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
read_safari_cfg(void)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
write_safari_cfg(unsigned long val)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
get_current_freq(unsigned int cpu,unsigned long safari_cfg)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) / 1000;
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
us3_freq_get(unsigned int cpu)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
85 if (!cpu_online(cpu))
86 return 0;
87
88 cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
89 set_cpus_allowed_ptr(current, cpumask_of(cpu));
90
91 reg = read_safari_cfg();
92 ret = get_current_freq(cpu, reg);
93
94 set_cpus_allowed_ptr(current, &cpus_allowed);
95
96 return ret;
97 }
98
us3_set_cpu_divider_index(unsigned int cpu,unsigned int index)99 static void us3_set_cpu_divider_index(unsigned int cpu, unsigned int index)
100 {
101 unsigned long new_bits, new_freq, reg;
102 cpumask_t cpus_allowed;
103 struct cpufreq_freqs freqs;
104
105 if (!cpu_online(cpu))
106 return;
107
108 cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
109 set_cpus_allowed_ptr(current, cpumask_of(cpu));
110
111 new_freq = sparc64_get_clock_tick(cpu) / 1000;
112 switch (index) {
113 case 0:
114 new_bits = SAFARI_CFG_DIV_1;
115 new_freq /= 1;
116 break;
117 case 1:
118 new_bits = SAFARI_CFG_DIV_2;
119 new_freq /= 2;
120 break;
121 case 2:
122 new_bits = SAFARI_CFG_DIV_32;
123 new_freq /= 32;
124 break;
125
126 default:
127 BUG();
128 }
129
130 reg = read_safari_cfg();
131
132 freqs.old = get_current_freq(cpu, reg);
133 freqs.new = new_freq;
134 freqs.cpu = cpu;
135 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
136
137 reg &= ~SAFARI_CFG_DIV_MASK;
138 reg |= new_bits;
139 write_safari_cfg(reg);
140
141 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
142
143 set_cpus_allowed_ptr(current, &cpus_allowed);
144 }
145
us3_freq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)146 static int us3_freq_target(struct cpufreq_policy *policy,
147 unsigned int target_freq,
148 unsigned int relation)
149 {
150 unsigned int new_index = 0;
151
152 if (cpufreq_frequency_table_target(policy,
153 &us3_freq_table[policy->cpu].table[0],
154 target_freq,
155 relation,
156 &new_index))
157 return -EINVAL;
158
159 us3_set_cpu_divider_index(policy->cpu, new_index);
160
161 return 0;
162 }
163
us3_freq_verify(struct cpufreq_policy * policy)164 static int us3_freq_verify(struct cpufreq_policy *policy)
165 {
166 return cpufreq_frequency_table_verify(policy,
167 &us3_freq_table[policy->cpu].table[0]);
168 }
169
us3_freq_cpu_init(struct cpufreq_policy * policy)170 static int __init us3_freq_cpu_init(struct cpufreq_policy *policy)
171 {
172 unsigned int cpu = policy->cpu;
173 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
174 struct cpufreq_frequency_table *table =
175 &us3_freq_table[cpu].table[0];
176
177 table[0].index = 0;
178 table[0].frequency = clock_tick / 1;
179 table[1].index = 1;
180 table[1].frequency = clock_tick / 2;
181 table[2].index = 2;
182 table[2].frequency = clock_tick / 32;
183 table[3].index = 0;
184 table[3].frequency = CPUFREQ_TABLE_END;
185
186 policy->cpuinfo.transition_latency = 0;
187 policy->cur = clock_tick;
188
189 return cpufreq_frequency_table_cpuinfo(policy, table);
190 }
191
us3_freq_cpu_exit(struct cpufreq_policy * policy)192 static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
193 {
194 if (cpufreq_us3_driver)
195 us3_set_cpu_divider_index(policy->cpu, 0);
196
197 return 0;
198 }
199
us3_freq_init(void)200 static int __init us3_freq_init(void)
201 {
202 unsigned long manuf, impl, ver;
203 int ret;
204
205 if (tlb_type != cheetah && tlb_type != cheetah_plus)
206 return -ENODEV;
207
208 __asm__("rdpr %%ver, %0" : "=r" (ver));
209 manuf = ((ver >> 48) & 0xffff);
210 impl = ((ver >> 32) & 0xffff);
211
212 if (manuf == CHEETAH_MANUF &&
213 (impl == CHEETAH_IMPL ||
214 impl == CHEETAH_PLUS_IMPL ||
215 impl == JAGUAR_IMPL ||
216 impl == PANTHER_IMPL)) {
217 struct cpufreq_driver *driver;
218
219 ret = -ENOMEM;
220 driver = kzalloc(sizeof(struct cpufreq_driver), GFP_KERNEL);
221 if (!driver)
222 goto err_out;
223
224 us3_freq_table = kzalloc(
225 (NR_CPUS * sizeof(struct us3_freq_percpu_info)),
226 GFP_KERNEL);
227 if (!us3_freq_table)
228 goto err_out;
229
230 driver->init = us3_freq_cpu_init;
231 driver->verify = us3_freq_verify;
232 driver->target = us3_freq_target;
233 driver->get = us3_freq_get;
234 driver->exit = us3_freq_cpu_exit;
235 driver->owner = THIS_MODULE,
236 strcpy(driver->name, "UltraSPARC-III");
237
238 cpufreq_us3_driver = driver;
239 ret = cpufreq_register_driver(driver);
240 if (ret)
241 goto err_out;
242
243 return 0;
244
245 err_out:
246 if (driver) {
247 kfree(driver);
248 cpufreq_us3_driver = NULL;
249 }
250 kfree(us3_freq_table);
251 us3_freq_table = NULL;
252 return ret;
253 }
254
255 return -ENODEV;
256 }
257
us3_freq_exit(void)258 static void __exit us3_freq_exit(void)
259 {
260 if (cpufreq_us3_driver) {
261 cpufreq_unregister_driver(cpufreq_us3_driver);
262 kfree(cpufreq_us3_driver);
263 cpufreq_us3_driver = NULL;
264 kfree(us3_freq_table);
265 us3_freq_table = NULL;
266 }
267 }
268
269 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
270 MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
271 MODULE_LICENSE("GPL");
272
273 module_init(us3_freq_init);
274 module_exit(us3_freq_exit);
275