1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * When connected to the machine, the Thrustmaster wheels appear as
4  * a «generic» hid gamepad called "Thrustmaster FFB Wheel".
5  *
6  * When in this mode not every functionality of the wheel, like the force feedback,
7  * are available. To enable all functionalities of a Thrustmaster wheel we have to send
8  * to it a specific USB CONTROL request with a code different for each wheel.
9  *
10  * This driver tries to understand which model of Thrustmaster wheel the generic
11  * "Thrustmaster FFB Wheel" really is and then sends the appropriate control code.
12  *
13  * Copyright (c) 2020-2021 Dario Pagani <dario.pagani.146+linuxk@gmail.com>
14  * Copyright (c) 2020-2021 Kim Kuparinen <kimi.h.kuparinen@gmail.com>
15  */
16 #include <linux/hid.h>
17 #include <linux/usb.h>
18 #include <linux/input.h>
19 #include <linux/slab.h>
20 #include <linux/module.h>
21 
22 /*
23  * These interrupts are used to prevent a nasty crash when initializing the
24  * T300RS. Used in thrustmaster_interrupts().
25  */
26 static const u8 setup_0[] = { 0x42, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
27 static const u8 setup_1[] = { 0x0a, 0x04, 0x90, 0x03, 0x00, 0x00, 0x00, 0x00 };
28 static const u8 setup_2[] = { 0x0a, 0x04, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x00 };
29 static const u8 setup_3[] = { 0x0a, 0x04, 0x12, 0x10, 0x00, 0x00, 0x00, 0x00 };
30 static const u8 setup_4[] = { 0x0a, 0x04, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00 };
31 static const u8 *const setup_arr[] = { setup_0, setup_1, setup_2, setup_3, setup_4 };
32 static const unsigned int setup_arr_sizes[] = {
33 	ARRAY_SIZE(setup_0),
34 	ARRAY_SIZE(setup_1),
35 	ARRAY_SIZE(setup_2),
36 	ARRAY_SIZE(setup_3),
37 	ARRAY_SIZE(setup_4)
38 };
39 /*
40  * This struct contains for each type of
41  * Thrustmaster wheel
42  *
43  * Note: The values are stored in the CPU
44  * endianness, the USB protocols always use
45  * little endian; the macro cpu_to_le[BIT]()
46  * must be used when preparing USB packets
47  * and vice-versa
48  */
49 struct tm_wheel_info {
50 	uint16_t wheel_type;
51 
52 	/*
53 	 * See when the USB control out packet is prepared...
54 	 * @TODO The TMX seems to require multiple control codes to switch.
55 	 */
56 	uint16_t switch_value;
57 
58 	char const *const wheel_name;
59 };
60 
61 /*
62  * Known wheels.
63  * Note: TMX does not work as it requires 2 control packets
64  */
65 static const struct tm_wheel_info tm_wheels_infos[] = {
66 	{0x0306, 0x0006, "Thrustmaster T150RS"},
67 	{0x0206, 0x0005, "Thrustmaster T300RS"},
68 	{0x0204, 0x0005, "Thrustmaster T300 Ferrari Alcantara Edition"},
69 	{0x0002, 0x0002, "Thrustmaster T500RS"}
70 	//{0x0407, 0x0001, "Thrustmaster TMX"}
71 };
72 
73 static const uint8_t tm_wheels_infos_length = 4;
74 
75 /*
76  * This structs contains (in little endian) the response data
77  * of the wheel to the request 73
78  *
79  * A sufficient research to understand what each field does is not
80  * beign conducted yet. The position and meaning of fields are a
81  * just a very optimistic guess based on instinct....
82  */
83 struct __packed tm_wheel_response
84 {
85 	/*
86 	 * Seems to be the type of packet
87 	 * - 0x0049 if is data.a (15 bytes)
88 	 * - 0x0047 if is data.b (7 bytes)
89 	 */
90 	uint16_t type;
91 
92 	union {
93 		struct __packed {
94 			uint16_t field0;
95 			uint16_t field1;
96 			/*
97 			 * Seems to be the model code of the wheel
98 			 * Read table thrustmaster_wheels to values
99 			 */
100 			uint16_t model;
101 
102 			uint16_t field2;
103 			uint16_t field3;
104 			uint16_t field4;
105 			uint16_t field5;
106 		} a;
107 		struct __packed {
108 			uint16_t field0;
109 			uint16_t field1;
110 			uint16_t model;
111 		} b;
112 	} data;
113 };
114 
115 struct tm_wheel {
116 	struct usb_device *usb_dev;
117 	struct urb *urb;
118 
119 	struct usb_ctrlrequest *model_request;
120 	struct tm_wheel_response *response;
121 
122 	struct usb_ctrlrequest *change_request;
123 };
124 
125 /* The control packet to send to wheel */
126 static const struct usb_ctrlrequest model_request = {
127 	.bRequestType = 0xc1,
128 	.bRequest = 73,
129 	.wValue = 0,
130 	.wIndex = 0,
131 	.wLength = cpu_to_le16(0x0010)
132 };
133 
134 static const struct usb_ctrlrequest change_request = {
135 	.bRequestType = 0x41,
136 	.bRequest = 83,
137 	.wValue = 0, // Will be filled by the driver
138 	.wIndex = 0,
139 	.wLength = 0
140 };
141 
142 /*
143  * On some setups initializing the T300RS crashes the kernel,
144  * these interrupts fix that particular issue. So far they haven't caused any
145  * adverse effects in other wheels.
