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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* us3_cpufreq.c: UltraSPARC-III cpu frequency support |
3 | * | |
4 | * Copyright (C) 2003 David S. Miller (davem@redhat.com) | |
5 | * | |
6 | * Many thanks to Dominik Brodowski for fixing up the cpufreq | |
7 | * infrastructure in order to make this driver easier to implement. | |
8 | */ | |
9 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/sched.h> | |
13 | #include <linux/smp.h> | |
14 | #include <linux/cpufreq.h> | |
15 | #include <linux/threads.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/init.h> | |
18 | ||
19 | #include <asm/head.h> | |
20 | #include <asm/timer.h> | |
21 | ||
22 | static struct cpufreq_driver *cpufreq_us3_driver; | |
23 | ||
24 | struct us3_freq_percpu_info { | |
25 | struct cpufreq_frequency_table table[4]; | |
26 | }; | |
27 | ||
28 | /* Indexed by cpu number. */ | |
29 | static struct us3_freq_percpu_info *us3_freq_table; | |
30 | ||
31 | /* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled | |
32 | * in the Safari config register. | |
33 | */ | |
34 | #define SAFARI_CFG_DIV_1 0x0000000000000000UL | |
35 | #define SAFARI_CFG_DIV_2 0x0000000040000000UL | |
36 | #define SAFARI_CFG_DIV_32 0x0000000080000000UL | |
37 | #define SAFARI_CFG_DIV_MASK 0x00000000C0000000UL | |
38 | ||
9fe24c4e | 39 | static void read_safari_cfg(void *arg) |
1da177e4 | 40 | { |
9fe24c4e | 41 | unsigned long ret, *val = arg; |
1da177e4 LT |
42 | |
43 | __asm__ __volatile__("ldxa [%%g0] %1, %0" | |
44 | : "=&r" (ret) | |
45 | : "i" (ASI_SAFARI_CONFIG)); | |
9fe24c4e | 46 | *val = ret; |
1da177e4 LT |
47 | } |
48 | ||
9fe24c4e | 49 | static void update_safari_cfg(void *arg) |
1da177e4 | 50 | { |
9fe24c4e TG |
51 | unsigned long reg, *new_bits = arg; |
52 | ||
53 | read_safari_cfg(®); | |
54 | reg &= ~SAFARI_CFG_DIV_MASK; | |
55 | reg |= *new_bits; | |
56 | ||
1da177e4 LT |
57 | __asm__ __volatile__("stxa %0, [%%g0] %1\n\t" |
58 | "membar #Sync" | |
59 | : /* no outputs */ | |
9fe24c4e | 60 | : "r" (reg), "i" (ASI_SAFARI_CONFIG) |
1da177e4 LT |
61 | : "memory"); |
62 | } | |
63 | ||
64 | static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg) | |
65 | { | |
2cab224d | 66 | unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
67 | unsigned long ret; |
68 | ||
69 | switch (safari_cfg & SAFARI_CFG_DIV_MASK) { | |
70 | case SAFARI_CFG_DIV_1: | |
71 | ret = clock_tick / 1; | |
72 | break; | |
73 | case SAFARI_CFG_DIV_2: | |
74 | ret = clock_tick / 2; | |
75 | break; | |
76 | case SAFARI_CFG_DIV_32: | |
77 | ret = clock_tick / 32; | |
78 | break; | |
79 | default: | |
80 | BUG(); | |
6cb79b3f | 81 | } |
1da177e4 LT |
82 | |
83 | return ret; | |
84 | } | |
85 | ||
2cab224d DM |
86 | static unsigned int us3_freq_get(unsigned int cpu) |
87 | { | |
2cab224d | 88 | unsigned long reg; |
2cab224d | 89 | |
9fe24c4e TG |
90 | if (smp_call_function_single(cpu, read_safari_cfg, ®, 1)) |
91 | return 0; | |
92 | return get_current_freq(cpu, reg); | |
2cab224d DM |
93 | } |
94 | ||
9c0ebcf7 | 95 | static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index) |
1da177e4 | 96 | { |
b43a7ffb | 97 | unsigned int cpu = policy->cpu; |
9fe24c4e | 98 | unsigned long new_bits, new_freq; |
1da177e4 | 99 | |
2cab224d | 100 | new_freq = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
101 | switch (index) { |
102 | case 0: | |
103 | new_bits = SAFARI_CFG_DIV_1; | |
104 | new_freq /= 1; | |
105 | break; | |
106 | case 1: | |
107 | new_bits = SAFARI_CFG_DIV_2; | |
108 | new_freq /= 2; | |
109 | break; | |
110 | case 2: | |
111 | new_bits = SAFARI_CFG_DIV_32; | |
112 | new_freq /= 32; | |
113 | break; | |
114 | ||
115 | default: | |
116 | BUG(); | |
6cb79b3f | 117 | } |
