--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MStar timer driver
+ *
+ * Copyright (C) 2021 Daniel Palmer
+ * Copyright (C) 2021 Romain Perier
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqreturn.h>
+#include <linux/sched_clock.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#ifdef CONFIG_ARM
+#include <linux/delay.h>
+#endif
+
+#include "timer-of.h"
+
+#define TIMER_NAME "msc313e_timer"
+
+#define MSC313E_REG_CTRL 0x00
+#define MSC313E_REG_CTRL_TIMER_EN BIT(0)
+#define MSC313E_REG_CTRL_TIMER_TRIG BIT(1)
+#define MSC313E_REG_CTRL_TIMER_INT_EN BIT(8)
+#define MSC313E_REG_TIMER_MAX_LOW 0x08
+#define MSC313E_REG_TIMER_MAX_HIGH 0x0c
+#define MSC313E_REG_COUNTER_LOW 0x10
+#define MSC313E_REG_COUNTER_HIGH 0x14
+
+#define TIMER_SYNC_TICKS 3
+
+#ifdef CONFIG_ARM
+struct msc313e_delay {
+ void __iomem *base;
+ struct delay_timer delay;
+};
+static struct msc313e_delay msc313e_delay;
+#endif
+
+static void __iomem *msc313e_clksrc;
+
+static void msc313e_timer_stop(void __iomem *base)
+{
+ writew(0, base + MSC313E_REG_CTRL);
+}
+
+static void msc313e_timer_start(void __iomem *base, bool periodic)
+{
+ u16 reg;
+
+ reg = readw(base + MSC313E_REG_CTRL);
+ if (periodic)
+ reg |= MSC313E_REG_CTRL_TIMER_EN;
+ else
+ reg |= MSC313E_REG_CTRL_TIMER_TRIG;
+ writew(reg | MSC313E_REG_CTRL_TIMER_INT_EN, base + MSC313E_REG_CTRL);
+}
+
+static void msc313e_timer_setup(void __iomem *base, unsigned long delay)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ writew(delay >> 16, base + MSC313E_REG_TIMER_MAX_HIGH);
+ writew(delay & 0xffff, base + MSC313E_REG_TIMER_MAX_LOW);
+ local_irq_restore(flags);
+}
+
+static unsigned long msc313e_timer_current_value(void __iomem *base)
+{
+ unsigned long flags;
+ u16 l, h;
+
+ local_irq_save(flags);
+ l = readw(base + MSC313E_REG_COUNTER_LOW);
+ h = readw(base + MSC313E_REG_COUNTER_HIGH);
+ local_irq_restore(flags);
+
+ return (((u32)h) << 16 | l);
+}
+
+static int msc313e_timer_clkevt_shutdown(struct clock_event_device *evt)
+{
+ struct timer_of *timer = to_timer_of(evt);
+
+ msc313e_timer_stop(timer_of_base(timer));
+
+ return 0;
+}
+
+static int msc313e_timer_clkevt_set_oneshot(struct clock_event_device *evt)
+{
+ struct timer_of *timer = to_timer_of(evt);
+
+ msc313e_timer_stop(timer_of_base(timer));
+ msc313e_timer_start(timer_of_base(timer), false);
+
+ return 0;
+}
+
+static int msc313e_timer_clkevt_set_periodic(struct clock_event_device *evt)
+{
+ struct timer_of *timer = to_timer_of(evt);
+
+ msc313e_timer_stop(timer_of_base(timer));
+ msc313e_timer_setup(timer_of_base(timer), timer_of_period(timer));
+ msc313e_timer_start(timer_of_base(timer), true);
+
+ return 0;
+}
+
+static int msc313e_timer_clkevt_next_event(unsigned long evt, struct clock_event_device *clkevt)
+{
+ struct timer_of *timer = to_timer_of(clkevt);
+
+ msc313e_timer_stop(timer_of_base(timer));
