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From: Ulf Hansson <ulf.hansson@linaro.org>
To: Sudeep Holla <sudeep.holla@arm.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-arm-kernel@lists.infradead.org
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	"Raju P . L . S . S . S . N" <rplsssn@codeaurora.org>,
	Amit Kucheria <amit.kucheria@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	Niklas Cassel <niklas.cassel@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	Kevin Hilman <khilman@kernel.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Souvik Chakravarty <souvik.chakravarty@arm.com>,
	linux-pm@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Ulf Hansson <ulf.hansson@linaro.org>
Subject: [PATCH 15/18] drivers: firmware: psci: Support CPU hotplug for the hierarchical model
Date: Mon, 13 May 2019 21:22:57 +0200
Message-ID: <20190513192300.653-16-ulf.hansson@linaro.org> (raw)
Message-ID: <20190513192257.gYN1GaKGa6STsbEHb_GZERgof1tnoxlnjoNgUHqyP2E@z> (raw)
In-Reply-To: <20190513192300.653-1-ulf.hansson@linaro.org>

When the hierarchical CPU topology is used and when a CPU has been put
offline (hotplug), that same CPU prevents its PM domain and thus also
potential master PM domains, from being powered off. This is because genpd
observes the CPU's attached device as being active from a runtime PM point
of view.

To deal with this, let's decrease the runtime PM usage count by calling
pm_runtime_put_sync_suspend() of the attached struct device when putting
the CPU offline. Consequentially, we must then increase the runtime PM
usage count, while putting the CPU online again.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Changes:
	- Use get_logical_index() to find the CPU number.
	- Verify that a corresponding struct device* has been attached to the
	  PM domain before doing runtime PM refrence counting.
	- Clear the domain state when the CPU goes offline, to start fresh.
	- Move code to internal helper functions and move them inside
	  "ifdef CONFIG_CPU_IDLE.

---
 drivers/firmware/psci/psci.c | 47 +++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 2c4157d3a616..5ad93c3694b5 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -15,6 +15,7 @@
 
 #include <linux/acpi.h>
 #include <linux/arm-smccc.h>
+#include <linux/cpu.h>
 #include <linux/cpuidle.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
@@ -93,6 +94,9 @@ static u32 psci_function_id[PSCI_FN_MAX];
 static u32 psci_cpu_suspend_feature;
 static bool psci_system_reset2_supported;
 
+static void psci_cpuidle_cpu_off(void);
+static void psci_cpuidle_cpu_on(unsigned long cpuid);
+
 static inline bool psci_has_ext_power_state(void)
 {
 	return psci_cpu_suspend_feature &
@@ -188,6 +192,8 @@ static int psci_cpu_off(u32 state)
 	int err;
 	u32 fn;
 
+	psci_cpuidle_cpu_off();
+
 	fn = psci_function_id[PSCI_FN_CPU_OFF];
 	err = invoke_psci_fn(fn, state, 0, 0);
 	return psci_to_linux_errno(err);
@@ -200,7 +206,13 @@ static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 
 	fn = psci_function_id[PSCI_FN_CPU_ON];
 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
-	return psci_to_linux_errno(err);
+	err = psci_to_linux_errno(err);
+	if (err)
+		return err;
+
+	psci_cpuidle_cpu_on(cpuid);
+
+	return 0;
 }
 
 static int psci_migrate(unsigned long cpuid)
@@ -540,8 +552,41 @@ static int __init _psci_dt_topology_init(struct device_node *np)
 
 	return ret;
 }
+
+static void psci_cpuidle_cpu_off(void)
+{
+	struct device *dev = __this_cpu_read(psci_cpuidle_data.dev);
+
+	/*
+	 * Drop the runtime PM usage count if the CPU has been attached to a
+	 * CPU PM domain. This is needed to, for example, not prevent other
+	 * master domains in the hierarchy to remain powered on.
+	 */
+	if (dev)
+		pm_runtime_put_sync_suspend(dev);
+}
+
+static void psci_cpuidle_cpu_on(unsigned long cpuid)
+{
+	struct device *dev;
+	int cpu;
+
+	if (!psci_dt_topology)
+		return;
+
+	cpu = get_logical_index(cpuid);
+	if (cpu < 0)
+		return;
+
+	dev = per_cpu(psci_cpuidle_data.dev, cpu);
+	if (dev)
+		pm_runtime_get_sync(dev);
+}
+
 #else
 static inline int _psci_dt_topology_init(struct device_node *np) { return 0; }
+static void psci_cpuidle_cpu_off(void) {}
+static void psci_cpuidle_cpu_on(unsigned long cpuid) {}
 #endif
 
