1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * The driver-specific portions of the driver model
4  *
5  * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
6  * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
7  * Copyright (c) 2008-2009 Novell Inc.
8  * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
9  * Copyright (c) 2012-2019 Linux Foundation
10  *
11  * See Documentation/driver-api/driver-model/ for more information.
12  */
13 
14 #ifndef _DEVICE_DRIVER_H_
15 #define _DEVICE_DRIVER_H_
16 
17 #include <linux/kobject.h>
18 #include <linux/klist.h>
19 #include <linux/pm.h>
20 #include <linux/device/bus.h>
21 #include <linux/module.h>
22 
23 /**
24  * enum probe_type - device driver probe type to try
25  *	Device drivers may opt in for special handling of their
26  *	respective probe routines. This tells the core what to
27  *	expect and prefer.
28  *
29  * @PROBE_DEFAULT_STRATEGY: Used by drivers that work equally well
30  *	whether probed synchronously or asynchronously.
31  * @PROBE_PREFER_ASYNCHRONOUS: Drivers for "slow" devices which
32  *	probing order is not essential for booting the system may
33  *	opt into executing their probes asynchronously.
34  * @PROBE_FORCE_SYNCHRONOUS: Use this to annotate drivers that need
35  *	their probe routines to run synchronously with driver and
36  *	device registration (with the exception of -EPROBE_DEFER
37  *	handling - re-probing always ends up being done asynchronously).
38  *
39  * Note that the end goal is to switch the kernel to use asynchronous
40  * probing by default, so annotating drivers with
41  * %PROBE_PREFER_ASYNCHRONOUS is a temporary measure that allows us
42  * to speed up boot process while we are validating the rest of the
43  * drivers.
44  */
45 enum probe_type {
46 	PROBE_DEFAULT_STRATEGY,
47 	PROBE_PREFER_ASYNCHRONOUS,
48 	PROBE_FORCE_SYNCHRONOUS,
49 };
50 
51 /**
52  * struct device_driver - The basic device driver structure
53  * @name:	Name of the device driver.
54  * @bus:	The bus which the device of this driver belongs to.
55  * @owner:	The module owner.
56  * @mod_name:	Used for built-in modules.
57  * @suppress_bind_attrs: Disables bind/unbind via sysfs.
58  * @probe_type:	Type of the probe (synchronous or asynchronous) to use.
59  * @of_match_table: The open firmware table.
60  * @acpi_match_table: The ACPI match table.
61  * @probe:	Called to query the existence of a specific device,
62  *		whether this driver can work with it, and bind the driver
63  *		to a specific device.
64  * @sync_state:	Called to sync device state to software state after all the
65  *		state tracking consumers linked to this device (present at
66  *		the time of late_initcall) have successfully bound to a
67  *		driver. If the device has no consumers, this function will
68  *		be called at late_initcall_sync level. If the device has
69  *		consumers that are never bound to a driver, this function
70  *		will never get called until they do.
71  * @remove:	Called when the device is removed from the system to
72  *		unbind a device from this driver.
73  * @shutdown:	Called at shut-down time to quiesce the device.
74  * @suspend:	Called to put the device to sleep mode. Usually to a
75  *		low power state.
76  * @resume:	Called to bring a device from sleep mode.
77  * @groups:	Default attributes that get created by the driver core
78  *		automatically.
79  * @dev_groups:	Additional attributes attached to device instance once
80  *		it is bound to the driver.
81  * @pm:		Power management operations of the device which matched
82  *		this driver.
83  * @coredump:	Called when sysfs entry is written to. The device driver
84  *		is expected to call the dev_coredump API resulting in a
85  *		uevent.
86  * @p:		Driver core's private data, no one other than the driver
87  *		core can touch this.
88  *
89  * The device driver-model tracks all of the drivers known to the system.
90  * The main reason for this tracking is to enable the driver core to match
91  * up drivers with new devices. Once drivers are known objects within the
92  * system, however, a number of other things become possible. Device drivers
93  * can export information and configuration variables that are independent
94  * of any specific device.
