fsl_mpic_timer_wakeup.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * MPIC timer wakeup driver
  4 *
  5 * Copyright 2013 Freescale Semiconductor, Inc.
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/slab.h>
 10#include <linux/errno.h>
 11#include <linux/module.h>
 12#include <linux/interrupt.h>
 13#include <linux/device.h>
 14
 15#include <asm/mpic_timer.h>
 16#include <asm/mpic.h>
 17
 18struct fsl_mpic_timer_wakeup {
 19	struct mpic_timer *timer;
 20	struct work_struct free_work;
 21};
 22
 23static struct fsl_mpic_timer_wakeup *fsl_wakeup;
 24static DEFINE_MUTEX(sysfs_lock);
 25
 26static void fsl_free_resource(struct work_struct *ws)
 27{
 28	struct fsl_mpic_timer_wakeup *wakeup =
 29		container_of(ws, struct fsl_mpic_timer_wakeup, free_work);
 30
 31	mutex_lock(&sysfs_lock);
 32
 33	if (wakeup->timer) {
 34		disable_irq_wake(wakeup->timer->irq);
 35		mpic_free_timer(wakeup->timer);
 36	}
 37
 38	wakeup->timer = NULL;
 39	mutex_unlock(&sysfs_lock);
 40}
 41
 42static irqreturn_t fsl_mpic_timer_irq(int irq, void *dev_id)
 43{
 44	struct fsl_mpic_timer_wakeup *wakeup = dev_id;
 45
 46	schedule_work(&wakeup->free_work);
 47
 48	return wakeup->timer ? IRQ_HANDLED : IRQ_NONE;
 49}
 50
 51static ssize_t fsl_timer_wakeup_show(struct device *dev,
 52				struct device_attribute *attr,
 53				char *buf)
 54{
 55	time64_t interval = 0;
 56
 57	mutex_lock(&sysfs_lock);
 58	if (fsl_wakeup->timer) {
 59		mpic_get_remain_time(fsl_wakeup->timer, &interval);
 60		interval++;
 61	}
 62	mutex_unlock(&sysfs_lock);
 63
 64	return sprintf(buf, "%lld\n", interval);
 65}
 66
 67static ssize_t fsl_timer_wakeup_store(struct device *dev,
 68				struct device_attribute *attr,
 69				const char *buf,
 70				size_t count)
 71{
 72	time64_t interval;
 73	int ret;
 74
 75	if (kstrtoll(buf, 0, &interval))
 76		return -EINVAL;
 77
 78	guard(mutex)(&sysfs_lock);
 79
 80	if (fsl_wakeup->timer) {
 81		disable_irq_wake(fsl_wakeup->timer->irq);
 82		mpic_free_timer(fsl_wakeup->timer);
 83		fsl_wakeup->timer = NULL;
 84	}
 85
 86	if (!interval)
 87		return count;
 88
 89	fsl_wakeup->timer = mpic_request_timer(fsl_mpic_timer_irq,
 90						fsl_wakeup, interval);
 91	if (!fsl_wakeup->timer)
 92		return -EINVAL;
 93
 94	ret = enable_irq_wake(fsl_wakeup->timer->irq);
 95	if (ret) {
 96		mpic_free_timer(fsl_wakeup->timer);
 97		fsl_wakeup->timer = NULL;
 98		return ret;
 99	}
100
101	mpic_start_timer(fsl_wakeup->timer);
102
103	return count;
104}
105
106static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
107			fsl_timer_wakeup_show, fsl_timer_wakeup_store);
108
109static int __init fsl_wakeup_sys_init(void)
110{
111	struct device *dev_root;
112	int ret = -EINVAL;
113
114	fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
115	if (!fsl_wakeup)
116		return -ENOMEM;
117
118	INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
119
120	dev_root = bus_get_dev_root(&mpic_subsys);
121	if (dev_root) {
122		ret = device_create_file(dev_root, &mpic_attributes);
123		put_device(dev_root);
124		if (ret)
125			kfree(fsl_wakeup);
126	}
127
128	return ret;
129}
130
131static void __exit fsl_wakeup_sys_exit(void)
132{
133	struct device *dev_root;
134
135	dev_root = bus_get_dev_root(&mpic_subsys);
136	if (dev_root) {
137		device_remove_file(dev_root, &mpic_attributes);
138		put_device(dev_root);
139	}
140
141	mutex_lock(&sysfs_lock);
142
143	if (fsl_wakeup->timer) {
144		disable_irq_wake(fsl_wakeup->timer->irq);
145		mpic_free_timer(fsl_wakeup->timer);
146	}
147
148	kfree(fsl_wakeup);
149
150	mutex_unlock(&sysfs_lock);
151}
152
153module_init(fsl_wakeup_sys_init);
154module_exit(fsl_wakeup_sys_exit);
155
156MODULE_DESCRIPTION("Freescale MPIC global timer wakeup driver");
157MODULE_LICENSE("GPL v2");
158MODULE_AUTHOR("Wang Dongsheng <dongsheng.wang@freescale.com>");