1 files changed, 153 insertions, 0 deletions

diff --git a/arch/mips/ralink/cevt-rt3352.c b/arch/mips/ralink/cevt-rt3352.c
new file mode 100644
index 000000000..269d4877d
--- /dev/null
+++ b/arch/mips/ralink/cevt-rt3352.c
@@ -0,0 +1,153 @@
+/*
+ * 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 <john@phrozen.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 int systick_set_oneshot(struct clock_event_device *evt);
+static int systick_shutdown(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, 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_state_shutdown     = systick_shutdown,
+                .set_state_oneshot      = systick_set_oneshot,
+                .event_handler          = systick_event_handler,
+        },
+};
+
+static int systick_shutdown(struct clock_event_device *evt)
+{
+        struct systick_device *sdev;
+
+        sdev = container_of(evt, struct systick_device, dev);
+
+        if (sdev->irq_requested)
+                free_irq(systick.dev.irq, &systick.dev);
+        sdev->irq_requested = 0;
+        iowrite32(0, systick.membase + SYSTICK_CONFIG);
+
+        return 0;
+}
+
+static int systick_set_oneshot(struct clock_event_device *evt)
+{
+        const char *name = systick.dev.name;
+        struct systick_device *sdev;
+        int irq = systick.dev.irq;
+
+        sdev = container_of(evt, struct systick_device, dev);
+
+        if (!sdev->irq_requested) {
+                if (request_irq(irq, systick_interrupt,
+                                IRQF_PERCPU | IRQF_TIMER, name, &systick.dev))
+                        pr_err("Failed to request irq %d (%s)\n", irq, name);
+        }
+        sdev->irq_requested = 1;
+        iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
+                  systick.membase + SYSTICK_CONFIG);
+
+        return 0;
+}
+
+static int __init ralink_systick_init(struct device_node *np)
+{
+        int ret;
+
+        systick.membase = of_iomap(np, 0);
+        if (!systick.membase)
+                return -ENXIO;
+
+        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.max_delta_ticks = 0x7fff;
+        systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
+        systick.dev.min_delta_ticks = 0x3;
+        systick.dev.irq = irq_of_parse_and_map(np, 0);
+        if (!systick.dev.irq) {
+                pr_err("%pOFn: request_irq failed", np);
+                return -EINVAL;
+        }
+
+        ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
+                                    SYSTICK_FREQ, 301, 16,
+                                    clocksource_mmio_readl_up);
+        if (ret)
+                return ret;
+
+        clockevents_register_device(&systick.dev);
+
+        pr_info("%pOFn: running - mult: %d, shift: %d\n",
+                        np, systick.dev.mult, systick.dev.shift);
+
+        return 0;
+}
+
+TIMER_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);