1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Bluetooth HCI serdev driver lib
4  *
5  *  Copyright (C) 2017  Linaro, Ltd., Rob Herring <robh@kernel.org>
6  *
7  *  Based on hci_ldisc.c:
8  *
9  *  Copyright (C) 2000-2001  Qualcomm Incorporated
10  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
11  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/types.h>
16 #include <linux/serdev.h>
17 #include <linux/skbuff.h>
18 
19 #include <net/bluetooth/bluetooth.h>
20 #include <net/bluetooth/hci_core.h>
21 
22 #include "hci_uart.h"
23 
24 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
25 {
26 	struct hci_dev *hdev = hu->hdev;
27 
28 	/* Update HCI stat counters */
29 	switch (pkt_type) {
30 	case HCI_COMMAND_PKT:
31 		hdev->stat.cmd_tx++;
32 		break;
33 
34 	case HCI_ACLDATA_PKT:
35 		hdev->stat.acl_tx++;
36 		break;
37 
38 	case HCI_SCODATA_PKT:
39 		hdev->stat.sco_tx++;
40 		break;
41 	}
42 }
43 
44 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
45 {
46 	struct sk_buff *skb = hu->tx_skb;
47 
48 	if (!skb) {
49 		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
50 			skb = hu->proto->dequeue(hu);
51 	} else
52 		hu->tx_skb = NULL;
53 
54 	return skb;
55 }
56 
57 static void hci_uart_write_work(struct work_struct *work)
58 {
59 	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
60 	struct serdev_device *serdev = hu->serdev;
61 	struct hci_dev *hdev = hu->hdev;
62 	struct sk_buff *skb;
63 
64 	/* REVISIT:
65 	 * should we cope with bad skbs or ->write() returning an error value?
66 	 */
67 	do {
68 		clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
69 
70 		while ((skb = hci_uart_dequeue(hu))) {
71 			int len;
72 
73 			len = serdev_device_write_buf(serdev,
74 						      skb->data, skb->len);
75 			hdev->stat.byte_tx += len;
76 
77 			skb_pull(skb, len);
78 			if (skb->len) {
79 				hu->tx_skb = skb;
80 				break;
81 			}
82 
83 			hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
84 			kfree_skb(skb);
85 		}
86 	} while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
87 
88 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
89 }
90 
91 /* ------- Interface to HCI layer ------ */
92 
93 /* Reset device */
94 static int hci_uart_flush(struct hci_dev *hdev)
95 {
96 	struct hci_uart *hu  = hci_get_drvdata(hdev);
97 
98 	BT_DBG("hdev %p serdev %p", hdev, hu->serdev);
99 
100 	if (hu->tx_skb) {
101 		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
102 	}
103 
104 	/* Flush any pending characters in the driver and discipline. */
105 	serdev_device_write_flush(hu->serdev);
106 
107 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
108 		hu->proto->flush(hu);
109 
110 	return 0;
111 }
112 
113 /* Initialize device */
114 static int hci_uart_open(struct hci_dev *hdev)
115 {
116 	BT_DBG("%s %p", hdev->name, hdev);
117 
118 	/* Undo clearing this from hci_uart_close() */
119 	hdev->flush = hci_uart_flush;
120 
121 	return 0;
122 }
123 
124 /* Close device */
125 static int hci_uart_close(struct hci_dev *hdev)
126 {
127 	BT_DBG("hdev %p", hdev);
128 
129 	hci_uart_flush(hdev);
130 	hdev->flush = NULL;
131 
132 	return 0;
133 }
134 
135 /* Send frames from HCI layer */
136 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
137 {
138 	struct hci_uart *hu = hci_get_drvdata(hdev);
139 
140 	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
141 	       skb->len);
142 
143 	hu->proto->enqueue(hu, skb);
144 
145 	hci_uart_tx_wakeup(hu);
146 
147 	return 0;
148 }
149 
150 static int hci_uart_setup(struct hci_dev *hdev)
151 {
152 	struct hci_uart *hu = hci_get_drvdata(hdev);
153 	struct hci_rp_read_local_version *ver;
154 	struct sk_buff *skb;
155 	unsigned int speed;
156 	int err;
157 
158 	/* Init speed if any */
159 	if (hu->init_speed)
160 		speed = hu->init_speed;
161 	else if (hu->proto->init_speed)
162 		speed = hu->proto->init_speed;
163 	else
164 		speed = 0;
165 
166 	if (speed)
167 		serdev_device_set_baudrate(hu->serdev, speed);
168 
169 	/* Operational speed if any */
170 	if (hu->oper_speed)
171 		speed = hu->oper_speed;
172 	else if (hu->proto->oper_speed)
173 		speed = hu->proto->oper_speed;
174 	else
175 		speed = 0;
176 
177 	if (hu->proto->set_baudrate && speed) {
178 		err = hu->proto->set_baudrate(hu, speed);
179 		if (err)
180 			bt_dev_err(hdev, "Failed to set baudrate");
181 		else
182 			serdev_device_set_baudrate(hu->serdev, speed);
183 	}
184 
185 	if (hu->proto->setup)
186 		return hu->proto->setup(hu);
187 
188 	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
189 		return 0;
190 
191 	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
192 			     HCI_INIT_TIMEOUT);
193 	if (IS_ERR(skb)) {
194 		bt_dev_err(hdev, "Reading local version info failed (%ld)",
195 			   PTR_ERR(skb));
196 		return 0;
197 	}
198 
199 	if (skb->len != sizeof(*ver))
200 		bt_dev_err(hdev, "Event length mismatch for version info");
201 
202 	kfree_skb(skb);
203 	return 0;
204 }
205 
206 /** hci_uart_write_wakeup - transmit buffer wakeup
207  * @serdev: serial device
208  *
209  * This function is called by the serdev framework when it accepts
210  * more data being sent.
