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1da177e4 LT |
1 | /* us3_cpufreq.c: UltraSPARC-III cpu frequency support |
2 | * | |
3 | * Copyright (C) 2003 David S. Miller (davem@redhat.com) | |
4 | * | |
5 | * Many thanks to Dominik Brodowski for fixing up the cpufreq | |
6 | * infrastructure in order to make this driver easier to implement. | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/sched.h> | |
12 | #include <linux/smp.h> | |
13 | #include <linux/cpufreq.h> | |
14 | #include <linux/threads.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/init.h> | |
17 | ||
18 | #include <asm/head.h> | |
19 | #include <asm/timer.h> | |
20 | ||
21 | static struct cpufreq_driver *cpufreq_us3_driver; | |
22 | ||
23 | struct us3_freq_percpu_info { | |
24 | struct cpufreq_frequency_table table[4]; | |
25 | }; | |
26 | ||
27 | /* Indexed by cpu number. */ | |
28 | static struct us3_freq_percpu_info *us3_freq_table; | |
29 | ||
30 | /* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled | |
31 | * in the Safari config register. | |
32 | */ | |
33 | #define SAFARI_CFG_DIV_1 0x0000000000000000UL | |
34 | #define SAFARI_CFG_DIV_2 0x0000000040000000UL | |
35 | #define SAFARI_CFG_DIV_32 0x0000000080000000UL | |
36 | #define SAFARI_CFG_DIV_MASK 0x00000000C0000000UL | |
37 | ||
38 | static unsigned long read_safari_cfg(void) | |
39 | { | |
40 | unsigned long ret; | |
41 | ||
42 | __asm__ __volatile__("ldxa [%%g0] %1, %0" | |
43 | : "=&r" (ret) | |
44 | : "i" (ASI_SAFARI_CONFIG)); | |
45 | return ret; | |
46 | } | |
47 | ||
48 | static void write_safari_cfg(unsigned long val) | |
49 | { | |
50 | __asm__ __volatile__("stxa %0, [%%g0] %1\n\t" | |
51 | "membar #Sync" | |
52 | : /* no outputs */ | |
53 | : "r" (val), "i" (ASI_SAFARI_CONFIG) | |
54 | : "memory"); | |
55 | } | |
56 | ||
57 | static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg) | |
58 | { | |
2cab224d | 59 | unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
60 | unsigned long ret; |
61 | ||
62 | switch (safari_cfg & SAFARI_CFG_DIV_MASK) { | |
63 | case SAFARI_CFG_DIV_1: | |
64 | ret = clock_tick / 1; | |
65 | break; | |
66 | case SAFARI_CFG_DIV_2: | |
67 | ret = clock_tick / 2; | |
68 | break; | |
69 | case SAFARI_CFG_DIV_32: | |
70 | ret = clock_tick / 32; | |
71 | break; | |
72 | default: | |
73 | BUG(); | |
6cb79b3f | 74 | } |
1da177e4 LT |
75 | |
76 | return ret; | |
77 | } | |
78 | ||
2cab224d DM |
79 | static unsigned int us3_freq_get(unsigned int cpu) |
80 | { | |
81 | cpumask_t cpus_allowed; | |
82 | unsigned long reg; | |
83 | unsigned int ret; | |
84 | ||
0c98d344 | 85 | cpumask_copy(&cpus_allowed, ¤t->cpus_allowed); |
d2566af8 | 86 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
2cab224d DM |
87 | |
88 | reg = read_safari_cfg(); | |
89 | ret = get_current_freq(cpu, reg); | |
90 | ||
d2566af8 | 91 | set_cpus_allowed_ptr(current, &cpus_allowed); |
2cab224d DM |
92 | |
93 | return ret; | |
94 | } | |
95 | ||
9c0ebcf7 | 96 | static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index) |
1da177e4 | 97 | { |
b43a7ffb | 98 | unsigned int cpu = policy->cpu; |
1da177e4 LT |
99 | unsigned long new_bits, new_freq, reg; |
100 | cpumask_t cpus_allowed; | |
1da177e4 | 101 | |
0c98d344 | 102 | cpumask_copy(&cpus_allowed, ¤t->cpus_allowed); |
d2566af8 | 103 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
1da177e4 | 104 | |
2cab224d | 105 | new_freq = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
106 | switch (index) { |
107 | case 0: | |
108 | new_bits = SAFARI_CFG_DIV_1; | |
109 | new_freq /= 1; | |
110 | break; | |
111 | case 1: | |
112 | new_bits = SAFARI_CFG_DIV_2; | |
113 | new_freq /= 2; | |
114 | break; | |
115 | case 2: | |
116 | new_bits = SAFARI_CFG_DIV_32; | |
117 | new_freq /= 32; | |
118 | break; | |
119 | ||
120 | default: | |
121 | BUG(); | |
6cb79b3f | 122 | } |
1da177e4 LT |
123 | |
