280 lines
6.1 KiB
C
280 lines
6.1 KiB
C
/* us3_cpufreq.c: UltraSPARC-III cpu frequency support
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*
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* Copyright (C) 2003 David S. Miller (davem@redhat.com)
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*
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* Many thanks to Dominik Brodowski for fixing up the cpufreq
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* infrastructure in order to make this driver easier to implement.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/smp.h>
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#include <linux/cpufreq.h>
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#include <linux/threads.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <asm/head.h>
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#include <asm/timer.h>
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static struct cpufreq_driver *cpufreq_us3_driver;
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struct us3_freq_percpu_info {
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struct cpufreq_frequency_table table[4];
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};
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/* Indexed by cpu number. */
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static struct us3_freq_percpu_info *us3_freq_table;
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/* UltraSPARC-III has three dividers: 1, 2, and 32. These are controlled
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* in the Safari config register.
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*/
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#define SAFARI_CFG_DIV_1 0x0000000000000000UL
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#define SAFARI_CFG_DIV_2 0x0000000040000000UL
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#define SAFARI_CFG_DIV_32 0x0000000080000000UL
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#define SAFARI_CFG_DIV_MASK 0x00000000C0000000UL
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static unsigned long read_safari_cfg(void)
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{
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unsigned long ret;
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__asm__ __volatile__("ldxa [%%g0] %1, %0"
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: "=&r" (ret)
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: "i" (ASI_SAFARI_CONFIG));
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return ret;
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}
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static void write_safari_cfg(unsigned long val)
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{
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__asm__ __volatile__("stxa %0, [%%g0] %1\n\t"
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"membar #Sync"
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: /* no outputs */
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: "r" (val), "i" (ASI_SAFARI_CONFIG)
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: "memory");
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}
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static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg)
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{
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unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
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unsigned long ret;
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switch (safari_cfg & SAFARI_CFG_DIV_MASK) {
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case SAFARI_CFG_DIV_1:
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ret = clock_tick / 1;
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break;
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case SAFARI_CFG_DIV_2:
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ret = clock_tick / 2;
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break;
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case SAFARI_CFG_DIV_32:
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ret = clock_tick / 32;
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break;
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default:
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BUG();
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};
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return ret;
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}
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static unsigned int us3_freq_get(unsigned int cpu)
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{
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cpumask_t cpus_allowed;
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unsigned long reg;
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unsigned int ret;
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if (!cpu_online(cpu))
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return 0;
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cpus_allowed = current->cpus_allowed;
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set_cpus_allowed(current, cpumask_of_cpu(cpu));
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reg = read_safari_cfg();
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ret = get_current_freq(cpu, reg);
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set_cpus_allowed(current, cpus_allowed);
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return ret;
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}
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static void us3_set_cpu_divider_index(unsigned int cpu, unsigned int index)
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{
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unsigned long new_bits, new_freq, reg;
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cpumask_t cpus_allowed;
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struct cpufreq_freqs freqs;
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if (!cpu_online(cpu))
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return;
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cpus_allowed = current->cpus_allowed;
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set_cpus_allowed(current, cpumask_of_cpu(cpu));
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new_freq = sparc64_get_clock_tick(cpu) / 1000;
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switch (index) {
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case 0:
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new_bits = SAFARI_CFG_DIV_1;
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new_freq /= 1;
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break;
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case 1:
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new_bits = SAFARI_CFG_DIV_2;
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new_freq /= 2;
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break;
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case 2:
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new_bits = SAFARI_CFG_DIV_32;
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new_freq /= 32;
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break;
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default:
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BUG();
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};
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reg = read_safari_cfg();
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freqs.old = get_current_freq(cpu, reg);
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freqs.new = new_freq;
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freqs.cpu = cpu;
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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reg &= ~SAFARI_CFG_DIV_MASK;
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reg |= new_bits;
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write_safari_cfg(reg);
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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set_cpus_allowed(current, cpus_allowed);
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}
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static int us3_freq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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unsigned int new_index = 0;
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if (cpufreq_frequency_table_target(policy,
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&us3_freq_table[policy->cpu].table[0],
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target_freq,
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relation,
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&new_index))
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return -EINVAL;
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us3_set_cpu_divider_index(policy->cpu, new_index);
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return 0;
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}
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static int us3_freq_verify(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy,
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&us3_freq_table[policy->cpu].table[0]);
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}
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static int __init us3_freq_cpu_init(struct cpufreq_policy *policy)
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{
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unsigned int cpu = policy->cpu;
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unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
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struct cpufreq_frequency_table *table =
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&us3_freq_table[cpu].table[0];
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table[0].index = 0;
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table[0].frequency = clock_tick / 1;
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table[1].index = 1;
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table[1].frequency = clock_tick / 2;
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table[2].index = 2;
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table[2].frequency = clock_tick / 32;
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table[3].index = 0;
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table[3].frequency = CPUFREQ_TABLE_END;
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policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
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policy->cpuinfo.transition_latency = 0;
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policy->cur = clock_tick;
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return cpufreq_frequency_table_cpuinfo(policy, table);
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}
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static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
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{
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if (cpufreq_us3_driver)
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us3_set_cpu_divider_index(policy->cpu, 0);
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return 0;
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}
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static int __init us3_freq_init(void)
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{
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unsigned long manuf, impl, ver;
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int ret;
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if (tlb_type != cheetah && tlb_type != cheetah_plus)
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return -ENODEV;
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__asm__("rdpr %%ver, %0" : "=r" (ver));
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manuf = ((ver >> 48) & 0xffff);
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impl = ((ver >> 32) & 0xffff);
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if (manuf == CHEETAH_MANUF &&
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(impl == CHEETAH_IMPL ||
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impl == CHEETAH_PLUS_IMPL ||
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impl == JAGUAR_IMPL ||
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impl == PANTHER_IMPL)) {
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struct cpufreq_driver *driver;
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ret = -ENOMEM;
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driver = kmalloc(sizeof(struct cpufreq_driver), GFP_KERNEL);
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if (!driver)
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goto err_out;
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memset(driver, 0, sizeof(*driver));
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us3_freq_table = kmalloc(
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(NR_CPUS * sizeof(struct us3_freq_percpu_info)),
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GFP_KERNEL);
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if (!us3_freq_table)
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goto err_out;
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memset(us3_freq_table, 0,
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(NR_CPUS * sizeof(struct us3_freq_percpu_info)));
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driver->init = us3_freq_cpu_init;
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driver->verify = us3_freq_verify;
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driver->target = us3_freq_target;
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driver->get = us3_freq_get;
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driver->exit = us3_freq_cpu_exit;
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driver->owner = THIS_MODULE,
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strcpy(driver->name, "UltraSPARC-III");
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cpufreq_us3_driver = driver;
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ret = cpufreq_register_driver(driver);
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if (ret)
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goto err_out;
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return 0;
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err_out:
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if (driver) {
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kfree(driver);
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cpufreq_us3_driver = NULL;
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}
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kfree(us3_freq_table);
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us3_freq_table = NULL;
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return ret;
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}
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return -ENODEV;
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}
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static void __exit us3_freq_exit(void)
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{
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if (cpufreq_us3_driver) {
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cpufreq_unregister_driver(cpufreq_us3_driver);
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kfree(cpufreq_us3_driver);
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cpufreq_us3_driver = NULL;
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kfree(us3_freq_table);
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us3_freq_table = NULL;
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}
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}
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MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
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MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
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MODULE_LICENSE("GPL");
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module_init(us3_freq_init);
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module_exit(us3_freq_exit);
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