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 /** Video Class */
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_host_class_video.h"
30 #include "ux_host_stack.h"
31
32
33 /**************************************************************************/
34 /* */
35 /* FUNCTION RELEASE */
36 /* */
37 /* _ux_host_class_video_alternate_setting_locate PORTABLE C */
38 /* 6.1.12 */
39 /* AUTHOR */
40 /* */
41 /* Chaoqiong Xiao, Microsoft Corporation */
42 /* */
43 /* DESCRIPTION */
44 /* */
45 /* This function finds the alternate setting for the specific format. */
46 /* */
47 /* INPUT */
48 /* */
49 /* video Pointer to video class */
50 /* alternate_setting Pointer to located alternate */
51 /* setting */
52 /* */
53 /* OUTPUT */
54 /* */
55 /* Completion Status */
56 /* */
57 /* CALLS */
58 /* */
59 /* _ux_system_error_handler Log system error */
60 /* */
61 /* CALLED BY */
62 /* */
63 /* Video Class */
64 /* */
65 /* RELEASE HISTORY */
66 /* */
67 /* DATE NAME DESCRIPTION */
68 /* */
69 /* 05-19-2020 Chaoqiong Xiao Initial Version 6.0 */
70 /* 09-30-2020 Chaoqiong Xiao Modified comment(s), */
71 /* resulting in version 6.1 */
72 /* 10-15-2021 Chaoqiong Xiao Modified comment(s), */
73 /* use pre-calculated value */
74 /* instead of wMaxPacketSize, */
75 /* resulting in version 6.1.9 */
76 /* 07-29-2022 Chaoqiong Xiao Modified comment(s), */
77 /* fixed parameter/variable */
78 /* names conflict C++ keyword, */
79 /* resulting in version 6.1.12 */
80 /* */
81 /**************************************************************************/
_ux_host_class_video_alternate_setting_locate(UX_HOST_CLASS_VIDEO * video,UINT max_payload_size,UINT * alternate_setting)82 UINT _ux_host_class_video_alternate_setting_locate(UX_HOST_CLASS_VIDEO *video, UINT max_payload_size, UINT *alternate_setting)
83 {
84
85 UX_CONFIGURATION *configuration;
86 UX_INTERFACE *interface_ptr;
87 UX_ENDPOINT *endpoint;
88 UINT streaming_interface;
89 UINT payload_size;
90 UINT current_payload_size = 0;
91 UINT alternate_setting_found;
92
93
94 configuration = video -> ux_host_class_video_streaming_interface -> ux_interface_configuration;
95 interface_ptr = configuration -> ux_configuration_first_interface;
96 streaming_interface = video -> ux_host_class_video_streaming_interface -> ux_interface_descriptor.bInterfaceNumber;
97
98 alternate_setting_found = UX_FALSE;
99
100 /* Scan all interfaces. */
101 while (interface_ptr != UX_NULL)
102 {
103
104 /* Search for the streaming interface with a endpoint. */
105 if ((interface_ptr -> ux_interface_descriptor.bInterfaceNumber == streaming_interface) &&
106 (interface_ptr -> ux_interface_first_endpoint != 0))
107 {
108
109 /* Get the max packet size of the endpoint. */
110 endpoint = interface_ptr -> ux_interface_first_endpoint;
111 payload_size = endpoint -> ux_endpoint_transfer_request.ux_transfer_request_packet_length;
112
113 /* Check if the payload size is equal or greater than the required payload size. */
114 if (payload_size >= max_payload_size)
115 {
116
117 /* Check if we have found any alternate settings yet. */
118 if(alternate_setting_found == UX_FALSE)
119 {
120
121 /* Save the current payload size and mark the found flag. */
122 alternate_setting_found = UX_TRUE;
123 current_payload_size = payload_size;
124
125 /* Save the found alternate setting number. */
126 *alternate_setting = interface_ptr -> ux_interface_descriptor.bAlternateSetting;
127 }
128 else
129 {
130
131 /* Check if the payload size is smaller. */
132 if (payload_size < current_payload_size)
133 {
134
135 /* Smaller payload size found, select the current setting. */
136 current_payload_size = payload_size;
137
138 /* Save the found alternate setting number. */
139 *alternate_setting = interface_ptr -> ux_interface_descriptor.bAlternateSetting;
140 }
141 }
142 }
143 }
144
145 /* Move to next interface. */
146 interface_ptr = interface_ptr -> ux_interface_next_interface;
147 }
148
149 /* Check if we found the alternate setting. */
150 if (alternate_setting_found)
151 {
152
153 /* Return successful completion. */
154 return(UX_SUCCESS);
155 }
156
157 /* Error trap. */
158 _ux_system_error_handler(UX_SYSTEM_LEVEL_THREAD, UX_SYSTEM_CONTEXT_CLASS, UX_HOST_CLASS_VIDEO_WRONG_TYPE);
159
160 /* We get here when either the report descriptor has a problem or we could
161 not find the right video device. */
162 return(UX_HOST_CLASS_VIDEO_WRONG_TYPE);
163 }
164
