xref: /openbmc/linux/arch/um/os-Linux/irq.c (revision 861e10be)
1 /*
2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5 
6 #include <stdlib.h>
7 #include <errno.h>
8 #include <poll.h>
9 #include <signal.h>
10 #include <string.h>
11 #include <irq_user.h>
12 #include <os.h>
13 #include <um_malloc.h>
14 
15 /*
16  * Locked by irq_lock in arch/um/kernel/irq.c.  Changed by os_create_pollfd
17  * and os_free_irq_by_cb, which are called under irq_lock.
18  */
19 static struct pollfd *pollfds = NULL;
20 static int pollfds_num = 0;
21 static int pollfds_size = 0;
22 
23 int os_waiting_for_events(struct irq_fd *active_fds)
24 {
25 	struct irq_fd *irq_fd;
26 	int i, n, err;
27 
28 	n = poll(pollfds, pollfds_num, 0);
29 	if (n < 0) {
30 		err = -errno;
31 		if (errno != EINTR)
32 			printk(UM_KERN_ERR "os_waiting_for_events:"
33 			       " poll returned %d, errno = %d\n", n, errno);
34 		return err;
35 	}
36 
37 	if (n == 0)
38 		return 0;
39 
40 	irq_fd = active_fds;
41 
42 	for (i = 0; i < pollfds_num; i++) {
43 		if (pollfds[i].revents != 0) {
44 			irq_fd->current_events = pollfds[i].revents;
45 			pollfds[i].fd = -1;
46 		}
47 		irq_fd = irq_fd->next;
48 	}
49 	return n;
50 }
51 
52 int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds)
53 {
54 	if (pollfds_num == pollfds_size) {
55 		if (size_tmpfds <= pollfds_size * sizeof(pollfds[0])) {
56 			/* return min size needed for new pollfds area */
57 			return (pollfds_size + 1) * sizeof(pollfds[0]);
58 		}
59 
60 		if (pollfds != NULL) {
61 			memcpy(tmp_pfd, pollfds,
62 			       sizeof(pollfds[0]) * pollfds_size);
63 			/* remove old pollfds */
64 			kfree(pollfds);
65 		}
66 		pollfds = tmp_pfd;
67 		pollfds_size++;
68 	} else
69 		kfree(tmp_pfd);	/* remove not used tmp_pfd */
70 
71 	pollfds[pollfds_num] = ((struct pollfd) { .fd		= fd,
72 						  .events	= events,
73 						  .revents	= 0 });
74 	pollfds_num++;
75 
76 	return 0;
77 }
78 
79 void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
80 		struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2)
81 {
82 	struct irq_fd **prev;
83 	int i = 0;
84 
85 	prev = &active_fds;
86 	while (*prev != NULL) {
87 		if ((*test)(*prev, arg)) {
88 			struct irq_fd *old_fd = *prev;
89 			if ((pollfds[i].fd != -1) &&
90 			    (pollfds[i].fd != (*prev)->fd)) {
91 				printk(UM_KERN_ERR "os_free_irq_by_cb - "
92 				       "mismatch between active_fds and "
93 				       "pollfds, fd %d vs %d\n",
94 				       (*prev)->fd, pollfds[i].fd);
95 				goto out;
96 			}
97 
98 			pollfds_num--;
99 
100 			/*
101 			 * This moves the *whole* array after pollfds[i]
102 			 * (though it doesn't spot as such)!
103 			 */
104 			memmove(&pollfds[i], &pollfds[i + 1],
105 			       (pollfds_num - i) * sizeof(pollfds[0]));
106 			if (*last_irq_ptr2 == &old_fd->next)
107 				*last_irq_ptr2 = prev;
108 
109 			*prev = (*prev)->next;
110 			if (old_fd->type == IRQ_WRITE)
111 				ignore_sigio_fd(old_fd->fd);
112 			kfree(old_fd);
113 			continue;
114 		}
115 		prev = &(*prev)->next;
116 		i++;
117 	}
118  out:
119 	return;
120 }
121 
122 int os_get_pollfd(int i)
123 {
124 	return pollfds[i].fd;
125 }
126 
127 void os_set_pollfd(int i, int fd)
128 {
129 	pollfds[i].fd = fd;
130 }
131 
132 void os_set_ioignore(void)
133 {
134 	signal(SIGIO, SIG_IGN);
135 }
136