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1// SPDX-License-Identifier: GPL-2.02// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.3 4#include <linux/init.h>5#include <linux/interrupt.h>6#include <linux/sched_clock.h>7#include <linux/cpu.h>8#include <linux/of_irq.h>9#include <asm/reg_ops.h>10 11#include "timer-of.h"12 13#define PTIM_CCVR "cr<3, 14>"14#define PTIM_CTLR "cr<0, 14>"15#define PTIM_LVR "cr<6, 14>"16#define PTIM_TSR "cr<1, 14>"17 18static int csky_mptimer_irq;19 20static int csky_mptimer_set_next_event(unsigned long delta,21 struct clock_event_device *ce)22{23 mtcr(PTIM_LVR, delta);24 25 return 0;26}27 28static int csky_mptimer_shutdown(struct clock_event_device *ce)29{30 mtcr(PTIM_CTLR, 0);31 32 return 0;33}34 35static int csky_mptimer_oneshot(struct clock_event_device *ce)36{37 mtcr(PTIM_CTLR, 1);38 39 return 0;40}41 42static int csky_mptimer_oneshot_stopped(struct clock_event_device *ce)43{44 mtcr(PTIM_CTLR, 0);45 46 return 0;47}48 49static DEFINE_PER_CPU(struct timer_of, csky_to) = {50 .flags = TIMER_OF_CLOCK,51 .clkevt = {52 .rating = 300,53 .features = CLOCK_EVT_FEAT_PERCPU |54 CLOCK_EVT_FEAT_ONESHOT,55 .set_state_shutdown = csky_mptimer_shutdown,56 .set_state_oneshot = csky_mptimer_oneshot,57 .set_state_oneshot_stopped = csky_mptimer_oneshot_stopped,58 .set_next_event = csky_mptimer_set_next_event,59 },60};61 62static irqreturn_t csky_timer_interrupt(int irq, void *dev)63{64 struct timer_of *to = this_cpu_ptr(&csky_to);65 66 mtcr(PTIM_TSR, 0);67 68 to->clkevt.event_handler(&to->clkevt);69 70 return IRQ_HANDLED;71}72 73/*74 * clock event for percpu75 */76static int csky_mptimer_starting_cpu(unsigned int cpu)77{78 struct timer_of *to = per_cpu_ptr(&csky_to, cpu);79 80 to->clkevt.cpumask = cpumask_of(cpu);81 82 enable_percpu_irq(csky_mptimer_irq, 0);83 84 clockevents_config_and_register(&to->clkevt, timer_of_rate(to),85 2, ULONG_MAX);86 87 return 0;88}89 90static int csky_mptimer_dying_cpu(unsigned int cpu)91{92 disable_percpu_irq(csky_mptimer_irq);93 94 return 0;95}96 97/*98 * clock source99 */100static u64 notrace sched_clock_read(void)101{102 return (u64)mfcr(PTIM_CCVR);103}104 105static u64 clksrc_read(struct clocksource *c)106{107 return (u64)mfcr(PTIM_CCVR);108}109 110struct clocksource csky_clocksource = {111 .name = "csky",112 .rating = 400,113 .mask = CLOCKSOURCE_MASK(32),114 .flags = CLOCK_SOURCE_IS_CONTINUOUS,115 .read = clksrc_read,116};117 118static int __init csky_mptimer_init(struct device_node *np)119{120 int ret, cpu, cpu_rollback;121 struct timer_of *to = NULL;122 123 /*124 * Csky_mptimer is designed for C-SKY SMP multi-processors and125 * every core has it's own private irq and regs for clkevt and126 * clksrc.127 *128 * The regs is accessed by cpu instruction: mfcr/mtcr instead of129 * mmio map style. So we needn't mmio-address in dts, but we still130 * need to give clk and irq number.131 *132 * We use private irq for the mptimer and irq number is the same133 * for every core. So we use request_percpu_irq() in timer_of_init.134 */135 csky_mptimer_irq = irq_of_parse_and_map(np, 0);136 if (csky_mptimer_irq <= 0)137 return -EINVAL;138 139 ret = request_percpu_irq(csky_mptimer_irq, csky_timer_interrupt,140 "csky_mp_timer", &csky_to);141 if (ret)142 return -EINVAL;143 144 for_each_possible_cpu(cpu) {145 to = per_cpu_ptr(&csky_to, cpu);146 ret = timer_of_init(np, to);147 if (ret)148 goto rollback;149 }150 151 clocksource_register_hz(&csky_clocksource, timer_of_rate(to));152 sched_clock_register(sched_clock_read, 32, timer_of_rate(to));153 154 ret = cpuhp_setup_state(CPUHP_AP_CSKY_TIMER_STARTING,155 "clockevents/csky/timer:starting",156 csky_mptimer_starting_cpu,157 csky_mptimer_dying_cpu);158 if (ret)159 return -EINVAL;160 161 return 0;162 163rollback:164 for_each_possible_cpu(cpu_rollback) {165 if (cpu_rollback == cpu)166 break;167 168 to = per_cpu_ptr(&csky_to, cpu_rollback);169 timer_of_cleanup(to);170 }171 return -EINVAL;172}173TIMER_OF_DECLARE(csky_mptimer, "csky,mptimer", csky_mptimer_init);174