Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Cpufreq driver for the loongson-2 processors |
| 3 | * |
| 4 | * The 2E revision of loongson processor not support this feature. |
| 5 | * |
| 6 | * Copyright (C) 2006 - 2008 Lemote Inc. & Insititute of Computing Technology |
| 7 | * Author: Yanhua, yanh@lemote.com |
| 8 | * |
| 9 | * This file is subject to the terms and conditions of the GNU General Public |
| 10 | * License. See the file "COPYING" in the main directory of this archive |
| 11 | * for more details. |
| 12 | */ |
| 13 | #include <linux/cpufreq.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/err.h> |
| 16 | #include <linux/sched.h> /* set_cpus_allowed() */ |
| 17 | #include <linux/delay.h> |
| 18 | #include <linux/platform_device.h> |
| 19 | |
| 20 | #include <asm/clock.h> |
| 21 | |
Ralf Baechle | 95cf146 | 2012-08-01 17:15:32 +0200 | [diff] [blame] | 22 | #include <asm/mach-loongson/loongson.h> |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 23 | |
| 24 | static uint nowait; |
| 25 | |
| 26 | static struct clk *cpuclk; |
| 27 | |
| 28 | static void (*saved_cpu_wait) (void); |
| 29 | |
| 30 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, |
| 31 | unsigned long val, void *data); |
| 32 | |
| 33 | static struct notifier_block loongson2_cpufreq_notifier_block = { |
| 34 | .notifier_call = loongson2_cpu_freq_notifier |
| 35 | }; |
| 36 | |
| 37 | static int loongson2_cpu_freq_notifier(struct notifier_block *nb, |
| 38 | unsigned long val, void *data) |
| 39 | { |
| 40 | if (val == CPUFREQ_POSTCHANGE) |
| 41 | current_cpu_data.udelay_val = loops_per_jiffy; |
| 42 | |
| 43 | return 0; |
| 44 | } |
| 45 | |
| 46 | static unsigned int loongson2_cpufreq_get(unsigned int cpu) |
| 47 | { |
| 48 | return clk_get_rate(cpuclk); |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * Here we notify other drivers of the proposed change and the final change. |
| 53 | */ |
| 54 | static int loongson2_cpufreq_target(struct cpufreq_policy *policy, |
| 55 | unsigned int target_freq, |
| 56 | unsigned int relation) |
| 57 | { |
| 58 | unsigned int cpu = policy->cpu; |
| 59 | unsigned int newstate = 0; |
| 60 | cpumask_t cpus_allowed; |
| 61 | struct cpufreq_freqs freqs; |
| 62 | unsigned int freq; |
| 63 | |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 64 | cpus_allowed = current->cpus_allowed; |
Julia Lawall | ed1bbde | 2010-03-26 23:03:07 +0100 | [diff] [blame] | 65 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 66 | |
| 67 | if (cpufreq_frequency_table_target |
| 68 | (policy, &loongson2_clockmod_table[0], target_freq, relation, |
| 69 | &newstate)) |
| 70 | return -EINVAL; |
| 71 | |
| 72 | freq = |
| 73 | ((cpu_clock_freq / 1000) * |
| 74 | loongson2_clockmod_table[newstate].index) / 8; |
| 75 | if (freq < policy->min || freq > policy->max) |
| 76 | return -EINVAL; |
| 77 | |
| 78 | pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); |
| 79 | |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 80 | freqs.old = loongson2_cpufreq_get(cpu); |
| 81 | freqs.new = freq; |
| 82 | freqs.flags = 0; |
| 83 | |
| 84 | if (freqs.new == freqs.old) |
| 85 | return 0; |
| 86 | |
| 87 | /* notifiers */ |
Viresh Kumar | b43a7ff | 2013-03-24 11:56:43 +0530 | [diff] [blame] | 88 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 89 | |
Julia Lawall | ed1bbde | 2010-03-26 23:03:07 +0100 | [diff] [blame] | 90 | set_cpus_allowed_ptr(current, &cpus_allowed); |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 91 | |
| 92 | /* setting the cpu frequency */ |
| 93 | clk_set_rate(cpuclk, freq); |
| 94 | |
| 95 | /* notifiers */ |
Viresh Kumar | b43a7ff | 2013-03-24 11:56:43 +0530 | [diff] [blame] | 96 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 97 | |
| 98 | pr_debug("cpufreq: set frequency %u kHz\n", freq); |
| 99 | |
| 100 | return 0; |
| 101 | } |
| 102 | |
| 103 | static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) |
| 104 | { |
| 105 | int i; |
Julia Lawall | 42913c7 | 2013-01-03 09:34:20 +0000 | [diff] [blame] | 106 | unsigned long rate; |
| 107 | int ret; |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 108 | |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 109 | cpuclk = clk_get(NULL, "cpu_clk"); |
| 110 | if (IS_ERR(cpuclk)) { |
| 111 | printk(KERN_ERR "cpufreq: couldn't get CPU clk\n"); |
| 112 | return PTR_ERR(cpuclk); |
| 113 | } |
| 114 | |
Julia Lawall | 42913c7 | 2013-01-03 09:34:20 +0000 | [diff] [blame] | 115 | rate = cpu_clock_freq / 1000; |
| 116 | if (!rate) { |
| 117 | clk_put(cpuclk); |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 118 | return -EINVAL; |
