1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Bus for UWB Multi-interface Controller capabilities.
4  *
5  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
6  */
7 #include <linux/kernel.h>
8 #include <linux/sysfs.h>
9 #include <linux/workqueue.h>
10 #include <linux/module.h>
11 #include <linux/pci.h>
12 #include "include/umc.h"
13 
umc_bus_pre_reset_helper(struct device * dev,void * data)14 static int umc_bus_pre_reset_helper(struct device *dev, void *data)
15 {
16 	int ret = 0;
17 
18 	if (dev->driver) {
19 		struct umc_dev *umc = to_umc_dev(dev);
20 		struct umc_driver *umc_drv = to_umc_driver(dev->driver);
21 
22 		if (umc_drv->pre_reset)
23 			ret = umc_drv->pre_reset(umc);
24 		else
25 			device_release_driver(dev);
26 	}
27 	return ret;
28 }
29 
umc_bus_post_reset_helper(struct device * dev,void * data)30 static int umc_bus_post_reset_helper(struct device *dev, void *data)
31 {
32 	int ret = 0;
33 
34 	if (dev->driver) {
35 		struct umc_dev *umc = to_umc_dev(dev);
36 		struct umc_driver *umc_drv = to_umc_driver(dev->driver);
37 
38 		if (umc_drv->post_reset)
39 			ret = umc_drv->post_reset(umc);
40 	} else
41 		ret = device_attach(dev);
42 
43 	return ret;
44 }
45 
46 /**
47  * umc_controller_reset - reset the whole UMC controller
48  * @umc: the UMC device for the radio controller.
49  *
50  * Drivers or all capabilities of the controller will have their
51  * pre_reset methods called or be unbound from their device.  Then all
52  * post_reset methods will be called or the drivers will be rebound.
53  *
54  * Radio controllers must provide pre_reset and post_reset methods and
55  * reset the hardware in their start method.
56  *
57  * If this is called while a probe() or remove() is in progress it
58  * will return -EAGAIN and not perform the reset.
59  */
umc_controller_reset(struct umc_dev * umc)60 int umc_controller_reset(struct umc_dev *umc)
61 {
62 	struct device *parent = umc->dev.parent;
63 	int ret = 0;
64 
65 	if (!device_trylock(parent))
66 		return -EAGAIN;
67 	ret = device_for_each_child(parent, parent, umc_bus_pre_reset_helper);
68 	if (ret >= 0)
69 		ret = device_for_each_child(parent, parent, umc_bus_post_reset_helper);
70 	device_unlock(parent);
71 
72 	return ret;
73 }
74 EXPORT_SYMBOL_GPL(umc_controller_reset);
75 
76 /**
77  * umc_match_pci_id - match a UMC driver to a UMC device's parent PCI device.
78  * @umc_drv: umc driver with match_data pointing to a zero-terminated
79  * table of pci_device_id's.
80  * @umc: umc device whose parent is to be matched.
81  */
umc_match_pci_id(struct umc_driver * umc_drv,struct umc_dev * umc)82 int umc_match_pci_id(struct umc_driver *umc_drv, struct umc_dev *umc)
83 {
84 	const struct pci_device_id *id_table = umc_drv->match_data;
85 	struct pci_dev *pci;
86 
87 	if (!dev_is_pci(umc->dev.parent))
88 		return 0;
89 
90 	pci = to_pci_dev(umc->dev.parent);
91 	return pci_match_id(id_table, pci) != NULL;
92 }
93 EXPORT_SYMBOL_GPL(umc_match_pci_id);
94 
umc_bus_rescan_helper(struct device * dev,void * data)95 static int umc_bus_rescan_helper(struct device *dev, void *data)
96 {
97 	int ret = 0;
98 
99 	if (!dev->driver)
100 		ret = device_attach(dev);
101 
102 	return ret;
103 }
104 
umc_bus_rescan(struct device * parent)105 static void umc_bus_rescan(struct device *parent)
106 {
107 	int err;
108 
109 	/*
110 	 * We can't use bus_rescan_devices() here as it deadlocks when
111 	 * it tries to retake the dev->parent semaphore.
