drivers/bluetooth/hci_serdev.c

   1 /*
   2  *  Bluetooth HCI serdev driver lib
   3  *
   4  *  Copyright (C) 2017  Linaro, Ltd., Rob Herring <robh@kernel.org>
   5  *
   6  *  Based on hci_ldisc.c:
   7  *
   8  *  Copyright (C) 2000-2001  Qualcomm Incorporated
   9  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
  10  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or
  15  *  (at your option) any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/types.h>
  26 #include <linux/serdev.h>
  27 #include <linux/skbuff.h>
  28
  29 #include <net/bluetooth/bluetooth.h>
  30 #include <net/bluetooth/hci_core.h>
  31
  32 #include "hci_uart.h"
  33
  34 static struct serdev_device_ops hci_serdev_client_ops;
  35
  36 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
  37 {
  38         struct hci_dev *hdev = hu->hdev;
  39
  40         /* Update HCI stat counters */
  41         switch (pkt_type) {
  42         case HCI_COMMAND_PKT:
  43                 hdev->stat.cmd_tx++;
  44                 break;
  45
  46         case HCI_ACLDATA_PKT:
  47                 hdev->stat.acl_tx++;
  48                 break;
  49
  50         case HCI_SCODATA_PKT:
  51                 hdev->stat.sco_tx++;
  52                 break;
  53         }
  54 }
  55
  56 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
  57 {
  58         struct sk_buff *skb = hu->tx_skb;
  59
  60         if (!skb) {
  61                 if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  62                         skb = hu->proto->dequeue(hu);
  63         } else
  64                 hu->tx_skb = NULL;
  65
  66         return skb;
  67 }
  68
  69 static void hci_uart_write_work(struct work_struct *work)
  70 {
  71         struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
  72         struct serdev_device *serdev = hu->serdev;
  73         struct hci_dev *hdev = hu->hdev;
  74         struct sk_buff *skb;
  75
  76         /* REVISIT:
  77          * should we cope with bad skbs or ->write() returning an error value?
  78          */
  79         do {
  80                 clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  81
  82                 while ((skb = hci_uart_dequeue(hu))) {
  83                         int len;
  84
  85                         len = serdev_device_write_buf(serdev,
  86                                                       skb->data, skb->len);
  87                         hdev->stat.byte_tx += len;
  88
  89                         skb_pull(skb, len);
  90                         if (skb->len) {
  91                                 hu->tx_skb = skb;
  92                                 break;
  93                         }
  94
  95                         hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
  96                         kfree_skb(skb);
  97                 }
  98         } while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
  99
 100         clear_bit(HCI_UART_SENDING, &hu->tx_state);
 101 }
 102
 103 /* ------- Interface to HCI layer ------ */
 104
 105 /* Reset device */
 106 static int hci_uart_flush(struct hci_dev *hdev)
 107 {
 108         struct hci_uart *hu  = hci_get_drvdata(hdev);
 109
 110         BT_DBG("hdev %p serdev %p", hdev, hu->serdev);
 111
 112         if (hu->tx_skb) {
 113                 kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 114         }
 115
 116         /* Flush any pending characters in the driver and discipline. */
 117         serdev_device_write_flush(hu->serdev);
 118
 119         if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
 120                 hu->proto->flush(hu);
 121
 122         return 0;
 123 }
 124
 125 /* Initialize device */
 126 static int hci_uart_open(struct hci_dev *hdev)
 127 {
 128         BT_DBG("%s %p", hdev->name, hdev);
 129
 130         /* Undo clearing this from hci_uart_close() */
 131         hdev->flush = hci_uart_flush;
 132
 133         return 0;
 134 }
 135
 136 /* Close device */
 137 static int hci_uart_close(struct hci_dev *hdev)
 138 {
 139         BT_DBG("hdev %p", hdev);
 140
 141         hci_uart_flush(hdev);
 142         hdev->flush = NULL;
 143
 144         return 0;
 145 }
 146
 147 /* Send frames from HCI layer */
 148 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 149 {
 150         struct hci_uart *hu = hci_get_drvdata(hdev);
 151
 152         BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
 153                skb->len);
 154
 155         hu->proto->enqueue(hu, skb);
 156
 157         hci_uart_tx_wakeup(hu);
 158
 159         return 0;
 160 }
 161
 162 static int hci_uart_setup(struct hci_dev *hdev)
 163 {
 164         struct hci_uart *hu = hci_get_drvdata(hdev);
 165         struct hci_rp_read_local_version *ver;
 166         struct sk_buff *skb;
 167         unsigned int speed;
 168         int err;
 169
 170         /* Init speed if any */
 171         if (hu->init_speed)
 172                 speed = hu->init_speed;
 173         else if (hu->proto->init_speed)
 174                 speed = hu->proto->init_speed;
 175         else
 176                 speed = 0;
 177
 178         if (speed)
 179                 serdev_device_set_baudrate(hu->serdev, speed);
 180
 181         /* Operational speed if any */
 182         if (hu->oper_speed)
 183                 speed = hu->oper_speed;
 184         else if (hu->proto->oper_speed)
 185                 speed = hu->proto->oper_speed;
 186         else
 187                 speed = 0;
 188
 189         if (hu->proto->set_baudrate && speed) {
 190                 err = hu->proto->set_baudrate(hu, speed);
 191                 if (err)
 192                         bt_dev_err(hdev, "Failed to set baudrate");
 193                 else
 194                         serdev_device_set_baudrate(hu->serdev, speed);
 195         }
 196
 197         if (hu->proto->setup)
 198                 return hu->proto->setup(hu);
 199
 200         if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
 201                 return 0;
 202
 203         skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
 204                              HCI_INIT_TIMEOUT);
 205         if (IS_ERR(skb)) {
 206                 bt_dev_err(hdev, "Reading local version info failed (%ld)",
 207                            PTR_ERR(skb));
 208                 return 0;
 209         }
 210
 211         if (skb->len != sizeof(*ver))
 212                 bt_dev_err(hdev, "Event length mismatch for version info");
 213
 214         kfree_skb(skb);
 215         return 0;
 216 }
 217
 218 /** hci_uart_write_wakeup - transmit buffer wakeup
 219  * @serdev: serial device
 220  *
 221  * This function is called by the serdev framework when it accepts
 222  * more data being sent.
