Quelle  timer-of.c   Sprache: C

// 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;

 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
 *
 * 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 = 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);
}