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Merge pull request #5 from dioannidis/windows_os_descriptor
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Use windows's winusb driver
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@nerdralph
nerdralph authored Mar 23, 2021
2 parents 28b2db7 + a2ab97e commit 3206fd4
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Showing 3 changed files with 421 additions and 11 deletions.
171 changes: 162 additions & 9 deletions firmware/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,8 +35,155 @@ static unsigned int prog_pagesize;
static uchar prog_blockflags;
static uchar prog_pagecounter;


/* USBasp default winusb driver for Windows.
Based on the hard work by Marius Greuel @mariusgreuel ( https://github.com/mariusgreuel/USBasp ).
This is a non intrusive version, using an unaltered V-USB with no changes in it's usbdrv code.
To avoid using driver installation (Zadig, libusb) on Windows and use by default
the winusb default driver for USBasp, we need to use OS feature descriptors.
All USB 2.0 devices, when they are enumerated for the first time, Windows asks if
there is an OS feature descriptor by sending a specific standard GET_DESCRIPTOR request
with the format :
--------------------------------------------------------------------------------------------------
| bmRequestType | bRequest | wValue | wIndex | wLength | Data |
--------------------------------------------------------------------------------------------------
| 1000 0000B | GET_DESCRIPTOR | 0x03EE | 0x0000 | 0x12 | Returned string |
--------------------------------------------------------------------------------------------------
It asks if there is a specific string descriptor at index 0xEE. Because this string
descriptor request, is not by default handled by the V-USB, we change the USB_CFG_DESCR_PROPS_UNKNOWN
to be dynamic (USB_PROP_IS_DYNAMIC). This effectively tell the V-USB that for every
unknown string index request to call the usbFunctionDescriptor function.
usbFunctionDescriptor function returns an OS string descriptor using the version 1.00 format
which has a fixed length of 18 bytes, with a structure as shown in the following table :
--------------------------------------------------------------------------
| Length | Type | Signature | MS Vendor Code | Pad |
--------------------------------------------------------------------------
| 0x12 | 0x03 | MSFT100 | unsigned byte | 0x00 |
--------------------------------------------------------------------------
Length: An unsigned byte and MUST be set to 0x12.
Type: An unsigned byte and MUST be set to 0x03.
Signature: A Unicode string and MUST be set to "MSFT100".
MS Vendor Code: An unsigned byte, it will be used to retrieve associated feature descriptors.
Pad: An unsigned byte and MUST be set to 0x00.
The Signature field contains a Unicode character array that identifies the descriptor as an
OS string descriptor and includes the version number. For version 1.00, this array must be set
to "MSFT100" (0x4D00 0x5300 0x4600 0x5400 0x3100 0x3000 0x3000).
The MS VendorCode field is used to retrieve the associated feature descriptors. This code is
used as Request field in TS_URB_CONTROL_VENDOR_OR_CLASS_REQUEST section 2.2.9.12.
In usbFunctionSetup we handle the feature request associated to MS Vendor Code we replied earlier
and send an Extended Compat ID with the information that we want Windows to load the winusb default driver.
For More information see
https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors
https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-rdpeusb/c2f351f9-84d2-4a1b-9fe3-a6ca195f84d0
!!! Notice !!!
"After the operating system requests a Microsoft OS String Descriptor from a device, it creates the following registry key:
HLKM\SYSTEM\CurrentControlSet\Control\UsbFlags\vvvvpppprrrrr
The operating system creates a registry entry, named osvc, under this registry key that indicates
whether the device supports Microsoft OS Descriptors. If the device does not provide a valid response
the first time that the operating system queries it for a Microsoft OS String Descriptor,
the operating system will make no further requests for that descriptor."
If your firmware doesn't work please delete the registry key as stated above to retrigger a query from Windows.
i.e. if your firmware has a device version of 0x07, 0x01 then there will be a registry key with the name :
Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbflags\16C005DC0107
*/


