xref: /openbmc/linux/arch/um/kernel/sigio.c (revision a2cce7a9)
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 }
50