i am trying to port freeRTOS on zedboard . i downloaded the FreeRTOSV8.2.1 from the website but from there on i don't know what to do next. i tried searching a lot but i couldn't find a source that tells me how to do it from scratch.
The demo is somewhat separate from the hardware on which it is running. If you stick to the blinky demo you will probably find the only thing you need to change is the port number used to toggle an LED.
The Xilinx tools keep the hardware definition and BSP separate from the application. So you will need to create a hardware definition project for your hardware (I'm sure you will be able to download one, if indeed, there is not one already built into the SDK), then create a BSP for your project (using the File->new->bsp menu in the SDK), then import the FreeRTOS project and set it to use the BSP you just created.
Alternatively, I think in the SDK you can simply use the File->New->Application project menu option, then you will be presented with some pre-configured hardware platforms, and you may find yours is listed.
These are Xilinx tools questions though, not FreeRTOS questions.
I attached a screen-dump called "xilinx_project.png", hope it's helpful.
The Xilinx projects in Eclipse are a bit different from what you might be used to. To run a program, you need 3 sub-projects:
BSP : these are source files created by and maintained by Xilinx
Right-click to find a button call "Re-generate BSP sources"
MicroZedhwplatform, containing files like ps7_init.* and system.xml.
(You can download this sub-project)
RTOSDemo or your own source tree.
To run the project you will have to add a debug configuration.
I showed mine in the attachment.
It took me a lot of time to find out that you must use an initialisation file (ps7init.tcl), and use the options shown ("Reset Entire System", and "Run ps7init").
Under Application you will choose something like "Debug/RTOSDemo.elf".
Also check the project references, RTOSDemo refers to the 2 other projects that you use: "MicroZedhwplatform" and the BSP project.