/* For Windows OS Descriptors we need to report that we support USB 2.0 */

PROGMEM const char usbDescriptorDevice[18] = { /* USB device descriptor */
18, /* sizeof(usbDescriptorDevice): length of descriptor in bytes */
USBDESCR_DEVICE, /* descriptor type */
0x00, 0x02, /* USB version supported */
USB_CFG_DEVICE_CLASS,
USB_CFG_DEVICE_SUBCLASS,
0, /* protocol */
8, /* max packet size */
/* the following two casts affect the first byte of the constant only, but
* that's sufficient to avoid a warning with the default values.
*/
(char)USB_CFG_VENDOR_ID,/* 2 bytes */
(char)USB_CFG_DEVICE_ID,/* 2 bytes */
USB_CFG_DEVICE_VERSION, /* 2 bytes */
1, /*USB_CFG_DESCR_PROPS_STRING_VENDOR != 0 ? 1 : 0,*/ /* manufacturer string index */
2, /*USB_CFG_DESCR_PROPS_STRING_PRODUCT != 0 ? 2 : 0, */ /* product string index */
3, /* USB_CFG_DESCR_PROPS_STRING_SERIAL_NUMBER != 0 ? 3 : 0, */ /* serial number string index */
1, /* number of configurations */
};

/* OS Extended Compat ID feature descriptor */

PROGMEM const char OS_EXTENDED_COMPAT_ID[37] = {
/* Header */
0x25, /* OS Extended Compat ID feature descriptor length */
0x01, 0x00, /* OS Extended Compat ID version */
0x00, 0x04, /* Index */
0x01, /* Configurations count */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Reserved */
/* Configuration */
0x00, /* First Interface Number */
0x01, /* Reserved */
'W','I','N','U','S','B', 0x00, 0x00, /* Windows string Compatible ID */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* Windows string SubCompatible ID */
0x00, 0x00, 0x00, 0x00, 0x00, 0x00 /* Reserved */
};

#define MS_VENDOR_CODE 0x5D
PROGMEM const char OS_STRING_DESCRIPTOR[18] = {
0x12, /* Length: An unsigned byte and MUST be set to 0x12. */
/* https://docs.microsoft.com/en-us/windows-hardware/drivers/network/mb-interface-model-supplement */
0x03, /* Type: An unsigned byte and MUST be set to 0x03. */
'M',0,'S',0,'F',0,'T',0,'1',0,'0',0,'0',0, /* Signature: A Unicode string and MUST be set to "MSFT100". */
MS_VENDOR_CODE, /* MS Vendor Code: An unsigned byte,
it will be used to retrieve associated feature descriptors. */
0x00 /* Pad: An unsigned byte and MUST be set to 0x00. */
};

usbMsgLen_t usbFunctionDescriptor(struct usbRequest *rq) {

// DBG1(0xEE, &rq->wValue.bytes[0], 2);

/* string (3) request at index 0xEE, is an OS string descriptor request */
if ((rq->wValue.bytes[1] == 3) && (rq->wValue.bytes[0] == 0xEE)) {

usbMsgPtr = (usbMsgPtr_t)&OS_STRING_DESCRIPTOR;

return sizeof(OS_STRING_DESCRIPTOR);

};

return 0;

};

uchar usbFunctionSetup(uchar data[8]) {

const usbRequest_t* request = (const usbRequest_t*)data;

uchar len = 0;

if (data[1] == USBASP_FUNC_CONNECT) {
Expand Down Expand Up @@ -178,15 +325,21 @@ uchar usbFunctionSetup(uchar data[8]) {
prog_state = PROG_STATE_TPI_WRITE;
len = 0xff; /* multiple out */

} else if (data[1] == USBASP_FUNC_GETCAPABILITIES) {
replyBuffer[0] = USBASP_CAP_0_TPI;
replyBuffer[1] = 0;
replyBuffer[2] = 0;
replyBuffer[3] = 0;
len = 4;
}

usbMsgPtr = replyBuffer;
/* Handle the OS feature request associated with the MS Vendor Code
we replied earlier in the OS String Descriptor request. See usbFunctionDescriptor. */
} else if (request->bRequest == MS_VENDOR_CODE) {
if (request->wIndex.word == 0x0004)
{
/* Send the Extended Compat ID OS feature descriptor,
requesting to load the default winusb driver for us */
usbMsgPtr = (usbMsgPtr_t)&OS_EXTENDED_COMPAT_ID;
return sizeof(OS_EXTENDED_COMPAT_ID);
}

return 0;
}

usbMsgPtr = replyBuffer;

return len;
}
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