xref: /openbmc/qemu/chardev/wctablet.c (revision f7160f32) 
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 
36 
37 #define WC_OUTPUT_BUF_MAX_LEN 512
38 #define WC_COMMAND_MAX_LEN 60
39 
40 #define WC_L7(n) ((n) & 127)
41 #define WC_M7(n) (((n) >> 7) & 127)
42 #define WC_H2(n) ((n) >> 14)
43 
44 #define WC_L4(n) ((n) & 15)
45 #define WC_H4(n) (((n) >> 4) & 15)
46 
47 /* Model string and config string */
48 #define WC_MODEL_STRING_LENGTH 18
49 uint8_t WC_MODEL_STRING[WC_MODEL_STRING_LENGTH + 1] = "~#CT-0045R,V1.3-5,";
50 
51 #define WC_CONFIG_STRING_LENGTH 8
52 uint8_t WC_CONFIG_STRING[WC_CONFIG_STRING_LENGTH + 1] = "96,N,8,0";
53 
54 #define WC_FULL_CONFIG_STRING_LENGTH 61
55 uint8_t WC_FULL_CONFIG_STRING[WC_FULL_CONFIG_STRING_LENGTH + 1] = {
56     0x5c, 0x39, 0x36, 0x2c, 0x4e, 0x2c, 0x38, 0x2c,
57     0x31, 0x28, 0x01, 0x24, 0x57, 0x41, 0x43, 0x30,
58     0x30, 0x34, 0x35, 0x5c, 0x5c, 0x50, 0x45, 0x4e, 0x5c,
59     0x57, 0x41, 0x43, 0x30, 0x30, 0x30, 0x30, 0x5c,
60     0x54, 0x61, 0x62, 0x6c, 0x65, 0x74, 0x0d, 0x0a,
61     0x43, 0x54, 0x2d, 0x30, 0x30, 0x34, 0x35, 0x52,
62     0x2c, 0x56, 0x31, 0x2e, 0x33, 0x2d, 0x35, 0x0d,
63     0x0a, 0x45, 0x37, 0x29
64 };
65 
66 /* This structure is used to save private info for Wacom Tablet. */
67 typedef struct {
68     Chardev parent;
69     QemuInputHandlerState *hs;
70 
71     /* Query string from serial */
72     uint8_t query[100];
73     int query_index;
74 
75     /* Command to be sent to serial port */
76     uint8_t outbuf[WC_OUTPUT_BUF_MAX_LEN];
77     int outlen;
78 
79     int line_speed;
80     bool send_events;
81     int axis[INPUT_AXIS__MAX];
82     bool btns[INPUT_BUTTON__MAX];
83 
84 } TabletChardev;
85 
86 #define TYPE_CHARDEV_WCTABLET "chardev-wctablet"
87 #define WCTABLET_CHARDEV(obj)                                      \
88     OBJECT_CHECK(TabletChardev, (obj), TYPE_CHARDEV_WCTABLET)
89 
90 
91 static void wctablet_chr_accept_input(Chardev *chr);
92 
93 static void wctablet_shift_input(TabletChardev *tablet, int count)
94 {
95     tablet->query_index -= count;
96     memmove(tablet->query, tablet->query + count, tablet->query_index);
97     tablet->query[tablet->query_index] = 0;
98 }
99 
100 static void wctablet_queue_output(TabletChardev *tablet, uint8_t *buf, int count)
101 {
102     if (tablet->outlen + count > sizeof(tablet->outbuf)) {
103         return;
104     }
105 
106     memcpy(tablet->outbuf + tablet->outlen, buf, count);
107     tablet->outlen += count;
108     wctablet_chr_accept_input(CHARDEV(tablet));
109 }
110 
111 static void wctablet_reset(TabletChardev *tablet)
112 {
113     /* clear buffers */
114     tablet->query_index = 0;
115     tablet->outlen = 0;
116     /* reset state */
117     tablet->send_events = false;
118 }
119 
120 static void wctablet_queue_event(TabletChardev *tablet)
121 {
122     uint8_t codes[8] = { 0xe0, 0, 0, 0, 0, 0, 0 };
123 
124     if (tablet->line_speed != 9600) {
125         return;
126     }
127 
128     int newX = tablet->axis[INPUT_AXIS_X] * 0.1537;
129     int nexY = tablet->axis[INPUT_AXIS_Y] * 0.1152;
130 
131     codes[0] = codes[0] | WC_H2(newX);
132     codes[1] = codes[1] | WC_M7(newX);
133     codes[2] = codes[2] | WC_L7(newX);
134 
135     codes[3] = codes[3] | WC_H2(nexY);
136     codes[4] = codes[4] | WC_M7(nexY);
137     codes[5] = codes[5] | WC_L7(nexY);
138 
139     if (tablet->btns[INPUT_BUTTON_LEFT]) {
140         codes[0] = 0xa0;
141     }
142 
143     wctablet_queue_output(tablet, codes, 7);
