[PATCH 03/12] PM / Domains: Add notifier support for power domain transitions
Rafael J. Wysocki
rjw at rjwysocki.net
Mon Nov 3 06:54:05 PST 2014
CC: Kevin, Ulf, Geert.
On Monday, November 03, 2014 09:23:01 AM Amit Daniel Kachhap wrote:
> These power domain transition notifiers will assist in carrying
> out some activity associated with domain power on/off such as
> some registers which may lose its contents and need save/restore
> across domain power off/on.
>
> 4 type of notifications are added,
> GPD_OFF_PRE - GPD state before power off
> GPD_OFF_POST - GPD state after power off
> GPD_ON_PRE - GPD state before power off
> GPD_ON_POST - GPD state after power off
>
> 3 notfication API's are exported.
> 1) int genpd_register_notifier(struct notifier_block *nb, char *pd_name);
> 2) int genpd_unregister_notifier(struct notifier_block *nb, char *pd_name);
> 3) void genpd_invoke_transition_notifier(struct generic_pm_domain *genpd,
> enum gpd_on_off_state state);
>
> In this approach the notifiers are registered/unregistered with pd name.
> The actual invoking of the notfiers will be done by the platform implementing
> power domain enable/disable low level handlers according to the above
> defined notification types. This approach will considerably reduce the
> number of call to notifiers as compared to calling always from core
> powerdomain subsystem.
>
> Also the registered domain's will be managed inside a cache list and not
> part of the genpd structure. This will help in registration of notifiers from
> subsystems (such as clock) even when the PD subsystem is still not initialised.
> This list also filters out the unregistered pd's requesting notification.
>
> Cc: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
> Reviewed-by: Pankaj Dubey <pankaj.dubey at samsung.com>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel at samsung.com>
> ---
> drivers/base/power/domain.c | 112 ++++++++++++++++++++++++++++++++++++++++++-
> include/linux/pm_domain.h | 31 ++++++++++++
> 2 files changed, 142 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 40bc2f4..e05045e 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -46,10 +46,19 @@
> __retval; \
> })
>
> +struct cache_notify_domains {
> + char *name;
> + /* Node in the cache pm domain name list */
> + struct list_head cache_list_node;
> +};
> +
> static LIST_HEAD(gpd_list);
> static DEFINE_MUTEX(gpd_list_lock);
> +static LIST_HEAD(domain_notify_list);
> +static DEFINE_MUTEX(domain_notify_list_lock);
> +static BLOCKING_NOTIFIER_HEAD(genpd_transition_notifier_list);
>
> -static struct generic_pm_domain *pm_genpd_lookup_name(const char *domain_name)
> +struct generic_pm_domain *pm_genpd_lookup_name(const char *domain_name)
> {
> struct generic_pm_domain *genpd = NULL, *gpd;
>
> @@ -66,6 +75,7 @@ static struct generic_pm_domain *pm_genpd_lookup_name(const char *domain_name)
> mutex_unlock(&gpd_list_lock);
> return genpd;
> }
> +EXPORT_SYMBOL_GPL(pm_genpd_lookup_name);
>
> struct generic_pm_domain *dev_to_genpd(struct device *dev)
> {
> @@ -1908,6 +1918,106 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
> mutex_unlock(&gpd_list_lock);
> }
>
> +/**
> + * genpd_register_notifier - Register a PM domain for future notification.
> + * @nb: notification block containing notification handle.
> + * @pd_name: PM domain name.
> + */
> +int genpd_register_notifier(struct notifier_block *nb, char *pd_name)
> +{
> + int ret;
> + struct cache_notify_domains *entry;
> +
> + if (!pd_name)
> + return -EINVAL;
> +
> + /* Search if the pd is already registered */
> + mutex_lock(&domain_notify_list_lock);
> + list_for_each_entry(entry, &domain_notify_list, cache_list_node) {
> + if (!strcmp(entry->name, pd_name))
> + break;
> + }
> + mutex_unlock(&domain_notify_list_lock);
> +
> + if (entry) {
> + pr_err("%s: pd already exists\n", __func__);
> + return -EINVAL;
> + }
> +
> + entry = kzalloc(sizeof(*entry), GFP_KERNEL);
> + if (!entry)
> + return -ENOMEM;
> +
> + entry->name = pd_name;
> +
> + mutex_lock(&domain_notify_list_lock);
> + list_add(&entry->cache_list_node, &domain_notify_list);
> + mutex_unlock(&domain_notify_list_lock);
> + ret = blocking_notifier_chain_register(
> + &genpd_transition_notifier_list, nb);
> + return ret;
> +}
> +
> +/**
> + * genpd_unregister_notifier - Un-register a PM domain for future notification.
