1 /*
2  * Xen para-virtual input device
3  *
4  * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
5  * Copyright (C) 2006-2008 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
6  *
7  *  Based on linux/drivers/input/mouse/sermouse.c
8  *
9  *  This file is subject to the terms and conditions of the GNU General Public
10  *  License. See the file COPYING in the main directory of this archive for
11  *  more details.
12  */
13 
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/module.h>
19 #include <linux/input.h>
20 #include <linux/slab.h>
21 
22 #include <asm/xen/hypervisor.h>
23 
24 #include <xen/xen.h>
25 #include <xen/events.h>
26 #include <xen/page.h>
27 #include <xen/grant_table.h>
28 #include <xen/interface/grant_table.h>
29 #include <xen/interface/io/fbif.h>
30 #include <xen/interface/io/kbdif.h>
31 #include <xen/xenbus.h>
32 #include <xen/platform_pci.h>
33 
34 struct xenkbd_info {
35 	struct input_dev *kbd;
36 	struct input_dev *ptr;
37 	struct xenkbd_page *page;
38 	int gref;
39 	int irq;
40 	struct xenbus_device *xbdev;
41 	char phys[32];
42 };
43 
44 static int xenkbd_remove(struct xenbus_device *);
45 static int xenkbd_connect_backend(struct xenbus_device *, struct xenkbd_info *);
46 static void xenkbd_disconnect_backend(struct xenkbd_info *);
47 
48 /*
49  * Note: if you need to send out events, see xenfb_do_update() for how
50  * to do that.
51  */
52 
53 static irqreturn_t input_handler(int rq, void *dev_id)
54 {
55 	struct xenkbd_info *info = dev_id;
56 	struct xenkbd_page *page = info->page;
57 	__u32 cons, prod;
58 
59 	prod = page->in_prod;
60 	if (prod == page->in_cons)
61 		return IRQ_HANDLED;
62 	rmb();			/* ensure we see ring contents up to prod */
63 	for (cons = page->in_cons; cons != prod; cons++) {
64 		union xenkbd_in_event *event;
65 		struct input_dev *dev;
66 		event = &XENKBD_IN_RING_REF(page, cons);
67 
68 		dev = info->ptr;
69 		switch (event->type) {
70 		case XENKBD_TYPE_MOTION:
71 			input_report_rel(dev, REL_X, event->motion.rel_x);
72 			input_report_rel(dev, REL_Y, event->motion.rel_y);
73 			if (event->motion.rel_z)
74 				input_report_rel(dev, REL_WHEEL,
75 						 -event->motion.rel_z);
76 			break;
77 		case XENKBD_TYPE_KEY:
78 			dev = NULL;
79 			if (test_bit(event->key.keycode, info->kbd->keybit))
80 				dev = info->kbd;
81 			if (test_bit(event->key.keycode, info->ptr->keybit))
82 				dev = info->ptr;
83 			if (dev)
84 				input_report_key(dev, event->key.keycode,
85 						 event->key.pressed);
86 			else
87 				pr_warning("unhandled keycode 0x%x\n",
88 					   event->key.keycode);
89 			break;
90 		case XENKBD_TYPE_POS:
91 			input_report_abs(dev, ABS_X, event->pos.abs_x);
92 			input_report_abs(dev, ABS_Y, event->pos.abs_y);
93 			if (event->pos.rel_z)
94 				input_report_rel(dev, REL_WHEEL,
95 						 -event->pos.rel_z);
96 			break;
97 		}
98 		if (dev)
99 			input_sync(dev);
100 	}
101 	mb();			/* ensure we got ring contents */
102 	page->in_cons = cons;
103 	notify_remote_via_irq(info->irq);
104 
105 	return IRQ_HANDLED;
106 }
107 
108 static int xenkbd_probe(struct xenbus_device *dev,
109 				  const struct xenbus_device_id *id)
110 {
111 	int ret, i, abs;
112 	struct xenkbd_info *info;
113 	struct input_dev *kbd, *ptr;
114 
115 	info = kzalloc(sizeof(*info), GFP_KERNEL);
116 	if (!info) {
117 		xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
118 		return -ENOMEM;
119 	}
120 	dev_set_drvdata(&dev->dev, info);
121 	info->xbdev = dev;
122 	info->irq = -1;
123 	info->gref = -1;
124 	snprintf(info->phys, sizeof(info->phys), "xenbus/%s", dev->nodename);
125 
126 	info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
127 	if (!info->page)
128 		goto error_nomem;
129 
130 	if (xenbus_scanf(XBT_NIL, dev->otherend, "feature-abs-pointer", "%d", &abs) < 0)
