Quoting Jerome Brunet (2018-06-19 06:40:51) > CLK_SET_RATE_GATE should prevent any operation which may result in a rate > change or glitch while the clock is prepared/enabled. > > IOW, the following sequence is not allowed anymore with CLK_SET_RATE_GATE: > * clk_get() > * clk_prepare_enable() > * clk_get_rate() > * clk_set_rate() > > At the moment this is enforced on the leaf clock of the operation, not > along the tree. This problematic because, if a PLL has the CLK_RATE_GATE, > it won't be enforced if the clk_set_rate() is called on its child clocks. > > Using clock rate protection, we can now enforce CLK_SET_RATE_GATE along the > clock tree > > Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > Tested-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx> > Tested-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx> Applied to clk-core-set-rate-gate. Thanks, Mike > --- > drivers/clk/clk.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index 9760b526ca31..97c09243fb21 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -691,6 +691,9 @@ static void clk_core_unprepare(struct clk_core *core) > "Unpreparing critical %s\n", core->name)) > return; > > + if (core->flags & CLK_SET_RATE_GATE) > + clk_core_rate_unprotect(core); > + > if (--core->prepare_count > 0) > return; > > @@ -765,6 +768,16 @@ static int clk_core_prepare(struct clk_core *core) > > core->prepare_count++; > > + /* > + * CLK_SET_RATE_GATE is a special case of clock protection > + * Instead of a consumer claiming exclusive rate control, it is > + * actually the provider which prevents any consumer from making any > + * operation which could result in a rate change or rate glitch while > + * the clock is prepared. > + */ > + if (core->flags & CLK_SET_RATE_GATE) > + clk_core_rate_protect(core); > + > return 0; > unprepare: > clk_core_unprepare(core->parent); > @@ -1888,9 +1901,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core, > if (clk_core_rate_is_protected(core)) > return -EBUSY; > > - if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count) > - return -EBUSY; > - > /* calculate new rates and get the topmost changed clock */ > top = clk_calc_new_rates(core, req_rate); > if (!top) > -- > 2.14.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
