Enabling Bluetooth Serial Port Profile (SSP) for serial port emulator in Windows Embedded CE 6.0

Normally SSP is used by Hands Free Profile (HFP), Head set profile (HSP) and LAN Access Profile (LAP) in windows Embedded CE 6.0. However for some applications, SSP will be needed directly. Unfortunately there is no direct way of enabling the SSP in Windows CE ( No SYSGEN Variable).
SPP will be accessed through socket programming and COM port emulator. Based on the application requirement, Socket programming will be used for multiple port access and COM port emulator will be used for single port access. To enable the SSP, Application has to export the SSP through the service discovery protocol (SDP).
Exporting an service using SDP protocol is not a straight forward task. All the services are created as binary a record that has to be exported. All the services has mentioned as a unique ID and in the form of GUID. For SSP the GUID is 00001101-0000-1000-8000-00805f9b34fb. Please see the bt_sdp.h in _(WINCEROOT)\public\common\sdk\inc directory for more Bluetooth services. Microsoft has provided the sample applications , which explains the implementation of SSP over socket programming and serial port emulator.SSP has been exported in the socket programming example. Unfortunately port emulation code does not having the SSP export over SDP. Followings are the ways to create and export the SSP record.
1) Creating the service records dynamically through source code.
Creating a SDP record is done by using the Component Object Model programming. Writing the source code to create a service record is bit difficult for naive users. To facilitate the naïve users, Microsoft has given a sample application to create the source code for service as well as the binary record for the corresponding services. This source code is available in the _(WINCEROOT)\PUBLIC\COMMON\SDK\SAMPLES\BLUETOOTH\BTHNSCREATE directory. You can add this created source code to your application to invoke the service.
2) Using the sample socket programming over SSP.
_(WINCEROOT)\PUBLIC\COMMON\SDK\SAMPLES\BLUETOOTH\SSA is the sample implementation for the socket programming over SSP. It is having the SSP export code.
_(WINCEROOT)\PUBLIC\COMMON\SDK\SAMPLES\BLUETOOTH\SCA is the sample implementation for serial port emulator.
a) Create a new project, copy the SCA application code for serial port emulator implementation.
b) Add the following code as a glopal.
#define SDP_RECORD_SIZE 0x0000003f
#undef WSAGetLastError
#define WSAGetLastError() GetLastError()

BYTE rgbSdpRecord[SDP_RECORD_SIZE] = {
0x35, 0x3d, 0x09, 0x00, 0x01, 0x35, 0x11, 0x1c,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // service UUID goes here (+8)
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x09, 0x00, 0x04, 0x35, 0x0c, 0x35, 0x03, 0x19,
0x01, 0x00, 0x35, 0x05, 0x19, 0x00, 0x03, 0x08,
0x00, // server channel goes here (+40)
0x09, 0x00, 0x06, 0x35, 0x09, 0x09, 0x65,
0x6e, 0x09, 0x00, 0x6a, 0x09, 0x01, 0x00, 0x09,
0x01, 0x00, 0x25, 0x03, 0x53, 0x53, 0x41
};

This the Sdp record to be exported for the SSP. The size of the SSP GUID is 16 bytes and this will be added after 8 bytes of the SDP record. The Channel number will be added after 40 bytes of the SDP record.

c) Add the following code before calling the HANDLE h = RegisterBluetoothCOMPort (L"COM", index, &pp); function.

