From mboxrd@z Thu Jan 1 00:00:00 1970 From: jonathanh@nvidia.com (Jon Hunter) Date: Thu, 11 Aug 2016 17:39:54 +0100 Subject: [RFC PATCH 6/8] PM / Domains: Remove a provider by referencing the data pointer In-Reply-To: References: <1457090634-14785-1-git-send-email-jonathanh@nvidia.com> <1457090634-14785-7-git-send-email-jonathanh@nvidia.com> <5769455C.9010809@nvidia.com> Message-ID: <18ad702c-83fe-fd6d-89ae-57e6f2715860@nvidia.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 05/08/16 12:55, Ulf Hansson wrote: > On 21 June 2016 at 15:47, Jon Hunter wrote: >> >> On 15/06/16 15:38, Ulf Hansson wrote: >>> On 4 March 2016 at 12:23, Jon Hunter wrote: >>>> To remove a PM domain from the system, it is necessary to ensure >>>> that any PM domain providers associated with the PM domain have >>>> been removed. Otherwise it could be possible to obtain a pointer >>>> to a PM domain structure that has been removed. >>>> >>>> PM domains now have a reference to the pointer for the PM domain >>>> provider's data variable. Add a function so that a PM domain can >>>> remove a PM domain provider by referencing the data pointer. > > >>>> >>>> Signed-off-by: Jon Hunter >>>> --- >>>> drivers/base/power/domain.c | 24 ++++++++++++++++++++++++ >>>> include/linux/pm_domain.h | 2 ++ >>>> 2 files changed, 26 insertions(+) >>>> >>>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >>>> index 72055fef6256..438885f2455f 100644 >>>> --- a/drivers/base/power/domain.c >>>> +++ b/drivers/base/power/domain.c >>>> @@ -1738,6 +1738,30 @@ void of_genpd_del_provider(struct device_node *np) >>>> EXPORT_SYMBOL_GPL(of_genpd_del_provider); >>>> >>>> /** >>>> + * of_genpd_del_provider_by_data() - Remove a registered PM domain provider >>>> + * @data: Pointer to the data associated with the PM domain provider >>>> + * >>>> + * Look up a PM domain provider based upon a pointer to it's data and >>>> + * remove the PM domain provider from the list of providers. >>>> + */ >>>> +void of_genpd_del_provider_by_data(void *data) >>>> +{ >>>> + struct of_genpd_provider *c, *cp; >>>> + >>>> + mutex_lock(&of_genpd_mutex); >>>> + list_for_each_entry_safe(cp, c, &of_genpd_providers, link) { >>>> + if (cp->data == data) { >>>> + list_del(&cp->link); >>>> + of_node_put(cp->node); >>>> + kfree(cp); >>>> + break; >>>> + } >>>> + } >>>> + mutex_unlock(&of_genpd_mutex); >>>> +} >>>> +EXPORT_SYMBOL_GPL(of_genpd_del_provider_by_data); >>>> + >>>> +/** >>>> * of_genpd_get_from_provider() - Look-up PM domain >>>> * @genpdspec: OF phandle args to use for look-up >>>> * >>>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h >>>> index bed84413546f..7b7921a65cb0 100644 >>>> --- a/include/linux/pm_domain.h >>>> +++ b/include/linux/pm_domain.h >>>> @@ -199,6 +199,7 @@ int of_genpd_add_provider_simple(struct device_node *np, >>>> int of_genpd_add_provider_onecell(struct device_node *np, >>>> struct genpd_onecell_data *data); >>>> void of_genpd_del_provider(struct device_node *np); >>> >>> There's currently only one user of of_genpd_del_provider(). >>> >>> Could this patch just convert that user to the new API, so we don't >>> need to keep both the legacy and new one? >>> >>> I guess we could then just stick to the name "of_genpd_del_provider()". >> >> I had a look at this and to do that we would end up with >> of_genpd_del_provider(struct device_node *np, void *data) where the user >> should only pass one of the arguments. It seems a bit odd. However, >> unless I have forgotten something, I wonder if we should just make >> of_genpd_del_provider_by_name() a local function and not export this at >> all? It seems more natural for users to delete a provider by the >> device_node than by name rather than the data argument. >> >> The only problem I see with making of_genpd_del_provider_by_name() local >> is that I need to add a prototype for the function at the top of the >> domain.c source file so that it builds because __pm_genpd_remove() is >> defined above it. Yes I could move __pm_genpd_remove() to the bottom of >> the file but then it is not located next to pm_genpd_init() which seems odd. >> >> Let me know what you think. > > Sorry for delay! I have now looked into this in more detail. No problem. Thanks! > When an genpd provider is added today, it's supposed to get a > corresponding *unique* OF device node associated with it, right!? > > If we store this OF device node from the provider in the struct > generic_pm_domain, instead of the "provider_data pointer", we wouldn't > need to the add of_genpd_del_provider_by_data() at all. Because we can > use the currently available of_genpd_del_provider(), right!? > > Or what am I missing? :-) No that would work as well. I guess I was trying to make it non-DT specific. However, for now it can be to simplify matters and it could always be extended later if necessary. I am also thinking about making pm_genpd_remove_tail() of_genpd_remove_tail() as it seems silly to have both a struct device pointer and a struct device_node pointer stored for the provider. Cheers Jon -- nvpublic