Merge with /home/shaggy/git/linus-clean/
[linux-2.6] / arch / um / kernel / irq_user.c
1 /* 
2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include <signal.h>
10 #include <string.h>
11 #include <sys/poll.h>
12 #include <sys/types.h>
13 #include <sys/time.h>
14 #include "user_util.h"
15 #include "kern_util.h"
16 #include "user.h"
17 #include "process.h"
18 #include "signal_user.h"
19 #include "sigio.h"
20 #include "irq_user.h"
21 #include "os.h"
22
23 struct irq_fd {
24         struct irq_fd *next;
25         void *id;
26         int fd;
27         int type;
28         int irq;
29         int pid;
30         int events;
31         int current_events;
32         int freed;
33 };
34
35 static struct irq_fd *active_fds = NULL;
36 static struct irq_fd **last_irq_ptr = &active_fds;
37
38 static struct pollfd *pollfds = NULL;
39 static int pollfds_num = 0;
40 static int pollfds_size = 0;
41
42 extern int io_count, intr_count;
43
44 void sigio_handler(int sig, union uml_pt_regs *regs)
45 {
46         struct irq_fd *irq_fd, *next;
47         int i, n;
48
49         if(smp_sigio_handler()) return;
50         while(1){
51                 n = poll(pollfds, pollfds_num, 0);
52                 if(n < 0){
53                         if(errno == EINTR) continue;
54                         printk("sigio_handler : poll returned %d, "
55                                "errno = %d\n", n, errno);
56                         break;
57                 }
58                 if(n == 0) break;
59
60                 irq_fd = active_fds;
61                 for(i = 0; i < pollfds_num; i++){
62                         if(pollfds[i].revents != 0){
63                                 irq_fd->current_events = pollfds[i].revents;
64                                 pollfds[i].fd = -1;
65                         }
66                         irq_fd = irq_fd->next;
67                 }
68
69                 for(irq_fd = active_fds; irq_fd != NULL; irq_fd = next){
70                         next = irq_fd->next;
71                         if(irq_fd->current_events != 0){
72                                 irq_fd->current_events = 0;
73                                 do_IRQ(irq_fd->irq, regs);
74
75                                 /* This is here because the next irq may be
76                                  * freed in the handler.  If a console goes
77                                  * away, both the read and write irqs will be
78                                  * freed.  After do_IRQ, ->next will point to
79                                  * a good IRQ.
80                                  * Irqs can't be freed inside their handlers,
81                                  * so the next best thing is to have them
82                                  * marked as needing freeing, so that they
83                                  * can be freed here.
84                                  */
85                                 next = irq_fd->next;
86                                 if(irq_fd->freed){
87                                         free_irq(irq_fd->irq, irq_fd->id);
88                                         free_irq_by_irq_and_dev(irq_fd->irq,
89                                                                 irq_fd->id);
90                                 }
91                         }
92                 }
93         }
94 }
95
96 int activate_ipi(int fd, int pid)
97 {
98         return(os_set_fd_async(fd, pid));
99 }
100
101 static void maybe_sigio_broken(int fd, int type)
102 {
103         if(isatty(fd)){
104                 if((type == IRQ_WRITE) && !pty_output_sigio){
105                         write_sigio_workaround();
106                         add_sigio_fd(fd, 0);
107                 }
108                 else if((type == IRQ_READ) && !pty_close_sigio){
109                         write_sigio_workaround();
110                         add_sigio_fd(fd, 1);                    
111                 }
112         }
113 }
114
115 int activate_fd(int irq, int fd, int type, void *dev_id)
116 {
117         struct pollfd *tmp_pfd;
118         struct irq_fd *new_fd, *irq_fd;
119         unsigned long flags;
120         int pid, events, err, n, size;
121
122         pid = os_getpid();
123         err = os_set_fd_async(fd, pid);
124         if(err < 0)
125                 goto out;
126
127         new_fd = um_kmalloc(sizeof(*new_fd));
128         err = -ENOMEM;
129         if(new_fd == NULL)
130                 goto out;
131
132         if(type == IRQ_READ) events = POLLIN | POLLPRI;
133         else events = POLLOUT;
134         *new_fd = ((struct irq_fd) { .next              = NULL,
135                                      .id                = dev_id,
136                                      .fd                = fd,
137                                      .type              = type,
138                                      .irq               = irq,
139                                      .pid               = pid,
140                                      .events            = events,
141                                      .current_events    = 0,
142                                      .freed             = 0  } );
143
144         /* Critical section - locked by a spinlock because this stuff can
145          * be changed from interrupt handlers.  The stuff above is done 
146          * outside the lock because it allocates memory.