GUID serviceClassId;
ULONG recordHandle = 0;
WSADATA wsd;
if (WSAStartup (MAKEWORD(1,0), &wsd)) {
wprintf (L"Initialization of socket subsystem failed! Error = %d\n", WSAGetLastError ());
return 0;
}
GetGUID (_T("00001101-0000-1000-8000-00805f9b34fb"),&serviceClassId);
wprintf(L"Channel No=0x%x\n",pp.channel);
rgbSdpRecord[40] = (unsigned char)pp.channel;
GUID bigEndianGUID;
bigEndianGUID.Data1 = ((serviceClassId.Data1 << 24) & 0xff000000)
((serviceClassId.Data1 << 8) & 0x00ff0000)
((serviceClassId.Data1 >> 8) & 0x0000ff00)
((serviceClassId.Data1 >> 24) & 0x000000ff);
bigEndianGUID.Data2 = ((serviceClassId.Data2 << 8) & 0xff00)
((serviceClassId.Data2 >> 8) & 0x00ff);
bigEndianGUID.Data3 = ((serviceClassId.Data3 << 8) & 0xff00)
((serviceClassId.Data3 >> 8) & 0x00ff);
memcpy (bigEndianGUID.Data4, serviceClassId.Data4, sizeof(serviceClassId.Data4));
memcpy (rgbSdpRecord + 8, &bigEndianGUID, sizeof(bigEndianGUID));
struct {
BTHNS_SETBLOB b;
unsigned char uca[SDP_RECORD_SIZE];
} bigBlob;

ULONG ulSdpVersion = BTH_SDP_VERSION;
bigBlob.b.pRecordHandle = &recordHandle;
bigBlob.b.pSdpVersion = &ulSdpVersion;
bigBlob.b.fSecurity = 0;
bigBlob.b.fOptions = 0;
bigBlob.b.ulRecordLength = SDP_RECORD_SIZE;
memcpy(bigBlob.b.pRecord, rgbSdpRecord, SDP_RECORD_SIZE);
BLOB blob;
blob.cbSize = sizeof(BTHNS_SETBLOB) + SDP_RECORD_SIZE - 1;
blob.pBlobData = (PBYTE) &bigBlob;
WSAQUERYSET Service;
memset (&Service, 0, sizeof(Service));
Service.dwSize = sizeof(Service);
Service.lpBlob = &blob;
Service.dwNameSpace = NS_BTH;
int iRet = WSASetService(&Service,RNRSERVICE_REGISTER,0);
if (iRet != ERROR_SUCCESS) {
wprintf (L"WSASetService failes with status %d\n", WSAGetLastError ());
return 0;
}
pp.uuidService.Data1=serviceClassId.Data1;
pp.uuidService.Data2=serviceClassId.Data2;
pp.uuidService.Data3=serviceClassId.Data3;
memcpy(pp.uuidService.Data4,serviceClassId.Data4,sizeof(serviceClassId.Data4));
// HANDLE h = RegisterBluetoothCOMPort (L"COM", index, &pp);
HANDLE h = RegisterDevice (L"COM", index, L"btd.dll", (DWORD)&pp);
wprintf (L"handle = 0x%08x\n", (int)h);

if (h == NULL) {
wprintf (L"GetLastError = %d\n", GetLastError ());
return 0;
}
WCHAR szComPort[30];
wsprintf (szComPort, L"COM%d:", index);
HANDLE hCommPort = CreateFile (szComPort, GENERIC_READ GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
if (hCommPort == INVALID_HANDLE_VALUE) {
wprintf (L"Failed to open %s. Error = %d\n", szComPort, GetLastError ());
// DeregisterBluetoothCOMPort (h);
DeregisterDevice(h);
return 0;
}

To export the SSP, the only way you have to use the Winsock APIs. WSAStartup() and WSASetservice() are used for registering the SSP service. You can use RegisterDevice instead of RegisterBluetoothCOMPort provided you have to mention the DLL name as an argument. Please see the above code.

Thứ Năm, 8 tháng 9, 2011 10:34 Đọc tiếp >>

Work Around for data abort on L2 cache enabled PXA320 windows CE 6.0 platforms.