+ msc313e_timer_setup(timer_of_base(timer), evt);
+ msc313e_timer_start(timer_of_base(timer), false);
+
+ return 0;
+}
+
+static irqreturn_t msc313e_timer_clkevt_irq(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static u64 msc313e_timer_clksrc_read(struct clocksource *cs)
+{
+ return msc313e_timer_current_value(msc313e_clksrc) & cs->mask;
+}
+
+#ifdef CONFIG_ARM
+static unsigned long msc313e_read_delay_timer_read(void)
+{
+ return msc313e_timer_current_value(msc313e_delay.base);
+}
+#endif
+
+static u64 msc313e_timer_sched_clock_read(void)
+{
+ return msc313e_timer_current_value(msc313e_clksrc);
+}
+
+static struct clock_event_device msc313e_clkevt = {
+ .name = TIMER_NAME,
+ .rating = 300,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = msc313e_timer_clkevt_shutdown,
+ .set_state_periodic = msc313e_timer_clkevt_set_periodic,
+ .set_state_oneshot = msc313e_timer_clkevt_set_oneshot,
+ .tick_resume = msc313e_timer_clkevt_shutdown,
+ .set_next_event = msc313e_timer_clkevt_next_event,
+};
+
+static int __init msc313e_clkevt_init(struct device_node *np)
+{
+ int ret;
+ struct timer_of *to;
+
+ to = kzalloc(sizeof(*to), GFP_KERNEL);
+ if (!to)
+ return -ENOMEM;
+
+ to->flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE;
+ to->of_irq.handler = msc313e_timer_clkevt_irq;
+ ret = timer_of_init(np, to);
+ if (ret)
+ return ret;
+
+ msc313e_clkevt.cpumask = cpu_possible_mask;
+ msc313e_clkevt.irq = to->of_irq.irq;
+ to->clkevt = msc313e_clkevt;
+
+ clockevents_config_and_register(&to->clkevt, timer_of_rate(to),
+ TIMER_SYNC_TICKS, 0xffffffff);
+ return 0;
+}
+
+static int __init msc313e_clksrc_init(struct device_node *np)
+{
+ struct timer_of to = { 0 };
+ int ret;
+ u16 reg;
+
+ to.flags = TIMER_OF_BASE | TIMER_OF_CLOCK;
+ ret = timer_of_init(np, &to);
+ if (ret)
+ return ret;
+
+ msc313e_clksrc = timer_of_base(&to);
+ reg = readw(msc313e_clksrc + MSC313E_REG_CTRL);
+ reg |= MSC313E_REG_CTRL_TIMER_EN;
+ writew(reg, msc313e_clksrc + MSC313E_REG_CTRL);
+
+#ifdef CONFIG_ARM
+ msc313e_delay.base = timer_of_base(&to);
+ msc313e_delay.delay.read_current_timer = msc313e_read_delay_timer_read;
+ msc313e_delay.delay.freq = timer_of_rate(&to);
+
+ register_current_timer_delay(&msc313e_delay.delay);
+#endif
+
+ sched_clock_register(msc313e_timer_sched_clock_read, 32, timer_of_rate(&to));
+ return clocksource_mmio_init(timer_of_base(&to), TIMER_NAME, timer_of_rate(&to), 300, 32,
+ msc313e_timer_clksrc_read);
+}
+
+static int __init msc313e_timer_init(struct device_node *np)
+{
+ int ret = 0;
+ static int num_called;
+
+ switch (num_called) {
+ case 0:
+ ret = msc313e_clksrc_init(np);
+ if (ret)
+ return ret;
+ break;
+
+ default:
+ ret = msc313e_clkevt_init(np);
+ if (ret)
+ return ret;
+ break;
+ }
+
+ num_called++;
+
+ return 0;
+}
+
+TIMER_OF_DECLARE(msc313, "mstar,msc313e-timer", msc313e_timer_init);
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