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);
 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         /* Maybe abort suspend? */
 143         if (irqd_is_wakeup_set(irq_get_irq_data(irq))) {
 144                 pm_wakeup_event(wirq->dev, 0);
 145
 146                 return IRQ_HANDLED;
 147         }
 148
 149         /* We don't want RPM_ASYNC or RPM_NOWAIT here */
 150         res = pm_runtime_resume(wirq->dev);
 151         if (res < 0)
 152                 dev_warn(wirq->dev,
 153                          "wake IRQ with no resume: %i\n", res);
 154
 155         return IRQ_HANDLED;
 156 }
 157
 158 /**
 159  * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
 160  * @dev: Device entry
 161  * @irq: Device wake-up interrupt
 162  *
 163  * Unless your hardware has separate wake-up interrupts in addition
 164  * to the device IO interrupts, you don't need this.
 165  *
 166  * Sets up a threaded interrupt handler for a device that has
 167  * a dedicated wake-up interrupt in addition to the device IO
 168  * interrupt.
 169  *
 170  * The interrupt starts disabled, and needs to be managed for
 171  * the device by the bus code or the device driver using
 172  * dev_pm_enable_wake_irq() and dev_pm_disable_wake_irq()
 173  * functions.
 174  */
 175 int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
 176 {
 177         struct wake_irq *wirq;
 178         int err;
 179
 180         if (irq < 0)
 181                 return -EINVAL;
 182
 183         wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
 184         if (!wirq)
 185                 return -ENOMEM;
 186
 187         wirq->dev = dev;
 188         wirq->irq = irq;
 189         irq_set_status_flags(irq, IRQ_NOAUTOEN);
 190
 191         /* Prevent deferred spurious wakeirqs with disable_irq_nosync() */
 192         irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY);
 193
 194         /*
 195          * Consumer device may need to power up and restore state
 196          * so we use a threaded irq.
 197          */
 198         err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
 199                                    IRQF_ONESHOT, dev_name(dev), wirq);
 200         if (err)
 201                 goto err_free;
 202
 203         err = dev_pm_attach_wake_irq(dev, irq, wirq);
 204         if (err)
 205                 goto err_free_irq;
 206
 207         wirq->status = WAKE_IRQ_DEDICATED_ALLOCATED;
 208
 209         return err;
 210
 211 err_free_irq:
 212         free_irq(irq, wirq);
 213 err_free:
 214         kfree(wirq);
 215
 216         return err;
 217 }
 218 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
 219
 220 /**
 221  * dev_pm_enable_wake_irq - Enable device wake-up interrupt
 222  * @dev: Device
 223  *
 224  * Optionally called from the bus code or the device driver for
 225  * runtime_resume() to override the PM runtime core managed wake-up
 226  * interrupt handling to enable the wake-up interrupt.
 227  *
 228  * Note that for runtime_suspend()) the wake-up interrupts
 229  * should be unconditionally enabled unlike for suspend()
 230  * that is conditional.
 231  */
 232 void dev_pm_enable_wake_irq(struct device *dev)
 233 {
 234         struct wake_irq *wirq = dev->power.wakeirq;
 235
 236         if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
 237                 enable_irq(wirq->irq);
 238 }
 239 EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
 240
 241 /**
 242  * dev_pm_disable_wake_irq - Disable device wake-up interrupt
 243  * @dev: Device
 244  *
 245  * Optionally called from the bus code or the device driver for
 246  * runtime_suspend() to override the PM runtime core managed wake-up
 247  * interrupt handling to disable the wake-up interrupt.
 248  */
 249 void dev_pm_disable_wake_irq(struct device *dev)
 250 {
 251         struct wake_irq *wirq = dev->power.wakeirq;
 252
 253         if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
 254                 disable_irq_nosync(wirq->irq);
 255 }
 256 EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
 257
 258 /**
 259  * dev_pm_enable_wake_irq_check - Checks and enables wake-up interrupt
 260  * @dev: Device
 261  * @can_change_status: Can change wake-up interrupt status
 262  *
 263  * Enables wakeirq conditionally. We need to enable wake-up interrupt
 264  * lazily on the first rpm_suspend(). This is needed as the consumer device
 265  * starts in RPM_SUSPENDED state, and the the first pm_runtime_get() would
 266  * otherwise try to disable already disabled wakeirq. The wake-up interrupt
 267  * starts disabled with IRQ_NOAUTOEN set.
 268  *
 269  * Should be only called from rpm_suspend() and rpm_resume() path.
 270  * Caller must hold &dev->power.lock to change wirq->status
 271  */
 272 void dev_pm_enable_wake_irq_check(struct device *dev,
 273                                   bool can_change_status)
 274 {
 275         struct wake_irq *wirq = dev->power.wakeirq;
 276
 277         if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
 278                 return;
 279
 280         if (likely(wirq->status & WAKE_IRQ_DEDICATED_MANAGED)) {
 281                 goto enable;
 282         } else if (can_change_status) {
 283                 wirq->status |= WAKE_IRQ_DEDICATED_MANAGED;
 284                 goto enable;
 285         }
 286
 287         return;
 288
 289 enable:
 290         enable_irq(wirq->irq);
 291 }
 292
 293 /**
 294  * dev_pm_disable_wake_irq_check - Checks and disables wake-up interrupt
 295  * @dev: Device
 296  *
 297  * Disables wake-up interrupt conditionally based on status.
 298  * Should be only called from rpm_suspend() and rpm_resume() path.
 299  */
 300 void dev_pm_disable_wake_irq_check(struct device *dev)
 301 {
 302         struct wake_irq *wirq = dev->power.wakeirq;
 303
 304         if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
 305                 return;
 306
 307         if (wirq->status & WAKE_IRQ_DEDICATED_MANAGED)
 308                 disable_irq_nosync(wirq->irq);
 309 }
 310
 311 /**
 312  * dev_pm_arm_wake_irq - Arm device wake-up
 313  * @wirq: Device wake-up interrupt
 314  *
 315  * Sets up the wake-up event conditionally based on the
 316  * device_may_wake().
 317  */
 318 void dev_pm_arm_wake_irq(struct wake_irq *wirq)
 319 {
 320         if (!wirq)
 321                 return;
 322
 323         if (device_may_wakeup(wirq->dev)) {
 324                 if (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED &&
 325                     !pm_runtime_status_suspended(wirq->dev))
 326                         enable_irq(wirq->irq);
 327
 328                 enable_irq_wake(wirq->irq);
 329         }
 330 }
 331
 332 /**
 333  * dev_pm_disarm_wake_irq - Disarm device wake-up
 334  * @wirq: Device wake-up interrupt
 335  *
 336  * Clears up the wake-up event conditionally based on the
 337  * device_may_wake().
 338  */
 339 void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
 340 {
 341         if (!wirq)
 342                 return;
 343
 344         if (device_may_wakeup(wirq->dev)) {
 345                 disable_irq_wake(wirq->irq);
 346
 347                 if (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED &&
 348                     !pm_runtime_status_suspended(wirq->dev))
 349                         disable_irq_nosync(wirq->irq);
 350         }
 351 }