xref: /openbmc/qemu/chardev/wctablet.c (revision 7d87775f) 
1 /*
2  * QEMU Wacom Penpartner serial tablet emulation
3  *
4  * some protocol details:
5  *   http://linuxwacom.sourceforge.net/wiki/index.php/Serial_Protocol_IV
6  *
7  * Copyright (c) 2016 Anatoli Huseu1
8  * Copyright (c) 2016,17 Gerd Hoffmann
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a copy
11  * of this software and associated documentation files (the "Software"), to
12  * deal in the Software without restriction, including without limitation
13  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14  * and/or sell copies of the Software, and to permit persons to whom the
15  * Software is furnished to do so, subject to the following conditions:
16  *
17  * The above copyright notice and this permission notice shall be included in
18  * all copies or substantial portions of the Software.
19  *
20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM
25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26  * THE SOFTWARE.
27  */
28 
29 #include "qemu/osdep.h"
30 #include "qemu/module.h"
31 #include "chardev/char-serial.h"
32 #include "ui/console.h"
33 #include "ui/input.h"
34 #include "trace.h"
35 #include "qom/object.h"
36 
37 
38 #define WC_OUTPUT_BUF_MAX_LEN 512
39 #define WC_COMMAND_MAX_LEN 60
40 
41 #define WC_L7(n) ((n) & 127)
42 #define WC_M7(n) (((n) >> 7) & 127)
43 #define WC_H2(n) ((n) >> 14)
44 
45 #define WC_L4(n) ((n) & 15)
46 #define WC_H4(n) (((n) >> 4) & 15)
47 
48 /* Model string and config string */
49 #define WC_MODEL_STRING_LENGTH 18
50 uint8_t WC_MODEL_STRING[WC_MODEL_STRING_LENGTH + 1] = "~#CT-0045R,V1.3-5,";
51 
52 #define WC_CONFIG_STRING_LENGTH 8
53 uint8_t WC_CONFIG_STRING[WC_CONFIG_STRING_LENGTH + 1] = "96,N,8,0";
54 
55 #define WC_FULL_CONFIG_STRING_LENGTH 61
56 uint8_t WC_FULL_CONFIG_STRING[WC_FULL_CONFIG_STRING_LENGTH + 1] = {
57     0x5c, 0x39, 0x36, 0x2c, 0x4e, 0x2c, 0x38, 0x2c,
58     0x31, 0x28, 0x01, 0x24, 0x57, 0x41, 0x43, 0x30,
59     0x30, 0x34, 0x35, 0x5c, 0x5c, 0x50, 0x45, 0x4e, 0x5c,
60     0x57, 0x41, 0x43, 0x30, 0x30, 0x30, 0x30, 0x5c,
61     0x54, 0x61, 0x62, 0x6c, 0x65, 0x74, 0x0d, 0x0a,
62     0x43, 0x54, 0x2d, 0x30, 0x30, 0x34, 0x35, 0x52,
63     0x2c, 0x56, 0x31, 0x2e, 0x33, 0x2d, 0x35, 0x0d,
64     0x0a, 0x45, 0x37, 0x29
65 };
66 
67 /* This structure is used to save private info for Wacom Tablet. */
68 struct TabletChardev {
69     Chardev parent;
70     QemuInputHandlerState *hs;
71 
72     /* Query string from serial */
73     uint8_t query[100];
74     int query_index;
75 
76     /* Command to be sent to serial port */
77     uint8_t outbuf[WC_OUTPUT_BUF_MAX_LEN];
78     int outlen;
79 
80     int line_speed;
81     bool send_events;
82     int axis[INPUT_AXIS__MAX];
83     bool btns[INPUT_BUTTON__MAX];
84 
85 };
86 typedef struct TabletChardev TabletChardev;
87 
88 #define TYPE_CHARDEV_WCTABLET "chardev-wctablet"
89 DECLARE_INSTANCE_CHECKER(TabletChardev, WCTABLET_CHARDEV,
90                          TYPE_CHARDEV_WCTABLET)
91 
92 
93 static void wctablet_chr_accept_input(Chardev *chr);
94 
95 static void wctablet_shift_input(TabletChardev *tablet, int count)
96 {
97     tablet->query_index -= count;
98     memmove(tablet->query, tablet->query + count, tablet->query_index);
99     tablet->query[tablet->query_index] = 0;
100 }
101 
102 static void wctablet_queue_output(TabletChardev *tablet, uint8_t *buf, int count)
103 {
104     if (tablet->outlen + count > sizeof(tablet->outbuf)) {
105         return;
106     }
107 
108     memcpy(tablet->outbuf + tablet->outlen, buf, count);
109     tablet->outlen += count;
110     wctablet_chr_accept_input(CHARDEV(tablet));
111 }
112 
113 static void wctablet_reset(TabletChardev *tablet)
114 {
115     /* clear buffers */
116     tablet->query_index = 0;
117     tablet->outlen = 0;
118     /* reset state */
119     tablet->send_events = false;
