diff options
Diffstat (limited to 'kernel/drivers/cpufreq/sparc-us2e-cpufreq.c')
| -rw-r--r-- | kernel/drivers/cpufreq/sparc-us2e-cpufreq.c | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/kernel/drivers/cpufreq/sparc-us2e-cpufreq.c b/kernel/drivers/cpufreq/sparc-us2e-cpufreq.c new file mode 100644 index 000000000..b73feeb66 --- /dev/null +++ b/kernel/drivers/cpufreq/sparc-us2e-cpufreq.c @@ -0,0 +1,378 @@ +/* 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) +{ + unsigned long flags; + + local_irq_save(flags); + + 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(); + } + + local_irq_restore(flags); +} + +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 unsigned int us2e_freq_get(unsigned int cpu) +{ + cpumask_t cpus_allowed; + unsigned long clock_tick, estar; + + cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current)); + set_cpus_allowed_ptr(current, cpumask_of(cpu)); + + clock_tick = sparc64_get_clock_tick(cpu) / 1000; + estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR); + + set_cpus_allowed_ptr(current, &cpus_allowed); + + return clock_tick / estar_to_divisor(estar); +} + +static int us2e_freq_target(struct cpufreq_policy *policy, unsigned int index) +{ + unsigned int cpu = policy->cpu; + unsigned long new_bits, new_freq; + unsigned long clock_tick, divisor, old_divisor, estar; + cpumask_t cpus_allowed; + + cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current)); + set_cpus_allowed_ptr(current, cpumask_of(cpu)); + + 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); + + set_cpus_allowed_ptr(current, &cpus_allowed); + + return 0; +} + +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; + + return cpufreq_table_validate_and_show(policy, table); +} + +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); |