drivers/bluetooth/hci_serdev.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  Bluetooth HCI serdev driver lib
0004  *
0005  *  Copyright (C) 2017  Linaro, Ltd., Rob Herring <robh@kernel.org>
0006  *
0007  *  Based on hci_ldisc.c:
0008  *
0009  *  Copyright (C) 2000-2001  Qualcomm Incorporated
0010  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
0011  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
0012  */
0013
0014 #include <linux/kernel.h>
0015 #include <linux/types.h>
0016 #include <linux/serdev.h>
0017 #include <linux/skbuff.h>
0018
0019 #include <net/bluetooth/bluetooth.h>
0020 #include <net/bluetooth/hci_core.h>
0021
0022 #include "hci_uart.h"
0023
0024 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
0025 {
0026     struct hci_dev *hdev = hu->hdev;
0027
0028     /* Update HCI stat counters */
0029     switch (pkt_type) {
0030     case HCI_COMMAND_PKT:
0031         hdev->stat.cmd_tx++;
0032         break;
0033
0034     case HCI_ACLDATA_PKT:
0035         hdev->stat.acl_tx++;
0036         break;
0037
0038     case HCI_SCODATA_PKT:
0039         hdev->stat.sco_tx++;
0040         break;
0041     }
0042 }
0043
0044 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
0045 {
0046     struct sk_buff *skb = hu->tx_skb;
0047
0048     if (!skb) {
0049         if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
0050             skb = hu->proto->dequeue(hu);
0051     } else
0052         hu->tx_skb = NULL;
0053
0054     return skb;
0055 }
0056
0057 static void hci_uart_write_work(struct work_struct *work)
0058 {
0059     struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
0060     struct serdev_device *serdev = hu->serdev;
0061     struct hci_dev *hdev = hu->hdev;
0062     struct sk_buff *skb;
0063
0064     /* REVISIT:
0065      * should we cope with bad skbs or ->write() returning an error value?
0066      */
0067     do {
0068         clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
0069
0070         while ((skb = hci_uart_dequeue(hu))) {
0071             int len;
0072
0073             len = serdev_device_write_buf(serdev,
0074                               skb->data, skb->len);
0075             hdev->stat.byte_tx += len;
0076
0077             skb_pull(skb, len);
0078             if (skb->len) {
0079                 hu->tx_skb = skb;
0080                 break;
0081             }
0082
0083             hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
0084             kfree_skb(skb);
0085         }
0086
0087         clear_bit(HCI_UART_SENDING, &hu->tx_state);
0088     } while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));
0089 }
0090
0091 /* ------- Interface to HCI layer ------ */
0092
0093 /* Reset device */
0094 static int hci_uart_flush(struct hci_dev *hdev)
0095 {
0096     struct hci_uart *hu  = hci_get_drvdata(hdev);
0097
0098     BT_DBG("hdev %p serdev %p", hdev, hu->serdev);
0099
0100     if (hu->tx_skb) {
0101         kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
0102     }
0103
0104     /* Flush any pending characters in the driver and discipline. */
0105     serdev_device_write_flush(hu->serdev);
0106
0107     if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
0108         hu->proto->flush(hu);
0109
0110     return 0;
0111 }
0112
0113 /* Initialize device */
0114 static int hci_uart_open(struct hci_dev *hdev)
0115 {
0116     struct hci_uart *hu = hci_get_drvdata(hdev);
0117     int err;
0118
0119     BT_DBG("%s %p", hdev->name, hdev);
0120
0121     /* When Quirk HCI_QUIRK_NON_PERSISTENT_SETUP is set by
0122      * driver, BT SoC is completely turned OFF during
0123      * BT OFF. Upon next BT ON UART port should be opened.
0124      */
0125     if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
0126         err = serdev_device_open(hu->serdev);
0127         if (err)
0128             return err;
0129         set_bit(HCI_UART_PROTO_READY, &hu->flags);
0130     }
0131
0132     /* Undo clearing this from hci_uart_close() */
0133     hdev->flush = hci_uart_flush;
0134
0135     return 0;
0136 }
0137
0138 /* Close device */
0139 static int hci_uart_close(struct hci_dev *hdev)
0140 {
0141     struct hci_uart *hu = hci_get_drvdata(hdev);
0142
0143     BT_DBG("hdev %p", hdev);
0144
0145     if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
0146         return 0;
0147
0148     hci_uart_flush(hdev);
0149     hdev->flush = NULL;
0150
0151     /* When QUIRK HCI_QUIRK_NON_PERSISTENT_SETUP is set by driver,
0152      * BT SOC is completely powered OFF during BT OFF, holding port
0153      * open may drain the battery.
