| Message ID | 20180531105959.14843-5-ulf.hansson@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
Hi Ulf, Am Donnerstag, den 31.05.2018, 12:59 +0200 schrieb Ulf Hansson: > To support devices being partitioned across multiple PM domains, let's > begin with extending genpd to cope with these kind of configurations. > > Therefore, add a new exported function genpd_dev_pm_attach_by_id(), which > is similar to the existing genpd_dev_pm_attach(), but with the difference > that it allows its callers to provide an index to the PM domain that it > wants to attach. > > Note that, genpd_dev_pm_attach_by_id() shall only be called by the driver > core / PM core, similar to how the existing dev_pm_domain_attach() makes > use of genpd_dev_pm_attach(). However, this is implemented by following > changes on top. by_id() APIs are not really intuitive to use for driver writers. Other subsystems have solved this by providing a "-names" property to give the phandles a bit more meaning and then providing a by_name API. I would really appreciate if PM domains could move in the same direction. Regards, Lucas > Because, only one PM domain can be attached per device, genpd needs to > create a virtual device that it can attach/detach instead. More precisely, > let the new function genpd_dev_pm_attach_by_id() register a virtual struct > device via calling device_register(). Then let it attach this device to the > corresponding PM domain, rather than the one that is provided by the > caller. The actual attaching is done via re-using the existing genpd OF > functions. > > At successful attachment, genpd_dev_pm_attach_by_id() returns the created > virtual device, which allows the caller to operate on it to deal with power > management. Following changes on top, provides more details in this > regards. > > To deal with detaching of a PM domain for the multiple PM domains case, > let's also extend the existing genpd_dev_pm_detach() function, to cover the > cleanup of the created virtual device, via make it call device_unregister() > on it. In this way, there is no need to introduce a new function to deal > with detach for the multiple PM domain case, but instead the existing one > is re-used. > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > Acked-by: Jon Hunter <jonathanh@nvidia.com> > Tested-by: Jon Hunter <jonathanh@nvidia.com> > Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/base/power/domain.c | 80 +++++++++++++++++++++++++++++++++++++ > include/linux/pm_domain.h | 8 ++++ > 2 files changed, 88 insertions(+) > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > index b1fcbf917974..4925af5c4cf0 100644 > --- a/drivers/base/power/domain.c > +++ b/drivers/base/power/domain.c > @@ -2171,6 +2171,15 @@ struct generic_pm_domain *of_genpd_remove_last(struct device_node *np) > } > EXPORT_SYMBOL_GPL(of_genpd_remove_last); > > +static void genpd_release_dev(struct device *dev) > +{ > + kfree(dev); > +} > + > +static struct bus_type genpd_bus_type = { > + .name = "genpd", > +}; > + > /** > * genpd_dev_pm_detach - Detach a device from its PM domain. > * @dev: Device to detach. > @@ -2208,6 +2217,10 @@ static void genpd_dev_pm_detach(struct device *dev, bool power_off) > > /* Check if PM domain can be powered off after removing this device. */ > genpd_queue_power_off_work(pd); > + > + /* Unregister the device if it was created by genpd. */ > + if (dev->bus == &genpd_bus_type) > + device_unregister(dev); > } > > static void genpd_dev_pm_sync(struct device *dev) > @@ -2298,6 +2311,67 @@ int genpd_dev_pm_attach(struct device *dev) > } > EXPORT_SYMBOL_GPL(genpd_dev_pm_attach); > > +/** > + * genpd_dev_pm_attach_by_id - Associate a device with one of its PM domains. > + * @dev: The device used to lookup the PM domain. > + * @index: The index of the PM domain. > + * > + * Parse device's OF node to find a PM domain specifier at the provided @index. > + * If such is found, creates a virtual device and attaches it to the retrieved > + * pm_domain ops. To deal with detaching of the virtual device, the ->detach() > + * callback in the struct dev_pm_domain are assigned to genpd_dev_pm_detach(). > + * > + * Returns the created virtual device if successfully attached