target/linux/bcm27xx/patches-5.15/950-0844-clk-Take-into-account-uncached-clocks-in-clk_set_rat.patch

   1 From 4ec4cfbf63a697a5b1c82b400d28afd0347d555a Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Fri, 8 Apr 2022 10:06:11 +0200
   4 Subject: [PATCH] clk: Take into account uncached clocks in
   5  clk_set_rate_range()
   6
   7 clk_set_rate_range() will use the last requested rate for the clock when
   8 it calls into the driver set_rate hook.
   9
  10 However, if CLK_GET_RATE_NOCACHE is set on that clock, the last
  11 requested rate might not be matching the current rate of the clock. In
  12 such a case, let's read out the rate from the hardware and use that in
  13 our set_rate instead.
  14
  15 Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
  16 Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
  17 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  18 ---
  19  drivers/clk/clk.c      |  6 +++++-
  20  drivers/clk/clk_test.c | 28 ++++++++++++++++++++++++++++
  21  2 files changed, 33 insertions(+), 1 deletion(-)
  22
  23 --- a/drivers/clk/clk.c
  24 +++ b/drivers/clk/clk.c
  25 @@ -2365,6 +2365,10 @@ static int clk_set_rate_range_nolock(str
  26                 goto out;
  27         }
  28
  29 +       rate = clk->core->req_rate;
  30 +       if (clk->core->flags & CLK_GET_RATE_NOCACHE)
  31 +               rate = clk_core_get_rate_recalc(clk->core);
  32 +
  33         /*
  34          * Since the boundaries have been changed, let's give the
  35          * opportunity to the provider to adjust the clock rate based on
  36 @@ -2382,7 +2386,7 @@ static int clk_set_rate_range_nolock(str
  37          * - the determine_rate() callback does not really check for
  38          *   this corner case when determining the rate
  39          */
  40 -       rate = clamp(clk->core->req_rate, min, max);
  41 +       rate = clamp(rate, min, max);
  42         ret = clk_core_set_rate_nolock(clk->core, rate);
  43         if (ret) {
  44                 /* rollback the changes */
  45 --- a/drivers/clk/clk_test.c
  46 +++ b/drivers/clk/clk_test.c
  47 @@ -362,9 +362,37 @@ static void clk_test_uncached_set_range(
  48         KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
  49  }
  50
  51 +/*
  52 + * Test that for an uncached clock, clk_set_rate_range() will work
  53 + * properly if the rate has changed in hardware.
  54 + *
  55 + * In this case, it means that if the rate wasn't initially in the range
  56 + * we're trying to set, but got changed at some point into the range
  57 + * without the kernel knowing about it, its rate shouldn't be affected.
  58 + */
  59 +static void clk_test_uncached_updated_rate_set_range(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 +       ctx->rate = DUMMY_CLOCK_RATE_1 + 1000;
  67 +       KUNIT_ASSERT_EQ(test,
  68 +                       clk_set_rate_range(clk,
  69 +                                          DUMMY_CLOCK_RATE_1,
  70 +                                          DUMMY_CLOCK_RATE_2),
  71 +                       0);
  72 +
  73 +       rate = clk_get_rate(clk);
  74 +       KUNIT_ASSERT_GT(test, rate, 0);
  75 +       KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_RATE_1 + 1000);
  76 +}
  77 +
  78  static struct kunit_case clk_uncached_test_cases[] = {
  79         KUNIT_CASE(clk_test_uncached_get_rate),
  80         KUNIT_CASE(clk_test_uncached_set_range),
  81 +       KUNIT_CASE(clk_test_uncached_updated_rate_set_range),
  82         {}
  83  };
  84