Commit | Line | Data |
---|---|---|
2a4bd9f0 AL |
1 | /* |
2 | * kirkwood_freq.c: cpufreq driver for the Marvell kirkwood | |
3 | * | |
4 | * Copyright (C) 2013 Andrew Lunn <andrew@lunn.ch> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/clk.h> | |
15 | #include <linux/clk-provider.h> | |
16 | #include <linux/cpufreq.h> | |
e768f350 | 17 | #include <linux/of_device.h> |
2a4bd9f0 AL |
18 | #include <linux/platform_device.h> |
19 | #include <linux/io.h> | |
20 | #include <asm/proc-fns.h> | |
21 | ||
22 | #define CPU_SW_INT_BLK BIT(28) | |
23 | ||
24 | static struct priv | |
25 | { | |
26 | struct clk *cpu_clk; | |
27 | struct clk *ddr_clk; | |
28 | struct clk *powersave_clk; | |
29 | struct device *dev; | |
30 | void __iomem *base; | |
31 | } priv; | |
32 | ||
33 | #define STATE_CPU_FREQ 0x01 | |
34 | #define STATE_DDR_FREQ 0x02 | |
35 | ||
36 | /* | |
37 | * Kirkwood can swap the clock to the CPU between two clocks: | |
38 | * | |
39 | * - cpu clk | |
40 | * - ddr clk | |
41 | * | |
42 | * The frequencies are set at runtime before registering this * | |
43 | * table. | |
44 | */ | |
45 | static struct cpufreq_frequency_table kirkwood_freq_table[] = { | |
7f4b0461 VK |
46 | {0, STATE_CPU_FREQ, 0}, /* CPU uses cpuclk */ |
47 | {0, STATE_DDR_FREQ, 0}, /* CPU uses ddrclk */ | |
48 | {0, 0, CPUFREQ_TABLE_END}, | |
2a4bd9f0 AL |
49 | }; |
50 | ||
51 | static unsigned int kirkwood_cpufreq_get_cpu_frequency(unsigned int cpu) | |
52 | { | |
53 | if (__clk_is_enabled(priv.powersave_clk)) | |
54 | return kirkwood_freq_table[1].frequency; | |
55 | return kirkwood_freq_table[0].frequency; | |
56 | } | |
57 | ||
9c0ebcf7 VK |
58 | static int kirkwood_cpufreq_target(struct cpufreq_policy *policy, |
59 | unsigned int index) | |
2a4bd9f0 | 60 | { |
50701588 | 61 | unsigned int state = kirkwood_freq_table[index].driver_data; |
2a4bd9f0 AL |
62 | unsigned long reg; |
63 | ||
d4019f0a | 64 | local_irq_disable(); |
2a4bd9f0 | 65 | |
d4019f0a VK |
66 | /* Disable interrupts to the CPU */ |
67 | reg = readl_relaxed(priv.base); | |
68 | reg |= CPU_SW_INT_BLK; | |
69 | writel_relaxed(reg, priv.base); | |
2a4bd9f0 | 70 | |
d4019f0a VK |
71 | switch (state) { |
72 | case STATE_CPU_FREQ: | |
73 | clk_disable(priv.powersave_clk); | |
74 | break; | |
75 | case STATE_DDR_FREQ: | |
76 | clk_enable(priv.powersave_clk); | |
77 | break; | |
78 | } | |
2a4bd9f0 | 79 | |
d4019f0a VK |
80 | /* Wait-for-Interrupt, while the hardware changes frequency */ |
81 | cpu_do_idle(); | |
2a4bd9f0 | 82 | |
d4019f0a VK |
83 | /* Enable interrupts to the CPU */ |
84 | reg = readl_relaxed(priv.base); | |
85 | reg &= ~CPU_SW_INT_BLK; | |
86 | writel_relaxed(reg, priv.base); | |
2a4bd9f0 | 87 | |
d4019f0a | 88 | local_irq_enable(); |
2a4bd9f0 AL |
89 | |
90 | return 0; | |
91 | } | |
92 | ||
93 | /* Module init and exit code */ | |
94 | static int kirkwood_cpufreq_cpu_init(struct cpufreq_policy *policy) | |
95 | { | |
fa6fa663 | 96 | return cpufreq_generic_init(policy, kirkwood_freq_table, 5000); |
2a4bd9f0 AL |
97 | } |
98 | ||
2a4bd9f0 | 99 | static struct cpufreq_driver kirkwood_cpufreq_driver = { |
ae6b4271 | 100 | .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, |
2a4bd9f0 | 101 | .get = kirkwood_cpufreq_get_cpu_frequency, |
a86a41a1 | 102 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 103 | .target_index = kirkwood_cpufreq_target, |