95  */
96 struct device_driver {
97 	const char		*name;
98 	const struct bus_type	*bus;
99 
100 	struct module		*owner;
101 	const char		*mod_name;	/* used for built-in modules */
102 
103 	bool suppress_bind_attrs;	/* disables bind/unbind via sysfs */
104 	enum probe_type probe_type;
105 
106 	const struct of_device_id	*of_match_table;
107 	const struct acpi_device_id	*acpi_match_table;
108 
109 	int (*probe) (struct device *dev);
110 	void (*sync_state)(struct device *dev);
111 	int (*remove) (struct device *dev);
112 	void (*shutdown) (struct device *dev);
113 	int (*suspend) (struct device *dev, pm_message_t state);
114 	int (*resume) (struct device *dev);
115 	const struct attribute_group **groups;
116 	const struct attribute_group **dev_groups;
117 
118 	const struct dev_pm_ops *pm;
119 	void (*coredump) (struct device *dev);
120 
121 	struct driver_private *p;
122 };
123 
124 
125 int __must_check driver_register(struct device_driver *drv);
126 void driver_unregister(struct device_driver *drv);
127 
128 struct device_driver *driver_find(const char *name, const struct bus_type *bus);
129 bool __init driver_probe_done(void);
130 void wait_for_device_probe(void);
131 void __init wait_for_init_devices_probe(void);
132 
133 /* sysfs interface for exporting driver attributes */
134 
135 struct driver_attribute {
136 	struct attribute attr;
137 	ssize_t (*show)(struct device_driver *driver, char *buf);
138 	ssize_t (*store)(struct device_driver *driver, const char *buf,
139 			 size_t count);
140 };
141 
142 #define DRIVER_ATTR_RW(_name) \
143 	struct driver_attribute driver_attr_##_name = __ATTR_RW(_name)
144 #define DRIVER_ATTR_RO(_name) \
145 	struct driver_attribute driver_attr_##_name = __ATTR_RO(_name)
146 #define DRIVER_ATTR_WO(_name) \
147 	struct driver_attribute driver_attr_##_name = __ATTR_WO(_name)
148 
149 int __must_check driver_create_file(struct device_driver *driver,
150 				    const struct driver_attribute *attr);
151 void driver_remove_file(struct device_driver *driver,
152 			const struct driver_attribute *attr);
153 
154 int driver_set_override(struct device *dev, const char **override,
155 			const char *s, size_t len);
156 int __must_check driver_for_each_device(struct device_driver *drv, struct device *start,
157 					void *data, int (*fn)(struct device *dev, void *));
158 struct device *driver_find_device(struct device_driver *drv,
159 				  struct device *start, const void *data,
160 				  int (*match)(struct device *dev, const void *data));
161 
162 /**
163  * driver_find_device_by_name - device iterator for locating a particular device
164  * of a specific name.
165  * @drv: the driver we're iterating
166  * @name: name of the device to match
167  */
driver_find_device_by_name(struct device_driver * drv,const char * name)168 static inline struct device *driver_find_device_by_name(struct device_driver *drv,
169 							const char *name)
170 {
171 	return driver_find_device(drv, NULL, name, device_match_name);
172 }
173 
174 /**
175  * driver_find_device_by_of_node- device iterator for locating a particular device
176  * by of_node pointer.
177  * @drv: the driver we're iterating
178  * @np: of_node pointer to match.
179  */
180 static inline struct device *
driver_find_device_by_of_node(struct device_driver * drv,const struct device_node * np)181 driver_find_device_by_of_node(struct device_driver *drv,
182 			      const struct device_node *np)
183 {
184 	return driver_find_device(drv, NULL, np, device_match_of_node);
185 }
186 
187 /**
188  * driver_find_device_by_fwnode- device iterator for locating a particular device
189  * by fwnode pointer.
190  * @drv: the driver we're iterating
191  * @fwnode: fwnode pointer to match.
