Commit | Line | Data |
---|---|---|
a00828e9 PZ |
1 | /* |
2 | * libusual | |
3 | * | |
4 | * The libusual contains the table of devices common for ub and usb-storage. | |
5 | */ | |
6 | #include <linux/kernel.h> | |
7 | #include <linux/module.h> | |
8 | #include <linux/usb.h> | |
9 | #include <linux/usb_usual.h> | |
10 | #include <linux/vmalloc.h> | |
0e3c8c26 | 11 | #include <linux/kthread.h> |
75c43b6e | 12 | #include <linux/mutex.h> |
a00828e9 PZ |
13 | |
14 | /* | |
15 | */ | |
16 | #define USU_MOD_FL_THREAD 1 /* Thread is running */ | |
17 | #define USU_MOD_FL_PRESENT 2 /* The module is loaded */ | |
18 | ||
19 | struct mod_status { | |
20 | unsigned long fls; | |
21 | }; | |
22 | ||
23 | static struct mod_status stat[3]; | |
24 | static DEFINE_SPINLOCK(usu_lock); | |
25 | ||
26 | /* | |
27 | */ | |
28 | #define USB_US_DEFAULT_BIAS USB_US_TYPE_STOR | |
5ba35bd8 | 29 | static atomic_t usu_bias = ATOMIC_INIT(USB_US_DEFAULT_BIAS); |
a00828e9 PZ |
30 | |
31 | #define BIAS_NAME_SIZE (sizeof("usb-storage")) | |
a00828e9 PZ |
32 | static const char *bias_names[3] = { "none", "usb-storage", "ub" }; |
33 | ||
75c43b6e | 34 | static DEFINE_MUTEX(usu_probe_mutex); |
a00828e9 PZ |
35 | static DECLARE_COMPLETION(usu_end_notify); |
36 | static atomic_t total_threads = ATOMIC_INIT(0); | |
37 | ||
38 | static int usu_probe_thread(void *arg); | |
a00828e9 | 39 | |
a00828e9 PZ |
40 | /* |
41 | * @type: the module type as an integer | |
42 | */ | |
43 | void usb_usual_set_present(int type) | |
44 | { | |
45 | struct mod_status *st; | |
46 | unsigned long flags; | |
47 | ||
48 | if (type <= 0 || type >= 3) | |
49 | return; | |
50 | st = &stat[type]; | |
51 | spin_lock_irqsave(&usu_lock, flags); | |
52 | st->fls |= USU_MOD_FL_PRESENT; | |
53 | spin_unlock_irqrestore(&usu_lock, flags); | |
54 | } | |
55 | EXPORT_SYMBOL_GPL(usb_usual_set_present); | |
56 | ||
57 | void usb_usual_clear_present(int type) | |
58 | { | |
59 | struct mod_status *st; | |
60 | unsigned long flags; | |
61 | ||
62 | if (type <= 0 || type >= 3) | |
63 | return; | |
64 | st = &stat[type]; | |
65 | spin_lock_irqsave(&usu_lock, flags); | |
66 | st->fls &= ~USU_MOD_FL_PRESENT; | |
67 | spin_unlock_irqrestore(&usu_lock, flags); | |
68 | } | |
69 | EXPORT_SYMBOL_GPL(usb_usual_clear_present); | |
70 | ||
71 | /* | |
72 | * Match the calling driver type against the table. | |
73 | * Returns: 0 if the device matches. | |
74 | */ | |
75 | int usb_usual_check_type(const struct usb_device_id *id, int caller_type) | |
76 | { | |
77 | int id_type = USB_US_TYPE(id->driver_info); | |
78 | ||
79 | if (caller_type <= 0 || caller_type >= 3) | |
80 | return -EINVAL; | |
81 | ||
82 | /* Drivers grab fixed assignment devices */ | |
83 | if (id_type == caller_type) | |
84 | return 0; | |
85 | /* Drivers grab devices biased to them */ | |
5ba35bd8 | 86 | if (id_type == USB_US_TYPE_NONE && caller_type == atomic_read(&usu_bias)) |
a00828e9 PZ |
87 | return 0; |
88 | return -ENODEV; | |
89 | } | |
90 | EXPORT_SYMBOL_GPL(usb_usual_check_type); | |
91 | ||
92 | /* | |
93 | */ | |
94 | static int usu_probe(struct usb_interface *intf, | |
95 | const struct usb_device_id *id) | |
96 | { | |
64e35d92 | 97 | int rc; |
6d453b9e | 98 | unsigned long type; |
0e3c8c26 | 99 | struct task_struct* task; |
a00828e9 PZ |
100 | unsigned long flags; |
101 | ||
102 | type = USB_US_TYPE(id->driver_info); | |
103 | if (type == 0) | |
5ba35bd8 | 104 | type = atomic_read(&usu_bias); |
a00828e9 PZ |
105 | |
106 | spin_lock_irqsave(&usu_lock, flags); | |
107 | if ((stat[type].fls & (USU_MOD_FL_THREAD|USU_MOD_FL_PRESENT)) != 0) { | |
108 | spin_unlock_irqrestore(&usu_lock, flags); | |
109 | return -ENXIO; | |
110 | } | |
111 | stat[type].fls |= USU_MOD_FL_THREAD; | |
112 | spin_unlock_irqrestore(&usu_lock, flags); | |
113 | ||
04304210 | 114 | task = kthread_run(usu_probe_thread, (void*)type, "libusual_%ld", type); |
0e3c8c26 | 115 | if (IS_ERR(task)) { |
64e35d92 | 116 | rc = PTR_ERR(task); |
a00828e9 PZ |
117 | printk(KERN_WARNING "libusual: " |
118 | "Unable to start the thread for %s: %d\n", | |
119 | bias_names[type], rc); | |
120 | spin_lock_irqsave(&usu_lock, flags); | |
