1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Common time service routines for LoongArch machines. 4 * 5 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 6 */ 7 #include <linux/clockchips.h> 8 #include <linux/cpuhotplug.h> 9 #include <linux/delay.h> 10 #include <linux/export.h> 11 #include <linux/init.h> 12 #include <linux/interrupt.h> 13 #include <linux/kernel.h> 14 #include <linux/sched_clock.h> 15 #include <linux/spinlock.h> 16 17 #include <asm/cpu-features.h> 18 #include <asm/loongarch.h> 19 #include <asm/paravirt.h> 20 #include <asm/time.h> 21 #include <asm/timex.h> 22 23 u64 cpu_clock_freq; 24 EXPORT_SYMBOL(cpu_clock_freq); 25 u64 const_clock_freq; 26 EXPORT_SYMBOL(const_clock_freq); 27 28 static DEFINE_RAW_SPINLOCK(state_lock); 29 static DEFINE_PER_CPU(struct clock_event_device, constant_clockevent_device); 30 31 static void constant_event_handler(struct clock_event_device *dev) 32 { 33 } 34 35 static irqreturn_t constant_timer_interrupt(int irq, void *data) 36 { 37 int cpu = smp_processor_id(); 38 struct clock_event_device *cd; 39 40 /* Clear Timer Interrupt */ 41 write_csr_tintclear(CSR_TINTCLR_TI); 42 cd = &per_cpu(constant_clockevent_device, cpu); 43 cd->event_handler(cd); 44 45 return IRQ_HANDLED; 46 } 47 48 static int constant_set_state_oneshot(struct clock_event_device *evt) 49 { 50 unsigned long timer_config; 51 52 raw_spin_lock(&state_lock); 53 54 timer_config = csr_read(LOONGARCH_CSR_TCFG); 55 timer_config |= CSR_TCFG_EN; 56 timer_config &= ~CSR_TCFG_PERIOD; 57 csr_write(timer_config, LOONGARCH_CSR_TCFG); 58 59 raw_spin_unlock(&state_lock); 60 61 return 0; 62 } 63 64 static int constant_set_state_periodic(struct clock_event_device *evt) 65 { 66 unsigned long timer_config; 67 u64 period = const_clock_freq; 68 69 raw_spin_lock(&state_lock); 70 71 do_div(period, HZ); 72 timer_config = period & CSR_TCFG_VAL; 73 timer_config |= (CSR_TCFG_PERIOD | CSR_TCFG_EN); 74 csr_write(timer_config, LOONGARCH_CSR_TCFG); 75 76 raw_spin_unlock(&state_lock); 77 78 return 0; 79 } 80 81 static int constant_set_state_shutdown(struct clock_event_device *evt) 82 { 83 unsigned long timer_config; 84 85 raw_spin_lock(&state_lock); 86 87 timer_config = csr_read(LOONGARCH_CSR_TCFG); 88 timer_config &= ~CSR_TCFG_EN; 89 csr_write(timer_config, LOONGARCH_CSR_TCFG); 90 91 raw_spin_unlock(&state_lock); 92 93 return 0; 94 } 95 96 static int constant_timer_next_event(unsigned long delta, struct clock_event_device *evt) 97 { 98 unsigned long timer_config; 99 100 delta &= CSR_TCFG_VAL; 101 timer_config = delta | CSR_TCFG_EN; 102 csr_write(timer_config, LOONGARCH_CSR_TCFG); 103 104 return 0; 105 } 106 107 static int arch_timer_starting(unsigned int cpu) 108 { 109 set_csr_ecfg(ECFGF_TIMER); 110 111 return 0; 112 } 113 114 static int arch_timer_dying(unsigned int cpu) 115 { 116 /* Clear Timer Interrupt */ 117 write_csr_tintclear(CSR_TINTCLR_TI); 118 119 return 0; 120 } 121 122 static unsigned long get_loops_per_jiffy(void) 123 { 124 u64 lpj = const_clock_freq; 125 126 do_div(lpj, HZ); 127 128 return lpj; 129 } 130 131 static long