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
24static 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
44static 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
57static 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
87		clear_bit(HCI_UART_SENDING, &hu->tx_state);
88	} while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
89}
90
91/* ------- Interface to HCI layer ------ */
92
93/* Reset device */
94static 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 */
114static int hci_uart_open(struct hci_dev *hdev)
115{
116	struct hci_uart *hu = hci_get_drvdata(hdev);
117	int err;
118
119	BT_DBG("%s %p", hdev->name, hdev);
120
121	/* When Quirk HCI_QUIRK_NON_PERSISTENT_SETUP is set by
122	 * driver, BT SoC is completely turned OFF during
123	 * BT OFF. Upon next BT ON UART port should be opened.
124	 */
125	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
126		err = serdev_device_open(hu->serdev);
127		if (err)
128			return err;
129		set_bit(HCI_UART_PROTO_READY, &hu->flags);
130	}
131
132	/* Undo clearing this from hci_uart_close() */
133	hdev->flush = hci_uart_flush;
134
135	return 0;
136}
137
138/* Close device */
139static int hci_uart_close(struct hci_dev *hdev)
140{
141	struct hci_uart *hu = hci_get_drvdata(hdev);
142
143	BT_DBG("hdev %p", hdev);
144
145	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
146		return 0;
147
148	hci_uart_flush(hdev);
149	hdev->flush = NULL;
150
151	/* When QUIRK HCI_QUIRK_NON_PERSISTENT_SETUP is set by driver,
152	 * BT SOC is completely powered OFF during BT OFF, holding port
153	 * open may drain the battery.
154	 */
155	if (test_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks)) {
156		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
157		serdev_device_close(hu->serdev);
158	}
159
160	return 0;
161}
162
163/* Send frames from HCI layer */
164static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
165{
166	struct hci_uart *hu = hci_get_drvdata(hdev);
167
168	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
169	       skb->len);
170
171	hu->proto->enqueue(hu, skb);
172
173	hci_uart_tx_wakeup(hu);
174
175	return 0;
176}
177
178static int hci_uart_setup(struct hci_dev *hdev)
179{
180	struct hci_uart *hu = hci_get_drvdata(hdev);
181	struct hci_rp_read_local_version *ver;
182	struct sk_buff *skb;
183	unsigned int speed;
184	int err;
185
186	/* Init speed if any */
187	if (hu->init_speed)
188		speed = hu->init_speed;
189	else if (hu->proto->init_speed)
190		speed = hu->proto->init_speed;
191	else
192		speed = 0;
193
194	if (speed)
195		serdev_device_set_baudrate(hu->serdev, speed);
196
197	/* Operational speed if any */
198	if (hu->oper_speed)
199		speed = hu->oper_speed;
200	else if (hu->proto->oper_speed)
201		speed = hu->proto->oper_speed;
202	else
203		speed = 0;
204
205	if (hu->proto->set_baudrate && speed) {
206		err = hu->proto->set_baudrate(hu, speed);
207		if (err)
208			bt_dev_err(hdev, "Failed to set baudrate");
209		else
210			serdev_device_set_baudrate(hu->serdev, speed);
211	}
212
213	if (hu->proto->setup)
214		return hu->proto->setup(hu);
215
216	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
217		return 0;
218
219	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
220			     HCI_INIT_TIMEOUT);
221	if (IS_ERR(skb)) {
222		bt_dev_err(hdev, "Reading local version info failed (%ld)",
223			   PTR_ERR(skb));
224		return 0;
225	}
226
227	if (skb->len != sizeof(*ver))
228		bt_dev_err(hdev, "Event length mismatch for version info");
229
230	kfree_skb(skb);
231	return 0;
232}
233
234/** hci_uart_write_wakeup - transmit buffer wakeup
235 * @serdev: serial device
236 *
237 * This function is called by the serdev framework when it accepts
238 * more data being sent.
239 */
240static void hci_uart_write_wakeup(struct serdev_device *serdev)
241{
242	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
243
244	BT_DBG("");
245
246	if (!hu || serdev != hu->serdev) {
247		WARN_ON(1);
248		return;
249	}
250
251	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
252		hci_uart_tx_wakeup(hu);
253}
254
255/** hci_uart_receive_buf - receive buffer wakeup
256 * @serdev: serial device
257 * @data:   pointer to received data
258 * @count:  count of received data in bytes
259 *
260 * This function is called by the serdev framework when it received data
261 * in the RX buffer.
