/***************************************************************************
 * Copyright (c) 2024 Microsoft Corporation
 * Copyright (c) 2026-present Eclipse ThreadX contributors
 *
 * This program and the accompanying materials are made available under the
 * terms of the MIT License which is available at
 * https://opensource.org/licenses/MIT.
 *
 * SPDX-License-Identifier: MIT
 **************************************************************************/

/**************************************************************************/
/**************************************************************************/
/**                                                                       */
/** USBX Component                                                        */
/**                                                                       */
/**   Device CDC Class                                                    */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/

#define UX_SOURCE_CODE


/* Include necessary system files.  */

#include "ux_api.h"
#include "ux_device_class_cdc_acm.h"
#include "ux_device_stack.h"


#if !defined(UX_DEVICE_STANDALONE)
/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _ux_device_class_cdc_acm_read                       PORTABLE C      */
/*                                                           6.3.0        */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Chaoqiong Xiao, Microsoft Corporation                               */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function reads from the CDC class.                             */
/*                                                                        */
/*    It's for RTOS mode.                                                 */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    cdc_acm                                   Address of cdc_acm class  */
/*                                              instance                  */
/*    buffer                                    Pointer to buffer to save */
/*                                              received data             */
/*    requested_length                          Length of bytes to read   */
/*    actual_length                             Pointer to save number of */
/*                                              bytes read                */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    _ux_device_stack_transfer_request     Transfer request              */
/*    _ux_utility_memory_copy               Copy memory                   */
/*    _ux_device_mutex_off                  Release mutex                 */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    Application                                                         */
/*                                                                        */
/**************************************************************************/
UINT _ux_device_class_cdc_acm_read(UX_SLAVE_CLASS_CDC_ACM *cdc_acm, UCHAR *buffer,
                                ULONG requested_length, ULONG *actual_length)
{

UX_SLAVE_ENDPOINT           *endpoint;
UX_SLAVE_DEVICE             *device;
UX_SLAVE_INTERFACE          *interface_ptr;
UX_SLAVE_TRANSFER           *transfer_request;
UINT                        status= UX_SUCCESS;
ULONG                       local_requested_length;

    /* If trace is enabled, insert this event into the trace buffer.  */
    UX_TRACE_IN_LINE_INSERT(UX_TRACE_DEVICE_CLASS_CDC_ACM_READ, cdc_acm, buffer, requested_length, 0, UX_TRACE_DEVICE_CLASS_EVENTS, 0, 0)

#ifndef UX_DEVICE_CLASS_CDC_ACM_TRANSMISSION_DISABLE

    /* Check if current cdc-acm is using callback or not. We cannot use direct reads with callback on.  */
    if (cdc_acm -> ux_slave_class_cdc_acm_transmission_status == UX_TRUE)

        /* Not allowed. */
        return(UX_ERROR);
#endif

    /* Get the pointer to the device.  */
    device =  &_ux_system_slave -> ux_system_slave_device;

    /* As long as the device is in the CONFIGURED state.  */
    if (device -> ux_slave_device_state != UX_DEVICE_CONFIGURED)
    {

        /* Error trap. */
        _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_CONFIGURATION_HANDLE_UNKNOWN);


        /* If trace is enabled, insert this event into the trace buffer.  */
        UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_CONFIGURATION_HANDLE_UNKNOWN, device, 0, 0, UX_TRACE_ERRORS, 0, 0)

        /* Cannot proceed with command, the interface is down.  */
        return(UX_CONFIGURATION_HANDLE_UNKNOWN);
    }

    /* This is the first time we are activated. We need the interface to the class.  */
    interface_ptr =  cdc_acm -> ux_slave_class_cdc_acm_interface;

    /* Locate the endpoints.  */
    endpoint =  interface_ptr -> ux_slave_interface_first_endpoint;

    /* Check the endpoint direction, if OUT we have the correct endpoint.  */
    if ((endpoint -> ux_slave_endpoint_descriptor.bEndpointAddress & UX_ENDPOINT_DIRECTION) != UX_ENDPOINT_OUT)
    {

        /* So the next endpoint has to be the OUT endpoint.  */
        endpoint =  endpoint -> ux_slave_endpoint_next_endpoint;
    }

    /* Protect this thread.  */
    _ux_device_mutex_on(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);

    /* All CDC readings are on the endpoint OUT, from the host.  */
    transfer_request =  &endpoint -> ux_slave_endpoint_transfer_request;

#if UX_DEVICE_ENDPOINT_BUFFER_OWNER == 1
#if !defined(UX_DEVICE_CLASS_CDC_ACM_ZERO_COPY)
    transfer_request -> ux_slave_transfer_request_data_pointer =
                                UX_DEVICE_CLASS_CDC_ACM_READ_BUFFER(cdc_acm);
#else
    transfer_request -> ux_slave_transfer_request_data_pointer = buffer;
#endif
#endif