147          */
148
149         /* Actually, it only looks like it can be called from interrupt
150          * context.  The culprit is reactivate_fd, which calls 
151          * maybe_sigio_broken, which calls write_sigio_workaround,
152          * which calls activate_fd.  However, write_sigio_workaround should
153          * only be called once, at boot time.  That would make it clear that
154          * this is called only from process context, and can be locked with
155          * a semaphore.
156          */
157         flags = irq_lock();
158         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
159                 if((irq_fd->fd == fd) && (irq_fd->type == type)){
160                         printk("Registering fd %d twice\n", fd);
161                         printk("Irqs : %d, %d\n", irq_fd->irq, irq);
162                         printk("Ids : 0x%x, 0x%x\n", irq_fd->id, dev_id);
163                         goto out_unlock;
164                 }
165         }
166
167         n = pollfds_num;
168         if(n == pollfds_size){
169                 while(1){
170                         /* Here we have to drop the lock in order to call 
171                          * kmalloc, which might sleep.  If something else
172                          * came in and changed the pollfds array, we free
173                          * the buffer and try again.
174                          */
175                         irq_unlock(flags);
176                         size = (pollfds_num + 1) * sizeof(pollfds[0]);
177                         tmp_pfd = um_kmalloc(size);
178                         flags = irq_lock();
179                         if(tmp_pfd == NULL)
180                                 goto out_unlock;
181                         if(n == pollfds_size)
182                                 break;
183                         kfree(tmp_pfd);
184                 }
185                 if(pollfds != NULL){
186                         memcpy(tmp_pfd, pollfds,
187                                sizeof(pollfds[0]) * pollfds_size);
188                         kfree(pollfds);
189                 }
190                 pollfds = tmp_pfd;
191                 pollfds_size++;
192         }
193
194         if(type == IRQ_WRITE) 
195                 fd = -1;
196
197         pollfds[pollfds_num] = ((struct pollfd) { .fd   = fd,
198                                                   .events       = events,
199                                                   .revents      = 0 });
200         pollfds_num++;
201
202         *last_irq_ptr = new_fd;
203         last_irq_ptr = &new_fd->next;
204
205         irq_unlock(flags);
206
207         /* This calls activate_fd, so it has to be outside the critical
208          * section.
209          */
210         maybe_sigio_broken(fd, type);
211
212         return(0);
213
214  out_unlock:
215         irq_unlock(flags);
216         kfree(new_fd);
217  out:
218         return(err);
219 }
220
221 static void free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg)
222 {
223         struct irq_fd **prev;
224         unsigned long flags;
225         int i = 0;
226
227         flags = irq_lock();
228         prev = &active_fds;
229         while(*prev != NULL){
230                 if((*test)(*prev, arg)){
231                         struct irq_fd *old_fd = *prev;
232                         if((pollfds[i].fd != -1) && 
233                            (pollfds[i].fd != (*prev)->fd)){
234                                 printk("free_irq_by_cb - mismatch between "
235                                        "active_fds and pollfds, fd %d vs %d\n",
236                                        (*prev)->fd, pollfds[i].fd);
237                                 goto out;
238                         }
239
240                         pollfds_num--;
241
242                         /* This moves the *whole* array after pollfds[i] (though
243                          * it doesn't spot as such)! */
244
245                         memmove(&pollfds[i], &pollfds[i + 1],
246                                (pollfds_num - i) * sizeof(pollfds[0]));
247
248                         if(last_irq_ptr == &old_fd->next) 
249                                 last_irq_ptr = prev;
250                         *prev = (*prev)->next;
251                         if(old_fd->type == IRQ_WRITE) 
252                                 ignore_sigio_fd(old_fd->fd);
253                         kfree(old_fd);
254                         continue;
255                 }
256                 prev = &(*prev)->next;
257                 i++;
258         }
259  out:
260         irq_unlock(flags);
261 }
262
263 struct irq_and_dev {
264         int irq;
265         void *dev;
266 };
267
268 static int same_irq_and_dev(struct irq_fd *irq, void *d)
269 {
270         struct irq_and_dev *data = d;
271
272         return((irq->irq == data->irq) && (irq->id == data->dev));
273 }
274
275 void free_irq_by_irq_and_dev(unsigned int irq, void *dev)
276 {
277         struct irq_and_dev data = ((struct irq_and_dev) { .irq  = irq,
278                                                           .dev  = dev });
279
280         free_irq_by_cb(same_irq_and_dev, &data);