 static int psci_system_suspend(unsigned long unused)
-- 
2.17.1


  parent reply index

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13 19:22 [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Ulf Hansson
2019-05-13 19:22 ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 01/18] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-19 11:29   ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 02/18] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 03/18] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 04/18] ARM/ARM64: cpuidle: Let back-end init ops take the driver as input Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:00   ` Sudeep Holla
2019-06-10 10:20     ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 05/18] drivers: firmware: psci: Simplify state node parsing Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:01   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 06/18] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:03   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 07/18] drivers: firmware: psci: Prepare to use OS initiated suspend mode Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:17   ` Sudeep Holla
2019-06-10 10:21     ` Ulf Hansson
2019-06-10 10:42       ` Sudeep Holla
2019-07-16 14:53   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 08/18] drivers: firmware: psci: Prepare to support PM domains Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:21   ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 09/18] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-06-07 15:27   ` Sudeep Holla
2019-06-10 10:21     ` Ulf Hansson
2019-06-10 10:59       ` Sudeep Holla
2019-07-16 15:05   ` Sudeep Holla
2019-07-18 11:04     ` Ulf Hansson
2019-07-18 13:19       ` Sudeep Holla
2019-07-18 17:57         ` Lina Iyer
2019-07-19  9:45           ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 10/18] drivers: firmware: psci: Add hierarchical domain idle states converter Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-09 15:31   ` Lorenzo Pieralisi
2019-07-16  8:45     ` Ulf Hansson
2019-07-16 14:51       ` Lorenzo Pieralisi
2019-07-18 11:43         ` Ulf Hansson
2019-07-18 13:36           ` Lorenzo Pieralisi
2019-05-13 19:22 ` [PATCH 11/18] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 12/18] drivers: firmware: psci: Add a helper to attach a CPU to its PM domain Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 13/18] drivers: firmware: psci: Attach the CPU's device " Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 14/18] drivers: firmware: psci: Manage runtime PM in the idle path for CPUs Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-16 15:53   ` Lorenzo Pieralisi
2019-07-18 10:35     ` Ulf Hansson
2019-07-18 13:30       ` Lorenzo Pieralisi
2019-07-18 16:54         ` Ulf Hansson
2019-07-18 17:41           ` Lina Iyer
2019-07-18 21:49             ` Ulf Hansson
2019-07-19 10:02               ` Lorenzo Pieralisi
2019-05-13 19:22 ` Ulf Hansson [this message]
2019-05-13 19:22   ` [PATCH 15/18] drivers: firmware: psci: Support CPU hotplug for the hierarchical model Ulf Hansson
2019-06-07 15:31   ` Sudeep Holla
2019-06-10 10:21     ` Ulf Hansson
2019-06-10 11:02       ` Sudeep Holla
2019-05-13 19:22 ` [PATCH 16/18] arm64: kernel: Respect the hierarchical CPU topology in DT for PSCI Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-05-13 19:22 ` [PATCH 17/18] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2019-05-13 19:22   ` Ulf Hansson
2019-07-16 14:47   ` Sudeep Holla
2019-07-16 20:36     ` Lina Iyer
2019-07-17 17:18       ` Sudeep Holla
2019-05-13 19:23 ` [PATCH 18/18] arm64: dts: hikey: Convert to the hierarchical CPU topology layout Ulf Hansson
2019-05-13 19:23   ` Ulf Hansson
2019-07-16 14:47   ` Sudeep Holla
2019-07-18 10:48     ` Ulf Hansson
2019-07-18 13:11       ` Sudeep Holla
2019-05-14  8:08 ` [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Rafael J. Wysocki
2019-05-14  8:08   ` Rafael J. Wysocki
2019-05-14  8:58   ` Ulf Hansson
2019-05-14  8:58     ` Ulf Hansson
2019-06-07 15:42     ` Sudeep Holla
2019-06-07 19:34       ` Bjorn Andersson
2019-06-10 10:32         ` Sudeep Holla
2019-06-10 15:54           ` Ulf Hansson
2019-06-10 17:16             ` Lorenzo Pieralisi
2019-06-10 18:57               ` Ulf Hansson
2019-06-18 11:56                 ` Ulf Hansson
2019-06-07 11:19 ` Ulf Hansson

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