[mirror_ubuntu-hirsute-kernel.git] / drivers / base / auxiliary.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2019-2020 Intel Corporation
 *
 * Please see Documentation/driver-api/auxiliary_bus.rst for more information.
 */

#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__

#include <linux/device.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/string.h>
#include <linux/auxiliary_bus.h>

static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id,
							    const struct auxiliary_device *auxdev)
{
	for (; id->name[0]; id++) {
		const char *p = strrchr(dev_name(&auxdev->dev), '.');
		int match_size;

		if (!p)
			continue;
		match_size = p - dev_name(&auxdev->dev);

		/* use dev_name(&auxdev->dev) prefix before last '.' char to match to */
		if (strlen(id->name) == match_size &&
		    !strncmp(dev_name(&auxdev->dev), id->name, match_size))
			return id;
	}
	return NULL;
}

static int auxiliary_match(struct device *dev, struct device_driver *drv)
{
	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
	struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);

	return !!auxiliary_match_id(auxdrv->id_table, auxdev);
}

static int auxiliary_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	const char *name, *p;

	name = dev_name(dev);
	p = strrchr(name, '.');

	return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
			      (int)(p - name), name);
}

static const struct dev_pm_ops auxiliary_dev_pm_ops = {
	SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL)
	SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
};

static int auxiliary_bus_probe(struct device *dev)
{
	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
	int ret;

	ret = dev_pm_domain_attach(dev, true);
	if (ret) {
		dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret);
		return ret;
	}

	ret = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev));
	if (ret)
		dev_pm_domain_detach(dev, true);

	return ret;
}

static int auxiliary_bus_remove(struct device *dev)
{
	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);

	if (auxdrv->remove)
		auxdrv->remove(auxdev);
	dev_pm_domain_detach(dev, true);

	return 0;
}

static void auxiliary_bus_shutdown(struct device *dev)
{
	struct auxiliary_driver *auxdrv = NULL;
	struct auxiliary_device *auxdev;

	if (dev->driver) {
		auxdrv = to_auxiliary_drv(dev->driver);
		auxdev = to_auxiliary_dev(dev);
	}

	if (auxdrv && auxdrv->shutdown)
		auxdrv->shutdown(auxdev);
}

static struct bus_type auxiliary_bus_type = {
	.name = "auxiliary",
	.probe = auxiliary_bus_probe,
	.remove = auxiliary_bus_remove,
	.shutdown = auxiliary_bus_shutdown,
	.match = auxiliary_match,
	.uevent = auxiliary_uevent,
	.pm = &auxiliary_dev_pm_ops,
};

/**
 * auxiliary_device_init - check auxiliary_device and initialize
 * @auxdev: auxiliary device struct
 *
 * This is the first step in the two-step process to register an
 * auxiliary_device.
 *
 * When this function returns an error code, then the device_initialize will
 * *not* have been performed, and the caller will be responsible to free any
 * memory allocated for the auxiliary_device in the error path directly.
 *
 * It returns 0 on success.  On success, the device_initialize has been
 * performed.  After this point any error unwinding will need to include a call
 * to auxiliary_device_uninit().  In this post-initialize error scenario, a call
 * to the device's .release callback will be triggered, and all memory clean-up
 * is expected to be handled there.
 */
int auxiliary_device_init(struct auxiliary_device *auxdev)
{
	struct device *dev = &auxdev->dev;

	if (!dev->parent) {
		pr_err("auxiliary_device has a NULL dev->parent\n");
		return -EINVAL;
	}

	if (!auxdev->name) {
		pr_err("auxiliary_device has a NULL name\n");
		return -EINVAL;
	}

	dev->bus = &auxiliary_bus_type;
	device_initialize(&auxdev->dev);
	return 0;
}
EXPORT_SYMBOL_GPL(auxiliary_device_init);

/**
 * __auxiliary_device_add - add an auxiliary bus device
 * @auxdev: auxiliary bus device to add to the bus
 * @modname: name of the parent device's driver module
 *
 * This is the second step in the two-step process to register an
 * auxiliary_device.
 *
 * This function must be called after a successful call to
 * auxiliary_device_init(), which will perform the device_initialize.  This
 * means that if this returns an error code, then a call to
 * auxiliary_device_uninit() must be performed so that the .release callback
 * will be triggered to free the memory associated with the auxiliary_device.
 *
 * The expectation is that users will call the "auxiliary_device_add" macro so
 * that the caller's KBUILD_MODNAME is automatically inserted for the modname
 * parameter.  Only if a user requires a custom name would this version be
 * called directly.
 */
int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname)
{
	struct device *dev = &auxdev->dev;
	int ret;

	if (!modname) {
		dev_err(dev, "auxiliary device modname is NULL\n");
		return -EINVAL;
	}

