From: Stephen Boyd <[email protected]> Some clock drivers do not want to allow any reparenting on a given clock, but usually do so by not providing any determine_rate implementation.
Whenever we call clk_round_rate() or clk_set_rate(), this leads to clk_core_can_round() returning false and thus the rest of the function either forwarding the rate request to its current parent if CLK_SET_RATE_PARENT is set, or just returning the current clock rate. This behaviour happens implicitly, and as we move forward to making a determine_rate implementation required for muxes, we need some way to explicitly opt-in for that behaviour. Fortunately, this is exactly what the clk_core_determine_rate_no_reparent() function is doing, so we can simply make it available to drivers. Cc: Abel Vesa <[email protected]> Cc: Alessandro Zummo <[email protected]> Cc: Alexandre Belloni <[email protected]> Cc: Alexandre Torgue <[email protected]> Cc: "Andreas Färber" <[email protected]> Cc: AngeloGioacchino Del Regno <[email protected]> Cc: Baolin Wang <[email protected]> Cc: Charles Keepax <[email protected]> Cc: Chen-Yu Tsai <[email protected]> Cc: Chen-Yu Tsai <[email protected]> Cc: Chunyan Zhang <[email protected]> Cc: Claudiu Beznea <[email protected]> Cc: Daniel Vetter <[email protected]> Cc: David Airlie <[email protected]> Cc: David Lechner <[email protected]> Cc: Dinh Nguyen <[email protected]> Cc: Fabio Estevam <[email protected]> Cc: Geert Uytterhoeven <[email protected]> Cc: Jaroslav Kysela <[email protected]> Cc: Jernej Skrabec <[email protected]> Cc: Jonathan Hunter <[email protected]> Cc: Kishon Vijay Abraham I <[email protected]> Cc: Liam Girdwood <[email protected]> Cc: Linus Walleij <[email protected]> Cc: Luca Ceresoli <[email protected]> Cc: Manivannan Sadhasivam <[email protected]> Cc: Mark Brown <[email protected]> Cc: Markus Schneider-Pargmann <[email protected]> Cc: Max Filippov <[email protected]> Cc: Maxime Coquelin <[email protected]> Cc: Mikko Perttunen <[email protected]> Cc: Miles Chen <[email protected]> Cc: Nicolas Ferre <[email protected]> Cc: Orson Zhai <[email protected]> Cc: Paul Cercueil <[email protected]> Cc: Peng Fan <[email protected]> Cc: Peter De Schrijver <[email protected]> Cc: Prashant Gaikwad <[email protected]> Cc: Richard Fitzgerald <[email protected]> Cc: Samuel Holland <[email protected]> Cc: Sascha Hauer <[email protected]> Cc: Sekhar Nori <[email protected]> Cc: Shawn Guo <[email protected]> Cc: Takashi Iwai <[email protected]> Cc: Thierry Reding <[email protected]> Cc: Ulf Hansson <[email protected]> Cc: Vinod Koul <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: NXP Linux Team <[email protected]> Cc: [email protected] Cc: Pengutronix Kernel Team <[email protected]> Signed-off-by: Stephen Boyd <[email protected]> Signed-off-by: Maxime Ripard <[email protected]> --- drivers/clk/clk.c | 18 +++++ drivers/clk/clk_test.c | 152 +++++++++++++++++++++++++++++++++++++++++++ include/linux/clk-provider.h | 2 + 3 files changed, 172 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index f57f821a5e5a..5365595433c8 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -783,6 +783,24 @@ int __clk_mux_determine_rate_closest(struct clk_hw *hw, } EXPORT_SYMBOL_GPL(__clk_mux_determine_rate_closest); +/* + * clk_hw_determine_rate_no_reparent - clk_ops::determine_rate implementation for a clk that doesn't reparent + * @hw: mux type clk to determine rate on + * @req: rate request, also used to return preferred frequency + * + * Helper for finding best parent rate to provide a given frequency. + * This can be used directly as a determine_rate callback (e.g. for a + * mux), or from a more complex clock that may combine a mux with other + * operations. + * + * Returns: 0 on success, -EERROR value on error + */ +int clk_hw_determine_rate_no_reparent(struct clk_hw *hw, + struct clk_rate_request *req) +{ + return clk_core_determine_rate_no_reparent(hw, req); +} + /*** clk api ***/ static void clk_core_rate_unprotect(struct clk_core *core) diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c index 2cb51153750d..b3ed3b0e4c31 100644 --- a/drivers/clk/clk_test.c +++ b/drivers/clk/clk_test.c @@ -141,6 +141,12 @@ static const struct clk_ops clk_multiple_parents_mux_ops = { .determine_rate = __clk_mux_determine_rate_closest, }; +static const struct clk_ops clk_multiple_parents_no_reparent_mux_ops = { + .determine_rate = clk_hw_determine_rate_no_reparent, + .get_parent = clk_multiple_parents_mux_get_parent, + .set_parent = clk_multiple_parents_mux_set_parent, +}; + static int clk_test_init_with_ops(struct kunit *test, const struct clk_ops *ops) { struct clk_dummy_context *ctx; @@ -2395,10 +2401,156 @@ static struct kunit_suite clk_mux_notifier_test_suite = { .test_cases = clk_mux_notifier_test_cases, }; +static int +clk_mux_no_reparent_test_init(struct