drivers/base/power/wakeirq.c

   1 /*
   2  * wakeirq.c - Device wakeirq helper functions
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/device.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/irq.h>
  17 #include <linux/slab.h>
  18 #include <linux/pm_runtime.h>
  19 #include <linux/pm_wakeirq.h>
  20
  21 #include "power.h"
  22
  23 /**
  24  * dev_pm_attach_wake_irq - Attach device interrupt as a wake IRQ
  25  * @dev: Device entry
  26  * @irq: Device wake-up capable interrupt
  27  * @wirq: Wake irq specific data
  28  *
  29  * Internal function to attach either a device IO interrupt or a
  30  * dedicated wake-up interrupt as a wake IRQ.
  31  */
  32 static int dev_pm_attach_wake_irq(struct device *dev, int irq,
  33                                   struct wake_irq *wirq)
  34 {
  35         unsigned long flags;
  36         int err;
  37
  38         if (!dev || !wirq)
  39                 return -EINVAL;
  40
  41         spin_lock_irqsave(&dev->power.lock, flags);
  42         if (dev_WARN_ONCE(dev, dev->power.wakeirq,
  43                           "wake irq already initialized\n")) {
  44                 spin_unlock_irqrestore(&dev->power.lock, flags);
  45                 return -EEXIST;
  46         }
  47
  48         err = device_wakeup_attach_irq(dev, wirq);
  49         if (!err)
  50                 dev->power.wakeirq = wirq;
  51
  52         spin_unlock_irqrestore(&dev->power.lock, flags);
  53         return err;
  54 }
  55
  56 /**
  57  * dev_pm_set_wake_irq - Attach device IO interrupt as wake IRQ
  58  * @dev: Device entry
  59  * @irq: Device IO interrupt
  60  *
  61  * Attach a device IO interrupt as a wake IRQ. The wake IRQ gets
  62  * automatically configured for wake-up from suspend  based
  63  * on the device specific sysfs wakeup entry. Typically called
  64  * during driver probe after calling device_init_wakeup().
  65  */
  66 int dev_pm_set_wake_irq(struct device *dev, int irq)
  67 {
  68         struct wake_irq *wirq;
  69         int err;
  70
  71         if (irq < 0)
  72                 return -EINVAL;
  73
  74         wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
  75         if (!wirq)
  76                 return -ENOMEM;
  77
  78         wirq->dev = dev;
  79         wirq->irq = irq;
  80
  81         err = dev_pm_attach_wake_irq(dev, irq, wirq);
  82         if (err)
  83                 kfree(wirq);
  84
  85         return err;
  86 }
  87 EXPORT_SYMBOL_GPL(dev_pm_set_wake_irq);
  88
  89 /**
  90  * dev_pm_clear_wake_irq - Detach a device IO interrupt wake IRQ
  91  * @dev: Device entry
  92  *
  93  * Detach a device wake IRQ and free resources.
  94  *
  95  * Note that it's OK for drivers to call this without calling
  96  * dev_pm_set_wake_irq() as all the driver instances may not have
  97  * a wake IRQ configured. This avoid adding wake IRQ specific
  98  * checks into the drivers.
  99  */
 100 void dev_pm_clear_wake_irq(struct device *dev)
 101 {
 102         struct wake_irq *wirq = dev->power.wakeirq;
 103         unsigned long flags;
 104
 105         if (!wirq)
 106                 return;
 107
 108         spin_lock_irqsave(&dev->power.lock, flags);
 109         device_wakeup_detach_irq(dev);
 110         dev->power.wakeirq = NULL;
 111         spin_unlock_irqrestore(&dev->power.lock, flags);
 112
 113         if (wirq->dedicated_irq)
 114                 free_irq(wirq->irq, wirq);
 115         kfree(wirq);
 116 }
 117 EXPORT_SYMBOL_GPL(dev_pm_clear_wake_irq);
 118
 119 /**
 120  * handle_threaded_wake_irq - Handler for dedicated wake-up interrupts
 121  * @irq: Device specific dedicated wake-up interrupt
 122  * @_wirq: Wake IRQ data
 123  *
 124  * Some devices have a separate wake-up interrupt in addition to the
 125  * device IO interrupt. The wake-up interrupt signals that a device
 126  * should be woken up from it's idle state. This handler uses device
 127  * specific pm_runtime functions to wake the device, and then it's
 128  * up to the device to do whatever it needs to. Note that as the
 129  * device may need to restore context and start up regulators, we
 130  * use a threaded IRQ.
 131  *
 132  * Also note that we are not resending the lost device interrupts.
