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                 skb = hu->proto->dequeue(hu);
  62         else
  63                 hu->tx_skb = NULL;
  64
  65         return skb;
  66 }
  67
  68 static void hci_uart_write_work(struct work_struct *work)
  69 {
  70         struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
  71         struct serdev_device *serdev = hu->serdev;
  72         struct hci_dev *hdev = hu->hdev;
  73         struct sk_buff *skb;
  74
  75         /* REVISIT:
  76          * should we cope with bad skbs or ->write() returning an error value?
  77          */
  78         do {
  79                 clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  80
  81                 while ((skb = hci_uart_dequeue(hu))) {
  82                         int len;
  83
  84                         len = serdev_device_write_buf(serdev,
  85                                                       skb->data, skb->len);
  86                         hdev->stat.byte_tx += len;
  87
  88                         skb_pull(skb, len);
  89                         if (skb->len) {
  90                                 hu->tx_skb = skb;
  91                                 break;
  92                         }
  93
  94                         hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
  95                         kfree_skb(skb);
  96                 }
  97         } while(test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
  98
  99         clear_bit(HCI_UART_SENDING, &hu->tx_state);
 100 }
 101
 102 /* ------- Interface to HCI layer ------ */
 103
 104 /* Reset device */
 105 static int hci_uart_flush(struct hci_dev *hdev)
 106 {
 107         struct hci_uart *hu  = hci_get_drvdata(hdev);
 108
 109         BT_DBG("hdev %p serdev %p", hdev, hu->serdev);
 110
 111         if (hu->tx_skb) {
 112                 kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 113         }
 114
 115         /* Flush any pending characters in the driver and discipline. */
 116         serdev_device_write_flush(hu->serdev);
 117
 118         if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
 119                 hu->proto->flush(hu);
 120
 121         return 0;
 122 }
 123
 124 /* Initialize device */
 125 static int hci_uart_open(struct hci_dev *hdev)
 126 {
 127         BT_DBG("%s %p", hdev->name, hdev);
 128
 129         /* Undo clearing this from hci_uart_close() */
 130         hdev->flush = hci_uart_flush;
 131
 132         return 0;
 133 }
 134
 135 /* Close device */
 136 static int hci_uart_close(struct hci_dev *hdev)
 137 {
 138         BT_DBG("hdev %p", hdev);
 139
 140         hci_uart_flush(hdev);
 141         hdev->flush = NULL;
 142
 143         return 0;
 144 }
 145
 146 /* Send frames from HCI layer */
 147 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 148 {
 149         struct hci_uart *hu = hci_get_drvdata(hdev);
 150
 151         BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
 152                skb->len);
 153
 154         hu->proto->enqueue(hu, skb);
 155
 156         hci_uart_tx_wakeup(hu);
 157
 158         return 0;
 159 }
 160
 161 static int hci_uart_setup(struct hci_dev *hdev)
 162 {
 163         struct hci_uart *hu = hci_get_drvdata(hdev);
 164         struct hci_rp_read_local_version *ver;
 165         struct sk_buff *skb;
 166         unsigned int speed;
 167         int err;
 168
 169         /* Init speed if any */
 170         if (hu->init_speed)
 171                 speed = hu->init_speed;
 172         else if (hu->proto->init_speed)
 173                 speed = hu->proto->init_speed;
 174         else
 175                 speed = 0;
 176
 177         if (speed)
 178                 serdev_device_set_baudrate(hu->serdev, speed);
 179
 180         /* Operational speed if any */
 181         if (hu->oper_speed)
 182                 speed = hu->oper_speed;
 183         else if (hu->proto->oper_speed)
 184                 speed = hu->proto->oper_speed;
 185         else
 186                 speed = 0;
 187
 188         if (hu->proto->set_baudrate && speed) {
 189                 err = hu->proto->set_baudrate(hu, speed);
 190                 if (err)
 191                         bt_dev_err(hdev, "Failed to set baudrate");
 192                 else
 193                         serdev_device_set_baudrate(hu->serdev, speed);
 194         }
 195
 196         if (hu->proto->setup)
 197                 return hu->proto->setup(hu);
 198
 199         if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
 200                 return 0;
 201
 202         skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
 203                              HCI_INIT_TIMEOUT);
 204         if (IS_ERR(skb)) {
 205                 bt_dev_err(hdev, "Reading local version info failed (%ld)",
 206                            PTR_ERR(skb));
 207                 return 0;
 208         }
 209
 210         if (skb->len != sizeof(*ver))
 211                 bt_dev_err(hdev, "Event length mismatch for version info");
 212
 213         kfree_skb(skb);
 214         return 0;
 215 }
 216
 217 /** hci_uart_write_wakeup - transmit buffer wakeup
 218  * @serdev: serial device
 219  *
 220  * This function is called by the serdev framework when it accepts
 221  * more data being sent.
