1 /*
2 * Copyright (c) 2013, The Linux Foundation. All rights reserved.
3 *
4 * This software is licensed under the terms of the GNU General Public
5 * License version 2, as published by the Free Software Foundation, and
6 * may be copied, distributed, and modified under those terms.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14 #include <linux/kernel.h>
15 #include <linux/bitops.h>
16 #include <linux/err.h>
17 #include <linux/delay.h>
18 #include <linux/export.h>
19 #include <linux/clk-provider.h>
20 #include <linux/regmap.h>
21
22 #include "clk-branch.h"
23
clk_branch_in_hwcg_mode(const struct clk_branch * br)24 static bool clk_branch_in_hwcg_mode(const struct clk_branch *br)
25 {
26 u32 val;
27
28 if (!br->hwcg_reg)
29 return 0;
30
31 regmap_read(br->clkr.regmap, br->hwcg_reg, &val);
32
33 return !!(val & BIT(br->hwcg_bit));
34 }
35
clk_branch_check_halt(const struct clk_branch * br,bool enabling)36 static bool clk_branch_check_halt(const struct clk_branch *br, bool enabling)
37 {
38 bool invert = (br->halt_check == BRANCH_HALT_ENABLE);
39 u32 val;
40
41 regmap_read(br->clkr.regmap, br->halt_reg, &val);
42
43 val &= BIT(br->halt_bit);
44 if (invert)
45 val = !val;
46
47 return !!val == !enabling;
48 }
49
50 #define BRANCH_CLK_OFF BIT(31)
51 #define BRANCH_NOC_FSM_STATUS_SHIFT 28
52 #define BRANCH_NOC_FSM_STATUS_MASK 0x7
53 #define BRANCH_NOC_FSM_STATUS_ON (0x2 << BRANCH_NOC_FSM_STATUS_SHIFT)
54
clk_branch2_check_halt(const struct clk_branch * br,bool enabling)55 static bool clk_branch2_check_halt(const struct clk_branch *br, bool enabling)
56 {
57 u32 val;
58 u32 mask;
59
60 mask = BRANCH_NOC_FSM_STATUS_MASK << BRANCH_NOC_FSM_STATUS_SHIFT;
61 mask |= BRANCH_CLK_OFF;
62
63 regmap_read(br->clkr.regmap, br->halt_reg, &val);
64
65 if (enabling) {
66 val &= mask;
67 return (val & BRANCH_CLK_OFF) == 0 ||
68 val == BRANCH_NOC_FSM_STATUS_ON;
69 } else {
70 return val & BRANCH_CLK_OFF;
71 }
72 }
73
clk_branch_wait(const struct clk_branch * br,bool enabling,bool (check_halt)(const struct clk_branch *,bool))74 static int clk_branch_wait(const struct clk_branch *br, bool enabling,
75 bool (check_halt)(const struct clk_branch *, bool))
76 {
77 bool voted = br->halt_check & BRANCH_VOTED;
78 const char *name = clk_hw_get_name(&br->clkr.hw);
79
80 /* Skip checking halt bit if the clock is in hardware gated mode */
81 if (clk_branch_in_hwcg_mode(br))
82 return 0;
83
84 if (br->halt_check == BRANCH_HALT_DELAY || (!enabling && voted)) {
85 udelay(10);
86 } else if (br->halt_check == BRANCH_HALT_ENABLE ||
87 br->halt_check == BRANCH_HALT ||
88 (enabling && voted)) {
89 int count = 200;
90
91 while (count-- > 0) {
92 if (check_halt(br, enabling))
93 return 0;
94 udelay(1);
95 }
96 WARN(1, "%s status stuck at 'o%s'", name,
97 enabling ? "ff" : "n");
98 return -EBUSY;
99 }
100 return 0;
101 }
102
clk_branch_toggle(struct clk_hw * hw,bool en,bool (check_halt)(const struct clk_branch *,bool))103 static int clk_branch_toggle(struct clk_hw *hw, bool en,
104 bool (check_halt)(const struct clk_branch *, bool))
105 {
106 struct clk_branch *br = to_clk_branch(hw);
107 int ret;
108
109 if (en) {
110 ret = clk_enable_regmap(hw);
111 if (ret)
112 return ret;
113 } else {
114 clk_disable_regmap(hw);
115 }
116
117 return clk_branch_wait(br, en, check_halt);
118 }
119
clk_branch_enable(struct clk_hw * hw)120 static int clk_branch_enable(struct clk_hw *hw)
121 {
122 return clk_branch_toggle(hw, true, clk_branch_check_halt);
123 }
124
clk_branch_disable(struct clk_hw * hw)125 static void clk_branch_disable(struct clk_hw *hw)
126 {
127 clk_branch_toggle(hw, false, clk_branch_check_halt);
128 }
129
130 const struct clk_ops clk_branch_ops = {
131 .enable = clk_branch_enable,
132 .disable = clk_branch_disable,
133 .is_enabled = clk_is_enabled_regmap,
134 };
135 EXPORT_SYMBOL_GPL(clk_branch_ops);
136
clk_branch2_enable(struct clk_hw * hw)137 static int clk_branch2_enable(struct clk_hw *hw)
138 {
139 return clk_branch_toggle(hw, true, clk_branch2_check_halt);
140 }
141
clk_branch2_disable(struct clk_hw * hw)142 static void clk_branch2_disable(struct clk_hw *hw)
143 {
144 clk_branch_toggle(hw, false, clk_branch2_check_halt);
145 }
146
147 const struct clk_ops clk_branch2_ops = {
148 .enable = clk_branch2_enable,
149 .disable = clk_branch2_disable,
150 .is_enabled = clk_is_enabled_regmap,
151 };
152 EXPORT_SYMBOL_GPL(clk_branch2_ops);
153
154 const struct clk_ops clk_branch_simple_ops = {
155 .enable = clk_enable_regmap,
156 .disable = clk_disable_regmap,
157 .is_enabled = clk_is_enabled_regmap,
158 };
159 EXPORT_SYMBOL_GPL(clk_branch_simple_ops);
160