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Release 4.14 drivers/cpufreq/loongson1-cpufreq.c

Directory: drivers/cpufreq
/*
 * CPU Frequency Scaling for Loongson 1 SoC
 *
 * Copyright (C) 2014-2016 Zhang, Keguang <keguang.zhang@gmail.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <cpufreq.h>
#include <loongson1.h>


struct ls1x_cpufreq {
	
struct device *dev;
	
struct clk *clk;	/* CPU clk */
	
struct clk *mux_clk;	/* MUX of CPU clk */
	
struct clk *pll_clk;	/* PLL clk */
	
struct clk *osc_clk;	/* OSC clk */
	
unsigned int max_freq;
	
unsigned int min_freq;
};


static struct ls1x_cpufreq *cpufreq;


static int ls1x_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data) { if (val == CPUFREQ_POSTCHANGE) current_cpu_data.udelay_val = loops_per_jiffy; return NOTIFY_OK; }

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static struct notifier_block ls1x_cpufreq_notifier_block = { .notifier_call = ls1x_cpufreq_notifier };
static int ls1x_cpufreq_target(struct cpufreq_policy *policy, unsigned int index) { struct device *cpu_dev = get_cpu_device(policy->cpu); unsigned int old_freq, new_freq; old_freq = policy->cur; new_freq = policy->freq_table[index].frequency; /* * The procedure of reconfiguring CPU clk is as below. * * - Reparent CPU clk to OSC clk * - Reset CPU clock (very important) * - Reconfigure CPU DIV * - Reparent CPU clk back to CPU DIV clk */ clk_set_parent(policy->clk, cpufreq->osc_clk); __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) | RST_CPU_EN | RST_CPU, LS1X_CLK_PLL_DIV); __raw_writel(__raw_readl(LS1X_CLK_PLL_DIV) & ~(RST_CPU_EN | RST_CPU), LS1X_CLK_PLL_DIV); clk_set_rate(cpufreq->mux_clk, new_freq * 1000); clk_set_parent(policy->clk, cpufreq->mux_clk); dev_dbg(cpu_dev, "%u KHz --> %u KHz\n", old_freq, new_freq); return 0; }

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static int ls1x_cpufreq_init(struct cpufreq_policy *policy) { struct device *cpu_dev = get_cpu_device(policy->cpu); struct cpufreq_frequency_table *freq_tbl; unsigned int pll_freq, freq; int steps, i, ret; pll_freq = clk_get_rate(cpufreq->pll_clk) / 1000; steps = 1 << DIV_CPU_WIDTH; freq_tbl = kcalloc(steps, sizeof(*freq_tbl), GFP_KERNEL); if (!freq_tbl) return -ENOMEM; for (i = 0; i < (steps - 1); i++) { freq = pll_freq / (i + 1); if ((freq < cpufreq->min_freq) || (freq > cpufreq->max_freq)) freq_tbl[i].frequency = CPUFREQ_ENTRY_INVALID; else freq_tbl[i].frequency = freq; dev_dbg(cpu_dev, "cpufreq table: index %d: frequency %d\n", i, freq_tbl[i].frequency); } freq_tbl[i].frequency = CPUFREQ_TABLE_END; policy->clk = cpufreq->clk; ret = cpufreq_generic_init(policy, freq_tbl, 0); if (ret) kfree(freq_tbl); return ret; }

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static int ls1x_cpufreq_exit(struct cpufreq_policy *policy) { kfree(policy->freq_table); return 0; }

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static struct cpufreq_driver ls1x_cpufreq_driver = { .name = "cpufreq-ls1x", .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, .verify = cpufreq_generic_frequency_table_verify, .target_index = ls1x_cpufreq_target, .get = cpufreq_generic_get, .init = ls1x_cpufreq_init, .exit = ls1x_cpufreq_exit, .attr = cpufreq_generic_attr, };
static int ls1x_cpufreq_remove(struct platform_device *pdev) { cpufreq_unregister_notifier(&ls1x_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); cpufreq_unregister_driver(&ls1x_cpufreq_driver); return 0; }

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static int ls1x_cpufreq_probe(struct platform_device *pdev) { struct plat_ls1x_cpufreq *pdata = dev_get_platdata(&pdev->dev); struct clk *clk; int ret; if (!pdata || !pdata->clk_name || !pdata->osc_clk_name) { dev_err(&pdev->dev, "platform data missing\n"); return -EINVAL; } cpufreq = devm_kzalloc(&pdev->dev, sizeof(struct ls1x_cpufreq), GFP_KERNEL); if (!cpufreq) return -ENOMEM; cpufreq->dev = &pdev->dev; clk = devm_clk_get(&pdev->dev, pdata->clk_name); if (IS_ERR(clk)) { dev_err(&pdev->dev, "unable to get %s clock\n", pdata->clk_name); return PTR_ERR(clk); } cpufreq->clk = clk; clk = clk_get_parent(clk); if (IS_ERR(clk)) { dev_err(&pdev->dev, "unable to get parent of %s clock\n", __clk_get_name(cpufreq->clk)); return PTR_ERR(clk); } cpufreq->mux_clk = clk; clk = clk_get_parent(clk); if (IS_ERR(clk)) { dev_err(&pdev->dev, "unable to get parent of %s clock\n", __clk_get_name(cpufreq->mux_clk)); return PTR_ERR(clk); } cpufreq->pll_clk = clk; clk = devm_clk_get(&pdev->dev, pdata->osc_clk_name); if (IS_ERR(clk)) { dev_err(&pdev->dev, "unable to get %s clock\n", pdata->osc_clk_name); return PTR_ERR(clk); } cpufreq->osc_clk = clk; cpufreq->max_freq = pdata->max_freq; cpufreq->min_freq = pdata->min_freq; ret = cpufreq_register_driver(&ls1x_cpufreq_driver); if (ret) { dev_err(&pdev->dev, "failed to register CPUFreq driver: %d\n", ret); return ret; } ret = cpufreq_register_notifier(&ls1x_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); if (ret) { dev_err(&pdev->dev, "failed to register CPUFreq notifier: %d\n",ret); cpufreq_unregister_driver(&ls1x_cpufreq_driver); } return ret; }

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static struct platform_driver ls1x_cpufreq_platdrv = { .probe = ls1x_cpufreq_probe, .remove = ls1x_cpufreq_remove, .driver = { .name = "ls1x-cpufreq", }, }; module_platform_driver(ls1x_cpufreq_platdrv); MODULE_AUTHOR("Kelvin Cheung <keguang.zhang@gmail.com>"); MODULE_DESCRIPTION("Loongson1 CPUFreq driver"); MODULE_LICENSE("GPL");

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Directory: drivers/cpufreq
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