1 /*
2  * Versatile Express SPC CPUFreq Interface driver
3  *
4  * It provides necessary ops to arm_big_little cpufreq driver.
5  *
6  * Copyright (C) 2013 ARM Ltd.
7  * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
14  * kind, whether express or implied; without even the implied warranty
15  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  */
18 
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 
21 #include <linux/cpu.h>
22 #include <linux/cpufreq.h>
23 #include <linux/module.h>
24 #include <linux/platform_device.h>
25 #include <linux/pm_opp.h>
26 #include <linux/types.h>
27 
28 #include "arm_big_little.h"
29 
ve_spc_init_opp_table(const struct cpumask * cpumask)30 static int ve_spc_init_opp_table(const struct cpumask *cpumask)
31 {
32 	struct device *cpu_dev = get_cpu_device(cpumask_first(cpumask));
33 	/*
34 	 * platform specific SPC code must initialise the opp table
35 	 * so just check if the OPP count is non-zero
36 	 */
37 	return dev_pm_opp_get_opp_count(cpu_dev) <= 0;
38 }
39 
ve_spc_get_transition_latency(struct device * cpu_dev)40 static int ve_spc_get_transition_latency(struct device *cpu_dev)
41 {
42 	return 1000000; /* 1 ms */
43 }
44 
45 static const struct cpufreq_arm_bL_ops ve_spc_cpufreq_ops = {
46 	.name	= "vexpress-spc",
47 	.get_transition_latency = ve_spc_get_transition_latency,
48 	.init_opp_table = ve_spc_init_opp_table,
49 };
50 
ve_spc_cpufreq_probe(struct platform_device * pdev)51 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
52 {
53 	return bL_cpufreq_register(&ve_spc_cpufreq_ops);
54 }
55 
ve_spc_cpufreq_remove(struct platform_device * pdev)56 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
57 {
58 	bL_cpufreq_unregister(&ve_spc_cpufreq_ops);
59 	return 0;
60 }
61 
62 static struct platform_driver ve_spc_cpufreq_platdrv = {
63 	.driver = {
64 		.name	= "vexpress-spc-cpufreq",
65 	},
66 	.probe		= ve_spc_cpufreq_probe,
67 	.remove		= ve_spc_cpufreq_remove,
68 };
69 module_platform_driver(ve_spc_cpufreq_platdrv);
70 
71 MODULE_LICENSE("GPL");
72