| /* |
| * 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> |
| |
| 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; |
| |
| 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 = davinci_getspeed(0); |
| |
| result = cpufreq_frequency_table_cpuinfo(policy, freq_table); |
| if (result) { |
| pr_err("%s: cpufreq_frequency_table_cpuinfo() failed", |
| __func__); |
| return result; |
| } |
| |
| cpufreq_frequency_table_get_attr(freq_table, policy->cpu); |
| |
| /* |
| * 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); |
| } |
| |