[RESEND PATCH 1/3] clk: Remove _clk_reparent from API and restructure code
Ulf Hansson
ulf.hansson at linaro.org
Wed Mar 20 16:39:28 EDT 2013
On 20 March 2013 16:03, Mike Turquette <mturquette at linaro.org> wrote:
> Quoting Rajendra Nayak (2013-03-20 03:13:36)
>> On Wednesday 20 March 2013 03:15 PM, Ulf Hansson wrote:
>> > On 19 March 2013 22:20, Mike Turquette <mturquette at linaro.org> wrote:
>> >> Quoting Ulf Hansson (2013-03-12 12:20:48)
>> >>> From: Ulf Hansson <ulf.hansson at linaro.org>
>> >>>
>> >>> There shall be no reason for keeping this API available for clock
>> >>> providers. So we remove it from the API and restrcuture the code so
>> >>> for example the COMMON_CLK_DEBUG part is separated.
>> >>>
>> >>
>> >> Hi Ulf,
>> >>
>> >> There is one reason to keep this api. OMAP currently uses it to change
>> >> the parent of a PLL during .set_rate. This is kind of a legacy
>> >> mechanism however, and the reentrancy series I posted actually takes
>> >> care of this one corner case:
>> >> http://article.gmane.org/gmane.linux.kernel/1448449
>> >
>> > Hi Mike,
>> >
>> > It was a while ago I created this patch, so I guess this has beed
>> > merged without me noticing, sorry.
>> >
>> >>
>> >> Let me see how the OMAP folks feel about taking that patch in, which
>> >> eliminates the only external user of the API. +Rajendra & Benoit
>> >>
>> >
>> > I have no problem rebasing the patch and keep the API, if that is the
>> > easiest way forward.
>>
>> Ulf, It would be good if you could keep the api for now. I seemed to have
>> missed out on Mikes patch getting rid of the the api from OMAP PLL .set_rate.
>> I will take a stab at that to get rid of that api along with the other OMAP
>> only things that exist today as part of Common clk.
>>
>
> Rajendra,
>
> Yeah, the patch I linked to above was actually just "example code"
> showing how to reentrantly call clk_set_parent from within a .set_rate
> callback. It's no suprise you missed it since the patch $SUBJECT starts
> with "HACK:" ;-)
>
> The trick is to recognize that OMAP's PLLs are mux clocks and have them
> properly support clk_set_parent. This would have made my life easier in
> the bad days of DPLL cascading back in 2011.
>
>> regards,
>> Rajendra
>>
>> > Although, I guess in the end you want to remove these kind of internal
>> > clk API functions. So, if we get ack from Rajendra & Benoit, it is
>> > better to remove the API right?
>> >
>
> Ulf,
>
> Correct, as we discussed at LCA I do want to get rid of all of these
> internal accessor functions.
>
> Thanks,
> Mike
>
Thanks for your responses. I will send a new version which keeps the
API for now.
Kind regards
Uffe
>> > Kind regards
>> > Ulf Hansson
>> >
>> >> Thanks,
>> >> Mike
>> >>
>> >>> This patch will also make it possible to hold the spinlock over the
>> >>> actual update of the clock tree topology, which could not be done
>> >>> before when both debugfs updates and clock rate updates was done
>> >>> within the same function.
>> >>>
>> >>> Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
>> >>> ---
>> >>> drivers/clk/clk.c | 82 ++++++++++++++++++++++++------------------
>> >>> include/linux/clk-provider.h | 1 -
>> >>> 2 files changed, 48 insertions(+), 35 deletions(-)
>> >>>
>> >>> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
>> >>> index 593a2e4..2e10cc1 100644
>> >>> --- a/drivers/clk/clk.c
>> >>> +++ b/drivers/clk/clk.c
>> >>> @@ -284,6 +284,39 @@ out:
>> >>> }
>> >>>
>> >>> /**
>> >>> + * clk_debug_reparent - reparent clk node in the debugfs clk tree
>> >>> + * @clk: the clk being reparented
>> >>> + * @new_parent: the new clk parent, may be NULL
>> >>> + *
>> >>> + * Rename clk entry in the debugfs clk tree if debugfs has been
>> >>> + * initialized. Otherwise it bails out early since the debugfs clk tree
>> >>> + * will be created lazily by clk_debug_init as part of a late_initcall.
>> >>> + *
>> >>> + * Caller must hold prepare_lock.
