diff options
Diffstat (limited to 'drivers/clocksource/timer-of.c')
| -rw-r--r-- | drivers/clocksource/timer-of.c | 230 |
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); +} |