From 4ec4cfbf63a697a5b1c82b400d28afd0347d555a Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 8 Apr 2022 10:06:11 +0200 Subject: [PATCH] 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 # imx8mp Tested-by: Marek Szyprowski # exynos4210, meson g12b Signed-off-by: Maxime Ripard --- drivers/clk/clk.c | 6 +++++- drivers/clk/clk_test.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 1 deletion(-) --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2469,6 +2469,10 @@ static int clk_set_rate_range_nolock(str 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 @@ -2486,7 +2490,7 @@ static int clk_set_rate_range_nolock(str * - 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 */ --- a/drivers/clk/clk_test.c +++ b/drivers/clk/clk_test.c @@ -362,9 +362,37 @@ static void clk_test_uncached_set_range( KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2); } +/* + * 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 = hw->clk; + unsigned long rate; + + 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); +} + 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), {} };