simmel-bootloader/nRF5_SDK_11.0.0_89a8197/components/libraries/hci/hci_slip.c
2018-02-07 23:32:49 +07:00

429 lines
12 KiB
C

/* Copyright (c) 2013 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
#include "hci_slip.h"
#include <stdlib.h>
#include "hci_transport_config.h"
#include "app_uart.h"
#include "nrf_error.h"
#define APP_SLIP_END 0xC0 /**< SLIP code for identifying the beginning and end of a packet frame.. */
#define APP_SLIP_ESC 0xDB /**< SLIP escape code. This code is used to specify that the following character is specially encoded. */
#define APP_SLIP_ESC_END 0xDC /**< SLIP special code. When this code follows 0xDB, this character is interpreted as payload data 0xC0.. */
#define APP_SLIP_ESC_ESC 0xDD /**< SLIP special code. When this code follows 0xDB, this character is interpreted as payload data 0xDB. */
/** @brief States for the SLIP state machine. */
typedef enum
{
SLIP_OFF, /**< SLIP state OFF. */
SLIP_READY, /**< SLIP state ON. */
SLIP_TRANSMITTING, /**< SLIP state is transmitting indicating write() has been called but data transmission has not completed. */
} slip_states_t;
static slip_states_t m_current_state = SLIP_OFF; /** Current state for the SLIP TX state machine. */
static hci_slip_event_handler_t m_slip_event_handler; /** Event callback function for handling of SLIP events, @ref hci_slip_evt_type_t . */
static const uint8_t * mp_tx_buffer; /** Pointer to the current TX buffer that is in transmission. */
static uint32_t m_tx_buffer_length; /** Length of the current TX buffer that is in transmission. */
static volatile uint32_t m_tx_buffer_index; /** Current index for next byte to transmit in the mp_tx_buffer. */
static uint8_t * mp_rx_buffer; /** Pointer to the current RX buffer where the next SLIP decoded packet will be stored. */
static uint32_t m_rx_buffer_length; /** Length of the current RX buffer. */
static uint32_t m_rx_received_count; /** Number of SLIP decoded bytes received and stored in mp_rx_buffer. */
/**@brief Function for parsing bytes received on the UART until a SLIP escape byte is received.
*
* @param[in] byte Byte received in UART module.
*/
static void handle_rx_byte_default(uint8_t byte);
/**@brief Function for parsing bytes received on the UART until SLIP end byte is received.
*
* @param[in] byte Byte received in UART module.
*/
static void handle_rx_byte_wait_start(uint8_t byte);
/**@brief Function for decoding a received SLIP escape byte.
* It will ensure correct decoding of the byte following the SLIP escape byte.
*
* @param[in] byte Byte received in UART module.
*/
static void handle_rx_byte_esc(uint8_t byte);
/**@brief Function pointer for parsing and decoding SLIP bytes from the UART module.
*
* @param[in] byte Byte received in UART module.
*/
static void (*handle_rx_byte) (uint8_t byte) = handle_rx_byte_wait_start;
/**@brief Function pointer for sending a byte through the UART module.
*/
static uint32_t send_tx_byte_default(void);
/**@brief Function for transferring a SLIP escape byte (0xDB) when special bytes are transferred,
* that is 0xC0 and 0xDB.
*/
static uint32_t send_tx_byte_esc(void);
/**@brief Function for transferring a byte when it collides with SLIP commands and follows the SLIP
* escape byte, that is 0xC0 => 0xDC and 0xDB => 0xDD.
*/
static uint32_t send_tx_byte_encoded(void);
/**@brief Function for transferring the SLIP end frame byte, 0xC0.
*/
static uint32_t send_tx_byte_end(void);
/**@brief Function pointer for sending a byte through the UART module.
