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clk: Take into account uncached clocks in clk_set_rate_range()

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clk_set_rate_range() will use the last requested rate for the clock when
it calls into the driver set_rate hook.

However, if CLK_GET_RATE_NOCACHE is set on that clock, the last
requested rate might not be matching the current rate of the clock. In
such a case, let's read out the rate from the hardware and use that in
our set_rate instead.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-13-maxime@cerno.tech
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Maxime Ripard 2022-08-16 13:25:17 +02:00 committed by Stephen Boyd
parent 2e9cad1abc
commit 3afb07231d
2 changed files with 36 additions and 1 deletions
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6
drivers/clk/clk.c
View file

@ -2373,6 +2373,10 @@ static int clk_set_rate_range_nolock(struct clk *clk,
goto out;
}
rate = clk->core->req_rate;
if (clk->core->flags & CLK_GET_RATE_NOCACHE)
rate = clk_core_get_rate_recalc(clk->core);
/*
* Since the boundaries have been changed, let's give the
* opportunity to the provider to adjust the clock rate based on
@ -2390,7 +2394,7 @@ static int clk_set_rate_range_nolock(struct clk *clk,
* - the determine_rate() callback does not really check for
* this corner case when determining the rate
*/
rate = clamp(clk->core->req_rate, min, max);
rate = clamp(rate, min, max);
ret = clk_core_set_rate_nolock(clk->core, rate);
if (ret) {
/* rollback the changes */

31
drivers/clk/clk_test.c
View file

@ -375,9 +375,40 @@ static void clk_test_uncached_set_range(struct kunit *test)
clk_put(clk);
}
/*
* Test that for an uncached clock, clk_set_rate_range() will work
* properly if the rate has changed in hardware.
*
* In this case, it means that if the rate wasn't initially in the range
* we're trying to set, but got changed at some point into the range
* without the kernel knowing about it, its rate shouldn't be affected.
*/
static void clk_test_uncached_updated_rate_set_range(struct kunit *test)
{
struct clk_dummy_context *ctx = test->priv;
struct clk_hw *hw = &ctx->hw;
struct clk *clk = clk_hw_get_clk(hw, NULL);
unsigned long rate;
/* We change the rate behind the clock framework's back */
ctx->rate = DUMMY_CLOCK_RATE_1 + 1000;
KUNIT_ASSERT_EQ(test,
clk_set_rate_range(clk,
DUMMY_CLOCK_RATE_1,
DUMMY_CLOCK_RATE_2),
0);
rate = clk_get_rate(clk);
KUNIT_ASSERT_GT(test, rate, 0);
KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1 + 1000);
clk_put(clk);
}
static struct kunit_case clk_uncached_test_cases[] = {
KUNIT_CASE(clk_test_uncached_get_rate),
KUNIT_CASE(clk_test_uncached_set_range),
KUNIT_CASE(clk_test_uncached_updated_rate_set_range),
{}
};