drivers/sgi/char/shmiq.c

   1 /* $Id: shmiq.c,v 1.12 1999/06/17 13:29:04 ralf Exp $
   2  *
   3  * shmiq.c: shared memory input queue driver
   4  * written 1997 Miguel de Icaza (miguel@nuclecu.unam.mx)
   5  *
   6  * We implement /dev/shmiq, /dev/qcntlN here
   7  * this is different from IRIX that has shmiq as a misc
   8  * streams device and the and qcntl devices as a major device.
   9  *
  10  * minor number 0 implements /dev/shmiq,
  11  * any other number implements /dev/qcntl${minor-1}
  12  *
  13  * /dev/shmiq is used by the X server for two things:
  14  *
  15  *    1. for I_LINK()ing trough ioctl the file handle of a
  16  *       STREAMS device.
  17  *
  18  *    2. To send STREAMS-commands to the devices with the
  19  *       QIO ioctl interface.
  20  *
  21  * I have not yet figured how to make multiple X servers share
  22  * /dev/shmiq for having different servers running.  So, for now
  23  * I keep a kernel-global array of inodes that are pushed into
  24  * /dev/shmiq.
  25  *
  26  * /dev/qcntlN is used by the X server for two things:
  27  *
  28  *    1. Issuing the QIOCATTACH for mapping the shared input
  29  *       queue into the address space of the X server (yeah, yeah,
  30  *       I did not invent this interface).
  31  *
  32  *    2. used by select.  I bet it is used for checking for events on
  33  *       the queue.
  34  *
  35  * Now the problem is that there does not seem anything that
  36  * establishes a connection between /dev/shmiq and the qcntlN file.  I
  37  * need an strace from an X server that runs on a machine with more
  38  * than one keyboard.  And this is a problem since the file handles
  39  * are pushed in /dev/shmiq, while the events should be dispatched to
  40  * the /dev/qcntlN device.
  41  *
  42  * Until then, I just allow for 1 qcntl device.
  43  *
  44  */
  45
  46 #include <linux/fs.h>
  47 #include <linux/miscdevice.h>
  48 #include <linux/sched.h>
  49 #include <linux/file.h>
  50 #include <linux/interrupt.h>
  51 #include <linux/poll.h>
  52 #include <linux/vmalloc.h>
  53 #include <linux/wait.h>
  54 #include <linux/major.h>
  55 #include <linux/smp_lock.h>
  56
  57 #include <asm/shmiq.h>
  58 #include <asm/mman.h>
  59 #include <asm/uaccess.h>
  60 #include <asm/poll.h>
  61 #include "graphics.h"
  62
  63 /* we are not really getting any more than a few files in the shmiq */
  64 #define MAX_SHMIQ_DEVS 10
  65
  66 /*
  67  * One per X server running, not going to get very big.
  68  * Even if we have this we now assume just 1 /dev/qcntl can be
  69  * active, I need to find how this works on multi-headed machines.
  70  */
  71 #define MAX_SHMI_QUEUES 4
  72
  73 static struct {
  74         int                 used;
  75         struct file         *filp;
  76         struct shmiqsetcpos cpos;
  77 } shmiq_pushed_devices [MAX_SHMIQ_DEVS];
  78
  79 /* /dev/qcntlN attached memory regions, location and size of the event queue */
  80 static struct {
  81         int    opened;          /* if this device has been opened */
  82         void   *shmiq_vaddr;    /* mapping in kernel-land */
  83         int    tail;            /* our copy of the shmiq->tail */
  84         int    events;
  85         int    mapped;
  86
  87         wait_queue_head_t    proc_list;
  88         struct fasync_struct *fasync;
  89 } shmiqs [MAX_SHMI_QUEUES];
  90
  91 void
  92 shmiq_push_event (struct shmqevent *e)
  93 {
  94         struct sharedMemoryInputQueue *s;
  95         int    device = 0;      /* FIXME: here is the assumption /dev/shmiq == /dev/qcntl0 */
  96         int    tail_next;
  97
  98         if (!shmiqs [device].mapped)
  99                 return;
 100         s = shmiqs [device].shmiq_vaddr;
 101
 102         s->flags = 0;
 103         if (s->tail != shmiqs [device].tail){
 104                 s->flags |= SHMIQ_CORRUPTED;
 105                 return;
 106         }
 107         tail_next = (s->tail + 1) % (shmiqs [device].events);
 108
 109         if (tail_next == s->head){
 110                 s->flags |= SHMIQ_OVERFLOW;