	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
	if (ret) {
		dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
		return ret;
	}

	ret = device_add(dev);
	if (ret)
		dev_err(dev, "adding auxiliary device failed!: %d\n", ret);

	return ret;
}
EXPORT_SYMBOL_GPL(__auxiliary_device_add);

/**
 * auxiliary_find_device - auxiliary device iterator for locating a particular device.
 * @start: Device to begin with
 * @data: Data to pass to match function
 * @match: Callback function to check device
 *
 * This function returns a reference to a device that is 'found'
 * for later use, as determined by the @match callback.
 *
 * The callback should return 0 if the device doesn't match and non-zero
 * if it does.  If the callback returns non-zero, this function will
 * return to the caller and not iterate over any more devices.
 */
struct auxiliary_device *auxiliary_find_device(struct device *start,
					       const void *data,
					       int (*match)(struct device *dev, const void *data))
{
	struct device *dev;

	dev = bus_find_device(&auxiliary_bus_type, start, data, match);
	if (!dev)
		return NULL;

	return to_auxiliary_dev(dev);
}
EXPORT_SYMBOL_GPL(auxiliary_find_device);

/**
 * __auxiliary_driver_register - register a driver for auxiliary bus devices
 * @auxdrv: auxiliary_driver structure
 * @owner: owning module/driver
 * @modname: KBUILD_MODNAME for parent driver
 */
int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
				struct module *owner, const char *modname)
{
	if (WARN_ON(!auxdrv->probe) || WARN_ON(!auxdrv->id_table))
		return -EINVAL;

	if (auxdrv->name)
		auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
						auxdrv->name);
	else
		auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
	if (!auxdrv->driver.name)
		return -ENOMEM;

	auxdrv->driver.owner = owner;
	auxdrv->driver.bus = &auxiliary_bus_type;
	auxdrv->driver.mod_name = modname;

	return driver_register(&auxdrv->driver);
}
EXPORT_SYMBOL_GPL(__auxiliary_driver_register);

/**
 * auxiliary_driver_unregister - unregister a driver
 * @auxdrv: auxiliary_driver structure
 */
void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
{
	driver_unregister(&auxdrv->driver);
	kfree(auxdrv->driver.name);
}
EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);

static int __init auxiliary_bus_init(void)
{
	return bus_register(&auxiliary_bus_type);
}

static void __exit auxiliary_bus_exit(void)
{
	bus_unregister(&auxiliary_bus_type);
}