124 | reg = read_safari_cfg(); | |
125 | ||
1da177e4 LT |
126 | reg &= ~SAFARI_CFG_DIV_MASK; |
127 | reg |= new_bits; | |
128 | write_safari_cfg(reg); | |
129 | ||
d2566af8 | 130 | set_cpus_allowed_ptr(current, &cpus_allowed); |
1da177e4 LT |
131 | |
132 | return 0; | |
133 | } | |
134 | ||
1da177e4 LT |
135 | static int __init us3_freq_cpu_init(struct cpufreq_policy *policy) |
136 | { | |
137 | unsigned int cpu = policy->cpu; | |
2cab224d | 138 | unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
139 | struct cpufreq_frequency_table *table = |
140 | &us3_freq_table[cpu].table[0]; | |
141 | ||
50701588 | 142 | table[0].driver_data = 0; |
1da177e4 | 143 | table[0].frequency = clock_tick / 1; |
50701588 | 144 | table[1].driver_data = 1; |
1da177e4 | 145 | table[1].frequency = clock_tick / 2; |
50701588 | 146 | table[2].driver_data = 2; |
1da177e4 | 147 | table[2].frequency = clock_tick / 32; |
50701588 | 148 | table[3].driver_data = 0; |
1da177e4 LT |
149 | table[3].frequency = CPUFREQ_TABLE_END; |
150 | ||
1da177e4 LT |
151 | policy->cpuinfo.transition_latency = 0; |
152 | policy->cur = clock_tick; | |
153 | ||
f1a707c0 | 154 | return cpufreq_table_validate_and_show(policy, table); |
1da177e4 LT |
155 | } |
156 | ||
157 | static int us3_freq_cpu_exit(struct cpufreq_policy *policy) | |
158 | { | |
e0b3165b | 159 | if (cpufreq_us3_driver) |
9c0ebcf7 | 160 | us3_freq_target(policy, 0); |
1da177e4 LT |
161 | |
162 | return 0; | |
163 | } | |
164 | ||
165 | static int __init us3_freq_init(void) | |
166 | { | |
167 | unsigned long manuf, impl, ver; | |
168 | int ret; | |
169 | ||
d82ace7d DM |
170 | if (tlb_type != cheetah && tlb_type != cheetah_plus) |
171 | return -ENODEV; | |
172 | ||
1da177e4 LT |
173 | __asm__("rdpr %%ver, %0" : "=r" (ver)); |
174 | manuf = ((ver >> 48) & 0xffff); | |
175 | impl = ((ver >> 32) & 0xffff); | |
176 | ||
177 | if (manuf == CHEETAH_MANUF && | |
d2212bc7 DM |
178 | (impl == CHEETAH_IMPL || |
179 | impl == CHEETAH_PLUS_IMPL || | |
180 | impl == JAGUAR_IMPL || | |
181 | impl == PANTHER_IMPL)) { | |
1da177e4 LT |
182 | struct cpufreq_driver *driver; |
183 | ||
184 | ret = -ENOMEM; | |
d5b73cd8 | 185 | driver = kzalloc(sizeof(*driver), GFP_KERNEL); |
1da177e4 LT |
186 | if (!driver) |
187 | goto err_out; | |
1da177e4 | 188 | |
d5b73cd8 | 189 | us3_freq_table = kzalloc((NR_CPUS * sizeof(*us3_freq_table)), |
1da177e4 LT |
190 | GFP_KERNEL); |
191 | if (!us3_freq_table) | |
192 | goto err_out; | |
193 | ||
2cab224d | 194 | driver->init = us3_freq_cpu_init; |
7a1874a0 | 195 | driver->verify = cpufreq_generic_frequency_table_verify; |
9c0ebcf7 | 196 | driver->target_index = us3_freq_target; |
2cab224d | 197 | driver->get = us3_freq_get; |
1da177e4 | 198 | driver->exit = us3_freq_cpu_exit; |
1da177e4 LT |
199 | strcpy(driver->name, "UltraSPARC-III"); |
200 | ||
201 | cpufreq_us3_driver = driver; | |
202 | ret = cpufreq_register_driver(driver); | |
203 | if (ret) | |
204 | goto err_out; | |
205 | ||
206 | return 0; | |
207 | ||
208 | err_out: | |
209 | if (driver) { | |
210 | kfree(driver); | |
211 | cpufreq_us3_driver = NULL; | |
212 | } | |
b2325fe1 JJ |
213 | kfree(us3_freq_table); |
214 | us3_freq_table = NULL; | |
1da177e4 LT |
215 | return ret; |
216 | } | |
217 | ||
218 | return -ENODEV; | |
219 | } | |
220 | ||
221 | static void __exit us3_freq_exit(void) | |
222 | { | |
223 | if (cpufreq_us3_driver) { | |
224 | cpufreq_unregister_driver(cpufreq_us3_driver); | |
1da177e4 LT |
225 | kfree(cpufreq_us3_driver); |
226 | cpufreq_us3_driver = NULL; | |
227 | kfree(us3_freq_table); | |
228 | us3_freq_table = NULL; | |
229 | } | |
230 | } | |
231 | ||
232 | MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); | |
233 | MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III"); | |
234 | MODULE_LICENSE("GPL"); | |
235 | ||
236 | module_init(us3_freq_init); | |
237 | module_exit(us3_freq_exit); |