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/***************************************************************************
* 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 */
/** */
/** EHCI Controller Driver */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_hcd_ehci.h"
#include "ux_host_stack.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_hcd_ehci_regular_td_obtain PORTABLE C */
/* 6.1.11 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function obtains a free TD from the regular TD list. */
/* */
/* INPUT */
/* */
/* hcd_ehci Pointer to EHCI controller */
/* */
/* OUTPUT */
/* */
/* UX_EHCI_TD * Pointer to TD */
/* */
/* CALLS */
/* */
/* _ux_utility_memory_set Set memory block */
/* _ux_host_mutex_on Get protection mutex */
/* _ux_host_mutex_off Release protection mutex */
/* */
/* CALLED BY */
/* */
/* EHCI Controller Driver */
/* */
/**************************************************************************/
UX_EHCI_TD *_ux_hcd_ehci_regular_td_obtain(UX_HCD_EHCI *hcd_ehci)
{
UX_EHCI_TD *td;
ULONG td_index;
ULONG td_element;
/* Get the mutex as this is a critical section. */
_ux_host_mutex_on(&_ux_system -> ux_system_mutex);
/* Start the search from the beginning of the list. */
td = hcd_ehci -> ux_hcd_ehci_td_list;
for (td_index = 0; td_index < _ux_system_host -> ux_system_host_max_td; td_index++)
{
/* Check the TD status, a free TD is marked with the USED flag. */
if (td -> ux_ehci_td_status == UX_UNUSED)
{
/* The TD may have been used, so we reset all fields. */
_ux_utility_memory_set(td, 0, sizeof(UX_EHCI_TD)); /* Use case of memset is verified. */
/* This TD is now marked as USED. */
td -> ux_ehci_td_status = UX_USED;
/* Initialize the link pointer and alternate TD fields. */
td_element = UX_EHCI_TD_T;
td -> ux_ehci_td_link_pointer = (UX_EHCI_TD *) td_element;
td -> ux_ehci_td_alternate_link_pointer = (UX_EHCI_TD *) td_element;
/* Release the protection. */
_ux_host_mutex_off(&_ux_system -> ux_system_mutex);
/* Success, return TD pointer. */
return(td);
}
/* Look at next TD. */
td++;
}
/* There is no available TD in the TD list. */
/* Release protection. */
_ux_host_mutex_off(&_ux_system -> ux_system_mutex);
/* Error, return a null. */
return(UX_NULL);
}
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