144 }
145 
146 static void wctablet_input_event(DeviceState *dev, QemuConsole *src,
147                                 InputEvent *evt)
148 {
149     TabletChardev *tablet = (TabletChardev *)dev;
150     InputMoveEvent *move;
151     InputBtnEvent *btn;
152 
153     switch (evt->type) {
154     case INPUT_EVENT_KIND_ABS:
155         move = evt->u.abs.data;
156         tablet->axis[move->axis] = move->value;
157         break;
158 
159     case INPUT_EVENT_KIND_BTN:
160         btn = evt->u.btn.data;
161         tablet->btns[btn->button] = btn->down;
162         break;
163 
164     default:
165         /* keep gcc happy */
166         break;
167     }
168 }
169 
170 static void wctablet_input_sync(DeviceState *dev)
171 {
172     TabletChardev *tablet = (TabletChardev *)dev;
173 
174     if (tablet->send_events) {
175         wctablet_queue_event(tablet);
176     }
177 }
178 
179 static QemuInputHandler wctablet_handler = {
180     .name  = "QEMU Wacom Pen Tablet",
181     .mask  = INPUT_EVENT_MASK_BTN | INPUT_EVENT_MASK_ABS,
182     .event = wctablet_input_event,
183     .sync  = wctablet_input_sync,
184 };
185 
186 static void wctablet_chr_accept_input(Chardev *chr)
187 {
188     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
189     int len, canWrite;
190 
191     canWrite = qemu_chr_be_can_write(chr);
192     len = canWrite;
193     if (len > tablet->outlen) {
194         len = tablet->outlen;
195     }
196 
197     if (len) {
198         qemu_chr_be_write(chr, tablet->outbuf, len);
199         tablet->outlen -= len;
200         if (tablet->outlen) {
201             memmove(tablet->outbuf, tablet->outbuf + len, tablet->outlen);
202         }
203     }
204 }
205 
206 static int wctablet_chr_write(struct Chardev *chr,
207                               const uint8_t *buf, int len)
208 {
209     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
210     unsigned int i, clen;
211     char *pos;
212 
213     if (tablet->line_speed != 9600) {
214         return len;
215     }
216     for (i = 0; i < len && tablet->query_index < sizeof(tablet->query) - 1; i++) {
217         tablet->query[tablet->query_index++] = buf[i];
218     }
219     tablet->query[tablet->query_index] = 0;
220 
221     while (tablet->query_index > 0 && (tablet->query[0] == '@'  ||
222                                        tablet->query[0] == '\r' ||
223                                        tablet->query[0] == '\n')) {
224         wctablet_shift_input(tablet, 1);
225     }
226     if (!tablet->query_index) {
227         return len;
228     }
229 
230     if (strncmp((char *)tablet->query, "~#", 2) == 0) {
231         /* init / detect sequence */
232         trace_wct_init();
233         wctablet_shift_input(tablet, 2);
234         wctablet_queue_output(tablet, WC_MODEL_STRING,
235                               WC_MODEL_STRING_LENGTH);
236         return len;
237     }
238 
239     /* detect line */
240     pos = strchr((char *)tablet->query, '\r');
241     if (!pos) {
242         pos = strchr((char *)tablet->query, '\n');
243     }
244     if (!pos) {
245         return len;
246     }
247     clen = pos - (char *)tablet->query;
248 
249     /* process commands */
250     if (strncmp((char *)tablet->query, "RE", 2) == 0 &&
251         clen == 2) {
252         trace_wct_cmd_re();
253         wctablet_shift_input(tablet, 3);
254         wctablet_queue_output(tablet, WC_CONFIG_STRING,
255                               WC_CONFIG_STRING_LENGTH);