PM domain, NULL > + * when the device don't need a PM domain, else an ERR_PTR() in case of > + * failures. If a power-domain exists for the device, but cannot be found or > + * turned on, then ERR_PTR(-EPROBE_DEFER) is returned to ensure that the device > + * is not probed and to re-try again later. > + */ > +struct device *genpd_dev_pm_attach_by_id(struct device *dev, > + unsigned int index) > +{ > + struct device *genpd_dev; > + int num_domains; > + int ret; > + > + if (!dev->of_node) > + return NULL; > + > + /* Deal only with devices using multiple PM domains. */ > + num_domains = of_count_phandle_with_args(dev->of_node, "power-domains", > + "#power-domain-cells"); > + if (num_domains < 2 || index >= num_domains) > + return NULL; > + > + /* Allocate and register device on the genpd bus. */ > + genpd_dev = kzalloc(sizeof(*genpd_dev), GFP_KERNEL); > + if (!genpd_dev) > + return ERR_PTR(-ENOMEM); > + > + dev_set_name(genpd_dev, "genpd:%u:%s", index, dev_name(dev)); > + genpd_dev->bus = &genpd_bus_type; > + genpd_dev->release = genpd_release_dev; > + > + ret = device_register(genpd_dev); > + if (ret) { > + kfree(genpd_dev); > + return ERR_PTR(ret); > + } > + > + /* Try to attach the device to the PM domain at the specified index. */ > + ret = __genpd_dev_pm_attach(genpd_dev, dev->of_node, index); > + if (ret < 1) { > + device_unregister(genpd_dev); > + return ret ? ERR_PTR(ret) : NULL; > + } > + > + pm_runtime_set_active(genpd_dev); > + pm_runtime_enable(genpd_dev); > + > + return genpd_dev; > +} > +EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_by_id); > + > static const struct of_device_id idle_state_match[] = { > { .compatible = "domain-idle-state", }, > { } > @@ -2457,6 +2531,12 @@ unsigned int of_genpd_opp_to_performance_state(struct device *dev, > } > EXPORT_SYMBOL_GPL(of_genpd_opp_to_performance_state); > > +static int __init genpd_bus_init(void) > +{ > + return bus_register(&genpd_bus_type); > +} > +core_initcall(genpd_bus_init); > + > #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */ > > > diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h > index 42e0d649e653..82458e8e2e01 100644 > --- a/include/linux/pm_domain.h > +++ b/include/linux/pm_domain.h > @@ -237,6 +237,8 @@ unsigned int of_genpd_opp_to_performance_state(struct device *dev, > struct device_node *opp_node); > > int genpd_dev_pm_attach(struct device *dev); > +struct device *genpd_dev_pm_attach_by_id(struct device *dev, > + unsigned int index); > #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */ > static inline int of_genpd_add_provider_simple(struct device_node *np, > struct generic_pm_domain *genpd) > @@ -282,6 +284,12 @@ static inline int genpd_dev_pm_attach(struct device *dev) > return 0; > } > > +static inline struct device *genpd_dev_pm_attach_by_id(struct device *dev, > + unsigned int index) > +{ > + return NULL; > +} > + > static inline > struct generic_pm_domain *of_genpd_remove_last(struct device_node *np) > {
On 31/05/18 12:40, Lucas Stach wrote: > Hi Ulf, > > Am Donnerstag, den 31.05.2018, 12:59 +0200 schrieb Ulf Hansson: >> To support devices being partitioned across multiple PM domains, let's >> begin with extending genpd to cope with these kind of configurations. >> >> Therefore, add a new exported function genpd_dev_pm_attach_by_id(), which >> is similar to the existing genpd_dev_pm_attach(), but with the difference >> that it allows its callers to provide an index to the PM domain that it >> wants to attach. >> >> Note that, genpd_dev_pm_attach_by_id() shall only be called by the driver >> core / PM core, similar to how the existing dev_pm_domain_attach() makes >> use of genpd_dev_pm_attach(). However, this is implemented by following >> changes on top. > > by_id() APIs are not really intuitive to use for driver writers. Other > subsystems have solved this by providing a "-names" property to give > the phandles a bit more meaning and then providing a by_name API. I > would really appreciate if PM domains could move in the same direction. As discussed here [0], there are plans to add that. Cheers Jon [0] https://patchwork.ozlabs.org/patch/921938/