*/
uint32_t (*send_tx_byte) (void) = send_tx_byte_default;
static uint32_t send_tx_byte_end(void)
{
uint32_t err_code = app_uart_put(APP_SLIP_END);
if ((err_code == NRF_SUCCESS) && (m_tx_buffer_index == 0))
{
// Packet transmission started.
send_tx_byte = send_tx_byte_default;
}
return err_code;
}
static uint32_t send_tx_byte_default(void)
{
uint32_t err_code = app_uart_put(mp_tx_buffer[m_tx_buffer_index]);
if (err_code == NRF_SUCCESS)
{
m_tx_buffer_index++;
}
return err_code;
}
static uint32_t send_tx_byte_encoded(void)
{
uint32_t err_code;
switch(mp_tx_buffer[m_tx_buffer_index])
{
case APP_SLIP_END:
err_code = app_uart_put(APP_SLIP_ESC_END);
break;
case APP_SLIP_ESC:
err_code = app_uart_put(APP_SLIP_ESC_ESC);
break;
default:
err_code = NRF_ERROR_NO_MEM;
break;
}
if (err_code == NRF_SUCCESS)
{
m_tx_buffer_index++;
send_tx_byte = send_tx_byte_default;
}
return err_code;
}
static uint32_t send_tx_byte_esc(void)
{
uint32_t err_code = app_uart_put(APP_SLIP_ESC);
if (err_code == NRF_SUCCESS)
{
send_tx_byte = send_tx_byte_encoded;
}
return err_code;
}
/** @brief Function for transferring the content of the mp_tx_buffer to the UART.
* It continues to transfer bytes until the UART buffer is full or the complete buffer is
* transferred.
*/
static void transmit_buffer(void)
{
uint32_t err_code = NRF_SUCCESS;
while (m_tx_buffer_index < m_tx_buffer_length)
{
if ((mp_tx_buffer[m_tx_buffer_index] == APP_SLIP_END ||
mp_tx_buffer[m_tx_buffer_index] == APP_SLIP_ESC) &&
send_tx_byte == send_tx_byte_default)
{
send_tx_byte = send_tx_byte_esc;
}
err_code = send_tx_byte();
if (err_code == NRF_ERROR_NO_MEM || err_code == NRF_ERROR_BUSY)
{
// No memory left in UART TX buffer. Abort and wait for APP_UART_TX_EMPTY to continue.
return;
}
}
send_tx_byte = send_tx_byte_end;
err_code = send_tx_byte();
if (err_code == NRF_SUCCESS)
{
// Packet transmission ended. Notify higher level.
m_current_state = SLIP_READY;
if (m_slip_event_handler != NULL)
{
hci_slip_evt_t event = {HCI_SLIP_TX_DONE, mp_tx_buffer, m_tx_buffer_index};
m_slip_event_handler(event);
}
}
}
/** @brief Function for handling the reception of a SLIP end byte.
* If the number of bytes received is greater than zero it will call m_slip_event_handler
* with number of bytes received and invalidate the mp_rx_buffer to protect against data
* corruption.
* No new bytes can be received until a new RX buffer is supplied.
*/
static void handle_slip_end(void)
{
if (m_rx_received_count > 0)
{
// Full packet received, push it up.
if (m_slip_event_handler != NULL)
{
hci_slip_evt_t event = {HCI_SLIP_RX_RDY, mp_rx_buffer, m_rx_received_count};
m_rx_received_count = 0;
mp_rx_buffer = NULL;
m_slip_event_handler(event);
}
}
}
static void handle_rx_byte_esc(uint8_t byte)
{
switch (byte)
{
case APP_SLIP_END:
handle_slip_end();
break;
case APP_SLIP_ESC_END:
mp_rx_buffer[m_rx_received_count++] = APP_SLIP_END;
break;
case APP_SLIP_ESC_ESC:
mp_rx_buffer[m_rx_received_count++] = APP_SLIP_ESC;
break;
default:
mp_rx_buffer[m_rx_received_count++] = byte;
break;
}
handle_rx_byte = handle_rx_byte_default;
}
static void handle_rx_byte_default(uint8_t byte)
{
switch (byte)
{
case APP_SLIP_END:
handle_slip_end();
break;
case APP_SLIP_ESC:
handle_rx_byte = handle_rx_byte_esc;
break;
default:
mp_rx_buffer[m_rx_received_count++] = byte;
break;
}
}
static void handle_rx_byte_wait_start(uint8_t byte)
{
if (byte == APP_SLIP_END)
{
handle_rx_byte = handle_rx_byte_default;
}
}
/** @brief Function for checking the current index and length of the RX buffer to determine if the
* buffer is full. If an event handler has been registered, the callback function will
* be executed..
