[MIPS] time: Move R4000 clockevent device code to separate configurable file

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 272 insertions, 0 deletions

diff --git a/arch/mips/kernel/cevt-r4k.c b/arch/mips/kernel/cevt-r4k.c
new file mode 100644
index 0000000..08b84d4
--- /dev/null
+++ b/arch/mips/kernel/cevt-r4k.c
@@ -0,0 +1,272 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2007 MIPS Technologies, Inc.
+ * Copyright (C) 2007 Ralf Baechle <ralf@linux-mips.org>
+ */
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+
+#include <asm/time.h>
+
+static int mips_next_event(unsigned long delta,
+                           struct clock_event_device *evt)
+{
+	unsigned int cnt;
+	int res;
+
+#ifdef CONFIG_MIPS_MT_SMTC
+	{
+	unsigned long flags, vpflags;
+	local_irq_save(flags);
+	vpflags = dvpe();
+#endif
+	cnt = read_c0_count();
+	cnt += delta;
+	write_c0_compare(cnt);
+	res = ((long)(read_c0_count() - cnt ) > 0) ? -ETIME : 0;
+#ifdef CONFIG_MIPS_MT_SMTC
+	evpe(vpflags);
+	local_irq_restore(flags);
+	}
+#endif
+	return res;
+}
+
+static void mips_set_mode(enum clock_event_mode mode,
+                          struct clock_event_device *evt)
+{
+	/* Nothing to do ...  */
+}
+
+static DEFINE_PER_CPU(struct clock_event_device, mips_clockevent_device);
+static int cp0_timer_irq_installed;
+
+/*
+ * Timer ack for an R4k-compatible timer of a known frequency.
+ */
+static void c0_timer_ack(void)
+{
+	write_c0_compare(read_c0_compare());
+}
+
+/*
+ * Possibly handle a performance counter interrupt.
+ * Return true if the timer interrupt should not be checked
+ */
+static inline int handle_perf_irq(int r2)
+{
+	/*
+	 * The performance counter overflow interrupt may be shared with the
+	 * timer interrupt (cp0_perfcount_irq < 0). If it is and a
+	 * performance counter has overflowed (perf_irq() == IRQ_HANDLED)
+	 * and we can't reliably determine if a counter interrupt has also
+	 * happened (!r2) then don't check for a timer interrupt.
+	 */
+	return (cp0_perfcount_irq < 0) &&
+		perf_irq() == IRQ_HANDLED &&
+		!r2;
+}
+
+static irqreturn_t c0_compare_interrupt(int irq, void *dev_id)
+{
+	const int r2 = cpu_has_mips_r2;
+	struct clock_event_device *cd;
+	int cpu = smp_processor_id();
+
+	/*
+	 * Suckage alert:
+	 * Before R2 of the architecture there was no way to see if a
+	 * performance counter interrupt was pending, so we have to run
+	 * the performance counter interrupt handler anyway.
+	 */
+	if (handle_perf_irq(r2))
+		goto out;
+
+	/*
+	 * The same applies to performance counter interrupts.  But with the
+	 * above we now know that the reason we got here must be a timer
+	 * interrupt.  Being the paranoiacs we are we check anyway.
+	 */
+	if (!r2 || (read_c0_cause() & (1 << 30))) {
+		c0_timer_ack();
+#ifdef CONFIG_MIPS_MT_SMTC
+		if (cpu_data[cpu].vpe_id)
+			goto out;
+		cpu = 0;
+#endif
+		cd = &per_cpu(mips_clockevent_device, cpu);
+		cd->event_handler(cd);
+	}
+
+out:
+	return IRQ_HANDLED;
+}
+
+static struct irqaction c0_compare_irqaction = {
+	.handler = c0_compare_interrupt,
+#ifdef CONFIG_MIPS_MT_SMTC
+	.flags = IRQF_DISABLED,
+#else
+	.flags = IRQF_DISABLED | IRQF_PERCPU,
+#endif
+	.name = "timer",
+};
+
+#ifdef CONFIG_MIPS_MT_SMTC
+DEFINE_PER_CPU(struct clock_event_device, smtc_dummy_clockevent_device);
+
+static void smtc_set_mode(enum clock_event_mode mode,
+                          struct clock_event_device *evt)
+{
+}
+
+static void mips_broadcast(cpumask_t mask)
+{
+	unsigned int cpu;
+
+	for_each_cpu_mask(cpu, mask)
+		smtc_send_ipi(cpu, SMTC_CLOCK_TICK, 0);
+}
+
+static void setup_smtc_dummy_clockevent_device(void)
+{
+	//uint64_t mips_freq = mips_hpt_^frequency;
+	unsigned int cpu = smp_processor_id();
+	struct clock_event_device *cd;
+
+	cd = &per_cpu(smtc_dummy_clockevent_device, cpu);
+
+	cd->name		= "SMTC";
+	cd->features		= CLOCK_EVT_FEAT_DUMMY;
+
+	/* Calculate the min / max delta */
+	cd->mult	= 0; //div_sc((unsigned long) mips_freq, NSEC_PER_SEC, 32);
+	cd->shift		= 0; //32;
+	cd->max_delta_ns	= 0; //clockevent_delta2ns(0x7fffffff, cd);
+	cd->min_delta_ns	= 0; //clockevent_delta2ns(0x30, cd);
+
+	cd->rating		= 200;
+	cd->irq			= 17; //-1;
+//	if (cpu)
+//		cd->cpumask	= CPU_MASK_ALL; // cpumask_of_cpu(cpu);
+//	else
+		cd->cpumask	= cpumask_of_cpu(cpu);
+
+	cd->set_mode		= smtc_set_mode;
+
+	cd->broadcast		= mips_broadcast;
+
+	clockevents_register_device(cd);
+}
+#endif
+
+static void mips_event_handler(struct clock_event_device *dev)
+{
+}
+
+/*
+ * FIXME: This doesn't hold for the relocated E9000 compare interrupt.
