On 8 September 2014 00:13, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > On Thursday, September 04, 2014 03:52:29 PM Ulf Hansson wrote: >> From: Tomasz Figa <t.figa@xxxxxxxxxxx> >> >> This patch introduces generic code to perform PM domain look-up using >> device tree and automatically bind devices to their PM domains. >> >> Generic device tree bindings are introduced to specify PM domains of >> devices in their device tree nodes. >> >> Backwards compatibility with legacy Samsung-specific PM 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 the Exynos PM domain code gets converted to >> use the generic framework in further patch. >> >> Signed-off-by: Tomasz Figa <t.figa@xxxxxxxxxxx> >> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> >> [Ulf:Added attach|detach functions, fixed review comments] >> Tested-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > However, for this one (and consequently the rest) I need an ACK from the > people who maintain the bindings. These DT bindings have been discussed between Tomasz and devicetree maintainers previously. So I think there are fine. Also, when browsing the mail-archives, I found an ack from Rob Herrring: http://lists.infradead.org/pipermail/linux-arm-kernel/2014-March/237989.html I realize that I didn't put the DT maintainers on the to-line when posting this patch, but just the devicetree list. I have now included them on this reply, but maybe I should repost instead. What do you think? Are you happy with the above ack from Rob? Kind regards Uffe > >> --- >> .../devicetree/bindings/power/power_domain.txt | 49 ++++ >> drivers/base/power/domain.c | 291 +++++++++++++++++++++ >> include/linux/pm_domain.h | 57 ++++ >> kernel/power/Kconfig | 4 + >> 4 files changed, 401 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..98c1667 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/power/power_domain.txt >> @@ -0,0 +1,49 @@ >> +* Generic PM domains >> + >> +System on chip designs are often divided into multiple PM 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 PM domain consumer devices with >> +their PM domains provided by PM domain providers. A PM domain provider can be >> +represented by any node in the device tree and can provide one or more PM >> +domains. A consumer node can refer to the provider by a phandle and a set of >> +phandle arguments (so called PM domain specifiers) of length specified by the >> +#power-domain-cells property in the PM domain provider node. >> + >> +==PM domain providers== >> + >> +Required properties: >> + - #power-domain-cells : Number of cells in a PM domain specifier; >> + Typically 0 for nodes representing a single PM domain and 1 for nodes >> + providing multiple PM 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 PM domain provider and >> +expects one cell as its phandle argument. >> + >> +==PM domain consumers== >> + >> +Required properties: >> + - power-domains : A phandle and PM domain specifier as defined by bindings of >> + the 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 PM domain consumer device, which is located >> +inside a PM domain with index 0 of a power controller represented by a node >> +with the label "power". >> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >> index eee55c1..ed42651 100644 >> --- a/drivers/base/power/domain.c >> +++ b/drivers/base/power/domain.c >> @@ -8,6 +8,7 @@ >> >> #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> >> @@ -2189,3 +2190,293 @@ 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 PM domain providers. >> + * >> + * The code below implements generic device tree based PM domain providers that >> + * bind device tree nodes with generic PM domains registered in the system. >> + * >> + * Any driver that registers generic PM domains and needs to support binding of >> + * devices to these domains is supposed to register a PM domain provider, which >> + * maps a PM domain specifier retrieved from the device tree to a PM domain. >> + * >> + * Two simple mapping functions have been provided for convenience: >> + * - __of_genpd_xlate_simple() for 1:1 device tree node to PM domain mapping. >> + * - __of_genpd_xlate_onecell() for mapping of multiple PM domains per node by >> + * index. >> + */ >> + >> +/** >> + * struct of_genpd_provider - PM domain provider registration structure >> + * @link: Entry in global list of PM domain providers >> + * @node: Pointer to device tree node of PM domain provider >> + * @xlate: Provider-specific xlate callback mapping a set of specifier cells >> + * into a PM 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 PM 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 PM domain >> + * @data: xlate function private data - pointer to struct generic_pm_domain >> + * >> + * This is a generic xlate function that can be used to model PM 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 using a single index. >> + * @genpdspec: OF phandle args to map into a PM 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 PM domain >> + * controllers that have one device tree node and provide multiple PM domains. >> + * A single cell is used as an index into an array of PM domains specified in >> + * the 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->num_domains) { >> + pr_err("%s: