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
  31 #include <linux/config.h>
  32 #include <linux/module.h>
  33
  34 #include <linux/fs.h>
  35 #include <linux/errno.h>
  36 #include <linux/miscdevice.h>
  37 #include <linux/kernel.h>
  38 #include <linux/major.h>
  39 #include <linux/malloc.h>
  40 #include <linux/proc_fs.h>
  41 #include <linux/stat.h>
  42 #include <linux/init.h>
  43 #ifdef CONFIG_APM
  44 #include <linux/apm_bios.h>
  45 #endif
  46
  47 #include <linux/tty.h>
  48 #include <linux/selection.h>
  49 #ifdef CONFIG_KERNELD
  50 #include <linux/kerneld.h>
  51 #endif
  52
  53 /*
  54  * Head entry for the doubly linked miscdevice list
  55  */
  56 static struct miscdevice misc_list = { 0, "head", NULL, &misc_list, &misc_list };
  57
  58 /*
  59  * Assigned numbers, used for dynamic minors
  60  */
  61 #define DYNAMIC_MINORS 64 /* like dynamic majors */
  62 static unsigned char misc_minors[DYNAMIC_MINORS / 8];
  63
  64 #ifndef MODULE
  65 extern int bus_mouse_init(void);
  66 extern int psaux_init(void);
  67 extern int ms_bus_mouse_init(void);
  68 extern int atixl_busmouse_init(void);
  69 extern int amiga_mouse_init(void);
  70 extern int atari_mouse_init(void);
  71 extern int sun_mouse_init(void);
  72 extern void watchdog_init(void);
  73 extern void wdt_init(void);
  74 extern void acq_init(void);
  75 extern void pcwatchdog_init(void);
  76 extern int rtc_init(void);
  77 extern int dsp56k_init(void);
  78 extern int nvram_init(void);
  79 extern int radio_init(void);
  80 extern void hfmodem_init(void);
  81 #ifdef CONFIG_PC110_PAD
  82 extern int pc110pad_init(void);
  83 #endif
  84
  85 #ifdef CONFIG_PROC_FS
  86 static int misc_read_proc(char *buf, char **start, off_t offset,
  87                           int len, int *eof, void *private)
  88 {
  89         struct miscdevice *p;
  90
  91         len=0;
  92         for (p = misc_list.next; p != &misc_list && len < 4000; p = p->next)
  93                 len += sprintf(buf+len, "%3i %s\n",p->minor, p->name ?: "");
  94         *start = buf + offset;
  95         return len > offset ? len - offset : 0;
  96 }
  97
  98 #endif /* PROC_FS */
  99 #endif /* !MODULE */
 100
 101 static int misc_open(struct inode * inode, struct file * file)
 102 {
 103         int minor = MINOR(inode->i_rdev);
 104         struct miscdevice *c = misc_list.next;
 105         file->f_op = NULL;
 106
 107         while ((c != &misc_list) && (c->minor != minor))
 108                 c = c->next;
 109         if (c == &misc_list) {
 110 #ifdef CONFIG_KERNELD
 111                 char modname[20];
 112                 sprintf(modname, "char-major-%d-%d", MISC_MAJOR, minor);
 113                 request_module(modname);
 114                 c = misc_list.next;
 115                 while ((c != &misc_list) && (c->minor != minor))
 116                         c = c->next;
 117                 if (c == &misc_list)
 118 #endif
 119                         return -ENODEV;
 120         }
 121
 122         if ((file->f_op = c->fops) && file->f_op->open)
 123                 return file->f_op->open(inode,file);
 124         else
 125                 return -ENODEV;
 126 }
 127
 128 static struct file_operations misc_fops = {
 129         NULL,           /* seek */
 130         NULL,           /* read */
 131         NULL,           /* write */
 132         NULL,           /* readdir */
 133         NULL,           /* poll */
 134         NULL,           /* ioctl */
 135         NULL,           /* mmap */
 136         misc_open,
 137         NULL            /* release */
 138 };
 139
 140 int misc_register(struct miscdevice * misc)
 141 {
 142         if (misc->next || misc->prev)
 143                 return -EBUSY;
 144         if (misc->minor == MISC_DYNAMIC_MINOR) {
 145                 int i = DYNAMIC_MINORS;
