Hi Tomasz, thank you for posting this series. I would like to use the DT bindings for power domains in the bindings for C-states on ARM: http://comments.gmane.org/gmane.linux.power-management.general/41012 and in particular link a given C-state to a given power domain so that the kernel will have a way to actually check what devices are lost upon C-state entry (and for devices I also mean CPU peripheral like PMUs, GIC CPU IF, caches and possibly cpus, all of them already represented with DT nodes). I have a remark: - Can we group device nodes under a single power-domain-parent so that all devices defined under that parent won't have to re-define a power-domain property (a property like interrupt-parent, so to speak) What do you think ? Thanks, Lorenzo On Sat, Jan 11, 2014 at 07:42:46PM +0000, Tomasz Figa wrote: > This patch introduces generic code to perform power domain look-up using > device tree and automatically bind devices to their power domains. > Generic device tree binding is introduced to specify power domains of > devices in their device tree nodes. > > Backwards compatibility with legacy Samsung-specific power domain > bindings is provided, but for now the new code is not compiled when > CONFIG_ARCH_EXYNOS is selected to avoid collision with legacy code. This > will change as soon as Exynos power domain code gets converted to use > the generic framework in further patch. > > Signed-off-by: Tomasz Figa <tomasz.figa@xxxxxxxxx> > --- > .../devicetree/bindings/power/power_domain.txt | 51 ++++ > drivers/base/power/domain.c | 339 +++++++++++++++++++++ > include/linux/pm_domain.h | 34 +++ > kernel/power/Kconfig | 4 + > 4 files changed, 428 insertions(+) > create mode 100644 Documentation/devicetree/bindings/power/power_domain.txt > > diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt > new file mode 100644 > index 0000000..93be5d9 > --- /dev/null > +++ b/Documentation/devicetree/bindings/power/power_domain.txt > @@ -0,0 +1,51 @@ > +* Generic power domains > + > +System on chip designs are often divided into multiple power domains that > +can be used for power gating of selected IP blocks for power saving by > +reduced leakage current. > + > +This device tree binding can be used to bind power domain consumer devices > +with their power domains provided by power domain providers. A power domain > +provider can be represented by any node in the device tree and can provide > +one or more power domains. A consumer node can refer to the provider by > +a phandle and a set of phandle arguments (so called power domain specifier) > +of length specified by #power-domain-cells property in the power domain > +provider node. > + > +==Power domain providers== > + > +Required properties: > + - #power-domain-cells : Number of cells in a power domain specifier; > + Typically 0 for nodes representing a single power domain and 1 for nodes > + providing multiple power domains (e.g. power controllers), but can be > + any value as specified by device tree binding documentation of particular > + provider. > + > +Example: > + > + power: power-controller@12340000 { > + compatible = "foo,power-controller"; > + reg = <0x12340000 0x1000>; > + #power-domain-cells = <1>; > + }; > + > +The node above defines a power controller that is a power domain provider > +and expects one cell as its phandle argument. > + > +==Power domain consumers== > + > +Required properties: > + - power-domain : A phandle and power domain specifier as defined by bindings > + of power controller specified by phandle. > + > +Example: > + > + leaky-device@12350000 { > + compatible = "foo,i-leak-current"; > + reg = <0x12350000 0x1000>; > + power-domain = <&power 0>; > + }; > + > +The node above defines a typical power domain consumer device, which is located > +inside power domain with index 0 of power controller represented by node with > +label "power". > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > index bfb8955..6d47498 100644 > --- a/drivers/base/power/domain.c > +++ b/drivers/base/power/domain.c > @@ -3,12 +3,16 @@ > * > * Copyright (C) 2011 Rafael J. Wysocki <rjw@xxxxxxx>, Renesas Electronics Corp. > * > + * Support for Device Tree based power domain providers: > + * Copyright (C) 2014 Tomasz Figa <tomasz.figa@xxxxxxxxx> > + * > * This file is released under the GPLv2. > */ > > #include <linux/init.h> > #include <linux/kernel.h> > #include <linux/io.h> > +#include <linux/platform_device.h> > #include <linux/pm_runtime.h> > #include <linux/pm_domain.h> > #include <linux/pm_qos.h> > @@ -2177,3 +2181,338 @@ void pm_genpd_init(struct generic_pm_domain *genpd, > list_add(&genpd->gpd_list_node, &gpd_list); > mutex_unlock(&gpd_list_lock); > } > + > +#ifdef CONFIG_PM_GENERIC_DOMAINS_OF > +/* > + * DEVICE TREE BASED POWER DOMAIN PROVIDERS > + * > + * The code below implements generic device tree based power domain providers > + * that bind device tree nodes with generic power domains registered in the > + * system. > + * > + * Any driver that registers generic power domains and need to support binding > + * of devices to these domains is supposed to register a power domain provider, > + * which maps a power domain specifier retrieved from device tree to a power > + * domain. > + * > + * Two simple mapping functions have been provided for convenience: > + * - of_genpd_xlate_simple() for 1:1 device tree node to domain mapping, > + * - of_genpd_xlate_onecell() for mapping of multiple domains per node > + * by index. > + */ > + > +/** > + * struct of_genpd_provider - Power domain provider registration structure > + * @link: Entry in global list of domain providers > + * @node: Pointer to device tree node of domain provider > + * @xlate: Provider-specific xlate callback mapping a set of specifier cells > + * into a power domain. > + * @data: context pointer to be passed into @xlate callback > + */ > +struct of_genpd_provider { > + struct list_head link; > + > + struct device_node *node; > + genpd_xlate_t xlate; > + void *data; > +}; > + > +/* List of registered power domain providers. */ > +static LIST_HEAD(of_genpd_providers); > +/* Mutex to protect the list above. */ > +static DEFINE_MUTEX(of_genpd_mutex); > + > +/** > + * of_genpd_lock() - Lock access to of_genpd_providers list > + */ > +static void of_genpd_lock(void) > +{ > + mutex_lock(&of_genpd_mutex); > +} > + > +/** > + * of_genpd_unlock() - Unlock access to of_genpd_providers list > + */ > +static void of_genpd_unlock(void) > +{ > + mutex_unlock(&of_genpd_mutex); > +} > + > +/** > + * of_genpd_xlate_simple() - Xlate function for direct node-domain mapping > + * @genpdspec: OF phandle args to map into a power domain > + * @data: xlate function private data - pointer to struct generic_pm_domain > + * > + * This is a generic xlate function that can be used to model power domains > + * that have their own device tree nodes. The private data of xlate function > + * needs to be a valid pointer to struct generic_pm_domain. > + */ > +struct generic_pm_domain *of_genpd_xlate_simple( > + struct of_phandle_args *genpdspec, > + void *data) > +{ > + if (genpdspec->args_count != 0) > + return ERR_PTR(-EINVAL); > + return data; > +} > +EXPORT_SYMBOL_GPL(of_genpd_xlate_simple); > + > +/** > + * of_genpd_xlate_onecell() - Xlate function for providers using single index. > + * @genpdspec: OF phandle args to map into a power domain > + * @data: xlate function private data - pointer to struct genpd_onecell_data > + * > + * This is a generic xlate function that can be used to model simple power > + * domain controllers that have one device tree node and provide multiple > + * power domains. A single cell is used as an index to an array of power > + * domains specified in genpd_onecell_data struct when registering the > + * provider. > + */ > +struct generic_pm_domain *of_genpd_xlate_onecell( > + struct of_phandle_args *genpdspec, > + void *data) > +{ > + struct genpd_onecell_data *genpd_data = data; > + unsigned int idx = genpdspec->args[0]; > + > + if (genpdspec->args_count != 1) > + return ERR_PTR(-EINVAL); > + > + if (idx >= genpd_data->domain_num) { > + pr_err("%s: invalid domain index %d\n", __func__, idx); > + return ERR_PTR(-EINVAL); > + } > + > + return