/**************************************************************************/ /* */ /* 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 */ /** */ /** 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 */ /* */ /* 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 */ /* 04-25-2022 Chaoqiong Xiao Modified comment(s), */ /* fixed standalone compile, */ /* resulting in version 6.1.11 */ /* */ /**************************************************************************/ 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); }