drivers/char/misc.c

   1 /*
   2  * linux/drivers/char/misc.c
   3  *
   4  * Generic misc open routine by Johan Myreen
   5  *
   6  * Based on code from Linus
   7  *
   8  * Teemu Rantanen's Microsoft Busmouse support and Derrick Cole's
   9  *   changes incorporated into 0.97pl4
  10  *   by Peter Cervasio (pete%q106fm.uucp@wupost.wustl.edu) (08SEP92)
  11  *   See busmouse.c for particulars.
  12  *
  13  * Made things a lot mode modular - easy to compile in just one or two
  14  * of the misc drivers, as they are now completely independent. Linus.
  15  *
  16  * Support for loadable modules. 8-Sep-95 Philip Blundell <pjb27@cam.ac.uk>
  17  *
  18  * Fixed a failing symbol register to free the device registration
  19  *              Alan Cox <alan@lxorguk.ukuu.org.uk> 21-Jan-96
  20  *
  21  * Dynamic minors and /proc/mice by Alessandro Rubini. 26-Mar-96
  22  *
  23  * Renamed to misc and miscdevice to be more accurate. Alan Cox 26-Mar-96
  24  *
  25  * Handling of mouse minor numbers for kerneld:
  26  *  Idea by Jacques Gelinas <jack@solucorp.qc.ca>,
  27  *  adapted by Bjorn Ekwall <bj0rn@blox.se>
  28  *  corrected by Alan Cox <alan@lxorguk.ukuu.org.uk>
  29  *
  30  * Changes for kmod (from kerneld):
  31         Cyrus Durgin <cider@speakeasy.org>
  32  */
  33
  34 #include <linux/config.h>
  35 #include <linux/module.h>
  36
  37 #include <linux/fs.h>
  38 #include <linux/errno.h>
  39 #include <linux/miscdevice.h>
  40 #include <linux/kernel.h>
  41 #include <linux/major.h>
  42 #include <linux/malloc.h>
  43 #include <linux/proc_fs.h>
  44 #include <linux/stat.h>
  45 #include <linux/init.h>
  46 #ifdef CONFIG_APM
  47 #include <linux/apm_bios.h>
  48 #endif
  49
  50 #include <linux/tty.h>
  51 #include <linux/selection.h>
  52 #ifdef CONFIG_KMOD
  53 #include <linux/kmod.h>
  54 #endif
  55
  56 /*
  57  * Head entry for the doubly linked miscdevice list
  58  */
  59 static struct miscdevice misc_list = { 0, "head", NULL, &misc_list, &misc_list };
  60
  61 /*
  62  * Assigned numbers, used for dynamic minors
  63  */
  64 #define DYNAMIC_MINORS 64 /* like dynamic majors */
  65 static unsigned char misc_minors[DYNAMIC_MINORS / 8];
  66
  67 #ifndef MODULE
  68 extern int adbdev_init(void);
  69 extern int bus_mouse_init(void);
  70 extern int psaux_init(void);
  71 extern int ms_bus_mouse_init(void);
  72 extern int atixl_busmouse_init(void);
  73 extern int amiga_mouse_init(void);
  74 extern int atari_mouse_init(void);
  75 extern int mac_mouse_init(void);
  76 extern int sun_mouse_init(void);
  77 extern int adb_mouse_init(void);
  78 extern void watchdog_init(void);
  79 extern void wdt_init(void);
  80 extern void acq_init(void);
  81 extern void pcwatchdog_init(void);
  82 extern int rtc_init(void);
  83 extern int dsp56k_init(void);
  84 extern int nvram_init(void);
  85 extern int radio_init(void);
  86 extern void hfmodem_init(void);
  87 extern int pc110pad_init(void);
  88 extern int pmu_device_init(void);
  89
  90 #ifdef CONFIG_PROC_FS
  91 static int misc_read_proc(char *buf, char **start, off_t offset,
  92                           int len, int *eof, void *private)
  93 {
  94         struct miscdevice *p;
  95
  96         len=0;
  97         for (p = misc_list.next; p != &misc_list && len < 4000; p = p->next)
  98                 len += sprintf(buf+len, "%3i %s\n",p->minor, p->name ?: "");
  99         *start = buf + offset;
 100         return len > offset ? len - offset : 0;
 101 }
 102
 103 #endif /* PROC_FS */
 104 #endif /* !MODULE */
 105
 106 static int misc_open(struct inode * inode, struct file * file)
 107 {
 108         int minor = MINOR(inode->i_rdev);
 109         struct miscdevice *c = misc_list.next;
 110         file->f_op = NULL;
 111
 112         while ((c != &misc_list) && (c->minor != minor))
 113                 c = c->next;
 114         if (c == &misc_list) {
 115 #ifdef CONFIG_KMOD
 116                 char modname[20];
 117                 sprintf(modname, "char-major-%d-%d", MISC_MAJOR, minor);
 118                 request_module(modname);
 119                 c = misc_list.next;
 120                 while ((c != &misc_list) && (c->minor != minor))
 121                         c = c->next;
 122                 if (c == &misc_list)
 123 #endif
 124                         return -ENODEV;
 125         }
 126
 127         if ((file->f_op = c->fops) && file->f_op->open)
 128                 return file->f_op->open(inode,file);
 129         else
 130                 return -ENODEV;
 131 }
 132
 133 static struct file_operations misc_fops = {
 134         NULL,           /* seek */
 135         NULL,           /* read */