#if (UX_DEVICE_ENDPOINT_BUFFER_OWNER == 1) && defined(UX_DEVICE_CLASS_CDC_ACM_ZERO_COPY)

    /* Check if device is configured.  */
    if (device -> ux_slave_device_state == UX_DEVICE_CONFIGURED)
    {

        /* Issue the transfer request.  */
        local_requested_length = requested_length;
        status = _ux_device_stack_transfer_request(transfer_request, requested_length, local_requested_length);
        *actual_length = transfer_request -> ux_slave_transfer_request_actual_length;
    }

#else

    /* Reset the actual length.  */
    *actual_length =  0;

    /* Check if we need more transactions.  */
    while (device -> ux_slave_device_state == UX_DEVICE_CONFIGURED && requested_length != 0)
    {

        /* Check if we have enough in the local buffer.  */
        if (requested_length > endpoint -> ux_slave_endpoint_descriptor.wMaxPacketSize)

            /* We have too much to transfer.  */
            local_requested_length = endpoint -> ux_slave_endpoint_descriptor.wMaxPacketSize;

        else

            /* We can proceed with the demanded length.  */
            local_requested_length = requested_length;

        /* Send the request to the device controller.  */
        status =  _ux_device_stack_transfer_request(transfer_request, local_requested_length, local_requested_length);

        /* Check the status */
        if (status == UX_SUCCESS)
        {

            /* We need to copy the buffer locally.  */
            _ux_utility_memory_copy(buffer, transfer_request -> ux_slave_transfer_request_data_pointer,
                            transfer_request -> ux_slave_transfer_request_actual_length); /* Use case of memcpy is verified. */

            /* Next buffer address.  */
            buffer += transfer_request -> ux_slave_transfer_request_actual_length;

            /* Set the length actually received. */
            *actual_length += transfer_request -> ux_slave_transfer_request_actual_length;

            /* Decrement what left has to be done.  */
            requested_length -= transfer_request -> ux_slave_transfer_request_actual_length;


            /* Is this a short packet or a ZLP indicating we are done with this transfer ?  */
            if (transfer_request -> ux_slave_transfer_request_actual_length < endpoint -> ux_slave_endpoint_descriptor.wMaxPacketSize)
            {

                /* We are done.  */
                /* Free Mutex resource.  */
                _ux_device_mutex_off(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);

                /* Return with success.  */
                return(UX_SUCCESS);

            }
        }
        else
        {

            /* Free Mutex resource.  */
            _ux_device_mutex_off(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);

            /* We got an error.  */
            return(status);
        }
    }

#endif

    /* Free Mutex resource.  */
    _ux_device_mutex_off(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);

    /* Check why we got here, either completion or device was extracted.  */
    if (device -> ux_slave_device_state != UX_DEVICE_CONFIGURED)
    {

        /* Error trap. */
        _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_TRANSFER_NO_ANSWER);

        /* If trace is enabled, insert this event into the trace buffer.  */
        UX_TRACE_IN_LINE_INSERT(UX_TRACE_ERROR, UX_TRANSFER_NO_ANSWER, transfer_request, 0, 0, UX_TRACE_ERRORS, 0, 0)

        /* Device must have been extracted.  */
        return (UX_TRANSFER_NO_ANSWER);
    }
    else

        /* Simply return the last transaction result.  */
        return(status);
}

/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _uxe_device_class_cdc_acm_read                      PORTABLE C      */
/*                                                           6.3.0        */
/*  AUTHOR                                                                */
/*                                                                        */
/*    Yajun Xia, Microsoft Corporation                                    */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function checks errors in CDC ACM class read function.         */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    cdc_acm                                   Address of cdc_acm class  */
/*                                              instance                  */
/*    buffer                                    Pointer to buffer to save */
/*                                              received data             */
/*    requested_length                          Length of bytes to read   */
/*    actual_length                             Pointer to save number of */
/*                                              bytes read                */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    _ux_device_class_cdc_acm_read         CDC ACM class read function   */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    Application                                                         */
/*                                                                        */
/**************************************************************************/
UINT _uxe_device_class_cdc_acm_read(UX_SLAVE_CLASS_CDC_ACM *cdc_acm, UCHAR *buffer,
                                    ULONG requested_length, ULONG *actual_length)
{

    /* Sanity checks.  */
    if ((cdc_acm == UX_NULL) || ((buffer == UX_NULL) && (requested_length > 0)) || (actual_length == UX_NULL))
    {
        return (UX_INVALID_PARAMETER);
    }

    return (_ux_device_class_cdc_acm_read(cdc_acm, buffer, requested_length, actual_length));
}

#endif