1 files changed, 145 insertions, 0 deletions

diff --git a/kernel/arch/mips/ralink/cevt-rt3352.c b/kernel/arch/mips/ralink/cevt-rt3352.c
new file mode 100644
index 000000000..24bf057a3
--- /dev/null
+++ b/kernel/arch/mips/ralink/cevt-rt3352.c
@@ -0,0 +1,145 @@
+/*
+ * 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) 2013 by John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/reset.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+
+#define SYSTICK_FREQ		(50 * 1000)
+
+#define SYSTICK_CONFIG		0x00
+#define SYSTICK_COMPARE		0x04
+#define SYSTICK_COUNT		0x08
+
+/* route systick irq to mips irq 7 instead of the r4k-timer */
+#define CFG_EXT_STK_EN		0x2
+/* enable the counter */
+#define CFG_CNT_EN		0x1
+
+struct systick_device {
+	void __iomem *membase;
+	struct clock_event_device dev;
+	int irq_requested;
+	int freq_scale;
+};
+
+static void systick_set_clock_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt);
+
+static int systick_next_event(unsigned long delta,
+				struct clock_event_device *evt)
+{
+	struct systick_device *sdev;
+	u32 count;
+
+	sdev = container_of(evt, struct systick_device, dev);
+	count = ioread32(sdev->membase + SYSTICK_COUNT);
+	count = (count + delta) % SYSTICK_FREQ;
+	iowrite32(count + delta, sdev->membase + SYSTICK_COMPARE);
+
+	return 0;
+}
+
+static void systick_event_handler(struct clock_event_device *dev)
+{
+	/* noting to do here */
+}
+
+static irqreturn_t systick_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *dev = (struct clock_event_device *) dev_id;
+
+	dev->event_handler(dev);
+
+	return IRQ_HANDLED;
+}
+
+static struct systick_device systick = {
+	.dev = {
+		/*
+		 * cevt-r4k uses 300, make sure systick
+		 * gets used if available
+		 */
+		.rating		= 310,
+		.features	= CLOCK_EVT_FEAT_ONESHOT,
+		.set_next_event	= systick_next_event,
+		.set_mode	= systick_set_clock_mode,
+		.event_handler	= systick_event_handler,
+	},
+};
+
+static struct irqaction systick_irqaction = {
+	.handler = systick_interrupt,
+	.flags = IRQF_PERCPU | IRQF_TIMER,
+	.dev_id = &systick.dev,
+};
+
+static void systick_set_clock_mode(enum clock_event_mode mode,
+				struct clock_event_device *evt)
+{
+	struct systick_device *sdev;
+
+	sdev = container_of(evt, struct systick_device, dev);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_ONESHOT:
+		if (!sdev->irq_requested)
+			setup_irq(systick.dev.irq, &systick_irqaction);
+		sdev->irq_requested = 1;
+		iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
+				systick.membase + SYSTICK_CONFIG);
+		break;
+
+	case CLOCK_EVT_MODE_SHUTDOWN:
+		if (sdev->irq_requested)
+			free_irq(systick.dev.irq, &systick_irqaction);
+		sdev->irq_requested = 0;
+		iowrite32(0, systick.membase + SYSTICK_CONFIG);
+		break;
+
+	default:
+		pr_err("%s: Unhandeled mips clock_mode\n", systick.dev.name);
+		break;
+	}
+}
+
+static void __init ralink_systick_init(struct device_node *np)
+{
+	systick.membase = of_iomap(np, 0);
+	if (!systick.membase)
+		return;
+
+	systick_irqaction.name = np->name;
+	systick.dev.name = np->name;
+	clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
+	systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
+	systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
+	systick.dev.irq = irq_of_parse_and_map(np, 0);
+	if (!systick.dev.irq) {
+		pr_err("%s: request_irq failed", np->name);
+		return;
+	}
+
+	clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
+			SYSTICK_FREQ, 301, 16, clocksource_mmio_readl_up);
+
+	clockevents_register_device(&systick.dev);
+
+	pr_info("%s: running - mult: %d, shift: %d\n",
+			np->name, systick.dev.mult, systick.dev.shift);
+}
+
+CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);