/* us2e_cpufreq.c: UltraSPARC-IIe 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/delay.h>
#include <linux/init.h>
#include <asm/asi.h>
#include <asm/timer.h>
static struct cpufreq_driver *cpufreq_us2e_driver;
struct us2e_freq_percpu_info {
struct cpufreq_frequency_table table[6];
};
/* Indexed by cpu number. */
static struct us2e_freq_percpu_info *us2e_freq_table;
#define HBIRD_MEM_CNTL0_ADDR 0x1fe0000f010UL
#define HBIRD_ESTAR_MODE_ADDR 0x1fe0000f080UL
/* UltraSPARC-IIe has five dividers: 1, 2, 4, 6, and 8. These are controlled
* in the ESTAR mode control register.
*/
#define ESTAR_MODE_DIV_1 0x0000000000000000UL
#define ESTAR_MODE_DIV_2 0x0000000000000001UL
#define ESTAR_MODE_DIV_4 0x0000000000000003UL
#define ESTAR_MODE_DIV_6 0x0000000000000002UL
#define ESTAR_MODE_DIV_8 0x0000000000000004UL
#define ESTAR_MODE_DIV_MASK 0x0000000000000007UL
#define MCTRL0_SREFRESH_ENAB 0x0000000000010000UL
#define MCTRL0_REFR_COUNT_MASK 0x0000000000007f00UL
#define MCTRL0_REFR_COUNT_SHIFT 8
#define MCTRL0_REFR_INTERVAL 7800
#define MCTRL0_REFR_CLKS_P_CNT 64
static unsigned long read_hbreg(unsigned long addr)
{
unsigned long ret;
__asm__ __volatile__("ldxa [%1] %2, %0"
: "=&r" (ret)
: "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E));
return ret;
}
static void write_hbreg(unsigned long addr, unsigned long val)
{
__asm__ __volatile__("stxa %0, [%1] %2\n\t"
"membar #Sync"
: /* no outputs */
: "r" (val), "r" (addr), "i" (ASI_PHYS_BYPASS_EC_E)
: "memory");
if (addr == HBIRD_ESTAR_MODE_ADDR) {
/* Need to wait 16 clock cycles for the PLL to lock. */
udelay(1);
}
}
static void self_refresh_ctl(int enable)
{
unsigned long mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
if (enable)
mctrl |= MCTRL0_SREFRESH_ENAB;
else
mctrl &= ~MCTRL0_SREFRESH_ENAB;
write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl);
(void) read_hbreg(HBIRD_MEM_CNTL0_ADDR);
}
static void frob_mem_refresh(int cpu_slowing_down,
unsigned long clock_tick,
unsigned long old_divisor, unsigned long divisor)
{
unsigned long old_refr_count, refr_count, mctrl;
refr_count = (clock_tick * MCTRL0_REFR_INTERVAL);
refr_count /= (MCTRL0_REFR_CLKS_P_CNT * divisor * 1000000000UL);
mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
old_refr_count = (mctrl & MCTRL0_REFR_COUNT_MASK)
>> MCTRL0_REFR_COUNT_SHIFT;
mctrl &= ~MCTRL0_REFR_COUNT_MASK;
mctrl |= refr_count << MCTRL0_REFR_COUNT_SHIFT;
write_hbreg(HBIRD_MEM_CNTL0_ADDR, mctrl);
mctrl = read_hbreg(HBIRD_MEM_CNTL0_ADDR);
if (cpu_slowing_down && !(mctrl & MCTRL0_SREFRESH_ENAB)) {
unsigned long usecs;
/* We have to wait for both refresh counts (old
* and new) to go to zero.
