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
  37         if (!dev || !wirq)
  38                 return -EINVAL;
  39
  40         spin_lock_irqsave(&dev->power.lock, flags);
  41         if (dev_WARN_ONCE(dev, dev->power.wakeirq,
  42                           "wake irq already initialized\n")) {
  43                 spin_unlock_irqrestore(&dev->power.lock, flags);
  44                 return -EEXIST;
  45         }
  46
  47         dev->power.wakeirq = wirq;
  48         device_wakeup_attach_irq(dev, wirq);
  49
  50         spin_unlock_irqrestore(&dev->power.lock, flags);
  51         return 0;
  52 }
  53
  54 /**
  55  * dev_pm_set_wake_irq - Attach device IO interrupt as wake IRQ
  56  * @dev: Device entry
  57  * @irq: Device IO interrupt
  58  *
  59  * Attach a device IO interrupt as a wake IRQ. The wake IRQ gets
  60  * automatically configured for wake-up from suspend  based
  61  * on the device specific sysfs wakeup entry. Typically called
  62  * during driver probe after calling device_init_wakeup().
  63  */
  64 int dev_pm_set_wake_irq(struct device *dev, int irq)
  65 {
  66         struct wake_irq *wirq;
  67         int err;
  68
  69         if (irq < 0)
  70                 return -EINVAL;
  71
  72         wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
  73         if (!wirq)
  74                 return -ENOMEM;
  75
  76         wirq->dev = dev;
  77         wirq->irq = irq;
  78
  79         err = dev_pm_attach_wake_irq(dev, irq, wirq);
  80         if (err)
  81                 kfree(wirq);
  82
  83         return err;
  84 }
  85 EXPORT_SYMBOL_GPL(dev_pm_set_wake_irq);
  86
  87 /**
  88  * dev_pm_clear_wake_irq - Detach a device IO interrupt wake IRQ
  89  * @dev: Device entry
  90  *
  91  * Detach a device wake IRQ and free resources.
  92  *
  93  * Note that it's OK for drivers to call this without calling
  94  * dev_pm_set_wake_irq() as all the driver instances may not have
  95  * a wake IRQ configured. This avoid adding wake IRQ specific
  96  * checks into the drivers.
  97  */
  98 void dev_pm_clear_wake_irq(struct device *dev)
  99 {
 100         struct wake_irq *wirq = dev->power.wakeirq;
 101         unsigned long flags;
 102
 103         if (!wirq)
 104                 return;
 105
 106         spin_lock_irqsave(&dev->power.lock, flags);
 107         device_wakeup_detach_irq(dev);
 108         dev->power.wakeirq = NULL;
 109         spin_unlock_irqrestore(&dev->power.lock, flags);
 110
 111         if (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED) {
 112                 free_irq(wirq->irq, wirq);
 113                 wirq->status &= ~WAKE_IRQ_DEDICATED_MASK;
 114         }
 115         kfree(wirq->name);
 116         kfree(wirq);
 117 }
 118 EXPORT_SYMBOL_GPL(dev_pm_clear_wake_irq);
 119
 120 /**
 121  * handle_threaded_wake_irq - Handler for dedicated wake-up interrupts
 122  * @irq: Device specific dedicated wake-up interrupt
 123  * @_wirq: Wake IRQ data
 124  *
 125  * Some devices have a separate wake-up interrupt in addition to the
 126  * device IO interrupt. The wake-up interrupt signals that a device
 127  * should be woken up from it's idle state. This handler uses device
 128  * specific pm_runtime functions to wake the device, and then it's
 129  * up to the device to do whatever it needs to. Note that as the
 130  * device may need to restore context and start up regulators, we
 131  * use a threaded IRQ.
 132  *
 133  * Also note that we are not resending the lost device interrupts.
 134  * We assume that the wake-up interrupt just needs to wake-up the
 135  * device, and then device's pm_runtime_resume() can deal with the
 136  * situation.
 137  */
 138 static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
 139 {
 140         struct wake_irq *wirq = _wirq;
 141         int res;
 142
 143         /* Maybe abort suspend? */
 144         if (irqd_is_wakeup_set(irq_get_irq_data(irq))) {
 145                 pm_wakeup_event(wirq->dev, 0);
 146
 147                 return IRQ_HANDLED;
 148         }
 149
 150         /* We don't want RPM_ASYNC or RPM_NOWAIT here */
 151         res = pm_runtime_resume(wirq->dev);
 152         if (res < 0)
 153                 dev_warn(wirq->dev,
 154                          "wake IRQ with no resume: %i\n", res);
 155
 156         return IRQ_HANDLED;
 157 }
 158
 159 /**
 160  * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
 161  * @dev: Device entry
 162  * @irq: Device wake-up interrupt
 163  *
 164  * Unless your hardware has separate wake-up interrupts in addition
 165  * to the device IO interrupts, you don't need this.
 166  *
 167  * Sets up a threaded interrupt handler for a device that has
 168  * a dedicated wake-up interrupt in addition to the device IO
 169  * interrupt.
 170  *
 171  * The interrupt starts disabled, and needs to be managed for
 172  * the device by the bus code or the device driver using
 173  * dev_pm_enable_wake_irq() and dev_pm_disable_wake_irq()
 174  * functions.