*
* @retval true If RX buffer has overflowed.
* @retval false otherwise.
*
*/
static bool rx_buffer_overflowed(void)
{
if (mp_rx_buffer == NULL || m_rx_received_count >= m_rx_buffer_length)
{
if (m_slip_event_handler != NULL)
{
hci_slip_evt_t event = {HCI_SLIP_RX_OVERFLOW, mp_rx_buffer, m_rx_received_count};
m_slip_event_handler(event);
}
return true;
}
return false;
}
/** @brief Function for handling the UART module event. It parses events from the UART when
* bytes are received/transmitted.
*
* @param[in] uart_event Event received from app_uart module.
*/
static void slip_uart_eventhandler(app_uart_evt_t * uart_event)
{
if (uart_event->evt_type == APP_UART_TX_EMPTY && m_current_state == SLIP_TRANSMITTING)
{
transmit_buffer();
}
if ((uart_event->evt_type == APP_UART_DATA) && (!rx_buffer_overflowed()))
{
handle_rx_byte(uart_event->data.value);
}
}
/** @brief Function for enabling the UART module when the SLIP layer is opened.
*/
static uint32_t slip_uart_open(void)
{
uint32_t err_code;
app_uart_comm_params_t comm_params =
{
HCI_SLIP_UART_RX_PIN_NUMBER,
HCI_SLIP_UART_TX_PIN_NUMBER,
HCI_SLIP_UART_RTS_PIN_NUMBER,
HCI_SLIP_UART_CTS_PIN_NUMBER,
HCI_SLIP_UART_MODE,
false,
HCI_SLIP_UART_BAUDRATE
};
err_code = app_uart_init(&comm_params,
NULL,
slip_uart_eventhandler,
APP_IRQ_PRIORITY_LOW);
if (err_code == NRF_SUCCESS)
{
m_current_state = SLIP_READY;
}
return err_code;
}
uint32_t hci_slip_evt_handler_register(hci_slip_event_handler_t event_handler)
{
m_slip_event_handler = event_handler;
return NRF_SUCCESS;
}
uint32_t hci_slip_open()
{
switch (m_current_state)
{
case SLIP_OFF:
return slip_uart_open();
default:
// Do nothing.
break;
}
return NRF_SUCCESS;
}
uint32_t hci_slip_close()
{
m_current_state = SLIP_OFF;
uint32_t err_code = app_uart_close();
return err_code;
}
uint32_t hci_slip_write(const uint8_t * p_buffer, uint32_t length)
{
if (p_buffer == NULL)
{
return NRF_ERROR_INVALID_ADDR;
}
switch (m_current_state)
{
case SLIP_READY:
m_tx_buffer_index = 0;
m_tx_buffer_length = length;
mp_tx_buffer = p_buffer;
m_current_state = SLIP_TRANSMITTING;
send_tx_byte = send_tx_byte_end;
transmit_buffer();
return NRF_SUCCESS;
case SLIP_TRANSMITTING:
return NRF_ERROR_NO_MEM;
case SLIP_OFF:
default:
return NRF_ERROR_INVALID_STATE;
}
}
uint32_t hci_slip_rx_buffer_register(uint8_t * p_buffer, uint32_t length)
{
mp_rx_buffer = p_buffer;
m_rx_buffer_length = length;
m_rx_received_count = 0;
handle_rx_byte = handle_rx_byte_wait_start;
return NRF_SUCCESS;
}