1 files changed, 232 insertions, 0 deletions
diff --git a/arch/mips/loongson32/common/time.c b/arch/mips/loongson32/common/time.c
new file mode 100644
index 000000000..459b15c96
--- /dev/null
+++ b/arch/mips/loongson32/common/time.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2014 Zhang, Keguang <keguang.zhang@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/sizes.h>
+#include <asm/time.h>
+
+#include <loongson1.h>
+#include <platform.h>
+
+#ifdef CONFIG_CEVT_CSRC_LS1X
+
+#if defined(CONFIG_TIMER_USE_PWM1)
+#define LS1X_TIMER_BASE	LS1X_PWM1_BASE
+#define LS1X_TIMER_IRQ	LS1X_PWM1_IRQ
+
+#elif defined(CONFIG_TIMER_USE_PWM2)
+#define LS1X_TIMER_BASE	LS1X_PWM2_BASE
+#define LS1X_TIMER_IRQ	LS1X_PWM2_IRQ
+
+#elif defined(CONFIG_TIMER_USE_PWM3)
+#define LS1X_TIMER_BASE	LS1X_PWM3_BASE
+#define LS1X_TIMER_IRQ	LS1X_PWM3_IRQ
+
+#else
+#define LS1X_TIMER_BASE	LS1X_PWM0_BASE
+#define LS1X_TIMER_IRQ	LS1X_PWM0_IRQ
+#endif
+
+DEFINE_RAW_SPINLOCK(ls1x_timer_lock);
+
+static void __iomem *timer_reg_base;
+static uint32_t ls1x_jiffies_per_tick;
+
+static inline void ls1x_pwmtimer_set_period(uint32_t period)
+{
+	__raw_writel(period, timer_reg_base + PWM_HRC);
+	__raw_writel(period, timer_reg_base + PWM_LRC);
+}
+
+static inline void ls1x_pwmtimer_restart(void)
+{
+	__raw_writel(0x0, timer_reg_base + PWM_CNT);
+	__raw_writel(INT_EN | CNT_EN, timer_reg_base + PWM_CTRL);
+}
+
+void __init ls1x_pwmtimer_init(void)
+{
+	timer_reg_base = ioremap(LS1X_TIMER_BASE, SZ_16);
+	if (!timer_reg_base)
+		panic("Failed to remap timer registers");
+
+	ls1x_jiffies_per_tick = DIV_ROUND_CLOSEST(mips_hpt_frequency, HZ);
+
+	ls1x_pwmtimer_set_period(ls1x_jiffies_per_tick);
+	ls1x_pwmtimer_restart();
+}
+
+static u64 ls1x_clocksource_read(struct clocksource *cs)
+{
+	unsigned long flags;
+	int count;
+	u32 jifs;
+	static int old_count;
+	static u32 old_jifs;
+
+	raw_spin_lock_irqsave(&ls1x_timer_lock, flags);
+	/*
+	 * Although our caller may have the read side of xtime_lock,
+	 * this is now a seqlock, and we are cheating in this routine
+	 * by having side effects on state that we cannot undo if
+	 * there is a collision on the seqlock and our caller has to
+	 * retry.  (Namely, old_jifs and old_count.)  So we must treat
+	 * jiffies as volatile despite the lock.  We read jiffies
+	 * before latching the timer count to guarantee that although
+	 * the jiffies value might be older than the count (that is,
+	 * the counter may underflow between the last point where
+	 * jiffies was incremented and the point where we latch the
+	 * count), it cannot be newer.
+	 */
+	jifs = jiffies;
+	/* read the count */
+	count = __raw_readl(timer_reg_base + PWM_CNT);
+
+	/*
+	 * It's possible for count to appear to go the wrong way for this
+	 * reason:
+	 *
+	 *  The timer counter underflows, but we haven't handled the resulting
+	 *  interrupt and incremented jiffies yet.
+	 *
+	 * Previous attempts to handle these cases intelligently were buggy, so
+	 * we just do the simple thing now.