genpd_data->domains[idx]; > +} > +EXPORT_SYMBOL_GPL(of_genpd_xlate_onecell); > + > +/** > + * of_genpd_add_provider() - Register a domain provider for a node > + * @np: Device node pointer associated with domain provider > + * @genpd_src_get: callback for decoding domain > + * @data: context pointer for @genpd_src_get callback. > + */ > +int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate, > + void *data) > +{ > + struct of_genpd_provider *cp; > + > + cp = kzalloc(sizeof(struct of_genpd_provider), GFP_KERNEL); > + if (!cp) > + return -ENOMEM; > + > + cp->node = of_node_get(np); > + cp->data = data; > + cp->xlate = xlate; > + > + of_genpd_lock(); > + list_add(&cp->link, &of_genpd_providers); > + of_genpd_unlock(); > + pr_debug("Added domain provider from %s\n", np->full_name); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(of_genpd_add_provider); > + > +/** > + * of_genpd_del_provider() - Remove a previously registered domain provider > + * @np: Device node pointer associated with domain provider > + */ > +void of_genpd_del_provider(struct device_node *np) > +{ > + struct of_genpd_provider *cp; > + > + of_genpd_lock(); > + list_for_each_entry(cp, &of_genpd_providers, link) { > + if (cp->node == np) { > + list_del(&cp->link); > + of_node_put(cp->node); > + kfree(cp); > + break; > + } > + } > + of_genpd_unlock(); > +} > +EXPORT_SYMBOL_GPL(of_genpd_del_provider); > + > +/* See of_genpd_get_from_provider(). */ > +static struct generic_pm_domain *__of_genpd_get_from_provider( > + struct of_phandle_args *genpdspec) > +{ > + struct of_genpd_provider *provider; > + struct generic_pm_domain *genpd = ERR_PTR(-ENOENT); > + > + /* Check if we have such a provider in our array */ > + list_for_each_entry(provider, &of_genpd_providers, link) { > + if (provider->node == genpdspec->np) > + genpd = provider->xlate(genpdspec, provider->data); > + if (!IS_ERR(genpd)) > + break; > + } > + > + return genpd; > +} > + > +/** > + * of_genpd_get_from_provider() - Look-up power domain > + * @genpdspec: OF phandle args to use for look-up > + * > + * Looks for domain provider under node specified by @genpdspec and if found > + * uses xlate function of the provider to map phandle args to a power domain. > + * > + * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR() > + * on failure. > + */ > +static struct generic_pm_domain *of_genpd_get_from_provider( > + struct of_phandle_args *genpdspec) > +{ > + struct generic_pm_domain *genpd; > + > + of_genpd_lock(); > + genpd = __of_genpd_get_from_provider(genpdspec); > + of_genpd_unlock(); > + > + return genpd; > +} > + > +/* > + * DEVICE<->DOMAIN BINDING USING DEVICE TREE LOOK-UP > + * > + * The code below registers a notifier for platform bus devices' > + * BUS_NOTIFY_BIND_DRIVER events and tries to attach devices to their power > + * domains by looking them up using Device Tree. > + * > + * Similarly in BUS_NOTIFY_UNBOUND_DRIVER the device is detached from its > + * domain, since it no longer supports runtime PM without any driver bound > + * to it. > + * > + * Both generic and legacy Samsung-specific DT bindings are supported to > + * keep backwards compatibility with existing DTBs. > + */ > + > +/** > + * of_genpd_add_to_domain - Bind device to its power domain using Device Tree. > + * @dev: Device to bind to its power domain. > + * > + * Tries to parse power domain specifier from device's OF node and if succeeds > + * attaches the device to retrieved power domain. > + * > + * Returns 0 on success or negative error code otherwise. > + */ > +static int of_genpd_add_to_domain(struct device *dev) > +{ > + struct of_phandle_args pd_args; > + struct generic_pm_domain *pd; > + int ret; > + > + ret = of_parse_phandle_with_args(dev->of_node, "power-domain", > + "#power-domain-cells", 0, &pd_args); > + if (ret < 0) { > + if (ret != ENOENT) > + return ret; > + > + /* > + * Try legacy Samsung-specific bindings > + * (for backwards compatibility of DT ABI) > + */ > + pd_args.args_count = 0; > + pd_args.np = of_parse_phandle(dev->of_node, > + "samsung,power-domain", 0); > + if (!pd_args.np) > + return 0; > + } > + > + pd = of_genpd_get_from_provider(&pd_args); > + if (IS_ERR(pd)) > + return PTR_ERR(pd); > + > + dev_dbg(dev, "adding to power domain %s\n", pd->name); > + > + while (1) { > + ret = pm_genpd_add_device(pd, dev); > + if (ret != -EAGAIN) > + break; > + cond_resched(); > + } > + > + if (!ret) > + pm_genpd_dev_need_restore(dev, true); > + > + return ret; > +} > + > +/** > + * of_genpd_del_from_domain - Unbind device from its power domain. > + * @dev: Device to unbind from its power domain. > + * > + * Unbinds device from power domain previously bound to it. > + * > + * Returns 0 on success or negative error code otherwise. > + */ > +static int of_genpd_del_from_domain(struct device *dev) > +{ > + struct generic_pm_domain *genpd = dev_to_genpd(dev); > + int ret; > + > + if (IS_ERR(genpd)) > + return 0; > + > + dev_dbg(dev, "removing from power domain %s\n", genpd->name); > + > + while (1) { > + ret = pm_genpd_remove_device(genpd, dev); > + if (ret != -EAGAIN) > + break; > + cond_resched(); > + } > + > + return ret; > +} > + > +/** > + * of_genpd_notifier_call - Receive device driver bind/unbind events > + * @nb: Notifier block which sent the event. > + * @event: Received event. > + * @data: Data attached to received event (struct device *). > + * > + * Registered handler for device driver bind/unbind events that lets the > + * code above perform the magic of adding/removing devices to/from its > + * power domains. > + */ > +static int of_genpd_notifier_call(struct notifier_block *nb, > + unsigned long event, void *data) > +{ > + struct device *dev = data; > + int ret; > + > + if (!dev->of_node) > + return NOTIFY_DONE; > + > + switch (event) { > + case BUS_NOTIFY_BIND_DRIVER: > + ret = of_genpd_add_to_domain(dev); > + break; > + > + case BUS_NOTIFY_UNBOUND_DRIVER: > + ret = of_genpd_del_from_domain(dev); > + break; > + > + default: > + return NOTIFY_DONE; > + } > + > + return notifier_from_errno(ret); > +} > + > +static struct notifier_block of_genpd_notifier_block = { > + .notifier_call = of_genpd_notifier_call, > +}; > + > +static int of_genpd_init(void) > +{ > + return bus_register_notifier(&platform_bus_type, > + &of_genpd_notifier_block); > +} > +core_initcall(of_genpd_init); > +#endif > diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h > index 7c1d252..08adac0 100644 > --- a/include/linux/pm_domain.h > +++ b/include/linux/pm_domain.h > @@ -310,4 +310,38 @@ static inline void pm_genpd_syscore_poweron(struct device *dev) > pm_genpd_syscore_switch(dev, false); > } > > +/* OF power domain providers */ > +struct of_device_id; > + > +struct genpd_onecell_data { > + struct generic_pm_domain **domains; > + unsigned int domain_num; > +}; > + > +typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args, > + void *data); > + > +#ifdef CONFIG_PM_GENERIC_DOMAINS_OF > +int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate, > + void *data); > +void of_genpd_del_provider(struct device_node *np); > + > +struct generic_pm_domain *of_genpd_xlate_simple( > + struct of_phandle_args *genpdspec, > + void *data); > +struct generic_pm_domain *of_genpd_xlate_onecell( > + struct of_phandle_args *genpdspec, > + void *data); > +#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */ > +static inline int of_genpd_add_provider(struct device_node *np, > + genpd_xlate_t xlate, void *data) > +{ > + return 0; > +} > +static inline void of_genpd_del_provider(struct device_node *np) {} > + > +#define of_genpd_xlate_simple NULL > +#define of_genpd_xlate_onecell NULL > +#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */ > + > #endif /* _LINUX_PM_DOMAIN_H */ > diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig > index 2fac9cc..45aa98e 100644 > --- a/kernel/power/Kconfig > +++ b/kernel/power/Kconfig > @@ -306,6 +306,10 @@ config PM_GENERIC_DOMAINS_RUNTIME > def_bool y > depends on PM_RUNTIME && PM_GENERIC_DOMAINS > > +config PM_GENERIC_DOMAINS_OF > + def_bool y > + depends on PM_GENERIC_DOMAINS && OF && !ARCH_EXYNOS > + > config CPU_PM > bool > depends on SUSPEND || CPU_IDLE > -- > 1.8.5.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
