[PATCH 11/22] clk: Skip set_rate_range if our clock is orphan

[PATCH 11/22] clk: Skip set_rate_range if our clock is orphan

[Maxime Ripard]

clk_set_rate_range will now force a clk_set_rate() call to
core->req_rate. However, if our clock is orphan, req_rate will be 0 and
we will thus end up calling a set_rate to 0 on potentially all that
clock subtree.

This can be fairly invasive and result in poor decisions. In such a
case, let's just store the new range but bail out and skip the set_rate.

When that clock is no longer orphan though, we should be enforcing the
new range but we don't. Let's add a skipped test to make sure we don't
forget about that corner case.

Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/clk/clk.c      |  6 +++++
 drivers/clk/clk_test.c | 59 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 5b6ec11fcfcd..80fbec87309e 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2389,6 +2389,12 @@ static int clk_set_rate_range_nolock(struct clk *clk,
 	if (clk->core->flags & CLK_GET_RATE_NOCACHE)
 		rate = clk_core_get_rate_recalc(clk->core);
 
+	if (clk->core->orphan && !rate) {
+		pr_warn("%s: clk %s: Clock is orphan and doesn't have a rate!\n",
+			__func__, clk->core->name);
+		goto out;
+	}
+
 	/*
 	 * Since the boundaries have been changed, let's give the
 	 * opportunity to the provider to adjust the clock rate based on
diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index fa6e32c460ac..0fffc70f9e2c 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -735,6 +735,26 @@ clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_untouched(s
 	clk_put(parent);
 }
 
+/*
+ * Test that, for a mux whose current parent hasn't been registered yet,
+ * calling clk_set_rate_range() will succeed but won't affect its rate.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_range_get_rate(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk;
+	unsigned long rate;
+	int ret;
+
+	ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_EXPECT_EQ(test, rate, 0);
+}
+
 /*
  * Test that, for a mux whose current parent hasn't been registered yet,
  * calling clk_set_rate_range() will succeed, and will be taken into
@@ -758,6 +778,43 @@ clk_test_orphan_transparent_multiple_parent_mux_set_range_round_rate(struct kuni
 	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
 }
 
+/*
+ * Test that, for a mux that started orphan, was assigned and rate and
+ * then got switched to a valid parent, its rate is eventually within
+ * range.
+ *
+ * FIXME: Even though we update the rate as part of clk_set_parent(), we
+ * don't evaluate whether that new rate is within range and needs to be
+ * adjusted.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = hw->clk, *parent;
+	unsigned long rate;
+	int ret;
+
+	kunit_skip(test, "This needs to be fixed in the core.");
+
+	parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+
+	ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = clk_set_parent(clk, parent);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
+	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
+
+	clk_put(parent);
+}
+
 static struct kunit_case clk_orphan_transparent_multiple_parent_mux_test_cases[] = {
 	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_get_parent),
 	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent),
@@ -766,7 +823,9 @@ static struct kunit_case clk_orphan_transparent_multiple_parent_mux_test_cases[]
 	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_put),
 	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_modified),
 	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_untouched),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_get_rate),
 	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_round_rate),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate),
 	{}
 };
 
-- 
2.35.1

Re: [PATCH 11/22] clk: Skip set_rate_range if our clock is orphan

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 5086 bytes --]

CC: kbuild-all(a)lists.01.org
BCC: lkp(a)intel.com
In-Reply-To: <20220408091037.2041955-12-maxime@cerno.tech>
References: <20220408091037.2041955-12-maxime@cerno.tech>
TO: Maxime Ripard <maxime@cerno.tech>
TO: Mike Turquette <mturquette@baylibre.com>
TO: Stephen Boyd <sboyd@kernel.org>
TO: linux-clk(a)vger.kernel.org
CC: Naresh Kamboju <naresh.kamboju@linaro.org>
CC: Alexander Stein <alexander.stein@ew.tq-group.com>
CC: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Tony Lindgren <tony@atomide.com>
CC: Jerome Brunet <jbrunet@baylibre.com>
CC: Yassine Oudjana <y.oudjana@protonmail.com>
CC: Neil Armstrong <narmstrong@baylibre.com>
CC: Maxime Ripard <maxime@cerno.tech>

Hi Maxime,

I love your patch! Perhaps something to improve:

[auto build test WARNING on clk/clk-next]
[also build test WARNING on linus/master v5.18-rc1 next-20220408]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Maxime-Ripard/clk-More-clock-rate-fixes-and-tests/20220408-171635
base:   https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
:::::: branch date: 16 hours ago
:::::: commit date: 16 hours ago
config: riscv-randconfig-m031-20220408 (https://download.01.org/0day-ci/archive/20220409/202204090942.TPcGLjZX-lkp(a)intel.com/config)
compiler: riscv64-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

New smatch warnings:
drivers/clk/clk_test.c:801 clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate() warn: ignoring unreachable code.

