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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sparc64/kernel/us3_cpufreq.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/sparc64/kernel/us3_cpufreq.c')
-rw-r--r--arch/sparc64/kernel/us3_cpufreq.c255
1 files changed, 255 insertions, 0 deletions
diff --git a/arch/sparc64/kernel/us3_cpufreq.c b/arch/sparc64/kernel/us3_cpufreq.c
new file mode 100644
index 000000000000..18fe54b8aa55
--- /dev/null
+++ b/arch/sparc64/kernel/us3_cpufreq.c
@@ -0,0 +1,255 @@
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
21static struct cpufreq_driver *cpufreq_us3_driver;
22
23struct us3_freq_percpu_info {
24 struct cpufreq_frequency_table table[4];
25};
26
27/* Indexed by cpu number. */
28static 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
38static 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
48static 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
57static 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
79static 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
126static 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
144static 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
150static 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
173static 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
181static 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
223err_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
238static 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
250MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
251MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
252MODULE_LICENSE("GPL");
253
254module_init(us3_freq_init);
255module_exit(us3_freq_exit);