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/**************************************************************************/
/* */
/* 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 */
/** */
/** Host Stack */
/** */
/**************************************************************************/
/**************************************************************************/
/* Include necessary system files. */
#define UX_SOURCE_CODE
#include "ux_api.h"
#include "ux_host_stack.h"
#if UX_MAX_DEVICES > 1
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _ux_host_stack_bandwidth_release PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Chaoqiong Xiao, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function will release bandwidth for a periodic endpoint. The */
/* bandwidth requirement is calculated by the MaxPacketSize field of */
/* endpoint and the speed of the endpoint. If the device is on a 1.1 */
/* bus or it is a 1.1 device behind a 2.0 hub on a 2.0 bus, the device */
/* bandwidth must be multiplied by 8 on the 1.1 segment. */
/* */
/* This algorithm takes into account both TT bandwidth and HCD */
/* bandwidth. The TTs are attached to the device structure and not the */
/* hub structure in order to make the stack agnostic of the hub class. */
/* */
/* INPUT */
/* */
/* HCD Pointer to HCD */
/* endpoint Pointer to endpoint */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* None */
/* */
/* CALLED BY */
/* */
/* USBX Components */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Chaoqiong Xiao Initial Version 6.0 */
/* 09-30-2020 Chaoqiong Xiao Modified comment(s), */
/* optimized based on compile */
/* definitions, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
VOID _ux_host_stack_bandwidth_release(UX_HCD *hcd, UX_ENDPOINT *endpoint)
{
UX_DEVICE *device;
UX_DEVICE *parent_device;
USHORT hcd_bandwidth_claimed;
USHORT max_packet_size;
LONG packet_size;
USHORT tt_bandwidth_claimed = 0;
ULONG port_index;
ULONG port_map;
ULONG tt_index;
const UCHAR overheads[4][3] = {
/* LS FS HS */
{63, 45, 173}, /* Control */
{ 0, 9, 38}, /* Isochronous */
{ 0, 13, 55}, /* Bulk */
{19, 13, 55} /* Interrupt */
};
/* Get the pointer to the device. */
device = endpoint -> ux_endpoint_device;
/* Calculate the bandwidth. From USB spec.
*
* The frame unit consumed per byte is like follow:
* Bytes/FrameUnit FrameUnit/byte FrameUnit/byte
* (Overhead included) (HS baseline) (FS baseline)
* Low Speed 187.5 40 8
* Full Speed 1500 5 1
* High Speed 7500 1 1/5
*
* The overhead is like follow:
* Control Isochronous Bulk Interrupt
* bmAttribute (0) (1) (2) (3)
* Low Speed 63 -- -- 19
* Full Speed 45 9 13 13
* High Speed 173 38 55 55
*
* Worst case bit stuffing is calculated as 1.1667 (7/6) times the raw time.
*/
/* Get maximum packet size. */
max_packet_size = endpoint -> ux_endpoint_descriptor.wMaxPacketSize & UX_MAX_PACKET_SIZE_MASK;
/* Rough time for possible Bit Stuffing. */
packet_size = (max_packet_size * 7 + 5) / 6;
/* Add overhead. */
packet_size += overheads[endpoint -> ux_endpoint_descriptor.bmAttributes & UX_MASK_ENDPOINT_TYPE][device -> ux_device_speed];
max_packet_size = (USHORT)packet_size;
/* Check for high-speed endpoint. */
if (device -> ux_device_speed == UX_HIGH_SPEED_DEVICE)
{
/* Get number of transactions. */
max_packet_size = (USHORT)(max_packet_size *
(((endpoint -> ux_endpoint_descriptor.wMaxPacketSize & UX_MAX_NUMBER_OF_TRANSACTIONS_MASK) >>
UX_MAX_NUMBER_OF_TRANSACTIONS_SHIFT) + 1));
}
/* Calculate the bandwidth claimed by this endpoint for the main bus. */
if (hcd -> ux_hcd_version != 0x200)
{
if (device -> ux_device_speed == UX_LOW_SPEED_DEVICE)
/* Low speed transfer takes 40x more units than high speed. */
hcd_bandwidth_claimed = (USHORT)(max_packet_size * 8 * 5);
else
{
if (device -> ux_device_speed == UX_FULL_SPEED_DEVICE)
/* Full speed transfer takes 5x more units than high speed. */
hcd_bandwidth_claimed = (USHORT)(max_packet_size * 5);
else
/* Use high speed timing as base for bus bandwidth calculation. */
hcd_bandwidth_claimed = (USHORT)max_packet_size;
}
}
else
{
hcd_bandwidth_claimed = (USHORT)max_packet_size;
if (device -> ux_device_speed == UX_LOW_SPEED_DEVICE)
/* Low speed transfer takes 8x more units than full speed. */
tt_bandwidth_claimed = (USHORT)(max_packet_size * 8);
else
/* Use full speed timing as base for TT bandwidth calculation. */
tt_bandwidth_claimed = (USHORT)max_packet_size;
}
/* Free the HCD bandwidth. */
hcd -> ux_hcd_available_bandwidth += hcd_bandwidth_claimed;
/* We need to take care of the case where the endpoint belongs to a USB 1.1
device that sits behind a 2.0 hub. We ignore cases where the device
is either high speed or the bus is 1.1. */
if ((device -> ux_device_speed == UX_HIGH_SPEED_DEVICE) || (hcd -> ux_hcd_version != 0x200))
{
/* The device is high speed, therefore no need for TT. */
return;
}
/* We have a 1.1 device, check if the parent is a 2.0 hub. */
parent_device = device -> ux_device_parent;
if (parent_device == UX_NULL)
{
/* We are at the root, must be a 1.1 controller then! */
return;
}
/* We get here when the parent is a hub. The problem occurs when the hub is itself
connected to a chain of hubs. We need to find the first 2.0 hub parent to this chain
to check the TT. We need to remember the port on which the first 1.1 device is
hooked to. */
port_index = device -> ux_device_port_location - 1;
/* Scan the chain of hubs upward. */
while (parent_device != UX_NULL)
{
/* Check for a high speed device. */
if (parent_device -> ux_device_speed == UX_HIGH_SPEED_DEVICE)
{
/* The device is a high speed hub, find the TT that manages the port.
The first 1.1 device is connected to. First we calculate the port mapping bit. */
port_map = (ULONG)(1 << port_index);
/* Parse all the TTs attached to the hub. */
for (tt_index = 0; tt_index < UX_MAX_TT; tt_index++)
{
/* Check if this TT owns the port where the device is attached. */
if ((parent_device -> ux_device_hub_tt[tt_index].ux_hub_tt_port_mapping & port_map) != 0)
{
/* We have found the port, check if the tt can give us the bandwidth
we want to claim. */
parent_device -> ux_device_hub_tt[tt_index].ux_hub_tt_max_bandwidth += tt_bandwidth_claimed;
return;
}
}
/* We should never get here!!!!! */
return;
}
/* We now remember where this hub is located on the parent. */
port_index = parent_device -> ux_device_port_location - 1;
/* We go up one level in the hub chain. */
parent_device = parent_device -> ux_device_parent;
}
/* We get here when we have not found a 2.0 hub in the list and we got
to the root port. */
return;
}
#endif /* #if UX_MAX_DEVICES > 1 */