211  */
212 static void hci_uart_write_wakeup(struct serdev_device *serdev)
213 {
214 	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
215 
216 	BT_DBG("");
217 
218 	if (!hu || serdev != hu->serdev) {
219 		WARN_ON(1);
220 		return;
221 	}
222 
223 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
224 		hci_uart_tx_wakeup(hu);
225 }
226 
227 /** hci_uart_receive_buf - receive buffer wakeup
228  * @serdev: serial device
229  * @data:   pointer to received data
230  * @count:  count of received data in bytes
231  *
232  * This function is called by the serdev framework when it received data
233  * in the RX buffer.
234  *
235  * Return: number of processed bytes
236  */
237 static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
238 				   size_t count)
239 {
240 	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
241 
242 	if (!hu || serdev != hu->serdev) {
243 		WARN_ON(1);
244 		return 0;
245 	}
246 
247 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
248 		return 0;
249 
250 	/* It does not need a lock here as it is already protected by a mutex in
251 	 * tty caller
252 	 */
253 	hu->proto->recv(hu, data, count);
254 
255 	if (hu->hdev)
256 		hu->hdev->stat.byte_rx += count;
257 
258 	return count;
259 }
260 
261 static const struct serdev_device_ops hci_serdev_client_ops = {
262 	.receive_buf = hci_uart_receive_buf,
263 	.write_wakeup = hci_uart_write_wakeup,
264 };
265 
266 int hci_uart_register_device(struct hci_uart *hu,
267 			     const struct hci_uart_proto *p)
268 {
269 	int err;
270 	struct hci_dev *hdev;
271 
272 	BT_DBG("");
273 
274 	serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
275 
276 	err = serdev_device_open(hu->serdev);
277 	if (err)
278 		return err;
279 
280 	err = p->open(hu);
281 	if (err)
282 		goto err_open;
283 
284 	hu->proto = p;
285 	set_bit(HCI_UART_PROTO_READY, &hu->flags);
286 
287 	/* Initialize and register HCI device */
288 	hdev = hci_alloc_dev();
289 	if (!hdev) {
290 		BT_ERR("Can't allocate HCI device");
291 		err = -ENOMEM;
292 		goto err_alloc;
293 	}
294 
295 	hu->hdev = hdev;
296 
297 	hdev->bus = HCI_UART;
298 	hci_set_drvdata(hdev, hu);
299 
300 	INIT_WORK(&hu->init_ready, hci_uart_init_work);
301 	INIT_WORK(&hu->write_work, hci_uart_write_work);
302 	percpu_init_rwsem(&hu->proto_lock);
303 
304 	/* Only when vendor specific setup callback is provided, consider
305 	 * the manufacturer information valid. This avoids filling in the
306 	 * value for Ericsson when nothing is specified.
307 	 */
308 	if (hu->proto->setup)
309 		hdev->manufacturer = hu->proto->manufacturer;
310 
311 	hdev->open  = hci_uart_open;
312 	hdev->close = hci_uart_close;
313 	hdev->flush = hci_uart_flush;
314 	hdev->send  = hci_uart_send_frame;
315 	hdev->setup = hci_uart_setup;
316 	SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
317 
318 	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
319 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
320 
321 	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
322 		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
323 
324 	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
325 		hdev->dev_type = HCI_AMP;
326 	else
327 		hdev->dev_type = HCI_PRIMARY;
328 
329 	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
330 		return 0;
331 
332 	if (hci_register_dev(hdev) < 0) {
333 		BT_ERR("Can't register HCI device");
334 		err = -ENODEV;
335 		goto err_register;
336 	}
337 
338 	set_bit(HCI_UART_REGISTERED, &hu->flags);
339 
340 	return 0;
341 
342 err_register:
343 	hci_free_dev(hdev);
344 err_alloc:
345 	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
346 	p->close(hu);
347 err_open:
348 	serdev_device_close(hu->serdev);
349 	return err;
350 }
351 EXPORT_SYMBOL_GPL(hci_uart_register_device);
352 
353 void hci_uart_unregister_device(struct hci_uart *hu)
354 {
355 	struct hci_dev *hdev = hu->hdev;
356 
357 	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
358 	if (test_bit(HCI_UART_REGISTERED, &hu->flags))
359 		hci_unregister_dev(hdev);
360 	hci_free_dev(hdev);
361 
362 	cancel_work_sync(&hu->write_work);
363 
364 	hu->proto->close(hu);
365 	serdev_device_close(hu->serdev);
366 }
367 EXPORT_SYMBOL_GPL(hci_uart_unregister_device);
368