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 /** Host Stack */
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_stack.h"
30
31
32 #if UX_MAX_DEVICES > 1
33 /**************************************************************************/
34 /* */
35 /* FUNCTION RELEASE */
36 /* */
37 /* _ux_host_stack_bandwidth_claim PORTABLE C */
38 /* 6.1 */
39 /* AUTHOR */
40 /* */
41 /* Chaoqiong Xiao, Microsoft Corporation */
42 /* */
43 /* DESCRIPTION */
44 /* */
45 /* This function will reserve bandwidth for a periodic endpoint. The */
46 /* bandwidth requirement is calculated by the MaxPacketSize field of */
47 /* endpoint and the speed of the endpoint. If the device is on a 1.1 */
48 /* bus or it is a 1.1 device behind a 2.0 hub on a 2.0 bus, the device */
49 /* bandwidth must be multiplied by 8 on the 1.1 segment. */
50 /* */
51 /* This algorithm takes into account both TT bandwidth and HCD */
52 /* bandwidth. The TTs are attached to the device structure and not */
53 /* the hub structure in order to make the stack agnostic of the hub */
54 /* class. */
55 /* */
56 /* INPUT */
57 /* */
58 /* HCD Pointer to HCD */
59 /* endpoint Pointer to endpoint */
60 /* */
61 /* OUTPUT */
62 /* */
63 /* None */
64 /* */
65 /* CALLS */
66 /* */
67 /* None */
68 /* */
69 /* CALLED BY */
70 /* */
71 /* USBX Components */
72 /* */
73 /* RELEASE HISTORY */
74 /* */
75 /* DATE NAME DESCRIPTION */
76 /* */
77 /* 05-19-2020 Chaoqiong Xiao Initial Version 6.0 */
78 /* 09-30-2020 Chaoqiong Xiao Modified comment(s), */
79 /* optimized based on compile */
80 /* definitions, */
81 /* resulting in version 6.1 */
82 /* */
83 /**************************************************************************/
_ux_host_stack_bandwidth_claim(UX_HCD * hcd,UX_ENDPOINT * endpoint)84 VOID _ux_host_stack_bandwidth_claim(UX_HCD *hcd, UX_ENDPOINT *endpoint)
85 {
86
87 UX_DEVICE *device;
88 UX_DEVICE *parent_device;
89 USHORT hcd_bandwidth_claimed;
90 USHORT max_packet_size;
91 LONG packet_size;
92 USHORT tt_bandwidth_claimed = 0;
93 ULONG port_index;
94 ULONG port_map;
95 ULONG tt_index;
96 const UCHAR overheads[4][3] = {
97 /* LS FS HS */
98 {63, 45, 173}, /* Control */
99 { 0, 9, 38}, /* Isochronous */
100 { 0, 13, 55}, /* Bulk */
101 {19, 13, 55} /* Interrupt */
102 };
103
104 /* Get the pointer to the device. */
105 device = endpoint -> ux_endpoint_device;
106
107 /* Calculate the bandwidth. From USB spec.
108 *
109 * The frame unit consumed per byte is like follow:
110 * Bytes/FrameUnit FrameUnit/byte FrameUnit/byte
111 * (Overhead included) (HS baseline) (FS baseline)
112 * Low Speed 187.5 40 8
113 * Full Speed 1500 5 1
114 * High Speed 7500 1 1/5
115 *
116 * The overhead is like follow:
117 * Control Isochronous Bulk Interrupt
118 * bmAttribute (0) (1) (2) (3)
119 * Low Speed 63 -- -- 19
120 * Full Speed 45 9 13 13
121 * High Speed 173 38 55 55
122 *
123 * Worst case bit stuffing is calculated as 1.1667 (7/6) times the raw time.
