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/module.h>
  35 #include <linux/config.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 #include <linux/kmod.h>
  53
  54 /*
  55  * Head entry for the doubly linked miscdevice list
  56  */
  57 static struct miscdevice misc_list = { 0, "head", NULL, &misc_list, &misc_list };
  58
  59 /*
  60  * Assigned numbers, used for dynamic minors
  61  */
  62 #define DYNAMIC_MINORS 64 /* like dynamic majors */
  63 static unsigned char misc_minors[DYNAMIC_MINORS / 8];
  64
  65 extern int bus_mouse_init(void);
  66 extern int qpmouse_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 int adb_mouse_init(void);
  73 #ifdef CONFIG_SGI_NEWPORT_GFX
  74 extern void gfx_register(void);
  75 #endif
  76 extern void streamable_init(void);
  77 extern void watchdog_init(void);
  78 extern void wdt_init(void);
  79 extern void acq_init(void);
  80 extern void dtlk_init(void);
  81 extern void pcwatchdog_init(void);
  82 extern int rtc_init(void);
  83 extern int rtc_sun_init(void);          /* Combines MK48T02 and MK48T08 */
  84 extern int rtc_DP8570A_init(void);
  85 extern int rtc_MK48T08_init(void);
  86 extern int dsp56k_init(void);
  87 extern int nvram_init(void);
  88 extern int radio_init(void);
  89 extern void hfmodem_init(void);
  90 extern int pc110pad_init(void);
  91 extern int pmu_device_init(void);
  92
  93 static int misc_read_proc(char *buf, char **start, off_t offset,
  94                           int len, int *eof, void *private)
  95 {
  96         struct miscdevice *p;
  97
  98         len=0;
  99         for (p = misc_list.next; p != &misc_list && len < 4000; p = p->next)
 100                 len += sprintf(buf+len, "%3i %s\n",p->minor, p->name ?: "");
 101         *start = buf + offset;
 102         return len > offset ? len - offset : 0;
 103 }
 104
 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                 char modname[20];
 116                 sprintf(modname, "char-major-%d-%d", MISC_MAJOR, minor);
 117                 request_module(modname);
 118                 c = misc_list.next;
 119                 while ((c != &misc_list) && (c->minor != minor))
 120                         c = c->next;
 121                 if (c == &misc_list)
 122                         return -ENODEV;
 123         }
 124
 125         if ((file->f_op = c->fops) && file->f_op->open)
 126                 return file->f_op->open(inode,file);
 127         else
 128                 return -ENODEV;
 129 }
 130
 131 static struct file_operations misc_fops = {
 132         NULL,           /* seek */
 133         NULL,           /* read */
 134         NULL,           /* write */
 135         NULL,           /* readdir */
 136         NULL,           /* poll */
 137         NULL,           /* ioctl */
 138         NULL,           /* mmap */
 139         misc_open,
 140         NULL,           /* flush */
 141         NULL            /* release */
 142 };
 143
 144 int misc_register(struct miscdevice * misc)
 145 {
 146         if (misc->next || misc->prev)
 147                 return -EBUSY;
 148         if (misc->minor == MISC_DYNAMIC_MINOR) {
 149                 int i = DYNAMIC_MINORS;
 150                 while (--i >= 0)
 151                         if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
 152                                 break;
 153                 if (i<0) return -EBUSY;
 154                 misc->minor = i;
 155         }
 156         if (misc->minor < DYNAMIC_MINORS)
 157                 misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
 158
 159         /*
 160          * Add it to the front, so that later devices can "override"
