|  | // SPDX-License-Identifier: GPL-2.0-only | 
|  | /* 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) | 
|  | { | 
|  | 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(); | 
|  | } | 
|  | } | 
|  |  | 
|  | 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 void __us2e_freq_get(void *arg) | 
|  | { | 
|  | unsigned long *estar = arg; | 
|  |  | 
|  | *estar = read_hbreg(HBIRD_ESTAR_MODE_ADDR); | 
|  | } | 
|  |  | 
|  | static unsigned int us2e_freq_get(unsigned int cpu) | 
|  | { | 
|  | unsigned long clock_tick, estar; | 
|  |  | 
|  | clock_tick = sparc64_get_clock_tick(cpu) / 1000; | 
|  | if (smp_call_function_single(cpu, __us2e_freq_get, &estar, 1)) | 
|  | return 0; | 
|  |  | 
|  | return clock_tick / estar_to_divisor(estar); | 
|  | } | 
|  |  | 
|  | static void __us2e_freq_target(void *arg) | 
|  | { | 
|  | unsigned int cpu = smp_processor_id(); | 
|  | unsigned int *index = arg; | 
|  | unsigned long new_bits, new_freq; | 
|  | unsigned long clock_tick, divisor, old_divisor, estar; | 
|  |  | 
|  | 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); | 
|  | } | 
|  | } | 
|  |  | 
|  | static int us2e_freq_target(struct cpufreq_policy *policy, unsigned int index) | 
|  | { | 
|  | unsigned int cpu = policy->cpu; | 
|  |  | 
|  | return smp_call_function_single(cpu, __us2e_freq_target, &index, 1); | 
|  | } | 
|  |  | 
|  | 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; | 
|  | policy->freq_table = table; | 
|  |  | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | 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); |