 146                 while (--i >= 0)
 147                         if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
 148                                 break;
 149                 if (i<0) return -EBUSY;
 150                 misc->minor = i;
 151         }
 152         if (misc->minor < DYNAMIC_MINORS)
 153                 misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
 154         MOD_INC_USE_COUNT;
 155         misc->next = &misc_list;
 156         misc->prev = misc_list.prev;
 157         misc->prev->next = misc;
 158         misc->next->prev = misc;
 159         return 0;
 160 }
 161
 162 int misc_deregister(struct miscdevice * misc)
 163 {
 164         int i = misc->minor;
 165         if (!misc->next || !misc->prev)
 166                 return -EINVAL;
 167         MOD_DEC_USE_COUNT;
 168         misc->prev->next = misc->next;
 169         misc->next->prev = misc->prev;
 170         misc->next = NULL;
 171         misc->prev = NULL;
 172         if (i < DYNAMIC_MINORS && i>0) {
 173                 misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
 174         }
 175         return 0;
 176 }
 177
 178 #ifdef MODULE
 179
 180 #define misc_init init_module
 181
 182 void cleanup_module(void)
 183 {
 184         unregister_chrdev(MISC_MAJOR, "misc");
 185 }
 186
 187 #endif
 188
 189 EXPORT_SYMBOL(misc_register);
 190 EXPORT_SYMBOL(misc_deregister);
 191
 192 #if defined(CONFIG_PROC_FS) && !defined(MODULE)
 193 static struct proc_dir_entry *proc_misc;
 194 #endif
 195
 196 __initfunc(int misc_init(void))
 197 {
 198 #ifndef MODULE
 199 #ifdef CONFIG_PROC_FS
 200         proc_misc = create_proc_entry("misc", 0, 0);
 201         if (proc_misc)
 202                 proc_misc->read_proc = misc_read_proc;
 203 #endif /* PROC_FS */
 204 #ifdef CONFIG_BUSMOUSE
 205         bus_mouse_init();
 206 #endif
 207 #if defined CONFIG_PSMOUSE
 208         psaux_init();
 209 #endif
 210 #ifdef CONFIG_MS_BUSMOUSE
 211         ms_bus_mouse_init();
 212 #endif
 213 #ifdef CONFIG_ATIXL_BUSMOUSE
 214         atixl_busmouse_init();
 215 #endif
 216 #ifdef CONFIG_AMIGAMOUSE
 217         amiga_mouse_init();
 218 #endif
 219 #ifdef CONFIG_ATARIMOUSE
 220         atari_mouse_init();
 221 #endif
 222 #ifdef CONFIG_SUN_MOUSE
 223         sun_mouse_init();
 224 #endif
 225 #ifdef CONFIG_PC110_PAD
 226         pc110pad_init();
 227 #endif
 228 /*
 229  *      Only one watchdog can succeed. We probe the pcwatchdog first,
 230  *      then the wdt cards and finally the software watchdog which always
 231  *      works. This means if your hardware watchdog dies or is 'borrowed'
 232  *      for some reason the software watchdog still gives you some cover.
 233  */
 234 #ifdef CONFIG_PCWATCHDOG
 235         pcwatchdog_init();
 236 #endif
 237 #ifdef CONFIG_WDT
 238         wdt_init();
 239 #endif
 240 #ifdef CONFIG_ACQUIRE_WDT
 241         acq_init();
 242 #endif
 243 #ifdef CONFIG_SOFT_WATCHDOG
 244         watchdog_init();
 245 #endif
 246 #ifdef CONFIG_APM
 247         apm_bios_init();
 248 #endif
 249 #ifdef CONFIG_H8
 250         h8_init();
 251 #endif
 252 #ifdef CONFIG_RTC
 253         rtc_init();
 254 #endif
 255 #ifdef CONFIG_ATARI_DSP56K
 256         dsp56k_init();
 257 #endif
 258 #ifdef CONFIG_HFMODEM
 259         hfmodem_init();
 260 #endif
 261 #ifdef CONFIG_NVRAM
 262         nvram_init();
 263 #endif
 264 #ifdef CONFIG_MISC_RADIO
 265         radio_init();
 266 #endif
 267 #ifdef CONFIG_HFMODEM
 268         hfmodem_init();
 269 #endif
 270 #endif /* !MODULE */
 271         if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
 272                 printk("unable to get major %d for misc devices\n",
 273                        MISC_MAJOR);
 274                 return -EIO;
 275         }
 276
 277         return 0;
 278 }