arch/powerpc/sysdev/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
  18 struct fsl_mpic_timer_wakeup {
  19         struct mpic_timer *timer;
  20         struct work_struct free_work;
  21 };
  22
  23 static struct fsl_mpic_timer_wakeup *fsl_wakeup;
  24 static DEFINE_MUTEX(sysfs_lock);
  25
  26 static 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
  42 static 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
  51 static 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
  67 static 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         mutex_lock(&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                 mutex_unlock(&sysfs_lock);
  88                 return count;
  89         }
  90
  91         fsl_wakeup->timer = mpic_request_timer(fsl_mpic_timer_irq,
  92                                                 fsl_wakeup, interval);
  93         if (!fsl_wakeup->timer) {
  94                 mutex_unlock(&sysfs_lock);
  95                 return -EINVAL;
  96         }
  97
  98         ret = enable_irq_wake(fsl_wakeup->timer->irq);
  99         if (ret) {
 100                 mpic_free_timer(fsl_wakeup->timer);
 101                 fsl_wakeup->timer = NULL;
 102                 mutex_unlock(&sysfs_lock);
 103
 104                 return ret;
 105         }
 106
 107         mpic_start_timer(fsl_wakeup->timer);
 108
 109         mutex_unlock(&sysfs_lock);
 110
 111         return count;
 112 }
 113
 114 static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
 115                         fsl_timer_wakeup_show, fsl_timer_wakeup_store);
 116
 117 static int __init fsl_wakeup_sys_init(void)
 118 {
 119         int ret;
 120
 121         fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
 122         if (!fsl_wakeup)
 123                 return -ENOMEM;
 124
 125         INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
 126
 127         ret = device_create_file(mpic_subsys.dev_root, &mpic_attributes);
 128         if (ret)
 129                 kfree(fsl_wakeup);
 130
 131         return ret;
 132 }
 133
 134 static void __exit fsl_wakeup_sys_exit(void)
 135 {
 136         device_remove_file(mpic_subsys.dev_root, &mpic_attributes);
 137
 138         mutex_lock(&sysfs_lock);
 139
 140         if (fsl_wakeup->timer) {
 141                 disable_irq_wake(fsl_wakeup->timer->irq);
 142                 mpic_free_timer(fsl_wakeup->timer);
 143         }
 144
 145         kfree(fsl_wakeup);
 146
 147         mutex_unlock(&sysfs_lock);
 148 }
 149
 150 module_init(fsl_wakeup_sys_init);
 151 module_exit(fsl_wakeup_sys_exit);
 152
 153 MODULE_DESCRIPTION("Freescale MPIC global timer wakeup driver");
 154 MODULE_LICENSE("GPL v2");
 155 MODULE_AUTHOR("Wang Dongsheng <dongsheng.wang@freescale.com>");