Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
bf6fc9fd DJ |
2 | /* |
3 | * sc520_freq.c: cpufreq driver for the AMD Elan sc520 | |
4 | * | |
5 | * Copyright (C) 2005 Sean Young <sean@mess.org> | |
6 | * | |
bf6fc9fd DJ |
7 | * Based on elanfreq.c |
8 | * | |
9 | * 2005-03-30: - initial revision | |
10 | */ | |
11 | ||
1c5864e2 JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
bf6fc9fd DJ |
14 | #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> | |
6072ace4 DJ |
20 | #include <linux/timex.h> |
21 | #include <linux/io.h> | |
bf6fc9fd | 22 | |
fa8031ae | 23 | #include <asm/cpu_device_id.h> |
bf6fc9fd | 24 | #include <asm/msr.h> |
bf6fc9fd DJ |
25 | |
26 | #define MMCR_BASE 0xfffef000 /* The default base address */ | |
27 | #define OFFS_CPUCTL 0x2 /* CPU Control Register */ | |
28 | ||
29 | static __u8 __iomem *cpuctl; | |
30 | ||
bf6fc9fd | 31 | static struct cpufreq_frequency_table sc520_freq_table[] = { |
7f4b0461 VK |
32 | {0, 0x01, 100000}, |
33 | {0, 0x02, 133000}, | |
34 | {0, 0, CPUFREQ_TABLE_END}, | |
bf6fc9fd DJ |
35 | }; |
36 | ||
37 | static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu) | |
38 | { | |
39 | u8 clockspeed_reg = *cpuctl; | |
40 | ||
41 | switch (clockspeed_reg & 0x03) { | |
42 | default: | |
1c5864e2 | 43 | pr_err("error: cpuctl register has unexpected value %02x\n", |
b49c22a6 | 44 | clockspeed_reg); |
9ff6774b | 45 | fallthrough; |
bf6fc9fd DJ |
46 | case 0x01: |
47 | return 100000; | |
48 | case 0x02: | |
49 | return 133000; | |
50 | } | |
51 | } | |
52 | ||
9c0ebcf7 | 53 | static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int state) |
bf6fc9fd DJ |
54 | { |
55 | ||
bf6fc9fd DJ |
56 | u8 clockspeed_reg; |
57 | ||
bf6fc9fd DJ |
58 | local_irq_disable(); |
59 | ||
60 | clockspeed_reg = *cpuctl & ~0x03; | |
50701588 | 61 | *cpuctl = clockspeed_reg | sc520_freq_table[state].driver_data; |
bf6fc9fd DJ |
62 | |
63 | local_irq_enable(); | |
64 | ||
bf6fc9fd DJ |
65 | return 0; |
66 | } | |
67 | ||
bf6fc9fd DJ |
68 | /* |
69 | * Module init and exit code | |
70 | */ | |
71 | ||
72 | static int sc520_freq_cpu_init(struct cpufreq_policy *policy) | |
73 | { | |
92cb7612 | 74 | struct cpuinfo_x86 *c = &cpu_data(0); |
bf6fc9fd DJ |
75 | |
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 */ | |
bf6fc9fd | 82 | policy->cpuinfo.transition_latency = 1000000; /* 1ms */ |
f35750c8 | 83 | policy->freq_table = sc520_freq_table; |
bf6fc9fd | 84 | |
f35750c8 | 85 | return 0; |
bf6fc9fd DJ |
86 | } |
87 | ||
88 | ||
221dee28 | 89 | static struct cpufreq_driver sc520_freq_driver = { |
bf6fc9fd | 90 | .get = sc520_freq_get_cpu_frequency, |
a823c4ae | 91 | .verify = cpufreq_generic_frequency_table_verify, |
9c0ebcf7 | 92 | .target_index = sc520_freq_target, |
bf6fc9fd | 93 | .init = sc520_freq_cpu_init, |
bf6fc9fd | 94 | .name = "sc520_freq", |
a823c4ae | 95 | .attr = cpufreq_generic_attr, |
bf6fc9fd DJ |
96 | }; |
97 | ||
fa8031ae | 98 | static const struct x86_cpu_id sc520_ids[] = { |
b11d77fa | 99 | X86_MATCH_VENDOR_FAM_MODEL(AMD, 4, 9, NULL), |
fa8031ae AK |
100 | {} |
101 | }; | |
102 | MODULE_DEVICE_TABLE(x86cpu, sc520_ids); | |
bf6fc9fd DJ |
103 | |
104 | static int __init sc520_freq_init(void) | |
105 | { | |
3e74341c | 106 | int err; |
bf6fc9fd | 107 | |
fa8031ae | 108 | if (!x86_match_cpu(sc520_ids)) |
bf6fc9fd | 109 | return -ENODEV; |
fa8031ae | 110 | |
bf6fc9fd | 111 | cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1); |
6072ace4 | 112 | if (!cpuctl) { |
b49c22a6 | 113 | pr_err("sc520_freq: error: failed to remap memory\n"); |
bf6fc9fd DJ |
114 | return -ENOMEM; |
115 | } | |
116 | ||
3e74341c AL |
117 | err = cpufreq_register_driver(&sc520_freq_driver); |
118 | if (err) | |
119 | iounmap(cpuctl); | |
120 | ||
121 | return err; | |
bf6fc9fd DJ |
122 | } |
123 | ||
124 | ||
125 | static void __exit sc520_freq_exit(void) | |
126 | { | |
127 | cpufreq_unregister_driver(&sc520_freq_driver); | |
128 | iounmap(cpuctl); | |
129 | } | |
130 | ||
131 | ||
132 | MODULE_LICENSE("GPL"); | |
133 | MODULE_AUTHOR("Sean Young <sean@mess.org>"); | |
134 | MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU"); | |
135 | ||
136 | module_init(sc520_freq_init); | |
137 | module_exit(sc520_freq_exit); | |
138 |