124 */
125
126 /* Get maximum packet size. */
127 max_packet_size = endpoint -> ux_endpoint_descriptor.wMaxPacketSize & UX_MAX_PACKET_SIZE_MASK;
128
129 /* Rough time for possible Bit Stuffing. */
130 packet_size = (max_packet_size * 7 + 5) / 6;
131
132 /* Add overhead. */
133 packet_size += overheads[endpoint -> ux_endpoint_descriptor.bmAttributes & UX_MASK_ENDPOINT_TYPE][device -> ux_device_speed];
134 max_packet_size = (USHORT)packet_size;
135
136 /* Check for high-speed endpoint. */
137 if (device -> ux_device_speed == UX_HIGH_SPEED_DEVICE)
138 {
139
140 /* Get number of transactions. */
141 max_packet_size = (USHORT)(max_packet_size *
142 (((endpoint -> ux_endpoint_descriptor.wMaxPacketSize & UX_MAX_NUMBER_OF_TRANSACTIONS_MASK) >>
143 UX_MAX_NUMBER_OF_TRANSACTIONS_SHIFT) + 1));
144 }
145
146 /* Calculate the bandwidth claimed by this endpoint for the main bus. */
147 if (hcd -> ux_hcd_version != 0x200)
148 {
149
150 if (device -> ux_device_speed == UX_LOW_SPEED_DEVICE)
151 /* Low speed transfer takes 40x more units than high speed. */
152 hcd_bandwidth_claimed = (USHORT)(max_packet_size * 8 * 5);
153 else
154 {
155
156 if (device -> ux_device_speed == UX_FULL_SPEED_DEVICE)
157 /* Full speed transfer takes 5x more units than high speed. */
158 hcd_bandwidth_claimed = (USHORT)(max_packet_size * 5);
159 else
160 /* Use high speed timing as base for bus bandwidth calculation. */
161 hcd_bandwidth_claimed = (USHORT)max_packet_size;
162 }
163 }
164 else
165 {
166
167 hcd_bandwidth_claimed = (USHORT)max_packet_size;
168 if (device -> ux_device_speed == UX_LOW_SPEED_DEVICE)
169 /* Low speed transfer takes 8x more units than full speed. */
170 tt_bandwidth_claimed = (USHORT)(max_packet_size * 8);
171 else
172 /* Use full speed timing as base for TT bandwidth calculation. */
173 tt_bandwidth_claimed = (USHORT)max_packet_size;
174 }
175
176 /* Allocate the HCD bandwidth, since it's already checked by _bandwidth_check. */
177 hcd -> ux_hcd_available_bandwidth -= hcd_bandwidth_claimed;
178
179 /* We need to take care of the case where the endpoint belongs to a USB 1.1
180 device that sits behind a 2.0 hub. We ignore cases where the device
181 is either high speed or the bus is 1.1. */
182 if ((device -> ux_device_speed == UX_HIGH_SPEED_DEVICE) || (hcd -> ux_hcd_version != 0x200))
183 {
184
185 /* The device is high speed, therefore no need for TT. */
186 return;
187 }
188
189 /* We have a 1.1 device, check if the parent is a 2.0 hub. */
190 parent_device = device -> ux_device_parent;
191 if (parent_device == UX_NULL)
192 {
193
194 /* We are at the root, must be a 1.1 controller then! */
195 return;
196 }
197
198 /* We get here when the parent is a hub. The problem occurs when the hub is
199 itself connected to a chain of hubs. We need to find the first 2.0 hub
200 parent to this chain to check the TT. We need to remember the port on
201 which the first 1.1 device is hooked to. */
202 port_index = device -> ux_device_port_location - 1;
203
204 /* Scan the chain of hubs upward. */
205 while (parent_device != UX_NULL)
206 {
207
208 /* Is the device high speed? */
209 if (parent_device -> ux_device_speed == UX_HIGH_SPEED_DEVICE)
210 {
211
212 /* The device is a high speed hub, find the TT that manages the port.
213 The first 1.1 device is connected to. First we calculate the port
214 mapping bit. */
215 port_map = (ULONG)(1 << port_index);
216
217 /* Parse all the TTs attached to the hub.
218 Since we confirmed exist of TT in previous _check,
219 just do while loop here.
220 */
221 tt_index = 0;
222 while(1)
223 {
224 /* Check if this TT owns the port where the device is attached. */
225 if ((parent_device -> ux_device_hub_tt[tt_index].ux_hub_tt_port_mapping & port_map) != 0)
226 {
227
228 /* We have found the port, check if the tt can give us the bandwidth
229 we want to claim. */
230 parent_device -> ux_device_hub_tt[tt_index].ux_hub_tt_max_bandwidth -= tt_bandwidth_claimed;
231 return;
232 }
233
234 /* Try next index. */
235 tt_index ++;
236 }
237 }
238
239 /* We now remember where this hub is located on the parent. */
240 port_index = parent_device -> ux_device_port_location - 1;
241
242 /* We go up one level in the hub chain. */
243 parent_device = parent_device -> ux_device_parent;
244 }
245
246 /* We get here when we have not found a 2.0 hub in the list and we got
247 to the root port. */
248 return;
249 }
250 #endif /* #if UX_MAX_DEVICES > 1 */
251
