From: Daniel Baluta daniel.baluta@nxp.com

This patch introduces helpers support for multi PM domains.

API consists of:

1) dev_multi_pm_attach - powers up all PM domains associated with a given device. Because we can attach one PM domain per device, we create virtual devices (children of initial device) and associate PM domains one per virtual device.

2) dev_multi_pm_detach - detaches all virtual devices from PM domains attached with.

Signed-off-by: Daniel Baluta daniel.baluta@nxp.com --- drivers/base/power/common.c | 93 +++++++++++++++++++++++++++++++++++++ include/linux/pm_domain.h | 19 ++++++++ 2 files changed, 112 insertions(+)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c index bbddb267c2e6..b0a4d0109810 100644 --- a/drivers/base/power/common.c +++ b/drivers/base/power/common.c @@ -228,3 +228,96 @@ void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) device_pm_check_callbacks(dev); } EXPORT_SYMBOL_GPL(dev_pm_domain_set); + +/** + * dev_multi_pm_attach - power up device associated power domains + * @dev: The device used to lookup the PM domains + * + * Parse device's OF node to find all PM domains specifiers. For each power + * domain found, create a virtual device and associate it with the + * current power domain. + * + * This function should typically be invoked by a driver during the + * probe phase, in the case its device requires power management through + * multiple PM domains. + * + * Returns a pointer to @dev_multi_pm_domain_data if successfully attached PM + * domains, NULL when the device doesn't need a PM domain or when single + * power-domains exists for it, else an ERR_PTR() in case of + * failures. + */ +struct dev_multi_pm_domain_data *dev_multi_pm_attach(struct device *dev) +{ + struct dev_multi_pm_domain_data *mpd, *retp; + int num_domains; + int i; + + num_domains = of_count_phandle_with_args(dev->of_node, "power-domains", + "#power-domain-cells"); + if (num_domains < 2) + return NULL; + + mpd = devm_kzalloc(dev, sizeof(*mpd), GFP_KERNEL); + if (!mpd) + return ERR_PTR(-ENOMEM); + + mpd->dev = dev; + mpd->num_domains = num_domains; + + mpd->virt_devs = devm_kmalloc_array(dev, mpd->num_domains, + sizeof(*mpd->virt_devs), + GFP_KERNEL); + if (!mpd->virt_devs) + return ERR_PTR(-ENOMEM); + + mpd->links = devm_kmalloc_array(dev, mpd->num_domains, + sizeof(*mpd->links), GFP_KERNEL); + if (!mpd->links) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < mpd->num_domains; i++) { + mpd->virt_devs[i] = dev_pm_domain_attach_by_id(dev, i); + if (IS_ERR(mpd->virt_devs[i])) { + retp = (struct dev_multi_pm_domain_data *) + mpd->virt_devs[i]; + goto exit_unroll_pm; + } + mpd->links[i] = device_link_add(dev, mpd->virt_devs[i], + DL_FLAG_STATELESS | + DL_FLAG_PM_RUNTIME | + DL_FLAG_RPM_ACTIVE); + if (!mpd->links[i]) { + retp = ERR_PTR(-ENOMEM); + dev_pm_domain_detach(mpd->virt_devs[i], false); + goto exit_unroll_pm; + } + } + return mpd; + +exit_unroll_pm: + while (--i >= 0) { + device_link_del(mpd->links[i]); + dev_pm_domain_detach(mpd->virt_devs[i], false); + } + + return retp; +} +EXPORT_SYMBOL(dev_multi_pm_attach); + +/** + * dev_multi_pm_detach - Detach a device from its PM domains. + * Each multi power domain is attached to a virtual children device + * + * @mpd: multi power domains data, contains the association between + * virtul device and PM domain + */ +void dev_multi_pm_detach(struct dev_multi_pm_domain_data *mpd) +{ + int i; + + for (i = 0; i < mpd->num_domains; i++) { + device_link_del(mpd->links[i]); + dev_pm_domain_detach(mpd->virt_devs[i], false); + } +} +EXPORT_SYMBOL(dev_multi_pm_detach); diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 9ec78ee53652..af1107731044 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -183,6 +183,13 @@ struct generic_pm_domain_data { void *data; };

+struct dev_multi_pm_domain_data { + struct device *dev; /* parent device */ + struct device **virt_devs; /* virtual children links */ + struct device_link **links; /* links parent <-> virtual children */ + int num_domains; +}; + #ifdef CONFIG_PM_GENERIC_DOMAINS static inline struct generic_pm_domain_data *to_gpd_data(struct pm_domain_data *pdd) { @@ -369,18 +376,27 @@ struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)

#ifdef CONFIG_PM int dev_pm_domain_attach(struct device *dev, bool power_on); +struct dev_multi_pm_domain_data *dev_multi_pm_attach(struct device *dev); struct device *dev_pm_domain_attach_by_id(struct device *dev, unsigned int index); struct device *dev_pm_domain_attach_by_name(struct device *dev, const char *name); void dev_pm_domain_detach(struct device *dev, bool power_off); int dev_pm_domain_start(struct device *dev); +void dev_multi_pm_detach(struct dev_multi_pm_domain_data *mpd); void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd); + #else static inline int dev_pm_domain_attach(struct device *dev, bool power_on) { return 0; } + +static inline struct dev_multi_pm_domain_data *dev_multi_pm_attach(struct device *dev) +{ + return NULL; +} + static inline struct device *dev_pm_domain_attach_by_id(struct device *dev, unsigned int index) { @@ -396,6 +412,9 @@ static inline int dev_pm_domain_start(struct device *dev) { return 0; } + +static inline void dev_multi_pm_detach(struct dev_multi_pm_domain_data *mpd) {} + static inline void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) {} #endif

On Wed, 24 Jun 2020 at 12:33, Daniel Baluta daniel.baluta@oss.nxp.com wrote:

From: Daniel Baluta daniel.baluta@nxp.com

This patch introduces helpers support for multi PM domains.

