/* * CPU frequency scaling for DaVinci * * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/ * * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows: * * 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. * Updated to support OMAP3 * 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/cpufreq.h> #include <linux/init.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/platform_device.h> #include <linux/export.h> #include <mach/hardware.h> #include <mach/cpufreq.h> #include <mach/common.h> #include "clock.h" struct davinci_cpufreq { struct device *dev; struct clk *armclk; struct clk *asyncclk; unsigned long asyncrate; }; static struct davinci_cpufreq cpufreq; static int davinci_verify_speed(struct cpufreq_policy *policy) { struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; struct cpufreq_frequency_table *freq_table = pdata->freq_table; struct clk *armclk = cpufreq.armclk; 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(armclk, policy->min * 1000) / 1000; policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000; cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, policy->cpuinfo.max_freq); return 0; } static unsigned int davinci_getspeed(unsigned int cpu) { if (cpu) return 0; return clk_get_rate(cpufreq.armclk) / 1000; } static int davinci_target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation) { int ret = 0; unsigned int idx; struct cpufreq_freqs freqs; struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; struct clk *armclk = cpufreq.armclk; /* * Ensure desired rate is within allowed range. Some govenors * (ondemand) will just pass target_freq=0 to get the minimum. */ if (target_freq < policy->cpuinfo.min_freq) target_freq = policy->cpuinfo.min_freq; if (target_freq > policy->cpuinfo.max_freq) target_freq = policy->cpuinfo.max_freq; freqs.old = davinci_getspeed(0); freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000; freqs.cpu = 0; if (freqs.old == freqs.new) return ret; dev_dbg(cpufreq.dev, "transition: %u --> %u\n", freqs.old, freqs.new); ret = cpufreq_frequency_table_target(policy, pdata->freq_table, freqs.new, relation, &idx); if (ret) return -EINVAL; cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); /* if moving to higher frequency, up the voltage beforehand */ if (pdata->set_voltage && freqs.new > freqs.old) { ret = pdata->set_voltage(idx); if (ret) goto out; } ret = clk_set_rate(armclk, idx); if (ret) goto out; if (cpufreq.asyncclk) { ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate); if (ret) goto out; } /* if moving to lower freq, lower the voltage after lowering freq */ if (pdata->set_voltage && freqs.new < freqs.old) pdata->set_voltage(idx); out: cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); return ret; } static int davinci_cpu_init(struct cpufreq_policy *policy) { int result = 0; struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; struct cpufreq_frequency_table *freq_table = pdata->freq_table; if (policy->cpu != 0) return -EINVAL; /* Finish platform specific initialization */ if (pdata->init) { result = pdata->init(); if (result) return result; } policy->cur = policy->min = policy->max = davinci_getspeed(0); 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 = policy->min; policy->cpuinfo.max_freq = policy->max; } policy->min = policy->cpuinfo.min_freq; policy->max = policy->cpuinfo.max_freq; policy->cur = davinci_getspeed(0); /* * Time measurement across the target() function yields ~1500-1800us * time taken with no drivers on notification list. * Setting the latency to 2000 us to accommodate addition of drivers * to pre/post change notification list. */ policy->cpuinfo.transition_latency = 2000 * 1000; return 0; } static int davinci_cpu_exit(struct cpufreq_policy *policy) { cpufreq_frequency_table_put_attr(policy->cpu); return 0; } static struct freq_attr *davinci_cpufreq_attr[] = { &cpufreq_freq_attr_scaling_available_freqs, NULL, }; static struct cpufreq_driver davinci_driver = { .flags = CPUFREQ_STICKY, .verify = davinci_verify_speed, .target = davinci_target, .get = davinci_getspeed, .init = davinci_cpu_init, .exit = davinci_cpu_exit, .name = "davinci", .attr = davinci_cpufreq_attr, }; static int __init davinci_cpufreq_probe(struct platform_device *pdev) { struct davinci_cpufreq_config *pdata = pdev->dev.platform_data; struct clk *asyncclk; if (!pdata) return -EINVAL; if (!pdata->freq_table) return -EINVAL; cpufreq.dev = &pdev->dev; cpufreq.armclk = clk_get(NULL, "arm"); if (IS_ERR(cpufreq.armclk)) { dev_err(cpufreq.dev, "Unable to get ARM clock\n"); return PTR_ERR(cpufreq.armclk); } asyncclk = clk_get(cpufreq.dev, "async"); if (!IS_ERR(asyncclk)) { cpufreq.asyncclk = asyncclk; cpufreq.asyncrate = clk_get_rate(asyncclk); } return cpufreq_register_driver(&davinci_driver); } static int __exit davinci_cpufreq_remove(struct platform_device *pdev) { clk_put(cpufreq.armclk); if (cpufreq.asyncclk) clk_put(cpufreq.asyncclk); return cpufreq_unregister_driver(&davinci_driver); } static struct platform_driver davinci_cpufreq_driver = { .driver = { .name = "cpufreq-davinci", .owner = THIS_MODULE, }, .remove = __exit_p(davinci_cpufreq_remove), }; int __init davinci_cpufreq_init(void) { return platform_driver_probe(&davinci_cpufreq_driver, davinci_cpufreq_probe); }