+ */
+static int c0_compare_int_pending(void)
+{
+	return (read_c0_cause() >> cp0_compare_irq) & 0x100;
+}
+
+static int c0_compare_int_usable(void)
+{
+	const unsigned int delta = 0x300000;
+	unsigned int cnt;
+
+	/*
+	 * IP7 already pending?  Try to clear it by acking the timer.
+	 */
+	if (c0_compare_int_pending()) {
+		write_c0_compare(read_c0_compare());
+		irq_disable_hazard();
+		if (c0_compare_int_pending())
+			return 0;
+	}
+
+	cnt = read_c0_count();
+	cnt += delta;
+	write_c0_compare(cnt);
+
+	while ((long)(read_c0_count() - cnt) <= 0)
+		;	/* Wait for expiry  */
+
+	if (!c0_compare_int_pending())
+		return 0;
+
+	write_c0_compare(read_c0_compare());
+	irq_disable_hazard();
+	if (c0_compare_int_pending())
+		return 0;
+
+	/*
+	 * Feels like a real count / compare timer.
+	 */
+	return 1;
+}
+
+void __cpuinit mips_clockevent_init(void)
+{
+	uint64_t mips_freq = mips_hpt_frequency;
+	unsigned int cpu = smp_processor_id();
+	struct clock_event_device *cd;
+	unsigned int irq = MIPS_CPU_IRQ_BASE + 7;
+
+	if (!cpu_has_counter)
+		return;
+
+#ifdef CONFIG_MIPS_MT_SMTC
+	setup_smtc_dummy_clockevent_device();
+
+	/*
+	 * On SMTC we only register VPE0's compare interrupt as clockevent
+	 * device.
+	 */
+	if (cpu)
+		return;
+#endif
+
+	if (!c0_compare_int_usable())
+		return;
+
+	cd = &per_cpu(mips_clockevent_device, cpu);
+
+	cd->name		= "MIPS";
+	cd->features		= CLOCK_EVT_FEAT_ONESHOT;
+
+	/* Calculate the min / max delta */
+	cd->mult	= div_sc((unsigned long) mips_freq, NSEC_PER_SEC, 32);
+	cd->shift		= 32;
+	cd->max_delta_ns	= clockevent_delta2ns(0x7fffffff, cd);
+	cd->min_delta_ns	= clockevent_delta2ns(0x300, cd);
+
+	cd->rating		= 300;
+	cd->irq			= irq;
+#ifdef CONFIG_MIPS_MT_SMTC
+	cd->cpumask		= CPU_MASK_ALL;
+#else
+	cd->cpumask		= cpumask_of_cpu(cpu);
+#endif
+	cd->set_next_event	= mips_next_event;
+	cd->set_mode		= mips_set_mode;
+	cd->event_handler	= mips_event_handler;
+
+	clockevents_register_device(cd);
+
+	if (!cp0_timer_irq_installed) {
+#ifdef CONFIG_MIPS_MT_SMTC
+#define CPUCTR_IMASKBIT (0x100 << cp0_compare_irq)
+		setup_irq_smtc(irq, &c0_compare_irqaction, CPUCTR_IMASKBIT);
+#else
+		setup_irq(irq, &c0_compare_irqaction);
+#endif /* CONFIG_MIPS_MT_SMTC */
+		cp0_timer_irq_installed = 1;
+	}
+}