 175  */
 176 int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
 177 {
 178         struct wake_irq *wirq;
 179         int err;
 180
 181         if (irq < 0)
 182                 return -EINVAL;
 183
 184         wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
 185         if (!wirq)
 186                 return -ENOMEM;
 187
 188         wirq->name = kasprintf(GFP_KERNEL, "%s:wakeup", dev_name(dev));
 189         if (!wirq->name) {
 190                 err = -ENOMEM;
 191                 goto err_free;
 192         }
 193
 194         wirq->dev = dev;
 195         wirq->irq = irq;
 196         irq_set_status_flags(irq, IRQ_NOAUTOEN);
 197
 198         /* Prevent deferred spurious wakeirqs with disable_irq_nosync() */
 199         irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY);
 200
 201         /*
 202          * Consumer device may need to power up and restore state
 203          * so we use a threaded irq.
 204          */
 205         err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
 206                                    IRQF_ONESHOT, wirq->name, wirq);
 207         if (err)
 208                 goto err_free_name;
 209
 210         err = dev_pm_attach_wake_irq(dev, irq, wirq);
 211         if (err)
 212                 goto err_free_irq;
 213
 214         wirq->status = WAKE_IRQ_DEDICATED_ALLOCATED;
 215
 216         return err;
 217
 218 err_free_irq:
 219         free_irq(irq, wirq);
 220 err_free_name:
 221         kfree(wirq->name);
 222 err_free:
 223         kfree(wirq);
 224
 225         return err;
 226 }
 227 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
 228
 229 /**
 230  * dev_pm_enable_wake_irq - Enable device wake-up interrupt
 231  * @dev: Device
 232  *
 233  * Optionally called from the bus code or the device driver for
 234  * runtime_resume() to override the PM runtime core managed wake-up
 235  * interrupt handling to enable the wake-up interrupt.
 236  *
 237  * Note that for runtime_suspend()) the wake-up interrupts
 238  * should be unconditionally enabled unlike for suspend()
 239  * that is conditional.
 240  */
 241 void dev_pm_enable_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                 enable_irq(wirq->irq);
 247 }
 248 EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
 249
 250 /**
 251  * dev_pm_disable_wake_irq - Disable device wake-up interrupt
 252  * @dev: Device
 253  *
 254  * Optionally called from the bus code or the device driver for
 255  * runtime_suspend() to override the PM runtime core managed wake-up
 256  * interrupt handling to disable the wake-up interrupt.
 257  */
 258 void dev_pm_disable_wake_irq(struct device *dev)
 259 {
 260         struct wake_irq *wirq = dev->power.wakeirq;
 261
 262         if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
 263                 disable_irq_nosync(wirq->irq);
 264 }
 265 EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
 266
 267 /**
 268  * dev_pm_enable_wake_irq_check - Checks and enables wake-up interrupt
 269  * @dev: Device
 270  * @can_change_status: Can change wake-up interrupt status
 271  *
 272  * Enables wakeirq conditionally. We need to enable wake-up interrupt
 273  * lazily on the first rpm_suspend(). This is needed as the consumer device
 274  * starts in RPM_SUSPENDED state, and the the first pm_runtime_get() would
 275  * otherwise try to disable already disabled wakeirq. The wake-up interrupt
 276  * starts disabled with IRQ_NOAUTOEN set.
 277  *
 278  * Should be only called from rpm_suspend() and rpm_resume() path.
 279  * Caller must hold &dev->power.lock to change wirq->status
 280  */
 281 void dev_pm_enable_wake_irq_check(struct device *dev,
 282                                   bool can_change_status)
 283 {
 284         struct wake_irq *wirq = dev->power.wakeirq;
 285
 286         if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
 287                 return;
 288
 289         if (likely(wirq->status & WAKE_IRQ_DEDICATED_MANAGED)) {
 290                 goto enable;
 291         } else if (can_change_status) {
 292                 wirq->status |= WAKE_IRQ_DEDICATED_MANAGED;
 293                 goto enable;
 294         }
 295
 296         return;
 297
 298 enable:
 299         enable_irq(wirq->irq);
 300 }
 301
 302 /**
 303  * dev_pm_disable_wake_irq_check - Checks and disables wake-up interrupt
 304  * @dev: Device
 305  *
 306  * Disables wake-up interrupt conditionally based on status.
 307  * Should be only called from rpm_suspend() and rpm_resume() path.
 308  */
 309 void dev_pm_disable_wake_irq_check(struct device *dev)
 310 {
 311         struct wake_irq *wirq = dev->power.wakeirq;
 312
 313         if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
 314                 return;
 315
 316         if (wirq->status & WAKE_IRQ_DEDICATED_MANAGED)
 317                 disable_irq_nosync(wirq->irq);
 318 }
 319
 320 /**
 321  * dev_pm_arm_wake_irq - Arm device wake-up
 322  * @wirq: Device wake-up interrupt
 323  *
 324  * Sets up the wake-up event conditionally based on the
 325  * device_may_wake().
 326  */
 327 void dev_pm_arm_wake_irq(struct wake_irq *wirq)
 328 {
 329         if (!wirq)
 330                 return;
 331
 332         if (device_may_wakeup(wirq->dev)) {
 333                 if (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED &&
 334                     !pm_runtime_status_suspended(wirq->dev))
 335                         enable_irq(wirq->irq);
 336
 337                 enable_irq_wake(wirq->irq);
 338         }
 339 }
 340
 341 /**
 342  * dev_pm_disarm_wake_irq - Disarm device wake-up
 343  * @wirq: Device wake-up interrupt
 344  *
 345  * Clears up the wake-up event conditionally based on the
 346  * device_may_wake().
 347  */
 348 void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
 349 {
 350         if (!wirq)
 351                 return;
 352
 353         if (device_may_wakeup(wirq->dev)) {
 354                 disable_irq_wake(wirq->irq);
 355
 356                 if (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED &&
 357                     !pm_runtime_status_suspended(wirq->dev))
 358                         disable_irq_nosync(wirq->irq);
 359         }
 360 }