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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 | ||
fb1fece5 | 85 | cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current)); |
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 | ||
b43a7ffb VK |
96 | static void us3_set_cpu_divider_index(struct cpufreq_policy *policy, |
97 | unsigned int index) | |
1da177e4 | 98 | { |
b43a7ffb | 99 | unsigned int cpu = policy->cpu; |
1da177e4 LT |
100 | unsigned long new_bits, new_freq, reg; |
101 | cpumask_t cpus_allowed; | |
102 | struct cpufreq_freqs freqs; | |
103 | ||
fb1fece5 | 104 | cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current)); |
d2566af8 | 105 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); |
1da177e4 | 106 | |
2cab224d | 107 | new_freq = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
108 | switch (index) { |
109 | case 0: | |
110 | new_bits = SAFARI_CFG_DIV_1; | |
111 | new_freq /= 1; | |
112 | break; | |
113 | case 1: | |
114 | new_bits = SAFARI_CFG_DIV_2; | |
115 | new_freq /= 2; | |
116 | break; | |
117 | case 2: | |
118 | new_bits = SAFARI_CFG_DIV_32; | |
119 | new_freq /= 32; | |
120 | break; | |
121 | ||
122 | default: | |
123 | BUG(); | |
6cb79b3f | 124 | } |
1da177e4 LT |
125 | |
126 | reg = read_safari_cfg(); | |
127 | ||
128 | freqs.old = get_current_freq(cpu, reg); | |
129 | freqs.new = new_freq; | |
b43a7ffb | 130 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
1da177e4 LT |
131 | |
132 | reg &= ~SAFARI_CFG_DIV_MASK; | |
133 | reg |= new_bits; | |
134 | write_safari_cfg(reg); | |
135 | ||
b43a7ffb | 136 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
1da177e4 | 137 | |
d2566af8 | 138 | set_cpus_allowed_ptr(current, &cpus_allowed); |
1da177e4 LT |
139 | } |
140 | ||
141 | static int us3_freq_target(struct cpufreq_policy *policy, | |
142 | unsigned int target_freq, | |
143 | unsigned int relation) | |
144 | { | |
145 | unsigned int new_index = 0; | |
146 | ||
147 | if (cpufreq_frequency_table_target(policy, | |
148 | &us3_freq_table[policy->cpu].table[0], | |
149 | target_freq, | |
150 | relation, | |
151 | &new_index)) | |
152 | return -EINVAL; | |
153 | ||
b43a7ffb | 154 | us3_set_cpu_divider_index(policy, new_index); |
1da177e4 LT |
155 | |
156 | return 0; | |
157 | } | |
158 | ||
159 | static int us3_freq_verify(struct cpufreq_policy *policy) | |
160 | { | |
161 | return cpufreq_frequency_table_verify(policy, | |
162 | &us3_freq_table[policy->cpu].table[0]); | |
163 | } | |
164 | ||
165 | static int __init us3_freq_cpu_init(struct cpufreq_policy *policy) | |
166 | { | |
167 | unsigned int cpu = policy->cpu; | |
2cab224d | 168 | unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000; |
1da177e4 LT |
169 | struct cpufreq_frequency_table *table = |
170 | &us3_freq_table[cpu].table[0]; | |
171 | ||
172 | table[0].index = 0; | |
173 | table[0].frequency = clock_tick / 1; | |
174 | table[1].index = 1; | |
175 | table[1].frequency = clock_tick / 2; | |
176 | table[2].index = 2; | |
177 | table[2].frequency = clock_tick / 32; | |
178 | table[3].index = 0; | |
179 | table[3].frequency = CPUFREQ_TABLE_END; | |
180 | ||
1da177e4 LT |
181 | policy->cpuinfo.transition_latency = 0; |
182 | policy->cur = clock_tick; | |
183 | ||
184 | return cpufreq_frequency_table_cpuinfo(policy, table); | |
185 | } | |
186 | ||
187 | static int us3_freq_cpu_exit(struct cpufreq_policy *policy) | |
188 | { | |
189 | if (cpufreq_us3_driver) | |
b43a7ffb | 190 | us3_set_cpu_divider_index(policy, 0); |
1da177e4 LT |
191 | |
192 | return 0; | |
193 | } | |
194 | ||
195 | static int __init us3_freq_init(void) | |
196 | { | |
197 | unsigned long manuf, impl, ver; | |
198 | int ret; | |
199 | ||
d82ace7d DM |
200 | if (tlb_type != cheetah && tlb_type != cheetah_plus) |
201 | return -ENODEV; | |
202 | ||
1da177e4 LT |
203 | __asm__("rdpr %%ver, %0" : "=r" (ver)); |
204 | manuf = ((ver >> 48) & 0xffff); | |
205 | impl = ((ver >> 32) & 0xffff); | |
206 | ||
207 | if (manuf == CHEETAH_MANUF && | |
d2212bc7 DM |
208 | (impl == CHEETAH_IMPL || |
209 | impl == CHEETAH_PLUS_IMPL || | |
210 | impl == JAGUAR_IMPL || | |
211 | impl == PANTHER_IMPL)) { | |
1da177e4 LT |
212 | struct cpufreq_driver *driver; |
213 | ||
214 | ret = -ENOMEM; | |
9132983a | 215 | driver = kzalloc(sizeof(struct cpufreq_driver), GFP_KERNEL); |
1da177e4 LT |
216 | if (!driver) |
217 | goto err_out; | |
1da177e4 | 218 | |
9132983a | 219 | us3_freq_table = kzalloc( |
1da177e4 LT |
220 | (NR_CPUS * sizeof(struct us3_freq_percpu_info)), |
221 | GFP_KERNEL); | |
222 | if (!us3_freq_table) | |
223 | goto err_out; | |
224 | ||
2cab224d | 225 | driver->init = us3_freq_cpu_init; |
1da177e4 LT |
226 | driver->verify = us3_freq_verify; |
227 | driver->target = us3_freq_target; | |
2cab224d | 228 | driver->get = us3_freq_get; |
1da177e4 LT |
229 | driver->exit = us3_freq_cpu_exit; |
230 | driver->owner = THIS_MODULE, | |
231 | strcpy(driver->name, "UltraSPARC-III"); | |
232 | ||
233 | cpufreq_us3_driver = driver; | |
234 | ret = cpufreq_register_driver(driver); | |
235 | if (ret) | |
236 | goto err_out; | |
237 | ||
238 | return 0; | |
239 | ||
240 | err_out: | |
241 | if (driver) { | |
242 | kfree(driver); | |
243 | cpufreq_us3_driver = NULL; | |
244 | } | |
b2325fe1 JJ |
245 | kfree(us3_freq_table); |
246 | us3_freq_table = NULL; | |
1da177e4 LT |
247 | return ret; |
248 | } | |
249 | ||
250 | return -ENODEV; | |
251 | } | |
252 | ||
253 | static void __exit us3_freq_exit(void) | |
254 | { | |
255 | if (cpufreq_us3_driver) { | |
256 | cpufreq_unregister_driver(cpufreq_us3_driver); | |
1da177e4 LT |
257 | kfree(cpufreq_us3_driver); |
258 | cpufreq_us3_driver = NULL; | |
259 | kfree(us3_freq_table); | |
260 | us3_freq_table = NULL; | |
261 | } | |
262 | } | |
263 | ||
264 | MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); | |
265 | MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III"); | |
266 | MODULE_LICENSE("GPL"); | |
267 | ||
268 | module_init(us3_freq_init); | |
269 | module_exit(us3_freq_exit); |