target/linux/bcm27xx/patches-5.4/950-0533-clk-bcm-rpi-Discover-the-firmware-clocks.patch

   1 From 54276fe20c0735dd18d298891b71b664ea54962d Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Mon, 10 Feb 2020 14:06:09 +0100
   4 Subject: [PATCH] clk: bcm: rpi: Discover the firmware clocks
   5
   6 The RaspberryPi4 firmware actually exposes more clocks than are currently
   7 handled by the driver and we will need to change some of them directly
   8 based on the pixel rate for the display related clocks, or the load for the
   9 GPU.
  10
  11 This rate change can have a number of side-effects, including adjusting the
  12 various PLL voltages or the PLL parents. The firmware will also update
  13 those clocks by itself for example if the SoC runs too hot.
  14
  15 In order to make Linux play as nice as possible with those constraints, it
  16 makes sense to rely on the firmware clocks as much as possible.
  17
  18 Fortunately,t he firmware has an interface to discover the clocks it
  19 exposes.
  20
  21 Let's use it to discover, register the clocks in the clocks framework and
  22 then expose them through the device tree for consumers to use them.
  23
  24 Cc: Michael Turquette <mturquette@baylibre.com>
  25 Cc: Stephen Boyd <sboyd@kernel.org>
  26 Cc: linux-clk@vger.kernel.org
  27 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  28 ---
  29  drivers/clk/bcm/clk-raspberrypi.c          | 104 ++++++++++++++++++---
  30  include/soc/bcm2835/raspberrypi-firmware.h |   5 +
  31  2 files changed, 97 insertions(+), 12 deletions(-)
  32
  33 --- a/drivers/clk/bcm/clk-raspberrypi.c
  34 +++ b/drivers/clk/bcm/clk-raspberrypi.c
  35 @@ -285,6 +285,95 @@ static struct clk_hw *raspberrypi_regist
  36         return &raspberrypi_clk_pllb_arm.hw;
  37  }
  38
  39 +static long raspberrypi_fw_dumb_round_rate(struct clk_hw *hw,
  40 +                                          unsigned long rate,
  41 +                                          unsigned long *parent_rate)
  42 +{
  43 +       /*
  44 +        * The firmware will do the rounding but that isn't part of
  45 +        * the interface with the firmware, so we just do our best
  46 +        * here.
  47 +        */
  48 +       return rate;
  49 +}
  50 +
  51 +static const struct clk_ops raspberrypi_firmware_clk_ops = {
  52 +       .is_prepared    = raspberrypi_fw_is_prepared,
  53 +       .recalc_rate    = raspberrypi_fw_get_rate,
  54 +       .round_rate     = raspberrypi_fw_dumb_round_rate,
  55 +       .set_rate       = raspberrypi_fw_set_rate,
  56 +};
  57 +
  58 +static struct clk_hw *raspberrypi_clk_register(struct raspberrypi_clk *rpi,
  59 +                                              unsigned int parent,
  60 +                                              unsigned int id)
  61 +{
  62 +       struct raspberrypi_clk_data *data;
  63 +       struct clk_init_data init = {};
  64 +       int ret;
  65 +
  66 +       if (id == RPI_FIRMWARE_ARM_CLK_ID) {
  67 +               struct clk_hw *hw;
  68 +
  69 +               hw = raspberrypi_register_pllb(rpi);
  70 +               if (IS_ERR(hw)) {
  71 +                       dev_err(rpi->dev, "Failed to initialize pllb, %ld\n",
  72 +                               PTR_ERR(hw));
  73 +                       return hw;
  74 +               }
  75 +
  76 +               return raspberrypi_register_pllb_arm(rpi);
  77 +       }
  78 +
  79 +       data = devm_kzalloc(rpi->dev, sizeof(*data), GFP_KERNEL);
