target/linux/ipq806x/patches-4.19/0034-0012-clk-qcom-Add-safe-switch-hook-for-krait-mux-clocks.patch

   1 From 77612720a2362230af726baa4149c40ec7a7fb05 Mon Sep 17 00:00:00 2001
   2 From: Sricharan R <sricharan@codeaurora.org>
   3 Date: Tue, 14 Aug 2018 17:42:31 +0530
   4 Subject: [PATCH 12/12] clk: qcom: Add safe switch hook for krait mux clocks
   5
   6 When the Hfplls are reprogrammed during the rate change,
   7 the primary muxes which are sourced from the same hfpll
   8 for higher frequencies, needs to be switched to the 'safe
   9 secondary mux' as the parent for that small window. This
  10 is done by registering a clk notifier for the muxes and
  11 switching to the safe parent in the PRE_RATE_CHANGE notifier
  12 and back to the original parent in the POST_RATE_CHANGE notifier.
  13
  14 Signed-off-by: Sricharan R <sricharan@codeaurora.org>
  15 Tested-by: Craig Tatlor <ctatlor97@gmail.com>
  16 Signed-off-by: Stephen Boyd <sboyd@kernel.org>
  17 ---
  18  drivers/clk/qcom/clk-krait.c |  2 ++
  19  drivers/clk/qcom/clk-krait.h |  3 ++
  20  drivers/clk/qcom/krait-cc.c  | 56 ++++++++++++++++++++++++++++++++++++
  21  3 files changed, 61 insertions(+)
  22
  23 --- a/drivers/clk/qcom/clk-krait.c
  24 +++ b/drivers/clk/qcom/clk-krait.c
  25 @@ -50,6 +50,8 @@ static int krait_mux_set_parent(struct c
  26         if (__clk_is_enabled(hw->clk))
  27                 __krait_mux_set_sel(mux, sel);
  28
  29 +       mux->reparent = true;
  30 +
  31         return 0;
  32  }
  33
  34 --- a/drivers/clk/qcom/clk-krait.h
  35 +++ b/drivers/clk/qcom/clk-krait.h
  36 @@ -12,6 +12,9 @@ struct krait_mux_clk {
  37         u32             shift;
  38         u32             en_mask;
  39         bool            lpl;
  40 +       u8              safe_sel;
  41 +       u8              old_index;
  42 +       bool            reparent;
  43
  44         struct clk_hw   hw;
  45         struct notifier_block   clk_nb;
  46 --- a/drivers/clk/qcom/krait-cc.c
  47 +++ b/drivers/clk/qcom/krait-cc.c
  48 @@ -26,6 +26,49 @@ static unsigned int pri_mux_map[] = {
  49         0,
  50  };
  51
  52 +/*
  53 + * Notifier function for switching the muxes to safe parent
  54 + * while the hfpll is getting reprogrammed.
  55 + */
  56 +static int krait_notifier_cb(struct notifier_block *nb,
  57 +                            unsigned long event,
  58 +                            void *data)
  59 +{
  60 +       int ret = 0;
  61 +       struct krait_mux_clk *mux = container_of(nb, struct krait_mux_clk,
  62 +                                                clk_nb);
  63 +       /* Switch to safe parent */
  64 +       if (event == PRE_RATE_CHANGE) {
  65 +               mux->old_index = krait_mux_clk_ops.get_parent(&mux->hw);
  66 +               ret = krait_mux_clk_ops.set_parent(&mux->hw, mux->safe_sel);
  67 +               mux->reparent = false;
  68 +       /*
  69 +        * By the time POST_RATE_CHANGE notifier is called,
  70 +        * clk framework itself would have changed the parent for the new rate.
  71 +        * Only otherwise, put back to the old parent.
  72 +        */
  73 +       } else if (event == POST_RATE_CHANGE) {
  74 +               if (!mux->reparent)
  75 +                       ret = krait_mux_clk_ops.set_parent(&mux->hw,
  76 +                                                          mux->old_index);
  77 +       }
  78 +
  79 +       return notifier_from_errno(ret);
  80 +}
  81 +
  82 +static int krait_notifier_register(struct device *dev, struct clk *clk,
  83 +                                  struct krait_mux_clk *mux)
  84 +{
  85 +       int ret = 0;
  86 +
  87 +       mux->clk_nb.notifier_call = krait_notifier_cb;
  88 +       ret = clk_notifier_register(clk, &mux->clk_nb);
  89 +       if (ret)
  90 +               dev_err(dev, "failed to register clock notifier: %d\n", ret);
  91 +
  92 +       return ret;
  93 +}
  94 +
  95  static int
  96  krait_add_div(struct device *dev, int id, const char *s, unsigned int offset)
  97  {
  98 @@ -70,6 +113,7 @@ static int
  99  krait_add_sec_mux(struct device *dev, int id, const char *s,
 100                   unsigned int offset, bool unique_aux)
 101  {
 102 +       int ret;
 103         struct krait_mux_clk *mux;
 104         static const char *sec_mux_list[] = {
 105                 "acpu_aux",
 106 @@ -93,6 +137,7 @@ krait_add_sec_mux(struct device *dev, in
 107         mux->shift = 2;
 108         mux->parent_map = sec_mux_map;
 109         mux->hw.init = &init;
 110 +       mux->safe_sel = 0;
 111
 112         init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
 113         if (!init.name)
 114 @@ -108,6 +153,11 @@ krait_add_sec_mux(struct device *dev, in
 115
 116         clk = devm_clk_register(dev, &mux->hw);
 117
 118 +       ret = krait_notifier_register(dev, clk, mux);
 119 +       if (ret)
 120 +               goto unique_aux;
 121 +
 122 +unique_aux:
 123         if (unique_aux)
 124                 kfree(sec_mux_list[0]);
 125  err_aux:
 126 @@ -119,6 +169,7 @@ static struct clk *
 127  krait_add_pri_mux(struct device *dev, int id, const char *s,
 128                   unsigned int offset)
 129  {
 130 +       int ret;
 131         struct krait_mux_clk *mux;
 132         const char *p_names[3];
 133         struct clk_init_data init = {
 134 @@ -139,6 +190,7 @@ krait_add_pri_mux(struct device *dev, in
 135         mux->lpl = id >= 0;
 136         mux->parent_map = pri_mux_map;
 137         mux->hw.init = &init;
 138 +       mux->safe_sel = 2;
 139
 140         init.name = kasprintf(GFP_KERNEL, "krait%s_pri_mux", s);
 141         if (!init.name)
 142 @@ -164,6 +216,10 @@ krait_add_pri_mux(struct device *dev, in
 143
 144         clk = devm_clk_register(dev, &mux->hw);
 145
 146 +       ret = krait_notifier_register(dev, clk, mux);
 147 +       if (ret)
 148 +               goto err_p3;
 149 +err_p3:
 150         kfree(p_names[2]);
 151  err_p2:
 152         kfree(p_names[1]);