init_offset; 132 133 void save_counter(void) 134 { 135 init_offset = get_cycles(); 136 } 137 138 void sync_counter(void) 139 { 140 /* Ensure counter begin at 0 */ 141 csr_write(init_offset, LOONGARCH_CSR_CNTC); 142 } 143 144 int constant_clockevent_init(void) 145 { 146 unsigned int cpu = smp_processor_id(); 147 #ifdef CONFIG_PREEMPT_RT 148 unsigned long min_delta = 100; 149 #else 150 unsigned long min_delta = 1000; 151 #endif 152 unsigned long max_delta = GENMASK_ULL(boot_cpu_data.timerbits, 0); 153 struct clock_event_device *cd; 154 static int irq = 0, timer_irq_installed = 0; 155 156 if (!timer_irq_installed) { 157 irq = get_percpu_irq(INT_TI); 158 if (irq < 0) 159 pr_err("Failed to map irq %d (timer)\n", irq); 160 } 161 162 cd = &per_cpu(constant_clockevent_device, cpu); 163 164 cd->name = "Constant"; 165 cd->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_PERCPU; 166 167 cd->irq = irq; 168 cd->rating = 320; 169 cd->cpumask = cpumask_of(cpu); 170 cd->set_state_oneshot = constant_set_state_oneshot; 171 cd->set_state_oneshot_stopped = constant_set_state_shutdown; 172 cd->set_state_periodic = constant_set_state_periodic; 173 cd->set_state_shutdown = constant_set_state_shutdown; 174 cd->set_next_event = constant_timer_next_event; 175 cd->event_handler = constant_event_handler; 176 177 clockevents_config_and_register(cd, const_clock_freq, min_delta, max_delta); 178 179 if (timer_irq_installed) 180 return 0; 181 182 timer_irq_installed = 1; 183 184 sync_counter(); 185 186 if (request_irq(irq, constant_timer_interrupt, IRQF_PERCPU | IRQF_TIMER, "timer", NULL)) 187 pr_err("Failed to request irq %d (timer)\n", irq); 188 189 lpj_fine = get_loops_per_jiffy(); 190 pr_info("Constant clock event device register\n"); 191 192 cpuhp_setup_state(CPUHP_AP_LOONGARCH_ARCH_TIMER_STARTING, 193 "clockevents/loongarch/timer:starting", 194 arch_timer_starting, arch_timer_dying); 195 196 return 0; 197 } 198 199 static u64 read_const_counter(struct clocksource *clk) 200 { 201 return get_cycles64(); 202 } 203 204 static noinstr u64 sched_clock_read(void) 205 { 206 return get_cycles64(); 207 } 208 209 static struct clocksource clocksource_const = { 210 .name = "Constant", 211 .rating = 400, 212 .read = read_const_counter, 213 .mask = CLOCKSOURCE_MASK(64), 214 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 215 #ifdef CONFIG_GENERIC_GETTIMEOFDAY 216 .vdso_clock_mode = VDSO_CLOCKMODE_CPU, 217 #endif 218 }; 219 220 int __init constant_clocksource_init(void) 221 { 222 int res; 223 unsigned long freq = const_clock_freq; 224 225 res = clocksource_register_hz(&clocksource_const, freq); 226 227 sched_clock_register(sched_clock_read, 64, freq); 228 229 pr_info("Constant clock source device register\n"); 230 231 return res; 232 } 233 234 void __init time_init(void) 235 { 236 if (!cpu_has_cpucfg) 237 const_clock_freq = cpu_clock_freq; 238 else 239 const_clock_freq = calc_const_freq(); 240 241 init_offset = -(get_cycles() - csr_read(LOONGARCH_CSR_CNTC)); 242 243 constant_clockevent_init(); 244 constant_clocksource_init(); 245 pv_time_init(); 246 } 247