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 extern void watchdog_init(void);
  74 extern void wdt_init(void);
  75 extern void acq_init(void);
  76 extern void dtlk_init(void);
  77 extern void pcwatchdog_init(void);
  78 extern int rtc_init(void);
  79 extern int rtc_sun_init(void);          /* Combines MK48T02 and MK48T08 */
  80 extern int rtc_DP8570A_init(void);
  81 extern int rtc_MK48T08_init(void);
  82 extern int dsp56k_init(void);
  83 extern int nvram_init(void);
  84 extern int radio_init(void);
  85 extern void hfmodem_init(void);
  86 extern int pc110pad_init(void);
  87 extern int pmu_device_init(void);
  88
  89 static int misc_read_proc(char *buf, char **start, off_t offset,
  90                           int len, int *eof, void *private)
  91 {
  92         struct miscdevice *p;
  93
  94         len=0;
  95         for (p = misc_list.next; p != &misc_list && len < 4000; p = p->next)
  96                 len += sprintf(buf+len, "%3i %s\n",p->minor, p->name ?: "");
  97         *start = buf + offset;
  98         return len > offset ? len - offset : 0;
  99 }
 100
 101
 102 static int misc_open(struct inode * inode, struct file * file)
 103 {
 104         int minor = MINOR(inode->i_rdev);
 105         struct miscdevice *c = misc_list.next;
 106         file->f_op = NULL;
 107
 108         while ((c != &misc_list) && (c->minor != minor))
 109                 c = c->next;
 110         if (c == &misc_list) {
 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                         return -ENODEV;
 119         }
 120
 121         if ((file->f_op = c->fops) && file->f_op->open)
 122                 return file->f_op->open(inode,file);
 123         else
 124                 return -ENODEV;
 125 }
 126
 127 static struct file_operations misc_fops = {
 128         NULL,           /* seek */
 129         NULL,           /* read */
 130         NULL,           /* write */
 131         NULL,           /* readdir */
 132         NULL,           /* poll */
 133         NULL,           /* ioctl */
 134         NULL,           /* mmap */
 135         misc_open,
 136         NULL,           /* flush */
 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
 155         /*
 156          * Add it to the front, so that later devices can "override"
 157          * earlier defaults
 158          */
 159         misc->prev = &misc_list;
 160         misc->next = misc_list.next;
 161         misc->prev->next = misc;
 162         misc->next->prev = misc;
 163         return 0;
 164 }
 165
 166 int misc_deregister(struct miscdevice * misc)
 167 {
 168         int i = misc->minor;
 169         if (!misc->next || !misc->prev)
 170                 return -EINVAL;
 171         misc->prev->next = misc->next;
 172         misc->next->prev = misc->prev;
 173         misc->next = NULL;
 174         misc->prev = NULL;
 175         if (i < DYNAMIC_MINORS && i>0) {
 176                 misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
 177         }
 178         return 0;
 179 }
 180
 181 EXPORT_SYMBOL(misc_register);
 182 EXPORT_SYMBOL(misc_deregister);
 183
 184 static struct proc_dir_entry *proc_misc;
 185
 186 int __init misc_init(void)
 187 {
 188         proc_misc = create_proc_entry("misc", 0, 0);
 189         if (proc_misc)
 190                 proc_misc->read_proc = misc_read_proc;
 191 #ifdef CONFIG_BUSMOUSE
 192         bus_mouse_init();
 193 #endif
 194 #if defined CONFIG_82C710_MOUSE
 195         qpmouse_init();
 196 #endif
 197 #ifdef CONFIG_MS_BUSMOUSE
 198         ms_bus_mouse_init();
 199 #endif
 200 #ifdef CONFIG_ATIXL_BUSMOUSE
 201         atixl_busmouse_init();
 202 #endif
 203 #ifdef CONFIG_AMIGAMOUSE
 204         amiga_mouse_init();
 205 #endif
 206 #ifdef CONFIG_ATARIMOUSE
 207         atari_mouse_init();
 208 #endif
 209 #ifdef CONFIG_SUN_MOUSE
 210         sun_mouse_init();
 211 #endif
 212 #ifdef CONFIG_ADBMOUSE
 213         adb_mouse_init();
 214 #endif
 215 #ifdef CONFIG_PC110_PAD
 216         pc110pad_init();
 217 #endif
 218 /*
 219  *      Only one watchdog can succeed. We probe the pcwatchdog first,
 220  *      then the wdt cards and finally the software watchdog which always
 221  *      works. This means if your hardware watchdog dies or is 'borrowed'
 222  *      for some reason the software watchdog still gives you some cover.
 223  */
 224 #ifdef CONFIG_PCWATCHDOG
 225         pcwatchdog_init();
 226 #endif
 227 #ifdef CONFIG_WDT
 228         wdt_init();
 229 #endif
 230 #ifdef CONFIG_ACQUIRE_WDT
 231         acq_init();
 232 #endif
 233 #ifdef CONFIG_SOFT_WATCHDOG
 234         watchdog_init();
 235 #endif
 236 #ifdef CONFIG_DTLK
 237         dtlk_init();
 238 #endif
 239 #ifdef CONFIG_APM
 240         apm_bios_init();
 241 #endif
 242 #ifdef CONFIG_H8
 243         h8_init();
 244 #endif
 245 #ifdef CONFIG_MVME16x
 246         rtc_MK48T08_init();
 247 #endif
 248 #ifdef CONFIG_BVME6000
 249         rtc_DP8570A_init();
 250 #endif
 251 #if defined(CONFIG_SUN_MOSTEK_RTC)
 252         rtc_sun_init();
 253 #endif
 254 #if defined(CONFIG_RTC)
 255         rtc_init();
 256 #endif
 257 #ifdef CONFIG_ATARI_DSP56K
 258         dsp56k_init();
 259 #endif
 260 #ifdef CONFIG_HFMODEM
 261         hfmodem_init();
 262 #endif
 263 #ifdef CONFIG_NVRAM
 264         nvram_init();
 265 #endif
 266 #ifdef CONFIG_MISC_RADIO
 267         radio_init();
 268 #endif
 269 #ifdef CONFIG_HFMODEM
 270         hfmodem_init();
 271 #endif
 272 #ifdef CONFIG_PMAC_PBOOK
 273         pmu_device_init();
 274 #endif
 275         if (register_chrdev(MISC_MAJOR,"misc",&misc_fops)) {
 276                 printk("unable to get major %d for misc devices\n",
 277                        MISC_MAJOR);
 278                 return -EIO;
 279         }
 280
 281         return 0;
 282 }