linux-kernel - [PATCH 2/2] clk: Introduce kunit wrapper around __clk_determine

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Message-Id: <20230721-clk-fix-kunit-lockdep-v1-2-32cdba4c8fc1@kernel.org>
Date:   Fri, 21 Jul 2023 09:09:33 +0200
From:   Maxime Ripard <mripard@...nel.org>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Maxime Ripard <mripard@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        kernel test robot <yujie.liu@...el.com>
Subject: [PATCH 2/2] clk: Introduce kunit wrapper around
 __clk_determine_rate

Some kunit tests are meant to test the behaviour of providers but don't
run those functions with the clk prepare_lock held which results in
lockdep warning.

__clk_determine_rate is one of the functions being executed from a test
which should have the lock held. Let's introduce a wrapper around it
meant to be used only by kunit tests.

Reported-by: Guenter Roeck <linux@...ck-us.net>
Link: https://lore.kernel.org/linux-clk/2b594e50-2bbf-4a2d-88e6-49fc39f3957a@roeck-us.net/
Reported-by: kernel test robot <yujie.liu@...el.com>
Link: https://lore.kernel.org/oe-lkp/202301310919.b9d56ee3-yujie.liu@intel.com
Fixes: 262ca38f4b6e ("clk: Stop forwarding clk_rate_requests to the parent")
Signed-off-by: Maxime Ripard <mripard@...nel.org>
---
 drivers/clk/clk.c            | 25 +++++++++++++++++++++++++
 drivers/clk/clk_test.c       |  2 +-
 include/linux/clk-provider.h | 10 ++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8ee9bd02af76..8fdbfec6bd85 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1669,6 +1669,31 @@ int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
 }
 EXPORT_SYMBOL_GPL(__clk_determine_rate);
 
+#if IS_ENABLED(CONFIG_KUNIT)
+/**
+ * __clk_kunit_determine_rate - get the closest rate actually supported by a clock
+ * @hw: determine the rate of this clock
+ * @req: target rate request
+ *
+ * Useful for clk_ops such as .set_rate and .determine_rate. Only usable
+ * in a kunit test context. Use __clk_determine_rate() otherwise.
+ */
+int __clk_kunit_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+	int ret;
+
+	if (!kunit_get_current_test())
+		return -EINVAL;
+
+	clk_prepare_lock();
+	ret = __clk_determine_rate(hw, req);
+	clk_prepare_unlock();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__clk_kunit_determine_rate);
+#endif
+
 /**
  * clk_hw_round_rate() - round the given rate for a hw clk
  * @hw: the hw clk for which we are rounding a rate
diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index a64f7036baa3..b835e08892b4 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -2232,7 +2232,7 @@ static void clk_leaf_mux_set_rate_parent_determine_rate(struct kunit *test)
 
 	clk_kunit_init_rate_request(hw, &req, DUMMY_CLOCK_RATE_2);
 
-	ret = __clk_determine_rate(hw, &req);
+	ret = __clk_kunit_determine_rate(hw, &req);
 	KUNIT_ASSERT_EQ(test, ret, 0);
 
 	KUNIT_EXPECT_EQ(test, req.rate, DUMMY_CLOCK_RATE_2);
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index efdebfa3fce9..43049f2c1dd2 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1352,6 +1352,16 @@ void clk_hw_get_rate_range(struct clk_hw *hw, unsigned long *min_rate,
 void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate,
 			   unsigned long max_rate);
 
+#if IS_ENABLED(CONFIG_KUNIT)
+int __clk_kunit_determine_rate(struct clk_hw *hw, struct clk_rate_request *req);
+#else
+static inline int __clk_kunit_determine_rate(struct clk_hw *hw,
+					     struct clk_rate_request *req)
+{
+	return -ENOENT;
+}
+#endif
+
 static inline void __clk_hw_set_clk(struct clk_hw *dst, struct clk_hw *src)
 {
 	dst->clk = src->clk;

-- 
2.41.0