Linux 4.1.16
[linux/fpc-iii.git] / drivers / tty / hvc / hvc_xen.c
blob7a3d146a5f0efc0dbc3b94e854adb4d81c85da4d
1 /*
2 * xen console driver interface to hvc_console.c
4 * (c) 2007 Gerd Hoffmann <kraxel@suse.de>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/console.h>
22 #include <linux/delay.h>
23 #include <linux/err.h>
24 #include <linux/irq.h>
25 #include <linux/init.h>
26 #include <linux/types.h>
27 #include <linux/list.h>
29 #include <asm/io.h>
30 #include <asm/xen/hypervisor.h>
32 #include <xen/xen.h>
33 #include <xen/interface/xen.h>
34 #include <xen/hvm.h>
35 #include <xen/grant_table.h>
36 #include <xen/page.h>
37 #include <xen/events.h>
38 #include <xen/interface/io/console.h>
39 #include <xen/interface/sched.h>
40 #include <xen/hvc-console.h>
41 #include <xen/xenbus.h>
43 #include "hvc_console.h"
45 #define HVC_COOKIE 0x58656e /* "Xen" in hex */
47 struct xencons_info {
48 struct list_head list;
49 struct xenbus_device *xbdev;
50 struct xencons_interface *intf;
51 unsigned int evtchn;
52 struct hvc_struct *hvc;
53 int irq;
54 int vtermno;
55 grant_ref_t gntref;
58 static LIST_HEAD(xenconsoles);
59 static DEFINE_SPINLOCK(xencons_lock);
61 /* ------------------------------------------------------------------ */
63 static struct xencons_info *vtermno_to_xencons(int vtermno)
65 struct xencons_info *entry, *n, *ret = NULL;
67 if (list_empty(&xenconsoles))
68 return NULL;
70 list_for_each_entry_safe(entry, n, &xenconsoles, list) {
71 if (entry->vtermno == vtermno) {
72 ret = entry;
73 break;
77 return ret;
80 static inline int xenbus_devid_to_vtermno(int devid)
82 return devid + HVC_COOKIE;
85 static inline void notify_daemon(struct xencons_info *cons)
87 /* Use evtchn: this is called early, before irq is set up. */
88 notify_remote_via_evtchn(cons->evtchn);
91 static int __write_console(struct xencons_info *xencons,
92 const char *data, int len)
94 XENCONS_RING_IDX cons, prod;
95 struct xencons_interface *intf = xencons->intf;
96 int sent = 0;
98 cons = intf->out_cons;
99 prod = intf->out_prod;
100 mb(); /* update queue values before going on */
101 BUG_ON((prod - cons) > sizeof(intf->out));
103 while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
104 intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
106 wmb(); /* write ring before updating pointer */
107 intf->out_prod = prod;
109 if (sent)
110 notify_daemon(xencons);
111 return sent;
114 static int domU_write_console(uint32_t vtermno, const char *data, int len)
116 int ret = len;
117 struct xencons_info *cons = vtermno_to_xencons(vtermno);
118 if (cons == NULL)
119 return -EINVAL;
122 * Make sure the whole buffer is emitted, polling if
123 * necessary. We don't ever want to rely on the hvc daemon
124 * because the most interesting console output is when the
125 * kernel is crippled.
127 while (len) {
128 int sent = __write_console(cons, data, len);
130 data += sent;
131 len -= sent;
133 if (unlikely(len))
134 HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
137 return ret;
140 static int domU_read_console(uint32_t vtermno, char *buf, int len)
142 struct xencons_interface *intf;
143 XENCONS_RING_IDX cons, prod;
144 int recv = 0;
145 struct xencons_info *xencons = vtermno_to_xencons(vtermno);
146 if (xencons == NULL)
147 return -EINVAL;
148 intf = xencons->intf;
150 cons = intf->in_cons;
151 prod = intf->in_prod;
152 mb(); /* get pointers before reading ring */
153 BUG_ON((prod - cons) > sizeof(intf->in));
155 while (cons != prod && recv < len)
156 buf[recv++] = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
158 mb(); /* read ring before consuming */
159 intf->in_cons = cons;
161 notify_daemon(xencons);
162 return recv;
165 static struct hv_ops domU_hvc_ops = {
166 .get_chars = domU_read_console,
167 .put_chars = domU_write_console,
168 .notifier_add = notifier_add_irq,
169 .notifier_del = notifier_del_irq,
170 .notifier_hangup = notifier_hangup_irq,
173 static int dom0_read_console(uint32_t vtermno, char *buf, int len)
175 return HYPERVISOR_console_io(CONSOLEIO_read, len, buf);
179 * Either for a dom0 to write to the system console, or a domU with a
180 * debug version of Xen
182 static int dom0_write_console(uint32_t vtermno, const char *str, int len)
184 int rc = HYPERVISOR_console_io(CONSOLEIO_write, len, (char *)str);
185 if (rc < 0)
186 return rc;
188 return len;
191 static struct hv_ops dom0_hvc_ops = {
192 .get_chars = dom0_read_console,
193 .put_chars = dom0_write_console,
194 .notifier_add = notifier_add_irq,
195 .notifier_del = notifier_del_irq,
196 .notifier_hangup = notifier_hangup_irq,
199 static int xen_hvm_console_init(void)
201 int r;
202 uint64_t v = 0;
203 unsigned long mfn;
204 struct xencons_info *info;
206 if (!xen_hvm_domain())
207 return -ENODEV;
209 info = vtermno_to_xencons(HVC_COOKIE);
210 if (!info) {
211 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
212 if (!info)
213 return -ENOMEM;
214 } else if (info->intf != NULL) {
215 /* already configured */
216 return 0;
219 * If the toolstack (or the hypervisor) hasn't set these values, the
220 * default value is 0. Even though mfn = 0 and evtchn = 0 are
221 * theoretically correct values, in practice they never are and they
222 * mean that a legacy toolstack hasn't initialized the pv console correctly.
