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PM: domains: Add helper functions to attach/detach multiple PM domains

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Attaching/detaching of a device to multiple PM domains has started to
become a common operation for many drivers, typically during ->probe() and
->remove(). In most cases, this has lead to lots of boilerplate code in the
drivers.

To fixup up the situation, let's introduce a pair of helper functions,
dev_pm_domain_attach|detach_list(), that driver can use instead of the
open-coding. Note that, it seems reasonable to limit the support for these
helpers to DT based platforms, at it's the only valid use case for now.

Suggested-by: Daniel Baluta <daniel.baluta@nxp.com>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20240130123951.236243-2-ulf.hansson@linaro.org
This commit is contained in:
Ulf Hansson 2024-01-30 13:39:47 +01:00
parent 697624ee8a
commit 161e16a5e5
2 changed files with 172 additions and 0 deletions
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134
drivers/base/power/common.c
View File

@ -167,6 +167,115 @@ struct device *dev_pm_domain_attach_by_name(struct device *dev,
}
EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name);
/**
* dev_pm_domain_attach_list - Associate a device with its PM domains.
* @dev: The device used to lookup the PM domains for.
* @data: The data used for attaching to the PM domains.
* @list: An out-parameter with an allocated list of attached PM domains.
*
* This function helps to attach a device to its multiple PM domains. The
* caller, which is typically a driver's probe function, may provide a list of
* names for the PM domains that we should try to attach the device to, but it
* may also provide an empty list, in case the attach should be done for all of
* the available PM domains.
*
* Callers must ensure proper synchronization of this function with power
* management callbacks.
*
* Returns the number of attached PM domains or a negative error code in case of
* a failure. Note that, to detach the list of PM domains, the driver shall call
* dev_pm_domain_detach_list(), typically during the remove phase.
*/
int dev_pm_domain_attach_list(struct device *dev,
const struct dev_pm_domain_attach_data *data,
struct dev_pm_domain_list **list)
{
struct device_node *np = dev->of_node;
struct dev_pm_domain_list *pds;
struct device *pd_dev = NULL;
int ret, i, num_pds = 0;
bool by_id = true;
u32 pd_flags = data ? data->pd_flags : 0;
u32 link_flags = pd_flags & PD_FLAG_NO_DEV_LINK ? 0 :
DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME;
if (dev->pm_domain)
return -EEXIST;
/* For now this is limited to OF based platforms. */
if (!np)
return 0;
if (data && data->pd_names) {
num_pds = data->num_pd_names;
by_id = false;
} else {
num_pds = of_count_phandle_with_args(np, "power-domains",
"#power-domain-cells");
}
if (num_pds <= 0)
return 0;
pds = devm_kzalloc(dev, sizeof(*pds), GFP_KERNEL);
if (!pds)
return -ENOMEM;
pds->pd_devs = devm_kcalloc(dev, num_pds, sizeof(*pds->pd_devs),
GFP_KERNEL);
if (!pds->pd_devs)
return -ENOMEM;
pds->pd_links = devm_kcalloc(dev, num_pds, sizeof(*pds->pd_links),
GFP_KERNEL);
if (!pds->pd_links)
return -ENOMEM;
if (link_flags && pd_flags & PD_FLAG_DEV_LINK_ON)
link_flags |= DL_FLAG_RPM_ACTIVE;
for (i = 0; i < num_pds; i++) {
if (by_id)
pd_dev = dev_pm_domain_attach_by_id(dev, i);
else
pd_dev = dev_pm_domain_attach_by_name(dev,
data->pd_names[i]);
if (IS_ERR_OR_NULL(pd_dev)) {
ret = pd_dev ? PTR_ERR(pd_dev) : -ENODEV;
goto err_attach;
}
if (link_flags) {
struct device_link *link;
link = device_link_add(dev, pd_dev, link_flags);
if (!link) {
ret = -ENODEV;
goto err_link;
}
pds->pd_links[i] = link;
}
pds->pd_devs[i] = pd_dev;
}
pds->num_pds = num_pds;
*list = pds;
return num_pds;
err_link:
dev_pm_domain_detach(pd_dev, true);
err_attach:
while (--i >= 0) {
if (pds->pd_links[i])
device_link_del(pds->pd_links[i]);
dev_pm_domain_detach(pds->pd_devs[i], true);
}
return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_domain_attach_list);
/**
* dev_pm_domain_detach - Detach a device from its PM domain.
* @dev: Device to detach.
@ -187,6 +296,31 @@ void dev_pm_domain_detach(struct device *dev, bool power_off)
}
EXPORT_SYMBOL_GPL(dev_pm_domain_detach);
/**
* dev_pm_domain_detach_list - Detach a list of PM domains.
* @list: The list of PM domains to detach.
*
* This function reverse the actions from dev_pm_domain_attach_list().
* Typically it should be invoked during the remove phase from drivers.
*
* Callers must ensure proper synchronization of this function with power
* management callbacks.
*/
void dev_pm_domain_detach_list(struct dev_pm_domain_list *list)
{
int i;
if (!list)
return;
for (i = 0; i < list->num_pds; i++) {
if (list->pd_links[i])
device_link_del(list->pd_links[i]);
dev_pm_domain_detach(list->pd_devs[i], true);
}
}
EXPORT_SYMBOL_GPL(dev_pm_domain_detach_list);
/**
* dev_pm_domain_start - Start the device through its PM domain.
* @dev: Device to start.

38
include/linux/pm_domain.h
View File

@ -19,6 +19,33 @@
#include <linux/cpumask.h>
#include <linux/time64.h>
/*
* Flags to control the behaviour when attaching a device to its PM domains.
*
* PD_FLAG_NO_DEV_LINK: As the default behaviour creates a device-link
* for every PM domain that gets attached, this
* flag can be used to skip that.
*
* PD_FLAG_DEV_LINK_ON: Add the DL_FLAG_RPM_ACTIVE to power-on the
* supplier and its PM domain when creating the
* device-links.
*
*/
#define PD_FLAG_NO_DEV_LINK BIT(0)
#define PD_FLAG_DEV_LINK_ON BIT(1)
struct dev_pm_domain_attach_data {
const char * const *pd_names;
const u32 num_pd_names;
const u32 pd_flags;
};
struct dev_pm_domain_list {
struct device **pd_devs;
struct device_link **pd_links;
u32 num_pds;
};
/*
* Flags to control the behaviour of a genpd.
*
@ -420,7 +447,11 @@ 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);
int dev_pm_domain_attach_list(struct device *dev,
const struct dev_pm_domain_attach_data *data,
struct dev_pm_domain_list **list);
void dev_pm_domain_detach(struct device *dev, bool power_off);
void dev_pm_domain_detach_list(struct dev_pm_domain_list *list);
int dev_pm_domain_start(struct device *dev);
void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd);
int dev_pm_domain_set_performance_state(struct device *dev, unsigned int state);
@ -439,7 +470,14 @@ static inline struct device *dev_pm_domain_attach_by_name(struct device *dev,
{
return NULL;
}
static inline int dev_pm_domain_attach_list(struct device *dev,
const struct dev_pm_domain_attach_data *data,
struct dev_pm_domain_list **list)
{
return 0;
}
static inline void dev_pm_domain_detach(struct device *dev, bool power_off) {}
static inline void dev_pm_domain_detach_list(struct dev_pm_domain_list *list) {}
static inline int dev_pm_domain_start(struct device *dev)
{
return 0;