Old smatch warnings:
drivers/clk/clk_test.c:929 clk_test_single_parent_mux_set_range_disjoint_child_last() warn: ignoring unreachable code.
drivers/clk/clk_test.c:959 clk_test_single_parent_mux_set_range_disjoint_parent_last() warn: ignoring unreachable code.

vim +801 drivers/clk/clk_test.c

d61deb9e36bc91 Maxime Ripard 2022-04-08  780  
2f0b8e802c7321 Maxime Ripard 2022-04-08  781  /*
2f0b8e802c7321 Maxime Ripard 2022-04-08  782   * Test that, for a mux that started orphan, was assigned and rate and
2f0b8e802c7321 Maxime Ripard 2022-04-08  783   * then got switched to a valid parent, its rate is eventually within
2f0b8e802c7321 Maxime Ripard 2022-04-08  784   * range.
2f0b8e802c7321 Maxime Ripard 2022-04-08  785   *
2f0b8e802c7321 Maxime Ripard 2022-04-08  786   * FIXME: Even though we update the rate as part of clk_set_parent(), we
2f0b8e802c7321 Maxime Ripard 2022-04-08  787   * don't evaluate whether that new rate is within range and needs to be
2f0b8e802c7321 Maxime Ripard 2022-04-08  788   * adjusted.
2f0b8e802c7321 Maxime Ripard 2022-04-08  789   */
2f0b8e802c7321 Maxime Ripard 2022-04-08  790  static void
2f0b8e802c7321 Maxime Ripard 2022-04-08  791  clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate(struct kunit *test)
2f0b8e802c7321 Maxime Ripard 2022-04-08  792  {
2f0b8e802c7321 Maxime Ripard 2022-04-08  793  	struct clk_multiple_parent_ctx *ctx = test->priv;
2f0b8e802c7321 Maxime Ripard 2022-04-08  794  	struct clk_hw *hw = &ctx->hw;
2f0b8e802c7321 Maxime Ripard 2022-04-08  795  	struct clk *clk = hw->clk, *parent;
2f0b8e802c7321 Maxime Ripard 2022-04-08  796  	unsigned long rate;
2f0b8e802c7321 Maxime Ripard 2022-04-08  797  	int ret;
2f0b8e802c7321 Maxime Ripard 2022-04-08  798  
2f0b8e802c7321 Maxime Ripard 2022-04-08  799  	kunit_skip(test, "This needs to be fixed in the core.");
2f0b8e802c7321 Maxime Ripard 2022-04-08  800  
2f0b8e802c7321 Maxime Ripard 2022-04-08 @801  	parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
2f0b8e802c7321 Maxime Ripard 2022-04-08  802  	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
2f0b8e802c7321 Maxime Ripard 2022-04-08  803  
2f0b8e802c7321 Maxime Ripard 2022-04-08  804  	ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2);
2f0b8e802c7321 Maxime Ripard 2022-04-08  805  	KUNIT_ASSERT_EQ(test, ret, 0);
2f0b8e802c7321 Maxime Ripard 2022-04-08  806  
2f0b8e802c7321 Maxime Ripard 2022-04-08  807  	ret = clk_set_parent(clk, parent);
2f0b8e802c7321 Maxime Ripard 2022-04-08  808  	KUNIT_ASSERT_EQ(test, ret, 0);
2f0b8e802c7321 Maxime Ripard 2022-04-08  809  
2f0b8e802c7321 Maxime Ripard 2022-04-08  810  	rate = clk_get_rate(clk);
2f0b8e802c7321 Maxime Ripard 2022-04-08  811  	KUNIT_ASSERT_GT(test, rate, 0);
2f0b8e802c7321 Maxime Ripard 2022-04-08  812  	KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
2f0b8e802c7321 Maxime Ripard 2022-04-08  813  	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
2f0b8e802c7321 Maxime Ripard 2022-04-08  814  
2f0b8e802c7321 Maxime Ripard 2022-04-08  815  	clk_put(parent);
2f0b8e802c7321 Maxime Ripard 2022-04-08  816  }
2f0b8e802c7321 Maxime Ripard 2022-04-08  817  

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