struct sbi_pd_provider {
> > struct list_head link;
> > struct device_node *node;
> > + struct platform_device *pdev;
> > };
> >
> > static LIST_HEAD(sbi_pd_providers);
> >
> > static int sbi_pd_init(struct device_node *np)
> > {
> > + struct platform_device *pdev;
> > struct generic_pm_domain *pd;
> > struct sbi_pd_provider *pd_provider;
> > struct dev_power_governor *pd_gov;
> > int ret = -ENOMEM;
> >
> > + pdev = of_platform_device_create(np, np->name, NULL);
> > + if (!pdev)
> > + goto out;
> > +
> > pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
> > if (!pd)
> > - goto out;
> > + goto free_pdev;
> >
> > pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
> > if (!pd_provider)
> > @@ -419,6 +430,7 @@ static int sbi_pd_init(struct device_node *np)
> > goto remove_pd;
> >
> > pd_provider->node = of_node_get(np);
> > + pd_provider->pdev = pdev;
> > list_add(&pd_provider->link, &sbi_pd_providers);
> >
> > pr_debug("init PM domain %s\n", pd->name);
> > @@ -430,6 +442,8 @@ static int sbi_pd_init(struct device_node *np)
> > kfree(pd_provider);
> > free_pd:
> > dt_idle_pd_free(pd);
> > +free_pdev:
> > + of_platform_device_destroy(&pdev->dev, NULL);
> > out:
> > pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
> > return ret;
> > @@ -447,6 +461,7 @@ static void sbi_pd_remove(void)
> > if (!IS_ERR(genpd))
> > kfree(genpd);
> >
> > + of_platform_device_destroy(&pd_provider->pdev->dev, NULL);
> > of_node_put(pd_provider->node);
> > list_del(&pd_provider->link);
> > kfree(pd_provider);
> > @@ -548,7 +563,10 @@ static int sbi_cpuidle_probe(struct platform_device *pdev)
> > /* Setup CPU hotplut notifiers */
> > sbi_idle_init_cpuhp();
> >
> > - pr_info("idle driver registered for all CPUs\n");
> > + if (cpuidle_disabled())
> > + pr_info("cpuidle is disabled\n");
> > + else
> > + pr_info("idle driver registered for all CPUs\n");
> >
> > return 0;
> >
> > @@ -592,4 +610,4 @@ static int __init sbi_cpuidle_init(void)
> >
> > return 0;
> > }
> > -device_initcall(sbi_cpuidle_init);
> > +arch_initcall(sbi_cpuidle_init);
> > --
> > 2.34.1
> >
>
> Regards,
> Anup
Regards,
Nick
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