Commit 3afb0723 authored by Maxime Ripard's avatar Maxime Ripard Committed by Stephen Boyd
Browse files

clk: Take into account uncached clocks in clk_set_rate_range() 



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: default avatarMaxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-13-maxime@cerno.tech


Tested-by: default avatarLinux Kernel Functional Testing <lkft@linaro.org>
Tested-by: default avatarNaresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 2e9cad1a

drivers/clk/clk.c

+5 −1
Original line number Diff line number Diff line
@@ -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 */

drivers/clk/clk_test.c

+31 −0
Original line number Diff line number Diff line
@@ -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),

	{}

};