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[82.243.161.21]) by smtp.gmail.com with ESMTPSA id w22sm347094wmk.34.2019.12.02.10.59.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Dec 2019 10:59:25 -0800 (PST) References: <20191129161658.344517-1-jbrunet@baylibre.com> <20191202181923.4D26D20717@mail.kernel.org> User-agent: mu4e 1.3.3; emacs 26.2 From: Jerome Brunet To: Stephen Boyd , Michael Turquette Cc: Kevin Hilman , linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org Subject: Re: [PATCH] clk: walk orphan list on clock provider registration In-reply-to: <20191202181923.4D26D20717@mail.kernel.org> Date: Mon, 02 Dec 2019 19:59:22 +0100 Message-ID: <1j7e3eft9x.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On Mon 02 Dec 2019 at 19:19, Stephen Boyd wrote: > Quoting Jerome Brunet (2019-11-29 08:16:58) >> So far, we walked the orphan list every time a new clock was registered >> in CCF. This was fine since the clocks were only referenced by name. >> >> Now that the clock can be referenced through DT, it is not enough: >> * Controller A register first a reference clocks from controller B >> through DT. >> * Controller B register all its clocks then register the provider. >> >> Each time controller B registers a new clock, the orphan list is walked >> but it can't match since the provider is registered yet. When the >> provider is finally registered, the orphan list is not walked unless >> another clock is registered afterward. >> >> This can lead to situation where some clocks remain orphaned even if >> the parent is available. >> >> Walking the orphan list on provider registration solves the problem. >> >> Fixes: fc0c209c147f ("clk: Allow parents to be specified without string names") >> Signed-off-by: Jerome Brunet >> --- > > Sounds right. Thanks for making the fix! > > I suspect there should be a reported-by tag though? laboriously, yes > >> drivers/clk/clk.c | 59 +++++++++++++++++++++++++++++------------------ >> 1 file changed, 37 insertions(+), 22 deletions(-) >> >> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c >> index ef4416721777..917ba37c3b9d 100644 >> --- a/drivers/clk/clk.c >> +++ b/drivers/clk/clk.c >> @@ -3249,6 +3249,34 @@ static inline void clk_debug_unregister(struct clk_core *core) >> } >> #endif >> >> +static void __clk_core_reparent_orphan(void) > > Maybe drop the double underscore. clk_core prefix already means "private > to this file". I've done it this way just to keep coherent with __clk_core_init(), which the code was extracted from In the end, I don't mind so I'll drop it in the v2 > >> +{ >> + struct clk_core *orphan; >> + struct hlist_node *tmp2; >> + >> + /* >> + * walk the list of orphan clocks and reparent any that newly finds a >> + * parent. >> + */ >> + hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { >> + struct clk_core *parent = __clk_init_parent(orphan); >> + >> + /* >> + * We need to use __clk_set_parent_before() and _after() to >> + * to properly migrate any prepare/enable count of the orphan >> + * clock. This is important for CLK_IS_CRITICAL clocks, which >> + * are enabled during init but might not have a parent yet. >> + */ >> + if (parent) { >> + /* update the clk tree topology */ >> + __clk_set_parent_before(orphan, parent); >> + __clk_set_parent_after(orphan, parent, NULL); >> + __clk_recalc_accuracies(orphan); >> + __clk_recalc_rates(orphan, 0); >> + } >> + } >> +} >> + >> /** >> * __clk_core_init - initialize the data structures in a struct clk_core >> * @core: clk_core being initialized >> @@ -3259,8 +3287,6 @@ static inline void clk_debug_unregister(struct clk_core *core) >> static int __clk_core_init(struct clk_core *core) >> { >> int ret; >> - struct clk_core *orphan; >> - struct hlist_node *tmp2; >> unsigned long rate; >> >> if (!core) >> @@ -3416,27 +3442,8 @@ static int __clk_core_init(struct clk_core *core) >> clk_enable_unlock(flags); >> } >> >> - /* >> - * walk the list of orphan clocks and reparent any that newly finds a >> - * parent. >> - */ >> - hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) { >> - struct clk_core *parent = __clk_init_parent(orphan); >> + __clk_core_reparent_orphan(); >> >> - /* >> - * We need to use __clk_set_parent_before() and _after() to >> - * to properly migrate any prepare/enable count of the orphan >> - * clock. This is important for CLK_IS_CRITICAL clocks, which >> - * are enabled during init but might not have a parent yet. >> - */ >> - if (parent) { >> - /* update the clk tree topology */ >> - __clk_set_parent_before(orphan, parent); >> - __clk_set_parent_after(orphan, parent, NULL); >> - __clk_recalc_accuracies(orphan); >> - __clk_recalc_rates(orphan, 0); >> - } >> - } >> >> kref_init(&core->ref); >> out: >> @@ -4288,6 +4295,10 @@ int of_clk_add_provider(struct device_node *np, >> mutex_unlock(&of_clk_mutex); >> pr_debug("Added clock from %pOF\n", np); >> >> + clk_prepare_lock(); >> + __clk_core_reparent_orphan(); >> + clk_prepare_unlock(); >> + > > Maybe make a locked version of this function and an unlocked version? > >> ret = of_clk_set_defaults(np, true); >> if (ret < 0) >> of_clk_del_provider(np); >> @@ -4323,6 +4334,10 @@ int of_clk_add_hw_provider(struct device_node *np, >> mutex_unlock(&of_clk_mutex); >> pr_debug("Added clk_hw provider from %pOF\n", np); >> >> + clk_prepare_lock(); >> + __clk_core_reparent_orphan(); >> + clk_prepare_unlock(); >> + > > So we don't duplicate this twice. > Sure. >> ret = of_clk_set_defaults(np, true); >> if (ret < 0)