> + * @nb: notification block containing notification handle.
> + * @pd_name: PM domain name.
> + */
> +int genpd_unregister_notifier(struct notifier_block *nb, char *pd_name)
> +{
> + int ret;
> + struct cache_notify_domains *entry;
> +
> + mutex_lock(&domain_notify_list_lock);
> + list_for_each_entry(entry, &domain_notify_list, cache_list_node) {
> + if (!strcmp(entry->name, pd_name))
> + break;
> + }
> + if (!entry) {
> + mutex_unlock(&domain_notify_list_lock);
> + pr_err("%s: Invalid pd name\n", __func__);
> + return -EINVAL;
> + }
> + list_del(&entry->cache_list_node);
> + mutex_unlock(&domain_notify_list_lock);
> + ret = blocking_notifier_chain_unregister(
> + &genpd_transition_notifier_list, nb);
> + return ret;
> +}
> +
> +/**
> + * genpd_invoke_transition_notifier - Calls the matching notification handler.
> + * @genpd: generic power domain structure.
> + * @state: can be of type - GPD_OFF_PRE/GPD_OFF_POST/GPD_ON_PRE/GPD_ON_POST.
> + */
> +void genpd_invoke_transition_notifier(struct generic_pm_domain *genpd,
> + enum gpd_on_off_state state)
> +{
> + struct cache_notify_domains *entry;
> +
> + if (!genpd) {
> + pr_err("Invalid genpd parameter\n");
> + return;
> + }
> +
> + if (state != GPD_OFF_PRE || state != GPD_OFF_POST
> + || state != GPD_ON_PRE || state != GPD_ON_POST) {
> + pr_err("Invalid state parameter\n");
> + return;
> + }
> +
> + mutex_lock(&domain_notify_list_lock);
> + list_for_each_entry(entry, &domain_notify_list, cache_list_node) {
> + if (!strcmp(entry->name, genpd->name))
> + break;
> + }
> + mutex_unlock(&domain_notify_list_lock);
> + if (!entry) /* Simply ignore */
> + return;
> +
> + blocking_notifier_call_chain(&genpd_transition_notifier_list, state,
> + genpd);
> +}
> #ifdef CONFIG_PM_GENERIC_DOMAINS_OF
> /*
> * Device Tree based PM domain providers.
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 73e938b..659997f 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -25,6 +25,13 @@ enum gpd_status {
> GPD_STATE_POWER_OFF, /* PM domain is off */
> };
>
> +enum gpd_on_off_state {
> + GPD_OFF_PRE = 0, /* GPD state before power off */
> + GPD_OFF_POST, /* GPD state after power off */
> + GPD_ON_PRE, /* GPD state before power on */
> + GPD_ON_POST, /* GPD state after power on */
> +};
> +
> struct dev_power_governor {
> bool (*power_down_ok)(struct dev_pm_domain *domain);
> bool (*stop_ok)(struct device *dev);
> @@ -148,6 +155,12 @@ extern int pm_genpd_name_poweron(const char *domain_name);
>
> extern struct dev_power_governor simple_qos_governor;
> extern struct dev_power_governor pm_domain_always_on_gov;
> +
> +struct generic_pm_domain *pm_genpd_lookup_name(const char *domain_name);
> +int genpd_register_notifier(struct notifier_block *nb, char *pd_name);
> +int genpd_unregister_notifier(struct notifier_block *nb, char *pd_name);
> +void genpd_invoke_transition_notifier(struct generic_pm_domain *genpd,
> + enum gpd_on_off_state state);
> #else
>
> static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
> @@ -219,6 +232,24 @@ static inline int pm_genpd_name_poweron(const char *domain_name)
> {
> return -ENOSYS;
> }
> +static inline struct
> +generic_pm_domain *pm_genpd_lookup_name(const char *domain_name)
> +{
> + return NULL;
> +}
> +static inline int
> +genpd_register_notifier(struct notifier_block *nb, char *pd_name)
> +{
> + return 0;
> +}
> +static inline int
> +genpd_unregister_notifier(struct notifier_block *nb, char *pd_name)
> +{
> + return 0;
> +}
> +static inline void
> +genpd_invoke_transition_notifier(struct generic_pm_domain *genpd,
> + enum gpd_on_off_state state) { }
> #define simple_qos_governor NULL
> #define pm_domain_always_on_gov NULL
> #endif
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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