From: Stephen Boyd <sboyd@xxxxxxxxxx>
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 <abelvesa@xxxxxxxxxx>
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx>
Cc: "Andreas Färber" <afaerber@xxxxxxx>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
Cc: Chen-Yu Tsai <wens@xxxxxxxx>
Cc: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Cc: Chunyan Zhang <zhang.lyra@xxxxxxxxx>
Cc: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxxx>
Cc: David Lechner <david@xxxxxxxxxxxxxx>
Cc: Dinh Nguyen <dinguyen@xxxxxxxxxx>
Cc: Fabio Estevam <festevam@xxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: Jaroslav Kysela <perex@xxxxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
Cc: Jonathan Hunter <jonathanh@xxxxxxxxxx>
Cc: Kishon Vijay Abraham I <kishon@xxxxxxxxxx>
Cc: Liam Girdwood <lgirdwood@xxxxxxxxx>
Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
Cc: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
Cc: Manivannan Sadhasivam <mani@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Cc: Mikko Perttunen <mperttunen@xxxxxxxxxx>
Cc: Miles Chen <miles.chen@xxxxxxxxxxxx>
Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
Cc: Orson Zhai <orsonzhai@xxxxxxxxx>
Cc: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
Cc: Peng Fan <peng.fan@xxxxxxx>
Cc: Peter De Schrijver <pdeschrijver@xxxxxxxxxx>
Cc: Prashant Gaikwad <pgaikwad@xxxxxxxxxx>
Cc: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Cc: Samuel Holland <samuel@xxxxxxxxxxxx>
Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: Sekhar Nori <nsekhar@xxxxxx>
Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: Takashi Iwai <tiwai@xxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Cc: Vinod Koul <vkoul@xxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-actions@xxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-mips@xxxxxxxxxxxxxxx
Cc: linux-phy@xxxxxxxxxxxxxxxxxxx
Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
Cc: linux-rtc@xxxxxxxxxxxxxxx
Cc: linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-sunxi@xxxxxxxxxxxxxxx
Cc: linux-tegra@xxxxxxxxxxxxxxx
Cc: NXP Linux Team <linux-imx@xxxxxxx>
Cc: patches@xxxxxxxxxxxxxxxxxxxxx
Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
---
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