224 r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
225 if (r < 0 || v == 0)
226 goto err;
227 info->evtchn = v;
228 v = 0;
229 r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
230 if (r < 0 || v == 0)
231 goto err;
232 mfn = v;
233 info->intf = xen_remap(mfn << PAGE_SHIFT, PAGE_SIZE);
234 if (info->intf == NULL)
235 goto err;
236 info->vtermno = HVC_COOKIE;
238 spin_lock(&xencons_lock);
239 list_add_tail(&info->list, &xenconsoles);
240 spin_unlock(&xencons_lock);
242 return 0;
243 err:
244 kfree(info);
245 return -ENODEV;
248 static int xen_pv_console_init(void)
250 struct xencons_info *info;
252 if (!xen_pv_domain())
253 return -ENODEV;
255 if (!xen_start_info->console.domU.evtchn)
256 return -ENODEV;
258 info = vtermno_to_xencons(HVC_COOKIE);
259 if (!info) {
260 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
261 if (!info)
262 return -ENOMEM;
263 } else if (info->intf != NULL) {
264 /* already configured */
265 return 0;
267 info->evtchn = xen_start_info->console.domU.evtchn;
268 info->intf = mfn_to_virt(xen_start_info->console.domU.mfn);
269 info->vtermno = HVC_COOKIE;
271 spin_lock(&xencons_lock);
272 list_add_tail(&info->list, &xenconsoles);
273 spin_unlock(&xencons_lock);
275 return 0;
278 static int xen_initial_domain_console_init(void)
280 struct xencons_info *info;
282 if (!xen_initial_domain())
283 return -ENODEV;
285 info = vtermno_to_xencons(HVC_COOKIE);
286 if (!info) {
287 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
288 if (!info)
289 return -ENOMEM;
292 info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
293 info->vtermno = HVC_COOKIE;
295 spin_lock(&xencons_lock);
296 list_add_tail(&info->list, &xenconsoles);
297 spin_unlock(&xencons_lock);
299 return 0;
302 static void xen_console_update_evtchn(struct xencons_info *info)
304 if (xen_hvm_domain()) {
305 uint64_t v;
306 int err;
308 err = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
309 if (!err && v)
310 info->evtchn = v;
311 } else
312 info->evtchn = xen_start_info->console.domU.evtchn;
315 void xen_console_resume(void)
317 struct xencons_info *info = vtermno_to_xencons(HVC_COOKIE);
318 if (info != NULL && info->irq) {
319 if (!xen_initial_domain())
320 xen_console_update_evtchn(info);
321 rebind_evtchn_irq(info->evtchn, info->irq);
325 static void xencons_disconnect_backend(struct xencons_info *info)
327 if (info->irq > 0)
328 unbind_from_irqhandler(info->irq, NULL);
329 info->irq = 0;
330 if (info->evtchn > 0)
331 xenbus_free_evtchn(info->xbdev, info->evtchn);
332 info->evtchn = 0;
333 if (info->gntref > 0)
334 gnttab_free_grant_references(info->gntref);
335 info->gntref = 0;
336 if (info->hvc != NULL)
337 hvc_remove(info->hvc);
338 info->hvc = NULL;
341 static void xencons_free(struct xencons_info *info)
343 free_page((unsigned long)info->intf);
344 info->intf = NULL;
345 info->vtermno = 0;
346 kfree(info);
349 static int xen_console_remove(struct xencons_info *info)
351 xencons_disconnect_backend(info);
352 spin_lock(&xencons_lock);
353 list_del(&info->list);
354 spin_unlock(&xencons_lock);
355 if (info->xbdev != NULL)
356 xencons_free(info);
357 else {
358 if (xen_hvm_domain())
359 iounmap(info->intf);
360 kfree(info);
362 return 0;
365 #ifdef CONFIG_HVC_XEN_FRONTEND
366 static int xencons_remove(struct xenbus_device *dev)
368 return xen_console_remove(dev_get_drvdata(&dev->dev));
371 static int xencons_connect_backend(struct xenbus_device *dev,