0154      */
0155     if (test_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks)) {
0156         clear_bit(HCI_UART_PROTO_READY, &hu->flags);
0157         serdev_device_close(hu->serdev);
0158     }
0159
0160     return 0;
0161 }
0162
0163 /* Send frames from HCI layer */
0164 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
0165 {
0166     struct hci_uart *hu = hci_get_drvdata(hdev);
0167
0168     BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
0169            skb->len);
0170
0171     hu->proto->enqueue(hu, skb);
0172
0173     hci_uart_tx_wakeup(hu);
0174
0175     return 0;
0176 }
0177
0178 static int hci_uart_setup(struct hci_dev *hdev)
0179 {
0180     struct hci_uart *hu = hci_get_drvdata(hdev);
0181     struct hci_rp_read_local_version *ver;
0182     struct sk_buff *skb;
0183     unsigned int speed;
0184     int err;
0185
0186     /* Init speed if any */
0187     if (hu->init_speed)
0188         speed = hu->init_speed;
0189     else if (hu->proto->init_speed)
0190         speed = hu->proto->init_speed;
0191     else
0192         speed = 0;
0193
0194     if (speed)
0195         serdev_device_set_baudrate(hu->serdev, speed);
0196
0197     /* Operational speed if any */
0198     if (hu->oper_speed)
0199         speed = hu->oper_speed;
0200     else if (hu->proto->oper_speed)
0201         speed = hu->proto->oper_speed;
0202     else
0203         speed = 0;
0204
0205     if (hu->proto->set_baudrate && speed) {
0206         err = hu->proto->set_baudrate(hu, speed);
0207         if (err)
0208             bt_dev_err(hdev, "Failed to set baudrate");
0209         else
0210             serdev_device_set_baudrate(hu->serdev, speed);
0211     }
0212
0213     if (hu->proto->setup)
0214         return hu->proto->setup(hu);
0215
0216     if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
0217         return 0;
0218
0219     skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
0220                  HCI_INIT_TIMEOUT);
0221     if (IS_ERR(skb)) {
0222         bt_dev_err(hdev, "Reading local version info failed (%ld)",
0223                PTR_ERR(skb));
0224         return 0;
0225     }
0226
0227     if (skb->len != sizeof(*ver))
0228         bt_dev_err(hdev, "Event length mismatch for version info");
0229
0230     kfree_skb(skb);
0231     return 0;
0232 }
0233
0234 /* Check if the device is wakeable */
0235 static bool hci_uart_wakeup(struct hci_dev *hdev)
0236 {
0237     /* HCI UART devices are assumed to be wakeable by default.
0238      * Implement wakeup callback to override this behavior.
0239      */
0240     return true;
0241 }
0242
0243 /** hci_uart_write_wakeup - transmit buffer wakeup
0244  * @serdev: serial device
0245  *
0246  * This function is called by the serdev framework when it accepts
0247  * more data being sent.
0248  */
0249 static void hci_uart_write_wakeup(struct serdev_device *serdev)
0250 {
0251     struct hci_uart *hu = serdev_device_get_drvdata(serdev);
0252
0253     BT_DBG("");
0254
0255     if (!hu || serdev != hu->serdev) {
0256         WARN_ON(1);
0257         return;
0258     }
0259
0260     if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
0261         hci_uart_tx_wakeup(hu);
0262 }
0263
0264 /** hci_uart_receive_buf - receive buffer wakeup
0265  * @serdev: serial device
0266  * @data:   pointer to received data
0267  * @count:  count of received data in bytes
0268  *
0269  * This function is called by the serdev framework when it received data
0270  * in the RX buffer.
