/* 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) / 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) { cpumask_t cpus_allowed; unsigned long reg; unsigned int ret; if (!cpu_online(cpu)) return 0; cpus_allowed = current->cpus_allowed; set_cpus_allowed(current, cpumask_of_cpu(cpu)); reg = read_safari_cfg(); ret = get_current_freq(cpu, reg); set_cpus_allowed(current, cpus_allowed); 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) / 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(); }; 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) / 1000; 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->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; 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)) { struct cpufreq_driver *driver; ret = -ENOMEM; driver = kzalloc(sizeof(struct cpufreq_driver), GFP_KERNEL); if (!driver) goto err_out; us3_freq_table = kzalloc( (NR_CPUS * sizeof(struct us3_freq_percpu_info)), GFP_KERNEL); if (!us3_freq_table) goto err_out; driver->init = us3_freq_cpu_init; driver->verify = us3_freq_verify; driver->target = us3_freq_target; driver->get = us3_freq_get; 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; } 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);