module_init(auxiliary_bus_init);
module_exit(auxiliary_bus_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Auxiliary Bus");
MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>");
MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>");
Commit	Line	Data
7de3697e DE	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (c) 2019-2020 Intel Corporation
	4	*
	5	* Please see Documentation/driver-api/auxiliary_bus.rst for more information.
	6	*/
	7
	8	#define pr_fmt(fmt) "%s:%s: " fmt, KBUILD_MODNAME, __func__
	9
	10	#include <linux/device.h>
	11	#include <linux/init.h>
7bbb79ff	12	#include <linux/slab.h>
7de3697e DE	13	#include <linux/module.h>
	14	#include <linux/pm_domain.h>
	15	#include <linux/pm_runtime.h>
	16	#include <linux/string.h>
	17	#include <linux/auxiliary_bus.h>
	18
	19	static const struct auxiliary_device_id auxiliary_match_id(const struct auxiliary_device_id id,
	20	const struct auxiliary_device *auxdev)
	21	{
	22	for (; id->name[0]; id++) {
	23	const char *p = strrchr(dev_name(&auxdev->dev), '.');
	24	int match_size;
	25
	26	if (!p)
	27	continue;
	28	match_size = p - dev_name(&auxdev->dev);
	29
	30	/* use dev_name(&auxdev->dev) prefix before last '.' char to match to */
	31	if (strlen(id->name) == match_size &&
	32	!strncmp(dev_name(&auxdev->dev), id->name, match_size))
	33	return id;
	34	}
	35	return NULL;
	36	}
	37
	38	static int auxiliary_match(struct device dev, struct device_driver drv)
	39	{
	40	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
	41	struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);
	42
	43	return !!auxiliary_match_id(auxdrv->id_table, auxdev);
	44	}
	45
	46	static int auxiliary_uevent(struct device dev, struct kobj_uevent_env env)
	47	{
	48	const char name, p;
	49
	50	name = dev_name(dev);
	51	p = strrchr(name, '.');
	52
0d2bf11a GKH	53	return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
0d2bf11a GKH	54	(int)(p - name), name);
7de3697e DE	55	}
	56
	57	static const struct dev_pm_ops auxiliary_dev_pm_ops = {
	58	SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL)
	59	SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)
	60	};
	61
	62	static int auxiliary_bus_probe(struct device *dev)
	63	{
	64	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
	65	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
	66	int ret;
	67
	68	ret = dev_pm_domain_attach(dev, true);
	69	if (ret) {
	70	dev_warn(dev, "Failed to attach to PM Domain : %d\n", ret);
	71	return ret;
	72	}
	73
	74	ret = auxdrv->probe(auxdev, auxiliary_match_id(auxdrv->id_table, auxdev));
	75	if (ret)
	76	dev_pm_domain_detach(dev, true);
	77
	78	return ret;
	79	}
	80
	81	static int auxiliary_bus_remove(struct device *dev)
	82	{
	83	struct auxiliary_driver *auxdrv = to_auxiliary_drv(dev->driver);
	84	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
7de3697e DE	85
7de3697e DE	86	if (auxdrv->remove)
8142a46c	87	auxdrv->remove(auxdev);
7de3697e DE	88	dev_pm_domain_detach(dev, true);
7de3697e DE	89
8142a46c	90	return 0;
7de3697e DE	91	}
	92
	93	static void auxiliary_bus_shutdown(struct device *dev)
	94	{
784b2c48 DJ	95	struct auxiliary_driver *auxdrv = NULL;
	96	struct auxiliary_device *auxdev;
	97
	98	if (dev->driver) {
	99	auxdrv = to_auxiliary_drv(dev->driver);
	100	auxdev = to_auxiliary_dev(dev);
	101	}
7de3697e	102
784b2c48	103	if (auxdrv && auxdrv->shutdown)
7de3697e DE	104	auxdrv->shutdown(auxdev);
	105	}
	106
	107	static struct bus_type auxiliary_bus_type = {
	108	.name = "auxiliary",
	109	.probe = auxiliary_bus_probe,
	110	.remove = auxiliary_bus_remove,
	111	.shutdown = auxiliary_bus_shutdown,
	112	.match = auxiliary_match,
	113	.uevent = auxiliary_uevent,
	114	.pm = &auxiliary_dev_pm_ops,
	115	};
	116
	117	/**
	118	* auxiliary_device_init - check auxiliary_device and initialize
	119	* @auxdev: auxiliary device struct
	120	*
0d2bf11a GKH	121	* This is the first step in the two-step process to register an
0d2bf11a GKH	122	* auxiliary_device.
7de3697e	123	*
0d2bf11a GKH	124	* When this function returns an error code, then the device_initialize will
	125	* not have been performed, and the caller will be responsible to free any
	126	* memory allocated for the auxiliary_device in the error path directly.
7de3697e	127	*
0d2bf11a GKH	128	* It returns 0 on success. On success, the device_initialize has been
	129	* performed. After this point any error unwinding will need to include a call
	130	* to auxiliary_device_uninit(). In this post-initialize error scenario, a call
	131	* to the device's .release callback will be triggered, and all memory clean-up
	132	* is expected to be handled there.
7de3697e DE	133	*/
	134	int auxiliary_device_init(struct auxiliary_device *auxdev)
	135	{
	136	struct device *dev = &auxdev->dev;
	137
	138	if (!dev->parent) {
	139	pr_err("auxiliary_device has a NULL dev->parent\n");