120 }
121 
122 static void wctablet_queue_event(TabletChardev *tablet)
123 {
124     uint8_t codes[8] = { 0xe0, 0, 0, 0, 0, 0, 0 };
125 
126     if (tablet->line_speed != 9600) {
127         return;
128     }
129 
130     int newX = tablet->axis[INPUT_AXIS_X] * 0.1537;
131     int nexY = tablet->axis[INPUT_AXIS_Y] * 0.1152;
132 
133     codes[0] = codes[0] | WC_H2(newX);
134     codes[1] = codes[1] | WC_M7(newX);
135     codes[2] = codes[2] | WC_L7(newX);
136 
137     codes[3] = codes[3] | WC_H2(nexY);
138     codes[4] = codes[4] | WC_M7(nexY);
139     codes[5] = codes[5] | WC_L7(nexY);
140 
141     if (tablet->btns[INPUT_BUTTON_LEFT]) {
142         codes[0] = 0xa0;
143     }
144 
145     wctablet_queue_output(tablet, codes, 7);
146 }
147 
148 static void wctablet_input_event(DeviceState *dev, QemuConsole *src,
149                                 InputEvent *evt)
150 {
151     TabletChardev *tablet = (TabletChardev *)dev;
152     InputMoveEvent *move;
153     InputBtnEvent *btn;
154 
155     switch (evt->type) {
156     case INPUT_EVENT_KIND_ABS:
157         move = evt->u.abs.data;
158         tablet->axis[move->axis] = move->value;
159         break;
160 
161     case INPUT_EVENT_KIND_BTN:
162         btn = evt->u.btn.data;
163         tablet->btns[btn->button] = btn->down;
164         break;
165 
166     default:
167         /* keep gcc happy */
168         break;
169     }
170 }
171 
172 static void wctablet_input_sync(DeviceState *dev)
173 {
174     TabletChardev *tablet = (TabletChardev *)dev;
175 
176     if (tablet->send_events) {
177         wctablet_queue_event(tablet);
178     }
179 }
180 
181 static const QemuInputHandler wctablet_handler = {
182     .name  = "QEMU Wacom Pen Tablet",
183     .mask  = INPUT_EVENT_MASK_BTN | INPUT_EVENT_MASK_ABS,
184     .event = wctablet_input_event,
185     .sync  = wctablet_input_sync,
186 };
187 
188 static void wctablet_chr_accept_input(Chardev *chr)
189 {
190     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
191     int len, canWrite;
192 
193     canWrite = qemu_chr_be_can_write(chr);
194     len = canWrite;
195     if (len > tablet->outlen) {
196         len = tablet->outlen;
197     }
198 
199     if (len) {
200         qemu_chr_be_write(chr, tablet->outbuf, len);
201         tablet->outlen -= len;
202         if (tablet->outlen) {
203             memmove(tablet->outbuf, tablet->outbuf + len, tablet->outlen);
204         }
205     }
206 }
207 
208 static int wctablet_chr_write(struct Chardev *chr,
209                               const uint8_t *buf, int len)
210 {
211     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
212     unsigned int i, clen;
213     char *pos;
214 
215     if (tablet->line_speed != 9600) {
216         return len;
217     }
218     for (i = 0; i < len && tablet->query_index < sizeof(tablet->query) - 1; i++) {
219         tablet->query[tablet->query_index++] = buf[i];
220     }
221     tablet->query[tablet->query_index] = 0;
222 
223     while (tablet->query_index > 0 && (tablet->query[0] == '@'  ||
224                                        tablet->query[0] == '\r' ||
225                                        tablet->query[0] == '\n')) {
226         wctablet_shift_input(tablet, 1);
227     }
228     if (!tablet->query_index) {
229         return len;
230     }
231 
232     if (strncmp((char *)tablet->query, "~#", 2) == 0) {
233         /* init / detect sequence */
234         trace_wct_init();
235         wctablet_shift_input(tablet, 2);
236         wctablet_queue_output(tablet, WC_MODEL_STRING,
237                               WC_MODEL_STRING_LENGTH);
238         return len;
239     }
240 
241     /* detect line */
242     pos = strchr((char *)tablet->query, '\r');
243     if (!pos) {
244         pos = strchr((char *)tablet->query, '\n');
245     }
246     if (!pos) {
247         return len;
248     }
