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a0a22cf1 KC |
1 | /* |
2 | * CPU Frequency Scaling for Loongson 1 SoC | |
3 | * | |
6a1d55cc | 4 | * Copyright (C) 2014-2016 Zhang, Keguang <keguang.zhang@gmail.com> |
a0a22cf1 KC |
5 | * |
6 | * This file is licensed under the terms of the GNU General Public | |
7 | * License version 2. This program is licensed "as is" without any | |
8 | * warranty of any kind, whether express or implied. | |
9 | */ | |
10 | ||
11 | #include <linux/clk.h> | |
12 | #include <linux/clk-provider.h> | |
13 | #include <linux/cpu.h> | |
14 | #include <linux/cpufreq.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/slab.h> | |
19 | ||
30ad29bb HC |
20 | #include <cpufreq.h> |
21 | #include <loongson1.h> | |
a0a22cf1 | 22 | |
99bf2e68 | 23 | struct ls1x_cpufreq { |
a0a22cf1 KC |
24 | struct device *dev; |
25 | struct clk *clk; /* CPU clk */ | |
26 | struct clk *mux_clk; /* MUX of CPU clk */ | |
27 | struct clk *pll_clk; /* PLL clk */ | |
28 | struct clk *osc_clk; /* OSC clk */ | |
29 | unsigned int max_freq; | |
30 | unsigned int min_freq; | |
99bf2e68 KC |
31 | }; |
32 | ||
33 | static struct ls1x_cpufreq *cpufreq; | |
a0a22cf1 KC |
34 | |
35 | static int ls1x_cpufreq_notifier(struct notifier_block *nb, | |
36 | unsigned long val, void *data) | |
37 | { | |
38 | if (val == CPUFREQ_POSTCHANGE) | |
39 | current_cpu_data.udelay_val = loops_per_jiffy; | |
40 | ||
41 | return NOTIFY_OK; | |
42 | } | |
43 | ||
44 | static struct notifier_block ls1x_cpufreq_notifier_block = { | |
45 | .notifier_call = ls1x_cpufreq_notifier | |
46 | }; | |
47 | ||
48 | static int ls1x_cpufreq_target(struct cpufreq_policy *policy, | |
49 | unsigned int index) | |
50 | { | |
99bf2e68 | 51 | struct device *cpu_dev = get_cpu_device(policy->cpu); |
a0a22cf1 KC |
52 | unsigned int old_freq, new_freq; |
53 | ||
54 | old_freq = policy->cur; | |
55 | new_freq = policy->freq_table[index].frequency; | |
56 | ||
57 | /* | |
58 | * The procedure of reconfiguring CPU clk is as below. | |
59 | * | |
60 | * - Reparent CPU clk to OSC clk | |
61 | * - Reset CPU clock (very important) | |
62 | * - Reconfigure CPU DIV | |
63 | * - Reparent CPU clk back to CPU DIV clk | |
64 | */ | |
65 | ||
99bf2e68 | 66 | clk_set_parent(policy->clk, cpufreq->osc_clk); |
a0a22cf1 KC |
67 | __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU, |
68 | LS1X_CLK_PLL_DIV); | |
69 | __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU), | |
70 | LS1X_CLK_PLL_DIV); | |
99bf2e68 KC |
71 | clk_set_rate(cpufreq->mux_clk, new_freq * 1000); |
72 | clk_set_parent(policy->clk, cpufreq->mux_clk); | |
73 | dev_dbg(cpu_dev, "%u KHz --> %u KHz\n", old_freq, new_freq); | |
a0a22cf1 KC |
74 | |
75 | return 0; | |
76 | } | |
77 | ||
78 | static int ls1x_cpufreq_init(struct cpufreq_policy *policy) | |
79 | { | |
99bf2e68 | 80 | struct device *cpu_dev = get_cpu_device(policy->cpu); |
a0a22cf1 KC |
81 | struct cpufreq_frequency_table *freq_tbl; |
82 | unsigned int pll_freq, freq; | |
83 | int steps, i, ret; | |
84 | ||
99bf2e68 | 85 | pll_freq = clk_get_rate(cpufreq->pll_clk) / 1000; |
a0a22cf1 KC |
86 | |
87 | steps = 1 << DIV_CPU_WIDTH; | |
379e38a7 KC |
88 | freq_tbl = kcalloc(steps, sizeof(*freq_tbl), GFP_KERNEL); |
89 | if (!freq_tbl) | |
90 | return -ENOMEM; | |
a0a22cf1 KC |
91 | |
92 | for (i = 0; i < (steps - 1); i++) { | |
93 | freq = pll_freq / (i + 1); | |
99bf2e68 | 94 | if ((freq < cpufreq->min_freq) || (freq > cpufreq->max_freq)) |
a0a22cf1 KC |
95 | freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID; |
96 | else | |
97 | freq_tbl[i].frequency = freq; | |
99bf2e68 | 98 | dev_dbg(cpu_dev, |
a0a22cf1 KC |
99 | "cpufreq table: index %d: frequency %d\n", i, |
100 | freq_tbl[i].frequency); | |
101 | } | |
102 | freq_tbl[i].frequency = CPUFREQ_TABLE_END; | |
103 | ||
99bf2e68 | 104 | policy->clk = cpufreq->clk; |
a0a22cf1 KC |
105 | ret = cpufreq_generic_init(policy, freq_tbl, 0); |
106 | if (ret) | |
107 | kfree(freq_tbl); | |
379e38a7 | 108 | |
a0a22cf1 KC |
109 | return ret; |
110 | } | |
111 | ||
112 | static int ls1x_cpufreq_exit(struct cpufreq_policy *policy) | |