I have developed a BSP for PXA320 based platform running on windows embedded CE 6.0. I have taken the Zylonite windows CE 5.0 BSP. I faced an issue while enabling the PXA320 L2 cache. There are lots of data abort during the booting time from some drivers and application like explorer.exe. I track the call stack and I found the source code causing the data abort. OEMCacheRangeFlush () CACHE_SYNC_DISCARD case is causing the issue.
This case is used when the cache lines or the whole cache will be write-back and invalidate. Data Abort was occurring exactly when invalidating a range of cache lines. The invalidation operation for the whole cache or a range of the cache is decided based on the length and address. If length and address both are zero or the length is greater than the size of the cache, the whole cache will be flushed, otherwise only a particular set of cache lines will be flushed based on the address. Address passed as an argument is used to calculate the starting cache line to flush. L2 Cache is using physical address for cache operations. The cache flushing function is implemented in assembly language. It will convert the Virtual address to physical address through the page table entry. During this conversion sometime it is getting invalid page table data, which causes the data abort. I don’t know the reason for the invalid page table entry. But I have the workaround.
The work around is, use the same function used for flushing the entire cache instead of using the function implemented for flushing the lines.
Replace the function
XScaleFlushDCacheLinesL2((LPVOID) dwNormalizedAddress, dwNormalizedLength, ARMCacheInfo.dwL2DCacheLineSize);
With
XScaleFlushDCacheL2(DCACHE_LINES, ARMCacheInfo.dwL2DCacheLineSize, (DWORD) gpvCacheFlushBaseMemoryAddress);
This will stop the occurrence of data abort during the L2 cache flushing on OEMCacheRangeFlush().

Thứ Năm, 8 tháng 9, 2011 10:33 Đọc tiếp >>

Sharing Blocks of Memory between Kernel Mode Process and the User Mode Process in Windows Embedded CE 6.0

There are certain cases that we may need to share the same memory between kernel process and user process instead of copying the kernel memory data to user memory data or vice versa to increase the performance or process the data in a real time manner.
For Example, consider the scenario on the camera based application. A camera has sending the frames in 30 Frames per second. Approximately 33 ms is the interval between the 2 frames. The camera driver stores the captured data (640*480*8bits) within 5 ms for every frame and the remaining 28 ms has been left to process the data in the application for the required output. The driver has to store all the required frames as blocks of memory. It means if the application need 60 frames, the driver has to store the 60 Frames in the memory contiguously.
In this case, maintaining two large amount of memory in an embedded product will create scarcity of memory also this is not an efficient design. Unlike windows CE 5.0, directly accessing the kernel mode memory by the user process is restricted in windows CE 6.0 to avoid security vulnerability. However Windows Embedded CE 6.0 has introduced a new set of APIs that allows sharing the memory blocks between the kernel mode process and the user mode process in the secured manner.
VirtualAllocEX, VirtualCopyEx and VirtualFreeEX are newly introduced APIs in Windows CE 6.0 and allows you to share the memory between the kernel and the user mode processes. I can explain you the implementation through the sample stream driver and a user application. The virtual address space is allocated to the process id given as an argument to VirtualAllocEX (). In our example, virtual address space is allocated to user process area or application process area. You can print the address to find the address range. It should be less than 2 GB (user address space).
Allocating, sharing and freeing the memory address has been implemented through the IOCTL calls. The following source code explains the implementation.
DWORD SMD_IOControl (DWORD dwOpen, DWORD dwCode, PDWORD pIn, DWORD dwIn,
PDWORD pOut, DWORD dwOut, DWORD *pdwBytesWritten)
{
RETAILMSG(1, (TEXT("SMD_IOControl++ dwCode: 0x%x\r\n"),dwCode));
switch (dwCode)
{
case IOCTL_SMD_ALLOC_ADDRESS:
{
*pOut=(DWORD)GetVirtualAddress();
*pdwBytesWritten=4;
dwOut=4;
RETAILMSG (1, (TEXT("SMD_IOControl: Address=0x%x\r\n"), *pOut));
}
break;
case IOCTL_SMD_FREE_ADDRESS:
{
void* pvProcess=(void*)GetCallerVMProcessId();
VirtualFreeEx(pvProcess,(PVOID)((ULONG)gUserAddr & ~(ULONG)(PAGE_SIZE - 1)), 0,MEM_RELEASE);
gUserAddr=NULL;
}
break;
case IOCTL_SMD_FILL_ADDRESS:
{
char* Temp= (char*)((char*)gUserAddr+0x1F00000);
NKDbgPrintfW(L"Address=0x%x\r\n",Temp);
Strcpy(Temp," Hello World");
NKDbgPrintfW(L"Written value =%s\r\n",Temp);
}
break;

default:
{
DEBUGMSG (1, (TEXT("SMD_IOControl: unknown code %x\r\n"), dwCode));
}
return FALSE;
}

