From 06f02ffffc5aa432e119d094f019ba97ccd8bb89 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 25 Mar 2022 17:11:44 +0100 Subject: [PATCH] clk: Drop the rate range on clk_put() When clk_put() is called we don't make another clk_set_rate() call to re-evaluate the rate boundaries. This is unlike clk_set_rate_range() that evaluates the rate again each time it is called. However, clk_put() is essentially equivalent to clk_set_rate_range() since after clk_put() completes the consumer's boundaries shouldn't be enforced anymore. Let's add a call to clk_set_rate_range() in clk_put() to make sure those rate boundaries are dropped and the clock provider drivers can react. In order to be as non-intrusive as possible, we'll just make that call if the clock had non-default boundaries. Also add a few tests to make sure this case is covered. Fixes: c80ac50cbb37 ("clk: Always set the rate on clk_set_range_rate") Tested-by: Alexander Stein # imx8mp Tested-by: Marek Szyprowski # exynos4210, meson g12b Signed-off-by: Maxime Ripard --- drivers/clk/clk.c | 45 +++++++++++------ drivers/clk/clk_test.c | 108 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 139 insertions(+), 14 deletions(-) --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2330,19 +2330,15 @@ int clk_set_rate_exclusive(struct clk *c } EXPORT_SYMBOL_GPL(clk_set_rate_exclusive); -/** - * clk_set_rate_range - set a rate range for a clock source - * @clk: clock source - * @min: desired minimum clock rate in Hz, inclusive - * @max: desired maximum clock rate in Hz, inclusive - * - * Returns success (0) or negative errno. - */ -int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max) +static int clk_set_rate_range_nolock(struct clk *clk, + unsigned long min, + unsigned long max) { int ret = 0; unsigned long old_min, old_max, rate; + lockdep_assert_held(&prepare_lock); + if (!clk) return 0; @@ -2355,8 +2351,6 @@ int clk_set_rate_range(struct clk *clk, return -EINVAL; } - clk_prepare_lock(); - if (clk->exclusive_count) clk_core_rate_unprotect(clk->core); @@ -2400,6 +2394,28 @@ out: if (clk->exclusive_count) clk_core_rate_protect(clk->core); + return ret; +} + +/** + * clk_set_rate_range - set a rate range for a clock source + * @clk: clock source + * @min: desired minimum clock rate in Hz, inclusive + * @max: desired maximum clock rate in Hz, inclusive + * + * Return: 0 for success or negative errno on failure. + */ +int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max) +{ + int ret; + + if (!clk) + return 0; + + clk_prepare_lock(); + + ret = clk_set_rate_range_nolock(clk, min, max); + clk_prepare_unlock(); return ret; @@ -4359,9 +4375,10 @@ void __clk_put(struct clk *clk) } hlist_del(&clk->clks_node); - if (clk->min_rate > clk->core->req_rate || - clk->max_rate < clk->core->req_rate) - clk_core_set_rate_nolock(clk->core, clk->core->req_rate); + + /* If we had any boundaries on that clock, let's drop them. */ + if (clk->min_rate > 0 || clk->max_rate < ULONG_MAX) + clk_set_rate_range_nolock(clk, 0, ULONG_MAX); owner = clk->core->owner; kref_put(&clk->core->ref, __clk_release); --- a/drivers/clk/clk_test.c +++ b/drivers/clk/clk_test.c @@ -760,9 +760,65 @@ static void clk_range_test_multiple_set_ clk_put(user1); } +/* + * Test that if we have several subsequent calls to + * clk_set_rate_range(), across multiple users, the core will reevaluate + * whether a new rate is needed, including when a user drop its clock. + * + * With clk_dummy_maximize_rate_ops, this means that the rate will + * trail along the maximum as it evolves. + */ +static void clk_range_test_multiple_set_range_rate_put_maximized(struct kunit *test) +{ + struct clk_dummy_context *ctx = test->priv; + struct clk_hw *hw = &ctx->hw; + struct clk *clk = hw->clk; + struct clk *user1, *user2; + unsigned long rate; + + user1 = clk_hw_get_clk(hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user1); + + user2 = clk_hw_get_clk(hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user2); + + KUNIT_ASSERT_EQ(test, + clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000), + 0); + + KUNIT_ASSERT_EQ(test, + clk_set_rate_range(user1, + 0, + DUMMY_CLOCK_RATE_2), + 0); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2); + + KUNIT_ASSERT_EQ(test, + clk_set_rate_range(user2, + 0, + DUMMY_CLOCK_RATE_1), + 0); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1); + + clk_put(user2); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2); + + clk_put(user1); +} + static struct kunit_case clk_range_maximize_test_cases[] = { KUNIT_CASE(clk_range_test_set_range_rate_maximized), KUNIT_CASE(clk_range_test_multiple_set_range_rate_maximized), + KUNIT_CASE(clk_range_test_multiple_set_range_rate_put_maximized), {} }; @@ -877,9 +933,61 @@ static void clk_range_test_multiple_set_ clk_put(user1); } +/* + * Test that if we have several subsequent calls to + * clk_set_rate_range(), across multiple users, the core will reevaluate + * whether a new rate is needed, including when a user drop its clock. + * + * With clk_dummy_minimize_rate_ops, this means that the rate will + * trail along the minimum as it evolves. + */ +static void clk_range_test_multiple_set_range_rate_put_minimized(struct kunit *test) +{ + struct clk_dummy_context *ctx = test->priv; + struct clk_hw *hw = &ctx->hw; + struct clk *clk = hw->clk; + struct clk *user1, *user2; + unsigned long rate; + + user1 = clk_hw_get_clk(hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user1); + + user2 = clk_hw_get_clk(hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, user2); + + KUNIT_ASSERT_EQ(test, + clk_set_rate_range(user1, + DUMMY_CLOCK_RATE_1, + ULONG_MAX), + 0); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1); + + KUNIT_ASSERT_EQ(test, + clk_set_rate_range(user2, + DUMMY_CLOCK_RATE_2, + ULONG_MAX), + 0); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2); + + clk_put(user2); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1); + + clk_put(user1); +} + static struct kunit_case clk_range_minimize_test_cases[] = { KUNIT_CASE(clk_range_test_set_range_rate_minimized), KUNIT_CASE(clk_range_test_multiple_set_range_rate_minimized), + KUNIT_CASE(clk_range_test_multiple_set_range_rate_put_minimized), {} };