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usb-firewall-fork/Downstream/Src/downstream_hid.c

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/*
* downstream_hid.c
*
* Created on: Apr 10, 2016
* Author: Robert Fisk
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*/
#include "downstream_hid.h"
#include "downstream_statemachine.h"
#include "usbh_hid.h"
#include "stm32f4xx_hal.h"
#define HID_MAX_REPORT_LEN 8
#define HID_MOUSE_DATA_LEN 4
#define HID_KEYBOARD_DATA_LEN 0
#define HID_MOUSE_MAX_BUTTONS 4
extern USBH_HandleTypeDef hUsbHostFS; //Hard-link ourselves to usb_host.c
extern InterfaceCommandClassTypeDef ConfiguredDeviceClass; //Do a cheap hard-link to downstream_statemachine.c, rather than keep a duplicate here
//Information required to extract the data we need from incoming device reports.
uint8_t ReportButtonBitOffset;
uint8_t ReportButtonBitLength;
uint8_t ReportXBitOffset;
uint8_t ReportXBitLength;
uint8_t ReportYBitOffset;
uint8_t ReportYBitLength;
uint8_t ReportWheelBitOffset;
uint8_t ReportWheelBitLength;
//Stuff used while parsing HID report
uint8_t* ReportDataPointer;
uint8_t ItemHeader;
uint8_t ItemData;
static HAL_StatusTypeDef Downstream_HID_Mouse_ParseReportDescriptor(void);
static HAL_StatusTypeDef Downstream_HID_GetNextReportItem(void);
static void Downstream_HID_Mouse_ExtractDataFromReport(DownstreamPacketTypeDef* packetToSend);
static uint8_t Downstream_HID_Mouse_Extract8BitValue(HID_HandleTypeDef* hidHandle,
uint8_t valueBitOffset,
uint8_t valueBitLength);
InterfaceCommandClassTypeDef Downstream_HID_ApproveConnectedDevice(void)
{
HID_HandleTypeDef* HID_Handle = (HID_HandleTypeDef*)hUsbHostFS.pActiveClass->pData;
if (HID_Handle->Protocol != HID_MOUSE_BOOT_CODE)
{
return COMMAND_CLASS_INTERFACE; //fail
}
if (Downstream_HID_Mouse_ParseReportDescriptor() != HAL_OK)
{
return COMMAND_CLASS_INTERFACE; //fail
}
return COMMAND_CLASS_HID_MOUSE; //success!
}
HAL_StatusTypeDef Downstream_HID_Mouse_ParseReportDescriptor(void)
{
uint32_t currentReportBitIndex = 0;
uint8_t currentUsagePage = 0;
uint8_t currentUsageIndex = 0;
uint8_t xUsageIndex = 0xFF;
uint8_t yUsageIndex = 0xFF;
uint8_t wheelUsageIndex = 0xFF;
uint8_t currentReportSize = 0;
uint8_t currentReportCount = 0;
ReportDataPointer = hUsbHostFS.device.Data;
ReportButtonBitLength = 0;
ReportXBitLength = 0;
ReportYBitLength = 0;
ReportWheelBitLength = 0;
while ((Downstream_HID_GetNextReportItem() == HAL_OK) && ((ReportButtonBitLength == 0) ||
(ReportXBitLength == 0) ||
(ReportYBitLength == 0) ||
(ReportWheelBitLength == 0)))
{
switch (ItemHeader)
{
case HID_ITEM_USAGE_PAGE:
currentUsagePage = ItemData;
currentUsageIndex = 0;
xUsageIndex = 0xFF;
yUsageIndex = 0xFF;
wheelUsageIndex = 0xFF;
break;
case HID_ITEM_COLLECTION: //Physical collections also clear the usage index...
if (ItemData == HID_ITEM_COLLECTION_PHYS)
{
currentUsageIndex = 0;
xUsageIndex = 0xFF;
yUsageIndex = 0xFF;
wheelUsageIndex = 0xFF;
}
break;
case HID_ITEM_END_COLLECTION: //...and so do collection ends
currentUsageIndex = 0;
xUsageIndex = 0xFF;
yUsageIndex = 0xFF;
wheelUsageIndex = 0xFF;
break;
case HID_ITEM_USAGE:
switch (ItemData)
{
case HID_ITEM_USAGE_X:
xUsageIndex = currentUsageIndex;
break;
case HID_ITEM_USAGE_Y:
yUsageIndex = currentUsageIndex;
break;
case HID_ITEM_USAGE_WHEEL:
wheelUsageIndex = currentUsageIndex;
break;
}
currentUsageIndex++;
break;
case HID_ITEM_REPORT_SIZE:
currentReportSize = ItemData;
break;
case HID_ITEM_REPORT_COUNT:
currentReportCount = ItemData;
break;
case HID_ITEM_INPUT:
switch (currentUsagePage)
{
case HID_ITEM_USAGE_PAGE_BUTTON:
if (ItemData == HID_ITEM_INPUT_ABS)
{
//Buttons found!
if (currentReportSize != 1)
{
return HAL_ERROR;
}
ReportButtonBitOffset = currentReportBitIndex;
ReportButtonBitLength = currentReportCount;
if (ReportButtonBitLength > HID_MOUSE_MAX_BUTTONS)
{
ReportButtonBitLength = HID_MOUSE_MAX_BUTTONS;
}
}
break;
case HID_ITEM_USAGE_PAGE_DESKTOP:
if (ItemData == HID_ITEM_INPUT_REL)
{
//Movement data found!
