* [PATCH 1/2] clk: Update req_rate on __clk_recalc_rates()
2022-10-10 14:47 ` [PATCH 0/2] clk: More Range Fixes Maxime Ripard
@ 2022-10-10 14:47 ` Maxime Ripard
2022-10-11 3:43 ` Stephen Boyd
2022-10-10 14:47 ` [PATCH 2/2] clk: tests: Add tests for notifiers Maxime Ripard
2022-10-10 17:52 ` [PATCH 0/2] clk: More Range Fixes Marek Szyprowski
2 siblings, 1 reply; 6+ messages in thread
From: Maxime Ripard @ 2022-10-10 14:47 UTC (permalink / raw)
To: Stephen Boyd, Michael Turquette
Cc: linux-clk, Mark Brown, linux-kernel, Marek Szyprowski, Maxime Ripard
Commit cb1b1dd96241 ("clk: Set req_rate on reparenting") introduced a
new function, clk_core_update_orphan_child_rates(), that updates the
req_rate field on reparenting.
It turns out that that function will interfere with the clock notifying
done by __clk_recalc_rates(). This ends up reporting the new rate in
both the old_rate and new_rate fields of struct clk_notifier_data.
Since clk_core_update_orphan_child_rates() is basically
__clk_recalc_rates() without the notifiers, and with the req_rate field
update, we can drop clk_core_update_orphan_child_rates() entirely, and
make __clk_recalc_rates() update req_rate.
However, __clk_recalc_rates() is being called in several code paths:
when retrieving a rate (most likely through clk_get_rate()), when changing
parents (through clk_set_rate() or clk_hw_reparent()), or when updating
the orphan status (through clk_core_reparent_orphans_nolock(), called at
registration).
Updating req_rate on reparenting or initialisation makes sense, but we
shouldn't do it on clk_get_rate(). Thus an extra flag has been added to
update or not req_rate depending on the context.
Fixes: cb1b1dd96241 ("clk: Set req_rate on reparenting")
Link: https://lore.kernel.org/linux-clk/0acc7217-762c-7c0d-45a0-55c384824ce4@samsung.com/
Link: https://lore.kernel.org/linux-clk/Y0QNSx+ZgqKSvPOC@sirena.org.uk/
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Mark Brown <broonie@kernel.org>
Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
drivers/clk/clk.c | 39 +++++++++++----------------------------
1 file changed, 11 insertions(+), 28 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index dee5f39bfa90..c3c3f8c07258 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1759,6 +1759,7 @@ static unsigned long clk_recalc(struct clk_core *core,
/**
* __clk_recalc_rates
* @core: first clk in the subtree
+ * @update_req: Whether req_rate should be updated with the new rate
* @msg: notification type (see include/linux/clk.h)
*
* Walks the subtree of clks starting with clk and recalculates rates as it
@@ -1768,7 +1769,8 @@ static unsigned long clk_recalc(struct clk_core *core,
* clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
* if necessary.
*/
-static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
+static void __clk_recalc_rates(struct clk_core *core, bool update_req,
+ unsigned long msg)
{
unsigned long old_rate;
unsigned long parent_rate = 0;
@@ -1782,6 +1784,8 @@ static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
parent_rate = core->parent->rate;
core->rate = clk_recalc(core, parent_rate);
+ if (update_req)
+ core->req_rate = core->rate;
/*
* ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
@@ -1791,13 +1795,13 @@ static void __clk_recalc_rates(struct clk_core *core, unsigned long msg)
__clk_notify(core, msg, old_rate, core->rate);
hlist_for_each_entry(child, &core->children, child_node)
- __clk_recalc_rates(child, msg);
+ __clk_recalc_rates(child, update_req, msg);
}
static unsigned long clk_core_get_rate_recalc(struct clk_core *core)
{
if (core && (core->flags & CLK_GET_RATE_NOCACHE))
- __clk_recalc_rates(core, 0);
+ __clk_recalc_rates(core, false, 0);
return clk_core_get_rate_nolock(core);
}
@@ -1900,23 +1904,6 @@ static void clk_core_update_orphan_status(struct clk_core *core, bool is_orphan)
clk_core_update_orphan_status(child, is_orphan);
}
-/*
- * Update the orphan rate and req_rate of @core and all its children.