 161          * earlier defaults
 162          */
 163         misc->prev = &misc_list;
 164         misc->next = misc_list.next;
 165         misc->prev->next = misc;
 166         misc->next->prev = misc;
 167         return 0;
 168 }
 169
 170 int misc_deregister(struct miscdevice * misc)
 171 {
 172         int i = misc->minor;
 173         if (!misc->next || !misc->prev)
 174                 return -EINVAL;
 175         misc->prev->next = misc->next;
 176         misc->next->prev = misc->prev;
 177         misc->next = NULL;
 178         misc->prev = NULL;
 179         if (i < DYNAMIC_MINORS && i>0) {
 180                 misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
 181         }
 182         return 0;
 183 }
 184
 185 EXPORT_SYMBOL(misc_register);
 186 EXPORT_SYMBOL(misc_deregister);
 187
 188 static struct proc_dir_entry *proc_misc;
 189
 190 int __init misc_init(void)
 191 {
 192         proc_misc = create_proc_entry("misc", 0, 0);
 193         if (proc_misc)
 194                 proc_misc->read_proc = misc_read_proc;
 195 #ifdef CONFIG_BUSMOUSE
 196         bus_mouse_init();
 197 #endif
 198 #if defined CONFIG_82C710_MOUSE
 199         qpmouse_init();
 200 #endif
 201 #ifdef CONFIG_MS_BUSMOUSE
 202         ms_bus_mouse_init();
 203 #endif
 204 #ifdef CONFIG_ATIXL_BUSMOUSE
 205         atixl_busmouse_init();
 206 #endif
 207 #ifdef CONFIG_AMIGAMOUSE
 208         amiga_mouse_init();
 209 #endif
 210 #ifdef CONFIG_ATARIMOUSE
 211         atari_mouse_init();
 212 #endif
 213 #ifdef CONFIG_SUN_MOUSE
 214         sun_mouse_init();
 215 #endif
 216 #ifdef CONFIG_ADBMOUSE
 217         adb_mouse_init();
 218 #endif
 219 #ifdef CONFIG_PC110_PAD
 220         pc110pad_init();
 221 #endif
 222 /*
 223  *      Only one watchdog can succeed. We probe the pcwatchdog first,
 224  *      then the wdt cards and finally the software watchdog which always
 225  *      works. This means if your hardware watchdog dies or is 'borrowed'
 226  *      for some reason the software watchdog still gives you some cover.
 227  */
 228 #ifdef CONFIG_PCWATCHDOG
 229         pcwatchdog_init();
 230 #endif
 231 #ifdef CONFIG_WDT
 232         wdt_init();
 233 #endif
 234 #ifdef CONFIG_ACQUIRE_WDT
 235         acq_init();
 236 #endif
 237 #ifdef CONFIG_SOFT_WATCHDOG
 238         watchdog_init();
 239 #endif
 240 #ifdef CONFIG_DTLK
 241         dtlk_init();
 242 #endif
 243 #ifdef CONFIG_APM
 244         apm_bios_init();
 245 #endif
 246 #ifdef CONFIG_H8
 247         h8_init();
 248 #endif
 249 #ifdef CONFIG_MVME16x
 250         rtc_MK48T08_init();
 251 #endif
 252 #ifdef CONFIG_BVME6000
 253         rtc_DP8570A_init();
 254 #endif
 255 #if defined(CONFIG_SUN_MOSTEK_RTC)
 256         rtc_sun_init();
 257 #endif
 258 #if defined(CONFIG_RTC)
 259         rtc_init();
 260 #endif
 261 #ifdef CONFIG_ATARI_DSP56K
 262         dsp56k_init();
 263 #endif
 264 #ifdef CONFIG_HFMODEM
 265         hfmodem_init();
 266 #endif
 267 #ifdef CONFIG_NVRAM
 268         nvram_init();
 269 #endif
 270 #ifdef CONFIG_MISC_RADIO
 271         radio_init();
 272 #endif
 273 #ifdef CONFIG_HFMODEM
 274         hfmodem_init();
 275 #endif
 276 #ifdef CONFIG_PMAC_PBOOK
 277         pmu_device_init();
 278 #endif
 279 #ifdef CONFIG_SGI_NEWPORT_GFX
 280         gfx_register ();
 281 #endif
 282 #ifdef CONFIG_SGI
 283         streamable_init ();
 284 #endif
 285         if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
 286                 printk("unable to get major %d for misc devices\n",
 287                        MISC_MAJOR);
 288                 return -EIO;
 289         }
 290
 291         return 0;
 292 }