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(h-178-174-189-39.A498.priv.bahnhof.se. [178.174.189.39]) by smtp.gmail.com with ESMTPSA id l5-20020a2e9085000000b002d7095bf808sm3636733ljg.128.2024.04.29.07.05.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Apr 2024 07:05:52 -0700 (PDT) From: Ulf Hansson To: "Rafael J . Wysocki" , Sudeep Holla , linux-pm@vger.kernel.org Cc: Lorenzo Pieralisi , Nikunj Kela , Prasad Sodagudi , Maulik Shah , Daniel Lezcano , Krzysztof Kozlowski , Ulf Hansson , linux-rt-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/6] pmdomain: core: Enable s2idle for CPU PM domains on PREEMPT_RT Date: Mon, 29 Apr 2024 16:05:26 +0200 Message-Id: <20240429140531.210576-2-ulf.hansson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240429140531.210576-1-ulf.hansson@linaro.org> References: <20240429140531.210576-1-ulf.hansson@linaro.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To allow a genpd provider for a CPU PM domain to enter a domain-idle-state during s2idle on a PREEMPT_RT based configuration, we can't use the regular spinlock, as they are turned into sleepable locks on PREEMPT_RT. To address this problem, let's convert into using the raw spinlock, but only for genpd providers that have the GENPD_FLAG_CPU_DOMAIN bit set. In this way, the lock can still be acquired/released in atomic context, which is needed in the idle-path for PREEMPT_RT. Do note that the genpd power-on/off notifiers may also be fired during s2idle, but these are already prepared for PREEMPT_RT as they are based on the raw notifiers. However, consumers of them may need to adopt accordingly to work properly on PREEMPT_RT. Signed-off-by: Ulf Hansson --- drivers/pmdomain/core.c | 47 ++++++++++++++++++++++++++++++++++++++- include/linux/pm_domain.h | 5 ++++- 2 files changed, 50 insertions(+), 2 deletions(-) diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c index 342779464c0d..abd3c069df8b 100644 --- a/drivers/pmdomain/core.c +++ b/drivers/pmdomain/core.c @@ -117,6 +117,48 @@ static const struct genpd_lock_ops genpd_spin_ops =3D { .unlock =3D genpd_unlock_spin, }; =20 +static void genpd_lock_raw_spin(struct generic_pm_domain *genpd) + __acquires(&genpd->raw_slock) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&genpd->raw_slock, flags); + genpd->raw_lock_flags =3D flags; +} + +static void genpd_lock_nested_raw_spin(struct generic_pm_domain *genpd, + int depth) + __acquires(&genpd->raw_slock) +{ + unsigned long flags; + + raw_spin_lock_irqsave_nested(&genpd->raw_slock, flags, depth); + genpd->raw_lock_flags =3D flags; +} + +static int genpd_lock_interruptible_raw_spin(struct generic_pm_domain *gen= pd) + __acquires(&genpd->raw_slock) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&genpd->raw_slock, flags); + genpd->raw_lock_flags =3D flags; + return 0; +} + +static void genpd_unlock_raw_spin(struct generic_pm_domain *genpd) + __releases(&genpd->raw_slock) +{ + raw_spin_unlock_irqrestore(&genpd->raw_slock, genpd->raw_lock_flags); +} + +static const struct genpd_lock_ops genpd_raw_spin_ops =3D { + .lock =3D genpd_lock_raw_spin, + .lock_nested =3D genpd_lock_nested_raw_spin, + .lock_interruptible =3D genpd_lock_interruptible_raw_spin, + .unlock =3D genpd_unlock_raw_spin, +}; + #define genpd_lock(p) p->lock_ops->lock(p) #define genpd_lock_nested(p, d) p->lock_ops->lock_nested(p, d) #define genpd_lock_interruptible(p) p->lock_ops->lock_interruptible(p) @@ -2069,7 +2111,10 @@ static void genpd_free_data(struct generic_pm_domain= *genpd) =20 static void genpd_lock_init(struct generic_pm_domain *genpd) { - if (genpd->flags & GENPD_FLAG_IRQ_SAFE) { + if (genpd->flags & GENPD_FLAG_CPU_DOMAIN) { + raw_spin_lock_init(&genpd->raw_slock); + genpd->lock_ops =3D &genpd_raw_spin_ops; + } else if (genpd->flags & GENPD_FLAG_IRQ_SAFE) { spin_lock_init(&genpd->slock); genpd->lock_ops =3D &genpd_spin_ops; } else { diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 772d3280d35f..670392ecd076 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -194,8 +194,11 @@ struct generic_pm_domain { spinlock_t slock; unsigned long lock_flags; }; + struct { + raw_spinlock_t raw_slock; + unsigned long raw_lock_flags; + }; }; - }; =20 static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *= pd) --=20 2.34.1