146  */
147 static void thrustmaster_interrupts(struct hid_device *hdev)
148 {
149 	int ret, trans, i, b_ep;
150 	u8 *send_buf = kmalloc(256, GFP_KERNEL);
151 	struct usb_host_endpoint *ep;
152 	struct device *dev = &hdev->dev;
153 	struct usb_interface *usbif = to_usb_interface(dev->parent);
154 	struct usb_device *usbdev = interface_to_usbdev(usbif);
155 
156 	if (!send_buf) {
157 		hid_err(hdev, "failed allocating send buffer\n");
158 		return;
159 	}
160 
161 	ep = &usbif->cur_altsetting->endpoint[1];
162 	b_ep = ep->desc.bEndpointAddress;
163 
164 	for (i = 0; i < ARRAY_SIZE(setup_arr); ++i) {
165 		memcpy(send_buf, setup_arr[i], setup_arr_sizes[i]);
166 
167 		ret = usb_interrupt_msg(usbdev,
168 			usb_sndintpipe(usbdev, b_ep),
169 			send_buf,
170 			setup_arr_sizes[i],
171 			&trans,
172 			USB_CTRL_SET_TIMEOUT);
173 
174 		if (ret) {
175 			hid_err(hdev, "setup data couldn't be sent\n");
176 			return;
177 		}
178 	}
179 
180 	kfree(send_buf);
181 }
182 
183 static void thrustmaster_change_handler(struct urb *urb)
184 {
185 	struct hid_device *hdev = urb->context;
186 
187 	// The wheel seems to kill himself before answering the host and therefore is violating the USB protocol...
188 	if (urb->status == 0 || urb->status == -EPROTO || urb->status == -EPIPE)
189 		hid_info(hdev, "Success?! The wheel should have been initialized!\n");
190 	else
191 		hid_warn(hdev, "URB to change wheel mode seems to have failed with error %d\n", urb->status);
192 }
193 
194 /*
195  * Called by the USB subsystem when the wheel responses to our request
196  * to get [what it seems to be] the wheel's model.
197  *
198  * If the model id is recognized then we send an opportune USB CONTROL REQUEST
199  * to switch the wheel to its full capabilities
200  */
201 static void thrustmaster_model_handler(struct urb *urb)
202 {
203 	struct hid_device *hdev = urb->context;
204 	struct tm_wheel *tm_wheel = hid_get_drvdata(hdev);
205 	uint16_t model = 0;
206 	int i, ret;
207 	const struct tm_wheel_info *twi = 0;
208 
209 	if (urb->status) {
210 		hid_err(hdev, "URB to get model id failed with error %d\n", urb->status);
211 		return;
212 	}
213 
214 	if (tm_wheel->response->type == cpu_to_le16(0x49))
215 		model = le16_to_cpu(tm_wheel->response->data.a.model);
216 	else if (tm_wheel->response->type == cpu_to_le16(0x47))
217 		model = le16_to_cpu(tm_wheel->response->data.b.model);
218 	else {
219 		hid_err(hdev, "Unknown packet type 0x%x, unable to proceed further with wheel init\n", tm_wheel->response->type);
220 		return;
221 	}
222 
223 	for (i = 0; i < tm_wheels_infos_length && !twi; i++)
224 		if (tm_wheels_infos[i].wheel_type == model)
225 			twi = tm_wheels_infos + i;
226 
227 	if (twi)
228 		hid_info(hdev, "Wheel with model id 0x%x is a %s\n", model, twi->wheel_name);
229 	else {
230 		hid_err(hdev, "Unknown wheel's model id 0x%x, unable to proceed further with wheel init\n", model);
231 		return;
232 	}
233 
234 	tm_wheel->change_request->wValue = cpu_to_le16(twi->switch_value);
235 	usb_fill_control_urb(
236 		tm_wheel->urb,
237 		tm_wheel->usb_dev,
238 		usb_sndctrlpipe(tm_wheel->usb_dev, 0),
239 		(char *)tm_wheel->change_request,
240 		0, 0, // We do not expect any response from the wheel
241 		thrustmaster_change_handler,
242 		hdev
243 	);
244 
245 	ret = usb_submit_urb(tm_wheel->urb, GFP_ATOMIC);
246 	if (ret)
247 		hid_err(hdev, "Error %d while submitting the change URB. I am unable to initialize this wheel...\n", ret);
248 }
249 
250 static void thrustmaster_remove(struct hid_device *hdev)
251 {
252 	struct tm_wheel *tm_wheel = hid_get_drvdata(hdev);
253 
254 	usb_kill_urb(tm_wheel->urb);
255 
256 	kfree(tm_wheel->response);
257 	kfree(tm_wheel->model_request);
258 	usb_free_urb(tm_wheel->urb);
259 	kfree(tm_wheel);
260 
261 	hid_hw_stop(hdev);
262 }
263 
264 /*
265  * Function called by HID when a hid Thrustmaster FFB wheel is connected to the host.