131 		abs = 0;
132 	if (abs)
133 		xenbus_printf(XBT_NIL, dev->nodename, "request-abs-pointer", "1");
134 
135 	/* keyboard */
136 	kbd = input_allocate_device();
137 	if (!kbd)
138 		goto error_nomem;
139 	kbd->name = "Xen Virtual Keyboard";
140 	kbd->phys = info->phys;
141 	kbd->id.bustype = BUS_PCI;
142 	kbd->id.vendor = 0x5853;
143 	kbd->id.product = 0xffff;
144 
145 	__set_bit(EV_KEY, kbd->evbit);
146 	for (i = KEY_ESC; i < KEY_UNKNOWN; i++)
147 		__set_bit(i, kbd->keybit);
148 	for (i = KEY_OK; i < KEY_MAX; i++)
149 		__set_bit(i, kbd->keybit);
150 
151 	ret = input_register_device(kbd);
152 	if (ret) {
153 		input_free_device(kbd);
154 		xenbus_dev_fatal(dev, ret, "input_register_device(kbd)");
155 		goto error;
156 	}
157 	info->kbd = kbd;
158 
159 	/* pointing device */
160 	ptr = input_allocate_device();
161 	if (!ptr)
162 		goto error_nomem;
163 	ptr->name = "Xen Virtual Pointer";
164 	ptr->phys = info->phys;
165 	ptr->id.bustype = BUS_PCI;
166 	ptr->id.vendor = 0x5853;
167 	ptr->id.product = 0xfffe;
168 
169 	if (abs) {
170 		__set_bit(EV_ABS, ptr->evbit);
171 		input_set_abs_params(ptr, ABS_X, 0, XENFB_WIDTH, 0, 0);
172 		input_set_abs_params(ptr, ABS_Y, 0, XENFB_HEIGHT, 0, 0);
173 	} else {
174 		input_set_capability(ptr, EV_REL, REL_X);
175 		input_set_capability(ptr, EV_REL, REL_Y);
176 	}
177 	input_set_capability(ptr, EV_REL, REL_WHEEL);
178 
179 	__set_bit(EV_KEY, ptr->evbit);
180 	for (i = BTN_LEFT; i <= BTN_TASK; i++)
181 		__set_bit(i, ptr->keybit);
182 
183 	ret = input_register_device(ptr);
184 	if (ret) {
185 		input_free_device(ptr);
186 		xenbus_dev_fatal(dev, ret, "input_register_device(ptr)");
187 		goto error;
188 	}
189 	info->ptr = ptr;
190 
191 	ret = xenkbd_connect_backend(dev, info);
192 	if (ret < 0)
193 		goto error;
194 
195 	return 0;
196 
197  error_nomem:
198 	ret = -ENOMEM;
199 	xenbus_dev_fatal(dev, ret, "allocating device memory");
200  error:
201 	xenkbd_remove(dev);
202 	return ret;
203 }
204 
205 static int xenkbd_resume(struct xenbus_device *dev)
206 {
207 	struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
208 
209 	xenkbd_disconnect_backend(info);
210 	memset(info->page, 0, PAGE_SIZE);
211 	return xenkbd_connect_backend(dev, info);
212 }
213 
214 static int xenkbd_remove(struct xenbus_device *dev)
215 {
216 	struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
217 
218 	xenkbd_disconnect_backend(info);
219 	if (info->kbd)
220 		input_unregister_device(info->kbd);
221 	if (info->ptr)
222 		input_unregister_device(info->ptr);
223 	free_page((unsigned long)info->page);
224 	kfree(info);
225 	return 0;
226 }
227 
228 static int xenkbd_connect_backend(struct xenbus_device *dev,
229 				  struct xenkbd_info *info)
230 {
231 	int ret, evtchn;
232 	struct xenbus_transaction xbt;
233 
234 	ret = gnttab_grant_foreign_access(dev->otherend_id,
235 	                                  virt_to_mfn(info->page), 0);
236 	if (ret < 0)
237 		return ret;
238 	info->gref = ret;
239 
240 	ret = xenbus_alloc_evtchn(dev, &evtchn);
241 	if (ret)
242 		goto error_grant;
243 	ret = bind_evtchn_to_irqhandler(evtchn, input_handler,
244 					0, dev->devicetype, info);
245 	if (ret < 0) {
246 		xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
247 		goto error_evtchan;
248 	}
249 	info->irq = ret;
250 
251  again:
252 	ret = xenbus_transaction_start(&xbt);
253 	if (ret) {
254 		xenbus_dev_fatal(dev, ret, "starting transaction");
255 		goto error_irqh;
256 	}
257 	ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
258 			    virt_to_mfn(info->page));
259 	if (ret)
260 		goto error_xenbus;
261 	ret = xenbus_printf(xbt, dev->nodename, "page-gref", "%u", info->gref);
262 	if (ret)
263 		goto error_xenbus;
264 	ret = xenbus_printf(xbt, dev->nodename, "event-channel", "%u",
