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                              0, "write sigio", NULL);
  29         if (err) {
  30                 printk(KERN_ERR "write_sigio_irq : um_request_irq failed, "
  31                        "err = %d\n", err);
  32                 return -1;
  33         }
  34         sigio_irq_fd = fd;
  35         return 0;
  36 }
  37
  38 /* These are called from os-Linux/sigio.c to protect its pollfds arrays. */
  39 static DEFINE_SPINLOCK(sigio_spinlock);
  40
  41 void sigio_lock(void)
  42 {
  43         spin_lock(&sigio_spinlock);
  44 }
  45
  46 void sigio_unlock(void)
  47 {
  48         spin_unlock(&sigio_spinlock);
  49 }