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156 lines
3.8 KiB
156 lines
3.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* CPU frequency scaling for DaVinci |
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* |
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* Copyright (C) 2009 Texas Instruments Incorporated - https://www.ti.com/ |
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* |
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* Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows: |
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* |
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* Copyright (C) 2005 Nokia Corporation |
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* Written by Tony Lindgren <[email protected]> |
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* |
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* Based on cpu-sa1110.c, Copyright (C) 2001 Russell King |
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* |
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* Copyright (C) 2007-2008 Texas Instruments, Inc. |
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* Updated to support OMAP3 |
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* Rajendra Nayak <[email protected]> |
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*/ |
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#include <linux/types.h> |
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#include <linux/cpufreq.h> |
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#include <linux/init.h> |
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#include <linux/err.h> |
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#include <linux/clk.h> |
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#include <linux/platform_data/davinci-cpufreq.h> |
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#include <linux/platform_device.h> |
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#include <linux/export.h> |
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struct davinci_cpufreq { |
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struct device *dev; |
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struct clk *armclk; |
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struct clk *asyncclk; |
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unsigned long asyncrate; |
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}; |
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static struct davinci_cpufreq cpufreq; |
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static int davinci_target(struct cpufreq_policy *policy, unsigned int idx) |
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{ |
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struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; |
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struct clk *armclk = cpufreq.armclk; |
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unsigned int old_freq, new_freq; |
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int ret = 0; |
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old_freq = policy->cur; |
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new_freq = pdata->freq_table[idx].frequency; |
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/* if moving to higher frequency, up the voltage beforehand */ |
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if (pdata->set_voltage && new_freq > old_freq) { |
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ret = pdata->set_voltage(idx); |
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if (ret) |
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return ret; |
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} |
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ret = clk_set_rate(armclk, new_freq * 1000); |
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if (ret) |
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return ret; |
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if (cpufreq.asyncclk) { |
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ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate); |
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if (ret) |
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return ret; |
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} |
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/* if moving to lower freq, lower the voltage after lowering freq */ |
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if (pdata->set_voltage && new_freq < old_freq) |
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pdata->set_voltage(idx); |
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return 0; |
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} |
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static int davinci_cpu_init(struct cpufreq_policy *policy) |
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{ |
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int result = 0; |
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struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; |
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struct cpufreq_frequency_table *freq_table = pdata->freq_table; |
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if (policy->cpu != 0) |
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return -EINVAL; |
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/* Finish platform specific initialization */ |
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if (pdata->init) { |
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result = pdata->init(); |
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if (result) |
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return result; |
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} |
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policy->clk = cpufreq.armclk; |
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/* |
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* Time measurement across the target() function yields ~1500-1800us |
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* time taken with no drivers on notification list. |
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* Setting the latency to 2000 us to accommodate addition of drivers |
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* to pre/post change notification list. |
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*/ |
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cpufreq_generic_init(policy, freq_table, 2000 * 1000); |
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return 0; |
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} |
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static struct cpufreq_driver davinci_driver = { |
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.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, |
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.verify = cpufreq_generic_frequency_table_verify, |
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.target_index = davinci_target, |
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.get = cpufreq_generic_get, |
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.init = davinci_cpu_init, |
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.name = "davinci", |
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.attr = cpufreq_generic_attr, |
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}; |
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static int __init davinci_cpufreq_probe(struct platform_device *pdev) |
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{ |
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struct davinci_cpufreq_config *pdata = pdev->dev.platform_data; |
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struct clk *asyncclk; |
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if (!pdata) |
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return -EINVAL; |
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if (!pdata->freq_table) |
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return -EINVAL; |
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cpufreq.dev = &pdev->dev; |
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cpufreq.armclk = clk_get(NULL, "arm"); |
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if (IS_ERR(cpufreq.armclk)) { |
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dev_err(cpufreq.dev, "Unable to get ARM clock\n"); |
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return PTR_ERR(cpufreq.armclk); |
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} |
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asyncclk = clk_get(cpufreq.dev, "async"); |
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if (!IS_ERR(asyncclk)) { |
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cpufreq.asyncclk = asyncclk; |
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cpufreq.asyncrate = clk_get_rate(asyncclk); |
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} |
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return cpufreq_register_driver(&davinci_driver); |
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} |
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static int __exit davinci_cpufreq_remove(struct platform_device *pdev) |
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{ |
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clk_put(cpufreq.armclk); |
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if (cpufreq.asyncclk) |
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clk_put(cpufreq.asyncclk); |
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return cpufreq_unregister_driver(&davinci_driver); |
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} |
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static struct platform_driver davinci_cpufreq_driver = { |
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.driver = { |
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.name = "cpufreq-davinci", |
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}, |
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.remove = __exit_p(davinci_cpufreq_remove), |
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}; |
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int __init davinci_cpufreq_init(void) |
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{ |
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return platform_driver_probe(&davinci_cpufreq_driver, |
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davinci_cpufreq_probe); |
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} |
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