2 * arch/arm/mach-tegra/cpu-tegra.c
4 * Copyright (C) 2010 Google, Inc.
7 * Colin Cross <ccross@google.com>
8 * Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
10 * This software is licensed under the terms of the GNU General Public
11 * License version 2, as published by the Free Software Foundation, and
12 * may be copied, distributed, and modified under those terms.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/sched.h>
25 #include <linux/cpufreq.h>
26 #include <linux/delay.h>
27 #include <linux/init.h>
28 #include <linux/err.h>
29 #include <linux/clk.h>
31 #include <linux/suspend.h>
33 /* Frequency table index must be sequential starting at 0 */
34 static struct cpufreq_frequency_table freq_table
[] = {
43 { 8, CPUFREQ_TABLE_END
},
48 static struct clk
*cpu_clk
;
49 static struct clk
*pll_x_clk
;
50 static struct clk
*pll_p_clk
;
51 static struct clk
*emc_clk
;
53 static unsigned long target_cpu_speed
[NUM_CPUS
];
54 static DEFINE_MUTEX(tegra_cpu_lock
);
55 static bool is_suspended
;
57 static int tegra_verify_speed(struct cpufreq_policy
*policy
)
59 return cpufreq_frequency_table_verify(policy
, freq_table
);
62 static unsigned int tegra_getspeed(unsigned int cpu
)
69 rate
= clk_get_rate(cpu_clk
) / 1000;
73 static int tegra_cpu_clk_set_rate(unsigned long rate
)
78 * Take an extra reference to the main pll so it doesn't turn
79 * off when we move the cpu off of it
81 clk_prepare_enable(pll_x_clk
);
83 ret
= clk_set_parent(cpu_clk
, pll_p_clk
);
85 pr_err("Failed to switch cpu to clock pll_p\n");
89 if (rate
== clk_get_rate(pll_p_clk
))
92 ret
= clk_set_rate(pll_x_clk
, rate
);
94 pr_err("Failed to change pll_x to %lu\n", rate
);
98 ret
= clk_set_parent(cpu_clk
, pll_x_clk
);
100 pr_err("Failed to switch cpu to clock pll_x\n");
105 clk_disable_unprepare(pll_x_clk
);
109 static int tegra_update_cpu_speed(unsigned long rate
)
112 struct cpufreq_freqs freqs
;
114 freqs
.old
= tegra_getspeed(0);
117 if (freqs
.old
== freqs
.new)
121 * Vote on memory bus frequency based on cpu frequency
122 * This sets the minimum frequency, display or avp may request higher
125 clk_set_rate(emc_clk
, 600000000); /* cpu 816 MHz, emc max */
126 else if (rate
>= 456000)
127 clk_set_rate(emc_clk
, 300000000); /* cpu 456 MHz, emc 150Mhz */
129 clk_set_rate(emc_clk
, 100000000); /* emc 50Mhz */
131 for_each_online_cpu(freqs
.cpu
)
132 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
134 #ifdef CONFIG_CPU_FREQ_DEBUG
135 printk(KERN_DEBUG
"cpufreq-tegra: transition: %u --> %u\n",
136 freqs
.old
, freqs
.new);
139 ret
= tegra_cpu_clk_set_rate(freqs
.new * 1000);
141 pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
146 for_each_online_cpu(freqs
.cpu
)
147 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
152 static unsigned long tegra_cpu_highest_speed(void)
154 unsigned long rate
= 0;
157 for_each_online_cpu(i
)
158 rate
= max(rate
, target_cpu_speed
[i
]);
162 static int tegra_target(struct cpufreq_policy
*policy
,
163 unsigned int target_freq
,
164 unsigned int relation
)
170 mutex_lock(&tegra_cpu_lock
);
177 cpufreq_frequency_table_target(policy
, freq_table
, target_freq
,
180 freq
= freq_table
[idx
].frequency
;
182 target_cpu_speed
[policy
->cpu
] = freq
;
184 ret
= tegra_update_cpu_speed(tegra_cpu_highest_speed());
187 mutex_unlock(&tegra_cpu_lock
);
191 static int tegra_pm_notify(struct notifier_block
*nb
, unsigned long event
,
194 mutex_lock(&tegra_cpu_lock
);
195 if (event
== PM_SUSPEND_PREPARE
) {
197 pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
198 freq_table
[0].frequency
);
199 tegra_update_cpu_speed(freq_table
[0].frequency
);
200 } else if (event
== PM_POST_SUSPEND
) {
201 is_suspended
= false;
203 mutex_unlock(&tegra_cpu_lock
);
208 static struct notifier_block tegra_cpu_pm_notifier
= {
209 .notifier_call
= tegra_pm_notify
,
212 static int tegra_cpu_init(struct cpufreq_policy
*policy
)
214 if (policy
->cpu
>= NUM_CPUS
)
217 cpu_clk
= clk_get_sys(NULL
, "cpu");
219 return PTR_ERR(cpu_clk
);
221 pll_x_clk
= clk_get_sys(NULL
, "pll_x");
222 if (IS_ERR(pll_x_clk
))
223 return PTR_ERR(pll_x_clk
);
225 pll_p_clk
= clk_get_sys(NULL
, "pll_p");
226 if (IS_ERR(pll_p_clk
))
227 return PTR_ERR(pll_p_clk
);
229 emc_clk
= clk_get_sys("cpu", "emc");
230 if (IS_ERR(emc_clk
)) {
232 return PTR_ERR(emc_clk
);
235 clk_prepare_enable(emc_clk
);
236 clk_prepare_enable(cpu_clk
);
238 cpufreq_frequency_table_cpuinfo(policy
, freq_table
);
239 cpufreq_frequency_table_get_attr(freq_table
, policy
->cpu
);
240 policy
->cur
= tegra_getspeed(policy
->cpu
);
241 target_cpu_speed
[policy
->cpu
] = policy
->cur
;
243 /* FIXME: what's the actual transition time? */
244 policy
->cpuinfo
.transition_latency
= 300 * 1000;
246 policy
->shared_type
= CPUFREQ_SHARED_TYPE_ALL
;
247 cpumask_copy(policy
->related_cpus
, cpu_possible_mask
);
249 if (policy
->cpu
== 0)
250 register_pm_notifier(&tegra_cpu_pm_notifier
);
255 static int tegra_cpu_exit(struct cpufreq_policy
*policy
)
257 cpufreq_frequency_table_cpuinfo(policy
, freq_table
);
258 clk_disable_unprepare(emc_clk
);
264 static struct freq_attr
*tegra_cpufreq_attr
[] = {
265 &cpufreq_freq_attr_scaling_available_freqs
,
269 static struct cpufreq_driver tegra_cpufreq_driver
= {
270 .verify
= tegra_verify_speed
,
271 .target
= tegra_target
,
272 .get
= tegra_getspeed
,
273 .init
= tegra_cpu_init
,
274 .exit
= tegra_cpu_exit
,
276 .attr
= tegra_cpufreq_attr
,
279 static int __init
tegra_cpufreq_init(void)
281 return cpufreq_register_driver(&tegra_cpufreq_driver
);
284 static void __exit
tegra_cpufreq_exit(void)
286 cpufreq_unregister_driver(&tegra_cpufreq_driver
);
290 MODULE_AUTHOR("Colin Cross <ccross@android.com>");
291 MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
292 MODULE_LICENSE("GPL");
293 module_init(tegra_cpufreq_init
);
294 module_exit(tegra_cpufreq_exit
);