functionality of an Integrated Circuit?

This is the board of Cisco IP phone. I don't know what this chip is and its usage in the IP phone.

Which package?

Unfortunately, I don't have access to the main board now. but with attention to below image and the size of another chip on the board that was marked with green circle, may be guess about the length of our chip inside the red circle.

 Thanks

Is it possible this component be a counterfeit component?

Counterfeiters go to great lengths to use a well-known "standard" label so that they can sell the chip as much as possible.

What you have is likely to be the opposite: a genuine chip where Cisco paid TI to keep the information secret. (But they did not pay enough for TI to omit the logo; possibly it's a custom chip.)