RETAILMSG(1, (TEXT("SMD_IOControl Finished--\r\n")));
return TRUE;

}

LPVOID GetVirtualAddress()
{
DWORD sDevPhysAddr = 0x81F00000;
DWORD dwSize = 0x02000000;
LPVOID lpUserAddr;
ULONG SourceSize;
ULONGLONG SourcePhys;
void* pvProcess=(void*)GetCallerVMProcessId();
SourcePhys = sDevPhysAddr & ~(PAGE_SIZE - 1);
SourceSize = dwSize + (sDevPhysAddr & (PAGE_SIZE - 1));
lpUserAddr = VirtualAllocEx(pvProcess, 0, SourceSize, MEM_RESERVE,PAGE_NOACCESS);
if (lpUserAddr == NULL) {
return NULL;
}
if (!VirtualCopyEx(pvProcess, lpUserAddr, GetCurrentProcess(), (PVOID)
SourcePhys, SourceSize,
PAGE_READWRITE PAGE_NOCACHE)) {
return NULL;
}
NKDbgPrintfW(L"Before round up lpUserAddr=0x%x\r\n",lpUserAddr);
lpUserAddr=(LPVOID)((ULONG)lpUserAddr+(sDevPhysAddr & (PAGE_SIZE - 1)));
gUserAddr=lpUserAddr;
NKDbgPrintfW(L"After round up gUserAddr=0x%x\r\n",gUserAddr);
return lpUserAddr;
}

IOCTL_SMD_ALLOC_ADDRESS: This Ioctl allocates blocks of memory and return the starting address of the allocated area to the user mode process (Application).
IOCTL_SMD_FREE_ADDRESS: This IOCtl frees the allocated shared memory area using VirtualFreeEX ().
IOCTL_SMD_FILL_ADDRESS: Just fill the data at the end of the large block of memory. These data can be printed by the application for the proof of concept of shared memory implementation.
GetVirtualAddress (): It allocates 32 MB of large memory, which can be shared by the kernel mode process and the user mode process. This function calls the GetCallerVMProcessId () to get the caller process id given as an argument to VirtualAllocEx () and VirtualCopyEX (). The caller process id is the application process id or user mode process id in our case. VirtualAllocEx takes the caller process id and the current process id as an argument and allocates the shared memory. Usage of the VirtualAllocEx and VirtualCopyEx are very similar to the VirtualAlloc and VirtualCopy.
The following is the sample application access the memory allocated by the sample memory driver.
HANDLE SMDDrv;
// Open the sample memory driver
SMDDrv=CreateFile(L"SMD1:", //file name to be opened
GENERIC_WRITEGENERIC_READ, //openign he fiel in read mode
0, //no share mode
NULL, //default security
OPEN_EXISTING, //opening an existing file
0, //non overlapped mode
NULL //no any template file
);
if(SMDDrv==INVALID_HANDLE_VALUE)
{
printf(":SMD open failed\r\n");
}
else
{
printf(":SMD open success\r\n");
}
//Get the allocated shared pointer
DeviceIoControl(SMDDrv,IOCTL_SMD_ALLOC_ADDRESS,NULL,0,&Address,sizeof(DWORD),&BytesWritten,NULL);
char* Data=(char*)Address;
printf("Address:0x%x",Data);
//Request the driver to fill the data
DeviceIoControl(SMDDrv,IOCTL_SMD_FILL_ADDRESS,NULL,0,NULL,0,NULL,NULL);
// Move the pointer to the filled data area
Data+=0x1F00000;
//Just print the data for proof of concept
printf("Data:%s",Data);
// Free the memory
DeviceIoControl(SMDDrv,IOCTL_SMD_FREE_ADDRESS,NULL,0,NULL,0,NULL,NULL);
//Close the driver handle
CloseHandle(SMDDrv);
I have given the simple application that opens the driver, get the large memory pointer, move to the data area filled by the driver, print the data and close the driver.
Hope this blog is useful for architects and developers, who are all in need of sharing the large blocks of memory between the user and kernel mode processes.

