1 /***************************************************************************
2  * Copyright (c) 2024 Microsoft Corporation
3  *
4  * This program and the accompanying materials are made available under the
5  * terms of the MIT License which is available at
6  * https://opensource.org/licenses/MIT.
7  *
8  * SPDX-License-Identifier: MIT
9  **************************************************************************/
10 
11 
12 /**************************************************************************/
13 /**************************************************************************/
14 /**                                                                       */
15 /** USBX Component                                                        */
16 /**                                                                       */
17 /**   EHCI Controller Driver                                              */
18 /**                                                                       */
19 /**************************************************************************/
20 /**************************************************************************/
21 
22 
23 /* Include necessary system files.  */
24 
25 #define UX_SOURCE_CODE
26 
27 #include "ux_api.h"
28 #include "ux_hcd_ehci.h"
29 #include "ux_host_stack.h"
30 
31 
32 /**************************************************************************/
33 /*                                                                        */
34 /*  FUNCTION                                               RELEASE        */
35 /*                                                                        */
36 /*    _ux_hcd_ehci_hsisochronous_td_obtain                PORTABLE C      */
37 /*                                                           6.1          */
38 /*  AUTHOR                                                                */
39 /*                                                                        */
40 /*    Chaoqiong Xiao, Microsoft Corporation                               */
41 /*                                                                        */
42 /*  DESCRIPTION                                                           */
43 /*                                                                        */
44 /*    This function obtains a free TD from the high speed isochronous     */
45 /*    TD list.                                                            */
46 /*                                                                        */
47 /*  INPUT                                                                 */
48 /*                                                                        */
49 /*    hcd_ehci                              Pointer to EHCI controller    */
50 /*                                                                        */
51 /*  OUTPUT                                                                */
52 /*                                                                        */
53 /*    UX_EHCI_HSISO_TD *                    Pointer to EHCI HSISO TD      */
54 /*                                                                        */
55 /*  CALLS                                                                 */
56 /*                                                                        */
57 /*    None                                                                */
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_hsisochronous_td_obtain(UX_HCD_EHCI * hcd_ehci)74 UX_EHCI_HSISO_TD  *_ux_hcd_ehci_hsisochronous_td_obtain(UX_HCD_EHCI *hcd_ehci)
75 {
76 #if UX_MAX_ISO_TD == 0
77 
78     /* This function is not yet supported, return NULL. */
79     UX_PARAMETER_NOT_USED(hcd_ehci);
80     return(UX_NULL);
81 #else
82 
83 UX_EHCI_HSISO_TD    *td;
84 ULONG               td_index;
85 
86 
87     /* Start the search from the beginning of the list.  */
88     td =  hcd_ehci -> ux_hcd_ehci_hsiso_td_list;
89     for (td_index = 0; td_index < _ux_system_host -> ux_system_host_max_iso_td; td_index++)
90     {
91 
92         /* Check the TD status, a free TD is marked with the USED flag.  */
93         if (td -> ux_ehci_hsiso_td_status == UX_UNUSED)
94         {
95 
96             /* The TD may have been used, so we reset all fields.  */
97             _ux_utility_memory_set(td, 0, sizeof(UX_EHCI_HSISO_TD)); /* Use case of memset is verified. */
98 
99             /* This TD is now marked as USED.  */
100             td -> ux_ehci_hsiso_td_status =  UX_USED;
101 
102             /* Initialize the link pointer TD fields.  */
103             td -> ux_ehci_hsiso_td_next_lp.value = UX_EHCI_HSISO_T;
104 
105             /* Success, return TD pointer.  */
106             return(td);
107         }
108 
109         /* Look at next TD.  */
110         td++;
111     }
112 
113     /* There is no available TD in the TD list.  */
114 
115     /* Error, return a null.  */
116     return(UX_NULL);
117 #endif
118 }
119 
120