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path: root/drivers/clocksource/timer-integrator-ap.c
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Diffstat (limited to 'drivers/clocksource/timer-integrator-ap.c')
-rw-r--r--drivers/clocksource/timer-integrator-ap.c225
1 files changed, 225 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-integrator-ap.c b/drivers/clocksource/timer-integrator-ap.c
new file mode 100644
index 0000000000..a4c700b11d
--- /dev/null
+++ b/drivers/clocksource/timer-integrator-ap.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Integrator/AP timer driver
+ * Copyright (C) 2000-2003 Deep Blue Solutions Ltd
+ * Copyright (c) 2014, Linaro Limited
+ */
+
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/sched_clock.h>
+
+#include "timer-sp.h"
+
+static void __iomem * sched_clk_base;
+
+static u64 notrace integrator_read_sched_clock(void)
+{
+ return -readl(sched_clk_base + TIMER_VALUE);
+}
+
+static int __init integrator_clocksource_init(unsigned long inrate,
+ void __iomem *base)
+{
+ u32 ctrl = TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC;
+ unsigned long rate = inrate;
+ int ret;
+
+ if (rate >= 1500000) {
+ rate /= 16;
+ ctrl |= TIMER_CTRL_DIV16;
+ }
+
+ writel(0xffff, base + TIMER_LOAD);
+ writel(ctrl, base + TIMER_CTRL);
+
+ ret = clocksource_mmio_init(base + TIMER_VALUE, "timer2",
+ rate, 200, 16, clocksource_mmio_readl_down);
+ if (ret)
+ return ret;
+
+ sched_clk_base = base;
+ sched_clock_register(integrator_read_sched_clock, 16, rate);
+
+ return 0;
+}
+
+static unsigned long timer_reload;
+static void __iomem * clkevt_base;
+
+/*
+ * IRQ handler for the timer
+ */
+static irqreturn_t integrator_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ /* clear the interrupt */
+ writel(1, clkevt_base + TIMER_INTCLR);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static int clkevt_shutdown(struct clock_event_device *evt)
+{
+ u32 ctrl = readl(clkevt_base + TIMER_CTRL) & ~TIMER_CTRL_ENABLE;
+
+ /* Disable timer */
+ writel(ctrl, clkevt_base + TIMER_CTRL);
+ return 0;
+}
+
+static int clkevt_set_oneshot(struct clock_event_device *evt)
+{
+ u32 ctrl = readl(clkevt_base + TIMER_CTRL) &
+ ~(TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC);
+
+ /* Leave the timer disabled, .set_next_event will enable it */
+ writel(ctrl, clkevt_base + TIMER_CTRL);
+ return 0;
+}
+
+static int clkevt_set_periodic(struct clock_event_device *evt)
+{
+ u32 ctrl = readl(clkevt_base + TIMER_CTRL) & ~TIMER_CTRL_ENABLE;
+
+ /* Disable timer */
+ writel(ctrl, clkevt_base + TIMER_CTRL);
+
+ /* Enable the timer and start the periodic tick */
+ writel(timer_reload, clkevt_base + TIMER_LOAD);
+ ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
+ writel(ctrl, clkevt_base + TIMER_CTRL);
+ return 0;
+}
+
+static int clkevt_set_next_event(unsigned long next, struct clock_event_device *evt)
+{
+ unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
+
+ writel(ctrl & ~TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
+ writel(next, clkevt_base + TIMER_LOAD);
+ writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
+
+ return 0;
+}
+
+static struct clock_event_device integrator_clockevent = {
+ .name = "timer1",
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = clkevt_shutdown,
+ .set_state_periodic = clkevt_set_periodic,
+ .set_state_oneshot = clkevt_set_oneshot,
+ .tick_resume = clkevt_shutdown,
+ .set_next_event = clkevt_set_next_event,
+ .rating = 300,
+};
+
+static int integrator_clockevent_init(unsigned long inrate,
+ void __iomem *base, int irq)
+{
+ unsigned long rate = inrate;
+ unsigned int ctrl = 0;
+ int ret;
+
+ clkevt_base = base;
+ /* Calculate and program a divisor */
+ if (rate > 0x100000 * HZ) {
+ rate /= 256;
+ ctrl |= TIMER_CTRL_DIV256;
+ } else if (rate > 0x10000 * HZ) {
+ rate /= 16;
+ ctrl |= TIMER_CTRL_DIV16;
+ }
+ timer_reload = rate / HZ;
+ writel(ctrl, clkevt_base + TIMER_CTRL);
+
+ ret = request_irq(irq, integrator_timer_interrupt,
+ IRQF_TIMER | IRQF_IRQPOLL, "timer",
+ &integrator_clockevent);
+ if (ret)
+ return ret;
+
+ clockevents_config_and_register(&integrator_clockevent,
+ rate,
+ 1,
+ 0xffffU);
+ return 0;
+}
+
+static int __init integrator_ap_timer_init_of(struct device_node *node)
+{
+ const char *path;
+ void __iomem *base;
+ int err;
+ int irq;
+ struct clk *clk;
+ unsigned long rate;
+ struct device_node *alias_node;
+
+ base = of_io_request_and_map(node, 0, "integrator-timer");
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ clk = of_clk_get(node, 0);
+ if (IS_ERR(clk)) {
+ pr_err("No clock for %pOFn\n", node);
+ return PTR_ERR(clk);
+ }
+ clk_prepare_enable(clk);
+ rate = clk_get_rate(clk);
+ writel(0, base + TIMER_CTRL);
+
+ err = of_property_read_string(of_aliases,
+ "arm,timer-primary", &path);
+ if (err) {
+ pr_warn("Failed to read property\n");
+ return err;
+ }
+
+ alias_node = of_find_node_by_path(path);
+
+ /*
+ * The pointer is used as an identifier not as a pointer, we
+ * can drop the refcount on the of__node immediately after
+ * getting it.
+ */
+ of_node_put(alias_node);
+
+ if (node == alias_node)
+ /* The primary timer lacks IRQ, use as clocksource */
+ return integrator_clocksource_init(rate, base);
+
+ err = of_property_read_string(of_aliases,
+ "arm,timer-secondary", &path);
+ if (err) {
+ pr_warn("Failed to read property\n");
+ return err;
+ }
+
+ alias_node = of_find_node_by_path(path);
+
+ of_node_put(alias_node);
+
+ if (node == alias_node) {
+ /* The secondary timer will drive the clock event */
+ irq = irq_of_parse_and_map(node, 0);
+ return integrator_clockevent_init(rate, base, irq);
+ }
+
+ pr_info("Timer @%p unused\n", base);
+ clk_disable_unprepare(clk);
+
+ return 0;
+}
+
+TIMER_OF_DECLARE(integrator_ap_timer, "arm,integrator-timer",
+ integrator_ap_timer_init_of);