365b6464e2ce20037e27af6023aa330ba6380612
[linux-2.6.git] / arch / sparc / 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->cpuinfo.transition_latency = 0;
187         policy->cur = clock_tick;
188
189         return cpufreq_frequency_table_cpuinfo(policy, table);
190 }
191
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
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
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);