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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/* Check if the device is wakeable */
235static bool hci_uart_wakeup(struct hci_dev *hdev)
236{
237 /* HCI UART devices are assumed to be wakeable by default.
238 * Implement wakeup callback to override this behavior.
239 */
240 return true;
241}
242
243/** hci_uart_write_wakeup - transmit buffer wakeup
244 * @serdev: serial device
245 *
246 * This function is called by the serdev framework when it accepts
247 * more data being sent.
248 */
249static void hci_uart_write_wakeup(struct serdev_device *serdev)
250{
251 struct hci_uart *hu = serdev_device_get_drvdata(serdev);
252
253 BT_DBG("");
254
255 if (!hu || serdev != hu->serdev) {
256 WARN_ON(1);
257 return;
258 }
259
260 if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
261 hci_uart_tx_wakeup(hu);
262}
263
264/** hci_uart_receive_buf - receive buffer wakeup
265 * @serdev: serial device
266 * @data: pointer to received data
267 * @count: count of received data in bytes
268 *
269 * This function is called by the serdev framework when it received data
270 * in the RX buffer.
271 *
272 * Return: number of processed bytes
273 */
274static size_t hci_uart_receive_buf(struct serdev_device *serdev,
275 const u8 *data, size_t count)
276{
277 struct hci_uart *hu = serdev_device_get_drvdata(serdev);
278
279 if (!hu || serdev != hu->serdev) {
280 WARN_ON(1);
281 return 0;
282 }
283
284 if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
285 return 0;
286
287 /* It does not need a lock here as it is already protected by a mutex in
288 * tty caller
289 */
290 hu->proto->recv(hu, data, count);
291
292 if (hu->hdev)
293 hu->hdev->stat.byte_rx += count;
294
295 return count;
296}
297
298static const struct serdev_device_ops hci_serdev_client_ops = {
299 .receive_buf = hci_uart_receive_buf,
300 .write_wakeup = hci_uart_write_wakeup,
301};
302
303int hci_uart_register_device_priv(struct hci_uart *hu,
304 const struct hci_uart_proto *p,
305 int sizeof_priv)
306{
307 int err;
308 struct hci_dev *hdev;
309
310 BT_DBG("");
311
312 serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
313
314 if (percpu_init_rwsem(&hu->proto_lock))
315 return -ENOMEM;
316
317 err = serdev_device_open(hu->serdev);
318 if (err)
319 goto err_rwsem;
320
321 err = p->open(hu);
322 if (err)
323 goto err_open;
324
325 hu->proto = p;
326 set_bit(HCI_UART_PROTO_READY, &hu->flags);
327
328 /* Initialize and register HCI device */
329 hdev = hci_alloc_dev_priv(sizeof_priv);
330 if (!hdev) {
331 BT_ERR("Can't allocate HCI device");
332 err = -ENOMEM;
333 goto err_alloc;
334 }
335
336 hu->hdev = hdev;
337
338 hdev->bus = HCI_UART;
339 hci_set_drvdata(hdev, hu);
340
341 INIT_WORK(&hu->init_ready, hci_uart_init_work);
342 INIT_WORK(&hu->write_work, hci_uart_write_work);
343
344 /* Only when vendor specific setup callback is provided, consider
345 * the manufacturer information valid. This avoids filling in the
346 * value for Ericsson when nothing is specified.
347 */
348 if (hu->proto->setup)
349 hdev->manufacturer = hu->proto->manufacturer;
350
351 hdev->open = hci_uart_open;
352 hdev->close = hci_uart_close;
353 hdev->flush = hci_uart_flush;
354 hdev->send = hci_uart_send_frame;
355 hdev->setup = hci_uart_setup;
356 if (!hdev->wakeup)
357 hdev->wakeup = hci_uart_wakeup;
358 SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
359
360 if (test_bit(HCI_UART_NO_SUSPEND_NOTIFIER, &hu->flags))
361 set_bit(HCI_QUIRK_NO_SUSPEND_NOTIFIER, &hdev->quirks);
362
363 if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
364 set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
365
366 if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
367 set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
368
369 if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
370 return 0;
371
372 if (hci_register_dev(hdev) < 0) {
373 BT_ERR("Can't register HCI device");
374 err = -ENODEV;
375 goto err_register;
376 }
377
378 set_bit(HCI_UART_REGISTERED, &hu->flags);
379
380 return 0;
381
382err_register:
383 hci_free_dev(hdev);
384err_alloc:
385 clear_bit(HCI_UART_PROTO_READY, &hu->flags);
386 p->close(hu);
387err_open:
388 serdev_device_close(hu->serdev);
389err_rwsem:
390 percpu_free_rwsem(&hu->proto_lock);
391 return err;
392}
393EXPORT_SYMBOL_GPL(hci_uart_register_device_priv);
394
395void hci_uart_unregister_device(struct hci_uart *hu)
396{
397 struct hci_dev *hdev = hu->hdev;
398
399 cancel_work_sync(&hu->init_ready);
400 if (test_bit(HCI_UART_REGISTERED, &hu->flags))
401 hci_unregister_dev(hdev);
402 hci_free_dev(hdev);
403
404 cancel_work_sync(&hu->write_work);
405
406 hu->proto->close(hu);
407
408 if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
409 clear_bit(HCI_UART_PROTO_READY, &hu->flags);
410 serdev_device_close(hu->serdev);
411 }
412 percpu_free_rwsem(&hu->proto_lock);
413}
414EXPORT_SYMBOL_GPL(hci_uart_unregister_device);