 222  */
 223 static void hci_uart_write_wakeup(struct serdev_device *serdev)
 224 {
 225         struct hci_uart *hu = serdev_device_get_drvdata(serdev);
 226
 227         BT_DBG("");
 228
 229         if (!hu || serdev != hu->serdev) {
 230                 WARN_ON(1);
 231                 return;
 232         }
 233
 234         if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
 235                 hci_uart_tx_wakeup(hu);
 236 }
 237
 238 /** hci_uart_receive_buf - receive buffer wakeup
 239  * @serdev: serial device
 240  * @data:   pointer to received data
 241  * @count:  count of received data in bytes
 242  *
 243  * This function is called by the serdev framework when it received data
 244  * in the RX buffer.
 245  *
 246  * Return: number of processed bytes
 247  */
 248 static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
 249                                    size_t count)
 250 {
 251         struct hci_uart *hu = serdev_device_get_drvdata(serdev);
 252
 253         if (!hu || serdev != hu->serdev) {
 254                 WARN_ON(1);
 255                 return 0;
 256         }
 257
 258         if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
 259                 return 0;
 260
 261         /* It does not need a lock here as it is already protected by a mutex in
 262          * tty caller
 263          */
 264         hu->proto->recv(hu, data, count);
 265
 266         if (hu->hdev)
 267                 hu->hdev->stat.byte_rx += count;
 268
 269         return count;
 270 }
 271
 272 static struct serdev_device_ops hci_serdev_client_ops = {
 273         .receive_buf = hci_uart_receive_buf,
 274         .write_wakeup = hci_uart_write_wakeup,
 275 };
 276
 277 int hci_uart_register_device(struct hci_uart *hu,
 278                              const struct hci_uart_proto *p)
 279 {
 280         int err;
 281         struct hci_dev *hdev;
 282
 283         BT_DBG("");
 284
 285         serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
 286
 287         err = serdev_device_open(hu->serdev);
 288         if (err)
 289                 return err;
 290
 291         err = p->open(hu);
 292         if (err)
 293                 goto err_open;
 294
 295         hu->proto = p;
 296         set_bit(HCI_UART_PROTO_READY, &hu->flags);
 297
 298         /* Initialize and register HCI device */
 299         hdev = hci_alloc_dev();
 300         if (!hdev) {
 301                 BT_ERR("Can't allocate HCI device");
 302                 err = -ENOMEM;
 303                 goto err_alloc;
 304         }
 305
 306         hu->hdev = hdev;
 307
 308         hdev->bus = HCI_UART;
 309         hci_set_drvdata(hdev, hu);
 310
 311         INIT_WORK(&hu->init_ready, hci_uart_init_work);
 312         INIT_WORK(&hu->write_work, hci_uart_write_work);
 313         percpu_init_rwsem(&hu->proto_lock);
 314
 315         /* Only when vendor specific setup callback is provided, consider
 316          * the manufacturer information valid. This avoids filling in the
 317          * value for Ericsson when nothing is specified.
 318          */
 319         if (hu->proto->setup)
 320                 hdev->manufacturer = hu->proto->manufacturer;
 321
 322         hdev->open  = hci_uart_open;
 323         hdev->close = hci_uart_close;
 324         hdev->flush = hci_uart_flush;
 325         hdev->send  = hci_uart_send_frame;
 326         hdev->setup = hci_uart_setup;
 327         SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
 328
 329         if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
 330                 set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
 331
 332         if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
 333                 set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
 334
 335         if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
 336                 set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
 337
 338         if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
 339                 hdev->dev_type = HCI_AMP;
 340         else
 341                 hdev->dev_type = HCI_PRIMARY;
 342
 343         if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
 344                 return 0;
 345
 346         if (hci_register_dev(hdev) < 0) {
 347                 BT_ERR("Can't register HCI device");
 348                 err = -ENODEV;
 349                 goto err_register;
 350         }
 351
 352         set_bit(HCI_UART_REGISTERED, &hu->flags);
 353
 354         return 0;
 355
 356 err_register:
 357         hci_free_dev(hdev);
 358 err_alloc:
 359         clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 360         p->close(hu);
 361 err_open:
 362         serdev_device_close(hu->serdev);
 363         return err;
 364 }
 365 EXPORT_SYMBOL_GPL(hci_uart_register_device);
 366
 367 void hci_uart_unregister_device(struct hci_uart *hu)
 368 {
 369         struct hci_dev *hdev = hu->hdev;
 370
 371         clear_bit(HCI_UART_PROTO_READY, &hu->flags);
 372         hci_unregister_dev(hdev);
 373         hci_free_dev(hdev);
 374
 375         cancel_work_sync(&hu->write_work);
 376
 377         hu->proto->close(hu);
 378         serdev_device_close(hu->serdev);
 379 }
 380 EXPORT_SYMBOL_GPL(hci_uart_unregister_device);