if ((currentReportSize < 8) || (currentReportSize > 16))
{
return HAL_ERROR;
}
if (xUsageIndex != 0xFF)
{
ReportXBitOffset = currentReportBitIndex + (currentReportSize * xUsageIndex);
ReportXBitLength = currentReportSize;
if ((ReportXBitOffset + ReportXBitLength) > (HID_MAX_REPORT_LEN * 8))
{
return HAL_ERROR;
}
}
if (yUsageIndex != 0xFF)
{
ReportYBitOffset = currentReportBitIndex + (currentReportSize * yUsageIndex);
ReportYBitLength = currentReportSize;
if ((ReportYBitOffset + ReportYBitLength) > (HID_MAX_REPORT_LEN * 8))
{
return HAL_ERROR;
}
}
if (wheelUsageIndex != 0xFF)
{
ReportWheelBitOffset = currentReportBitIndex + (currentReportSize * wheelUsageIndex);
ReportWheelBitLength = currentReportSize;
if ((ReportWheelBitOffset + ReportWheelBitLength) > (HID_MAX_REPORT_LEN * 8))
{
return HAL_ERROR;
}
}
}
break;
}
currentUsageIndex = 0;
xUsageIndex = 0xFF;
yUsageIndex = 0xFF;
wheelUsageIndex = 0xFF;
currentReportBitIndex += (currentReportSize * currentReportCount);
break;
}
}
//We don't mind if we didn't find a scrollwheel item.
if ((ReportButtonBitLength == 0) ||
(ReportXBitLength == 0) ||
(ReportYBitLength == 0))
{
return HAL_ERROR;
}
return HAL_OK;
}
//Retrieves the next item in the HID report, and at most one of its associated data bytes.
//Then it updates ReportDataPointer based on the actual length of the retrieved item.
HAL_StatusTypeDef Downstream_HID_GetNextReportItem(void)
{
HID_HandleTypeDef* HID_Handle = (HID_HandleTypeDef*)hUsbHostFS.pActiveClass->pData;
uint32_t itemLength;
if ((ReportDataPointer >= &hUsbHostFS.device.Data[USBH_MAX_DATA_BUFFER]) ||
((ReportDataPointer - &hUsbHostFS.device.Data[0]) >= HID_Handle->HID_Desc.wItemLength))
{
return HAL_ERROR;
}
ItemHeader = *ReportDataPointer++;
itemLength = ItemHeader & HID_ITEM_LENGTH_MASK;
if (ItemHeader == HID_ITEM_LONG)
{
itemLength += *ReportDataPointer; //Long items have another length byte
}
else
{
if (itemLength > 0)
{
ItemData = *ReportDataPointer; //If it is a short item, grab its first data byte
}
}
ReportDataPointer += itemLength;
return HAL_OK;
}
void Downstream_HID_PacketProcessor(DownstreamPacketTypeDef* receivedPacket)
{
if (receivedPacket->Command != COMMAND_HID_REPORT)
{
Downstream_PacketProcessor_FreakOut();
return;
}
Downstream_ReleasePacket(receivedPacket);
if (USBH_HID_GetInterruptReport(&hUsbHostFS,
Downstream_HID_InterruptReportCallback) != HAL_OK)
{
Downstream_PacketProcessor_FreakOut();
}
Downstream_PacketProcessor_NotifyDisconnectReplyRequired();
}
void Downstream_HID_InterruptReportCallback(DownstreamPacketTypeDef* packetToSend)
{
if (ConfiguredDeviceClass == COMMAND_CLASS_HID_MOUSE)
{
Downstream_HID_Mouse_ExtractDataFromReport(packetToSend);
packetToSend->Length16 = ((HID_MOUSE_DATA_LEN + 1) / 2) + DOWNSTREAM_PACKET_HEADER_LEN_16;
}
//else if...
else
{
Downstream_PacketProcessor_FreakOut();
return;
}
packetToSend->CommandClass = ConfiguredDeviceClass;
packetToSend->Command = COMMAND_HID_REPORT;
Downstream_PacketProcessor_ClassReply(packetToSend);
}
void Downstream_HID_Mouse_ExtractDataFromReport(DownstreamPacketTypeDef* packetToSend)
{
HID_HandleTypeDef* HID_Handle = (HID_HandleTypeDef*)hUsbHostFS.pActiveClass->pData;
uint32_t readData;
readData = *(uint32_t*)&(HID_Handle->Data[(ReportButtonBitOffset / 8)]);
readData >>= (ReportButtonBitOffset % 8);
readData &= ((1 << ReportButtonBitLength) - 1); //Truncate extra buttons
packetToSend->Data[0] = readData;
packetToSend->Data[1] = Downstream_HID_Mouse_Extract8BitValue(HID_Handle,
ReportXBitOffset,
ReportXBitLength);
packetToSend->Data[2] = Downstream_HID_Mouse_Extract8BitValue(HID_Handle,
ReportYBitOffset,
ReportYBitLength);
packetToSend->Data[3] = Downstream_HID_Mouse_Extract8BitValue(HID_Handle,
ReportWheelBitOffset,
ReportWheelBitLength);
}
uint8_t Downstream_HID_Mouse_Extract8BitValue(HID_HandleTypeDef* hidHandle,
uint8_t valueBitOffset,
uint8_t valueBitLength)
{
int32_t readData;
readData = *(uint32_t*)&(hidHandle->Data[(valueBitOffset / 8)]);
readData >>= (valueBitOffset % 8);
if (readData & (1 << (valueBitLength - 1))) //If value is negative...
{
readData |= ~((1 << valueBitLength) - 1); //...sign-extend to full width...
}
else
{
readData &= (1 << valueBitLength) - 1; //...else zero out unwanted bits
}
if (readData < INT8_MIN) readData = INT8_MIN; //Limit to 8-bit values
if (readData > INT8_MAX) readData = INT8_MAX;
return (int8_t)readData;
}
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