2a4bd9f0 | 104 | .init = kirkwood_cpufreq_cpu_init, |
2a4bd9f0 | 105 | .name = "kirkwood-cpufreq", |
a86a41a1 | 106 | .attr = cpufreq_generic_attr, |
2a4bd9f0 AL |
107 | }; |
108 | ||
109 | static int kirkwood_cpufreq_probe(struct platform_device *pdev) | |
110 | { | |
111 | struct device_node *np; | |
112 | struct resource *res; | |
113 | int err; | |
114 | ||
115 | priv.dev = &pdev->dev; | |
116 | ||
117 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
cc721c4f SMP |
118 | priv.base = devm_ioremap_resource(&pdev->dev, res); |
119 | if (IS_ERR(priv.base)) | |
120 | return PTR_ERR(priv.base); | |
2a4bd9f0 | 121 | |
e768f350 SK |
122 | np = of_cpu_device_node_get(0); |
123 | if (!np) { | |
124 | dev_err(&pdev->dev, "failed to get cpu device node\n"); | |
2a4bd9f0 | 125 | return -ENODEV; |
e768f350 | 126 | } |
2a4bd9f0 AL |
127 | |
128 | priv.cpu_clk = of_clk_get_by_name(np, "cpu_clk"); | |
129 | if (IS_ERR(priv.cpu_clk)) { | |
130 | dev_err(priv.dev, "Unable to get cpuclk"); | |
131 | return PTR_ERR(priv.cpu_clk); | |
132 | } | |
133 | ||
134 | clk_prepare_enable(priv.cpu_clk); | |
135 | kirkwood_freq_table[0].frequency = clk_get_rate(priv.cpu_clk) / 1000; | |
136 | ||
137 | priv.ddr_clk = of_clk_get_by_name(np, "ddrclk"); | |
138 | if (IS_ERR(priv.ddr_clk)) { | |
139 | dev_err(priv.dev, "Unable to get ddrclk"); | |
140 | err = PTR_ERR(priv.ddr_clk); | |
141 | goto out_cpu; | |
142 | } | |
143 | ||
144 | clk_prepare_enable(priv.ddr_clk); | |
145 | kirkwood_freq_table[1].frequency = clk_get_rate(priv.ddr_clk) / 1000; | |
146 | ||
147 | priv.powersave_clk = of_clk_get_by_name(np, "powersave"); | |
148 | if (IS_ERR(priv.powersave_clk)) { | |
149 | dev_err(priv.dev, "Unable to get powersave"); | |
150 | err = PTR_ERR(priv.powersave_clk); | |
151 | goto out_ddr; | |
152 | } | |
153 | clk_prepare(priv.powersave_clk); | |
154 | ||
155 | of_node_put(np); | |
156 | np = NULL; | |
157 | ||
158 | err = cpufreq_register_driver(&kirkwood_cpufreq_driver); | |
159 | if (!err) | |
160 | return 0; | |
161 | ||
162 | dev_err(priv.dev, "Failed to register cpufreq driver"); | |
163 | ||
164 | clk_disable_unprepare(priv.powersave_clk); | |
165 | out_ddr: | |
166 | clk_disable_unprepare(priv.ddr_clk); | |
167 | out_cpu: | |
168 | clk_disable_unprepare(priv.cpu_clk); | |
169 | of_node_put(np); | |
170 | ||
171 | return err; | |
172 | } | |
173 | ||
174 | static int kirkwood_cpufreq_remove(struct platform_device *pdev) | |
175 | { | |
176 | cpufreq_unregister_driver(&kirkwood_cpufreq_driver); | |
177 | ||
178 | clk_disable_unprepare(priv.powersave_clk); | |
179 | clk_disable_unprepare(priv.ddr_clk); | |
180 | clk_disable_unprepare(priv.cpu_clk); | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
185 | static struct platform_driver kirkwood_cpufreq_platform_driver = { | |
186 | .probe = kirkwood_cpufreq_probe, | |
187 | .remove = kirkwood_cpufreq_remove, | |
188 | .driver = { | |
189 | .name = "kirkwood-cpufreq", | |
190 | .owner = THIS_MODULE, | |
191 | }, | |
192 | }; | |
193 | ||
194 | module_platform_driver(kirkwood_cpufreq_platform_driver); | |
195 | ||
196 | MODULE_LICENSE("GPL v2"); | |
197 | MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch"); | |
198 | MODULE_DESCRIPTION("cpufreq driver for Marvell's kirkwood CPU"); | |
199 | MODULE_ALIAS("platform:kirkwood-cpufreq"); |