How to get device path and mount path using usbdi callbacks? - usb

I am in the progress of implementing a service which will detect usb plugin/removal using usbdi callback functions. Callback function has a parameter "usbd_device_instance_t * usbInstance" from which i can get device vendor id,product id and the device class information. But how do i get a mount point in case of a mass storage device and a device path in case of a HID device?

In QNX 6.6 and 7.0, usblauncher writes a map of detected devices, launched drivers, and their arguments such as mount point to the PPS tree. The USB Launcher Service reference manual has complete documentation on the location and formatting of these entries. You could scan them to find out what high level details you need.
That said, the usblauncher script engine also provides a place where you could add custom on-connect commands directly; that might be easier than writing a new service.

Related

How does an O.S. or a high level abstraction layer gain knowledge of the hardware using the device driver?

When reading about hardware/device independence this statement from wikipedia (http://en.wikipedia.org/wiki/Device_independence#Desktop_computing) states that:
The application software does not need to know anything about the hardware on which it was to be used. Instead it discovers the capabilities of the hardware through the standardized abstraction layer, and then use abstracted commands to control the hardware.
I wanted to know about the lower level interaction between the BIOS routine/device driver/HAL/OS and the device controller about discovering the hardware capabilities.
Kindly help me out to understand the communication between these entities that takes place which helps in hardware independence.
Hardware devices, normally, connect to the main controller through a standard bus of some kind.
For example - PCI, PEX, USB.
Each connected device on the bus will be allocated with a device #, bus #, function #, etc, by the bus controller.
Modern bus contollers either provide the main controller with the ability to perform a scan, or send an event when a device is hot plugged into the bus.
Per each discovered device, it is possible, using the bus controller standard commands (such as read/write registers of a device, by device ID, bus number, etc), to interrogate the device for details such as:
Manufacturer ID
Device ID
Class (controller / networking device / Human interface / imaging device / and so on)
Per bus type, all these details must be available in the same way for every connected HW device, thus enabling the OS to use an abstraction layer.
Once a device has been discovered and identified, the OS will call all the specific bus registered device drivers' probe function, which use the details mentioned above to decide if can handle it.
When a device driver probe succeeds, an instance of the driver is allocated and can be used directly by the application that needs to access the HW.
For example:
USB PC CAM connects to USB port. An event is sent to the main CPU by the USB bus controller. The CPU will use the standard USB bus controller functions to learn the manufacturer & device ID/s, device class, functions, etc, and will call all the USB registered device drivers probe functions.
If an appropriate device driver is installed (registered), it will successfully create an instance of the device and a video application (such as skype) can use it directly, through DLLs supplied by the driver SW.
Hope this helps.

How to create a USB STACK using win32 programming

I am doing my Project using win 32 programming.I am just learning about win32 programming and able to create an UI.I want to communicate with an USB Device with that UI.SO,How can i go for that?Is there any predefined functions will be there are we need to create the function for communicating with the OS and get the devices List and got the details about them.
My purpose is to ,
1.Creating an UI that tells about the Basic information about the device.
2.For that first of all i want to communicate with the OS for device attachment and find the drivers for that.That will lead to get the information about the device and communicate with the device using that UI.
So,can anyone help me about this?How can i achieve this or approach this?
Assuming your USB Device enumerates as a vendor specific device and not a class that has a preloaded driver WinUSB would be perfect for your case. If it is loading a class driver such as HID or some other class you will need to look up the API for that type of device on MSDN.

USB device design for an embedded MCU

I am working on a product with an LPC1788 which needs the following USB features:
Firmware download (from host PC to device, not through a USB
key).
File upload (from device to host).
Ideally we'd also be able to get some information from the device like serial number etc.
The device should only work with a custom Windows application, so simply using a mass-storage device as-is will not do. There are quite a lot of data to upload (200MB +), so using USB bulk transfers seem necessary to me.
What is the best way to approach this? I imagine I would need to create some sort of USB composite device(?). However, I was hoping to use nxpUSBlib or winUSB so I don't have to go through the Windows driver validation process.... What are my options? Perhaps there some way to make the mass-storage device invisible for Windows?
Thanks!
Dirk
I think you'll definitely want to go with a vendor specific bulk device and you can easily use WinUSB for all of this. This should be sufficient for everything you've specified here.
For your firmware loader I'd recommend looking at the DFU (device firmware update) specification. You'll probably want make some command for your device that when sent will cause it to reenumerate itself in to DFU mode for update (rather than a composite device that is always exposed - this restricts the issue of the other interface being in use while you're flashing your device). Then you can flash it and reset it so it will reenumerate as your vendor specific bulk device again.
I wouldn't recommend mucking with mass storage, from your requirements it will be better to implement your own protocol and create some application or DLL that consumes the WinUSB API to communicate with your device, including the firmware update.

Access SmartCards from Windows 8 Store App (WinRT)

In a Windows 8 Store App I would like to read Data from a SmartCard. After installing the SmartCard reader (USB Device) I can read its device path and connection state via the Windows.Devices.Enumeration namespace. Even the device interface id is retrievable (50dd5230-ba8a-11d1-bf5d-0000f805f530) and I put this as a required capability in the App's manifest file.
For the interaction with the device I use a C++ Component calling the CreateDeviceAccessInstance Method. But this call always results in an ACCESS_DENIED exception.
Further research taught me, that interacting with a custom hardware device (everything that is not a printer, microphone, mouse, ...) would need several adjustments in the device driver published to the windows 8 driver store.
I'd be glad to do so, but I am no IHV and would like to use the generic driver and the generic interface.
Could anyone give me a hint how to proceed from here and use the generic interface for USB SmartCard devices?
This is not a real answer, but I have the same problem and I have spent quite some time looking for the hard-to-find bits of information on this subject around the internet, and I'd like to share my results.
Windows 8.1 has some specific APIs for (virtual) SmartCards (API reference, sample), but it seems like they can only be used for authentication and there is no way to send APDU commands to a card at the moment (see this comment by Himanshu Soni). I guess one could use the new USB APIs to talk to the reader directly, but then you'd have to implement the whole protocol yourself.

USB HID device detection

I am trying to access an USB HID device under Ubuntu(kernel-3.0). I want to write a program which could notify me whenever an USB device is attached to the bus i.e is there any event generated whenever an USB device is plugged in which I can monitor. I have looked into DBus and HAL without any success. But I don't want linux to load its current modules(USBHID and HID) when the device is plugged in. I also want to ask if the mentioned modules are also the device drivers used for HID devices.
My sole purpose is to run a script whenever an USB device is plugged into the bus which will indirectly call the above mentioned modules.
I am writing my code in C. I am quite new to linux. So it would be of great help if anyone could point me in the right direction.
Thanks..
The UDisks deamon will send the D-Bus signal "DeviceAdded" when a USB drive is inserted, and probably another "DeviceAdded" for each partition on the drive. If you have automount you would also get a "DeviceChanged" signal when the partition(s) are mounted. You can then query the UDisks interface, as well as individual devices about their properties, for example. You can find more info on the UDisks interface here: http://hal.freedesktop.org/docs/udisks/UDisks.html
One way to get more familiar with what goes on with block devices (or whatever) on D-Bus, is to install and use D-Feet to inspect the bus. UDisks appear on the System bus. You can see what is there and inspect the properties for individual devices as well as the UDisks interface itself.
Another way, which would also allow you to see what signals are transmitted on the bus, is to run dbus-monitor from the command line.