121 | stat[type].fls &= ~USU_MOD_FL_THREAD; | |
122 | spin_unlock_irqrestore(&usu_lock, flags); | |
123 | return rc; /* Not being -ENXIO causes a message printed */ | |
124 | } | |
125 | atomic_inc(&total_threads); | |
126 | ||
127 | return -ENXIO; | |
128 | } | |
129 | ||
130 | static void usu_disconnect(struct usb_interface *intf) | |
131 | { | |
132 | ; /* We should not be here. */ | |
133 | } | |
134 | ||
135 | static struct usb_driver usu_driver = { | |
a00828e9 PZ |
136 | .name = "libusual", |
137 | .probe = usu_probe, | |
138 | .disconnect = usu_disconnect, | |
e6e244b6 | 139 | .id_table = usb_storage_usb_ids, |
a00828e9 PZ |
140 | }; |
141 | ||
142 | /* | |
143 | * A whole new thread for a purpose of request_module seems quite stupid. | |
144 | * The request_module forks once inside again. However, if we attempt | |
145 | * to load a storage module from our own modprobe thread, that module | |
146 | * references our symbols, which cannot be resolved until our module is | |
147 | * initialized. I wish there was a way to wait for the end of initialization. | |
148 | * The module notifier reports MODULE_STATE_COMING only. | |
149 | * So, we wait until module->init ends as the next best thing. | |
150 | */ | |
151 | static int usu_probe_thread(void *arg) | |
152 | { | |
153 | int type = (unsigned long) arg; | |
154 | struct mod_status *st = &stat[type]; | |
155 | int rc; | |
156 | unsigned long flags; | |
157 | ||
75c43b6e | 158 | mutex_lock(&usu_probe_mutex); |
a00828e9 PZ |
159 | rc = request_module(bias_names[type]); |
160 | spin_lock_irqsave(&usu_lock, flags); | |
161 | if (rc == 0 && (st->fls & USU_MOD_FL_PRESENT) == 0) { | |
162 | /* | |
163 | * This should not happen, but let us keep tabs on it. | |
164 | */ | |
165 | printk(KERN_NOTICE "libusual: " | |
166 | "modprobe for %s succeeded, but module is not present\n", | |
167 | bias_names[type]); | |
168 | } | |
169 | st->fls &= ~USU_MOD_FL_THREAD; | |
170 | spin_unlock_irqrestore(&usu_lock, flags); | |
75c43b6e | 171 | mutex_unlock(&usu_probe_mutex); |
a00828e9 PZ |
172 | |
173 | complete_and_exit(&usu_end_notify, 0); | |
174 | } | |
175 | ||
176 | /* | |
177 | */ | |
178 | static int __init usb_usual_init(void) | |
179 | { | |
180 | int rc; | |
181 | ||
75c43b6e | 182 | mutex_lock(&usu_probe_mutex); |
a00828e9 | 183 | rc = usb_register(&usu_driver); |
75c43b6e | 184 | mutex_unlock(&usu_probe_mutex); |
a00828e9 PZ |
185 | return rc; |
186 | } | |
187 | ||
188 | static void __exit usb_usual_exit(void) | |
189 | { | |
190 | /* | |
191 | * We do not check for any drivers present, because | |
192 | * they keep us pinned with symbol references. | |
193 | */ | |
194 | ||
195 | usb_deregister(&usu_driver); | |
196 | ||
197 | while (atomic_read(&total_threads) > 0) { | |
198 | wait_for_completion(&usu_end_notify); | |
199 | atomic_dec(&total_threads); | |
200 | } | |
201 | } | |
202 | ||
203 | /* | |
204 | * Validate and accept the bias parameter. | |
a00828e9 | 205 | */ |
5ba35bd8 | 206 | static int usu_set_bias(const char *bias_s, struct kernel_param *kp) |
a00828e9 PZ |
207 | { |
208 | int i; | |
5ba35bd8 | 209 | int len; |
a00828e9 PZ |
210 | int bias_n = 0; |
211 | ||
5ba35bd8 PZ |
212 | len = strlen(bias_s); |
213 | if (len == 0) | |
214 | return -EDOM; | |
215 | if (bias_s[len-1] == '\n') | |
216 | --len; | |
217 | ||
218 | for (i = 1; i < 3; i++) { | |
219 | if (strncmp(bias_s, bias_names[i], len) == 0) { | |
220 | bias_n = i; | |
221 | break; | |
a00828e9 PZ |
222 | } |
223 | } | |
5ba35bd8 PZ |
224 | if (bias_n == 0) |
225 | return -EINVAL; | |
226 | ||
227 | atomic_set(&usu_bias, bias_n); | |
228 | return 0; | |
229 | } | |
230 | ||
231 | static int usu_get_bias(char *buffer, struct kernel_param *kp) | |
232 | { | |
233 | return strlen(strcpy(buffer, bias_names[atomic_read(&usu_bias)])); | |
a00828e9 PZ |
234 | } |
235 | ||
236 | module_init(usb_usual_init); | |
237 | module_exit(usb_usual_exit); | |
238 | ||
5ba35bd8 PZ |
239 | module_param_call(bias, usu_set_bias, usu_get_bias, NULL, S_IRUGO|S_IWUSR); |
240 | __MODULE_PARM_TYPE(bias, "string"); | |
a00828e9 PZ |
241 | MODULE_PARM_DESC(bias, "Bias to usb-storage or ub"); |
242 | ||
243 | MODULE_LICENSE("GPL"); |