>> >>> + */
>> >>> +static void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
>> >>> +{
>> >>> + struct dentry *d;
>> >>> + struct dentry *new_parent_d;
>> >>> +
>> >>> + if (!inited)
>> >>> + return;
>> >>> +
>> >>> + if (new_parent)
>> >>> + new_parent_d = new_parent->dentry;
>> >>> + else
>> >>> + new_parent_d = orphandir;
>> >>> +
>> >>> + d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
>> >>> + new_parent_d, clk->name);
>> >>> + if (d)
>> >>> + clk->dentry = d;
>> >>> + else
>> >>> + pr_debug("%s: failed to rename debugfs entry for %s\n",
>> >>> + __func__, clk->name);
>> >>> +}
>> >>> +
>> >>> +/**
>> >>> * clk_debug_init - lazily create the debugfs clk tree visualization
>> >>> *
>> >>> * clks are often initialized very early during boot before memory can
>> >>> @@ -338,6 +371,9 @@ static int __init clk_debug_init(void)
>> >>> late_initcall(clk_debug_init);
>> >>> #else
>> >>> static inline int clk_debug_register(struct clk *clk) { return 0; }
>> >>> +static inline void clk_debug_reparent(struct clk *clk, struct clk *new_parent)
>> >>> +{
>> >>> +}
>> >>> #endif
>> >>>
>> >>> /* caller must hold prepare_lock */
>> >>> @@ -1179,16 +1215,8 @@ out:
>> >>> return ret;
>> >>> }
>> >>>
>> >>> -void __clk_reparent(struct clk *clk, struct clk *new_parent)
>> >>> +static void clk_reparent(struct clk *clk, struct clk *new_parent)
>> >>> {
>> >>> -#ifdef CONFIG_COMMON_CLK_DEBUG
>> >>> - struct dentry *d;
>> >>> - struct dentry *new_parent_d;
>> >>> -#endif
>> >>> -
>> >>> - if (!clk || !new_parent)
>> >>> - return;
>> >>> -
>> >>> hlist_del(&clk->child_node);
>> >>>
>> >>> if (new_parent)
>> >>> @@ -1196,28 +1224,7 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent)
>> >>> else
>> >>> hlist_add_head(&clk->child_node, &clk_orphan_list);
>> >>>
>> >>> -#ifdef CONFIG_COMMON_CLK_DEBUG
>> >>> - if (!inited)
>> >>> - goto out;
>> >>> -
>> >>> - if (new_parent)
>> >>> - new_parent_d = new_parent->dentry;
>> >>> - else
>> >>> - new_parent_d = orphandir;
>> >>> -
>> >>> - d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
>> >>> - new_parent_d, clk->name);
>> >>> - if (d)
>> >>> - clk->dentry = d;
>> >>> - else
>> >>> - pr_debug("%s: failed to rename debugfs entry for %s\n",
>> >>> - __func__, clk->name);
>> >>> -out:
>> >>> -#endif
>> >>> -
>> >>> clk->parent = new_parent;
>> >>> -
>> >>> - __clk_recalc_rates(clk, POST_RATE_CHANGE);
>> >>> }
>> >>>
>> >>> static int __clk_set_parent(struct clk *clk, struct clk *parent)
>> >>> @@ -1329,7 +1336,9 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
>> >>> }
>> >>>
>> >>> /* propagate rate recalculation downstream */
>> >>> - __clk_reparent(clk, parent);
>> >>> + clk_reparent(clk, parent);
>> >>> + clk_debug_reparent(clk, parent);
>> >>> + __clk_recalc_rates(clk, POST_RATE_CHANGE);
>> >>>
>> >>> out:
>> >>> mutex_unlock(&prepare_lock);
>> >>> @@ -1453,14 +1462,19 @@ int __clk_init(struct device *dev, struct clk *clk)
>> >>> hlist_for_each_entry_safe(orphan, tmp, tmp2, &clk_orphan_list, child_node) {
>> >>> if (orphan->ops->get_parent) {
>> >>> i = orphan->ops->get_parent(orphan->hw);
>> >>> - if (!strcmp(clk->name, orphan->parent_names[i]))
>> >>> - __clk_reparent(orphan, clk);
>> >>> + if (!strcmp(clk->name, orphan->parent_names[i])) {
>> >>> + clk_reparent(orphan, clk);
>> >>> + clk_debug_reparent(orphan, clk);
>> >>> + __clk_recalc_rates(orphan, POST_RATE_CHANGE);
>> >>> + }
>> >>> continue;
>> >>> }
>> >>>
>> >>> for (i = 0; i < orphan->num_parents; i++)
>> >>> if (!strcmp(clk->name, orphan->parent_names[i])) {
>> >>> - __clk_reparent(orphan, clk);
>> >>> + clk_reparent(orphan, clk);
>> >>> + clk_debug_reparent(orphan, clk);
>> >>> + __clk_recalc_rates(orphan, POST_RATE_CHANGE);
>> >>> break;
>> >>> }
>> >>> }
>> >>> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
>> >>> index 4989b8a..87a7c2c 100644
>> >>> --- a/include/linux/clk-provider.h
>> >>> +++ b/include/linux/clk-provider.h
>> >>> @@ -359,7 +359,6 @@ struct clk *__clk_lookup(const char *name);
>> >>> */
>> >>> int __clk_prepare(struct clk *clk);
>> >>> void __clk_unprepare(struct clk *clk);
>> >>> -void __clk_reparent(struct clk *clk, struct clk *new_parent);
>> >>> unsigned long __clk_round_rate(struct clk *clk, unsigned long rate);
>> >>>
>> >>> struct of_device_id;
>> >>> --
>> >>> 1.7.10
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