- */
-static void clk_core_update_orphan_child_rates(struct clk_core *core)
-{
- struct clk_core *child;
- unsigned long parent_rate = 0;
-
- if (core->parent)
- parent_rate = core->parent->rate;
-
- core->rate = core->req_rate = clk_recalc(core, parent_rate);
-
- hlist_for_each_entry(child, &core->children, child_node)
- clk_core_update_orphan_child_rates(child);
-}
-
static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
{
bool was_orphan = core->orphan;
@@ -1986,8 +1973,6 @@ static struct clk_core *__clk_set_parent_before(struct clk_core *core,
clk_reparent(core, parent);
clk_enable_unlock(flags);
- clk_core_update_orphan_child_rates(core);
-
return old_parent;
}
@@ -2033,7 +2018,6 @@ static int __clk_set_parent(struct clk_core *core, struct clk_core *parent,
clk_reparent(core, old_parent);
clk_enable_unlock(flags);
- clk_core_update_orphan_child_rates(core);
__clk_set_parent_after(core, old_parent, parent);
return ret;
@@ -2657,9 +2641,8 @@ static void clk_core_reparent(struct clk_core *core,
struct clk_core *new_parent)
{
clk_reparent(core, new_parent);
- clk_core_update_orphan_child_rates(core);
__clk_recalc_accuracies(core);
- __clk_recalc_rates(core, POST_RATE_CHANGE);
+ __clk_recalc_rates(core, true, POST_RATE_CHANGE);
}
void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
@@ -2743,9 +2726,9 @@ static int clk_core_set_parent_nolock(struct clk_core *core,
/* propagate rate an accuracy recalculation accordingly */
if (ret) {
- __clk_recalc_rates(core, ABORT_RATE_CHANGE);
+ __clk_recalc_rates(core, true, ABORT_RATE_CHANGE);
} else {
- __clk_recalc_rates(core, POST_RATE_CHANGE);
+ __clk_recalc_rates(core, true, POST_RATE_CHANGE);
__clk_recalc_accuracies(core);
}
@@ -3642,7 +3625,7 @@ static void clk_core_reparent_orphans_nolock(void)
__clk_set_parent_before(orphan, parent);
__clk_set_parent_after(orphan, parent, NULL);
__clk_recalc_accuracies(orphan);
- __clk_recalc_rates(orphan, 0);
+ __clk_recalc_rates(orphan, true, 0);
/*
* __clk_init_parent() will set the initial req_rate to
--
b4 0.11.0-dev-7da52
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 2/2] clk: tests: Add tests for notifiers
2022-10-10 14:47 ` [PATCH 0/2] clk: More Range Fixes Maxime Ripard
2022-10-10 14:47 ` [PATCH 1/2] clk: Update req_rate on __clk_recalc_rates() Maxime Ripard
@ 2022-10-10 14:47 ` Maxime Ripard
2022-10-11 3:43 ` Stephen Boyd
2022-10-10 17:52 ` [PATCH 0/2] clk: More Range Fixes Marek Szyprowski
2 siblings, 1 reply; 6+ messages in thread
From: Maxime Ripard @ 2022-10-10 14:47 UTC (permalink / raw)
To: Stephen Boyd, Michael Turquette
Cc: linux-clk, Mark Brown, linux-kernel, Marek Szyprowski, Maxime Ripard
We're recently encountered a regression due to the rates reported
through the clk_notifier_data being off when changing parents.
Let's add a test suite and a test to make sure that we do get notified
and with the proper rates.
Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
drivers/clk/clk_test.c | 156 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 156 insertions(+)
diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index 509256c5567a..f9a5c2964c65 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -2239,10 +2239,166 @@ static struct kunit_suite clk_leaf_mux_set_rate_parent_test_suite = {
.test_cases = clk_leaf_mux_set_rate_parent_test_cases,
};
+struct clk_mux_notifier_rate_change {
+ bool done;
+ unsigned long old_rate;
+ unsigned long new_rate;
+ wait_queue_head_t wq;
+};
+
+struct clk_mux_notifier_ctx {
+ struct clk_multiple_parent_ctx mux_ctx;
+ struct clk *clk;
+ struct notifier_block clk_nb;
+ struct clk_mux_notifier_rate_change pre_rate_change;
+ struct clk_mux_notifier_rate_change post_rate_change;
+};
+
+#define NOTIFIER_TIMEOUT_MS 100
+
+static int clk_mux_notifier_callback(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct clk_notifier_data *clk_data = data;
+ struct clk_mux_notifier_ctx *ctx = container_of(nb,
+ struct clk_mux_notifier_ctx,
+ clk_nb);
+
+ if (action & PRE_RATE_CHANGE) {
+ ctx->pre_rate_change.old_rate = clk_data->old_rate;
+ ctx->pre_rate_change.new_rate = clk_data->new_rate;
