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Date: Fri, 13 Nov 2015 13:56:08 +0800
From: Zhaoyang Huang <zhaoyang.huang@...aro.org>
To: Marc Titinger <mtitinger@...libre.com>
Cc: Lina Iyer <lina.iyer@...aro.org>, rjw@...ysocki.net,
khilman@...nel.org, Axel Haslam <ahaslam@...libre.com>,
Benoit Cousson <bcousson@...libre.com>,
linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
Marc Titinger <mtitinger+renesas@...libre.com>
Subject: Re: [RFC v3 2/7] PM / Domains: support idle-states as genpd multiple-state.
On 28 October 2015 at 01:40, Marc Titinger <mtitinger@...libre.com> wrote:
> From: Marc Titinger <mtitinger@...libre.com>
>
> This patch allows cluster-level idle-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 idle-states.
>
> This is a attempt to address device-retention states for devices that
> are not hooked to runtime-pm, but feature a retention state handled by
> the same firmware that handles idle-states. For instance a L2 caches.
>
> With Juno, in this example the idle-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@...libre.com>
> ---
> .../devicetree/bindings/power/power_domain.txt | 29 ++++++
> drivers/base/power/domain.c | 102 ++++++++++++++++++++-
> include/linux/pm_domain.h | 3 +
> 3 files changed, 131 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> index 025b5e7..2657e19 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.
>
> + - cpu-idle-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 : a device may register an intermediate c-state matching a memory
> + retention feature for instance.
> +
> Example:
>
> power: power-controller@...40000 {
> @@ -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>;
> + cpu-idle-states = <&CLUSTER_SLEEP_0>;
Should the "cpu_idle_states" be "domain-idle-states", which is
consistent to the following code.
> + };
> +
> + a53_pd: a53_pd@ {
> + /* will have a a53 platform ARM_PD_METHOD_OF_DECLARE*/
> + compatible = "arm,pd","arm,cortex-a53";
> + #power-domain-cells = <0>;
> + cpu-idle-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/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 6b2d771..8512e28 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1345,7 +1345,8 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
> else {
> dev_pm_qos_add_notifier(dev, &gpd_data->nb);
> atomic_inc(&genpd->usage_count);
> - printk("Add device %d\n", atomic_read(&genpd->usage_count));
> + dev_info(dev, "Add device %d\n",
> + atomic_read(&genpd->usage_count));
> }
> return ret;
> }
> @@ -1592,7 +1593,7 @@ static int state_cmp(const void *a, const void *b)
> int pm_genpd_insert_state(struct generic_pm_domain *genpd,
> const struct genpd_power_state *state)
> {
> - int ret = 0;
> + int i, ret = 0;
> int state_count = genpd->state_count;
>
> if (IS_ERR_OR_NULL(genpd) || (!state))
> @@ -1601,11 +1602,18 @@ int pm_genpd_insert_state(struct generic_pm_domain *genpd,
> if (state_count >= GENPD_POWER_STATES_MAX)
> ret = -ENOMEM;
>
> + /* Bail out, this state was already registered.*/
> + for (i = 0; i < state_count; i++)
> + if (!strncmp(state->name, genpd->states[i].name,
> + GENPD_MAX_NAME_SIZE))
> + return 0;
> +
> #ifdef CONFIG_PM_ADVANCED_DEBUG
> /* to save memory, Name allocation will happen if debug is enabled */
> genpd->states[state_count].name = kstrndup(state->name,
> GENPD_MAX_NAME_SIZE,
> GFP_KERNEL);
> +
> if (!genpd->states[state_count].name) {
> pr_err("%s Failed to allocate state '%s' name.\n",
> genpd->name, state->name);
> @@ -1963,6 +1971,93 @@ 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,
> + struct device_node *state_node)
> +{
> + int err = 0;
> + u32 latency;
> +
> + 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;
> +}
> +
> +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, "domain-idle-states", i);
> + if (!state_node)
> + break;
> +
> + err = dt_cpuidle_to_genpd_power_state(&genpd_state,
> + 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.
> @@ -1996,7 +2091,6 @@ int genpd_dev_pm_attach(struct device *dev)
> if (ret < 0) {
> if (ret != -ENOENT)
> return ret;
> -
> /*
> * Try legacy Samsung-specific bindings
> * (for backwards compatibility of DT ABI)
> @@ -2034,6 +2128,8 @@ int genpd_dev_pm_attach(struct device *dev)
> goto out;
> }
>
> + of_genpd_device_parse_states(pd_args.np, pd);
> +
> dev->pm_domain->detach = genpd_dev_pm_detach;
> dev->pm_domain->sync = genpd_dev_pm_sync;
> ret = genpd_poweron(pd);
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 24621be..48ab3b1 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -248,6 +248,9 @@ 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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