262 *
263 * Return: number of processed bytes
264 */
265static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
266				   size_t count)
267{
268	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
269
270	if (!hu || serdev != hu->serdev) {
271		WARN_ON(1);
272		return 0;
273	}
274
275	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
276		return 0;
277
278	/* It does not need a lock here as it is already protected by a mutex in
279	 * tty caller
280	 */
281	hu->proto->recv(hu, data, count);
282
283	if (hu->hdev)
284		hu->hdev->stat.byte_rx += count;
285
286	return count;
287}
288
289static const struct serdev_device_ops hci_serdev_client_ops = {
290	.receive_buf = hci_uart_receive_buf,
291	.write_wakeup = hci_uart_write_wakeup,
292};
293
294int hci_uart_register_device(struct hci_uart *hu,
295			     const struct hci_uart_proto *p)
296{
297	int err;
298	struct hci_dev *hdev;
299
300	BT_DBG("");
301
302	serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
303
304	if (percpu_init_rwsem(&hu->proto_lock))
305		return -ENOMEM;
306
307	err = serdev_device_open(hu->serdev);
308	if (err)
309		goto err_rwsem;
310
311	err = p->open(hu);
312	if (err)
313		goto err_open;
314
315	hu->proto = p;
316	set_bit(HCI_UART_PROTO_READY, &hu->flags);
317
318	/* Initialize and register HCI device */
319	hdev = hci_alloc_dev();
320	if (!hdev) {
321		BT_ERR("Can't allocate HCI device");
322		err = -ENOMEM;
323		goto err_alloc;
324	}
325
326	hu->hdev = hdev;
327
328	hdev->bus = HCI_UART;
329	hci_set_drvdata(hdev, hu);
330
331	INIT_WORK(&hu->init_ready, hci_uart_init_work);
332	INIT_WORK(&hu->write_work, hci_uart_write_work);
333
334	/* Only when vendor specific setup callback is provided, consider
335	 * the manufacturer information valid. This avoids filling in the
336	 * value for Ericsson when nothing is specified.
337	 */
338	if (hu->proto->setup)
339		hdev->manufacturer = hu->proto->manufacturer;
340
341	hdev->open  = hci_uart_open;
342	hdev->close = hci_uart_close;
343	hdev->flush = hci_uart_flush;
344	hdev->send  = hci_uart_send_frame;
345	hdev->setup = hci_uart_setup;
346	SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
347
348	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
349		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
350
351	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
352		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
353
354	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
355		hdev->dev_type = HCI_AMP;
356	else
357		hdev->dev_type = HCI_PRIMARY;
358
359	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
360		return 0;
361
362	if (hci_register_dev(hdev) < 0) {
363		BT_ERR("Can't register HCI device");
364		err = -ENODEV;
365		goto err_register;
366	}
367
368	set_bit(HCI_UART_REGISTERED, &hu->flags);
369
370	return 0;
371
372err_register:
373	hci_free_dev(hdev);
374err_alloc:
375	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
376	p->close(hu);
377err_open:
378	serdev_device_close(hu->serdev);
379err_rwsem:
380	percpu_free_rwsem(&hu->proto_lock);
381	return err;
382}
383EXPORT_SYMBOL_GPL(hci_uart_register_device);
384
385void hci_uart_unregister_device(struct hci_uart *hu)
386{
387	struct hci_dev *hdev = hu->hdev;
388
389	cancel_work_sync(&hu->init_ready);
390	if (test_bit(HCI_UART_REGISTERED, &hu->flags))
391		hci_unregister_dev(hdev);
392	hci_free_dev(hdev);
393
394	cancel_work_sync(&hu->write_work);
395
396	hu->proto->close(hu);
397
398	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
399		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
400		serdev_device_close(hu->serdev);
401	}
402	percpu_free_rwsem(&hu->proto_lock);
403}
404EXPORT_SYMBOL_GPL(hci_uart_unregister_device);
405