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path: root/drivers/clocksource/timer-of.c
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-rw-r--r--drivers/clocksource/timer-of.c230
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-of.c b/drivers/clocksource/timer-of.c
new file mode 100644
index 0000000000..c3f54d9912
--- /dev/null
+++ b/drivers/clocksource/timer-of.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017, Linaro Ltd. All rights reserved.
+ *
+ * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
+ */
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+
+#include "timer-of.h"
+
+/**
+ * timer_of_irq_exit - Release the interrupt
+ * @of_irq: an of_timer_irq structure pointer
+ *
+ * Free the irq resource
+ */
+static __init void timer_of_irq_exit(struct of_timer_irq *of_irq)
+{
+ struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
+
+ struct clock_event_device *clkevt = &to->clkevt;
+
+ if (of_irq->percpu)
+ free_percpu_irq(of_irq->irq, clkevt);
+ else
+ free_irq(of_irq->irq, clkevt);
+}
+
+/**
+ * timer_of_irq_init - Request the interrupt
+ * @np: a device tree node pointer
+ * @of_irq: an of_timer_irq structure pointer
+ *
+ * Get the interrupt number from the DT from its definition and
+ * request it. The interrupt is gotten by falling back the following way:
+ *
+ * - Get interrupt number by name
+ * - Get interrupt number by index
+ *
+ * When the interrupt is per CPU, 'request_percpu_irq()' is called,
+ * otherwise 'request_irq()' is used.
+ *
+ * Returns 0 on success, < 0 otherwise
+ */
+static __init int timer_of_irq_init(struct device_node *np,
+ struct of_timer_irq *of_irq)
+{
+ int ret;
+ struct timer_of *to = container_of(of_irq, struct timer_of, of_irq);
+ struct clock_event_device *clkevt = &to->clkevt;
+
+ if (of_irq->name) {
+ of_irq->irq = ret = of_irq_get_byname(np, of_irq->name);
+ if (ret < 0) {
+ pr_err("Failed to get interrupt %s for %pOF\n",
+ of_irq->name, np);
+ return ret;
+ }
+ } else {
+ of_irq->irq = irq_of_parse_and_map(np, of_irq->index);
+ }
+ if (!of_irq->irq) {
+ pr_err("Failed to map interrupt for %pOF\n", np);
+ return -EINVAL;
+ }
+
+ ret = of_irq->percpu ?
+ request_percpu_irq(of_irq->irq, of_irq->handler,
+ np->full_name, clkevt) :
+ request_irq(of_irq->irq, of_irq->handler,
+ of_irq->flags ? of_irq->flags : IRQF_TIMER,
+ np->full_name, clkevt);
+ if (ret) {
+ pr_err("Failed to request irq %d for %pOF\n", of_irq->irq, np);
+ return ret;
+ }
+
+ clkevt->irq = of_irq->irq;
+
+ return 0;
+}
+
+/**
+ * timer_of_clk_exit - Release the clock resources
+ * @of_clk: a of_timer_clk structure pointer
+ *
+ * Disables and releases the refcount on the clk
+ */
+static __init void timer_of_clk_exit(struct of_timer_clk *of_clk)
+{
+ of_clk->rate = 0;
+ clk_disable_unprepare(of_clk->clk);
+ clk_put(of_clk->clk);
+}
+
+/**
+ * timer_of_clk_init - Initialize the clock resources
+ * @np: a device tree node pointer
+ * @of_clk: a of_timer_clk structure pointer
+ *
+ * Get the clock by name or by index, enable it and get the rate
+ *
+ * Returns 0 on success, < 0 otherwise
+ */
+static __init int timer_of_clk_init(struct device_node *np,
+ struct of_timer_clk *of_clk)
+{
+ int ret;
+
+ of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) :
+ of_clk_get(np, of_clk->index);
+ if (IS_ERR(of_clk->clk)) {
+ ret = PTR_ERR(of_clk->clk);
+ if (ret != -EPROBE_DEFER)
+ pr_err("Failed to get clock for %pOF\n", np);
+ goto out;
+ }
+
+ ret = clk_prepare_enable(of_clk->clk);
+ if (ret) {
+ pr_err("Failed for enable clock for %pOF\n", np);
+ goto out_clk_put;
+ }
+
+ of_clk->rate = clk_get_rate(of_clk->clk);
+ if (!of_clk->rate) {
+ ret = -EINVAL;
+ pr_err("Failed to get clock rate for %pOF\n", np);
+ goto out_clk_disable;
+ }
+
+ of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ);
+out:
+ return ret;
+
+out_clk_disable:
+ clk_disable_unprepare(of_clk->clk);
+out_clk_put:
+ clk_put(of_clk->clk);
+
+ goto out;
+}
+
+static __init void timer_of_base_exit(struct of_timer_base *of_base)
+{
+ iounmap(of_base->base);
+}
+
+static __init int timer_of_base_init(struct device_node *np,
+ struct of_timer_base *of_base)
+{
+ of_base->base = of_base->name ?
+ of_io_request_and_map(np, of_base->index, of_base->name) :
+ of_iomap(np, of_base->index);
+ if (IS_ERR_OR_NULL(of_base->base)) {
+ pr_err("Failed to iomap (%s:%s)\n", np->name, of_base->name);
+ return of_base->base ? PTR_ERR(of_base->base) : -ENOMEM;
+ }
+
+ return 0;
+}
+
+int __init timer_of_init(struct device_node *np, struct timer_of *to)
+{
+ int ret = -EINVAL;
+ int flags = 0;
+
+ if (to->flags & TIMER_OF_BASE) {
+ ret = timer_of_base_init(np, &to->of_base);
+ if (ret)
+ goto out_fail;
+ flags |= TIMER_OF_BASE;
+ }
+
+ if (to->flags & TIMER_OF_CLOCK) {
+ ret = timer_of_clk_init(np, &to->of_clk);
+ if (ret)
+ goto out_fail;
+ flags |= TIMER_OF_CLOCK;
+ }
+
+ if (to->flags & TIMER_OF_IRQ) {
+ ret = timer_of_irq_init(np, &to->of_irq);
+ if (ret)
+ goto out_fail;
+ flags |= TIMER_OF_IRQ;
+ }
+
+ if (!to->clkevt.name)
+ to->clkevt.name = np->full_name;
+
+ to->np = np;
+
+ return ret;
+
+out_fail:
+ if (flags & TIMER_OF_IRQ)
+ timer_of_irq_exit(&to->of_irq);
+
+ if (flags & TIMER_OF_CLOCK)
+ timer_of_clk_exit(&to->of_clk);
+
+ if (flags & TIMER_OF_BASE)
+ timer_of_base_exit(&to->of_base);
+ return ret;
+}
+
+/**
+ * timer_of_cleanup - release timer_of resources
+ * @to: timer_of structure
+ *
+ * Release the resources that has been used in timer_of_init().
+ * This function should be called in init error cases
+ */
+void __init timer_of_cleanup(struct timer_of *to)
+{
+ if (to->flags & TIMER_OF_IRQ)
+ timer_of_irq_exit(&to->of_irq);
+
+ if (to->flags & TIMER_OF_CLOCK)
+ timer_of_clk_exit(&to->of_clk);
+
+ if (to->flags & TIMER_OF_BASE)
+ timer_of_base_exit(&to->of_base);
+}