I am a shareholder of a corp where I work as an employee and control > 40% of corp's voting shares. I am enrolled in CRA EI program. How do I calculate my EI premium?

If you are an employee of the corporation, then the corporation (your employer) should issue you a T4 slip that shows your income and the EI contributions (both yours and the corporation's). Your EI contributions would only be calculated on your tax return if you were self-employed (non incorporated business).