 111                 return;
 112         }
 113
 114         e->un.time = jiffies;
 115         s->events [s->tail] = *e;
 116         printk ("KERNEL: dev=%d which=%d type=%d flags=%d\n",
 117                 e->data.device, e->data.which, e->data.type, e->data.flags);
 118         s->tail = tail_next;
 119         shmiqs [device].tail = tail_next;
 120         if (shmiqs [device].fasync)
 121                 kill_fasync (shmiqs [device].fasync, SIGIO);
 122         wake_up_interruptible (&shmiqs [device].proc_list);
 123 }
 124
 125 static int
 126 shmiq_manage_file (struct file *filp)
 127 {
 128         int i;
 129
 130         if (!filp->f_op || !filp->f_op->ioctl)
 131                 return -ENOSR;
 132
 133         for (i = 0; i < MAX_SHMIQ_DEVS; i++){
 134                 if (shmiq_pushed_devices [i].used)
 135                         continue;
 136                 if ((*filp->f_op->ioctl)(filp->f_dentry->d_inode, filp, SHMIQ_ON, i) != 0)
 137                         return -ENOSR;
 138                 shmiq_pushed_devices [i].used = 1;
 139                 shmiq_pushed_devices [i].filp = filp;
 140                 shmiq_pushed_devices [i].cpos.x = 0;
 141                 shmiq_pushed_devices [i].cpos.y = 0;
 142                 return i;
 143         }
 144         return -ENOSR;
 145 }
 146
 147 static int
 148 shmiq_forget_file (unsigned long fdes)
 149 {
 150         struct file *filp;
 151
 152         if (fdes > MAX_SHMIQ_DEVS)
 153                 return -EINVAL;
 154
 155         if (!shmiq_pushed_devices [fdes].used)
 156                 return -EINVAL;
 157
 158         filp = shmiq_pushed_devices [fdes].filp;
 159         if (filp){
 160                 (*filp->f_op->ioctl)(filp->f_dentry->d_inode, filp, SHMIQ_OFF, 0);
 161                 shmiq_pushed_devices [fdes].filp = 0;
 162                 fput (filp);
 163         }
 164         shmiq_pushed_devices [fdes].used = 0;
 165
 166         return 0;
 167 }
 168
 169 static int
 170 shmiq_sioc (int device, int cmd, struct strioctl *s)
 171 {
 172         switch (cmd){
 173         case QIOCGETINDX:
 174                 /*
 175                  * Ok, we just return the index they are providing us
 176                  */
 177                 printk ("QIOCGETINDX: returning %d\n", *(int *)s->ic_dp);
 178                 return 0;
 179
 180         case QIOCIISTR: {
 181                 struct muxioctl *mux = (struct muxioctl *) s->ic_dp;
 182
 183                 printk ("Double indirect ioctl: [%d, %x\n", mux->index, mux->realcmd);
 184                 return -EINVAL;
 185         }
 186
 187         case QIOCSETCPOS: {
 188                 if (copy_from_user (&shmiq_pushed_devices [device].cpos, s->ic_dp,
 189                                     sizeof (struct shmiqsetcpos)))
 190                         return -EFAULT;
 191                 return 0;
 192         }
 193         }
 194         printk ("Unknown I_STR request for shmiq device: 0x%x\n", cmd);
 195         return -EINVAL;
 196 }
 197
 198 static int
 199 shmiq_ioctl (struct inode *inode, struct file *f, unsigned int cmd, unsigned long arg)
 200 {
 201         struct file *file;
 202         struct strioctl sioc;
 203         int v;
 204
 205         switch (cmd){
 206                 /*
 207                  * They are giving us the file descriptor for one
 208                  * of their streams devices
 209                  */
 210
 211         case I_LINK:
 212                 file = fget (arg);
 213                 if (!file)
 214                         goto bad_file;
 215
 216                 v = shmiq_manage_file (file);
 217                 return v;
 218
 219                 /*
 220                  * Remove a device from our list of managed
 221                  * stream devices
 222                  */
 223         case I_UNLINK:
 224                 v = shmiq_forget_file (arg);
 225                 return v;
 226
 227         case I_STR:
 228                 v = get_sioc (&sioc, arg);
 229                 if (v)
 230                         return v;
 231
