drivers/scsi/scsi_pm.c

   1 /*
   2  *      scsi_pm.c       Copyright (C) 2010 Alan Stern
   3  *
   4  *      SCSI dynamic Power Management
   5  *              Initial version: Alan Stern <stern@rowland.harvard.edu>
   6  */
   7
   8 #include <linux/pm_runtime.h>
   9 #include <linux/export.h>
  10 #include <linux/async.h>
  11
  12 #include <scsi/scsi.h>
  13 #include <scsi/scsi_device.h>
  14 #include <scsi/scsi_driver.h>
  15 #include <scsi/scsi_host.h>
  16
  17 #include "scsi_priv.h"
  18
  19 static int scsi_dev_type_suspend(struct device *dev, pm_message_t msg)
  20 {
  21         struct device_driver *drv;
  22         int err;
  23
  24         err = scsi_device_quiesce(to_scsi_device(dev));
  25         if (err == 0) {
  26                 drv = dev->driver;
  27                 if (drv && drv->suspend)
  28                         err = drv->suspend(dev, msg);
  29         }
  30         dev_dbg(dev, "scsi suspend: %d\n", err);
  31         return err;
  32 }
  33
  34 static int scsi_dev_type_resume(struct device *dev)
  35 {
  36         struct device_driver *drv;
  37         int err = 0;
  38
  39         drv = dev->driver;
  40         if (drv && drv->resume)
  41                 err = drv->resume(dev);
  42         scsi_device_resume(to_scsi_device(dev));
  43         dev_dbg(dev, "scsi resume: %d\n", err);
  44         return err;
  45 }
  46
  47 #ifdef CONFIG_PM_SLEEP
  48
  49 static int scsi_bus_suspend_common(struct device *dev, pm_message_t msg)
  50 {
  51         int err = 0;
  52
  53         if (scsi_is_sdev_device(dev)) {
  54                 /*
  55                  * sd is the only high-level SCSI driver to implement runtime
  56                  * PM, and sd treats runtime suspend, system suspend, and
  57                  * system hibernate identically (but not system freeze).
  58                  */
  59                 if (pm_runtime_suspended(dev)) {
  60                         if (msg.event == PM_EVENT_SUSPEND ||
  61                             msg.event == PM_EVENT_HIBERNATE)
  62                                 return 0;       /* already suspended */
  63
  64                         /* wake up device so that FREEZE will succeed */
  65                         pm_runtime_resume(dev);
  66                 }
  67                 err = scsi_dev_type_suspend(dev, msg);
  68         }
  69         return err;
  70 }
  71
  72 static int scsi_bus_resume_common(struct device *dev)
  73 {
  74         int err = 0;
  75
  76         if (scsi_is_sdev_device(dev)) {
  77                 /*
  78                  * Parent device may have runtime suspended as soon as
  79                  * it is woken up during the system resume.
  80                  *
  81                  * Resume it on behalf of child.
  82                  */
  83                 pm_runtime_get_sync(dev->parent);
  84                 err = scsi_dev_type_resume(dev);
  85                 pm_runtime_put_sync(dev->parent);
  86         }
  87
  88         if (err == 0) {
  89                 pm_runtime_disable(dev);
  90                 pm_runtime_set_active(dev);
  91                 pm_runtime_enable(dev);
  92         }
  93         return err;
  94 }
  95
  96 static int scsi_bus_prepare(struct device *dev)
  97 {
  98         if (scsi_is_sdev_device(dev)) {
  99                 /* sd probing uses async_schedule.  Wait until it finishes. */
 100                 async_synchronize_full();
 101
 102         } else if (scsi_is_host_device(dev)) {
 103                 /* Wait until async scanning is finished */
 104                 scsi_complete_async_scans();
 105         }
 106         return 0;
 107 }
 108
 109 static int scsi_bus_suspend(struct device *dev)
 110 {
 111         return scsi_bus_suspend_common(dev, PMSG_SUSPEND);
 112 }
 113
 114 static int scsi_bus_freeze(struct device *dev)
 115 {
 116         return scsi_bus_suspend_common(dev, PMSG_FREEZE);
 117 }
 118
 119 static int scsi_bus_poweroff(struct device *dev)