kunit *test) +{ + struct clk_multiple_parent_ctx *ctx; + const char *parents[2] = { "parent-0", "parent-1"}; + int ret; + + ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + test->priv = ctx; + + ctx->parents_ctx[0].hw.init = CLK_HW_INIT_NO_PARENT("parent-0", + &clk_dummy_rate_ops, + 0); + ctx->parents_ctx[0].rate = DUMMY_CLOCK_RATE_1; + ret = clk_hw_register(NULL, &ctx->parents_ctx[0].hw); + if (ret) + return ret; + + ctx->parents_ctx[1].hw.init = CLK_HW_INIT_NO_PARENT("parent-1", + &clk_dummy_rate_ops, + 0); + ctx->parents_ctx[1].rate = DUMMY_CLOCK_RATE_2; + ret = clk_hw_register(NULL, &ctx->parents_ctx[1].hw); + if (ret) + return ret; + + ctx->current_parent = 0; + ctx->hw.init = CLK_HW_INIT_PARENTS("test-mux", parents, + &clk_multiple_parents_no_reparent_mux_ops, + 0); + ret = clk_hw_register(NULL, &ctx->hw); + if (ret) + return ret; + + return 0; +} + +static void +clk_mux_no_reparent_test_exit(struct kunit *test) +{ + struct clk_multiple_parent_ctx *ctx = test->priv; + + clk_hw_unregister(&ctx->hw); + clk_hw_unregister(&ctx->parents_ctx[0].hw); + clk_hw_unregister(&ctx->parents_ctx[1].hw); +} + +/* + * Test that if the we have a mux that cannot change parent and we call + * clk_round_rate() on it with a rate that should cause it to change + * parent, it won't. + */ +static void clk_mux_no_reparent_round_rate(struct kunit *test) +{ + struct clk_multiple_parent_ctx *ctx = test->priv; + struct clk_hw *hw = &ctx->hw; + struct clk *clk = clk_hw_get_clk(hw, NULL); + struct clk *other_parent, *parent; + unsigned long other_parent_rate; + unsigned long parent_rate; + long rounded_rate; + + parent = clk_get_parent(clk); + KUNIT_ASSERT_PTR_NE(test, parent, NULL); + + parent_rate = clk_get_rate(parent); + KUNIT_ASSERT_GT(test, parent_rate, 0); + + other_parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, other_parent); + KUNIT_ASSERT_FALSE(test, clk_is_match(parent, other_parent)); + + other_parent_rate = clk_get_rate(other_parent); + KUNIT_ASSERT_GT(test, other_parent_rate, 0); + clk_put(other_parent); + + rounded_rate = clk_round_rate(clk, other_parent_rate); + KUNIT_ASSERT_GT(test, rounded_rate, 0); + KUNIT_EXPECT_EQ(test, rounded_rate, parent_rate); + + clk_put(clk); +} + +/* + * Test that if the we have a mux that cannot change parent and we call + * clk_set_rate() on it with a rate that should cause it to change + * parent, it won't. + */ +static void clk_mux_no_reparent_set_rate(struct kunit *test) +{ + struct clk_multiple_parent_ctx *ctx = test->priv; + struct clk_hw *hw = &ctx->hw; + struct clk *clk = clk_hw_get_clk(hw, NULL); + struct clk *other_parent, *parent; + unsigned long other_parent_rate; + unsigned long parent_rate; + unsigned long rate; + int ret; + + parent = clk_get_parent(clk); + KUNIT_ASSERT_PTR_NE(test, parent, NULL); + + parent_rate = clk_get_rate(parent); + KUNIT_ASSERT_GT(test, parent_rate, 0); + + other_parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, other_parent); + KUNIT_ASSERT_FALSE(test, clk_is_match(parent, other_parent)); + + other_parent_rate = clk_get_rate(other_parent); + KUNIT_ASSERT_GT(test, other_parent_rate, 0); + clk_put(other_parent); + + ret = clk_set_rate(clk, other_parent_rate); + KUNIT_ASSERT_EQ(test, ret, 0); + + rate = clk_get_rate(clk); + KUNIT_ASSERT_GT(test, rate, 0); + KUNIT_EXPECT_EQ(test, rate, parent_rate); + + clk_put(clk); +} + +static struct kunit_case clk_mux_no_reparent_test_cases[] = { + KUNIT_CASE(clk_mux_no_reparent_round_rate), + KUNIT_CASE(clk_mux_no_reparent_set_rate), + {} +}; + +/* + * Test suite for a clock mux that isn't allowed to change parent, using + * the clk_hw_determine_rate_no_reparent() helper. + * + * These tests exercise that helper, and the proper selection of + * rates and parents. + */ +static struct kunit_suite clk_mux_no_reparent_test_suite = { + .name = "clk-mux-no-reparent", + .init = clk_mux_no_reparent_test_init, + .exit = clk_mux_no_reparent_test_exit, + .test_cases = clk_mux_no_reparent_test_cases, +}; + kunit_test_suites( &clk_leaf_mux_set_rate_parent_test_suite, &clk_test_suite, &clk_multiple_parents_mux_test_suite, + &clk_mux_no_reparent_test_suite, &clk_mux_notifier_test_suite, &clk_orphan_transparent_multiple_parent_mux_test_suite, &clk_orphan_transparent_single_parent_test_suite, diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 28ff6f1a6ada..f8f220fb5dab 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -1333,6 +1333,8 @@ int __clk_mux_determine_rate_closest(struct clk_hw *hw, int clk_mux_determine_rate_flags(struct clk_hw *hw, struct clk_rate_request *req, unsigned long flags); +int clk_hw_determine_rate_no_reparent(struct clk_hw *hw, + struct clk_rate_request *req); void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent); void clk_hw_get_rate_range(struct clk_hw *hw, unsigned long *min_rate, unsigned long *max_rate); -- 2.40.0
