The Pallava script or Pallava Grantha, is a Brahmic script, named after the Pallava dynasty of South India, attested since the 4th century AD. In India, Pallava script evolved into the Tamil  and Grantha script . 
The Cham script is a descendant of the Brahmi script of India. Cham was one of the first scripts to develop from a script called the Pallava script some time around 200 CE. It came to Southeast Asia as part of the expansion of Hinduism and Buddhism.