On 15/06/16 15:33, Ulf Hansson wrote:
> On 4 March 2016 at 12:23, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
>> The genpd framework allows users to add PM domains via the pm_genpd_init()
>> function, however, there is no corresponding function to remove a PM
>> domain. For most devices this may be fine as the PM domains are never
>> removed, however, for devices that wish to populate the PM domains from
>> within a driver, having the ability to remove a PM domain if the probing
>> of the device fails or the driver is unloaded is necessary.
>>
>> Add the function pm_genpd_remove() to remove a PM domain by referencing
>> it's generic_pm_domain structure.
>>
>> If a device supports nested or subdomains, then the PM domains
>> should be removed in reverse order to ensure that the subdomains are
>> removed first. Hence, add the function pm_genpd_remove_tail() to remove
>> the last PM domain added by a given provider and return the
>> generic_pm_domain structure for the PM domain that was removed.
>
> Perhaps split this up, so the pm_genpd_remove_tail() gets added in a
> separate patch on top.
OK.
>>
>> PM domains can only be removed if they are not a parent domain to
>> another PM domain and have no devices associated with them.
>>
>> When removing PM domains, the PM domain will also be removed from the
>> list of providers, if it was registered.
>>
>> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
>> ---
>> drivers/base/power/domain.c | 96 +++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/pm_domain.h | 12 ++++++
>> 2 files changed, 108 insertions(+)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index 9b33377bf01b..17090e1c91d6 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -1556,6 +1556,102 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
>> }
>> EXPORT_SYMBOL_GPL(pm_genpd_init);
>>
>> +/**
>> + * __pm_genpd_remove - Remove a generic I/O PM domain
>> + * @genpd: Pointer to PM domain that is to be removed.
>> + *
>> + * To remove the PM domain, this function:
>> + * - Removes the PM domain from the list of providers, if registered.
>> + * - Removes the PM domain as a subdomain to any parent domains,
>> + * if it was added.
>> + * - Removes the PM domain from the list of registered PM domains.
>> + *
>> + * The PM domain will only be removed, if it is not a parent to any
>> + * other PM domain and has no devices associated with it. Must be called
>> + * with the gpd_list_lock held.
>> + */
>> +static int __pm_genpd_remove(struct generic_pm_domain *genpd)
>
> Please rename to genpd_remove() as it's a static function.
OK.
>> +{
>> + struct gpd_link *l, *link;
>> + int ret = 0;
>> +
>> + if (IS_ERR_OR_NULL(genpd))
>> + return -EINVAL;
>> +
>> + if (genpd->provider_data)
>> + of_genpd_del_provider_by_data(genpd->provider_data);
>> +
>> + mutex_lock(&genpd->lock);
>> +
>> + if (!list_empty(&genpd->master_links) || genpd->device_count) {
>> + mutex_unlock(&genpd->lock);
>> + pr_err("%s: unable to remove %s\n", __func__, genpd->name);
>> + return -EBUSY;
>> + }
>> +
>> + list_for_each_entry_safe(link, l, &genpd->slave_links, slave_node) {
>> + list_del(&link->master_node);
>> + list_del(&link->slave_node);
>> + kfree(link);
>> + }
>> +
>> + list_del(&genpd->gpd_list_node);
>> + mutex_unlock(&genpd->lock);
>> + cancel_work_sync(&genpd->power_off_work);
>> + pr_debug("%s: removed %s\n", __func__, genpd->name);
>> +
>> + return ret;
>> +}
>> +
>> +/**
>> + * pm_genpd_remove - Remove a generic I/O PM domain
>> + * @genpd: Pointer to PM domain that is to be removed.
>> + */
>> +int pm_genpd_remove(struct generic_pm_domain *genpd)
>> +{
>> + int ret;
>> +
>> + mutex_lock(&gpd_list_lock);
>> + ret = __pm_genpd_remove(genpd);
>> + mutex_unlock(&gpd_list_lock);
>> +
>> + return ret;
>> +}
>> +
>> +/**
>> + * pm_genpd_remove_tail - Remove the last PM domain registered for a provider
>> + * @provider: Pointer to device structure associated with provider
>> + *
>> + * Find the last PM domain that was added by the provider whose 'provider'
>> + * device structure matches the device structure given. The 'provider'
>> + * device structure for a given PM domain should be initialised by the
>> + * device that is creating the PM domains and hence, calling
>> + * pm_genpd_init().
>
> Maybe make this a bigger "Important note" as what is needed to
> actually benefit from using this function.
Yes, good point. Will update.
Cheers
Jon
--
nvpublic
--
To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
