kernel/2.6.29.6-aldebaran-rt/drivers/usb/storage/libusual.c

   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>
  11 #include <linux/kthread.h>
  12 #include <linux/mutex.h>
  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
  29 static atomic_t usu_bias = ATOMIC_INIT(USB_US_DEFAULT_BIAS);
  30
  31 #define BIAS_NAME_SIZE  (sizeof("usb-storage"))
  32 static const char *bias_names[3] = { "none", "usb-storage", "ub" };
  33
  34 static DEFINE_MUTEX(usu_probe_mutex);
  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);
  39
  40 /*
  41  * The table.
  42  */
  43 #define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
  44                     vendorName, productName,useProtocol, useTransport, \
  45                     initFunction, flags) \
  46 { USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin,bcdDeviceMax), \
  47   .driver_info = (flags)|(USB_US_TYPE_STOR<<24) }
  48
  49 #define COMPLIANT_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
  50                     vendorName, productName, useProtocol, useTransport, \
  51                     initFunction, flags) \
  52 { USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax), \
  53   .driver_info = (flags) }
  54
  55 #define USUAL_DEV(useProto, useTrans, useType) \
  56 { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, useProto, useTrans), \
  57   .driver_info = ((useType)<<24) }
  58
  59 struct usb_device_id storage_usb_ids [] = {
  60 #       include "unusual_devs.h"
  61         { } /* Terminating entry */
  62 };
  63
  64 #undef USUAL_DEV
  65 #undef UNUSUAL_DEV
  66 #undef COMPLIANT_DEV
  67
  68 MODULE_DEVICE_TABLE(usb, storage_usb_ids);
  69 EXPORT_SYMBOL_GPL(storage_usb_ids);
  70
  71 /*
  72  * @type: the module type as an integer
  73  */
  74 void usb_usual_set_present(int type)
  75 {
  76         struct mod_status *st;
  77         unsigned long flags;
  78
  79         if (type <= 0 || type >= 3)
  80                 return;
  81         st = &stat[type];
  82         spin_lock_irqsave(&usu_lock, flags);
  83         st->fls |= USU_MOD_FL_PRESENT;
  84         spin_unlock_irqrestore(&usu_lock, flags);
  85 }
  86 EXPORT_SYMBOL_GPL(usb_usual_set_present);
  87
  88 void usb_usual_clear_present(int type)
  89 {
  90         struct mod_status *st;
  91         unsigned long flags;
  92
  93         if (type <= 0 || type >= 3)
  94                 return;
  95         st = &stat[type];
  96         spin_lock_irqsave(&usu_lock, flags);
  97         st->fls &= ~USU_MOD_FL_PRESENT;
  98         spin_unlock_irqrestore(&usu_lock, flags);
  99 }
 100 EXPORT_SYMBOL_GPL(usb_usual_clear_present);
 101
 102 /*
 103  * Match the calling driver type against the table.
 104  * Returns: 0 if the device matches.
 105  */
 106 int usb_usual_check_type(const struct usb_device_id *id, int caller_type)
 107 {
 108         int id_type = USB_US_TYPE(id->driver_info);
 109
 110         if (caller_type <= 0 || caller_type >= 3)
 111                 return -EINVAL;
 112
 113         /* Drivers grab fixed assignment devices */
 114         if (id_type == caller_type)
 115                 return 0;
 116         /* Drivers grab devices biased to them */
 117         if (id_type == USB_US_TYPE_NONE && caller_type == atomic_read(&usu_bias))
 118                 return 0;
 119         return -ENODEV;
 120 }
 121 EXPORT_SYMBOL_GPL(usb_usual_check_type);
 122
 123 /*
 124  */
 125 static int usu_probe(struct usb_interface *intf,
 126                          const struct usb_device_id *id)
 127 {
 128         int rc;
 129         unsigned long type;
 130         struct task_struct* task;
 131         unsigned long flags;
 132
 133         type = USB_US_TYPE(id->driver_info);
 134         if (type == 0)
 135                 type = atomic_read(&usu_bias);
 136
 137         spin_lock_irqsave(&usu_lock, flags);
 138         if ((stat[type].fls & (USU_MOD_FL_THREAD|USU_MOD_FL_PRESENT)) != 0) {
 139                 spin_unlock_irqrestore(&usu_lock, flags);
 140                 return -ENXIO;
 141         }
 142         stat[type].fls |= USU_MOD_FL_THREAD;
 143         spin_unlock_irqrestore(&usu_lock, flags);
 144
 145         task = kthread_run(usu_probe_thread, (void*)type, "libusual_%ld", type);
 146         if (IS_ERR(task)) {
 147                 rc = PTR_ERR(task);
 148                 printk(KERN_WARNING "libusual: "
 149                     "Unable to start the thread for %s: %d\n",
 150                     bias_names[type], rc);
 151                 spin_lock_irqsave(&usu_lock, flags);
 152                 stat[type].fls &= ~USU_MOD_FL_THREAD;
 153                 spin_unlock_irqrestore(&usu_lock, flags);
 154                 return rc;      /* Not being -ENXIO causes a message printed */
 155         }
 156         atomic_inc(&total_threads);
 157
 158         return -ENXIO;
 159 }
 160
 161 static void usu_disconnect(struct usb_interface *intf)
 162 {
 163         ;       /* We should not be here. */
 164 }
 165
 166 static struct usb_driver usu_driver = {
 167         .name =         "libusual",
 168         .probe =        usu_probe,
 169         .disconnect =   usu_disconnect,
 170         .id_table =     storage_usb_ids,
 171 };
 172
 173 /*
 174  * A whole new thread for a purpose of request_module seems quite stupid.
