Yesterday while I was driving back to home my.

Yesterday while I was driving back to home my 2001 camry LE 2.2 engine and has 150k miles,
started making some knocking noise coming from the front if I accelerate or slow down and engine light turned on. Luckily I was just 2 blocks from my home so beofre I realised it has some trouble I managed to pulled it to my drive way, today morning I checked the oil with the stick- it is low.
my question is is it due to oil or something else, what engine oil shoul I pour in, and is it safe to drive down to repair shop if I pour oil for the diagnonsis. Cause I do not want to damage the engine further.