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