113 | { | |
114 | kfree(policy->freq_table); | |
115 | return 0; | |
116 | } | |
117 | ||
118 | static struct cpufreq_driver ls1x_cpufreq_driver = { | |
119 | .name = "cpufreq-ls1x", | |
120 | .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, | |
121 | .verify = cpufreq_generic_frequency_table_verify, | |
122 | .target_index = ls1x_cpufreq_target, | |
123 | .get = cpufreq_generic_get, | |
124 | .init = ls1x_cpufreq_init, | |
125 | .exit = ls1x_cpufreq_exit, | |
126 | .attr = cpufreq_generic_attr, | |
127 | }; | |
128 | ||
129 | static int ls1x_cpufreq_remove(struct platform_device *pdev) | |
130 | { | |
131 | cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block, | |
132 | CPUFREQ_TRANSITION_NOTIFIER); | |
133 | cpufreq_unregister_driver(&ls1x_cpufreq_driver); | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
138 | static int ls1x_cpufreq_probe(struct platform_device *pdev) | |
139 | { | |
25581d2b | 140 | struct plat_ls1x_cpufreq *pdata = dev_get_platdata(&pdev->dev); |
a0a22cf1 KC |
141 | struct clk *clk; |
142 | int ret; | |
143 | ||
65b2849a KC |
144 | if (!pdata || !pdata->clk_name || !pdata->osc_clk_name) { |
145 | dev_err(&pdev->dev, "platform data missing\n"); | |
a0a22cf1 | 146 | return -EINVAL; |
65b2849a | 147 | } |
a0a22cf1 | 148 | |
99bf2e68 KC |
149 | cpufreq = |
150 | devm_kzalloc(&pdev->dev, sizeof(struct ls1x_cpufreq), GFP_KERNEL); | |
151 | if (!cpufreq) | |
152 | return -ENOMEM; | |
153 | ||
154 | cpufreq->dev = &pdev->dev; | |
a0a22cf1 KC |
155 | |
156 | clk = devm_clk_get(&pdev->dev, pdata->clk_name); | |
157 | if (IS_ERR(clk)) { | |
99bf2e68 | 158 | dev_err(&pdev->dev, "unable to get %s clock\n", |
a0a22cf1 | 159 | pdata->clk_name); |
65b2849a | 160 | return PTR_ERR(clk); |
a0a22cf1 | 161 | } |
99bf2e68 | 162 | cpufreq->clk = clk; |
a0a22cf1 KC |
163 | |
164 | clk = clk_get_parent(clk); | |
165 | if (IS_ERR(clk)) { | |
99bf2e68 KC |
166 | dev_err(&pdev->dev, "unable to get parent of %s clock\n", |
167 | __clk_get_name(cpufreq->clk)); | |
65b2849a | 168 | return PTR_ERR(clk); |
a0a22cf1 | 169 | } |
99bf2e68 | 170 | cpufreq->mux_clk = clk; |
a0a22cf1 KC |
171 | |
172 | clk = clk_get_parent(clk); | |
173 | if (IS_ERR(clk)) { | |
99bf2e68 KC |
174 | dev_err(&pdev->dev, "unable to get parent of %s clock\n", |
175 | __clk_get_name(cpufreq->mux_clk)); | |
65b2849a | 176 | return PTR_ERR(clk); |
a0a22cf1 | 177 | } |
99bf2e68 | 178 | cpufreq->pll_clk = clk; |
a0a22cf1 KC |
179 | |
180 | clk = devm_clk_get(&pdev->dev, pdata->osc_clk_name); | |
181 | if (IS_ERR(clk)) { | |
99bf2e68 | 182 | dev_err(&pdev->dev, "unable to get %s clock\n", |
a0a22cf1 | 183 | pdata->osc_clk_name); |
65b2849a | 184 | return PTR_ERR(clk); |
a0a22cf1 | 185 | } |
99bf2e68 | 186 | cpufreq->osc_clk = clk; |
a0a22cf1 | 187 | |
99bf2e68 KC |
188 | cpufreq->max_freq = pdata->max_freq; |
189 | cpufreq->min_freq = pdata->min_freq; | |
a0a22cf1 KC |
190 | |
191 | ret = cpufreq_register_driver(&ls1x_cpufreq_driver); | |
192 | if (ret) { | |
99bf2e68 KC |
193 | dev_err(&pdev->dev, |
194 | "failed to register CPUFreq driver: %d\n", ret); | |
65b2849a | 195 | return ret; |
a0a22cf1 KC |
196 | } |
197 | ||
198 | ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block, | |
199 | CPUFREQ_TRANSITION_NOTIFIER); | |
200 | ||
65b2849a KC |
201 | if (ret) { |
202 | dev_err(&pdev->dev, | |
203 | "failed to register CPUFreq notifier: %d\n",ret); | |
204 | cpufreq_unregister_driver(&ls1x_cpufreq_driver); | |
205 | } | |
a0a22cf1 | 206 | |
a0a22cf1 KC |
207 | return ret; |
208 | } | |
209 | ||
210 | static struct platform_driver ls1x_cpufreq_platdrv = { | |
6a1d55cc KC |
211 | .probe = ls1x_cpufreq_probe, |
212 | .remove = ls1x_cpufreq_remove, | |
213 | .driver = { | |
a0a22cf1 | 214 | .name = "ls1x-cpufreq", |
a0a22cf1 | 215 | }, |
a0a22cf1 KC |
216 | }; |
217 | ||
218 | module_platform_driver(ls1x_cpufreq_platdrv); | |
219 | ||
220 | MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>"); | |
6a1d55cc | 221 | MODULE_DESCRIPTION("Loongson1 CPUFreq driver"); |
a0a22cf1 | 222 | MODULE_LICENSE("GPL"); |