Thứ Năm, 8 tháng 9, 2011 10:33 Đọc tiếp >>

Make it work .NET Compact Framework on PXA320 based Windows Embedded CE 6.0 Platform NET

I have developed a BSP for PXA320 based platform running on windows embedded CE 6.0 R2. I have taken the Zylonite windows CE 5.0 BSP. I faced a strange issue while running the Dot Net Compact framework based application. The application failed to run even though the necessary components have been included for the Dot Net Compact framework.
I tried to run the cgacutil.exe to get the version of the .net framework. I got “Registration Failed” message in the console. Same issue I faced when I installed the .Net Framework through the cab installer. I tried the same project file (.pbxml) with other platform. I found the .net framework was working.
So the issue should be related to BSP. During the installation of the .NET Compact framework, the IOCTL_HAL_GET_DEVICE_INFO is called through the kernelIOcontrol to get the device information for registration. This IOCTL will give set of system parameter information through some SPI cases. One of the cases is SPI_GETPLATFORMNAME. This will give the platform name and it is used during the .NET compact framework GAC implementation. This case is missing in my BSP, since I have used the Zylonite windows CE 5.0 BSP. Because of this .NET Compact Framework is not working.
Workaround 1:
a) Add the global declarations
const WCHAR HALPlatNameStr[] = L"XXXPlatform" ;
const DWORD dwHALPlatNameStrLen = 9;
b) Add the following code in the src\oal\oallib\ioctl.c OALGetDeviceInfo() function.
case SPI_GETPLATFORMNAME:
len = (dwHALPlatNameStrLen+1)*sizeof(WCHAR);
if (lpBytesReturned)
*lpBytesReturned = len;
if (nOutBufSize >= len && lpOutBuf)
{
memcpy(lpOutBuf,HALPlatNameStr,len);
retval = TRUE;
} else
NKSetLastError(ERROR_INSUFFICIENT_BUFFER);
break;

(OR)
Workaround 2:
Do the following changes in src\inc\ioctl_tab.h file.
{ IOCTL_HAL_GET_DEVICE_INFO, 0, OALIoCtlHalGetDeviceInfo },
//{ IOCTL_HAL_GET_DEVICE_INFO, 0, OALGetDeviceInfo },
Use the common OAL IOCTL function OALIoCtlHalGetDeviceInfo() instead of OALGetDeviceInfo(). The OALIoCtlHalGetDeviceInfo() will finally use the g_oalIoCtlPlatformType value implemented in the ioctl.c file.

Thứ Năm, 8 tháng 9, 2011 10:32 Đọc tiếp >>

How to open a Windows CE stream device with the Index number greater than ten

Many Windows CE devices contain multiple peripherals. Some peripherals will be accessed through windows CE native drivers and the remaining peripherals will be accessed through stream drivers. A typical example of native driver is display driver and a typical example of stream driver is serial port. Stream driver is a simple, also powerful architecture and it is extremely flexible to develop a driver for any kind of devices. Serial port driver, bus drivers and custom device drivers are the typical examples for the stream driver.
We can take a serial port driver as an example to explain this blog. Devices like POS terminals need several serial ports to connect the peripherals like GPS, GSM Modem, IR devices, Magnetic card readers etc. In some cases, we need virtual serial port to access devices. We assume a POS terminal contains more than ten serial ports. This blogs explains you – how to access the serial port with the Index number greater than 10.
Opening a serial port device with an index number less than 10
Normally a combination of three letter prefix with the index number alone used to open the serial port driver. For example “COM3” is the name space used to open the serial port with the index 3. Following code snippet explains you to open the serial port with the index 3.
HANDLE hPort;
hPort = CreateFile(TEXT("COM3:"), GENERIC_READ GENERIC_WRITE, 0,NULL, OPEN_EXISTING, 0, NULL);
This method supports to open a serial port with the index less than 10. Index1-9 represents the first nine serial ports and index 0 represents the 10th serial port. This method is called as legacy naming convention.
Opening a serial port device with an index number greater than 10
We need to add a device string in front of the above mentioned notation to open a serial port with the index greater than 10. Following code snippet explains you to open the serial port with the index 20.
HANDLE hport;
hPort = CreateFile(TEXT("\$device\COM20"), GENERIC_READ GENERIC_WRITE, 0,NULL, OPEN_EXISTING, 0, NULL);
This method supports to open a serial port with any index from 0. This means, we can also open the index 3 with this method.