249     clen = pos - (char *)tablet->query;
250 
251     /* process commands */
252     if (strncmp((char *)tablet->query, "RE", 2) == 0 &&
253         clen == 2) {
254         trace_wct_cmd_re();
255         wctablet_shift_input(tablet, 3);
256         wctablet_queue_output(tablet, WC_CONFIG_STRING,
257                               WC_CONFIG_STRING_LENGTH);
258 
259     } else if (strncmp((char *)tablet->query, "ST", 2) == 0 &&
260                clen == 2) {
261         trace_wct_cmd_st();
262         wctablet_shift_input(tablet, 3);
263         tablet->send_events = true;
264         wctablet_queue_event(tablet);
265 
266     } else if (strncmp((char *)tablet->query, "SP", 2) == 0 &&
267                clen == 2) {
268         trace_wct_cmd_sp();
269         wctablet_shift_input(tablet, 3);
270         tablet->send_events = false;
271 
272     } else if (strncmp((char *)tablet->query, "TS", 2) == 0 &&
273                clen == 3) {
274         unsigned int input = tablet->query[2];
275         uint8_t codes[7] = {
276             0xa3,
277             ((input & 0x80) == 0) ? 0x7e : 0x7f,
278             (((WC_H4(input) & 0x7) ^ 0x5) << 4) | (WC_L4(input) ^ 0x7),
279             0x03,
280             0x7f,
281             0x7f,
282             0x00,
283         };
284         trace_wct_cmd_ts(input);
285         wctablet_shift_input(tablet, 4);
286         wctablet_queue_output(tablet, codes, 7);
287 
288     } else {
289         tablet->query[clen] = 0; /* terminate line for printing */
290         trace_wct_cmd_other((char *)tablet->query);
291         wctablet_shift_input(tablet, clen + 1);
292 
293     }
294 
295     return len;
296 }
297 
298 static int wctablet_chr_ioctl(Chardev *chr, int cmd, void *arg)
299 {
300     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
301     QEMUSerialSetParams *ssp;
302 
303     switch (cmd) {
304     case CHR_IOCTL_SERIAL_SET_PARAMS:
305         ssp = arg;
306         if (tablet->line_speed != ssp->speed) {
307             trace_wct_speed(ssp->speed);
308             wctablet_reset(tablet);
309             tablet->line_speed = ssp->speed;
310         }
311         break;
312     default:
313         return -ENOTSUP;
314     }
315     return 0;
316 }
317 
318 static void wctablet_chr_finalize(Object *obj)
319 {
320     TabletChardev *tablet = WCTABLET_CHARDEV(obj);
321 
322     if (tablet->hs) {
323         qemu_input_handler_unregister(tablet->hs);
324     }
325 }
326 
327 static void wctablet_chr_open(Chardev *chr,
328                               ChardevBackend *backend,
329                               bool *be_opened,
330                               Error **errp)
331 {
332     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
333 
334     *be_opened = true;
335 
336     /* init state machine */
337     memcpy(tablet->outbuf, WC_FULL_CONFIG_STRING, WC_FULL_CONFIG_STRING_LENGTH);
338     tablet->outlen = WC_FULL_CONFIG_STRING_LENGTH;
339     tablet->query_index = 0;
340 
341     tablet->hs = qemu_input_handler_register((DeviceState *)tablet,
342                                              &wctablet_handler);
343 }
344 
345 static void wctablet_chr_class_init(ObjectClass *oc, void *data)
346 {
347     ChardevClass *cc = CHARDEV_CLASS(oc);
348 
349     cc->open = wctablet_chr_open;
350     cc->chr_write = wctablet_chr_write;
351     cc->chr_ioctl = wctablet_chr_ioctl;
352     cc->chr_accept_input = wctablet_chr_accept_input;
353 }
354 
355 static const TypeInfo wctablet_type_info = {
356     .name = TYPE_CHARDEV_WCTABLET,
357     .parent = TYPE_CHARDEV,
358     .instance_size = sizeof(TabletChardev),
359     .instance_finalize = wctablet_chr_finalize,
360     .class_init = wctablet_chr_class_init,
361 };
362 
363 static void register_types(void)
364 {
365      type_register_static(&wctablet_type_info);
366 }
367 
368 type_init(register_types);
369