From: Stephen Boyd <sb...@kernel.org>
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 <abelv...@kernel.org>
Cc: Alessandro Zummo <a.zu...@towertech.it>
Cc: Alexandre Belloni <alexandre.bell...@bootlin.com>
Cc: Alexandre Torgue <alexandre.tor...@foss.st.com>
Cc: "Andreas Färber" <afaer...@suse.de>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delre...@collabora.com>
Cc: Baolin Wang <baolin.w...@linux.alibaba.com>
Cc: Charles Keepax <ckee...@opensource.cirrus.com>
Cc: Chen-Yu Tsai <w...@csie.org>
Cc: Chen-Yu Tsai <we...@chromium.org>
Cc: Chunyan Zhang <zhang.l...@gmail.com>
Cc: Claudiu Beznea <claudiu.bez...@microchip.com>
Cc: Daniel Vetter <dan...@ffwll.ch>
Cc: David Airlie <airl...@gmail.com>
Cc: David Lechner <da...@lechnology.com>
Cc: Dinh Nguyen <dingu...@kernel.org>
Cc: Fabio Estevam <feste...@gmail.com>
Cc: Geert Uytterhoeven <geert+rene...@glider.be>
Cc: Jaroslav Kysela <pe...@perex.cz>
Cc: Jernej Skrabec <jernej.skra...@gmail.com>
Cc: Jonathan Hunter <jonath...@nvidia.com>
Cc: Kishon Vijay Abraham I <kis...@kernel.org>
Cc: Liam Girdwood <lgirdw...@gmail.com>
Cc: Linus Walleij <linus.wall...@linaro.org>
Cc: Luca Ceresoli <luca.ceres...@bootlin.com>
Cc: Manivannan Sadhasivam <m...@kernel.org>
Cc: Mark Brown <broo...@kernel.org>
Cc: Markus Schneider-Pargmann <m...@baylibre.com>
Cc: Max Filippov <jcmvb...@gmail.com>
Cc: Maxime Coquelin <mcoquelin.st...@gmail.com>
Cc: Mikko Perttunen <mperttu...@nvidia.com>
Cc: Miles Chen <miles.c...@mediatek.com>
Cc: Nicolas Ferre <nicolas.fe...@microchip.com>
Cc: Orson Zhai <orsonz...@gmail.com>
Cc: Paul Cercueil <p...@crapouillou.net>
Cc: Peng Fan <peng....@nxp.com>
Cc: Peter De Schrijver <pdeschrij...@nvidia.com>
Cc: Prashant Gaikwad <pgaik...@nvidia.com>
Cc: Richard Fitzgerald <r...@opensource.cirrus.com>
Cc: Samuel Holland <sam...@sholland.org>
Cc: Sascha Hauer <s.ha...@pengutronix.de>
Cc: Sekhar Nori <nsek...@ti.com>
Cc: Shawn Guo <shawn...@kernel.org>
Cc: Takashi Iwai <ti...@suse.com>
Cc: Thierry Reding <thierry.red...@gmail.com>
Cc: Ulf Hansson <ulf.hans...@linaro.org>
Cc: Vinod Koul <vk...@kernel.org>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-acti...@lists.infradead.org
Cc: linux-arm-ker...@lists.infradead.org
Cc: linux-m...@vger.kernel.org
Cc: linux-...@lists.infradead.org
Cc: linux-renesas-...@vger.kernel.org
Cc: linux-...@vger.kernel.org
Cc: linux-st...@st-md-mailman.stormreply.com
Cc: linux-su...@lists.linux.dev
Cc: linux-te...@vger.kernel.org
Cc: NXP Linux Team <linux-...@nxp.com>
Cc: patc...@opensource.cirrus.com
Cc: Pengutronix Kernel Team <ker...@pengutronix.de>
Signed-off-by: Stephen Boyd <sb...@kernel.org>
Signed-off-by: Maxime Ripard <max...@cerno.tech>
---
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