112 	 */
113 	err = device_for_each_child(parent, NULL, umc_bus_rescan_helper);
114 	if (err < 0)
115 		printk(KERN_WARNING "%s: rescan of bus failed: %d\n",
116 		       KBUILD_MODNAME, err);
117 }
118 
umc_bus_match(struct device * dev,struct device_driver * drv)119 static int umc_bus_match(struct device *dev, struct device_driver *drv)
120 {
121 	struct umc_dev *umc = to_umc_dev(dev);
122 	struct umc_driver *umc_driver = to_umc_driver(drv);
123 
124 	if (umc->cap_id == umc_driver->cap_id) {
125 		if (umc_driver->match)
126 			return umc_driver->match(umc_driver, umc);
127 		else
128 			return 1;
129 	}
130 	return 0;
131 }
132 
umc_device_probe(struct device * dev)133 static int umc_device_probe(struct device *dev)
134 {
135 	struct umc_dev *umc;
136 	struct umc_driver *umc_driver;
137 	int err;
138 
139 	umc_driver = to_umc_driver(dev->driver);
140 	umc = to_umc_dev(dev);
141 
142 	get_device(dev);
143 	err = umc_driver->probe(umc);
144 	if (err)
145 		put_device(dev);
146 	else
147 		umc_bus_rescan(dev->parent);
148 
149 	return err;
150 }
151 
umc_device_remove(struct device * dev)152 static int umc_device_remove(struct device *dev)
153 {
154 	struct umc_dev *umc;
155 	struct umc_driver *umc_driver;
156 
157 	umc_driver = to_umc_driver(dev->driver);
158 	umc = to_umc_dev(dev);
159 
160 	umc_driver->remove(umc);
161 	put_device(dev);
162 	return 0;
163 }
164 
capability_id_show(struct device * dev,struct device_attribute * attr,char * buf)165 static ssize_t capability_id_show(struct device *dev, struct device_attribute *attr, char *buf)
166 {
167 	struct umc_dev *umc = to_umc_dev(dev);
168 
169 	return sprintf(buf, "0x%02x\n", umc->cap_id);
170 }
171 static DEVICE_ATTR_RO(capability_id);
172 
version_show(struct device * dev,struct device_attribute * attr,char * buf)173 static ssize_t version_show(struct device *dev, struct device_attribute *attr, char *buf)
174 {
175 	struct umc_dev *umc = to_umc_dev(dev);
176 
177 	return sprintf(buf, "0x%04x\n", umc->version);
178 }
179 static DEVICE_ATTR_RO(version);
180 
181 static struct attribute *umc_dev_attrs[] = {
182 	&dev_attr_capability_id.attr,
183 	&dev_attr_version.attr,
184 	NULL,
185 };
186 ATTRIBUTE_GROUPS(umc_dev);
187 
188 struct bus_type umc_bus_type = {
189 	.name		= "umc",
190 	.match		= umc_bus_match,
191 	.probe		= umc_device_probe,
192 	.remove		= umc_device_remove,
193 	.dev_groups	= umc_dev_groups,
194 };
195 EXPORT_SYMBOL_GPL(umc_bus_type);
196 
umc_bus_init(void)197 static int __init umc_bus_init(void)
198 {
199 	return bus_register(&umc_bus_type);
200 }
201 module_init(umc_bus_init);
202 
umc_bus_exit(void)203 static void __exit umc_bus_exit(void)
204 {
205 	bus_unregister(&umc_bus_type);
206 }
207 module_exit(umc_bus_exit);
208 
209 MODULE_DESCRIPTION("UWB Multi-interface Controller capability bus");
210 MODULE_AUTHOR("Cambridge Silicon Radio Ltd.");
211 MODULE_LICENSE("GPL");
212