cpuidle: psci: Add a helper to attach a CPU to its PM domain

Introduce a PSCI DT helper function, psci_dt_attach_cpu(), which takes a
CPU number as an in-parameter and tries to attach the CPU's struct device
to its corresponding PM domain.

Let's makes use of dev_pm_domain_attach_by_name(), as it allows us to
specify "psci" as the "name" of the PM domain to attach to. Additionally,
let's also prepare the attached device to be power managed via runtime PM.

Note that, the implementation of the new helper function is in a new
separate c-file, which may seems a bit too much at this point. However,
subsequent changes that implements the remaining part of the PM domain
support for cpuidle-psci, helps to justify this split.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>

diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index ee70d5cc5b996b446bb130dd8ee47dae63c4c23d..cc8c769d7fa9a2a57e319beb3be45c631a275c73 100644 (file)
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -21,7 +21,9 @@ obj-$(CONFIG_ARM_U8500_CPUIDLE)         += cpuidle-ux500.o
 obj-$(CONFIG_ARM_AT91_CPUIDLE)          += cpuidle-at91.o
 obj-$(CONFIG_ARM_EXYNOS_CPUIDLE)        += cpuidle-exynos.o
 obj-$(CONFIG_ARM_CPUIDLE)              += cpuidle-arm.o
-obj-$(CONFIG_ARM_PSCI_CPUIDLE)         += cpuidle-psci.o
+obj-$(CONFIG_ARM_PSCI_CPUIDLE)         += cpuidle_psci.o
+cpuidle_psci-y                         := cpuidle-psci.o
+cpuidle_psci-$(CONFIG_PM_GENERIC_DOMAINS_OF) += cpuidle-psci-domain.o
 
 ###############################################################################
 # MIPS drivers

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
new file mode 100644 (file)
index 0000000..87f881c
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PM domains for CPUs via genpd - managed by cpuidle-psci.
+ *
+ * Copyright (C) 2019 Linaro Ltd.
+ * Author: Ulf Hansson <ulf.hansson@linaro.org>
+ *
+ */
+
+#include <linux/cpu.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/pm_domain.h>
+#include <linux/pm_runtime.h>
+
+#include "cpuidle-psci.h"
+
+struct device __init *psci_dt_attach_cpu(int cpu)
+{
+       struct device *dev;
+
+       dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), "psci");
+       if (IS_ERR_OR_NULL(dev))
+               return dev;
+
+       pm_runtime_irq_safe(dev);
+       if (cpu_online(cpu))
+               pm_runtime_get_sync(dev);
+
+       return dev;
+}

diff --git a/drivers/cpuidle/cpuidle-psci.h b/drivers/cpuidle/cpuidle-psci.h
new file mode 100644 (file)
index 0000000..8609482
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-psci.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __CPUIDLE_PSCI_H
+#define __CPUIDLE_PSCI_H
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+struct device __init *psci_dt_attach_cpu(int cpu);
+#else
+static inline struct device __init *psci_dt_attach_cpu(int cpu) { return NULL; }
+#endif
+
+#endif /* __CPUIDLE_PSCI_H */