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->status & WAKE_IRQ_DEDICATED_ALLOCATED) {
 114                 free_irq(wirq->irq, wirq);
 115                 wirq->status &= ~WAKE_IRQ_DEDICATED_MASK;
 116         }
 117         kfree(wirq);
 118 }
 119 EXPORT_SYMBOL_GPL(dev_pm_clear_wake_irq);
 120
 121 /**
 122  * handle_threaded_wake_irq - Handler for dedicated wake-up interrupts
 123  * @irq: Device specific dedicated wake-up interrupt
 124  * @_wirq: Wake IRQ data
 125  *
 126  * Some devices have a separate wake-up interrupt in addition to the
 127  * device IO interrupt. The wake-up interrupt signals that a device
 128  * should be woken up from it's idle state. This handler uses device
 129  * specific pm_runtime functions to wake the device, and then it's
 130  * up to the device to do whatever it needs to. Note that as the
 131  * device may need to restore context and start up regulators, we
 132  * use a threaded IRQ.
 133  *
 134  * Also note that we are not resending the lost device interrupts.
 135  * We assume that the wake-up interrupt just needs to wake-up the
 136  * device, and then device's pm_runtime_resume() can deal with the
 137  * situation.
 138  */
 139 static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
 140 {
 141         struct wake_irq *wirq = _wirq;
 142         int res;
 143
 144         /* We don't want RPM_ASYNC or RPM_NOWAIT here */
 145         res = pm_runtime_resume(wirq->dev);
 146         if (res < 0)
 147                 dev_warn(wirq->dev,
 148                          "wake IRQ with no resume: %i\n", res);
 149
 150         return IRQ_HANDLED;
 151 }
 152
 153 /**
 154  * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
 155  * @dev: Device entry
 156  * @irq: Device wake-up interrupt
 157  *
 158  * Unless your hardware has separate wake-up interrupts in addition
 159  * to the device IO interrupts, you don't need this.
 160  *
 161  * Sets up a threaded interrupt handler for a device that has
 162  * a dedicated wake-up interrupt in addition to the device IO
 163  * interrupt.
 164  *
 165  * The interrupt starts disabled, and needs to be managed for
 166  * the device by the bus code or the device driver using
 167  * dev_pm_enable_wake_irq() and dev_pm_disable_wake_irq()
 168  * functions.
 169  */
 170 int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
 171 {
 172         struct wake_irq *wirq;
 173         int err;
 174
 175         if (irq < 0)
 176                 return -EINVAL;
 177
 178         wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
 179         if (!wirq)
 180                 return -ENOMEM;
 181
 182         wirq->dev = dev;
 183         wirq->irq = irq;
 184         irq_set_status_flags(irq, IRQ_NOAUTOEN);
 185
 186         /*
 187          * Consumer device may need to power up and restore state
 188          * so we use a threaded irq.
 189          */
 190         err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
 191                                    IRQF_ONESHOT, dev_name(dev), wirq);
 192         if (err)
 193                 goto err_free;
 194
 195         err = dev_pm_attach_wake_irq(dev, irq, wirq);
 196         if (err)
 197                 goto err_free_irq;
 198
 199         wirq->status = WAKE_IRQ_DEDICATED_ALLOCATED;
 200
 201         return err;
 202
 203 err_free_irq:
 204         free_irq(irq, wirq);
 205 err_free:
 206         kfree(wirq);
 207
 208         return err;
 209 }
 210 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
 211
 212 /**
 213  * dev_pm_enable_wake_irq - Enable device wake-up interrupt
 214  * @dev: Device
 215  *
 216  * Optionally called from the bus code or the device driver for
 217  * runtime_resume() to override the PM runtime core managed wake-up
 218  * interrupt handling to enable the wake-up interrupt.
 219  *
 220  * Note that for runtime_suspend()) the wake-up interrupts
 221  * should be unconditionally enabled unlike for suspend()
 222  * that is conditional.