*/
usecs = (MCTRL0_REFR_CLKS_P_CNT *
(refr_count + old_refr_count) *
1000000UL *
old_divisor) / clock_tick;
udelay(usecs + 1UL);
}
}
static void us2e_transition(unsigned long estar, unsigned long new_bits,
unsigned long clock_tick,
unsigned long old_divisor, unsigned long divisor)
{
estar &= ~ESTAR_MODE_DIV_MASK;
/* This is based upon the state transition diagram in the IIe manual. */
if (old_divisor == 2 && divisor == 1) {
self_refresh_ctl(0);
write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
frob_mem_refresh(0, clock_tick, old_divisor, divisor);
} else if (old_divisor == 1 && divisor == 2) {
frob_mem_refresh(1, clock_tick, old_divisor, divisor);
write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
self_refresh_ctl(1);
} else if (old_divisor == 1 && divisor > 2) {
us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick,
1, 2);
us2e_transition(estar, new_bits, clock_tick,
2, divisor);
} else if (old_divisor > 2 && divisor == 1) {
us2e_transition(estar, ESTAR_MODE_DIV_2, clock_tick,
old_divisor, 2);
us2e_transition(estar, new_bits, clock_tick,
2, divisor);
} else if (old_divisor < divisor) {
frob_mem_refresh(0, clock_tick, old_divisor, divisor);
write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
} else if (old_divisor > divisor) {
write_hbreg(HBIRD_ESTAR_MODE_ADDR, estar | new_bits);
frob_mem_refresh(1, clock_tick, old_divisor, divisor);
} else {
BUG();
}
}
static unsigned long index_to_estar_mode(unsigned int index)
{
switch (index) {
case 0:
return ESTAR_MODE_DIV_1;
case 1:
return ESTAR_MODE_DIV_2;
case 2:
return ESTAR_MODE_DIV_4;
case 3:
return ESTAR_MODE_DIV_6;
case 4:
return ESTAR_MODE_DIV_8;
default:
BUG();
}
}
static unsigned long index_to_divisor(unsigned int index)
{
switch (index) {
case 0:
return 1;
case 1:
return 2;
case 2:
return 4;
case 3:
return 6;
case 4:
return 8;
default:
BUG();
}
}
static unsigned long estar_to_divisor(unsigned long estar)
{
unsigned long ret;
switch (estar & ESTAR_MODE_DIV_MASK) {
case ESTAR_MODE_DIV_1:
ret = 1;
break;
case ESTAR_MODE_DIV_2:
ret = 2;
break;
case ESTAR_MODE_DIV_4:
ret = 4;
break;
case ESTAR_MODE_DIV_6:
ret = 6;
break;
case ESTAR_MODE_DIV_8:
ret = 8;
break;
default:
BUG();
}
return ret;
}
static void __us2e_freq_get(void *arg)
{
unsigned long *estar = arg;
*estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR);
}
static unsigned int us2e_freq_get(unsigned int cpu)
{
unsigned long clock_tick, estar;
clock_tick = sparc64_get_clock_tick(cpu) / 1000;
if (smp_call_function_single(cpu, __us2e_freq_get, &estar, 1))
return 0;
return clock_tick / estar_to_divisor(estar);
}
static void __us2e_freq_target(void *arg)
{
unsigned int cpu = smp_processor_id();
unsigned int *index = arg;
unsigned long new_bits, new_freq;
unsigned long clock_tick, divisor, old_divisor, estar;
new_freq = clock_tick = sparc64_get_clock_tick(cpu) / 1000;
new_bits = index_to_estar_mode(*index);
divisor = index_to_divisor(*index);
new_freq /= divisor;
estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR);
old_divisor = estar_to_divisor(estar);
if (old_divisor != divisor) {
us2e_transition(estar, new_bits, clock_tick * 1000,
old_divisor, divisor);
}
}
static int us2e_freq_target(struct cpufreq_policy *policy, unsigned int index)
{
unsigned int cpu = policy->cpu;
return smp_call_function_single(cpu, __us2e_freq_target, &index, 1);
}
static int __init us2e_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 =
&us2e_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 / 4;
table[2].driver_data = 3;
table[2].frequency = clock_tick / 6;
table[2].driver_data = 4;
table[2].frequency = clock_tick / 8;
table[2].driver_data = 5;
table[3].frequency = CPUFREQ_TABLE_END;
policy->cpuinfo.transition_latency = 0;
policy->cur = clock_tick;
policy->freq_table = table;
return 0;
}
static int us2e_freq_cpu_exit(struct cpufreq_policy *policy)
{
if (cpufreq_us2e_driver)
us2e_freq_target(policy, 0);
return 0;
}
static int __init us2e_freq_init(void)
{
unsigned long manuf, impl, ver;
int ret;
if (tlb_type != spitfire)
return -ENODEV;
__asm__("rdpr %%ver, %0" : "=r" (ver));
manuf = ((ver >> 48) & 0xffff);
impl = ((ver >> 32) & 0xffff);
if (manuf == 0x17 && impl == 0x13) {
struct cpufreq_driver *driver;
ret = -ENOMEM;
driver = kzalloc(sizeof(*driver), GFP_KERNEL);
if (!driver)
goto err_out;
us2e_freq_table = kzalloc((NR_CPUS * sizeof(*us2e_freq_table)),
GFP_KERNEL);
if (!us2e_freq_table)
goto err_out;
driver->init = us2e_freq_cpu_init;
driver->verify = cpufreq_generic_frequency_table_verify;
driver->target_index = us2e_freq_target;
driver->get = us2e_freq_get;
driver->exit = us2e_freq_cpu_exit;
strcpy(driver->name, "UltraSPARC-IIe");
cpufreq_us2e_driver = driver;
ret = cpufreq_register_driver(driver);
if (ret)
goto err_out;
return 0;
err_out:
if (driver) {
kfree(driver);
cpufreq_us2e_driver = NULL;
}
kfree(us2e_freq_table);
us2e_freq_table = NULL;
return ret;
}
return -ENODEV;
}
static void __exit us2e_freq_exit(void)
{
if (cpufreq_us2e_driver) {
cpufreq_unregister_driver(cpufreq_us2e_driver);
kfree(cpufreq_us2e_driver);
cpufreq_us2e_driver = NULL;
kfree(us2e_freq_table);
us2e_freq_table = NULL;
}
}
MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-IIe");
MODULE_LICENSE("GPL");
module_init(us2e_freq_init);
module_exit(us2e_freq_exit);
