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path: root/drivers/clocksource/timer-goldfish.c
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-rw-r--r--drivers/clocksource/timer-goldfish.c153
1 files changed, 153 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-goldfish.c b/drivers/clocksource/timer-goldfish.c
new file mode 100644
index 000000000..0512d5eab
--- /dev/null
+++ b/drivers/clocksource/timer-goldfish.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/goldfish.h>
+#include <clocksource/timer-goldfish.h>
+
+struct goldfish_timer {
+ struct clocksource cs;
+ struct clock_event_device ced;
+ struct resource res;
+ void __iomem *base;
+};
+
+static struct goldfish_timer *ced_to_gf(struct clock_event_device *ced)
+{
+ return container_of(ced, struct goldfish_timer, ced);
+}
+
+static struct goldfish_timer *cs_to_gf(struct clocksource *cs)
+{
+ return container_of(cs, struct goldfish_timer, cs);
+}
+
+static u64 goldfish_timer_read(struct clocksource *cs)
+{
+ struct goldfish_timer *timerdrv = cs_to_gf(cs);
+ void __iomem *base = timerdrv->base;
+ u32 time_low, time_high;
+ u64 ticks;
+
+ /*
+ * time_low: get low bits of current time and update time_high
+ * time_high: get high bits of time at last time_low read
+ */
+ time_low = gf_ioread32(base + TIMER_TIME_LOW);
+ time_high = gf_ioread32(base + TIMER_TIME_HIGH);
+
+ ticks = ((u64)time_high << 32) | time_low;
+
+ return ticks;
+}
+
+static int goldfish_timer_set_oneshot(struct clock_event_device *evt)
+{
+ struct goldfish_timer *timerdrv = ced_to_gf(evt);
+ void __iomem *base = timerdrv->base;
+
+ gf_iowrite32(0, base + TIMER_ALARM_HIGH);
+ gf_iowrite32(0, base + TIMER_ALARM_LOW);
+ gf_iowrite32(1, base + TIMER_IRQ_ENABLED);
+
+ return 0;
+}
+
+static int goldfish_timer_shutdown(struct clock_event_device *evt)
+{
+ struct goldfish_timer *timerdrv = ced_to_gf(evt);
+ void __iomem *base = timerdrv->base;
+
+ gf_iowrite32(0, base + TIMER_IRQ_ENABLED);
+
+ return 0;
+}
+
+static int goldfish_timer_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ struct goldfish_timer *timerdrv = ced_to_gf(evt);
+ void __iomem *base = timerdrv->base;
+ u64 now;
+
+ now = goldfish_timer_read(&timerdrv->cs);
+
+ now += delta;
+
+ gf_iowrite32(upper_32_bits(now), base + TIMER_ALARM_HIGH);
+ gf_iowrite32(lower_32_bits(now), base + TIMER_ALARM_LOW);
+
+ return 0;
+}
+
+static irqreturn_t goldfish_timer_irq(int irq, void *dev_id)
+{
+ struct goldfish_timer *timerdrv = dev_id;
+ struct clock_event_device *evt = &timerdrv->ced;
+ void __iomem *base = timerdrv->base;
+
+ gf_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+int __init goldfish_timer_init(int irq, void __iomem *base)
+{
+ struct goldfish_timer *timerdrv;
+ int ret;
+
+ timerdrv = kzalloc(sizeof(*timerdrv), GFP_KERNEL);
+ if (!timerdrv)
+ return -ENOMEM;
+
+ timerdrv->base = base;
+
+ timerdrv->ced = (struct clock_event_device){
+ .name = "goldfish_timer",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = goldfish_timer_shutdown,
+ .set_state_oneshot = goldfish_timer_set_oneshot,
+ .set_next_event = goldfish_timer_next_event,
+ };
+
+ timerdrv->res = (struct resource){
+ .name = "goldfish_timer",
+ .start = (unsigned long)base,
+ .end = (unsigned long)base + 0xfff,
+ };
+
+ ret = request_resource(&iomem_resource, &timerdrv->res);
+ if (ret) {
+ pr_err("Cannot allocate '%s' resource\n", timerdrv->res.name);
+ return ret;
+ }
+
+ timerdrv->cs = (struct clocksource){
+ .name = "goldfish_timer",
+ .rating = 400,
+ .read = goldfish_timer_read,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = 0,
+ .max_idle_ns = LONG_MAX,
+ };
+
+ clocksource_register_hz(&timerdrv->cs, NSEC_PER_SEC);
+
+ ret = request_irq(irq, goldfish_timer_irq, IRQF_TIMER,
+ "goldfish_timer", timerdrv);
+ if (ret) {
+ pr_err("Couldn't register goldfish-timer interrupt\n");
+ return ret;
+ }
+
+ clockevents_config_and_register(&timerdrv->ced, NSEC_PER_SEC,
+ 1, 0xffffffff);
+
+ return 0;
+}