 232                 /* FIXME: This forces device = 0 */
 233                 return shmiq_sioc (0, sioc.ic_cmd, &sioc);
 234         }
 235
 236         return -EINVAL;
 237 bad_file:
 238         unlock_kernel ();
 239         return -EBADF;
 240 }
 241
 242 extern int sys_munmap(unsigned long addr, size_t len);
 243
 244 static int
 245 qcntl_ioctl (struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg, int minor)
 246 {
 247         struct shmiqreq req;
 248         struct vm_area_struct *vma;
 249         int v;
 250
 251         switch (cmd){
 252                 /*
 253                  * The address space is already mapped as a /dev/zero
 254                  * mapping.  FIXME: check that /dev/zero is what the user
 255                  * had mapped before :-)
 256                  */
 257         case QIOCATTACH: {
 258                 unsigned long vaddr;
 259                 int s;
 260
 261                 v = verify_area (VERIFY_READ, (void *) arg, sizeof (struct shmiqreq));
 262                 if (v)
 263                         return v;
 264                 if (copy_from_user (&req, (void *) arg, sizeof (req)))
 265                         return -EFAULT;
 266                 /* Do not allow to attach to another region if it has been already attached */
 267                 if (shmiqs [minor].mapped){
 268                         printk ("SHMIQ:The thingie is already mapped\n");
 269                         return -EINVAL;
 270                 }
 271
 272                 vaddr = (unsigned long) req.user_vaddr;
 273                 vma = find_vma (current->mm, vaddr);
 274                 if (!vma){
 275                         printk ("SHMIQ: could not find %lx the vma\n", vaddr);
 276                         return -EINVAL;
 277                 }
 278                 s = req.arg * sizeof (struct shmqevent) + sizeof (struct sharedMemoryInputQueue);
 279                 v = sys_munmap (vaddr, s);
 280                 do_mmap (filp, vaddr, s, PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 0);
 281                 shmiqs [minor].events = req.arg;
 282                 shmiqs [minor].mapped = 1;
 283                 return 0;
 284         }
 285         }
 286         return -EINVAL;
 287 }
 288
 289 unsigned long
 290 shmiq_nopage (struct vm_area_struct *vma, unsigned long address, int write_access)
 291 {
 292         /* Do not allow for mremap to expand us */
 293         return 0;
 294 }
 295
 296 static struct vm_operations_struct qcntl_mmap = {
 297         NULL,                   /* no special mmap-open */
 298         NULL,                   /* no special mmap-close */
 299         NULL,                   /* no special mmap-unmap */
 300         NULL,                   /* no special mmap-protect */
 301         NULL,                   /* no special mmap-sync */
 302         NULL,                   /* no special mmap-advise */
 303         shmiq_nopage,           /* our magic no-page fault handler */
 304         NULL,                   /* no special mmap-wppage */
 305         NULL,                   /* no special mmap-swapout */
 306         NULL                    /* no special mmap-swapin */
 307 };
 308
 309 static int
 310 shmiq_qcntl_mmap (struct file *file, struct vm_area_struct *vma)
 311 {
 312         int           minor = MINOR (file->f_dentry->d_inode->i_rdev), error;
 313         unsigned int  size;
 314         unsigned long mem, start;
 315
 316         /* mmap is only supported on the qcntl devices */
 317         if (minor-- == 0)
 318                 return -EINVAL;
 319
 320         if (vma->vm_offset != 0)
 321                 return -EINVAL;
 322
 323         size  = vma->vm_end - vma->vm_start;
 324         start = vma->vm_start;
 325         mem = (unsigned long) shmiqs [minor].shmiq_vaddr =  vmalloc_uncached (size);
 326         if (!mem)
 327                 return -EINVAL;
 328
 329         /* Prevent the swapper from considering these pages for swap and touching them */
 330         vma->vm_flags    |= (VM_SHM  | VM_LOCKED | VM_IO);
 331         vma->vm_ops = &qcntl_mmap;