API consists of:

1. dev_multi_pm_attach - powers up all PM domains associated with a given

device. Because we can attach one PM domain per device, we create virtual devices (children of initial device) and associate PM domains one per virtual device.

2. dev_multi_pm_detach - detaches all virtual devices from PM domains

attached with.

Nit pick: I suggest to rename the helpers into dev_pm_domain_attach|detach_multi(), to be more consistent with existing function names. It's a bit long I admit that, but I prefer the consistency.

Signed-off-by: Daniel Baluta daniel.baluta@nxp.com

drivers/base/power/common.c | 93 +++++++++++++++++++++++++++++++++++++ include/linux/pm_domain.h | 19 ++++++++ 2 files changed, 112 insertions(+)

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c index bbddb267c2e6..b0a4d0109810 100644 --- a/drivers/base/power/common.c +++ b/drivers/base/power/common.c @@ -228,3 +228,96 @@ void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) device_pm_check_callbacks(dev); } EXPORT_SYMBOL_GPL(dev_pm_domain_set);

+/**

• • dev_multi_pm_attach - power up device associated power domains
• • @dev: The device used to lookup the PM domains
• • Parse device's OF node to find all PM domains specifiers. For each power
• • domain found, create a virtual device and associate it with the
• • current power domain.
• • This function should typically be invoked by a driver during the
• • probe phase, in the case its device requires power management through
• • multiple PM domains.
• • Returns a pointer to @dev_multi_pm_domain_data if successfully attached PM
• • domains, NULL when the device doesn't need a PM domain or when single
• • power-domains exists for it, else an ERR_PTR() in case of
• • failures.
• */

+struct dev_multi_pm_domain_data *dev_multi_pm_attach(struct device *dev) +{

•   struct dev_multi_pm_domain_data *mpd, *retp;
  

•   int num_domains;
  

•   int i;
  

•   num_domains = of_count_phandle_with_args(dev->of_node, "power-domains",
  

•                                            "#power-domain-cells");
  

•   if (num_domains < 2)
  

•           return NULL;
  

dev_pm_domain_attach_* is typically wrapper functions, allowing different types of PM domains to be supported. For example, dev_pm_domain_attach() calls acpi_dev_pm_attach() and genpd_dev_pm_attach(). While dev_pm_domain_attach_by_id() only calls genpd_dev_pm_attach_by_id(), as there's no corresponding interface for the acpi PM domain.

The above said, I don't think another layer should be needed here, but there is something missing that makes this consistent with the behaviour of the above mentioned functions.

How about adding a genpd OF helper ("of_genpd_num_domains(struct device_node *)"), that deals with the above parsing and returns the number of domains for the device? In this way, if of_genpd_num_domains() returns an error code or zero, it's easier to continue to try with other PM domain providers (if/when that is supported).

•   mpd = devm_kzalloc(dev, sizeof(*mpd), GFP_KERNEL);
  

•   if (!mpd)
  

•           return ERR_PTR(-ENOMEM);
  

•   mpd->dev = dev;
  

•   mpd->num_domains = num_domains;
  

•   mpd->virt_devs = devm_kmalloc_array(dev, mpd->num_domains,
  

•                                       sizeof(*mpd->virt_devs),
  

•                                       GFP_KERNEL);
  

•   if (!mpd->virt_devs)
  

•           return ERR_PTR(-ENOMEM);
  

•   mpd->links = devm_kmalloc_array(dev, mpd->num_domains,
  

•                                   sizeof(*mpd->links), GFP_KERNEL);
  

•   if (!mpd->links)
  

•           return ERR_PTR(-ENOMEM);
  

•   for (i = 0; i < mpd->num_domains; i++) {
  

•           mpd->virt_devs[i] = dev_pm_domain_attach_by_id(dev, i);
  

•           if (IS_ERR(mpd->virt_devs[i])) {
  

•                   retp = (struct dev_multi_pm_domain_data *)
  

•                           mpd->virt_devs[i];
  

•                   goto exit_unroll_pm;
  

•           }
  

•           mpd->links[i] = device_link_add(dev, mpd->virt_devs[i],
  

•                                           DL_FLAG_STATELESS |
  

•                                           DL_FLAG_PM_RUNTIME |
  

•                                           DL_FLAG_RPM_ACTIVE);
  

As a suggestion to be a little bit more flexible, perhaps these bits should be given as an in-parameter instead. Potentially we could then also treat the in-parameter being zero, as that no device link should be added.

Although, it's kind of hard to know as the users of this interface aren't really widely known yet.

•           if (!mpd->links[i]) {
  

•                   retp = ERR_PTR(-ENOMEM);
  

•                   dev_pm_domain_detach(mpd->virt_devs[i], false);
  

•                   goto exit_unroll_pm;
  

•           }
  

•   }
  

•   return mpd;
  

+exit_unroll_pm:

•   while (--i >= 0) {
  

•           device_link_del(mpd->links[i]);
  

•           dev_pm_domain_detach(mpd->virt_devs[i], false);
  

•   }
  

•   return retp;
  

+} +EXPORT_SYMBOL(dev_multi_pm_attach);

[...]

Kind regards Uffe