192  */
193 static inline struct device *
driver_find_device_by_fwnode(struct device_driver * drv,const struct fwnode_handle * fwnode)194 driver_find_device_by_fwnode(struct device_driver *drv,
195 			     const struct fwnode_handle *fwnode)
196 {
197 	return driver_find_device(drv, NULL, fwnode, device_match_fwnode);
198 }
199 
200 /**
201  * driver_find_device_by_devt- device iterator for locating a particular device
202  * by devt.
203  * @drv: the driver we're iterating
204  * @devt: devt pointer to match.
205  */
driver_find_device_by_devt(struct device_driver * drv,dev_t devt)206 static inline struct device *driver_find_device_by_devt(struct device_driver *drv,
207 							dev_t devt)
208 {
209 	return driver_find_device(drv, NULL, &devt, device_match_devt);
210 }
211 
driver_find_next_device(struct device_driver * drv,struct device * start)212 static inline struct device *driver_find_next_device(struct device_driver *drv,
213 						     struct device *start)
214 {
215 	return driver_find_device(drv, start, NULL, device_match_any);
216 }
217 
218 #ifdef CONFIG_ACPI
219 /**
220  * driver_find_device_by_acpi_dev : device iterator for locating a particular
221  * device matching the ACPI_COMPANION device.
222  * @drv: the driver we're iterating
223  * @adev: ACPI_COMPANION device to match.
224  */
225 static inline struct device *
driver_find_device_by_acpi_dev(struct device_driver * drv,const struct acpi_device * adev)226 driver_find_device_by_acpi_dev(struct device_driver *drv,
227 			       const struct acpi_device *adev)
228 {
229 	return driver_find_device(drv, NULL, adev, device_match_acpi_dev);
230 }
231 #else
232 static inline struct device *
driver_find_device_by_acpi_dev(struct device_driver * drv,const void * adev)233 driver_find_device_by_acpi_dev(struct device_driver *drv, const void *adev)
234 {
235 	return NULL;
236 }
237 #endif
238 
239 void driver_deferred_probe_add(struct device *dev);
240 int driver_deferred_probe_check_state(struct device *dev);
241 void driver_init(void);
242 
243 /**
244  * module_driver() - Helper macro for drivers that don't do anything
245  * special in module init/exit. This eliminates a lot of boilerplate.
246  * Each module may only use this macro once, and calling it replaces
247  * module_init() and module_exit().
248  *
249  * @__driver: driver name
250  * @__register: register function for this driver type
251  * @__unregister: unregister function for this driver type
252  * @...: Additional arguments to be passed to __register and __unregister.
253  *
254  * Use this macro to construct bus specific macros for registering
255  * drivers, and do not use it on its own.
256  */
257 #define module_driver(__driver, __register, __unregister, ...) \
258 static int __init __driver##_init(void) \
259 { \
260 	return __register(&(__driver) , ##__VA_ARGS__); \
261 } \
262 module_init(__driver##_init); \
263 static void __exit __driver##_exit(void) \
264 { \
265 	__unregister(&(__driver) , ##__VA_ARGS__); \
266 } \
267 module_exit(__driver##_exit);
268 
269 /**
270  * builtin_driver() - Helper macro for drivers that don't do anything
271  * special in init and have no exit. This eliminates some boilerplate.
272  * Each driver may only use this macro once, and calling it replaces
273  * device_initcall (or in some cases, the legacy __initcall).  This is
274  * meant to be a direct parallel of module_driver() above but without
275  * the __exit stuff that is not used for builtin cases.
276  *
277  * @__driver: driver name
278  * @__register: register function for this driver type
279  * @...: Additional arguments to be passed to __register
280  *
281  * Use this macro to construct bus specific macros for registering
282  * drivers, and do not use it on its own.
283  */
284 #define builtin_driver(__driver, __register, ...) \
285 static int __init __driver##_init(void) \
286 { \
287 	return __register(&(__driver) , ##__VA_ARGS__); \
288 } \
289 device_initcall(__driver##_init);
290 
291 #endif	/* _DEVICE_DRIVER_H_ */
292