diff options
Diffstat (limited to 'arch/arm/mach-omap1/omap1-cpufreq.c')
| -rw-r--r-- | arch/arm/mach-omap1/omap1-cpufreq.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/omap1-cpufreq.c b/arch/arm/mach-omap1/omap1-cpufreq.c new file mode 100644 index 0000000..7c5216e --- /dev/null +++ b/arch/arm/mach-omap1/omap1-cpufreq.c @@ -0,0 +1,175 @@ +/* + * OMAP1 cpufreq driver + * + * CPU frequency scaling for OMAP + * + * Copyright (C) 2005 Nokia Corporation + * Written by Tony Lindgren <tony@atomide.com> + * + * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King + * + * Copyright (C) 2007-2008 Texas Instruments, Inc. + * Rajendra Nayak <rnayak@ti.com> + * + * 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/types.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/cpufreq.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/opp.h> + +#include <asm/system.h> + +#include <plat/clock.h> +#include <plat/omap-pm.h> + +#include <mach/hardware.h> + +#define VERY_HI_RATE 900000000 + +static struct cpufreq_frequency_table *freq_table; +static struct clk *mpu_clk; + +static int omap_verify_speed(struct cpufreq_policy *policy) +{ + if (freq_table) + return cpufreq_frequency_table_verify(policy, freq_table); + + if (policy->cpu) + return -EINVAL; + + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, + policy->cpuinfo.max_freq); + + policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000; + policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000; + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, + policy->cpuinfo.max_freq); + return 0; +} + +static unsigned int omap_getspeed(unsigned int cpu) +{ + unsigned long rate; + + if (cpu) + return 0; + + rate = clk_get_rate(mpu_clk) / 1000; + return rate; +} + +static int omap_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_freqs freqs; + int ret = 0; + + /* Ensure desired rate is within allowed range. Some govenors + * (ondemand) will just pass target_freq=0 to get the minimum. */ + if (target_freq < policy->min) + target_freq = policy->min; + if (target_freq > policy->max) + target_freq = policy->max; + + freqs.old = omap_getspeed(0); + freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; + freqs.cpu = 0; + + if (freqs.old == freqs.new) + return ret; + + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + +#ifdef CONFIG_CPU_FREQ_DEBUG + pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new); +#endif + ret = clk_set_rate(mpu_clk, freqs.new * 1000); + + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + return ret; +} + +static int __init omap_cpu_init(struct cpufreq_policy *policy) +{ + int result = 0; + + mpu_clk = clk_get(NULL, "mpu"); + if (IS_ERR(mpu_clk)) + return PTR_ERR(mpu_clk); + + if (policy->cpu != 0) + return -EINVAL; + + policy->cur = policy->min = policy->max = omap_getspeed(0); + + clk_init_cpufreq_table(&freq_table); + + if (freq_table) { + result = cpufreq_frequency_table_cpuinfo(policy, freq_table); + if (!result) + cpufreq_frequency_table_get_attr(freq_table, + policy->cpu); + } else { + policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000; + policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, + VERY_HI_RATE) / 1000; + } + + policy->min = policy->cpuinfo.min_freq; + policy->max = policy->cpuinfo.max_freq; + policy->cur = omap_getspeed(0); + + /* FIXME: what's the actual transition time? */ + policy->cpuinfo.transition_latency = 300 * 1000; + + return 0; +} + +static int omap_cpu_exit(struct cpufreq_policy *policy) +{ + clk_exit_cpufreq_table(&freq_table); + clk_put(mpu_clk); + return 0; +} + +static struct freq_attr *omap_cpufreq_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, +}; + +static struct cpufreq_driver omap_driver = { + .flags = CPUFREQ_STICKY, + .verify = omap_verify_speed, + .target = omap_target, + .get = omap_getspeed, + .init = omap_cpu_init, + .exit = omap_cpu_exit, + .name = "omap1", + .attr = omap_cpufreq_attr, +}; + +static int __init omap_cpufreq_init(void) +{ + return cpufreq_register_driver(&omap_driver); +} + +static void __exit omap_cpufreq_exit(void) +{ + cpufreq_unregister_driver(&omap_driver); +} + +MODULE_DESCRIPTION("cpufreq driver for OMAP1 SOCs"); +MODULE_LICENSE("GPL"); +module_init(omap_cpufreq_init); +module_exit(omap_cpufreq_exit); |