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common/usbx_device_classes/src/ux_device_class_cdc_acm_read.c
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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** 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 */
/* 6.1.10 */
/* 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_utility_mutex_off Release mutex */
/* */
/* CALLED BY */
/* */
/* ThreadX */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Chaoqiong Xiao Initial Version 6.0 */
/* 09-30-2020 Chaoqiong Xiao Modified comment(s), */
/* verified memset and memcpy */
/* cases, */
/* resulting in version 6.1 */
/* 10-15-2021 Chaoqiong Xiao Modified comment(s), */
/* fixed compile issue, */
/* resulting in version 6.1.9 */
/* 01-31-2022x Chaoqiong Xiao Modified comment(s), */
/* resulting in version 6.1.10 */
/* */
/**************************************************************************/
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;
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 = cdc_acm -> ux_slave_class_cdc_acm_interface;
/* Locate the endpoints. */
endpoint = interface -> 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_utility_mutex_on(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);
/* All CDC reading are on the endpoint OUT, from the host. */
transfer_request = &endpoint -> ux_slave_endpoint_transfer_request;
/* 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_utility_mutex_off(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);
/* Return with success. */
return(UX_SUCCESS);
}
}
else
{
/* Free Mutex resource. */
_ux_utility_mutex_off(&cdc_acm -> ux_slave_class_cdc_acm_endpoint_out_mutex);
/* We got an error. */
return(status);
}
}
/* Free Mutex resource. */
_ux_utility_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);
}
#endif