Merge branch 'master'
[linux-2.6] / arch / sparc64 / kernel / us3_cpufreq.c
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) / 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
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         cpus_allowed = current->cpus_allowed;
89         set_cpus_allowed(current, cpumask_of_cpu(cpu));
90
91         reg = read_safari_cfg();
92         ret = get_current_freq(cpu, reg);
93
94         set_cpus_allowed(current, cpus_allowed);
95
96         return ret;
97 }
98
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         cpus_allowed = current->cpus_allowed;
109         set_cpus_allowed(current, cpumask_of_cpu(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(current, cpus_allowed);
144 }
145
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
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
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->governor = CPUFREQ_DEFAULT_GOVERNOR;
187         policy->cpuinfo.transition_latency = 0;
188         policy->cur = clock_tick;
189
190         return cpufreq_frequency_table_cpuinfo(policy, table);
191 }
192
193 static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
194 {
195         if (cpufreq_us3_driver)
196                 us3_set_cpu_divider_index(policy->cpu, 0);
197
198         return 0;
199 }
200
201 static int __init us3_freq_init(void)
202 {
203         unsigned long manuf, impl, ver;
204         int ret;
205
206         __asm__("rdpr %%ver, %0" : "=r" (ver));
207         manuf = ((ver >> 48) & 0xffff);
208         impl  = ((ver >> 32) & 0xffff);
209
210         if (manuf == CHEETAH_MANUF &&
211             (impl == CHEETAH_IMPL ||
212              impl == CHEETAH_PLUS_IMPL ||
213              impl == JAGUAR_IMPL ||
214              impl == PANTHER_IMPL)) {
215                 struct cpufreq_driver *driver;
216
217                 ret = -ENOMEM;
218                 driver = kmalloc(sizeof(struct cpufreq_driver), GFP_KERNEL);
219                 if (!driver)
220                         goto err_out;
221                 memset(driver, 0, sizeof(*driver));
222
223                 us3_freq_table = kmalloc(
224                         (NR_CPUS * sizeof(struct us3_freq_percpu_info)),
225                         GFP_KERNEL);
226                 if (!us3_freq_table)
227                         goto err_out;
228
229                 memset(us3_freq_table, 0,
230                        (NR_CPUS * sizeof(struct us3_freq_percpu_info)));
231
232                 driver->init = us3_freq_cpu_init;
233                 driver->verify = us3_freq_verify;
234                 driver->target = us3_freq_target;
235                 driver->get = us3_freq_get;
236                 driver->exit = us3_freq_cpu_exit;
237                 driver->owner = THIS_MODULE,
238                 strcpy(driver->name, "UltraSPARC-III");
239
240                 cpufreq_us3_driver = driver;
241                 ret = cpufreq_register_driver(driver);
242                 if (ret)
243                         goto err_out;
244
245                 return 0;
246
247 err_out:
248                 if (driver) {
249                         kfree(driver);
250                         cpufreq_us3_driver = NULL;
251                 }
252                 kfree(us3_freq_table);
253                 us3_freq_table = NULL;
254                 return ret;
255         }
256
257         return -ENODEV;
258 }
259
260 static void __exit us3_freq_exit(void)
261 {
262         if (cpufreq_us3_driver) {
263                 cpufreq_unregister_driver(cpufreq_us3_driver);
264                 kfree(cpufreq_us3_driver);
265                 cpufreq_us3_driver = NULL;
266                 kfree(us3_freq_table);
267                 us3_freq_table = NULL;
268         }
269 }
270
271 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
272 MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
273 MODULE_LICENSE("GPL");
274
275 module_init(us3_freq_init);
276 module_exit(us3_freq_exit);