 120 {
 121         return scsi_bus_suspend_common(dev, PMSG_HIBERNATE);
 122 }
 123
 124 #else /* CONFIG_PM_SLEEP */
 125
 126 #define scsi_bus_resume_common          NULL
 127 #define scsi_bus_prepare                NULL
 128 #define scsi_bus_suspend                NULL
 129 #define scsi_bus_freeze                 NULL
 130 #define scsi_bus_poweroff               NULL
 131
 132 #endif /* CONFIG_PM_SLEEP */
 133
 134 #ifdef CONFIG_PM_RUNTIME
 135
 136 static int scsi_runtime_suspend(struct device *dev)
 137 {
 138         int err = 0;
 139
 140         dev_dbg(dev, "scsi_runtime_suspend\n");
 141         if (scsi_is_sdev_device(dev)) {
 142                 err = scsi_dev_type_suspend(dev, PMSG_AUTO_SUSPEND);
 143                 if (err == -EAGAIN)
 144                         pm_schedule_suspend(dev, jiffies_to_msecs(
 145                                 round_jiffies_up_relative(HZ/10)));
 146         }
 147
 148         /* Insert hooks here for targets, hosts, and transport classes */
 149
 150         return err;
 151 }
 152
 153 static int scsi_runtime_resume(struct device *dev)
 154 {
 155         int err = 0;
 156
 157         dev_dbg(dev, "scsi_runtime_resume\n");
 158         if (scsi_is_sdev_device(dev))
 159                 err = scsi_dev_type_resume(dev);
 160
 161         /* Insert hooks here for targets, hosts, and transport classes */
 162
 163         return err;
 164 }
 165
 166 static int scsi_runtime_idle(struct device *dev)
 167 {
 168         int err;
 169
 170         dev_dbg(dev, "scsi_runtime_idle\n");
 171
 172         /* Insert hooks here for targets, hosts, and transport classes */
 173
 174         if (scsi_is_sdev_device(dev))
 175                 err = pm_schedule_suspend(dev, 100);
 176         else
 177                 err = pm_runtime_suspend(dev);
 178         return err;
 179 }
 180
 181 int scsi_autopm_get_device(struct scsi_device *sdev)
 182 {
 183         int     err;
 184
 185         err = pm_runtime_get_sync(&sdev->sdev_gendev);
 186         if (err < 0 && err !=-EACCES)
 187                 pm_runtime_put_sync(&sdev->sdev_gendev);
 188         else
 189                 err = 0;
 190         return err;
 191 }
 192 EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
 193
 194 void scsi_autopm_put_device(struct scsi_device *sdev)
 195 {
 196         pm_runtime_put_sync(&sdev->sdev_gendev);
 197 }
 198 EXPORT_SYMBOL_GPL(scsi_autopm_put_device);
 199
 200 void scsi_autopm_get_target(struct scsi_target *starget)
 201 {
 202         pm_runtime_get_sync(&starget->dev);
 203 }
 204
 205 void scsi_autopm_put_target(struct scsi_target *starget)
 206 {
 207         pm_runtime_put_sync(&starget->dev);
 208 }
 209
 210 int scsi_autopm_get_host(struct Scsi_Host *shost)
 211 {
 212         int     err;
 213
 214         err = pm_runtime_get_sync(&shost->shost_gendev);
 215         if (err < 0 && err !=-EACCES)
 216                 pm_runtime_put_sync(&shost->shost_gendev);
 217         else
 218                 err = 0;
 219         return err;
 220 }
 221
 222 void scsi_autopm_put_host(struct Scsi_Host *shost)
 223 {
 224         pm_runtime_put_sync(&shost->shost_gendev);
 225 }
 226
 227 #else
 228
 229 #define scsi_runtime_suspend    NULL
 230 #define scsi_runtime_resume     NULL
 231 #define scsi_runtime_idle       NULL
 232
 233 #endif /* CONFIG_PM_RUNTIME */
 234
 235 const struct dev_pm_ops scsi_bus_pm_ops = {
 236         .prepare =              scsi_bus_prepare,
 237         .suspend =              scsi_bus_suspend,
 238         .resume =               scsi_bus_resume_common,
 239         .freeze =               scsi_bus_freeze,
 240         .thaw =                 scsi_bus_resume_common,
 241         .poweroff =             scsi_bus_poweroff,
 242         .restore =              scsi_bus_resume_common,
 243         .runtime_suspend =      scsi_runtime_suspend,
 244         .runtime_resume =       scsi_runtime_resume,
 245         .runtime_idle =         scsi_runtime_idle,
 246 };