[MIPS] time: Add GT641xx timer0 clockevent driver

And make use of it for Cobalt.  A few others such as the Malta could make
use of it as well.

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/Makefile

@@ -9,6 +9,7 @@ obj-y		+= cpu-probe.o branch.o entry.o genex.o irq.o process.o \
 		   time.o topology.o traps.o unaligned.o
 
 obj-$(CONFIG_CEVT_R4K)		+= cevt-r4k.o
+obj-$(CONFIG_CEVT_GT641XX)	+= cevt-gt641xx.o
 
 binfmt_irix-objs	:= irixelf.o irixinv.o irixioctl.o irixsig.o	\
 			   irix5sys.o sysirix.o

arch/mips/kernel/cevt-gt641xx.c

@@ -0,0 +1,144 @@
+/*
+ *  GT641xx clockevent routines.
+ *
+ *  Copyright (C) 2007  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <linux/clockchips.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+
+#include <asm/gt64120.h>
+#include <asm/time.h>
+
+#include <irq.h>
+
+static DEFINE_SPINLOCK(gt641xx_timer_lock);
+static unsigned int gt641xx_base_clock;
+
+void gt641xx_set_base_clock(unsigned int clock)
+{
+	gt641xx_base_clock = clock;
+}
+
+int gt641xx_timer0_state(void)
+{
+	if (GT_READ(GT_TC0_OFS))
+		return 0;
+
+	GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
+	GT_WRITE(GT_TC_CONTROL_OFS, GT_TC_CONTROL_ENTC0_MSK);
+
+	return 1;
+}
+
+static int gt641xx_timer0_set_next_event(unsigned long delta,
+					 struct clock_event_device *evt)
+{
+	unsigned long flags;
+	u32 ctrl;
+
+	spin_lock_irqsave(&gt641xx_timer_lock, flags);
+
+	ctrl = GT_READ(GT_TC_CONTROL_OFS);
+	ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
+	ctrl |= GT_TC_CONTROL_ENTC0_MSK;
+
+	GT_WRITE(GT_TC0_OFS, delta);
+	GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
+
+	spin_unlock_irqrestore(&gt641xx_timer_lock, flags);
+
+	return 0;
+}
+
+static void gt641xx_timer0_set_mode(enum clock_event_mode mode,
+				    struct clock_event_device *evt)
+{
+	unsigned long flags;
+	u32 ctrl;
+
+	spin_lock_irqsave(&gt641xx_timer_lock, flags);
+
+	ctrl = GT_READ(GT_TC_CONTROL_OFS);
+	ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		ctrl |= GT_TC_CONTROL_ENTC0_MSK;
+		break;
+	default:
+		break;
+	}
+
+	GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
+
+	spin_unlock_irqrestore(&gt641xx_timer_lock, flags);
+}
+
+static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
+{
+}
+
+static struct clock_event_device gt641xx_timer0_clockevent = {
+	.name		= "gt641xx-timer0",
+	.features	= CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+	.cpumask	= CPU_MASK_CPU0,
+	.irq		= GT641XX_TIMER0_IRQ,
+	.set_next_event	= gt641xx_timer0_set_next_event,
+	.set_mode	= gt641xx_timer0_set_mode,
+	.event_handler	= gt641xx_timer0_event_handler,
+};
+
+static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *cd = &gt641xx_timer0_clockevent;
+
+	cd->event_handler(cd);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction gt641xx_timer0_irqaction = {
+	.handler	= gt641xx_timer0_interrupt,
+	.flags		= IRQF_DISABLED | IRQF_PERCPU,
+	.name		= "gt641xx_timer0",
+};
+
+static int __init gt641xx_timer0_clockevent_init(void)
+{
+	struct clock_event_device *cd;
+
+	if (!gt641xx_base_clock)
+		return 0;
+
+	GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
+
+	cd = &gt641xx_timer0_clockevent;
+	cd->rating = 200 + gt641xx_base_clock / 10000000;
+	cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
+	cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
+	clockevent_set_clock(cd, gt641xx_base_clock);
+
+	clockevents_register_device(&gt641xx_timer0_clockevent);
+
+	return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
+}
+arch_initcall(gt641xx_timer0_clockevent_init);