  80 +       if (!data)
  81 +               return ERR_PTR(-ENOMEM);
  82 +       data->rpi = rpi;
  83 +       data->id = id;
  84 +
  85 +       init.name = devm_kasprintf(rpi->dev, GFP_KERNEL, "fw-clk-%u", id);
  86 +       init.ops = &raspberrypi_firmware_clk_ops;
  87 +       init.flags = CLK_GET_RATE_NOCACHE;
  88 +
  89 +       data->hw.init = &init;
  90 +
  91 +       ret = devm_clk_hw_register(rpi->dev, &data->hw);
  92 +       if (ret)
  93 +               return ERR_PTR(ret);
  94 +
  95 +       return &data->hw;
  96 +}
  97 +
  98 +static int raspberrypi_discover_clocks(struct raspberrypi_clk *rpi,
  99 +                                      struct clk_hw_onecell_data *data)
 100 +{
 101 +       struct rpi_firmware_get_clocks_response *clks;
 102 +       int ret;
 103 +
 104 +       clks = devm_kcalloc(rpi->dev, sizeof(*clks), NUM_FW_CLKS, GFP_KERNEL);
 105 +       if (!clks)
 106 +               return -ENOMEM;
 107 +
 108 +       ret = rpi_firmware_property(rpi->firmware, RPI_FIRMWARE_GET_CLOCKS,
 109 +                                   clks, sizeof(*clks) * NUM_FW_CLKS);
 110 +       if (ret)
 111 +               return ret;
 112 +
 113 +       while (clks->id) {
 114 +               struct clk_hw *hw;
 115 +
 116 +               hw = raspberrypi_clk_register(rpi, clks->parent, clks->id);
 117 +               if (IS_ERR(hw))
 118 +                       return PTR_ERR(hw);
 119 +
 120 +               data->hws[clks->id] = hw;
 121 +               data->num = clks->id + 1;
 122 +               clks++;
 123 +       }
 124 +
 125 +       return 0;
 126 +}
 127 +
 128  static int raspberrypi_clk_probe(struct platform_device *pdev)
 129  {
 130         struct clk_hw_onecell_data *clk_data;
 131 @@ -292,7 +381,6 @@ static int raspberrypi_clk_probe(struct
 132         struct device *dev = &pdev->dev;
 133         struct rpi_firmware *firmware;
 134         struct raspberrypi_clk *rpi;
 135 -       struct clk_hw *hw;
 136         int ret;
 137
 138         firmware_node = of_parse_phandle(dev->of_node, "raspberrypi,firmware", 0);
 139 @@ -318,17 +406,9 @@ static int raspberrypi_clk_probe(struct
 140         if (!clk_data)
 141                 return -ENOMEM;
 142
 143 -       hw = raspberrypi_register_pllb(rpi);
 144 -       if (IS_ERR(hw)) {
 145 -               dev_err(dev, "Failed to initialize pllb, %ld\n", PTR_ERR(hw));
 146 -               return PTR_ERR(hw);
 147 -       }
 148 -
 149 -       hw = raspberrypi_register_pllb_arm(rpi);
 150 -       if (IS_ERR(hw))
 151 -               return PTR_ERR(hw);
 152 -       clk_data->hws[RPI_FIRMWARE_ARM_CLK_ID] = hw;
 153 -       clk_data->num = RPI_FIRMWARE_ARM_CLK_ID + 1;
 154 +       ret = raspberrypi_discover_clocks(rpi, clk_data);
 155 +       if (ret)
 156 +               return ret;
 157
 158         ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
 159                                           clk_data);
 160 --- a/include/soc/bcm2835/raspberrypi-firmware.h
 161 +++ b/include/soc/bcm2835/raspberrypi-firmware.h
 162 @@ -160,6 +160,11 @@ enum rpi_firmware_property_tag {
 163
 164  #define GET_DISPLAY_SETTINGS_PAYLOAD_SIZE 64
 165
 166 +struct rpi_firmware_get_clocks_response {
 167 +       __le32 parent;
 168 +       __le32 id;
 169 +};
 170 +
 171  #if IS_ENABLED(CONFIG_RASPBERRYPI_FIRMWARE)
 172  int rpi_firmware_property(struct rpi_firmware *fw,
 173                           u32 tag, void *data, size_t len);