1da177e4 | 118 | |
9fe24c4e | 119 | return smp_call_function_single(cpu, update_safari_cfg, &new_bits, 1); |
1da177e4 LT |
120 | } |
121 | ||
1da177e4 LT |
122 | static int __init us3_freq_cpu_init(struct cpufreq_policy *policy) |
123 | { | |
124 | unsigned int cpu = policy->cpu; | |
2cab224d | 125 | unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
126 | struct cpufreq_frequency_table *table = |
127 | &us3_freq_table[cpu].table[0]; | |
128 | ||
50701588 | 129 | table[0].driver_data = 0; |
1da177e4 | 130 | table[0].frequency = clock_tick / 1; |
50701588 | 131 | table[1].driver_data = 1; |
1da177e4 | 132 | table[1].frequency = clock_tick / 2; |
50701588 | 133 | table[2].driver_data = 2; |
1da177e4 | 134 | table[2].frequency = clock_tick / 32; |
50701588 | 135 | table[3].driver_data = 0; |
1da177e4 LT |
136 | table[3].frequency = CPUFREQ_TABLE_END; |
137 | ||
1da177e4 LT |
138 | policy->cpuinfo.transition_latency = 0; |
139 | policy->cur = clock_tick; | |
31f4b7a8 | 140 | policy->freq_table = table; |
1da177e4 | 141 | |
31f4b7a8 | 142 | return 0; |
1da177e4 LT |
143 | } |
144 | ||
145 | static int us3_freq_cpu_exit(struct cpufreq_policy *policy) | |
146 | { | |
e0b3165b | 147 | if (cpufreq_us3_driver) |
9c0ebcf7 | 148 | us3_freq_target(policy, 0); |
1da177e4 LT |
149 | |
150 | return 0; | |
151 | } | |
152 | ||
153 | static int __init us3_freq_init(void) | |
154 | { | |
155 | unsigned long manuf, impl, ver; | |
156 | int ret; | |
157 | ||
d82ace7d DM |
158 | if (tlb_type != cheetah && tlb_type != cheetah_plus) |
159 | return -ENODEV; | |
160 | ||
1da177e4 LT |
161 | __asm__("rdpr %%ver, %0" : "=r" (ver)); |
162 | manuf = ((ver >> 48) & 0xffff); | |
163 | impl = ((ver >> 32) & 0xffff); | |
164 | ||
165 | if (manuf == CHEETAH_MANUF && | |
d2212bc7 DM |
166 | (impl == CHEETAH_IMPL || |
167 | impl == CHEETAH_PLUS_IMPL || | |
168 | impl == JAGUAR_IMPL || | |
169 | impl == PANTHER_IMPL)) { | |
1da177e4 LT |
170 | struct cpufreq_driver *driver; |
171 | ||
172 | ret = -ENOMEM; | |
d5b73cd8 | 173 | driver = kzalloc(sizeof(*driver), GFP_KERNEL); |
1da177e4 LT |
174 | if (!driver) |
175 | goto err_out; | |
1da177e4 | 176 | |
d5b73cd8 | 177 | us3_freq_table = kzalloc((NR_CPUS * sizeof(*us3_freq_table)), |
1da177e4 LT |
178 | GFP_KERNEL); |
179 | if (!us3_freq_table) | |
180 | goto err_out; | |
181 | ||
2cab224d | 182 | driver->init = us3_freq_cpu_init; |
7a1874a0 | 183 | driver->verify = cpufreq_generic_frequency_table_verify; |
9c0ebcf7 | 184 | driver->target_index = us3_freq_target; |
2cab224d | 185 | driver->get = us3_freq_get; |
1da177e4 | 186 | driver->exit = us3_freq_cpu_exit; |
1da177e4 LT |
187 | strcpy(driver->name, "UltraSPARC-III"); |
188 | ||
189 | cpufreq_us3_driver = driver; | |
190 | ret = cpufreq_register_driver(driver); | |
191 | if (ret) | |
192 | goto err_out; | |
193 | ||
194 | return 0; | |
195 | ||
196 | err_out: | |
197 | if (driver) { | |
198 | kfree(driver); | |
199 | cpufreq_us3_driver = NULL; | |
200 | } | |
b2325fe1 JJ |
201 | kfree(us3_freq_table); |
202 | us3_freq_table = NULL; | |
1da177e4 LT |
203 | return ret; |
204 | } | |
205 | ||
206 | return -ENODEV; | |
207 | } | |
208 | ||
209 | static void __exit us3_freq_exit(void) | |
210 | { | |
211 | if (cpufreq_us3_driver) { | |
212 | cpufreq_unregister_driver(cpufreq_us3_driver); | |
1da177e4 LT |
213 | kfree(cpufreq_us3_driver); |
214 | cpufreq_us3_driver = NULL; | |
215 | kfree(us3_freq_table); | |
216 | us3_freq_table = NULL; | |
217 | } | |
218 | } | |
219 | ||
220 | MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); | |
221 | MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III"); | |
222 | MODULE_LICENSE("GPL"); | |
223 | ||
224 | module_init(us3_freq_init); | |
225 | module_exit(us3_freq_exit); |