0271  *
0272  * Return: number of processed bytes
0273  */
0274 static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
0275                    size_t count)
0276 {
0277     struct hci_uart *hu = serdev_device_get_drvdata(serdev);
0278
0279     if (!hu || serdev != hu->serdev) {
0280         WARN_ON(1);
0281         return 0;
0282     }
0283
0284     if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
0285         return 0;
0286
0287     /* It does not need a lock here as it is already protected by a mutex in
0288      * tty caller
0289      */
0290     hu->proto->recv(hu, data, count);
0291
0292     if (hu->hdev)
0293         hu->hdev->stat.byte_rx += count;
0294
0295     return count;
0296 }
0297
0298 static const struct serdev_device_ops hci_serdev_client_ops = {
0299     .receive_buf = hci_uart_receive_buf,
0300     .write_wakeup = hci_uart_write_wakeup,
0301 };
0302
0303 int hci_uart_register_device(struct hci_uart *hu,
0304                  const struct hci_uart_proto *p)
0305 {
0306     int err;
0307     struct hci_dev *hdev;
0308
0309     BT_DBG("");
0310
0311     serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
0312
0313     err = serdev_device_open(hu->serdev);
0314     if (err)
0315         return err;
0316
0317     percpu_init_rwsem(&hu->proto_lock);
0318
0319     err = p->open(hu);
0320     if (err)
0321         goto err_open;
0322
0323     hu->proto = p;
0324     set_bit(HCI_UART_PROTO_READY, &hu->flags);
0325
0326     /* Initialize and register HCI device */
0327     hdev = hci_alloc_dev();
0328     if (!hdev) {
0329         BT_ERR("Can't allocate HCI device");
0330         err = -ENOMEM;
0331         goto err_alloc;
0332     }
0333
0334     hu->hdev = hdev;
0335
0336     hdev->bus = HCI_UART;
0337     hci_set_drvdata(hdev, hu);
0338
0339     INIT_WORK(&hu->init_ready, hci_uart_init_work);
0340     INIT_WORK(&hu->write_work, hci_uart_write_work);
0341
0342     /* Only when vendor specific setup callback is provided, consider
0343      * the manufacturer information valid. This avoids filling in the
0344      * value for Ericsson when nothing is specified.
0345      */
0346     if (hu->proto->setup)
0347         hdev->manufacturer = hu->proto->manufacturer;
0348
0349     hdev->open  = hci_uart_open;
0350     hdev->close = hci_uart_close;
0351     hdev->flush = hci_uart_flush;
0352     hdev->send  = hci_uart_send_frame;
0353     hdev->setup = hci_uart_setup;
0354     if (!hdev->wakeup)
0355         hdev->wakeup = hci_uart_wakeup;
0356     SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
0357
0358     if (test_bit(HCI_UART_NO_SUSPEND_NOTIFIER, &hu->flags))
0359         set_bit(HCI_QUIRK_NO_SUSPEND_NOTIFIER, &hdev->quirks);
0360
0361     if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
0362         set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
0363
0364     if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
0365         set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
0366
0367     if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
0368         hdev->dev_type = HCI_AMP;
0369     else
0370         hdev->dev_type = HCI_PRIMARY;
0371
0372     if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
0373         return 0;
0374
0375     if (hci_register_dev(hdev) < 0) {
0376         BT_ERR("Can't register HCI device");
0377         err = -ENODEV;
0378         goto err_register;
0379     }
0380
0381     set_bit(HCI_UART_REGISTERED, &hu->flags);
0382
0383     return 0;
0384
0385 err_register:
0386     hci_free_dev(hdev);
0387 err_alloc:
0388     clear_bit(HCI_UART_PROTO_READY, &hu->flags);
0389     p->close(hu);
0390 err_open:
0391     serdev_device_close(hu->serdev);
0392     return err;
0393 }
0394 EXPORT_SYMBOL_GPL(hci_uart_register_device);
0395
0396 void hci_uart_unregister_device(struct hci_uart *hu)
0397 {
0398     struct hci_dev *hdev = hu->hdev;
0399
0400     cancel_work_sync(&hu->init_ready);
0401     if (test_bit(HCI_UART_REGISTERED, &hu->flags))
0402         hci_unregister_dev(hdev);
0403     hci_free_dev(hdev);
0404
0405     cancel_work_sync(&hu->write_work);
0406
0407     hu->proto->close(hu);
0408
0409     if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
0410         clear_bit(HCI_UART_PROTO_READY, &hu->flags);
0411         serdev_device_close(hu->serdev);
0412     }
0413 }
0414 EXPORT_SYMBOL_GPL(hci_uart_unregister_device);