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Thomas Gleixner2874c5f2019-05-27 08:55:01 +02001// SPDX-License-Identifier: GPL-2.0-or-later
Dave Jonesbf6fc9f2005-05-31 19:03:45 -07002/*
3 * sc520_freq.c: cpufreq driver for the AMD Elan sc520
4 *
5 * Copyright (C) 2005 Sean Young <sean@mess.org>
6 *
Dave Jonesbf6fc9f2005-05-31 19:03:45 -07007 * Based on elanfreq.c
8 *
9 * 2005-03-30: - initial revision
10 */
11
Joe Perches1c5864e2016-04-05 13:28:25 -070012#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070014#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/init.h>
17
18#include <linux/delay.h>
19#include <linux/cpufreq.h>
Dave Jones6072ace2009-01-18 01:27:35 -050020#include <linux/timex.h>
21#include <linux/io.h>
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070022
Andi Kleenfa8031a2012-01-26 00:09:12 +010023#include <asm/cpu_device_id.h>
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070024#include <asm/msr.h>
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070025
26#define MMCR_BASE 0xfffef000 /* The default base address */
27#define OFFS_CPUCTL 0x2 /* CPU Control Register */
28
29static __u8 __iomem *cpuctl;
30
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070031static struct cpufreq_frequency_table sc520_freq_table[] = {
Viresh Kumar7f4b0462014-03-28 19:11:47 +053032 {0, 0x01, 100000},
33 {0, 0x02, 133000},
34 {0, 0, CPUFREQ_TABLE_END},
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070035};
36
37static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu)
38{
39 u8 clockspeed_reg = *cpuctl;
40
41 switch (clockspeed_reg & 0x03) {
42 default:
Joe Perches1c5864e2016-04-05 13:28:25 -070043 pr_err("error: cpuctl register has unexpected value %02x\n",
Joe Perchesb49c22a2016-04-05 13:28:24 -070044 clockspeed_reg);
Randy Dunlap9ff67742021-05-03 09:18:40 -070045 fallthrough;
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070046 case 0x01:
47 return 100000;
48 case 0x02:
49 return 133000;
50 }
51}
52
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053053static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int state)
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070054{
55
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070056 u8 clockspeed_reg;
57
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070058 local_irq_disable();
59
60 clockspeed_reg = *cpuctl & ~0x03;
Viresh Kumar50701582013-03-30 16:25:15 +053061 *cpuctl = clockspeed_reg | sc520_freq_table[state].driver_data;
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070062
63 local_irq_enable();
64
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070065 return 0;
66}
67
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070068/*
69 * Module init and exit code
70 */
71
72static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
73{
Mike Travis92cb7612007-10-19 20:35:04 +020074 struct cpuinfo_x86 *c = &cpu_data(0);
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070075
76 /* capability check */
77 if (c->x86_vendor != X86_VENDOR_AMD ||
78 c->x86 != 4 || c->x86_model != 9)
79 return -ENODEV;
80
81 /* cpuinfo and default policy values */
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070082 policy->cpuinfo.transition_latency = 1000000; /* 1ms */
Viresh Kumarf35750c2018-02-26 10:39:03 +053083 policy->freq_table = sc520_freq_table;
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070084
Viresh Kumarf35750c2018-02-26 10:39:03 +053085 return 0;
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070086}
87
88
Linus Torvalds221dee22007-02-26 14:55:48 -080089static struct cpufreq_driver sc520_freq_driver = {
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070090 .get = sc520_freq_get_cpu_frequency,
Viresh Kumara823c4a2013-10-03 20:28:24 +053091 .verify = cpufreq_generic_frequency_table_verify,
Viresh Kumar9c0ebcf2013-10-25 19:45:48 +053092 .target_index = sc520_freq_target,
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070093 .init = sc520_freq_cpu_init,
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070094 .name = "sc520_freq",
Viresh Kumara823c4a2013-10-03 20:28:24 +053095 .attr = cpufreq_generic_attr,
Dave Jonesbf6fc9f2005-05-31 19:03:45 -070096};
97
Andi Kleenfa8031a2012-01-26 00:09:12 +010098static const struct x86_cpu_id sc520_ids[] = {
Thomas Gleixnerb11d77f2020-03-24 14:51:51 +010099 X86_MATCH_VENDOR_FAM_MODEL(AMD, 4, 9, NULL),
Andi Kleenfa8031a2012-01-26 00:09:12 +0100100 {}
101};
102MODULE_DEVICE_TABLE(x86cpu, sc520_ids);
Dave Jonesbf6fc9f2005-05-31 19:03:45 -0700103
104static int __init sc520_freq_init(void)
105{
Amol Lad3e743412006-10-17 10:02:55 +0530106 int err;
Dave Jonesbf6fc9f2005-05-31 19:03:45 -0700107
Andi Kleenfa8031a2012-01-26 00:09:12 +0100108 if (!x86_match_cpu(sc520_ids))
Dave Jonesbf6fc9f2005-05-31 19:03:45 -0700109 return -ENODEV;
Andi Kleenfa8031a2012-01-26 00:09:12 +0100110
Dave Jonesbf6fc9f2005-05-31 19:03:45 -0700111 cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1);
Dave Jones6072ace2009-01-18 01:27:35 -0500112 if (!cpuctl) {
Joe Perchesb49c22a2016-04-05 13:28:24 -0700113 pr_err("sc520_freq: error: failed to remap memory\n");
Dave Jonesbf6fc9f2005-05-31 19:03:45 -0700114 return -ENOMEM;
115 }
116
Amol Lad3e743412006-10-17 10:02:55 +0530117 err = cpufreq_register_driver(&sc520_freq_driver);
118 if (err)
119 iounmap(cpuctl);
120
121 return err;
Dave Jonesbf6fc9f2005-05-31 19:03:45 -0700122}
123
124
125static void __exit sc520_freq_exit(void)
126{
127 cpufreq_unregister_driver(&sc520_freq_driver);
128 iounmap(cpuctl);
129}
130
131
132MODULE_LICENSE("GPL");
133MODULE_AUTHOR("Sean Young <sean@mess.org>");
134MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU");
135
136module_init(sc520_freq_init);
137module_exit(sc520_freq_exit);
138