372 struct xencons_info *info)
374 int ret, evtchn, devid, ref, irq;
375 struct xenbus_transaction xbt;
376 grant_ref_t gref_head;
377 unsigned long mfn;
379 ret = xenbus_alloc_evtchn(dev, &evtchn);
380 if (ret)
381 return ret;
382 info->evtchn = evtchn;
383 irq = bind_evtchn_to_irq(evtchn);
384 if (irq < 0)
385 return irq;
386 info->irq = irq;
387 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
388 info->hvc = hvc_alloc(xenbus_devid_to_vtermno(devid),
389 irq, &domU_hvc_ops, 256);
390 if (IS_ERR(info->hvc))
391 return PTR_ERR(info->hvc);
392 if (xen_pv_domain())
393 mfn = virt_to_mfn(info->intf);
394 else
395 mfn = __pa(info->intf) >> PAGE_SHIFT;
396 ret = gnttab_alloc_grant_references(1, &gref_head);
397 if (ret < 0)
398 return ret;
399 info->gntref = gref_head;
400 ref = gnttab_claim_grant_reference(&gref_head);
401 if (ref < 0)
402 return ref;
403 gnttab_grant_foreign_access_ref(ref, info->xbdev->otherend_id,
404 mfn, 0);
406 again:
407 ret = xenbus_transaction_start(&xbt);
408 if (ret) {
409 xenbus_dev_fatal(dev, ret, "starting transaction");
410 return ret;
412 ret = xenbus_printf(xbt, dev->nodename, "ring-ref", "%d", ref);
413 if (ret)
414 goto error_xenbus;
415 ret = xenbus_printf(xbt, dev->nodename, "port", "%u",
416 evtchn);
417 if (ret)
418 goto error_xenbus;
419 ret = xenbus_transaction_end(xbt, 0);
420 if (ret) {
421 if (ret == -EAGAIN)
422 goto again;
423 xenbus_dev_fatal(dev, ret, "completing transaction");
424 return ret;
427 xenbus_switch_state(dev, XenbusStateInitialised);
428 return 0;
430 error_xenbus:
431 xenbus_transaction_end(xbt, 1);
432 xenbus_dev_fatal(dev, ret, "writing xenstore");
433 return ret;
436 static int xencons_probe(struct xenbus_device *dev,
437 const struct xenbus_device_id *id)
439 int ret, devid;
440 struct xencons_info *info;
442 devid = dev->nodename[strlen(dev->nodename) - 1] - '0';
443 if (devid == 0)
444 return -ENODEV;
446 info = kzalloc(sizeof(struct xencons_info), GFP_KERNEL);
447 if (!info)
448 return -ENOMEM;
449 dev_set_drvdata(&dev->dev, info);
450 info->xbdev = dev;
451 info->vtermno = xenbus_devid_to_vtermno(devid);
452 info->intf = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
453 if (!info->intf)
454 goto error_nomem;
456 ret = xencons_connect_backend(dev, info);
457 if (ret < 0)
458 goto error;
459 spin_lock(&xencons_lock);
460 list_add_tail(&info->list, &xenconsoles);
461 spin_unlock(&xencons_lock);
463 return 0;
465 error_nomem:
466 ret = -ENOMEM;
467 xenbus_dev_fatal(dev, ret, "allocating device memory");
468 error:
469 xencons_disconnect_backend(info);
470 xencons_free(info);
471 return ret;
474 static int xencons_resume(struct xenbus_device *dev)
476 struct xencons_info *info = dev_get_drvdata(&dev->dev);
478 xencons_disconnect_backend(info);
479 memset(info->intf, 0, PAGE_SIZE);
480 return xencons_connect_backend(dev, info);
483 static void xencons_backend_changed(struct xenbus_device *dev,
484 enum xenbus_state backend_state)
486 switch (backend_state) {
487 case XenbusStateReconfiguring:
488 case XenbusStateReconfigured:
489 case XenbusStateInitialising:
490 case XenbusStateInitialised:
491 case XenbusStateUnknown:
492 break;
494 case XenbusStateInitWait:
495 break;
497 case XenbusStateConnected:
498 xenbus_switch_state(dev, XenbusStateConnected);
499 break;
501 case XenbusStateClosed:
502 if (dev->state == XenbusStateClosed)
503 break;
504 /* Missed the backend's CLOSING state -- fallthrough */
505 case XenbusStateClosing:
