| /* |
| * linux/arch/arm/plat-omap/cpu-omap.c |
| * |
| * 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 |
| * |
| * 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 <asm/arch/hardware.h> |
| #include <asm/io.h> |
| #include <asm/system.h> |
| |
| #define VERY_HI_RATE 900000000 |
| |
| #ifdef CONFIG_ARCH_OMAP1 |
| #define MPU_CLK "mpu" |
| #else |
| #define MPU_CLK "virt_prcm_set" |
| #endif |
| |
| static struct clk *mpu_clk; |
| |
| /* TODO: Add support for SDRAM timing changes */ |
| |
| int omap_verify_speed(struct cpufreq_policy *policy) |
| { |
| 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; |
| } |
| |
| 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; |
| |
| freqs.old = omap_getspeed(0); |
| freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; |
| freqs.cpu = 0; |
| |
| cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
| ret = clk_set_rate(mpu_clk, target_freq * 1000); |
| cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| |
| return ret; |
| } |
| |
| static int __init omap_cpu_init(struct cpufreq_policy *policy) |
| { |
| mpu_clk = clk_get(NULL, MPU_CLK); |
| 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); |
| 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->cpuinfo.transition_latency = CPUFREQ_ETERNAL; |
| |
| return 0; |
| } |
| |
| static int omap_cpu_exit(struct cpufreq_policy *policy) |
| { |
| clk_put(mpu_clk); |
| return 0; |
| } |
| |
| 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 = "omap", |
| }; |
| |
| static int __init omap_cpufreq_init(void) |
| { |
| return cpufreq_register_driver(&omap_driver); |
| } |
| |
| arch_initcall(omap_cpufreq_init); |