266  * This function starts the hid dev, tries to allocate the tm_wheel data structure and
267  * finally send an USB CONTROL REQUEST to the wheel to get [what it seems to be] its
268  * model type.
269  */
270 static int thrustmaster_probe(struct hid_device *hdev, const struct hid_device_id *id)
271 {
272 	int ret = 0;
273 	struct tm_wheel *tm_wheel = 0;
274 
275 	ret = hid_parse(hdev);
276 	if (ret) {
277 		hid_err(hdev, "parse failed with error %d\n", ret);
278 		goto error0;
279 	}
280 
281 	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
282 	if (ret) {
283 		hid_err(hdev, "hw start failed with error %d\n", ret);
284 		goto error0;
285 	}
286 
287 	// Now we allocate the tm_wheel
288 	tm_wheel = kzalloc(sizeof(struct tm_wheel), GFP_KERNEL);
289 	if (!tm_wheel) {
290 		ret = -ENOMEM;
291 		goto error1;
292 	}
293 
294 	tm_wheel->urb = usb_alloc_urb(0, GFP_ATOMIC);
295 	if (!tm_wheel->urb) {
296 		ret = -ENOMEM;
297 		goto error2;
298 	}
299 
300 	tm_wheel->model_request = kmemdup(&model_request,
301 					  sizeof(struct usb_ctrlrequest),
302 					  GFP_KERNEL);
303 	if (!tm_wheel->model_request) {
304 		ret = -ENOMEM;
305 		goto error3;
306 	}
307 
308 	tm_wheel->response = kzalloc(sizeof(struct tm_wheel_response), GFP_KERNEL);
309 	if (!tm_wheel->response) {
310 		ret = -ENOMEM;
311 		goto error4;
312 	}
313 
314 	tm_wheel->change_request = kzalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL);
315 	if (!tm_wheel->model_request) {
316 		ret = -ENOMEM;
317 		goto error5;
318 	}
319 	memcpy(tm_wheel->change_request, &change_request, sizeof(struct usb_ctrlrequest));
320 
321 	tm_wheel->usb_dev = interface_to_usbdev(to_usb_interface(hdev->dev.parent));
322 	hid_set_drvdata(hdev, tm_wheel);
323 
324 	thrustmaster_interrupts(hdev);
325 
326 	usb_fill_control_urb(
327 		tm_wheel->urb,
328 		tm_wheel->usb_dev,
329 		usb_rcvctrlpipe(tm_wheel->usb_dev, 0),
330 		(char *)tm_wheel->model_request,
331 		tm_wheel->response,
332 		sizeof(struct tm_wheel_response),
333 		thrustmaster_model_handler,
334 		hdev
335 	);
336 
337 	ret = usb_submit_urb(tm_wheel->urb, GFP_ATOMIC);
338 	if (ret)
339 		hid_err(hdev, "Error %d while submitting the URB. I am unable to initialize this wheel...\n", ret);
340 
341 	return ret;
342 
343 error5: kfree(tm_wheel->response);
344 error4: kfree(tm_wheel->model_request);
345 error3: usb_free_urb(tm_wheel->urb);
346 error2: kfree(tm_wheel);
347 error1: hid_hw_stop(hdev);
348 error0:
349 	return ret;
350 }
351 
352 static const struct hid_device_id thrustmaster_devices[] = {
353 	{ HID_USB_DEVICE(0x044f, 0xb65d)},
354 	{}
355 };
356 
357 MODULE_DEVICE_TABLE(hid, thrustmaster_devices);
358 
359 static struct hid_driver thrustmaster_driver = {
360 	.name = "hid-thrustmaster",
361 	.id_table = thrustmaster_devices,
362 	.probe = thrustmaster_probe,
363 	.remove = thrustmaster_remove,
364 };
365 
366 module_hid_driver(thrustmaster_driver);
367 
368 MODULE_AUTHOR("Dario Pagani <dario.pagani.146+linuxk@gmail.com>");
369 MODULE_LICENSE("GPL");
370 MODULE_DESCRIPTION("Driver to initialize some steering wheel joysticks from Thrustmaster");
371 
372