	140	return -EINVAL;
	141	}
	142
	143	if (!auxdev->name) {
	144	pr_err("auxiliary_device has a NULL name\n");
	145	return -EINVAL;
	146	}
	147
	148	dev->bus = &auxiliary_bus_type;
	149	device_initialize(&auxdev->dev);
	150	return 0;
	151	}
	152	EXPORT_SYMBOL_GPL(auxiliary_device_init);
	153
	154	/**
	155	* __auxiliary_device_add - add an auxiliary bus device
	156	* @auxdev: auxiliary bus device to add to the bus
	157	* @modname: name of the parent device's driver module
	158	*
0d2bf11a GKH	159	* This is the second step in the two-step process to register an
0d2bf11a GKH	160	* auxiliary_device.
7de3697e	161	*
0d2bf11a GKH	162	* This function must be called after a successful call to
	163	* auxiliary_device_init(), which will perform the device_initialize. This
	164	* means that if this returns an error code, then a call to
	165	* auxiliary_device_uninit() must be performed so that the .release callback
	166	* will be triggered to free the memory associated with the auxiliary_device.
7de3697e	167	*
0d2bf11a GKH	168	* The expectation is that users will call the "auxiliary_device_add" macro so
	169	* that the caller's KBUILD_MODNAME is automatically inserted for the modname
	170	* parameter. Only if a user requires a custom name would this version be
	171	* called directly.
7de3697e DE	172	*/
	173	int __auxiliary_device_add(struct auxiliary_device auxdev, const char modname)
	174	{
	175	struct device *dev = &auxdev->dev;
	176	int ret;
	177
	178	if (!modname) {
0d2bf11a	179	dev_err(dev, "auxiliary device modname is NULL\n");
7de3697e DE	180	return -EINVAL;
	181	}
	182
	183	ret = dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id);
	184	if (ret) {
0d2bf11a	185	dev_err(dev, "auxiliary device dev_set_name failed: %d\n", ret);
7de3697e DE	186	return ret;
	187	}
	188
	189	ret = device_add(dev);
	190	if (ret)
	191	dev_err(dev, "adding auxiliary device failed!: %d\n", ret);
	192
	193	return ret;
	194	}
	195	EXPORT_SYMBOL_GPL(__auxiliary_device_add);
	196
	197	/**
	198	* auxiliary_find_device - auxiliary device iterator for locating a particular device.
	199	* @start: Device to begin with
	200	* @data: Data to pass to match function
	201	* @match: Callback function to check device
	202	*
	203	* This function returns a reference to a device that is 'found'
	204	* for later use, as determined by the @match callback.
	205	*
	206	* The callback should return 0 if the device doesn't match and non-zero
	207	* if it does. If the callback returns non-zero, this function will
	208	* return to the caller and not iterate over any more devices.
	209	*/
0d2bf11a GKH	210	struct auxiliary_device auxiliary_find_device(struct device start,
	211	const void *data,
	212	int (match)(struct device dev, const void *data))
7de3697e DE	213	{
	214	struct device *dev;
	215
	216	dev = bus_find_device(&auxiliary_bus_type, start, data, match);
	217	if (!dev)
	218	return NULL;
	219
	220	return to_auxiliary_dev(dev);
	221	}
	222	EXPORT_SYMBOL_GPL(auxiliary_find_device);
	223
	224	/**
	225	* __auxiliary_driver_register - register a driver for auxiliary bus devices
	226	* @auxdrv: auxiliary_driver structure
	227	* @owner: owning module/driver
	228	* @modname: KBUILD_MODNAME for parent driver
	229	*/
0d2bf11a GKH	230	int __auxiliary_driver_register(struct auxiliary_driver *auxdrv,
0d2bf11a GKH	231	struct module owner, const char modname)
7de3697e DE	232	{
	233	if (WARN_ON(!auxdrv->probe) \|\| WARN_ON(!auxdrv->id_table))
	234	return -EINVAL;
	235
	236	if (auxdrv->name)
0d2bf11a GKH	237	auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s.%s", modname,
0d2bf11a GKH	238	auxdrv->name);
7de3697e DE	239	else
	240	auxdrv->driver.name = kasprintf(GFP_KERNEL, "%s", modname);
	241	if (!auxdrv->driver.name)
	242	return -ENOMEM;
	243
	244	auxdrv->driver.owner = owner;
	245	auxdrv->driver.bus = &auxiliary_bus_type;
	246	auxdrv->driver.mod_name = modname;
	247
	248	return driver_register(&auxdrv->driver);
	249	}
	250	EXPORT_SYMBOL_GPL(__auxiliary_driver_register);
	251
	252	/**
	253	* auxiliary_driver_unregister - unregister a driver
	254	* @auxdrv: auxiliary_driver structure
	255	*/
	256	void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv)
	257	{
	258	driver_unregister(&auxdrv->driver);
	259	kfree(auxdrv->driver.name);
	260	}
	261	EXPORT_SYMBOL_GPL(auxiliary_driver_unregister);
	262
	263	static int __init auxiliary_bus_init(void)
	264	{
	265	return bus_register(&auxiliary_bus_type);
	266	}
	267
	268	static void __exit auxiliary_bus_exit(void)
	269	{
	270	bus_unregister(&auxiliary_bus_type);
	271	}
	272
	273	module_init(auxiliary_bus_init);
	274	module_exit(auxiliary_bus_exit);
	275
	276	MODULE_LICENSE("GPL v2");
	277	MODULE_DESCRIPTION("Auxiliary Bus");
	278	MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>");
	279	MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>");