 223  */
 224 static void hci_uart_write_wakeup(struct serdev_device *serdev)
 225 {
 226         struct hci_uart *hu = serdev_device_get_drvdata(serdev);
 227
 228         BT_DBG("");
 229
 230         if (!hu || serdev != hu->serdev) {
 231                 WARN_ON(1);
 232                 return;
 233         }
 234
 235         if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
 236                 hci_uart_tx_wakeup(hu);
 237 }
 238
 239 /** hci_uart_receive_buf - receive buffer wakeup
 240  * @serdev: serial device
 241  * @data:   pointer to received data
 242  * @count:  count of received data in bytes
 243  *
 244  * This function is called by the serdev framework when it received data
 245  * in the RX buffer.
 246  *
 247  * Return: number of processed bytes
 248  */
 249 static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
 250                                    size_t count)
 251 {
 252         struct hci_uart *hu = serdev_device_get_drvdata(serdev);
 253
 254         if (!hu || serdev != hu->serdev) {
 255                 WARN_ON(1);
 256                 return 0;
 257         }
 258
 259         if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
 260                 return 0;
 261
 262         /* It does not need a lock here as it is already protected by a mutex in
 263          * tty caller
 264          */
 265         hu->proto->recv(hu, data, count);
 266
 267         if (hu->hdev)
 268                 hu->hdev->stat.byte_rx += count;
 269
 270         return count;
 271 }
 272
 273 static struct serdev_device_ops hci_serdev_client_ops = {
 274         .receive_buf = hci_uart_receive_buf,
 275         .write_wakeup = hci_uart_write_wakeup,
 276 };
 277
 278 int hci_uart_register_device(struct hci_uart *hu,
 279                              const struct hci_uart_proto *p)
 280 {
 281         int err;
 282         struct hci_dev *hdev;
 283
 284         BT_DBG("");
 285
 286         serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
 287
 288         err = serdev_device_open(hu->serdev);
 289         if (err)
 290                 return err;
 291
 292         err = p->open(hu);
 293         if (err)
 294                 goto err_open;
 295
 296         hu->proto = p;
 297         set_bit(HCI_UART_PROTO_READY, &hu->flags);
 298
 299         /* Initialize and register HCI device */
 300         hdev = hci_alloc_dev();
 301         if (!hdev) {
 302                 BT_ERR("Can't allocate HCI device");
 303                 err = -ENOMEM;
 304                 goto err_alloc;
 305         }
 306
 307         hu->hdev = hdev;
 308
 309         hdev->bus = HCI_UART;
 310         hci_set_drvdata(hdev, hu);
 311
 312         INIT_WORK(&hu->init_ready, hci_uart_init_work);
 313         INIT_WORK(&hu->write_work, hci_uart_write_work);
 314         percpu_init_rwsem(&hu->proto_lock);
 315
 316         /* Only when vendor specific setup callback is provided, consider
 317          * the manufacturer information valid. This avoids filling in the
 318          * value for Ericsson when nothing is specified.
 319          */
 320         if (hu->proto->setup)
 321                 hdev->manufacturer = hu->proto->manufacturer;
 322
 323         hdev->open  = hci_uart_open;
 324         hdev->close = hci_uart_close;
 325         hdev->flush = hci_uart_flush;
 326         hdev->send  = hci_uart_send_frame;
 327         hdev->setup = hci_uart_setup;
 328         SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
 329
 330         if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
 331                 set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
 332
 333         if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
 334                 set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
 335
 336         if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
 337                 hdev->dev_type = HCI_AMP;
 338         else
 339                 hdev->dev_type = HCI_PRIMARY;
 340
 341         if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
 342                 return 0;
 343
 344         if (hci_register_dev(hdev) < 0) {
 345                 BT_ERR("Can't register HCI device");
 346                 err = -ENODEV;
 347                 goto err_register;
 348         }
 349
 350         set_bit(HCI_UART_REGISTERED, &hu->flags);
 351
 352         return 0;
 353
 354 err_register:
 355         hci_free_dev(hdev);
 356 err_alloc:
 357         clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 358         p->close(hu);
 359 err_open:
 360         serdev_device_close(hu->serdev);
 361         return err;
 362 }
 363 EXPORT_SYMBOL_GPL(hci_uart_register_device);
 364
 365 void hci_uart_unregister_device(struct hci_uart *hu)
 366 {
 367         struct hci_dev *hdev = hu->hdev;
 368
 369         clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 370         hci_unregister_dev(hdev);
 371         hci_free_dev(hdev);
 372
 373         cancel_work_sync(&hu->write_work);
 374
 375         hu->proto->close(hu);
 376         serdev_device_close(hu->serdev);
 377 }
 378 EXPORT_SYMBOL_GPL(hci_uart_unregister_device);