hci/include/hci_hal.h

/******************************************************************************
 *
 *  Copyright (C) 2014 Google, Inc.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at:
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

#pragma once

#include <stdbool.h>
#include <stdint.h>

#include "osi/include/thread.h"
#include "vendor.h"

typedef enum {
  DATA_TYPE_UNKNOWN = 0,
  DATA_TYPE_COMMAND = 1,
  DATA_TYPE_ACL = 2,
  DATA_TYPE_SCO = 3,
  DATA_TYPE_EVENT = 4
} serial_data_type_t;

typedef void (*data_ready_cb)(serial_data_type_t type);

typedef struct {
  // Called when the HAL detects inbound data.
  // Data |type| may be ACL, SCO, or EVENT.
  // Executes in the context of the thread supplied to |init|.
  data_ready_cb data_ready;

  /*
  // Called when the HAL detects inbound astronauts named Dave.
  // HAL will deny all requests to open the pod bay doors after this.
  dave_ready_cb dave_ready;
  */
} hci_hal_callbacks_t;

typedef struct hci_hal_t {
  // Initialize the HAL, with |upper_callbacks| and |upper_thread| to run in the
  // context of.
  bool (*init)(const hci_hal_callbacks_t* upper_callbacks,
               thread_t* upper_thread);

  // Connect to the underlying hardware, and let data start flowing.
  bool (*open)(void);
  // Disconnect from the underlying hardware, and close the HAL.
  // "Daisy, Daisy..."
  void (*close)(void);

  // Retrieve up to |max_size| bytes for ACL, SCO, or EVENT data packets into
  // |buffer|. Only guaranteed to be correct in the context of a data_ready
  // callback of the corresponding type.
  size_t (*read_data)(serial_data_type_t type, uint8_t* buffer,
                      size_t max_size);
  // The upper layer must call this to notify the HAL that it has finished
  // reading a packet of the specified |type|. Underlying implementations that
  // use shared channels for multiple data types depend on this to know when
  // to reinterpret the data stream.
  void (*packet_finished)(serial_data_type_t type);
  // Transmit COMMAND, ACL, or SCO data packets.
  // |data| may not be NULL. |length| must be greater than zero.
  //
  // IMPORTANT NOTE:
  // Depending on the underlying implementation, the byte right
  // before the beginning of |data| may be borrowed during this call
  // and then restored to its original value.
  // This is safe in the bluetooth context, because there is always a buffer
  // header that prefixes data you're sending.
  uint16_t (*transmit_data)(serial_data_type_t type, uint8_t* data,
                            uint16_t length);
} hci_hal_t;

// Gets the correct hal implementation, as compiled for.
const hci_hal_t* hci_hal_get_interface(void);

const hci_hal_t* hci_hal_h4_get_interface(void);
const hci_hal_t* hci_hal_h4_get_test_interface(vendor_t* vendor_interface);

const hci_hal_t* hci_hal_mct_get_interface(void);
const hci_hal_t* hci_hal_mct_get_test_interface(vendor_t* vendor_interface);