xref: /openbmc/linux/drivers/scsi/scsi_pm.c (revision 05bcf503)
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 			if (err)
30 				scsi_device_resume(to_scsi_device(dev));
31 		}
32 	}
33 	dev_dbg(dev, "scsi suspend: %d\n", err);
34 	return err;
35 }
36 
37 static int scsi_dev_type_resume(struct device *dev)
38 {
39 	struct device_driver *drv;
40 	int err = 0;
41 
42 	drv = dev->driver;
43 	if (drv && drv->resume)
44 		err = drv->resume(dev);
45 	scsi_device_resume(to_scsi_device(dev));
46 	dev_dbg(dev, "scsi resume: %d\n", err);
47 	return err;
48 }
49 
50 #ifdef CONFIG_PM_SLEEP
51 
52 static int scsi_bus_suspend_common(struct device *dev, pm_message_t msg)
53 {
54 	int err = 0;
55 
56 	if (scsi_is_sdev_device(dev)) {
57 		/*
58 		 * sd is the only high-level SCSI driver to implement runtime
59 		 * PM, and sd treats runtime suspend, system suspend, and
60 		 * system hibernate identically (but not system freeze).
61 		 */
62 		if (pm_runtime_suspended(dev)) {
63 			if (msg.event == PM_EVENT_SUSPEND ||
64 			    msg.event == PM_EVENT_HIBERNATE)
65 				return 0;	/* already suspended */
66 
67 			/* wake up device so that FREEZE will succeed */
68 			pm_runtime_resume(dev);
69 		}
70 		err = scsi_dev_type_suspend(dev, msg);
71 	}
72 	return err;
73 }
74 
75 static int scsi_bus_resume_common(struct device *dev)
76 {
77 	int err = 0;
78 
79 	/*
80 	 * Parent device may have runtime suspended as soon as
81 	 * it is woken up during the system resume.
82 	 *
83 	 * Resume it on behalf of child.
84 	 */
85 	pm_runtime_get_sync(dev->parent);
86 
87 	if (scsi_is_sdev_device(dev))
88 		err = scsi_dev_type_resume(dev);
89 	if (err == 0) {
90 		pm_runtime_disable(dev);
91 		pm_runtime_set_active(dev);
92 		pm_runtime_enable(dev);
93 	}
94 
95 	pm_runtime_put_sync(dev->parent);
96 
97 	return err;
98 }
99 
100 static int scsi_bus_prepare(struct device *dev)
101 {
102 	if (scsi_is_sdev_device(dev)) {
103 		/* sd probing uses async_schedule.  Wait until it finishes. */
104 		async_synchronize_full_domain(&scsi_sd_probe_domain);
105 
106 	} else if (scsi_is_host_device(dev)) {
107 		/* Wait until async scanning is finished */
108 		scsi_complete_async_scans();
109 	}
110 	return 0;
111 }
112 
113 static int scsi_bus_suspend(struct device *dev)
114 {
115 	return scsi_bus_suspend_common(dev, PMSG_SUSPEND);
116 }
117 
118 static int scsi_bus_freeze(struct device *dev)
119 {
120 	return scsi_bus_suspend_common(dev, PMSG_FREEZE);
121 }
122 
123 static int scsi_bus_poweroff(struct device *dev)
124 {
125 	return scsi_bus_suspend_common(dev, PMSG_HIBERNATE);
126 }
127 
128 #else /* CONFIG_PM_SLEEP */
129 
130 #define scsi_bus_resume_common		NULL
131 #define scsi_bus_prepare		NULL
132 #define scsi_bus_suspend		NULL
133 #define scsi_bus_freeze			NULL
134 #define scsi_bus_poweroff		NULL
135 
136 #endif /* CONFIG_PM_SLEEP */
137 
138 #ifdef CONFIG_PM_RUNTIME
139 
140 static int scsi_runtime_suspend(struct device *dev)
141 {
142 	int err = 0;
143 
144 	dev_dbg(dev, "scsi_runtime_suspend\n");
145 	if (scsi_is_sdev_device(dev)) {
146 		err = scsi_dev_type_suspend(dev, PMSG_AUTO_SUSPEND);
147 		if (err == -EAGAIN)
148 			pm_schedule_suspend(dev, jiffies_to_msecs(
149 				round_jiffies_up_relative(HZ/10)));
150 	}
151 
152 	/* Insert hooks here for targets, hosts, and transport classes */
153 
154 	return err;
155 }
156 
157 static int scsi_runtime_resume(struct device *dev)
158 {
159 	int err = 0;
160 
161 	dev_dbg(dev, "scsi_runtime_resume\n");
162 	if (scsi_is_sdev_device(dev))
163 		err = scsi_dev_type_resume(dev);
164 
165 	/* Insert hooks here for targets, hosts, and transport classes */
166 
167 	return err;
168 }
169 
170 static int scsi_runtime_idle(struct device *dev)
171 {
172 	int err;
173 
174 	dev_dbg(dev, "scsi_runtime_idle\n");
175 
176 	/* Insert hooks here for targets, hosts, and transport classes */
177 
178 	if (scsi_is_sdev_device(dev))
179 		err = pm_schedule_suspend(dev, 100);
180 	else
181 		err = pm_runtime_suspend(dev);
182 	return err;
183 }
184 
185 int scsi_autopm_get_device(struct scsi_device *sdev)
186 {
187 	int	err;
188 
189 	err = pm_runtime_get_sync(&sdev->sdev_gendev);
190 	if (err < 0 && err !=-EACCES)
191 		pm_runtime_put_sync(&sdev->sdev_gendev);
192 	else
193 		err = 0;
194 	return err;
195 }
196 EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
197 
198 void scsi_autopm_put_device(struct scsi_device *sdev)
199 {
200 	pm_runtime_put_sync(&sdev->sdev_gendev);
201 }
202 EXPORT_SYMBOL_GPL(scsi_autopm_put_device);
203 
204 void scsi_autopm_get_target(struct scsi_target *starget)
205 {
206 	pm_runtime_get_sync(&starget->dev);
207 }
208 
209 void scsi_autopm_put_target(struct scsi_target *starget)
210 {
211 	pm_runtime_put_sync(&starget->dev);
212 }
213 
214 int scsi_autopm_get_host(struct Scsi_Host *shost)
215 {
216 	int	err;
217 
218 	err = pm_runtime_get_sync(&shost->shost_gendev);
219 	if (err < 0 && err !=-EACCES)
220 		pm_runtime_put_sync(&shost->shost_gendev);
221 	else
222 		err = 0;
223 	return err;
224 }
225 
226 void scsi_autopm_put_host(struct Scsi_Host *shost)
227 {
228 	pm_runtime_put_sync(&shost->shost_gendev);
229 }
230 
231 #else
232 
233 #define scsi_runtime_suspend	NULL
234 #define scsi_runtime_resume	NULL
235 #define scsi_runtime_idle	NULL
236 
237 #endif /* CONFIG_PM_RUNTIME */
238 
239 const struct dev_pm_ops scsi_bus_pm_ops = {
240 	.prepare =		scsi_bus_prepare,
241 	.suspend =		scsi_bus_suspend,
242 	.resume =		scsi_bus_resume_common,
243 	.freeze =		scsi_bus_freeze,
244 	.thaw =			scsi_bus_resume_common,
245 	.poweroff =		scsi_bus_poweroff,
246 	.restore =		scsi_bus_resume_common,
247 	.runtime_suspend =	scsi_runtime_suspend,
248 	.runtime_resume =	scsi_runtime_resume,
249 	.runtime_idle =		scsi_runtime_idle,
250 };
251