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clk: Drop the rate range on clk_put()

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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: c80ac50cbb ("clk: Always set the rate on clk_set_range_rate")
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/20220816112530.1837489-3-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 13:25:07 +02:00 committed by Stephen Boyd
parent aac00c7fa1
commit d773882232
2 changed files with 141 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
drivers/clk/clk.c
View File

@ -2325,19 +2325,15 @@ int clk_set_rate_exclusive(struct clk *clk, unsigned long rate)
}
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;
@ -2350,8 +2346,6 @@ int clk_set_rate_range(struct clk *clk, unsigned long min, unsigned long max)
return -EINVAL;
}
clk_prepare_lock();
if (clk->exclusive_count)
clk_core_rate_unprotect(clk->core);
@ -2395,6 +2389,28 @@ 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;
@ -4348,9 +4364,10 @@ 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);

110
drivers/clk/clk_test.c
View File

@ -793,9 +793,66 @@ static void clk_range_test_multiple_set_range_rate_maximized(struct kunit *test)
clk_put(clk);
}
/*
* 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 = clk_hw_get_clk(hw, NULL);
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);
clk_put(clk);
}
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),
{}
};
@ -913,9 +970,62 @@ static void clk_range_test_multiple_set_range_rate_minimized(struct kunit *test)
clk_put(clk);
}
/*
* 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 = clk_hw_get_clk(hw, NULL);
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);
clk_put(clk);
}
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),
{}
};