[PATCH v2 01/11] clk: take the prepare lock out of clk_core_set_parent

[jbrunet@baylibre.com (Jerome Brunet)]

On Thu, 2017-05-25 at 11:54 -0700, Michael Turquette wrote:
> Quoting Jerome Brunet (2017-05-21 14:59:48)
> > 
> > Rework set_parent core function so it can be called when the prepare lock
> > is already held by the caller.
> > 
> > This rework is done to ease the integration of the "protected" clock
> > functionality.
> > 
> > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> 
> Applied to clk-next-protect for testing.
> 

Noted, I'll base the v3 on top of this branch

> Regards,
> Mike
> 
> > ---
> > ?drivers/clk/clk.c | 39 ++++++++++++++++++---------------------
> > ?1 file changed, 18 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index fc58c52a26b4..f5c371532509 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -1787,7 +1787,8 @@ bool clk_has_parent(struct clk *clk, struct clk
> > *parent)
> > ?}
> > ?EXPORT_SYMBOL_GPL(clk_has_parent);
> > ?
> > -static int clk_core_set_parent(struct clk_core *core, struct clk_core
> > *parent)
> > +static int clk_core_set_parent_nolock(struct clk_core *core,
> > +?????????????????????????????????????struct clk_core *parent)
> > ?{
> > ????????int ret = 0;
> > ????????int p_index = 0;
> > @@ -1796,23 +1797,16 @@ static int clk_core_set_parent(struct clk_core
> > *core, struct clk_core *parent)
> > ????????if (!core)
> > ????????????????return 0;
> > ?
> > -???????/* prevent racing with updates to the clock topology */
> > -???????clk_prepare_lock();
> > -
> > ????????if (core->parent == parent)
> > -???????????????goto out;
> > +???????????????return 0;
> > ?
> > ????????/* verify ops for for multi-parent clks */
> > -???????if ((core->num_parents > 1) && (!core->ops->set_parent)) {
> > -???????????????ret = -ENOSYS;
> > -???????????????goto out;
> > -???????}
> > +???????if ((core->num_parents > 1) && (!core->ops->set_parent))
> > +???????????????return -ENOSYS;
> > ?
> > ????????/* check that we are allowed to re-parent if the clock is in use */
> > -???????if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count) {
> > -???????????????ret = -EBUSY;
> > -???????????????goto out;
> > -???????}
> > +???????if ((core->flags & CLK_SET_PARENT_GATE) && core->prepare_count)
> > +???????????????return -EBUSY;
> > ?
> > ????????/* try finding the new parent index */
> > ????????if (parent) {
> > @@ -1820,8 +1814,7 @@ static int clk_core_set_parent(struct clk_core *core,
> > struct clk_core *parent)
> > ????????????????if (p_index < 0) {
> > ????????????????????????pr_debug("%s: clk %s can not be parent of clk %s\n",
> > ????????????????????????????????????????__func__, parent->name, core->name);
> > -???????????????????????ret = p_index;
> > -???????????????????????goto out;
> > +???????????????????????return p_index;
> > ????????????????}
> > ????????????????p_rate = parent->rate;
> > ????????}
> > @@ -1831,7 +1824,7 @@ static int clk_core_set_parent(struct clk_core *core,
> > struct clk_core *parent)
> > ?
> > ????????/* abort if a driver objects */
> > ????????if (ret & NOTIFY_STOP_MASK)
> > -???????????????goto out;
> > +???????????????return ret;
> > ?
> > ????????/* do the re-parent */
> > ????????ret = __clk_set_parent(core, parent, p_index);
> > @@ -1844,9 +1837,6 @@ static int clk_core_set_parent(struct clk_core *core,
> > struct clk_core *parent)
> > ????????????????__clk_recalc_accuracies(core);
> > ????????}
> > ?
> > -out:
> > -???????clk_prepare_unlock();
> > -
> > ????????return ret;
> > ?}
> > ?
> > @@ -1869,10 +1859,17 @@ static int clk_core_set_parent(struct clk_core
> > *core, struct clk_core *parent)
> > ? */
> > ?int clk_set_parent(struct clk *clk, struct clk *parent)
> > ?{
> > +???????int ret;
> > +
> > ????????if (!clk)
> > ????????????????return 0;
> > ?
> > -???????return clk_core_set_parent(clk->core, parent ? parent->core : NULL);
> > +???????clk_prepare_lock();
> > +???????ret = clk_core_set_parent_nolock(clk->core,
> > +????????????????????????????????????????parent ? parent->core : NULL);
> > +???????clk_prepare_unlock();
> > +
> > +???????return ret;
> > ?}
> > ?EXPORT_SYMBOL_GPL(clk_set_parent);
> > ?
> > @@ -2753,7 +2750,7 @@ void clk_unregister(struct clk *clk)
> > ????????????????/* Reparent all children to the orphan list. */
> > ????????????????hlist_for_each_entry_safe(child, t, &clk->core->children,
> > ??????????????????????????????????????????child_node)
> > -???????????????????????clk_core_set_parent(child, NULL);
> > +???????????????????????clk_core_set_parent_nolock(child, NULL);
> > ????????}
> > ?
> > ????????hlist_del_init(&clk->core->child_node);
> > --?
> > 2.9.4
> >