diff options
Diffstat (limited to 'drivers/cpufreq/unicore2-cpufreq.c')
-rw-r--r-- | drivers/cpufreq/unicore2-cpufreq.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/drivers/cpufreq/unicore2-cpufreq.c b/drivers/cpufreq/unicore2-cpufreq.c new file mode 100644 index 000000000..db62d9844 --- /dev/null +++ b/drivers/cpufreq/unicore2-cpufreq.c @@ -0,0 +1,79 @@ +/* + * clock scaling for the UniCore-II + * + * Code specific to PKUnity SoC and UniCore ISA + * + * Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn> + * Copyright (C) 2001-2010 Guan Xuetao + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/clk.h> +#include <linux/cpufreq.h> + +#include <mach/hardware.h> + +static struct cpufreq_driver ucv2_driver; + +/* make sure that only the "userspace" governor is run + * -- anything else wouldn't make sense on this platform, anyway. + */ +static int ucv2_verify_speed(struct cpufreq_policy *policy) +{ + if (policy->cpu) + return -EINVAL; + + cpufreq_verify_within_cpu_limits(policy); + return 0; +} + +static int ucv2_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_freqs freqs; + int ret; + + freqs.old = policy->cur; + freqs.new = target_freq; + + cpufreq_freq_transition_begin(policy, &freqs); + ret = clk_set_rate(policy->clk, target_freq * 1000); + cpufreq_freq_transition_end(policy, &freqs, ret); + + return ret; +} + +static int __init ucv2_cpu_init(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -EINVAL; + + policy->min = policy->cpuinfo.min_freq = 250000; + policy->max = policy->cpuinfo.max_freq = 1000000; + policy->clk = clk_get(NULL, "MAIN_CLK"); + return PTR_ERR_OR_ZERO(policy->clk); +} + +static struct cpufreq_driver ucv2_driver = { + .flags = CPUFREQ_STICKY | CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, + .verify = ucv2_verify_speed, + .target = ucv2_target, + .get = cpufreq_generic_get, + .init = ucv2_cpu_init, + .name = "UniCore-II", +}; + +static int __init ucv2_cpufreq_init(void) +{ + return cpufreq_register_driver(&ucv2_driver); +} + +arch_initcall(ucv2_cpufreq_init); |