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// SPDX-License-Identifier: GPL-2.0-only
/* 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>
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 void read_safari_cfg(void *arg)
{
unsigned long ret, *val = arg;
__asm__ __volatile__("ldxa [%%g0] %1, %0"
: "=&r" (ret)
: "i" (ASI_SAFARI_CONFIG));
*val = ret;
}
static void update_safari_cfg(void *arg)
{
unsigned long reg, *new_bits = arg;
read_safari_cfg(®);
reg &= ~SAFARI_CFG_DIV_MASK;
reg |= *new_bits;
__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
"membar #Sync"
: /* no outputs */
: "r" (reg), "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) / 1000;
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 unsigned int us3_freq_get(unsigned int cpu)
{
unsigned long reg;
if (smp_call_function_single(cpu, read_safari_cfg, ®, 1))
return 0;
return get_current_freq(cpu, reg);
}
static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index)
{
unsigned int cpu = policy->cpu;
unsigned long new_bits, new_freq;
new_freq = sparc64_get_clock_tick(cpu) / 1000;
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();
}
return smp_call_function_single(cpu, update_safari_cfg, &new_bits, 1);
}
static int us3_freq_cpu_init(struct cpufreq_policy *policy)
{
unsigned int cpu = policy->cpu;
unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
struct cpufreq_frequency_table *table =
&us3_freq_table[cpu].table[0];
table[0].driver_data = 0;
table[0].frequency = clock_tick / 1;
table[1].driver_data = 1;
table[1].frequency = clock_tick / 2;
table[2].driver_data = 2;
table[2].frequency = clock_tick / 32;
table[3].driver_data = 0;
table[3].frequency = CPUFREQ_TABLE_END;
policy->cpuinfo.transition_latency = 0;
policy->cur = clock_tick;
policy->freq_table = table;
return 0;
}
static void us3_freq_cpu_exit(struct cpufreq_policy *policy)
{
us3_freq_target(policy, 0);
}
static struct cpufreq_driver cpufreq_us3_driver = {
.name = "UltraSPARC-III",
.init = us3_freq_cpu_init,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = us3_freq_target,
.get = us3_freq_get,
.exit = us3_freq_cpu_exit,
};
static int __init us3_freq_init(void)
{
unsigned long manuf, impl, ver;
int ret;
if (tlb_type != cheetah && tlb_type != cheetah_plus)
return -ENODEV;
__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 ||
impl == JAGUAR_IMPL ||
impl == PANTHER_IMPL)) {
us3_freq_table = kzalloc(NR_CPUS * sizeof(*us3_freq_table),
GFP_KERNEL);
if (!us3_freq_table)
return -ENOMEM;
ret = cpufreq_register_driver(&cpufreq_us3_driver);
if (ret)
kfree(us3_freq_table);
return ret;
}
return -ENODEV;
}
static void __exit us3_freq_exit(void)
{
cpufreq_unregister_driver(&cpufreq_us3_driver);
kfree(us3_freq_table);
}
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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