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index b1fcbf917974..4925af5c4cf0 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -2171,6 +2171,15 @@ struct generic_pm_domain *of_genpd_remove_last(struct device_node *np) } EXPORT_SYMBOL_GPL(of_genpd_remove_last); +static void genpd_release_dev(struct device *dev) +{ + kfree(dev); +} + +static struct bus_type genpd_bus_type = { + .name = "genpd", +}; + /** * genpd_dev_pm_detach - Detach a device from its PM domain. * @dev: Device to detach. @@ -2208,6 +2217,10 @@ static void genpd_dev_pm_detach(struct device *dev, bool power_off) /* Check if PM domain can be powered off after removing this device. */ genpd_queue_power_off_work(pd); + + /* Unregister the device if it was created by genpd. */ + if (dev->bus == &genpd_bus_type) + device_unregister(dev); } static void genpd_dev_pm_sync(struct device *dev) @@ -2298,6 +2311,67 @@ int genpd_dev_pm_attach(struct device *dev) } EXPORT_SYMBOL_GPL(genpd_dev_pm_attach); +/** + * genpd_dev_pm_attach_by_id - Associate a device with one of its PM domains. + * @dev: The device used to lookup the PM domain. + * @index: The index of the PM domain. + * + * Parse device's OF node to find a PM domain specifier at the provided @index. + * If such is found, creates a virtual device and attaches it to the retrieved + * pm_domain ops. To deal with detaching of the virtual device, the ->detach() + * callback in the struct dev_pm_domain are assigned to genpd_dev_pm_detach(). + * + * Returns the created virtual device if successfully attached PM domain, NULL + * when the device don't need a PM domain, else an ERR_PTR() in case of + * failures. If a power-domain exists for the device, but cannot be found or + * turned on, then ERR_PTR(-EPROBE_DEFER) is returned to ensure that the device + * is not probed and to re-try again later. + */ +struct device *genpd_dev_pm_attach_by_id(struct device *dev, + unsigned int index) +{ + struct device *genpd_dev; + int num_domains; + int ret; + + if (!dev->of_node) + return NULL; + + /* Deal only with devices using multiple PM domains. */ + num_domains = of_count_phandle_with_args(dev->of_node, "power-domains", + "#power-domain-cells"); + if (num_domains < 2 || index >= num_domains) + return NULL; + + /* Allocate and register device on the genpd bus. */ + genpd_dev = kzalloc(sizeof(*genpd_dev), GFP_KERNEL); + if (!genpd_dev) + return ERR_PTR(-ENOMEM); + + dev_set_name(genpd_dev, "genpd:%u:%s", index, dev_name(dev)); + genpd_dev->bus = &genpd_bus_type; + genpd_dev->release = genpd_release_dev; + + ret = device_register(genpd_dev); + if (ret) { + kfree(genpd_dev); + return ERR_PTR(ret); + } + + /* Try to attach the device to the PM domain at the specified index. */ + ret = __genpd_dev_pm_attach(genpd_dev, dev->of_node, index); + if (ret < 1) { + device_unregister(genpd_dev); + return ret ? ERR_PTR(ret) : NULL; + } + + pm_runtime_set_active(genpd_dev); + pm_runtime_enable(genpd_dev); + + return genpd_dev; +} +EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_by_id); + static const struct of_device_id idle_state_match[] = { { .compatible = "domain-idle-state", }, { } @@ -2457,6 +2531,12 @@ unsigned int of_genpd_opp_to_performance_state(struct device *dev, } EXPORT_SYMBOL_GPL(of_genpd_opp_to_performance_state); +static int __init genpd_bus_init(void) +{ + return bus_register(&genpd_bus_type); +} +core_initcall(genpd_bus_init); + #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */ diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 42e0d649e653..82458e8e2e01 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -237,6 +237,8 @@ unsigned int of_genpd_opp_to_performance_state(struct device *dev, struct device_node *opp_node); int genpd_dev_pm_attach(struct device *dev); +struct device *genpd_dev_pm_attach_by_id(struct device *dev, + unsigned int index); #else /* !CONFIG_PM_GENERIC_DOMAINS_OF */ static inline int of_genpd_add_provider_simple(struct device_node *np, struct generic_pm_domain *genpd) @@ -282,6 +284,12 @@ static inline int genpd_dev_pm_attach(struct device *dev) return 0; } +static inline struct device *genpd_dev_pm_attach_by_id(struct device *dev, + unsigned int index) +{ + return NULL; +} + static inline struct generic_pm_domain *of_genpd_remove_last(struct device_node *np) {