arch/um/kernel/sigio.c

   1 /*
   2  * Copyright (C) 2002 - 2003 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/kernel.h"
   7 #include "linux/list.h"
   8 #include "linux/slab.h"
   9 #include "linux/signal.h"
  10 #include "linux/interrupt.h"
  11 #include "init.h"
  12 #include "sigio.h"
  13 #include "irq_user.h"
  14 #include "irq_kern.h"
  15 #include "os.h"
  16
  17 /* Protected by sigio_lock() called from write_sigio_workaround */
  18 static int sigio_irq_fd = -1;
  19
  20 static irqreturn_t sigio_interrupt(int irq, void *data)
  21 {
  22         char c;
  23
  24         os_read_file(sigio_irq_fd, &c, sizeof(c));
  25         reactivate_fd(sigio_irq_fd, SIGIO_WRITE_IRQ);
  26         return IRQ_HANDLED;
  27 }
  28
  29 int write_sigio_irq(int fd)
  30 {
  31         int err;
  32
  33         err = um_request_irq(SIGIO_WRITE_IRQ, fd, IRQ_READ, sigio_interrupt,
  34                              IRQF_DISABLED|IRQF_SAMPLE_RANDOM, "write sigio",
  35                              NULL);
  36         if(err){
  37                 printk("write_sigio_irq : um_request_irq failed, err = %d\n",
  38                        err);
  39                 return -1;
  40         }
  41         sigio_irq_fd = fd;
  42         return 0;
  43 }
  44
  45 /* These are called from os-Linux/sigio.c to protect its pollfds arrays. */
  46 static DEFINE_SPINLOCK(sigio_spinlock);
  47
  48 void sigio_lock(void)
  49 {
  50         spin_lock(&sigio_spinlock);
  51 }
  52
  53 void sigio_unlock(void)
  54 {
  55         spin_unlock(&sigio_spinlock);
  56 }