265 			    evtchn);
266 	if (ret)
267 		goto error_xenbus;
268 	ret = xenbus_transaction_end(xbt, 0);
269 	if (ret) {
270 		if (ret == -EAGAIN)
271 			goto again;
272 		xenbus_dev_fatal(dev, ret, "completing transaction");
273 		goto error_irqh;
274 	}
275 
276 	xenbus_switch_state(dev, XenbusStateInitialised);
277 	return 0;
278 
279  error_xenbus:
280 	xenbus_transaction_end(xbt, 1);
281 	xenbus_dev_fatal(dev, ret, "writing xenstore");
282  error_irqh:
283 	unbind_from_irqhandler(info->irq, info);
284 	info->irq = -1;
285  error_evtchan:
286 	xenbus_free_evtchn(dev, evtchn);
287  error_grant:
288 	gnttab_end_foreign_access(info->gref, 0, 0UL);
289 	info->gref = -1;
290 	return ret;
291 }
292 
293 static void xenkbd_disconnect_backend(struct xenkbd_info *info)
294 {
295 	if (info->irq >= 0)
296 		unbind_from_irqhandler(info->irq, info);
297 	info->irq = -1;
298 	if (info->gref >= 0)
299 		gnttab_end_foreign_access(info->gref, 0, 0UL);
300 	info->gref = -1;
301 }
302 
303 static void xenkbd_backend_changed(struct xenbus_device *dev,
304 				   enum xenbus_state backend_state)
305 {
306 	struct xenkbd_info *info = dev_get_drvdata(&dev->dev);
307 	int ret, val;
308 
309 	switch (backend_state) {
310 	case XenbusStateInitialising:
311 	case XenbusStateInitialised:
312 	case XenbusStateReconfiguring:
313 	case XenbusStateReconfigured:
314 	case XenbusStateUnknown:
315 		break;
316 
317 	case XenbusStateInitWait:
318 InitWait:
319 		ret = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
320 				   "feature-abs-pointer", "%d", &val);
321 		if (ret < 0)
322 			val = 0;
323 		if (val) {
324 			ret = xenbus_printf(XBT_NIL, info->xbdev->nodename,
325 					    "request-abs-pointer", "1");
326 			if (ret)
327 				pr_warning("xenkbd: can't request abs-pointer");
328 		}
329 
330 		xenbus_switch_state(dev, XenbusStateConnected);
331 		break;
332 
333 	case XenbusStateConnected:
334 		/*
335 		 * Work around xenbus race condition: If backend goes
336 		 * through InitWait to Connected fast enough, we can
337 		 * get Connected twice here.
338 		 */
339 		if (dev->state != XenbusStateConnected)
340 			goto InitWait; /* no InitWait seen yet, fudge it */
341 
342 		/* Set input abs params to match backend screen res */
343 		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
344 				 "width", "%d", &val) > 0)
345 			input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
346 
347 		if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
348 				 "height", "%d", &val) > 0)
349 			input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
350 
351 		break;
352 
353 	case XenbusStateClosed:
354 		if (dev->state == XenbusStateClosed)
355 			break;
356 		/* Missed the backend's CLOSING state -- fallthrough */
357 	case XenbusStateClosing:
358 		xenbus_frontend_closed(dev);
359 		break;
360 	}
361 }
362 
363 static const struct xenbus_device_id xenkbd_ids[] = {
364 	{ "vkbd" },
365 	{ "" }
366 };
367 
368 static struct xenbus_driver xenkbd_driver = {
369 	.ids = xenkbd_ids,
370 	.probe = xenkbd_probe,
371 	.remove = xenkbd_remove,
372 	.resume = xenkbd_resume,
373 	.otherend_changed = xenkbd_backend_changed,
374 };
375 
376 static int __init xenkbd_init(void)
377 {
378 	if (!xen_domain())
379 		return -ENODEV;
380 
381 	/* Nothing to do if running in dom0. */
382 	if (xen_initial_domain())
383 		return -ENODEV;
384 
385 	if (!xen_has_pv_devices())
386 		return -ENODEV;
387 
388 	return xenbus_register_frontend(&xenkbd_driver);
389 }
390 
391 static void __exit xenkbd_cleanup(void)
392 {
393 	xenbus_unregister_driver(&xenkbd_driver);
394 }
395 
396 module_init(xenkbd_init);
397 module_exit(xenkbd_cleanup);
398 
399 MODULE_DESCRIPTION("Xen virtual keyboard/pointer device frontend");
400 MODULE_LICENSE("GPL");
401 MODULE_ALIAS("xen:vkbd");
402