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/* us3_cpufreq.c: UltraSPARC-III cpu frequency support
*
* Copyright (C) 2003 David S. Miller (davem@redhat.com)
*
* Many thanks to Dominik Brodowski for fixing up the cpufreq
* infrastructure in order to make this driver easier to implement.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/cpufreq.h>
#include <linux/threads.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <asm/head.h>
#include <asm/timer.h>
static struct cpufreq_driver *cpufreq_us3_driver;
struct us3_freq_percpu_info {
struct cpufreq_frequency_table table[4];
};
/* Indexed by cpu number. */
static struct us3_freq_percpu_info *us3_freq_table;
/* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled
* in the Safari config register.
*/
#define SAFARI_CFG_DIV_1 0x0000000000000000UL
#define SAFARI_CFG_DIV_2 0x0000000040000000UL
#define SAFARI_CFG_DIV_32 0x0000000080000000UL
#define SAFARI_CFG_DIV_MASK 0x00000000C0000000UL
static unsigned long read_safari_cfg(void)
{
unsigned long ret;
__asm__ __volatile__("ldxa [%%g0] %1, %0"
: "=&r" (ret)
: "i" (ASI_SAFARI_CONFIG));
return ret;
}
static void write_safari_cfg(unsigned long val)
{
__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
"membar #Sync"
: /* no outputs */
: "r" (val), "i" (ASI_SAFARI_CONFIG)
: "memory");
}
static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg)
{
unsigned long clock_tick = sparc64_get_clock_tick(cpu);
unsigned long ret;
switch (safari_cfg & SAFARI_CFG_DIV_MASK) {
case SAFARI_CFG_DIV_1:
ret = clock_tick / 1;
break;
case SAFARI_CFG_DIV_2:
ret = clock_tick / 2;
break;
case SAFARI_CFG_DIV_32:
ret = clock_tick / 32;
break;
default:
BUG();
};
return ret;
}
static void us3_set_cpu_divider_index(unsigned int cpu, unsigned int index)
{
unsigned long new_bits, new_freq, reg;
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
if (!cpu_online(cpu))
return;
cpus_allowed = current->cpus_allowed;
set_cpus_allowed(current, cpumask_of_cpu(cpu));
new_freq = sparc64_get_clock_tick(cpu);
switch (index) {
case 0:
new_bits = SAFARI_CFG_DIV_1;
new_freq /= 1;
break;
case 1:
new_bits = SAFARI_CFG_DIV_2;
new_freq /= 2;
break;
case 2:
new_bits = SAFARI_CFG_DIV_32;
new_freq /= 32;
break;
default:
BUG();
};
reg = read_safari_cfg();
freqs.old = get_current_freq(cpu, reg);
freqs.new = new_freq;
freqs.cpu = cpu;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
reg &= ~SAFARI_CFG_DIV_MASK;
reg |= new_bits;
write_safari_cfg(reg);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
set_cpus_allowed(current, cpus_allowed);
}
static int us3_freq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int new_index = 0;
if (cpufreq_frequency_table_target(policy,
&us3_freq_table[policy->cpu].table[0],
target_freq,
relation,
&new_index))
return -EINVAL;
us3_set_cpu_divider_index(policy->cpu, new_index);
return 0;
}
static int us3_freq_verify(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy,
&us3_freq_table[policy->cpu].table[0]);
}
static int __init us3_freq_cpu_init(struct cpufreq_policy *policy)
{
unsigned int cpu = policy->cpu;
unsigned long clock_tick = sparc64_get_clock_tick(cpu);
struct cpufreq_frequency_table *table =
&us3_freq_table[cpu].table[0];
table[0].index = 0;
table[0].frequency = clock_tick / 1;
table[1].index = 1;
table[1].frequency = clock_tick / 2;
table[2].index = 2;
table[2].frequency = clock_tick / 32;
table[3].index = 0;
table[3].frequency = CPUFREQ_TABLE_END;
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
policy->cpuinfo.transition_latency = 0;
policy->cur = clock_tick;
return cpufreq_frequency_table_cpuinfo(policy, table);
}
static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
{
if (cpufreq_us3_driver)
us3_set_cpu_divider_index(policy->cpu, 0);
return 0;
}
static int __init us3_freq_init(void)
{
unsigned long manuf, impl, ver;
int ret;
__asm__("rdpr %%ver, %0" : "=r" (ver));
manuf = ((ver >> 48) & 0xffff);
impl = ((ver >> 32) & 0xffff);
if (manuf == CHEETAH_MANUF &&
(impl == CHEETAH_IMPL || impl == CHEETAH_PLUS_IMPL)) {
struct cpufreq_driver *driver;
ret = -ENOMEM;
driver = kmalloc(sizeof(struct cpufreq_driver), GFP_KERNEL);
if (!driver)
goto err_out;
memset(driver, 0, sizeof(*driver));
us3_freq_table = kmalloc(
(NR_CPUS * sizeof(struct us3_freq_percpu_info)),
GFP_KERNEL);
if (!us3_freq_table)
goto err_out;
memset(us3_freq_table, 0,
(NR_CPUS * sizeof(struct us3_freq_percpu_info)));
driver->verify = us3_freq_verify;
driver->target = us3_freq_target;
driver->init = us3_freq_cpu_init;
driver->exit = us3_freq_cpu_exit;
driver->owner = THIS_MODULE,
strcpy(driver->name, "UltraSPARC-III");
cpufreq_us3_driver = driver;
ret = cpufreq_register_driver(driver);
if (ret)
goto err_out;
return 0;
err_out:
if (driver) {
kfree(driver);
cpufreq_us3_driver = NULL;
}
if (us3_freq_table) {
kfree(us3_freq_table);
us3_freq_table = NULL;
}
return ret;
}
return -ENODEV;
}
static void __exit us3_freq_exit(void)
{
if (cpufreq_us3_driver) {
cpufreq_unregister_driver(cpufreq_us3_driver);
kfree(cpufreq_us3_driver);
cpufreq_us3_driver = NULL;
kfree(us3_freq_table);
us3_freq_table = NULL;
}
}
MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
MODULE_LICENSE("GPL");
module_init(us3_freq_init);
module_exit(us3_freq_exit);
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