1 /**************************************************************************/
2 /*                                                                        */
3 /*       Copyright (c) Microsoft Corporation. All rights reserved.        */
4 /*                                                                        */
5 /*       This software is licensed under the Microsoft Software License   */
6 /*       Terms for Microsoft Azure RTOS. Full text of the license can be  */
7 /*       found in the LICENSE file at https://aka.ms/AzureRTOS_EULA       */
8 /*       and in the root directory of this software.                      */
9 /*                                                                        */
10 /**************************************************************************/
11 
12 
13 /**************************************************************************/
14 /**************************************************************************/
15 /**                                                                       */
16 /** USBX Component                                                        */
17 /**                                                                       */
18 /**   EHCI Controller Driver                                              */
19 /**                                                                       */
20 /**************************************************************************/
21 /**************************************************************************/
22 
23 
24 /* Include necessary system files.  */
25 
26 #define UX_SOURCE_CODE
27 
28 #include "ux_api.h"
29 #include "ux_hcd_ehci.h"
30 #include "ux_host_stack.h"
31 
32 
33 /**************************************************************************/
34 /*                                                                        */
35 /*  FUNCTION                                               RELEASE        */
36 /*                                                                        */
37 /*    _ux_hcd_ehci_ed_obtain                              PORTABLE C      */
38 /*                                                           6.1          */
39 /*  AUTHOR                                                                */
40 /*                                                                        */
41 /*    Chaoqiong Xiao, Microsoft Corporation                               */
42 /*                                                                        */
43 /*  DESCRIPTION                                                           */
44 /*                                                                        */
45 /*    This function obtains a free ED from the ED list.                   */
46 /*                                                                        */
47 /*  INPUT                                                                 */
48 /*                                                                        */
49 /*    hcd_ehci                              Pointer to EHCI controller    */
50 /*                                                                        */
51 /*  OUTPUT                                                                */
52 /*                                                                        */
53 /*    UX_EHCI_ED *                          Pointer to ED                 */
54 /*                                                                        */
55 /*  CALLS                                                                 */
56 /*                                                                        */
57 /*    _ux_utility_memory_set                Set memory block              */
58 /*                                                                        */
59 /*  CALLED BY                                                             */
60 /*                                                                        */
61 /*    EHCI Controller Driver                                              */
62 /*                                                                        */
63 /*  RELEASE HISTORY                                                       */
64 /*                                                                        */
65 /*    DATE              NAME                      DESCRIPTION             */
66 /*                                                                        */
67 /*  05-19-2020     Chaoqiong Xiao           Initial Version 6.0           */
68 /*  09-30-2020     Chaoqiong Xiao           Modified comment(s),          */
69 /*                                            verified memset and memcpy  */
70 /*                                            cases,                      */
71 /*                                            resulting in version 6.1    */
72 /*                                                                        */
73 /**************************************************************************/
_ux_hcd_ehci_ed_obtain(UX_HCD_EHCI * hcd_ehci)74 UX_EHCI_ED  *_ux_hcd_ehci_ed_obtain(UX_HCD_EHCI *hcd_ehci)
75 {
76 
77 UX_EHCI_ED      *ed;
78 ULONG           ed_index;
79 
80 
81     /* Start the search from the beginning of the list.  */
82     ed =  hcd_ehci -> ux_hcd_ehci_ed_list;
83     for (ed_index = 0; ed_index < _ux_system_host -> ux_system_host_max_ed; ed_index++)
84     {
85 
86         /* Check the ED status, a free ED is marked with the UNUSED flag.  */
87         if (ed -> ux_ehci_ed_status == UX_UNUSED)
88         {
89 
90             /* The ED may have been used, so we reset all fields.  */
91             _ux_utility_memory_set(ed, 0, sizeof(UX_EHCI_ED)); /* Use case of memset is verified. */
92 
93             /* This ED is now marked as USED.  */
94             ed -> ux_ehci_ed_status =  UX_USED;
95 
96             /* We initialize the type of ED and mark its TD terminator to be safe.  */
97             ed -> ux_ehci_ed_queue_head =     (UX_EHCI_ED *) UX_EHCI_QH_TYP_QH;
98             ed -> ux_ehci_ed_queue_element =  (UX_EHCI_TD *) UX_EHCI_TD_T;
99 
100             /* Success, return ED pointer.  */
101             return(ed);
102         }
103 
104         /* Point to the next ED.  */
105         ed++;
106     }
107 
108     /* There is no available ED in the ED list.  */
109     return(UX_NULL);
110 }
111 
112