 136         NULL,           /* write */
 137         NULL,           /* readdir */
 138         NULL,           /* poll */
 139         NULL,           /* ioctl */
 140         NULL,           /* mmap */
 141         misc_open,
 142         NULL,           /* flush */
 143         NULL            /* release */
 144 };
 145
 146 int misc_register(struct miscdevice * misc)
 147 {
 148         if (misc->next || misc->prev)
 149                 return -EBUSY;
 150         if (misc->minor == MISC_DYNAMIC_MINOR) {
 151                 int i = DYNAMIC_MINORS;
 152                 while (--i >= 0)
 153                         if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
 154                                 break;
 155                 if (i<0) return -EBUSY;
 156                 misc->minor = i;
 157         }
 158         if (misc->minor < DYNAMIC_MINORS)
 159                 misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
 160         MOD_INC_USE_COUNT;
 161         misc->next = &misc_list;
 162         misc->prev = misc_list.prev;
 163         misc->prev->next = misc;
 164         misc->next->prev = misc;
 165         return 0;
 166 }
 167
 168 int misc_deregister(struct miscdevice * misc)
 169 {
 170         int i = misc->minor;
 171         if (!misc->next || !misc->prev)
 172                 return -EINVAL;
 173         MOD_DEC_USE_COUNT;
 174         misc->prev->next = misc->next;
 175         misc->next->prev = misc->prev;
 176         misc->next = NULL;
 177         misc->prev = NULL;
 178         if (i < DYNAMIC_MINORS && i>0) {
 179                 misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
 180         }
 181         return 0;
 182 }
 183
 184 #ifdef MODULE
 185
 186 #define misc_init init_module
 187
 188 void cleanup_module(void)
 189 {
 190         unregister_chrdev(MISC_MAJOR, "misc");
 191 }
 192
 193 #endif
 194
 195 EXPORT_SYMBOL(misc_register);
 196 EXPORT_SYMBOL(misc_deregister);
 197
 198 #if defined(CONFIG_PROC_FS) && !defined(MODULE)
 199 static struct proc_dir_entry *proc_misc;
 200 #endif
 201
 202 __initfunc(int misc_init(void))
 203 {
 204 #ifndef MODULE
 205 #ifdef CONFIG_PROC_FS
 206         proc_misc = create_proc_entry("misc", 0, 0);
 207         if (proc_misc)
 208                 proc_misc->read_proc = misc_read_proc;
 209 #endif /* PROC_FS */
 210 #ifdef CONFIG_MAC
 211         adbdev_init();
 212 #endif
 213 #ifdef CONFIG_BUSMOUSE
 214         bus_mouse_init();
 215 #endif
 216 #if defined CONFIG_PSMOUSE
 217         psaux_init();
 218 #endif
 219 #ifdef CONFIG_MS_BUSMOUSE
 220         ms_bus_mouse_init();
 221 #endif
 222 #ifdef CONFIG_ATIXL_BUSMOUSE
 223         atixl_busmouse_init();
 224 #endif
 225 #ifdef CONFIG_AMIGAMOUSE
 226         amiga_mouse_init();
 227 #endif
 228 #ifdef CONFIG_ATARIMOUSE
 229         atari_mouse_init();
 230 #endif
 231 #ifdef CONFIG_MACMOUSE
 232         mac_mouse_init();
 233 #endif
 234 #ifdef CONFIG_SUN_MOUSE
 235         sun_mouse_init();
 236 #endif
 237 #ifdef CONFIG_MACMOUSE
 238         adb_mouse_init();
 239 #endif
 240 #ifdef CONFIG_PC110_PAD
 241         pc110pad_init();
 242 #endif
 243 /*
 244  *      Only one watchdog can succeed. We probe the pcwatchdog first,
 245  *      then the wdt cards and finally the software watchdog which always
 246  *      works. This means if your hardware watchdog dies or is 'borrowed'
 247  *      for some reason the software watchdog still gives you some cover.
 248  */
 249 #ifdef CONFIG_PCWATCHDOG
 250         pcwatchdog_init();
 251 #endif
 252 #ifdef CONFIG_WDT
 253         wdt_init();
 254 #endif
 255 #ifdef CONFIG_ACQUIRE_WDT
 256         acq_init();
 257 #endif
 258 #ifdef CONFIG_SOFT_WATCHDOG
 259         watchdog_init();
 260 #endif
 261 #ifdef CONFIG_APM
 262         apm_bios_init();
 263 #endif
 264 #ifdef CONFIG_H8
 265         h8_init();
 266 #endif
 267 #if defined(CONFIG_RTC) || defined(CONFIG_SUN_MOSTEK_RTC)
 268         rtc_init();
 269 #endif
 270 #ifdef CONFIG_ATARI_DSP56K
 271         dsp56k_init();
 272 #endif
 273 #ifdef CONFIG_HFMODEM
 274         hfmodem_init();
 275 #endif
 276 #ifdef CONFIG_NVRAM
 277         nvram_init();
 278 #endif
 279 #ifdef CONFIG_MISC_RADIO
 280         radio_init();
 281 #endif
 282 #ifdef CONFIG_HFMODEM
 283         hfmodem_init();
 284 #endif
 285 #ifdef CONFIG_PMAC_PBOOK
 286         pmu_device_init();
 287 #endif
 288 #endif /* !MODULE */
 289         if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
 290                 printk("unable to get major %d for misc devices\n",
 291                        MISC_MAJOR);
 292                 return -EIO;
 293         }
 294
 295         return 0;
 296 }