1 /* us3_cpufreq.c: UltraSPARC-III cpu frequency support
3 * Copyright (C) 2003 David S. Miller (davem@redhat.com)
5 * Many thanks to Dominik Brodowski for fixing up the cpufreq
6 * infrastructure in order to make this driver easier to implement.
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>
19 #include <asm/timer.h>
21 static struct cpufreq_driver *cpufreq_us3_driver;
23 struct us3_freq_percpu_info {
24 struct cpufreq_frequency_table table[4];
27 /* Indexed by cpu number. */
28 static struct us3_freq_percpu_info *us3_freq_table;
30 /* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled
31 * in the Safari config register.
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
38 static unsigned long read_safari_cfg(void)
42 __asm__ __volatile__("ldxa [%%g0] %1, %0"
44 : "i" (ASI_SAFARI_CONFIG));
48 static void write_safari_cfg(unsigned long val)
50 __asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
53 : "r" (val), "i" (ASI_SAFARI_CONFIG)
57 static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg)
59 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
62 switch (safari_cfg & SAFARI_CFG_DIV_MASK) {
63 case SAFARI_CFG_DIV_1:
66 case SAFARI_CFG_DIV_2:
69 case SAFARI_CFG_DIV_32:
70 ret = clock_tick / 32;
79 static unsigned int us3_freq_get(unsigned int cpu)
81 cpumask_t cpus_allowed;
85 cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
86 set_cpus_allowed_ptr(current, cpumask_of(cpu));
88 reg = read_safari_cfg();
89 ret = get_current_freq(cpu, reg);
91 set_cpus_allowed_ptr(current, &cpus_allowed);
96 static void us3_set_cpu_divider_index(struct cpufreq_policy *policy,
99 unsigned int cpu = policy->cpu;
100 unsigned long new_bits, new_freq, reg;
101 cpumask_t cpus_allowed;
102 struct cpufreq_freqs freqs;
104 cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
105 set_cpus_allowed_ptr(current, cpumask_of(cpu));
107 new_freq = sparc64_get_clock_tick(cpu) / 1000;
110 new_bits = SAFARI_CFG_DIV_1;
114 new_bits = SAFARI_CFG_DIV_2;
118 new_bits = SAFARI_CFG_DIV_32;
126 reg = read_safari_cfg();
128 freqs.old = get_current_freq(cpu, reg);
129 freqs.new = new_freq;
130 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
132 reg &= ~SAFARI_CFG_DIV_MASK;
134 write_safari_cfg(reg);
136 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
138 set_cpus_allowed_ptr(current, &cpus_allowed);
141 static int us3_freq_target(struct cpufreq_policy *policy,
142 unsigned int target_freq,
143 unsigned int relation)
145 unsigned int new_index = 0;
147 if (cpufreq_frequency_table_target(policy,
148 &us3_freq_table[policy->cpu].table[0],
154 us3_set_cpu_divider_index(policy, new_index);
159 static int __init us3_freq_cpu_init(struct cpufreq_policy *policy)
161 unsigned int cpu = policy->cpu;
162 unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
163 struct cpufreq_frequency_table *table =
164 &us3_freq_table[cpu].table[0];
166 table[0].driver_data = 0;
167 table[0].frequency = clock_tick / 1;
168 table[1].driver_data = 1;
169 table[1].frequency = clock_tick / 2;
170 table[2].driver_data = 2;
171 table[2].frequency = clock_tick / 32;
172 table[3].driver_data = 0;
173 table[3].frequency = CPUFREQ_TABLE_END;
175 policy->cpuinfo.transition_latency = 0;
176 policy->cur = clock_tick;
178 return cpufreq_table_validate_and_show(policy, table);
181 static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
183 if (cpufreq_us3_driver) {
184 cpufreq_frequency_table_put_attr(policy->cpu);
185 us3_set_cpu_divider_index(policy, 0);
191 static int __init us3_freq_init(void)
193 unsigned long manuf, impl, ver;
196 if (tlb_type != cheetah && tlb_type != cheetah_plus)
199 __asm__("rdpr %%ver, %0" : "=r" (ver));
200 manuf = ((ver >> 48) & 0xffff);
201 impl = ((ver >> 32) & 0xffff);
203 if (manuf == CHEETAH_MANUF &&
204 (impl == CHEETAH_IMPL ||
205 impl == CHEETAH_PLUS_IMPL ||
206 impl == JAGUAR_IMPL ||
207 impl == PANTHER_IMPL)) {
208 struct cpufreq_driver *driver;
211 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
215 us3_freq_table = kzalloc((NR_CPUS * sizeof(*us3_freq_table)),
220 driver->init = us3_freq_cpu_init;
221 driver->verify = cpufreq_generic_frequency_table_verify;
222 driver->target = us3_freq_target;
223 driver->get = us3_freq_get;
224 driver->exit = us3_freq_cpu_exit;
225 strcpy(driver->name, "UltraSPARC-III");
227 cpufreq_us3_driver = driver;
228 ret = cpufreq_register_driver(driver);
237 cpufreq_us3_driver = NULL;
239 kfree(us3_freq_table);
240 us3_freq_table = NULL;
247 static void __exit us3_freq_exit(void)
249 if (cpufreq_us3_driver) {
250 cpufreq_unregister_driver(cpufreq_us3_driver);
251 kfree(cpufreq_us3_driver);
252 cpufreq_us3_driver = NULL;
253 kfree(us3_freq_table);
254 us3_freq_table = NULL;
258 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
259 MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
260 MODULE_LICENSE("GPL");
262 module_init(us3_freq_init);
263 module_exit(us3_freq_exit);