Thứ Năm, 8 tháng 9, 2011 10:31 Đọc tiếp >>

Kernel.org hacked – how to get Android repo?

As you may already know, kernel.org site which hosts the Android git repository has been hacked. Because of this we can’t obtain the Android source code from its servers. All attempts to do so ultimately fail with the similar response:

[root@localhost WORKING_DIRECTORY]# repo sync
android.git.kernel.org[0: 130.239.17.13]: errno=Connection refused
android.git.kernel.org[0: 199.6.1.173]: errno=Connection refused
android.git.kernel.org[0: 2001:6b0:e:4017:1972:112:1:0]: errno=Network is unreachable
android.git.kernel.org[0: 2001:500:60:10:1972:112:1:0]: errno=Network is unreachable
fatal: unable to connect a socket (Network is unreachable)
error: Cannot fetch platform/bionic

I will describe another way to get the Android source codes if you hadn’t already cloned it’s repo before kernel.org servers went down.

Prepare the environment

First, you need to download “repo” script from kernel.org my blog (please, use double quotes around the URL address):

curl "http://php.webtutor.pl/en/wp-content/uploads/2011/09/repo" > ~/bin/repo
chmod a+x ~/bin/repo
PATH=~/bin:$PATH

Download the Android repository

Now, you can safely download the repository, like so:

mkdir WORKING_DIRECTORY
cd WORKING_DIRECTORY
repo init -u git://codeaurora.org/platform/manifest.git -b gingerbread
repo sync

and start the development…

Thứ Tư, 7 tháng 9, 2011 23:53 Đọc tiếp >>

Download Logitech Webcam Driver to Have your Camera Work Well

You’re video chat is just an hour from now and all of a sudden your webcam has started working in a strange manner. It isn’t displaying anything properly, or perhaps the images are getting crooked like your reflection in moving water, or it’s got too dark or too bright to understand what exactly it is. Do you think your Logitech webcam has got damaged all of a sudden?

But there are chances that there isn’t anything wrong with the camera as such and it is actually your Logitech webcam driver that has developed the actual problem. Now since your conference is in the next one hour, even if you’re going to approach a service engineer, your camera will hardly be mended up in that less a time. But if the trouble comes out to be with the driver, you can correct it within no time.

So, why don’t you check out your Logitech webcam driver before picking up the phone and calling the service station? And interestingly, it is an easy to do thing to check out the driver and equally easy to get it replaced.

Now, if you’re wondering what is the role of the driver in the working of the various devices on your laptop, you first need to know what exactly it is and how does it work. Any device on your system needs a particular driver for working properly. It basically happens to be a small piece of software that works like a bridge between its corresponding device and your system and when it gets missing or goes broken, the link between the device and the system also gets broken.

And when this happens, the particular device stops understanding any of your commands. Thus, if your Logitech webcam driver has got damaged or removed, your webcam will simply not understand any of your commands and it won’t be working properly.

You just need to check your system, whether the driver is present or not. One out of three most probable things might have happened; first, the driver can have got outdated, in this case you’ll just need a quick update, second, it can have got damaged or deleted. Now if it has got damaged, you’ll have to delete the damaged driver and reinstall it a fresh, and if it has got deleted, you’ll simply have to get it installed, that’s all. Third, this is though a queer thing to happen but does happen once in a while that you’ve used a wrong Logitech webcam driver on your system. 

Simply suppose, you’re using a Mac but you have downloaded the driver for Windows, this will surely not work well at any cost.

Now what? Nothing, simply get online and download the driver and reinstall it. You’ll just have to land up on a page offering right Logitech webcam driver, i.e. especially meant for your OS, the make and model of your laptop, etc. for the download. Once downloaded, install it quickly and check out whether the camera is doing fine now, if the trouble was with the driver, it will surely work well now.

Thứ Hai, 5 tháng 9, 2011 23:39 Đọc tiếp >>