Unsupported Reporting Services Functionality Error in Sharepoint 2013

Hi,

I am getting following error when i try to open powerview window from powerpivot gallery:

Unsupported Reporting Services Functionality

This SQL Server Reporting Services (SSRS) functionality is not supported. Use Central Administration to verify and fix one or more of the following issues:

• A report server URL is not configured. Use the SSRS Integration page to set it.
• The SSRS service application proxy is not configured. Use the SSRS service application pages to configure the proxy.
• The SSRS service application is not mapped to this web application. Use the SSRS service application pages to associate the SSRS service application proxy to the Application Proxy Group for this web application.

I am using SQL Server 2012 In integrated mode with Sharepoint 2013..

Please help..