Messages in this thread | | | Date | Thu, 8 Oct 2015 10:27:04 -0600 | From | Lina Iyer <> | Subject | Re: [RFC v2 3/6] PM / Domains: introduce power-states consistent with c-states. |
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On Tue, Oct 06 2015 at 08:27 -0600, Marc Titinger wrote: >This patch allows cluster-level C-states to being soaked in as generic >domain power states, in order for the domain governor to chose the most >efficient power state compatible with the device constraints. Similarly, >devices can register power-states into the cluster domain, in a manner >consistent with c-states. > A domain power state as depicted in the DT is no different than the CPU idle state. I think you can achieve this without adding another compatible - arm,power-state.
I think I am still at loss trying to understand why a device is populating the domain's power states.
>With Juno, in this example the c-state 'cluster-sleep-0 ' is known from >each cluster generic domain, as the deepest sate. > >cat /sys/kernel/debug/pm_genpd/* > > Domain State name Enter (ns) / Exit (ns) >------------------------------------------------------------- >a53_pd cluster-sleep-0 1500000 / 800000 >a57_pd cluster-sleep-0 1500000 / 800000 > > domain status pstate slaves > /device runtime status >----------------------------------------------------------------------- >a53_pd on > /devices/system/cpu/cpu0 active > /devices/system/cpu/cpu3 suspended > /devices/system/cpu/cpu4 suspended > /devices/system/cpu/cpu5 suspended > /devices/platform/D1 suspended >a57_pd cluster-sleep-0 > /devices/system/cpu/cpu1 suspended > /devices/system/cpu/cpu2 suspended > >Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com> >--- > .../devicetree/bindings/arm/idle-states.txt | 21 ++++- > .../devicetree/bindings/power/power_domain.txt | 29 ++++++ > arch/arm64/boot/dts/arm/juno.dts | 10 ++- > drivers/base/power/cpu-pd.c | 5 ++ > drivers/base/power/domain.c | 100 +++++++++++++++++++++ > include/linux/pm_domain.h | 3 + > 6 files changed, 163 insertions(+), 5 deletions(-) > >diff --git a/Documentation/devicetree/bindings/arm/idle-states.txt b/Documentation/devicetree/bindings/arm/idle-states.txt >index a8274ea..18fdeaf 100644 >--- a/Documentation/devicetree/bindings/arm/idle-states.txt >+++ b/Documentation/devicetree/bindings/arm/idle-states.txt >@@ -270,7 +270,8 @@ follows: > - compatible > Usage: Required > Value type: <stringlist> >- Definition: Must be "arm,idle-state". >+ Definition: Must be "arm,idle-state", >+ or "arm,power-state" (see section 5) > > - local-timer-stop > Usage: See definition >@@ -680,7 +681,23 @@ cpus { > }; > > =========================================== >-5 - References >+5 - power state >+=========================================== >+ >+Device in a generic power domain may expose an intermediate retention >+state that can be opted to by the domain governor when the last-man >+CPU is powered off. Those power-states will not be entered by the >+cpuidle.ops based on a state index, but instead can be elected by the >+domain governor and entered to by the generic domain. >+ Agreed.
>+ - compatible >+ Usage: Required >+ Value type: <stringlist> >+ Definition: Must be "arm,power-state". >+ >+ >+=========================================== >+6 - References > =========================================== > > [1] ARM Linux Kernel documentation - CPUs bindings >diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt >index 0f8ed37..d437385 100644 >--- a/Documentation/devicetree/bindings/power/power_domain.txt >+++ b/Documentation/devicetree/bindings/power/power_domain.txt >@@ -29,6 +29,16 @@ Optional properties: > specified by this binding. More details about power domain specifier are > available in the next section. > >+ - power-states : a phandle of an idle-state that shall be soaked into a >+ generic domain power state. >+ CPU domains: Deep c-states that match a cluster power-off can be delegated to the >+ generic power domain. Device other than CPUs may have register intermediate >+ power states in the same domain. The domain governor can do a good job in >+ electing a power state when the last cpu is powered off as devices in the >+ same genpd may register intermediate states. > Devices may enable a certain domain state, but should not be defining the domain state. The domain its state and the domain governor may choose to enter that state on a vote from its devices.
