arch/um/kernel/sigio_kern.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
  16 /* Protected by sigio_lock() called from write_sigio_workaround */
  17 static int sigio_irq_fd = -1;
  18
  19 static irqreturn_t sigio_interrupt(int irq, void *data, struct pt_regs *unused)
  20 {
  21         read_sigio_fd(sigio_irq_fd);
  22         reactivate_fd(sigio_irq_fd, SIGIO_WRITE_IRQ);
  23         return(IRQ_HANDLED);
  24 }
  25
  26 int write_sigio_irq(int fd)
  27 {
  28         int err;
  29
  30         err = um_request_irq(SIGIO_WRITE_IRQ, fd, IRQ_READ, sigio_interrupt,
  31                              SA_INTERRUPT | SA_SAMPLE_RANDOM, "write sigio",
  32                              NULL);
  33         if(err){
  34                 printk("write_sigio_irq : um_request_irq failed, err = %d\n",
  35                        err);
  36                 return(-1);
  37         }
  38         sigio_irq_fd = fd;
  39         return(0);
  40 }
  41
  42 static DEFINE_SPINLOCK(sigio_spinlock);
  43
  44 void sigio_lock(void)
  45 {
  46         spin_lock(&sigio_spinlock);
  47 }
  48
  49 void sigio_unlock(void)
  50 {
  51         spin_unlock(&sigio_spinlock);
  52 }
  53
  54 /*
  55  * Overrides for Emacs so that we follow Linus's tabbing style.
  56  * Emacs will notice this stuff at the end of the file and automatically
  57  * adjust the settings for this buffer only.  This must remain at the end
  58  * of the file.
  59  * ---------------------------------------------------------------------------
  60  * Local variables:
  61  * c-file-style: "linux"
  62  * End:
  63  */