+	 */
+	if (count < old_count && jifs == old_jifs)
+		count = old_count;
+
+	old_count = count;
+	old_jifs = jifs;
+
+	raw_spin_unlock_irqrestore(&ls1x_timer_lock, flags);
+
+	return (u64) (jifs * ls1x_jiffies_per_tick) + count;
+}
+
+static struct clocksource ls1x_clocksource = {
+	.name		= "ls1x-pwmtimer",
+	.read		= ls1x_clocksource_read,
+	.mask		= CLOCKSOURCE_MASK(24),
+	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static irqreturn_t ls1x_clockevent_isr(int irq, void *devid)
+{
+	struct clock_event_device *cd = devid;
+
+	ls1x_pwmtimer_restart();
+	cd->event_handler(cd);
+
+	return IRQ_HANDLED;
+}
+
+static int ls1x_clockevent_set_state_periodic(struct clock_event_device *cd)
+{
+	raw_spin_lock(&ls1x_timer_lock);
+	ls1x_pwmtimer_set_period(ls1x_jiffies_per_tick);
+	ls1x_pwmtimer_restart();
+	__raw_writel(INT_EN | CNT_EN, timer_reg_base + PWM_CTRL);
+	raw_spin_unlock(&ls1x_timer_lock);
+
+	return 0;
+}
+
+static int ls1x_clockevent_tick_resume(struct clock_event_device *cd)
+{
+	raw_spin_lock(&ls1x_timer_lock);
+	__raw_writel(INT_EN | CNT_EN, timer_reg_base + PWM_CTRL);
+	raw_spin_unlock(&ls1x_timer_lock);
+
+	return 0;
+}
+
+static int ls1x_clockevent_set_state_shutdown(struct clock_event_device *cd)
+{
+	raw_spin_lock(&ls1x_timer_lock);
+	__raw_writel(__raw_readl(timer_reg_base + PWM_CTRL) & ~CNT_EN,
+		     timer_reg_base + PWM_CTRL);
+	raw_spin_unlock(&ls1x_timer_lock);
+
+	return 0;
+}
+
+static int ls1x_clockevent_set_next(unsigned long evt,
+				    struct clock_event_device *cd)
+{
+	raw_spin_lock(&ls1x_timer_lock);
+	ls1x_pwmtimer_set_period(evt);
+	ls1x_pwmtimer_restart();
+	raw_spin_unlock(&ls1x_timer_lock);
+
+	return 0;
+}
+
+static struct clock_event_device ls1x_clockevent = {
+	.name			= "ls1x-pwmtimer",
+	.features		= CLOCK_EVT_FEAT_PERIODIC,
+	.rating			= 300,
+	.irq			= LS1X_TIMER_IRQ,
+	.set_next_event		= ls1x_clockevent_set_next,
+	.set_state_shutdown	= ls1x_clockevent_set_state_shutdown,
+	.set_state_periodic	= ls1x_clockevent_set_state_periodic,
+	.set_state_oneshot	= ls1x_clockevent_set_state_shutdown,
+	.tick_resume		= ls1x_clockevent_tick_resume,
+};
+
+static void __init ls1x_time_init(void)
+{
+	struct clock_event_device *cd = &ls1x_clockevent;
+	int ret;
+
+	if (!mips_hpt_frequency)
+		panic("Invalid timer clock rate");
+
+	ls1x_pwmtimer_init();
+
+	clockevent_set_clock(cd, mips_hpt_frequency);
+	cd->max_delta_ns = clockevent_delta2ns(0xffffff, cd);
+	cd->max_delta_ticks = 0xffffff;
+	cd->min_delta_ns = clockevent_delta2ns(0x000300, cd);
+	cd->min_delta_ticks = 0x000300;
+	cd->cpumask = cpumask_of(smp_processor_id());
+	clockevents_register_device(cd);
+
+	ls1x_clocksource.rating = 200 + mips_hpt_frequency / 10000000;
+	ret = clocksource_register_hz(&ls1x_clocksource, mips_hpt_frequency);
+	if (ret)
+		panic(KERN_ERR "Failed to register clocksource: %d\n", ret);
+
+	if (request_irq(LS1X_TIMER_IRQ, ls1x_clockevent_isr,
+			IRQF_PERCPU | IRQF_TIMER, "ls1x-pwmtimer",
+			&ls1x_clockevent))
+		pr_err("Failed to register ls1x-pwmtimer interrupt\n");
+}
+#endif /* CONFIG_CEVT_CSRC_LS1X */
+
+void __init plat_time_init(void)
+{
+	struct clk *clk = NULL;
+
+	/* initialize LS1X clocks */
+	ls1x_clk_init();
+
+#ifdef CONFIG_CEVT_CSRC_LS1X
+	/* setup LS1X PWM timer */
+	clk = clk_get(NULL, "ls1x-pwmtimer");
+	if (IS_ERR(clk))
+		panic("unable to get timer clock, err=%ld", PTR_ERR(clk));
+
+	mips_hpt_frequency = clk_get_rate(clk);
+	ls1x_time_init();
+#else
+	/* setup mips r4k timer */
+	clk = clk_get(NULL, "cpu_clk");
+	if (IS_ERR(clk))
+		panic("unable to get cpu clock, err=%ld", PTR_ERR(clk));
+
+	mips_hpt_frequency = clk_get_rate(clk) / 2;
+#endif /* CONFIG_CEVT_CSRC_LS1X */
+}