 133  * We assume that the wake-up interrupt just needs to wake-up the
 134  * device, and then device's pm_runtime_resume() can deal with the
 135  * situation.
 136  */
 137 static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
 138 {
 139         struct wake_irq *wirq = _wirq;
 140         int res;
 141
 142         /* We don't want RPM_ASYNC or RPM_NOWAIT here */
 143         res = pm_runtime_resume(wirq->dev);
 144         if (res < 0)
 145                 dev_warn(wirq->dev,
 146                          "wake IRQ with no resume: %i\n", res);
 147
 148         return IRQ_HANDLED;
 149 }
 150
 151 /**
 152  * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
 153  * @dev: Device entry
 154  * @irq: Device wake-up interrupt
 155  *
 156  * Unless your hardware has separate wake-up interrupts in addition
 157  * to the device IO interrupts, you don't need this.
 158  *
 159  * Sets up a threaded interrupt handler for a device that has
 160  * a dedicated wake-up interrupt in addition to the device IO
 161  * interrupt.
 162  *
 163  * The interrupt starts disabled, and needs to be managed for
 164  * the device by the bus code or the device driver using
 165  * dev_pm_enable_wake_irq() and dev_pm_disable_wake_irq()
 166  * functions.
 167  */
 168 int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
 169 {
 170         struct wake_irq *wirq;
 171         int err;
 172
 173         if (irq < 0)
 174                 return -EINVAL;
 175
 176         wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
 177         if (!wirq)
 178                 return -ENOMEM;
 179
 180         wirq->dev = dev;
 181         wirq->irq = irq;
 182         wirq->dedicated_irq = true;
 183         irq_set_status_flags(irq, IRQ_NOAUTOEN);
 184
 185         /*
 186          * Consumer device may need to power up and restore state
 187          * so we use a threaded irq.
 188          */
 189         err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
 190                                    IRQF_ONESHOT, dev_name(dev), wirq);
 191         if (err)
 192                 goto err_free;
 193
 194         err = dev_pm_attach_wake_irq(dev, irq, wirq);
 195         if (err)
 196                 goto err_free_irq;
 197
 198         return err;
 199
 200 err_free_irq:
 201         free_irq(irq, wirq);
 202 err_free:
 203         kfree(wirq);
 204
 205         return err;
 206 }
 207 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
 208
 209 /**
 210  * dev_pm_enable_wake_irq - Enable device wake-up interrupt
 211  * @dev: Device
 212  *
 213  * Called from the bus code or the device driver for
 214  * runtime_suspend() to enable the wake-up interrupt while
 215  * the device is running.
 216  *
 217  * Note that for runtime_suspend()) the wake-up interrupts
 218  * should be unconditionally enabled unlike for suspend()
 219  * that is conditional.
 220  */
 221 void dev_pm_enable_wake_irq(struct device *dev)
 222 {
 223         struct wake_irq *wirq = dev->power.wakeirq;
 224
 225         if (wirq && wirq->dedicated_irq)
 226                 enable_irq(wirq->irq);
 227 }
 228 EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
 229
 230 /**
 231  * dev_pm_disable_wake_irq - Disable device wake-up interrupt
 232  * @dev: Device
 233  *
 234  * Called from the bus code or the device driver for
 235  * runtime_resume() to disable the wake-up interrupt while
 236  * the device is running.
 237  */
 238 void dev_pm_disable_wake_irq(struct device *dev)
 239 {
 240         struct wake_irq *wirq = dev->power.wakeirq;
 241
 242         if (wirq && wirq->dedicated_irq)
 243                 disable_irq_nosync(wirq->irq);
 244 }
 245 EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
 246
 247 /**
 248  * dev_pm_arm_wake_irq - Arm device wake-up
 249  * @wirq: Device wake-up interrupt
 250  *
 251  * Sets up the wake-up event conditionally based on the
 252  * device_may_wake().
 253  */
 254 void dev_pm_arm_wake_irq(struct wake_irq *wirq)
 255 {
 256         if (!wirq)
 257                 return;
 258
 259         if (device_may_wakeup(wirq->dev))
 260                 enable_irq_wake(wirq->irq);
 261 }
 262
 263 /**
 264  * dev_pm_disarm_wake_irq - Disarm device wake-up
 265  * @wirq: Device wake-up interrupt
 266  *
 267  * Clears up the wake-up event conditionally based on the
 268  * device_may_wake().
 269  */
 270 void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
 271 {
 272         if (!wirq)
 273                 return;
 274
 275         if (device_may_wakeup(wirq->dev))
 276                 disable_irq_wake(wirq->irq);
 277 }