arch/um/kernel/sigio.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/interrupt.h>
   7 #include "irq_kern.h"
   8 #include "os.h"
   9 #include "sigio.h"
  10
  11 /* Protected by sigio_lock() called from write_sigio_workaround */
  12 static int sigio_irq_fd = -1;
  13
  14 static irqreturn_t sigio_interrupt(int irq, void *data)
  15 {
  16         char c;
  17
  18         os_read_file(sigio_irq_fd, &c, sizeof(c));
  19         reactivate_fd(sigio_irq_fd, SIGIO_WRITE_IRQ);
  20         return IRQ_HANDLED;
  21 }
  22
  23 int write_sigio_irq(int fd)
  24 {
  25         int err;
  26
  27         err = um_request_irq(SIGIO_WRITE_IRQ, fd, IRQ_READ, sigio_interrupt,
  28                              IRQF_DISABLED|IRQF_SAMPLE_RANDOM, "write sigio",
  29                              NULL);
  30         if (err) {
  31                 printk(KERN_ERR "write_sigio_irq : um_request_irq failed, "
  32                        "err = %d\n", err);
  33                 return -1;
  34         }
  35         sigio_irq_fd = fd;
  36         return 0;
  37 }
  38
  39 /* These are called from os-Linux/sigio.c to protect its pollfds arrays. */
  40 static DEFINE_SPINLOCK(sigio_spinlock);
  41
  42 void sigio_lock(void)
  43 {
  44         spin_lock(&sigio_spinlock);
  45 }
  46
  47 void sigio_unlock(void)
  48 {
  49         spin_unlock(&sigio_spinlock);
  50 }