System Tick Counter is present on Ralink SoCs RT3352 and MT7620. This
driver has been in 'arch/mips/ralink' directory since the beggining of
Ralink architecture support. However, it can be moved into a more proper
place in 'drivers/clocksource'. Hence add it here adding also support for
compile test targets.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx>
---
drivers/clocksource/Kconfig | 10 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-ralink.c | 150 +++++++++++++++++++++++++++++
3 files changed, 161 insertions(+)
create mode 100644 drivers/clocksource/timer-ralink.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 95dd4660b5b6..50339f4d3201 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -753,4 +753,14 @@ config EP93XX_TIMER
Enables support for the Cirrus Logic timer block
EP93XX.
+config CLKSRC_RALINK
+ bool "Ralink System Tick Counter"
+ depends on SOC_RT305X || SOC_MT7620 || COMPILE_TEST
+ default y if SOC_RT305X || SOC_MT7620
+ select CLKSRC_MMIO
+ select TIMER_OF
+ help
+ Enables support for system tick counter present on
+ Ralink SoCs RT3352 and MT7620.
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 22743785299e..c9214afcb712 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -91,3 +91,4 @@ obj-$(CONFIG_GOLDFISH_TIMER) += timer-goldfish.o
obj-$(CONFIG_GXP_TIMER) += timer-gxp.o
obj-$(CONFIG_CLKSRC_LOONGSON1_PWM) += timer-loongson1-pwm.o
obj-$(CONFIG_EP93XX_TIMER) += timer-ep93xx.o
+obj-$(CONFIG_CLKSRC_RALINK) += timer-ralink.o
diff --git a/drivers/clocksource/timer-ralink.c b/drivers/clocksource/timer-ralink.c
new file mode 100644
index 000000000000..6ecdb4228f76
--- /dev/null
+++ b/drivers/clocksource/timer-ralink.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Ralink System Tick Counter driver present on RT3352 and MT7620 SoCs.
+ *
+ * Copyright (C) 2013 by John Crispin <john@xxxxxxxxxxx>
+ */
+
+#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>
+
+#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);
--
2.25.1
