lkml.org 
[lkml]   [2014]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    SubjectRe: [PATCH v2 01/11] base: power: Add generic OF-based power domain look-up
    From
    On 3 March 2014 17:02, Tomasz Figa <tomasz.figa@gmail.com> 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@gmail.com>
    > ---
    > .../devicetree/bindings/power/power_domain.txt | 51 ++++
    > drivers/base/power/domain.c | 298 +++++++++++++++++++++
    > include/linux/pm_domain.h | 46 ++++
    > kernel/power/Kconfig | 4 +
    > 4 files changed, 399 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.

    I am trying to understand if using a value > 1, ever would make sense.
    Wouldn't that mean each consumer (device) would actually be a part of
    more than one power domain? That won't work, right!?

    Additionally, there are no corresponding parsing method (like
    of_genpd_xlate_onecell() ) that support more than one cell.

    Kind regards
    Ulf Hansson

    > +
    > +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 dc127e5..006b455 100644
    > --- a/drivers/base/power/domain.c
    > +++ b/drivers/base/power/domain.c
    > @@ -3,12 +3,16 @@
    > *
    > * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
    > *
    > + * Support for Device Tree based power domain providers:
    > + * Copyright (C) 2014 Tomasz Figa <tomasz.figa@gmail.com>
    > + *
    > * 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 +2181,297 @@ 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);
    > +
    > +/* 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(-EPROBE_DEFER);
    > +
    > + /* 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;
    > +
    > + mutex_lock(&of_genpd_mutex);
    > + genpd = __of_genpd_get_from_provider(genpdspec);
    > + mutex_unlock(&of_genpd_mutex);
    > +
    > + 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.
    > + */
    > +
    > +/**
    > + * 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-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)) {
    > + 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;
    > + }
    > +
    > + pm_genpd_dev_need_restore(dev, true);
    > +
    > + 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 7c1d252..04473d4 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 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
    > --
    > 1.9.0
    >


    \
     
     \ /
      Last update: 2014-04-05 17:01    [W:2.355 / U:0.364 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site