256 
257     } else if (strncmp((char *)tablet->query, "ST", 2) == 0 &&
258                clen == 2) {
259         trace_wct_cmd_st();
260         wctablet_shift_input(tablet, 3);
261         tablet->send_events = true;
262         wctablet_queue_event(tablet);
263 
264     } else if (strncmp((char *)tablet->query, "SP", 2) == 0 &&
265                clen == 2) {
266         trace_wct_cmd_sp();
267         wctablet_shift_input(tablet, 3);
268         tablet->send_events = false;
269 
270     } else if (strncmp((char *)tablet->query, "TS", 2) == 0 &&
271                clen == 3) {
272         unsigned int input = tablet->query[2];
273         uint8_t codes[7] = {
274             0xa3,
275             ((input & 0x80) == 0) ? 0x7e : 0x7f,
276             (((WC_H4(input) & 0x7) ^ 0x5) << 4) | (WC_L4(input) ^ 0x7),
277             0x03,
278             0x7f,
279             0x7f,
280             0x00,
281         };
282         trace_wct_cmd_ts(input);
283         wctablet_shift_input(tablet, 4);
284         wctablet_queue_output(tablet, codes, 7);
285 
286     } else {
287         tablet->query[clen] = 0; /* terminate line for printing */
288         trace_wct_cmd_other((char *)tablet->query);
289         wctablet_shift_input(tablet, clen + 1);
290 
291     }
292 
293     return len;
294 }
295 
296 static int wctablet_chr_ioctl(Chardev *chr, int cmd, void *arg)
297 {
298     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
299     QEMUSerialSetParams *ssp;
300 
301     switch (cmd) {
302     case CHR_IOCTL_SERIAL_SET_PARAMS:
303         ssp = arg;
304         if (tablet->line_speed != ssp->speed) {
305             trace_wct_speed(ssp->speed);
306             wctablet_reset(tablet);
307             tablet->line_speed = ssp->speed;
308         }
309         break;
310     default:
311         return -ENOTSUP;
312     }
313     return 0;
314 }
315 
316 static void wctablet_chr_finalize(Object *obj)
317 {
318     TabletChardev *tablet = WCTABLET_CHARDEV(obj);
319 
320     qemu_input_handler_unregister(tablet->hs);
321     g_free(tablet);
322 }
323 
324 static void wctablet_chr_open(Chardev *chr,
325                               ChardevBackend *backend,
326                               bool *be_opened,
327                               Error **errp)
328 {
329     TabletChardev *tablet = WCTABLET_CHARDEV(chr);
330 
331     *be_opened = true;
332 
333     /* init state machine */
334     memcpy(tablet->outbuf, WC_FULL_CONFIG_STRING, WC_FULL_CONFIG_STRING_LENGTH);
335     tablet->outlen = WC_FULL_CONFIG_STRING_LENGTH;
336     tablet->query_index = 0;
337 
338     tablet->hs = qemu_input_handler_register((DeviceState *)tablet,
339                                              &wctablet_handler);
340 }
341 
342 static void wctablet_chr_class_init(ObjectClass *oc, void *data)
343 {
344     ChardevClass *cc = CHARDEV_CLASS(oc);
345 
346     cc->open = wctablet_chr_open;
347     cc->chr_write = wctablet_chr_write;
348     cc->chr_ioctl = wctablet_chr_ioctl;
349     cc->chr_accept_input = wctablet_chr_accept_input;
350 }
351 
352 static const TypeInfo wctablet_type_info = {
353     .name = TYPE_CHARDEV_WCTABLET,
354     .parent = TYPE_CHARDEV,
355     .instance_size = sizeof(TabletChardev),
356     .instance_finalize = wctablet_chr_finalize,
357     .class_init = wctablet_chr_class_init,
358 };
359 
360 static void register_types(void)
361 {
362      type_register_static(&wctablet_type_info);
363 }
364 
365 type_init(register_types);
366