diff options
Diffstat (limited to 'drivers/cpufreq/sparc-us3-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/sparc-us3-cpufreq.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/drivers/cpufreq/sparc-us3-cpufreq.c b/drivers/cpufreq/sparc-us3-cpufreq.c new file mode 100644 index 000000000..51e3c6018 --- /dev/null +++ b/drivers/cpufreq/sparc-us3-cpufreq.c @@ -0,0 +1,224 @@ +/* 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 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 __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].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 int us3_freq_cpu_exit(struct cpufreq_policy *policy) +{ + if (cpufreq_us3_driver) + us3_freq_target(policy, 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(*driver), GFP_KERNEL); + if (!driver) + goto err_out; + + us3_freq_table = kzalloc((NR_CPUS * sizeof(*us3_freq_table)), + GFP_KERNEL); + if (!us3_freq_table) + goto err_out; + + driver->init = us3_freq_cpu_init; + driver->verify = cpufreq_generic_frequency_table_verify; + driver->target_index = us3_freq_target; + driver->get = us3_freq_get; + driver->exit = us3_freq_cpu_exit; + 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); |