diff options
Diffstat (limited to 'arch/sh/kernel/cpufreq.c')
| -rw-r--r-- | arch/sh/kernel/cpufreq.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpufreq.c b/arch/sh/kernel/cpufreq.c new file mode 100644 index 00000000..0fffacea --- /dev/null +++ b/arch/sh/kernel/cpufreq.c @@ -0,0 +1,158 @@ +/* + * arch/sh/kernel/cpufreq.c + * + * cpufreq driver for the SuperH processors. + * + * Copyright (C) 2002 - 2007 Paul Mundt + * Copyright (C) 2002 M. R. Brown + * + * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c + * + * Copyright (C) 2004-2007 Atmel Corporation + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/types.h> +#include <linux/cpufreq.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/cpumask.h> +#include <linux/smp.h> +#include <linux/sched.h> /* set_cpus_allowed() */ +#include <linux/clk.h> + +static struct clk *cpuclk; + +static unsigned int sh_cpufreq_get(unsigned int cpu) +{ + return (clk_get_rate(cpuclk) + 500) / 1000; +} + +/* + * Here we notify other drivers of the proposed change and the final change. + */ +static int sh_cpufreq_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + unsigned int cpu = policy->cpu; + cpumask_t cpus_allowed; + struct cpufreq_freqs freqs; + long freq; + + if (!cpu_online(cpu)) + return -ENODEV; + + cpus_allowed = current->cpus_allowed; + set_cpus_allowed_ptr(current, cpumask_of(cpu)); + + BUG_ON(smp_processor_id() != cpu); + + /* Convert target_freq from kHz to Hz */ + freq = clk_round_rate(cpuclk, target_freq * 1000); + + if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) + return -EINVAL; + + pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); + + freqs.cpu = cpu; + freqs.old = sh_cpufreq_get(cpu); + freqs.new = (freq + 500) / 1000; + freqs.flags = 0; + + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + set_cpus_allowed_ptr(current, &cpus_allowed); + clk_set_rate(cpuclk, freq); + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + pr_debug("cpufreq: set frequency %lu Hz\n", freq); + + return 0; +} + +static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy) +{ + if (!cpu_online(policy->cpu)) + return -ENODEV; + + cpuclk = clk_get(NULL, "cpu_clk"); + if (IS_ERR(cpuclk)) { + printk(KERN_ERR "cpufreq: couldn't get CPU#%d clk\n", + policy->cpu); + return PTR_ERR(cpuclk); + } + + /* cpuinfo and default policy values */ + policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000; + policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; + policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + + policy->cur = sh_cpufreq_get(policy->cpu); + policy->min = policy->cpuinfo.min_freq; + policy->max = policy->cpuinfo.max_freq; + + /* + * Catch the cases where the clock framework hasn't been wired up + * properly to support scaling. + */ + if (unlikely(policy->min == policy->max)) { + printk(KERN_ERR "cpufreq: clock framework rate rounding " + "not supported on CPU#%d.\n", policy->cpu); + + clk_put(cpuclk); + return -EINVAL; + } + + printk(KERN_INFO "cpufreq: CPU#%d Frequencies - Minimum %u.%03u MHz, " + "Maximum %u.%03u MHz.\n", + policy->cpu, policy->min / 1000, policy->min % 1000, + policy->max / 1000, policy->max % 1000); + + return 0; +} + +static int sh_cpufreq_verify(struct cpufreq_policy *policy) +{ + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, + policy->cpuinfo.max_freq); + return 0; +} + +static int sh_cpufreq_exit(struct cpufreq_policy *policy) +{ + clk_put(cpuclk); + return 0; +} + +static struct cpufreq_driver sh_cpufreq_driver = { + .owner = THIS_MODULE, + .name = "sh", + .init = sh_cpufreq_cpu_init, + .verify = sh_cpufreq_verify, + .target = sh_cpufreq_target, + .get = sh_cpufreq_get, + .exit = sh_cpufreq_exit, +}; + +static int __init sh_cpufreq_module_init(void) +{ + printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n"); + return cpufreq_register_driver(&sh_cpufreq_driver); +} + +static void __exit sh_cpufreq_module_exit(void) +{ + cpufreq_unregister_driver(&sh_cpufreq_driver); +} + +module_init(sh_cpufreq_module_init); +module_exit(sh_cpufreq_module_exit); + +MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); +MODULE_DESCRIPTION("cpufreq driver for SuperH"); +MODULE_LICENSE("GPL"); |