 175  * The request_module forks once inside again. However, if we attempt
 176  * to load a storage module from our own modprobe thread, that module
 177  * references our symbols, which cannot be resolved until our module is
 178  * initialized. I wish there was a way to wait for the end of initialization.
 179  * The module notifier reports MODULE_STATE_COMING only.
 180  * So, we wait until module->init ends as the next best thing.
 181  */
 182 static int usu_probe_thread(void *arg)
 183 {
 184         int type = (unsigned long) arg;
 185         struct mod_status *st = &stat[type];
 186         int rc;
 187         unsigned long flags;
 188
 189         mutex_lock(&usu_probe_mutex);
 190         rc = request_module(bias_names[type]);
 191         spin_lock_irqsave(&usu_lock, flags);
 192         if (rc == 0 && (st->fls & USU_MOD_FL_PRESENT) == 0) {
 193                 /*
 194                  * This should not happen, but let us keep tabs on it.
 195                  */
 196                 printk(KERN_NOTICE "libusual: "
 197                     "modprobe for %s succeeded, but module is not present\n",
 198                     bias_names[type]);
 199         }
 200         st->fls &= ~USU_MOD_FL_THREAD;
 201         spin_unlock_irqrestore(&usu_lock, flags);
 202         mutex_unlock(&usu_probe_mutex);
 203
 204         complete_and_exit(&usu_end_notify, 0);
 205 }
 206
 207 /*
 208  */
 209 static int __init usb_usual_init(void)
 210 {
 211         int rc;
 212
 213         mutex_lock(&usu_probe_mutex);
 214         rc = usb_register(&usu_driver);
 215         mutex_unlock(&usu_probe_mutex);
 216         return rc;
 217 }
 218
 219 static void __exit usb_usual_exit(void)
 220 {
 221         /*
 222          * We do not check for any drivers present, because
 223          * they keep us pinned with symbol references.
 224          */
 225
 226         usb_deregister(&usu_driver);
 227
 228         while (atomic_read(&total_threads) > 0) {
 229                 wait_for_completion(&usu_end_notify);
 230                 atomic_dec(&total_threads);
 231         }
 232 }
 233
 234 /*
 235  * Validate and accept the bias parameter.
 236  */
 237 static int usu_set_bias(const char *bias_s, struct kernel_param *kp)
 238 {
 239         int i;
 240         int len;
 241         int bias_n = 0;
 242
 243         len = strlen(bias_s);
 244         if (len == 0)
 245                 return -EDOM;
 246         if (bias_s[len-1] == '\n')
 247                 --len;
 248
 249         for (i = 1; i < 3; i++) {
 250                 if (strncmp(bias_s, bias_names[i], len) == 0) {
 251                         bias_n = i;
 252                         break;
 253                 }
 254         }
 255         if (bias_n == 0)
 256                 return -EINVAL;
 257
 258         atomic_set(&usu_bias, bias_n);
 259         return 0;
 260 }
 261
 262 static int usu_get_bias(char *buffer, struct kernel_param *kp)
 263 {
 264         return strlen(strcpy(buffer, bias_names[atomic_read(&usu_bias)]));
 265 }
 266
 267 module_init(usb_usual_init);
 268 module_exit(usb_usual_exit);
 269
 270 module_param_call(bias, usu_set_bias, usu_get_bias, NULL, S_IRUGO|S_IWUSR);
 271 __MODULE_PARM_TYPE(bias, "string");
 272 MODULE_PARM_DESC(bias, "Bias to usb-storage or ub");
 273
 274 MODULE_LICENSE("GPL");