 332
 333         /* Uncache the pages */
 334         vma->vm_page_prot = PAGE_USERIO;
 335
 336         error = vmap_page_range (vma->vm_start, size, mem);
 337
 338         shmiqs [minor].tail = 0;
 339         /* Init the shared memory input queue */
 340         memset (shmiqs [minor].shmiq_vaddr, 0, size);
 341
 342         return error;
 343 }
 344
 345 static int
 346 shmiq_qcntl_ioctl (struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
 347 {
 348         int minor = MINOR (inode->i_rdev);
 349
 350         lock_kernel ();
 351
 352         if (minor-- == 0)
 353                 return shmiq_ioctl (inode, filp, cmd, arg);
 354
 355         return qcntl_ioctl (inode, filp, cmd, arg, minor);
 356 }
 357
 358 static unsigned int
 359 shmiq_qcntl_poll (struct file *filp, poll_table *wait)
 360 {
 361         struct sharedMemoryInputQueue *s;
 362         int minor = MINOR (filp->f_dentry->d_inode->i_rdev);
 363
 364         if (minor-- == 0)
 365                 return 0;
 366
 367         if (!shmiqs [minor].mapped)
 368                 return 0;
 369
 370         poll_wait (filp, &shmiqs [minor].proc_list, wait);
 371         s = shmiqs [minor].shmiq_vaddr;
 372         if (s->head != s->tail)
 373                 return POLLIN | POLLRDNORM;
 374         return 0;
 375 }
 376
 377 static int
 378 shmiq_qcntl_open (struct inode *inode, struct file *filp)
 379 {
 380         int minor = MINOR (inode->i_rdev);
 381
 382         if (minor == 0)
 383                 return 0;
 384
 385         minor--;
 386         if (minor > MAX_SHMI_QUEUES)
 387                 return -EINVAL;
 388         if (shmiqs [minor].opened)
 389                 return -EBUSY;
 390
 391         lock_kernel ();
 392         shmiqs [minor].opened      = 1;
 393         shmiqs [minor].shmiq_vaddr = 0;
 394         unlock_kernel ();
 395         return 0;
 396 }
 397
 398 static int
 399 shmiq_qcntl_fasync (int fd, struct file *file, int on)
 400 {
 401         int retval;
 402         int minor = MINOR (file->f_dentry->d_inode->i_rdev);
 403
 404         retval = fasync_helper (fd, file, on, &shmiqs [minor].fasync);
 405         if (retval < 0)
 406                 return retval;
 407         return 0;
 408 }
 409
 410 static int
 411 shmiq_qcntl_close (struct inode *inode, struct file *filp)
 412 {
 413         int minor = MINOR (inode->i_rdev);
 414         int j;
 415
 416         if (minor-- == 0){
 417                 for (j = 0; j < MAX_SHMIQ_DEVS; j++)
 418                         shmiq_forget_file (j);
 419         }
 420
 421         if (minor > MAX_SHMI_QUEUES)
 422                 return -EINVAL;
 423         if (shmiqs [minor].opened == 0)
 424                 return -EINVAL;
 425
 426         lock_kernel ();
 427         shmiq_qcntl_fasync (-1, filp, 0);
 428         shmiqs [minor].opened      = 0;
 429         shmiqs [minor].mapped      = 0;
 430         shmiqs [minor].events      = 0;
 431         shmiqs [minor].fasync      = 0;
 432         vfree (shmiqs [minor].shmiq_vaddr);
 433         shmiqs [minor].shmiq_vaddr = 0;
 434         unlock_kernel ();
 435         return 0;
 436 }
 437
 438
 439 static struct
 440 file_operations shmiq_fops =
 441 {
 442         NULL,                   /* seek */
 443         NULL,                   /* read */
 444         NULL,                   /* write */
 445         NULL,                   /* readdir */
 446         shmiq_qcntl_poll,       /* poll */
 447         shmiq_qcntl_ioctl,      /* ioctl */
 448         shmiq_qcntl_mmap,       /* mmap */
 449         shmiq_qcntl_open,       /* open */
 450         NULL,                   /* flush */
 451         shmiq_qcntl_close,      /* close */
 452         NULL,                   /* fsync */
 453         shmiq_qcntl_fasync,     /* fasync */
 454         NULL,                   /* check_media_change */
 455         NULL,                   /* revalidate */
 456 };
 457
 458 void
 459 shmiq_init (void)
 460 {
 461         printk ("SHMIQ setup\n");
 462         register_chrdev (SHMIQ_MAJOR, "shmiq", &shmiq_fops);
 463 }