 223  */
 224 void dev_pm_enable_wake_irq(struct device *dev)
 225 {
 226         struct wake_irq *wirq = dev->power.wakeirq;
 227
 228         if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
 229                 enable_irq(wirq->irq);
 230 }
 231 EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
 232
 233 /**
 234  * dev_pm_disable_wake_irq - Disable device wake-up interrupt
 235  * @dev: Device
 236  *
 237  * Optionally called from the bus code or the device driver for
 238  * runtime_suspend() to override the PM runtime core managed wake-up
 239  * interrupt handling to disable the wake-up interrupt.
 240  */
 241 void dev_pm_disable_wake_irq(struct device *dev)
 242 {
 243         struct wake_irq *wirq = dev->power.wakeirq;
 244
 245         if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
 246                 disable_irq_nosync(wirq->irq);
 247 }
 248 EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
 249
 250 /**
 251  * dev_pm_enable_wake_irq_check - Checks and enables wake-up interrupt
 252  * @dev: Device
 253  * @can_change_status: Can change wake-up interrupt status
 254  *
 255  * Enables wakeirq conditionally. We need to enable wake-up interrupt
 256  * lazily on the first rpm_suspend(). This is needed as the consumer device
 257  * starts in RPM_SUSPENDED state, and the the first pm_runtime_get() would
 258  * otherwise try to disable already disabled wakeirq. The wake-up interrupt
 259  * starts disabled with IRQ_NOAUTOEN set.
 260  *
 261  * Should be only called from rpm_suspend() and rpm_resume() path.
 262  * Caller must hold &dev->power.lock to change wirq->status
 263  */
 264 void dev_pm_enable_wake_irq_check(struct device *dev,
 265                                   bool can_change_status)
 266 {
 267         struct wake_irq *wirq = dev->power.wakeirq;
 268
 269         if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
 270                 return;
 271
 272         if (likely(wirq->status & WAKE_IRQ_DEDICATED_MANAGED)) {
 273                 goto enable;
 274         } else if (can_change_status) {
 275                 wirq->status |= WAKE_IRQ_DEDICATED_MANAGED;
 276                 goto enable;
 277         }
 278
 279         return;
 280
 281 enable:
 282         enable_irq(wirq->irq);
 283 }
 284
 285 /**
 286  * dev_pm_disable_wake_irq_check - Checks and disables wake-up interrupt
 287  * @dev: Device
 288  *
 289  * Disables wake-up interrupt conditionally based on status.
 290  * Should be only called from rpm_suspend() and rpm_resume() path.
 291  */
 292 void dev_pm_disable_wake_irq_check(struct device *dev)
 293 {
 294         struct wake_irq *wirq = dev->power.wakeirq;
 295
 296         if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
 297                 return;
 298
 299         if (wirq->status & WAKE_IRQ_DEDICATED_MANAGED)
 300                 disable_irq_nosync(wirq->irq);
 301 }
 302
 303 /**
 304  * dev_pm_arm_wake_irq - Arm device wake-up
 305  * @wirq: Device wake-up interrupt
 306  *
 307  * Sets up the wake-up event conditionally based on the
 308  * device_may_wake().
 309  */
 310 void dev_pm_arm_wake_irq(struct wake_irq *wirq)
 311 {
 312         if (!wirq)
 313                 return;
 314
 315         if (device_may_wakeup(wirq->dev))
 316                 enable_irq_wake(wirq->irq);
 317 }
 318
 319 /**
 320  * dev_pm_disarm_wake_irq - Disarm device wake-up
 321  * @wirq: Device wake-up interrupt
 322  *
 323  * Clears up the wake-up event conditionally based on the
 324  * device_may_wake().
 325  */
 326 void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
 327 {
 328         if (!wirq)
 329                 return;
 330
 331         if (device_may_wakeup(wirq->dev))
 332                 disable_irq_wake(wirq->irq);
 333 }