Julia Lawall | 42913c7 | 2013-01-03 09:34:20 +0000 | [diff] [blame] | 119 | } |
| 120 | ret = clk_set_rate(cpuclk, rate); |
| 121 | if (ret) { |
| 122 | clk_put(cpuclk); |
| 123 | return ret; |
| 124 | } |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 125 | |
| 126 | /* clock table init */ |
| 127 | for (i = 2; |
| 128 | (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); |
| 129 | i++) |
Julia Lawall | 42913c7 | 2013-01-03 09:34:20 +0000 | [diff] [blame] | 130 | loongson2_clockmod_table[i].frequency = (rate * i) / 8; |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 131 | |
| 132 | policy->cur = loongson2_cpufreq_get(policy->cpu); |
| 133 | |
| 134 | cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0], |
| 135 | policy->cpu); |
| 136 | |
| 137 | return cpufreq_frequency_table_cpuinfo(policy, |
| 138 | &loongson2_clockmod_table[0]); |
| 139 | } |
| 140 | |
| 141 | static int loongson2_cpufreq_verify(struct cpufreq_policy *policy) |
| 142 | { |
| 143 | return cpufreq_frequency_table_verify(policy, |
| 144 | &loongson2_clockmod_table[0]); |
| 145 | } |
| 146 | |
| 147 | static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) |
| 148 | { |
| 149 | clk_put(cpuclk); |
| 150 | return 0; |
| 151 | } |
| 152 | |
| 153 | static struct freq_attr *loongson2_table_attr[] = { |
| 154 | &cpufreq_freq_attr_scaling_available_freqs, |
| 155 | NULL, |
| 156 | }; |
| 157 | |
| 158 | static struct cpufreq_driver loongson2_cpufreq_driver = { |
| 159 | .owner = THIS_MODULE, |
| 160 | .name = "loongson2", |
| 161 | .init = loongson2_cpufreq_cpu_init, |
| 162 | .verify = loongson2_cpufreq_verify, |
| 163 | .target = loongson2_cpufreq_target, |
| 164 | .get = loongson2_cpufreq_get, |
| 165 | .exit = loongson2_cpufreq_exit, |
| 166 | .attr = loongson2_table_attr, |
| 167 | }; |
| 168 | |
| 169 | static struct platform_device_id platform_device_ids[] = { |
| 170 | { |
| 171 | .name = "loongson2_cpufreq", |
| 172 | }, |
| 173 | {} |
| 174 | }; |
| 175 | |
| 176 | MODULE_DEVICE_TABLE(platform, platform_device_ids); |
| 177 | |
| 178 | static struct platform_driver platform_driver = { |
| 179 | .driver = { |
| 180 | .name = "loongson2_cpufreq", |
| 181 | .owner = THIS_MODULE, |
| 182 | }, |
| 183 | .id_table = platform_device_ids, |
| 184 | }; |
| 185 | |
Ralf Baechle | 95cf146 | 2012-08-01 17:15:32 +0200 | [diff] [blame] | 186 | /* |
| 187 | * This is the simple version of Loongson-2 wait, Maybe we need do this in |
| 188 | * interrupt disabled context. |
| 189 | */ |
| 190 | |
| 191 | static DEFINE_SPINLOCK(loongson2_wait_lock); |
| 192 | |
| 193 | static void loongson2_cpu_wait(void) |
| 194 | { |
| 195 | unsigned long flags; |
| 196 | u32 cpu_freq; |
| 197 | |
| 198 | spin_lock_irqsave(&loongson2_wait_lock, flags); |
| 199 | cpu_freq = LOONGSON_CHIPCFG0; |
Ralf Baechle | 7034228 | 2013-01-22 12:59:30 +0100 | [diff] [blame] | 200 | LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */ |
| 201 | LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */ |
Ralf Baechle | 95cf146 | 2012-08-01 17:15:32 +0200 | [diff] [blame] | 202 | spin_unlock_irqrestore(&loongson2_wait_lock, flags); |
| 203 | } |
| 204 | |
Wu Zhangjin | f8ede0f | 2009-11-17 01:32:59 +0800 | [diff] [blame] | 205 | static int __init cpufreq_init(void) |
| 206 | { |
| 207 | int ret; |
| 208 | |
| 209 | /* Register platform stuff */ |
| 210 | ret = platform_driver_register(&platform_driver); |
| 211 | if (ret) |
| 212 | return ret; |
| 213 | |
| 214 | pr_info("cpufreq: Loongson-2F CPU frequency driver.\n"); |
| 215 | |
| 216 | cpufreq_register_notifier(&loongson2_cpufreq_notifier_block, |
| 217 | CPUFREQ_TRANSITION_NOTIFIER); |
| 218 | |
| 219 | ret = cpufreq_register_driver(&loongson2_cpufreq_driver); |
| 220 | |
| 221 | if (!ret && !nowait) { |
| 222 | saved_cpu_wait = cpu_wait; |
| 223 | cpu_wait = loongson2_cpu_wait; |
| 224 | } |
| 225 | |
| 226 | return ret; |
| 227 | } |
| 228 | |
| 229 | static void __exit cpufreq_exit(void) |
| 230 | { |
| 231 | if (!nowait && saved_cpu_wait) |
| 232 | cpu_wait = saved_cpu_wait; |
| 233 | cpufreq_unregister_driver(&loongson2_cpufreq_driver); |
| 234 | cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block, |
| 235 | CPUFREQ_TRANSITION_NOTIFIER); |
| 236 | |
| 237 | platform_driver_unregister(&platform_driver); |
| 238 | } |
| 239 | |
| 240 | module_init(cpufreq_init); |
| 241 | module_exit(cpufreq_exit); |
| 242 | |
| 243 | module_param(nowait, uint, 0644); |
| 244 | MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); |
| 245 | |
| 246 | MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); |
| 247 | MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); |
| 248 | MODULE_LICENSE("GPL"); |