target/linux/bcm27xx/patches-5.15/950-0832-clk-Always-clamp-the-rounded-rate.patch

   1 From 9db7cf9f810ff5092e664078165b2e066e546f6a Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Wed, 5 May 2021 15:35:34 +0200
   4 Subject: [PATCH] clk: Always clamp the rounded rate
   5
   6 The current core while setting the min and max rate properly in the
   7 clk_request structure will not make sure that the requested rate is
   8 within these boundaries, leaving it to each and every driver to make
   9 sure it is.
  10
  11 It's not clear if this was on purpose or not, but this introduces some
  12 inconsistencies within the API.
  13
  14 For example, a user setting a range and then calling clk_round_rate()
  15 with a value outside of that range will get the same value back
  16 (ignoring any driver adjustements), effectively ignoring the range that
  17 was just set.
  18
  19 Another one, arguably worse, is that it also makes clk_round_rate() and
  20 clk_set_rate() behave differently if there's a range and the rate being
  21 used for both is outside that range. As we have seen, the rate will be
  22 returned unchanged by clk_round_rate(), but clk_set_rate() will error
  23 out returning -EINVAL.
  24
  25 Let's make sure the framework will always clamp the rate to the current
  26 range found on the clock, which will fix both these inconsistencies.
  27
  28 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  29 ---
  30  drivers/clk/clk_test.c | 50 +++++++++++++++++++++++++++---------------
  31  1 file changed, 32 insertions(+), 18 deletions(-)
  32
  33 --- a/drivers/clk/clk_test.c
  34 +++ b/drivers/clk/clk_test.c
  35 @@ -310,8 +310,7 @@ static void clk_range_test_multiple_disj
  36
  37  /*
  38   * Test that if our clock has some boundaries and we try to round a rate
  39 - * lower than the minimum, the returned rate won't be affected by the
  40 - * boundaries.
  41 + * lower than the minimum, the returned rate will be within range.
  42   */
  43  static void clk_range_test_set_range_round_rate_lower(struct kunit *test)
  44  {
  45 @@ -328,18 +327,20 @@ static void clk_range_test_set_range_rou
  46
  47         rate = clk_round_rate(clk, DUMMY_CLOCK_RATE_1 - 1000);
  48         KUNIT_ASSERT_GT(test, rate, 0);
  49 -       KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1 - 1000);
  50 +       KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
  51 +       KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
  52  }
  53
  54  /*
  55   * Test that if our clock has some boundaries and we try to set a rate
  56 - * lower than the minimum, we'll get an error.
  57 + * higher than the maximum, the new rate will be within range.
  58   */
  59  static void clk_range_test_set_range_set_rate_lower(struct kunit *test)
  60  {
  61         struct clk_dummy_context *ctx = test->priv;
  62         struct clk_hw *hw = &ctx->hw;
  63         struct clk *clk = hw->clk;
  64 +       unsigned long rate;
  65
  66         KUNIT_ASSERT_EQ(test,
  67                         clk_set_rate_range(clk,
  68 @@ -347,15 +348,21 @@ static void clk_range_test_set_range_set
  69                                            DUMMY_CLOCK_RATE_2),
  70                         0);
  71
  72 -       KUNIT_ASSERT_LT(test,
  73 +       KUNIT_ASSERT_EQ(test,
  74                         clk_set_rate(clk, DUMMY_CLOCK_RATE_1 - 1000),
  75                         0);
  76 +
  77 +       rate = clk_get_rate(clk);
  78 +       KUNIT_ASSERT_GT(test, rate, 0);
  79 +       KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
  80 +       KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
  81  }
  82
  83  /*
  84   * Test that if our clock has some boundaries and we try to round and
  85 - * set a rate lower than the minimum, the values won't be consistent
  86 - * between clk_round_rate() and clk_set_rate().
  87 + * set a rate lower than the minimum, the rate returned by
  88 + * clk_round_rate() will be consistent with the new rate set by
  89 + * clk_set_rate().
