diff options
Diffstat (limited to 'arch/sparc64/kernel/us3_cpufreq.c')
| -rw-r--r-- | arch/sparc64/kernel/us3_cpufreq.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/arch/sparc64/kernel/us3_cpufreq.c b/arch/sparc64/kernel/us3_cpufreq.c new file mode 100644 index 00000000000..18fe54b8aa5 --- /dev/null +++ b/arch/sparc64/kernel/us3_cpufreq.c @@ -0,0 +1,255 @@ +/* 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); |