drivers/clk/qcom/clk-branch.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/bitops.h>
   8 #include <linux/err.h>
   9 #include <linux/delay.h>
  10 #include <linux/export.h>
  11 #include <linux/clk-provider.h>
  12 #include <linux/regmap.h>
  13
  14 #include "clk-branch.h"
  15
  16 static bool clk_branch_in_hwcg_mode(const struct clk_branch *br)
  17 {
  18         u32 val;
  19
  20         if (!br->hwcg_reg)
  21                 return false;
  22
  23         regmap_read(br->clkr.regmap, br->hwcg_reg, &val);
  24
  25         return !!(val & BIT(br->hwcg_bit));
  26 }
  27
  28 static bool clk_branch_check_halt(const struct clk_branch *br, bool enabling)
  29 {
  30         bool invert = (br->halt_check == BRANCH_HALT_ENABLE);
  31         u32 val;
  32
  33         regmap_read(br->clkr.regmap, br->halt_reg, &val);
  34
  35         val &= BIT(br->halt_bit);
  36         if (invert)
  37                 val = !val;
  38
  39         return !!val == !enabling;
  40 }
  41
  42 static bool clk_branch2_check_halt(const struct clk_branch *br, bool enabling)
  43 {
  44         u32 val;
  45         u32 mask;
  46         bool invert = (br->halt_check == BRANCH_HALT_ENABLE);
  47
  48         mask = CBCR_NOC_FSM_STATUS;
  49         mask |= CBCR_CLK_OFF;
  50
  51         regmap_read(br->clkr.regmap, br->halt_reg, &val);
  52
  53         if (enabling) {
  54                 val &= mask;
  55                 return (val & CBCR_CLK_OFF) == (invert ? CBCR_CLK_OFF : 0) ||
  56                         FIELD_GET(CBCR_NOC_FSM_STATUS, val) == FSM_STATUS_ON;
  57         }
  58         return (val & CBCR_CLK_OFF) == (invert ? 0 : CBCR_CLK_OFF);
  59 }
  60
  61 static int clk_branch_wait(const struct clk_branch *br, bool enabling,
  62                 bool (check_halt)(const struct clk_branch *, bool))
  63 {
  64         bool voted = br->halt_check & BRANCH_VOTED;
  65         const char *name = clk_hw_get_name(&br->clkr.hw);
  66
  67         /*
  68          * Skip checking halt bit if we're explicitly ignoring the bit or the
  69          * clock is in hardware gated mode
  70          */
  71         if (br->halt_check == BRANCH_HALT_SKIP || clk_branch_in_hwcg_mode(br))
  72                 return 0;
  73
  74         if (br->halt_check == BRANCH_HALT_DELAY || (!enabling && voted)) {
  75                 udelay(10);
  76         } else if (br->halt_check == BRANCH_HALT_ENABLE ||
  77                    br->halt_check == BRANCH_HALT ||
  78                    (enabling && voted)) {
  79                 int count = 200;
  80
  81                 while (count-- > 0) {
  82                         if (check_halt(br, enabling))
  83                                 return 0;
  84                         udelay(1);
  85                 }
  86                 WARN(1, "%s status stuck at 'o%s'", name,
  87                                 enabling ? "ff" : "n");
  88                 return -EBUSY;
  89         }
  90         return 0;
  91 }
  92
  93 static int clk_branch_toggle(struct clk_hw *hw, bool en,
  94                 bool (check_halt)(const struct clk_branch *, bool))
  95 {
  96         struct clk_branch *br = to_clk_branch(hw);
  97         int ret;
  98
  99         if (en) {
 100                 ret = clk_enable_regmap(hw);
 101                 if (ret)
 102                         return ret;
 103         } else {
 104                 clk_disable_regmap(hw);
 105         }
 106
 107         return clk_branch_wait(br, en, check_halt);
 108 }
 109
 110 static int clk_branch_enable(struct clk_hw *hw)
 111 {
 112         return clk_branch_toggle(hw, true, clk_branch_check_halt);
 113 }
 114
 115 static void clk_branch_disable(struct clk_hw *hw)
 116 {
 117         clk_branch_toggle(hw, false, clk_branch_check_halt);
 118 }
 119
 120 const struct clk_ops clk_branch_ops = {
 121         .enable = clk_branch_enable,
 122         .disable = clk_branch_disable,
 123         .is_enabled = clk_is_enabled_regmap,
 124 };
 125 EXPORT_SYMBOL_GPL(clk_branch_ops);
 126
 127 static int clk_branch2_enable(struct clk_hw *hw)
 128 {
 129         return clk_branch_toggle(hw, true, clk_branch2_check_halt);
 130 }
 131
 132 static void clk_branch2_disable(struct clk_hw *hw)
 133 {
 134         clk_branch_toggle(hw, false, clk_branch2_check_halt);
 135 }
 136
 137 const struct clk_ops clk_branch2_ops = {
 138         .enable = clk_branch2_enable,
 139         .disable = clk_branch2_disable,
 140         .is_enabled = clk_is_enabled_regmap,
 141 };
 142 EXPORT_SYMBOL_GPL(clk_branch2_ops);
 143
 144 const struct clk_ops clk_branch2_aon_ops = {
 145         .enable = clk_branch2_enable,
 146         .is_enabled = clk_is_enabled_regmap,
 147 };
 148 EXPORT_SYMBOL_GPL(clk_branch2_aon_ops);
 149
 150 const struct clk_ops clk_branch_simple_ops = {
 151         .enable = clk_enable_regmap,
 152         .disable = clk_disable_regmap,
 153         .is_enabled = clk_is_enabled_regmap,
 154 };
 155 EXPORT_SYMBOL_GPL(clk_branch_simple_ops);