xref: /openbmc/linux/drivers/base/power/wakeirq.c (revision abfbd895)
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->dedicated_irq)
114 		free_irq(wirq->irq, wirq);
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 	/* We don't want RPM_ASYNC or RPM_NOWAIT here */
143 	res = pm_runtime_resume(wirq->dev);
144 	if (res < 0)
145 		dev_warn(wirq->dev,
146 			 "wake IRQ with no resume: %i\n", res);
147 
148 	return IRQ_HANDLED;
149 }
150 
151 /**
152  * dev_pm_set_dedicated_wake_irq - Request a dedicated wake-up interrupt
153  * @dev: Device entry
154  * @irq: Device wake-up interrupt
155  *
156  * Unless your hardware has separate wake-up interrupts in addition
157  * to the device IO interrupts, you don't need this.
158  *
159  * Sets up a threaded interrupt handler for a device that has
160  * a dedicated wake-up interrupt in addition to the device IO
161  * interrupt.
162  *
163  * The interrupt starts disabled, and needs to be managed for
164  * the device by the bus code or the device driver using
165  * dev_pm_enable_wake_irq() and dev_pm_disable_wake_irq()
166  * functions.
167  */
168 int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
169 {
170 	struct wake_irq *wirq;
171 	int err;
172 
173 	if (irq < 0)
174 		return -EINVAL;
175 
176 	wirq = kzalloc(sizeof(*wirq), GFP_KERNEL);
177 	if (!wirq)
178 		return -ENOMEM;
179 
180 	wirq->dev = dev;
181 	wirq->irq = irq;
182 	wirq->dedicated_irq = true;
183 	irq_set_status_flags(irq, IRQ_NOAUTOEN);
184 
185 	/*
186 	 * Consumer device may need to power up and restore state
187 	 * so we use a threaded irq.
188 	 */
189 	err = request_threaded_irq(irq, NULL, handle_threaded_wake_irq,
190 				   IRQF_ONESHOT, dev_name(dev), wirq);
191 	if (err)
192 		goto err_free;
193 
194 	err = dev_pm_attach_wake_irq(dev, irq, wirq);
195 	if (err)
196 		goto err_free_irq;
197 
198 	return err;
199 
200 err_free_irq:
201 	free_irq(irq, wirq);
202 err_free:
203 	kfree(wirq);
204 
205 	return err;
206 }
207 EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
208 
209 /**
210  * dev_pm_enable_wake_irq - Enable device wake-up interrupt
211  * @dev: Device
212  *
213  * Called from the bus code or the device driver for
214  * runtime_suspend() to enable the wake-up interrupt while
215  * the device is running.
216  *
217  * Note that for runtime_suspend()) the wake-up interrupts
218  * should be unconditionally enabled unlike for suspend()
219  * that is conditional.
220  */
221 void dev_pm_enable_wake_irq(struct device *dev)
222 {
223 	struct wake_irq *wirq = dev->power.wakeirq;
224 
225 	if (wirq && wirq->dedicated_irq)
226 		enable_irq(wirq->irq);
227 }
228 EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
229 
230 /**
231  * dev_pm_disable_wake_irq - Disable device wake-up interrupt
232  * @dev: Device
233  *
234  * Called from the bus code or the device driver for
235  * runtime_resume() to disable the wake-up interrupt while
236  * the device is running.
237  */
238 void dev_pm_disable_wake_irq(struct device *dev)
239 {
240 	struct wake_irq *wirq = dev->power.wakeirq;
241 
242 	if (wirq && wirq->dedicated_irq)
243 		disable_irq_nosync(wirq->irq);
244 }
245 EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
246 
247 /**
248  * dev_pm_arm_wake_irq - Arm device wake-up
249  * @wirq: Device wake-up interrupt
250  *
251  * Sets up the wake-up event conditionally based on the
252  * device_may_wake().
253  */
254 void dev_pm_arm_wake_irq(struct wake_irq *wirq)
255 {
256 	if (!wirq)
257 		return;
258 
259 	if (device_may_wakeup(wirq->dev))
260 		enable_irq_wake(wirq->irq);
261 }
262 
263 /**
264  * dev_pm_disarm_wake_irq - Disarm device wake-up
265  * @wirq: Device wake-up interrupt
266  *
267  * Clears up the wake-up event conditionally based on the
268  * device_may_wake().
269  */
270 void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
271 {
272 	if (!wirq)
273 		return;
274 
275 	if (device_may_wakeup(wirq->dev))
276 		disable_irq_wake(wirq->irq);
277 }
278