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From: Ulf Hansson <ulf.hansson@linaro.org>
To: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
	linux-pm@vger.kernel.org
Cc: Kevin Hilman <khilman@kernel.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Lina Iyer <lina.iyer@linaro.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>, Juri Lelli <juri.lelli@arm.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	linux-arm-kernel@lists.infradead.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org
Subject: [PATCH v6 11/25] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node
Date: Wed, 14 Mar 2018 17:58:21 +0100	[thread overview]
Message-ID: <1521046715-30683-12-git-send-email-ulf.hansson@linaro.org> (raw)
In-Reply-To: <1521046715-30683-1-git-send-email-ulf.hansson@linaro.org>

The CPU's idle state nodes are currently parsed at the common cpuidle DT
library, but also when initializing back-end data for the arch specific CPU
operations, as in the PSCI driver case.

To avoid open-coding, let's introduce of_get_cpu_state_node(), which takes
the device node for the CPU and the index to the requested idle state node,
as in-parameters. In case a corresponding idle state node is found, it
returns the node with the refcount incremented for it, else it returns
NULL.

Moreover, for ARM, there are two generic methods, to describe the CPU's
idle states, either via the flattened description through the
"cpu-idle-states" binding [1] or via the hierarchical layout, using the
"power-domains" and the "domain-idle-states" bindings [2]. Hence, let's
take both options into account.

[1]
Documentation/devicetree/bindings/arm/idle-states.txt
[2]
Documentation/devicetree/bindings/arm/psci.txt

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: Lina Iyer <ilina@codeaurora.org>
Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/of/base.c  | 35 +++++++++++++++++++++++++++++++++++
 include/linux/of.h |  8 ++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index ad28de9..88d36a3 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -338,6 +338,41 @@ int of_cpu_node_to_id(struct device_node *cpu_node)
 EXPORT_SYMBOL(of_cpu_node_to_id);
 
 /**
+ * of_get_cpu_state_node - Get CPU's idle state node at the given index
+ *
+ * @cpu_node: The device node for the CPU
+ * @index: The index in the list of the idle states
+ *
+ * Two generic methods can be used to describe a CPU's idle states, either via
+ * a flattened description through the "cpu-idle-states" binding or via the
+ * hierarchical layout, using the "power-domains" and the "domain-idle-states"
+ * bindings. This function check for both and returns the idle state node for
+ * the requested index.
+ *
+ * In case and idle state node is found at index, the refcount incremented for
+ * it, so call of_node_put() on it when done. Returns NULL if not found.
+ */
+struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
+					  int index)
+{
+	struct of_phandle_args args;
+	int err;
+
+	err = of_parse_phandle_with_args(cpu_node, "power-domains",
+					"#power-domain-cells", 0, &args);
+	if (!err) {
+		struct device_node *state_node =
+			of_parse_phandle(args.np, "domain-idle-states", index);
+
+		of_node_put(args.np);
+		return state_node;
+	}
+
+	return of_parse_phandle(cpu_node, "cpu-idle-states", index);
+}
+EXPORT_SYMBOL(of_get_cpu_state_node);
+
+/**
  * __of_device_is_compatible() - Check if the node matches given constraints
  * @device: pointer to node
  * @compat: required compatible string, NULL or "" for any match
diff --git a/include/linux/of.h b/include/linux/of.h
index da1ee95..288233c 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -348,6 +348,8 @@ extern const void *of_get_property(const struct device_node *node,
 				const char *name,
 				int *lenp);
 extern struct device_node *of_get_cpu_node(int cpu, unsigned int *thread);
+extern struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
+						 int index);
 #define for_each_property_of_node(dn, pp) \
 	for (pp = dn->properties; pp != NULL; pp = pp->next)
 
@@ -730,6 +732,12 @@ static inline struct device_node *of_get_cpu_node(int cpu,
 	return NULL;
 }
 
+static inline struct device_node *of_get_cpu_state_node(struct device_node *cpu_node,
+					int index)
+{
+	return NULL;
+}
+
 static inline int of_n_addr_cells(struct device_node *np)
 {
 	return 0;
-- 
2.7.4

  parent reply	other threads:[~2018-03-14 17:04 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-14 16:58 [PATCH v6 00/25] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 01/25] PM / Domains: Don't treat zero found compatible idle states as an error Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 02/25] PM / Domains: Deal with multiple states but no governor in genpd Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 03/25] PM / Domains: Add generic data pointer to genpd_power_state struct Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 04/25] PM / Domains: Add support for CPU devices to genpd Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 05/25] PM / Domains: Add helper functions to attach/detach CPUs to/from genpd Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 06/25] timer: Export next wakeup time of a CPU Ulf Hansson
2018-03-14 17:19   ` Mark Rutland
2018-03-14 16:58 ` [PATCH v6 07/25] PM / Domains: Add genpd governor for CPUs Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 08/25] PM / Domains: Extend genpd CPU governor to cope with QoS constraints Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 09/25] kernel/cpu_pm: Manage runtime PM in the idle path for CPUs Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 10/25] dt: psci: Update DT bindings to support hierarchical PSCI states Ulf Hansson
2018-03-14 16:58 ` Ulf Hansson [this message]
2018-03-18 12:51   ` [PATCH v6 11/25] of: base: Add of_get_cpu_state_node() to get idle states for a CPU node Rob Herring
2018-03-14 16:58 ` [PATCH v6 12/25] cpuidle: dt: Support hierarchical CPU idle states Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 13/25] drivers: firmware: psci: Split psci_dt_cpu_init_idle() Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 14/25] drivers: firmware: psci: Support hierarchical CPU idle states Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 15/25] drivers: firmware: psci: Simplify error path of psci_dt_init() Ulf Hansson
2018-03-14 17:25   ` Mark Rutland
2018-03-14 16:58 ` [PATCH v6 16/25] drivers: firmware: psci: Announce support for OS initiated suspend mode Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 17/25] drivers: firmware: psci: Prepare to use " Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 18/25] drivers: firmware: psci: Share a few internal PSCI functions Ulf Hansson
2018-03-14 17:30   ` Mark Rutland
2018-03-14 16:58 ` [PATCH v6 19/25] drivers: firmware: psci: Add support for PM domains using genpd Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 20/25] drivers: firmware: psci: Introduce psci_dt_topology_init() Ulf Hansson
2018-03-14 17:38   ` Mark Rutland
2018-04-10  7:19     ` Ulf Hansson
2018-04-10 11:10       ` Mark Rutland
2018-04-10 12:25         ` Ulf Hansson
2018-04-18 11:32           ` Mark Rutland
2018-03-14 16:58 ` [PATCH v6 21/25] drivers: firmware: psci: Try to attach CPU devices to their PM domains Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 22/25] drivers: firmware: psci: Deal with CPU hotplug when using OSI mode Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 23/25] MAINTAINERS: Update files for PSCI Ulf Hansson
2018-03-14 17:40   ` Mark Rutland
2018-03-14 16:58 ` [PATCH v6 24/25] arm64: kernel: Respect the hierarchical CPU topology in DT " Ulf Hansson
2018-03-14 16:58 ` [PATCH v6 25/25] arm64: dts: Convert to the hierarchical CPU topology layout for MSM8916 Ulf Hansson
2018-03-14 17:19 ` [PATCH v6 00/25] PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) Mark Rutland
2018-03-15 14:19   ` Ulf Hansson
2018-03-15 11:00 ` Geert Uytterhoeven
2018-03-15 13:14   ` Ulf Hansson

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