summaryrefslogtreecommitdiff
path: root/arch/mips/ralink/cevt-rt3352.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/ralink/cevt-rt3352.c')
-rw-r--r--arch/mips/ralink/cevt-rt3352.c145
1 files changed, 145 insertions, 0 deletions
diff --git a/arch/mips/ralink/cevt-rt3352.c b/arch/mips/ralink/cevt-rt3352.c
new file mode 100644
index 000000000000..cc17566d1934
--- /dev/null
+++ b/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: runing - mult: %d, shift: %d\n",
+ np->name, systick.dev.mult, systick.dev.shift);
+}
+
+CLOCKSOURCE_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init);