>+ Devices : a device may register an intermediate c-state matching a memory >+ retention feature for instance. > This point onwards is where I need clarity.
Thanks, Lina
>+ > Example: > > power: power-controller@12340000 { >@@ -55,6 +65,25 @@ Example 2: > #power-domain-cells = <1>; > }; > >+Example 3: >+ >+ pm-domains { >+ a57_pd: a57_pd@ { >+ /* will have a57 platform ARM_PD_METHOD_OF_DECLARE*/ >+ compatible = "arm,pd","arm,cortex-a57"; >+ #power-domain-cells = <0>; >+ power-states = <&CLUSTER_SLEEP_0>; >+ }; >+ >+ a53_pd: a53_pd@ { >+ /* will have a a53 platform ARM_PD_METHOD_OF_DECLARE*/ >+ compatible = "arm,pd","arm,cortex-a53"; >+ #power-domain-cells = <0>; >+ power-states = <&CLUSTER_SLEEP_0>; >+ }; >+ }; >+ >+ > The nodes above define two power controllers: 'parent' and 'child'. > Domains created by the 'child' power controller are subdomains of '0' power > domain provided by the 'parent' power controller. >diff --git a/arch/arm64/boot/dts/arm/juno.dts b/arch/arm64/boot/dts/arm/juno.dts >index 499f035..cadc5de 100644 >--- a/arch/arm64/boot/dts/arm/juno.dts >+++ b/arch/arm64/boot/dts/arm/juno.dts >@@ -47,7 +47,7 @@ > }; > > CLUSTER_SLEEP_0: cluster-sleep-0 { >- compatible = "arm,idle-state"; >+ compatible = "arm,idle-state","arm,power-state"; > arm,psci-suspend-param = <0x1010000>; > local-timer-stop; > entry-latency-us = <800>; >@@ -128,13 +128,17 @@ > pm-domains { > > a57_pd: a57_pd@ { >- compatible = "arm,pd"; >+ /* will have the a53 platform ARM_PD_METHOD_OF_DECLARE*/ >+ compatible = "arm,pd","arm,cortex-a57"; > #power-domain-cells = <0>; >+ power-states = <&CLUSTER_SLEEP_0>; > }; > > a53_pd: a53_pd@ { >- compatible = "arm,pd"; >+ /* will have the a53 platform ARM_PD_METHOD_OF_DECLARE*/ >+ compatible = "arm,pd","arm,cortex-a57"; > #power-domain-cells = <0>; >+ power-states = <&CLUSTER_SLEEP_0>; > }; > }; > >diff --git a/drivers/base/power/cpu-pd.c b/drivers/base/power/cpu-pd.c >index 5f30025..3c4cb12 100644 >--- a/drivers/base/power/cpu-pd.c >+++ b/drivers/base/power/cpu-pd.c >@@ -163,6 +163,11 @@ int of_register_cpu_pm_domain(struct device_node *dn, > pm_genpd_init(pd->genpd, &simple_qos_governor, false); > of_genpd_add_provider_simple(dn, pd->genpd); > >+ /* if a cpuidle-state is declared in this domain node, it will >+ * be the domain's job to enter/exit this state, if the device >+ * subdomain constraints are compatible */ >+ of_genpd_device_parse_states(dn, &pd->genpd); >+ > /* Attach the CPUs to the CPU PM domain */ > return of_pm_domain_attach_cpus(); > } >diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >index e5f4c00b..1ca28a2 100644 >--- a/drivers/base/power/domain.c >+++ b/drivers/base/power/domain.c >@@ -2156,6 +2156,104 @@ static void genpd_dev_pm_sync(struct device *dev) > genpd_queue_power_off_work(pd); > } > >+static int dt_cpuidle_to_genpd_power_state(struct genpd_power_state >+ *genpd_state, >+ const struct of_device_id *matches, >+ struct device_node *state_node) >+{ >+ const struct of_device_id *match_id; >+ int err = 0; >+ u32 latency; >+ >+ match_id = of_match_node(matches, state_node); >+ if (!match_id) >+ return -ENODEV; >+ >+ err = of_property_read_u32(state_node, "wakeup-latency-us", &latency); >+ if (err) { >+ u32 entry_latency, exit_latency; >+ >+ err = of_property_read_u32(state_node, "entry-latency-us", >+ &entry_latency); >+ if (err) { >+ pr_debug(" * %s missing entry-latency-us property\n", >+ state_node->full_name); >+ return -EINVAL; >+ } >+ >+ err = of_property_read_u32(state_node, "exit-latency-us", >+ &exit_latency); >+ if (err) { >+ pr_debug(" * %s missing exit-latency-us property\n", >+ state_node->full_name); >+ return -EINVAL; >+ } >+ /* >+ * If wakeup-latency-us is missing, default to entry+exit >+ * latencies as defined in idle states bindings >+ */ >+ latency = entry_latency + exit_latency; >+ } >+ >+ genpd_state->power_on_latency_ns = 1000 * latency; >+ >+ err = of_property_read_u32(state_node, "entry-latency-us", &latency); >+ if (err) { >+ pr_debug(" * %s missing min-residency-us property\n", >+ state_node->full_name); >+ return -EINVAL; >+ } >+ >+ genpd_state->power_off_latency_ns = 1000 * latency; >+ >+ return 0; >+} >+ >+static const struct of_device_id power_state_match[] = { >+ {.compatible = "arm,power-state", >+ }, >+}; >+ >+int of_genpd_device_parse_states(struct device_node *np, >+ struct generic_pm_domain *genpd) >+{ >+ struct device_node *state_node; >+ int i, err = 0; >+ >+ for (i = 0;; i++) { >+ struct genpd_power_state genpd_state; >+ >+ state_node = of_parse_phandle(np, "power-states", i); >+ if (!state_node) >+ break; >+ >+ err = dt_cpuidle_to_genpd_power_state(&genpd_state, >+ power_state_match, >+ state_node); >+ if (err) { >+ pr_err >+ ("Parsing idle state node %s failed with err %d\n", >+ state_node->full_name, err); >+ err = -EINVAL; >+ break; >+ } >+#ifdef CONFIG_PM_ADVANCED_DEBUG >+ genpd_state.name = kstrndup(state_node->name, >+ GENPD_MAX_NAME_SIZE, GFP_KERNEL); >+ if (!genpd_state.name) >+ err = -ENOMEM; >+#endif >+ of_node_put(state_node); >+ err = pm_genpd_insert_state(genpd, &genpd_state); >+ if (err) >+ break; >+#ifdef CONFIG_PM_ADVANCED_DEBUG >+ kfree(genpd_state.name); >+#endif >+ } >+ return err; >+} >+ > /** > * genpd_dev_pm_attach - Attach a device to its PM domain using DT. > * @dev: Device to attach. >@@ -2224,6 +2322,8 @@ int genpd_dev_pm_attach(struct device *dev) > return ret; > } > >+ of_genpd_device_parse_states(dev->of_node, pd); >+ > dev->pm_domain->detach = genpd_dev_pm_detach; > dev->pm_domain->sync = genpd_dev_pm_sync; > pm_genpd_poweron(pd); >diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h >index 8a4eab0..791a8ac 100644 >--- a/include/linux/pm_domain.h >+++ b/include/linux/pm_domain.h >@@ -302,6 +302,9 @@ struct generic_pm_domain *__of_genpd_xlate_onecell( > struct of_phandle_args *genpdspec, > void *data); > >+int of_genpd_device_parse_states(struct device_node *np, >+ struct generic_pm_domain *genpd); >+ > int genpd_dev_pm_attach(struct device *dev); > #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */ > static inline int __of_genpd_add_provider(struct device_node *np, >-- >1.9.1 >
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