diff options
| -rw-r--r-- | Documentation/devicetree/bindings/power/power_domain.txt | 51 | ||||
| -rw-r--r-- | drivers/base/power/domain.c | 283 | ||||
| -rw-r--r-- | include/linux/pm_domain.h | 46 | ||||
| -rw-r--r-- | kernel/power/Kconfig | 4 |
4 files changed, 384 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt new file mode 100644 index 000000000000..303d0a968569 --- /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-domains : 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-domains = <&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 bfb8955c406c..5ab3d9e1409e 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -9,6 +9,7 @@ #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 +2178,285 @@ 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_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. + * @xlate: Callback for decoding domain from phandle arguments. + * @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(*cp), GFP_KERNEL); + if (!cp) + return -ENOMEM; + + cp->node = of_node_get(np); + cp->data = data; + cp->xlate = xlate; + + mutex_lock(&of_genpd_mutex); + list_add(&cp->link, &of_genpd_providers); + mutex_unlock(&of_genpd_mutex); + 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; + + mutex_lock(&of_genpd_mutex); + 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; + } + } + mutex_unlock(&of_genpd_mutex); +} +EXPORT_SYMBOL_GPL(of_genpd_del_provider); + +/** + * 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 = ERR_PTR(-EPROBE_DEFER); + struct of_genpd_provider *provider; + + mutex_lock(&of_genpd_mutex); + + /* 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; + } + + mutex_unlock(&of_genpd_mutex); + + return genpd; +} + +/* + * Device<->domain binding using Device Tree look-up. + * + * The purpose of code below is to manage assignment of devices to their + * power domains in an automatic fashion, based on data read from device tree. + * The two functions, genpd_bind_domain() and genpd_unbind_domain() are + * intended to be called by higher level code that manages devices, i.e. + * really_probe() and __device_release_driver() to respectively bind and + * unbind device from its power domain. + * + * Both generic and legacy Samsung-specific DT bindings are supported to + * keep backwards compatibility with existing DTBs. + */ + +/** + * genpd_bind_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. + */ +int genpd_bind_domain(struct device *dev) +{ + struct of_phandle_args pd_args; + struct generic_pm_domain *pd; + int ret; + + if (!dev->of_node) + return 0; + + ret = of_parse_phandle_with_args(dev->of_node, "power-domains", + "#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)) { + if (PTR_ERR(pd) != -EPROBE_DEFER) + dev_err(dev, "failed to find power domain: %ld\n", + PTR_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 < 0) { + dev_err(dev, "failed to add to power domain %s: %d", + pd->name, ret); + return ret; + } + + return 0; +} + +/** + * genpd_unbind_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. + */ +int genpd_unbind_domain(struct device *dev) +{ + struct generic_pm_domain *pd = dev_to_genpd(dev); + int ret; + + if (!dev->of_node || IS_ERR(pd)) + return 0; + + dev_dbg(dev, "removing from power domain %s\n", pd->name); + + while (1) { + ret = pm_genpd_remove_device(pd, dev); + if (ret != -EAGAIN) + break; + cond_resched(); + } + + if (ret < 0) { + dev_err(dev, "failed to remove from power domain %s: %d", + pd->name, ret); + return ret; + } + + /* Check if domain can be powered off after removing this device. */ + genpd_queue_power_off_work(pd); + + return 0; +} +#endif diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 7c1d252b20c0..04473d4e0aa3 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -310,4 +310,50 @@ 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); + +int genpd_bind_domain(struct device *dev); +int genpd_unbind_domain(struct device *dev); +#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 + +static inline int genpd_bind_domain(struct device *dev) +{ + return 0; +} +static inline int genpd_unbind_domain(struct device *dev) +{ + return 0; +} +#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */ + #endif /* _LINUX_PM_DOMAIN_H */ diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index 2fac9cc79b3d..45aa98ee5a70 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 |