+ ctx->pre_rate_change.done = true;
+ wake_up_interruptible(&ctx->pre_rate_change.wq);
+ }
+
+ if (action & POST_RATE_CHANGE) {
+ ctx->post_rate_change.old_rate = clk_data->old_rate;
+ ctx->post_rate_change.new_rate = clk_data->new_rate;
+ ctx->post_rate_change.done = true;
+ wake_up_interruptible(&ctx->post_rate_change.wq);
+ }
+
+ return 0;
+}
+
+static int clk_mux_notifier_test_init(struct kunit *test)
+{
+ struct clk_mux_notifier_ctx *ctx;
+ const char *top_parents[2] = { "parent-0", "parent-1" };
+ int ret;
+
+ ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ test->priv = ctx;
+ ctx->clk_nb.notifier_call = clk_mux_notifier_callback;
+ init_waitqueue_head(&ctx->pre_rate_change.wq);
+ init_waitqueue_head(&ctx->post_rate_change.wq);
+
+ ctx->mux_ctx.parents_ctx[0].hw.init = CLK_HW_INIT_NO_PARENT("parent-0",
+ &clk_dummy_rate_ops,
+ 0);
+ ctx->mux_ctx.parents_ctx[0].rate = DUMMY_CLOCK_RATE_1;
+ ret = clk_hw_register(NULL, &ctx->mux_ctx.parents_ctx[0].hw);
+ if (ret)
+ return ret;
+
+ ctx->mux_ctx.parents_ctx[1].hw.init = CLK_HW_INIT_NO_PARENT("parent-1",
+ &clk_dummy_rate_ops,
+ 0);
+ ctx->mux_ctx.parents_ctx[1].rate = DUMMY_CLOCK_RATE_2;
+ ret = clk_hw_register(NULL, &ctx->mux_ctx.parents_ctx[1].hw);
+ if (ret)
+ return ret;
+
+ ctx->mux_ctx.current_parent = 0;
+ ctx->mux_ctx.hw.init = CLK_HW_INIT_PARENTS("test-mux", top_parents,
+ &clk_multiple_parents_mux_ops,
+ 0);
+ ret = clk_hw_register(NULL, &ctx->mux_ctx.hw);
+ if (ret)
+ return ret;
+
+ ctx->clk = clk_hw_get_clk(&ctx->mux_ctx.hw, NULL);
+ ret = clk_notifier_register(ctx->clk, &ctx->clk_nb);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void clk_mux_notifier_test_exit(struct kunit *test)
+{
+ struct clk_mux_notifier_ctx *ctx = test->priv;
+ struct clk *clk = ctx->clk;
+
+ clk_notifier_unregister(clk, &ctx->clk_nb);
+ clk_put(clk);
+
+ clk_hw_unregister(&ctx->mux_ctx.hw);
+ clk_hw_unregister(&ctx->mux_ctx.parents_ctx[0].hw);
+ clk_hw_unregister(&ctx->mux_ctx.parents_ctx[1].hw);
+}
+
+/*
+ * Test that if the we have a notifier registered on a mux, the core
+ * will notify us when we switch to another parent, and with the proper
+ * old and new rates.
+ */
+static void clk_mux_notifier_set_parent_test(struct kunit *test)
+{
+ struct clk_mux_notifier_ctx *ctx = test->priv;
+ struct clk_hw *hw = &ctx->mux_ctx.hw;
+ struct clk *clk = clk_hw_get_clk(hw, NULL);
+ struct clk *new_parent = clk_hw_get_clk(&ctx->mux_ctx.parents_ctx[1].hw, NULL);
+ int ret;
+
+ ret = clk_set_parent(clk, new_parent);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ ret = wait_event_interruptible_timeout(ctx->pre_rate_change.wq,
+ ctx->pre_rate_change.done,
+ msecs_to_jiffies(NOTIFIER_TIMEOUT_MS));
+ KUNIT_ASSERT_GT(test, ret, 0);
+
+ KUNIT_EXPECT_EQ(test, ctx->pre_rate_change.old_rate, DUMMY_CLOCK_RATE_1);
+ KUNIT_EXPECT_EQ(test, ctx->pre_rate_change.new_rate, DUMMY_CLOCK_RATE_2);
+
+ ret = wait_event_interruptible_timeout(ctx->post_rate_change.wq,
+ ctx->post_rate_change.done,
+ msecs_to_jiffies(NOTIFIER_TIMEOUT_MS));
+ KUNIT_ASSERT_GT(test, ret, 0);
+
+ KUNIT_EXPECT_EQ(test, ctx->post_rate_change.old_rate, DUMMY_CLOCK_RATE_1);
+ KUNIT_EXPECT_EQ(test, ctx->post_rate_change.new_rate, DUMMY_CLOCK_RATE_2);
+
+ clk_put(new_parent);
+ clk_put(clk);
+}
+
+static struct kunit_case clk_mux_notifier_test_cases[] = {
+ KUNIT_CASE(clk_mux_notifier_set_parent_test),
+ {}
+};
+
+/*
+ * Test suite for a mux with multiple parents, and a notifier registered
+ * on the mux.
+ *
+ * These tests exercise the behaviour of notifiers.
+ */
+static struct kunit_suite clk_mux_notifier_test_suite = {
+ .name = "clk-mux-notifier",
+ .init = clk_mux_notifier_test_init,
+ .exit = clk_mux_notifier_test_exit,
+ .test_cases = clk_mux_notifier_test_cases,
+};
+
kunit_test_suites(
&clk_leaf_mux_set_rate_parent_test_suite,
&clk_test_suite,
&clk_multiple_parents_mux_test_suite,
+ &clk_mux_notifier_test_suite,
&clk_orphan_transparent_multiple_parent_mux_test_suite,
&clk_orphan_transparent_single_parent_test_suite,
&clk_orphan_two_level_root_last_test_suite,
--
b4 0.11.0-dev-7da52
^ permalink raw reply [flat|nested] 6+ messages in thread