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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 | ||
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 | ||
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 | ||
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 | ||
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; | |
836ee0f7 | 78 | const char *name = clk_hw_get_name(&br->clkr.hw); |
6e0ad1b6 SB |
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 | ||
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 | ||
120 | static int clk_branch_enable(struct clk_hw *hw) | |
121 | { | |
122 | return clk_branch_toggle(hw, true, clk_branch_check_halt); | |
123 | } | |
124 | ||
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 | ||
137 | static int clk_branch2_enable(struct clk_hw *hw) | |
138 | { | |
139 | return clk_branch_toggle(hw, true, clk_branch2_check_halt); | |
140 | } | |
141 | ||
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); |