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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 | { | |
59 | unsigned long clock_tick = sparc64_get_clock_tick(cpu); | |
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(); | |
74 | }; | |
75 | ||
76 | return ret; | |
77 | } | |
78 | ||
79 | static void us3_set_cpu_divider_index(unsigned int cpu, unsigned int index) | |
80 | { | |
81 | unsigned long new_bits, new_freq, reg; | |
82 | cpumask_t cpus_allowed; | |
83 | struct cpufreq_freqs freqs; | |
84 | ||
85 | if (!cpu_online(cpu)) | |
86 | return; | |
87 | ||
88 | cpus_allowed = current->cpus_allowed; | |
89 | set_cpus_allowed(current, cpumask_of_cpu(cpu)); | |
90 | ||
91 | new_freq = sparc64_get_clock_tick(cpu); | |
92 | switch (index) { | |
93 | case 0: | |
94 | new_bits = SAFARI_CFG_DIV_1; | |
95 | new_freq /= 1; | |
96 | break; | |
97 | case 1: | |
98 | new_bits = SAFARI_CFG_DIV_2; | |
99 | new_freq /= 2; | |
100 | break; | |
101 | case 2: | |
102 | new_bits = SAFARI_CFG_DIV_32; | |
103 | new_freq /= 32; | |
104 | break; | |
105 | ||
106 | default: | |
107 | BUG(); | |
108 | }; | |
109 | ||
110 | reg = read_safari_cfg(); | |
111 | ||
112 | freqs.old = get_current_freq(cpu, reg); | |
113 | freqs.new = new_freq; | |
114 | freqs.cpu = cpu; | |
115 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
116 | ||
117 | reg &= ~SAFARI_CFG_DIV_MASK; | |
118 | reg |= new_bits; | |
119 | write_safari_cfg(reg); | |
120 | ||
121 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
122 | ||
123 | set_cpus_allowed(current, cpus_allowed); | |
124 | } | |
125 | ||
126 | static int us3_freq_target(struct cpufreq_policy *policy, | |
127 | unsigned int target_freq, | |
128 | unsigned int relation) | |
129 | { | |
130 | unsigned int new_index = 0; | |
131 | ||
132 | if (cpufreq_frequency_table_target(policy, | |
133 | &us3_freq_table[policy->cpu].table[0], | |
134 | target_freq, | |
135 | relation, | |
136 | &new_index)) | |
137 | return -EINVAL; | |
138 | ||
139 | us3_set_cpu_divider_index(policy->cpu, new_index); | |
140 | ||
141 | return 0; | |
142 | } | |
143 | ||
144 | static int us3_freq_verify(struct cpufreq_policy *policy) | |
145 | { | |
146 | return cpufreq_frequency_table_verify(policy, | |
147 | &us3_freq_table[policy->cpu].table[0]); | |
148 | } | |
149 | ||
150 | static int __init us3_freq_cpu_init(struct cpufreq_policy *policy) | |
151 | { | |
152 | unsigned int cpu = policy->cpu; | |
153 | unsigned long clock_tick = sparc64_get_clock_tick(cpu); | |
154 | struct cpufreq_frequency_table *table = | |
155 | &us3_freq_table[cpu].table[0]; | |
156 | ||
157 | table[0].index = 0; | |
158 | table[0].frequency = clock_tick / 1; | |
159 | table[1].index = 1; | |
160 | table[1].frequency = clock_tick / 2; | |
161 | table[2].index = 2; | |
162 | table[2].frequency = clock_tick / 32; | |
163 | table[3].index = 0; | |
164 | table[3].frequency = CPUFREQ_TABLE_END; | |
165 | ||
166 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; | |
167 | policy->cpuinfo.transition_latency = 0; | |
168 | policy->cur = clock_tick; | |
169 | ||
170 | return cpufreq_frequency_table_cpuinfo(policy, table); | |
171 | } | |
172 | ||
173 | static int us3_freq_cpu_exit(struct cpufreq_policy *policy) | |
174 | { | |
175 | if (cpufreq_us3_driver) | |
176 | us3_set_cpu_divider_index(policy->cpu, 0); | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
181 | static int __init us3_freq_init(void) | |
182 | { | |
183 | unsigned long manuf, impl, ver; | |
184 | int ret; | |
185 | ||
186 | __asm__("rdpr %%ver, %0" : "=r" (ver)); | |
187 | manuf = ((ver >> 48) & 0xffff); | |
188 | impl = ((ver >> 32) & 0xffff); | |
189 | ||
190 | if (manuf == CHEETAH_MANUF && | |
191 | (impl == CHEETAH_IMPL || impl == CHEETAH_PLUS_IMPL)) { | |
192 | struct cpufreq_driver *driver; | |
193 | ||
194 | ret = -ENOMEM; | |
195 | driver = kmalloc(sizeof(struct cpufreq_driver), GFP_KERNEL); | |
196 | if (!driver) | |
197 | goto err_out; | |
198 | memset(driver, 0, sizeof(*driver)); | |
199 | ||
200 | us3_freq_table = kmalloc( | |
201 | (NR_CPUS * sizeof(struct us3_freq_percpu_info)), | |
202 | GFP_KERNEL); | |
203 | if (!us3_freq_table) | |
204 | goto err_out; | |
205 | ||
206 | memset(us3_freq_table, 0, | |
207 | (NR_CPUS * sizeof(struct us3_freq_percpu_info))); | |
208 | ||
209 | driver->verify = us3_freq_verify; | |
210 | driver->target = us3_freq_target; | |
211 | driver->init = us3_freq_cpu_init; | |
212 | driver->exit = us3_freq_cpu_exit; | |
213 | driver->owner = THIS_MODULE, | |
214 | strcpy(driver->name, "UltraSPARC-III"); | |
215 | ||
216 | cpufreq_us3_driver = driver; | |
217 | ret = cpufreq_register_driver(driver); | |
218 | if (ret) | |
219 | goto err_out; | |
220 | ||
221 | return 0; | |
222 | ||
223 | err_out: | |
224 | if (driver) { | |
225 | kfree(driver); | |
226 | cpufreq_us3_driver = NULL; | |
227 | } | |
228 | if (us3_freq_table) { | |
229 | kfree(us3_freq_table); | |
230 | us3_freq_table = NULL; | |
231 | } | |
232 | return ret; | |
233 | } | |
234 | ||
235 | return -ENODEV; | |
236 | } | |
237 | ||
238 | static void __exit us3_freq_exit(void) | |
239 | { | |
240 | if (cpufreq_us3_driver) { | |
241 | cpufreq_unregister_driver(cpufreq_us3_driver); | |
242 | ||
243 | kfree(cpufreq_us3_driver); | |
244 | cpufreq_us3_driver = NULL; | |
245 | kfree(us3_freq_table); | |
246 | us3_freq_table = NULL; | |
247 | } | |
248 | } | |
249 | ||
250 | MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); | |
251 | MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III"); | |
252 | MODULE_LICENSE("GPL"); | |
253 | ||
254 | module_init(us3_freq_init); | |
255 | module_exit(us3_freq_exit); |