invalid domain index %u\n", __func__, idx); >> + return ERR_PTR(-EINVAL); >> + } >> + >> + if (!genpd_data->domains[idx]) >> + return ERR_PTR(-ENOENT); >> + >> + return genpd_data->domains[idx]; >> +} >> +EXPORT_SYMBOL_GPL(__of_genpd_xlate_onecell); >> + >> +/** >> + * __of_genpd_add_provider() - Register a PM domain provider for a node >> + * @np: Device node pointer associated with the PM domain provider. >> + * @xlate: Callback for decoding PM domain from phandle arguments. >> + * @data: Context pointer for @xlate 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 PM domain provider >> + * @np: Device node pointer associated with the PM 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 PM domain >> + * @genpdspec: OF phandle args to use for look-up >> + * >> + * Looks for a PM domain provider under the node specified by @genpdspec and if >> + * found, uses xlate function of the provider to map phandle args to a PM >> + * 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(-ENOENT); >> + 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; >> +} >> + >> +/** >> + * genpd_dev_pm_attach - Attach a device to its PM domain using DT. >> + * @dev: Device to attach. >> + * >> + * Parse device's OF node to find a PM domain specifier. If such is found, >> + * attaches the device to retrieved pm_domain ops. >> + * >> + * Both generic and legacy Samsung-specific DT bindings are supported to keep >> + * backwards compatibility with existing DTBs. >> + * >> + * Returns 0 on successfully attached PM domain or negative error code. >> + */ >> +int genpd_dev_pm_attach(struct device *dev) >> +{ >> + struct of_phandle_args pd_args; >> + struct generic_pm_domain *pd; >> + int ret; >> + >> + if (!dev->of_node) >> + return -ENODEV; >> + >> + if (dev->pm_domain) >> + return -EEXIST; >> + >> + 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 -ENOENT; >> + } >> + >> + pd = of_genpd_get_from_provider(&pd_args); >> + if (IS_ERR(pd)) { >> + dev_dbg(dev, "%s() failed to find PM domain: %ld\n", >> + __func__, PTR_ERR(pd)); >> + of_node_put(dev->of_node); >> + return PTR_ERR(pd); >> + } >> + >> + dev_dbg(dev, "adding to PM 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 PM domain %s: %d", >> + pd->name, ret); >> + of_node_put(dev->of_node); >> + return ret; >> + } >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(genpd_dev_pm_attach); >> + >> +/** >> + * genpd_dev_pm_detach - Detach a device from its PM domain. >> + * @dev: Device to attach. >> + * >> + * Try to locate a corresponding generic PM domain, which the device was >> + * attached to previously. If such is found, the device is detached from it. >> + * >> + * Returns 0 on successfully detached PM domain or negative error code. >> + */ >> +int genpd_dev_pm_detach(struct device *dev) >> +{ >> + struct generic_pm_domain *pd = NULL, *gpd; >> + int ret = 0; >> + >> + if (!dev->pm_domain) >> + return -ENODEV; >> + >> + mutex_lock(&gpd_list_lock); >> + list_for_each_entry(gpd, &gpd_list, gpd_list_node) { >> + if (&gpd->domain == dev->pm_domain) { >> + pd = gpd; >> + break; >> + } >> + } >> + mutex_unlock(&gpd_list_lock); >> + >> + if (!pd) >> + return -ENOENT; >> + >> + dev_dbg(dev, "removing from PM 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 PM domain %s: %d", >> + pd->name, ret); >> + return ret; >> + } >> + >> + /* Check if PM domain can be powered off after removing this device. */ >> + genpd_queue_power_off_work(pd); >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(genpd_dev_pm_detach); >> +#endif >> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h >> index ebc4c76..b09eaa7 100644 >> --- a/include/linux/pm_domain.h >> +++ b/include/linux/pm_domain.h >> @@ -310,4 +310,61 @@ static inline void pm_genpd_syscore_poweron(struct device *dev) >> pm_genpd_syscore_switch(dev, false); >> } >> >> +/* OF PM domain providers */ >> +struct of_device_id; >> + >> +struct genpd_onecell_data { >> + struct generic_pm_domain **domains; >> + unsigned int num_domains; >> +}; >> + >> +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_dev_pm_attach(struct device *dev); >> +int genpd_dev_pm_detach(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_dev_pm_attach(struct device *dev) >> +{ >> + return -ENODEV; >> +} >> +static inline int genpd_dev_pm_detach(struct device *dev) >> +{ >> + return -ENODEV; >> +} >> +#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */ >> + >> +static inline int of_genpd_add_provider_simple(struct device_node *np, >> + struct generic_pm_domain *genpd) >> +{ >> + return __of_genpd_add_provider(np, __of_genpd_xlate_simple, genpd); >> +} >> +static inline int of_genpd_add_provider_onecell(struct device_node *np, >> + struct genpd_onecell_data *data) >> +{ >> + return __of_genpd_add_provider(np, __of_genpd_xlate_onecell, data); >> +} >> + >> #endif /* _LINUX_PM_DOMAIN_H */ >> diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig >> index e4e4121..897619b 100644 >> --- a/kernel/power/Kconfig >> +++ b/kernel/power/Kconfig >> @@ -302,6 +302,10 @@ 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 >> > > -- > I speak only for myself. > Rafael J. Wysocki, Intel Open Source Technology Center. -- 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
