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1// SPDX-License-Identifier: GPL-2.02 3#include <linux/interrupt.h>4#include <linux/ioport.h>5#include <linux/clocksource.h>6#include <linux/clockchips.h>7#include <linux/module.h>8#include <linux/slab.h>9#include <linux/goldfish.h>10#include <clocksource/timer-goldfish.h>11 12struct goldfish_timer {13 struct clocksource cs;14 struct clock_event_device ced;15 struct resource res;16 void __iomem *base;17};18 19static struct goldfish_timer *ced_to_gf(struct clock_event_device *ced)20{21 return container_of(ced, struct goldfish_timer, ced);22}23 24static struct goldfish_timer *cs_to_gf(struct clocksource *cs)25{26 return container_of(cs, struct goldfish_timer, cs);27}28 29static u64 goldfish_timer_read(struct clocksource *cs)30{31 struct goldfish_timer *timerdrv = cs_to_gf(cs);32 void __iomem *base = timerdrv->base;33 u32 time_low, time_high;34 u64 ticks;35 36 /*37 * time_low: get low bits of current time and update time_high38 * time_high: get high bits of time at last time_low read39 */40 time_low = gf_ioread32(base + TIMER_TIME_LOW);41 time_high = gf_ioread32(base + TIMER_TIME_HIGH);42 43 ticks = ((u64)time_high << 32) | time_low;44 45 return ticks;46}47 48static int goldfish_timer_set_oneshot(struct clock_event_device *evt)49{50 struct goldfish_timer *timerdrv = ced_to_gf(evt);51 void __iomem *base = timerdrv->base;52 53 gf_iowrite32(0, base + TIMER_ALARM_HIGH);54 gf_iowrite32(0, base + TIMER_ALARM_LOW);55 gf_iowrite32(1, base + TIMER_IRQ_ENABLED);56 57 return 0;58}59 60static int goldfish_timer_shutdown(struct clock_event_device *evt)61{62 struct goldfish_timer *timerdrv = ced_to_gf(evt);63 void __iomem *base = timerdrv->base;64 65 gf_iowrite32(0, base + TIMER_IRQ_ENABLED);66 67 return 0;68}69 70static int goldfish_timer_next_event(unsigned long delta,71 struct clock_event_device *evt)72{73 struct goldfish_timer *timerdrv = ced_to_gf(evt);74 void __iomem *base = timerdrv->base;75 u64 now;76 77 now = goldfish_timer_read(&timerdrv->cs);78 79 now += delta;80 81 gf_iowrite32(upper_32_bits(now), base + TIMER_ALARM_HIGH);82 gf_iowrite32(lower_32_bits(now), base + TIMER_ALARM_LOW);83 84 return 0;85}86 87static irqreturn_t goldfish_timer_irq(int irq, void *dev_id)88{89 struct goldfish_timer *timerdrv = dev_id;90 struct clock_event_device *evt = &timerdrv->ced;91 void __iomem *base = timerdrv->base;92 93 gf_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);94 95 evt->event_handler(evt);96 97 return IRQ_HANDLED;98}99 100int __init goldfish_timer_init(int irq, void __iomem *base)101{102 struct goldfish_timer *timerdrv;103 int ret;104 105 timerdrv = kzalloc(sizeof(*timerdrv), GFP_KERNEL);106 if (!timerdrv)107 return -ENOMEM;108 109 timerdrv->base = base;110 111 timerdrv->ced = (struct clock_event_device){112 .name = "goldfish_timer",113 .features = CLOCK_EVT_FEAT_ONESHOT,114 .set_state_shutdown = goldfish_timer_shutdown,115 .set_state_oneshot = goldfish_timer_set_oneshot,116 .set_next_event = goldfish_timer_next_event,117 };118 119 timerdrv->res = (struct resource){120 .name = "goldfish_timer",121 .start = (unsigned long)base,122 .end = (unsigned long)base + 0xfff,123 };124 125 ret = request_resource(&iomem_resource, &timerdrv->res);126 if (ret) {127 pr_err("Cannot allocate '%s' resource\n", timerdrv->res.name);128 return ret;129 }130 131 timerdrv->cs = (struct clocksource){132 .name = "goldfish_timer",133 .rating = 400,134 .read = goldfish_timer_read,135 .mask = CLOCKSOURCE_MASK(64),136 .flags = 0,137 .max_idle_ns = LONG_MAX,138 };139 140 clocksource_register_hz(&timerdrv->cs, NSEC_PER_SEC);141 142 ret = request_irq(irq, goldfish_timer_irq, IRQF_TIMER,143 "goldfish_timer", timerdrv);144 if (ret) {145 pr_err("Couldn't register goldfish-timer interrupt\n");146 return ret;147 }148 149 clockevents_config_and_register(&timerdrv->ced, NSEC_PER_SEC,150 1, 0xffffffff);151 152 return 0;153}154