281 }
282
283 static int same_fd(struct irq_fd *irq, void *fd)
284 {
285         return(irq->fd == *((int *) fd));
286 }
287
288 void free_irq_by_fd(int fd)
289 {
290         free_irq_by_cb(same_fd, &fd);
291 }
292
293 static struct irq_fd *find_irq_by_fd(int fd, int irqnum, int *index_out)
294 {
295         struct irq_fd *irq;
296         int i = 0;
297
298         for(irq=active_fds; irq != NULL; irq = irq->next){
299                 if((irq->fd == fd) && (irq->irq == irqnum)) break;
300                 i++;
301         }
302         if(irq == NULL){
303                 printk("find_irq_by_fd doesn't have descriptor %d\n", fd);
304                 goto out;
305         }
306         if((pollfds[i].fd != -1) && (pollfds[i].fd != fd)){
307                 printk("find_irq_by_fd - mismatch between active_fds and "
308                        "pollfds, fd %d vs %d, need %d\n", irq->fd, 
309                        pollfds[i].fd, fd);
310                 irq = NULL;
311                 goto out;
312         }
313         *index_out = i;
314  out:
315         return(irq);
316 }
317
318 void free_irq_later(int irq, void *dev_id)
319 {
320         struct irq_fd *irq_fd;
321         unsigned long flags;
322
323         flags = irq_lock();
324         for(irq_fd = active_fds; irq_fd != NULL; irq_fd = irq_fd->next){
325                 if((irq_fd->irq == irq) && (irq_fd->id == dev_id))
326                         break;
327         }
328         if(irq_fd == NULL){
329                 printk("free_irq_later found no irq, irq = %d, "
330                        "dev_id = 0x%p\n", irq, dev_id);
331                 goto out;
332         }
333         irq_fd->freed = 1;
334  out:
335         irq_unlock(flags);
336 }
337
338 void reactivate_fd(int fd, int irqnum)
339 {
340         struct irq_fd *irq;
341         unsigned long flags;
342         int i;
343
344         flags = irq_lock();
345         irq = find_irq_by_fd(fd, irqnum, &i);
346         if(irq == NULL){
347                 irq_unlock(flags);
348                 return;
349         }
350
351         pollfds[i].fd = irq->fd;
352
353         irq_unlock(flags);
354
355         /* This calls activate_fd, so it has to be outside the critical
356          * section.
357          */
358         maybe_sigio_broken(fd, irq->type);
359 }
360
361 void deactivate_fd(int fd, int irqnum)
362 {
363         struct irq_fd *irq;
364         unsigned long flags;
365         int i;
366
367         flags = irq_lock();
368         irq = find_irq_by_fd(fd, irqnum, &i);
369         if(irq == NULL)
370                 goto out;
371         pollfds[i].fd = -1;
372  out:
373         irq_unlock(flags);
374 }
375
376 int deactivate_all_fds(void)
377 {
378         struct irq_fd *irq;
379         int err;
380
381         for(irq=active_fds;irq != NULL;irq = irq->next){
382                 err = os_clear_fd_async(irq->fd);
383                 if(err)
384                         return(err);
385         }
386         /* If there is a signal already queued, after unblocking ignore it */
387         set_handler(SIGIO, SIG_IGN, 0, -1);
388
389         return(0);
390 }
391
392 void forward_ipi(int fd, int pid)
393 {
394         int err;
395
396         err = os_set_owner(fd, pid);
397         if(err < 0)
398                 printk("forward_ipi: set_owner failed, fd = %d, me = %d, "
399                        "target = %d, err = %d\n", fd, os_getpid(), pid, -err);
400 }
401
402 void forward_interrupts(int pid)
403 {
404         struct irq_fd *irq;
405         unsigned long flags;
406         int err;
407
408         flags = irq_lock();
409         for(irq=active_fds;irq != NULL;irq = irq->next){
410                 err = os_set_owner(irq->fd, pid);
411                 if(err < 0){
412                         /* XXX Just remove the irq rather than
413                          * print out an infinite stream of these
414                          */
415                         printk("Failed to forward %d to pid %d, err = %d\n",
416                                irq->fd, pid, -err);
417                 }
418
419                 irq->pid = pid;
420         }
421         irq_unlock(flags);
422 }
423
424 void init_irq_signals(int on_sigstack)
425 {
426         __sighandler_t h;
427         int flags;
428
429         flags = on_sigstack ? SA_ONSTACK : 0;
430         if(timer_irq_inited) h = (__sighandler_t) alarm_handler;
431         else h = boot_timer_handler;
432
433         set_handler(SIGVTALRM, h, flags | SA_RESTART, 
434                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
435         set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
436                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
437         signal(SIGWINCH, SIG_IGN);
438 }
439
440 /*
441  * Overrides for Emacs so that we follow Linus's tabbing style.
442  * Emacs will notice this stuff at the end of the file and automatically
443  * adjust the settings for this buffer only.  This must remain at the end
444  * of the file.
445  * ---------------------------------------------------------------------------
446  * Local variables:
447  * c-file-style: "linux"
448  * End:
449  */