From 655e66b0add0aba16e84587dbb939f8ddce612b0 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Fri, 1 Apr 2022 15:27:09 +0200 Subject: [PATCH] clk: Skip set_rate_range if our clock is orphan clk_set_rate_range will now force a clk_set_rate() call to core->req_rate. However, if our clock is orphan, req_rate will be 0 and we will thus end up calling a set_rate to 0 on potentially all that clock subtree. This can be fairly invasive and result in poor decisions. In such a case, let's just store the new range but bail out and skip the set_rate. When that clock is no longer orphan though, we should be enforcing the new range but we don't. Let's add a skipped test to make sure we don't forget about that corner case. 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 | 59 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+) --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2491,6 +2491,12 @@ static int clk_set_rate_range_nolock(str if (clk->core->flags & CLK_GET_RATE_NOCACHE) rate = clk_core_get_rate_recalc(clk->core); + if (clk->core->orphan && !rate) { + pr_warn("%s: clk %s: Clock is orphan and doesn't have a rate!\n", + __func__, clk->core->name); + goto out; + } + /* * Since the boundaries have been changed, let's give the * opportunity to the provider to adjust the clock rate based on --- a/drivers/clk/clk_test.c +++ b/drivers/clk/clk_test.c @@ -737,6 +737,26 @@ clk_test_orphan_transparent_multiple_par /* * Test that, for a mux whose current parent hasn't been registered yet, + * calling clk_set_rate_range() will succeed but won't affect its rate. + */ +static void +clk_test_orphan_transparent_multiple_parent_mux_set_range_get_rate(struct kunit *test) +{ + struct clk_multiple_parent_ctx *ctx = test->priv; + struct clk_hw *hw = &ctx->hw; + struct clk *clk = hw->clk; + unsigned long rate; + int ret; + + ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2); + KUNIT_ASSERT_EQ(test, ret, 0); + + rate = clk_get_rate(clk); + KUNIT_EXPECT_EQ(test, rate, 0); +} + +/* + * Test that, for a mux whose current parent hasn't been registered yet, * calling clk_set_rate_range() will succeed, and will be taken into * account when rounding a rate. */ @@ -758,6 +778,43 @@ clk_test_orphan_transparent_multiple_par KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2); } +/* + * Test that, for a mux that started orphan, was assigned and rate and + * then got switched to a valid parent, its rate is eventually within + * range. + * + * FIXME: Even though we update the rate as part of clk_set_parent(), we + * don't evaluate whether that new rate is within range and needs to be + * adjusted. + */ +static void +clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate(struct kunit *test) +{ + struct clk_multiple_parent_ctx *ctx = test->priv; + struct clk_hw *hw = &ctx->hw; + struct clk *clk = hw->clk, *parent; + unsigned long rate; + int ret; + + kunit_skip(test, "This needs to be fixed in the core."); + + parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent); + + ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2); + KUNIT_ASSERT_EQ(test, ret, 0); + + ret = clk_set_parent(clk, parent); + KUNIT_ASSERT_EQ(test, ret, 0); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1); + KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2); + + clk_put(parent); +} + static struct kunit_case clk_orphan_transparent_multiple_parent_mux_test_cases[] = { KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_get_parent), KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent), @@ -766,7 +823,9 @@ static struct kunit_case clk_orphan_tran KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_put), KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_modified), KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_untouched), + KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_get_rate), KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_round_rate), + KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate), {} };