506 xenbus_frontend_closed(dev);
507 break;
511 static const struct xenbus_device_id xencons_ids[] = {
512 { "console" },
513 { "" }
516 static struct xenbus_driver xencons_driver = {
517 .name = "xenconsole",
518 .ids = xencons_ids,
519 .probe = xencons_probe,
520 .remove = xencons_remove,
521 .resume = xencons_resume,
522 .otherend_changed = xencons_backend_changed,
524 #endif /* CONFIG_HVC_XEN_FRONTEND */
526 static int __init xen_hvc_init(void)
528 int r;
529 struct xencons_info *info;
530 const struct hv_ops *ops;
532 if (!xen_domain())
533 return -ENODEV;
535 if (xen_initial_domain()) {
536 ops = &dom0_hvc_ops;
537 r = xen_initial_domain_console_init();
538 if (r < 0)
539 return r;
540 info = vtermno_to_xencons(HVC_COOKIE);
541 } else {
542 ops = &domU_hvc_ops;
543 if (xen_hvm_domain())
544 r = xen_hvm_console_init();
545 else
546 r = xen_pv_console_init();
547 if (r < 0)
548 return r;
550 info = vtermno_to_xencons(HVC_COOKIE);
551 info->irq = bind_evtchn_to_irq(info->evtchn);
553 if (info->irq < 0)
554 info->irq = 0; /* NO_IRQ */
555 else
556 irq_set_noprobe(info->irq);
558 info->hvc = hvc_alloc(HVC_COOKIE, info->irq, ops, 256);
559 if (IS_ERR(info->hvc)) {
560 r = PTR_ERR(info->hvc);
561 spin_lock(&xencons_lock);
562 list_del(&info->list);
563 spin_unlock(&xencons_lock);
564 if (info->irq)
565 unbind_from_irqhandler(info->irq, NULL);
566 kfree(info);
567 return r;
570 r = 0;
571 #ifdef CONFIG_HVC_XEN_FRONTEND
572 r = xenbus_register_frontend(&xencons_driver);
573 #endif
574 return r;
576 device_initcall(xen_hvc_init);
578 static int xen_cons_init(void)
580 const struct hv_ops *ops;
582 if (!xen_domain())
583 return 0;
585 if (xen_initial_domain())
586 ops = &dom0_hvc_ops;
587 else {
588 int r;
589 ops = &domU_hvc_ops;
591 if (xen_hvm_domain())
592 r = xen_hvm_console_init();
593 else
594 r = xen_pv_console_init();
595 if (r < 0)
596 return r;
599 hvc_instantiate(HVC_COOKIE, 0, ops);
600 return 0;
602 console_initcall(xen_cons_init);
604 #ifdef CONFIG_EARLY_PRINTK
605 static void xenboot_write_console(struct console *console, const char *string,
606 unsigned len)
608 unsigned int linelen, off = 0;
609 const char *pos;
611 if (!xen_pv_domain())
612 return;
614 dom0_write_console(0, string, len);
616 if (xen_initial_domain())
617 return;
619 domU_write_console(0, "(early) ", 8);
620 while (off < len && NULL != (pos = strchr(string+off, '\n'))) {
621 linelen = pos-string+off;
622 if (off + linelen > len)
623 break;
624 domU_write_console(0, string+off, linelen);
625 domU_write_console(0, "\r\n", 2);
626 off += linelen + 1;
628 if (off < len)
629 domU_write_console(0, string+off, len-off);
632 struct console xenboot_console = {
633 .name = "xenboot",
634 .write = xenboot_write_console,
635 .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME,
636 .index = -1,
638 #endif /* CONFIG_EARLY_PRINTK */
640 void xen_raw_console_write(const char *str)
642 ssize_t len = strlen(str);
643 int rc = 0;
645 if (xen_domain()) {
646 rc = dom0_write_console(0, str, len);
647 #ifdef CONFIG_X86
648 if (rc == -ENOSYS && xen_hvm_domain())
649 goto outb_print;
651 } else if (xen_cpuid_base()) {
652 int i;
653 outb_print:
654 for (i = 0; i < len; i++)
655 outb(str[i], 0xe9);
656 #endif
660 void xen_raw_printk(const char *fmt, ...)
662 static char buf[512];
663 va_list ap;
665 va_start(ap, fmt);
666 vsnprintf(buf, sizeof(buf), fmt, ap);
667 va_end(ap);
669 xen_raw_console_write(buf);