  90   */
  91  static void clk_range_test_set_range_set_round_rate_consistent_lower(struct kunit *test)
  92  {
  93 @@ -373,17 +380,16 @@ static void clk_range_test_set_range_set
  94         rounded = clk_round_rate(clk, DUMMY_CLOCK_RATE_1 - 1000);
  95         KUNIT_ASSERT_GT(test, rounded, 0);
  96
  97 -       KUNIT_EXPECT_LT(test,
  98 +       KUNIT_ASSERT_EQ(test,
  99                         clk_set_rate(clk, DUMMY_CLOCK_RATE_1 - 1000),
 100                         0);
 101
 102 -       KUNIT_EXPECT_NE(test, rounded, clk_get_rate(clk));
 103 +       KUNIT_EXPECT_EQ(test, rounded, clk_get_rate(clk));
 104  }
 105
 106  /*
 107   * Test that if our clock has some boundaries and we try to round a rate
 108 - * higher than the maximum, the returned rate won't be affected by the
 109 - * boundaries.
 110 + * higher than the maximum, the returned rate will be within range.
 111   */
 112  static void clk_range_test_set_range_round_rate_higher(struct kunit *test)
 113  {
 114 @@ -400,18 +406,20 @@ static void clk_range_test_set_range_rou
 115
 116         rate = clk_round_rate(clk, DUMMY_CLOCK_RATE_2 + 1000);
 117         KUNIT_ASSERT_GT(test, rate, 0);
 118 -       KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_2 + 1000);
 119 +       KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
 120 +       KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
 121  }
 122
 123  /*
 124   * Test that if our clock has some boundaries and we try to set a rate
 125 - * lower than the maximum, we'll get an error.
 126 + * higher than the maximum, the new rate will be within range.
 127   */
 128  static void clk_range_test_set_range_set_rate_higher(struct kunit *test)
 129  {
 130         struct clk_dummy_context *ctx = test->priv;
 131         struct clk_hw *hw = &ctx->hw;
 132         struct clk *clk = hw->clk;
 133 +       unsigned long rate;
 134
 135         KUNIT_ASSERT_EQ(test,
 136                         clk_set_rate_range(clk,
 137 @@ -419,15 +427,21 @@ static void clk_range_test_set_range_set
 138                                            DUMMY_CLOCK_RATE_2),
 139                         0);
 140
 141 -       KUNIT_ASSERT_LT(test,
 142 +       KUNIT_ASSERT_EQ(test,
 143                         clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
 144                         0);
 145 +
 146 +       rate = clk_get_rate(clk);
 147 +       KUNIT_ASSERT_GT(test, rate, 0);
 148 +       KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
 149 +       KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
 150  }
 151
 152  /*
 153   * Test that if our clock has some boundaries and we try to round and
 154 - * set a rate higher than the maximum, the values won't be consistent
 155 - * between clk_round_rate() and clk_set_rate().
 156 + * set a rate higher than the maximum, the rate returned by
 157 + * clk_round_rate() will be consistent with the new rate set by
 158 + * clk_set_rate().
 159   */
 160  static void clk_range_test_set_range_set_round_rate_consistent_higher(struct kunit *test)
 161  {
 162 @@ -445,11 +459,11 @@ static void clk_range_test_set_range_set
 163         rounded = clk_round_rate(clk, DUMMY_CLOCK_RATE_2 + 1000);
 164         KUNIT_ASSERT_GT(test, rounded, 0);
 165
 166 -       KUNIT_EXPECT_LT(test,
 167 +       KUNIT_ASSERT_EQ(test,
 168                         clk_set_rate(clk, DUMMY_CLOCK_RATE_2 + 1000),
 169                         0);
 170
 171 -       KUNIT_EXPECT_NE(test, rounded, clk_get_rate(clk));
 172 +       KUNIT_EXPECT_EQ(test, rounded, clk_get_rate(clk));
 173  }
 174
 175  /*