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