Function uart_rx_buf_rsp 

pub unsafe extern "C" fn uart_rx_buf_rsp(
    dev: *const device,
    buf: *mut u8,
    len: usize,
) -> c_int

@brief Provide receive buffer in response to #UART_RX_BUF_REQUEST event.

Provide pointer to RX buffer, which will be used when current buffer is filled.

@note Providing buffer that is already in usage by driver leads to undefined behavior. Buffer can be reused when it has been released by driver.

@param dev UART device instance. @param buf Pointer to receive buffer. @param len Buffer length.

@return 0 on success, negative errno value on failure. @retval -ENOTSUP API is not enabled. @retval -EBUSY Next buffer already set. @retval -EACCES Receiver is already disabled (function called too late?).