Without mount picture it is virtually impossible to tel for which system was lens intended.

If you search in lens database you'll find OSAWA MC 135mm F/2.8 lens. If lens in database matches your copy in most parts (all except mount) you can narrow your search because according to database it was manufactured in following mounts (C/Y (contax/yashica), Canon FD, FDn, Konica AR, M42, Nikon F (FX, DX), Olympus OM, Pentax K, Minolta SR (MD, MC)) what makes majority of popular mounts for period when lens was produced. If lens was intended for Canon FD, FDn, Konica AR or Minolta SR (MD, MC) it is not worth a bother to convert to EOS EF mount (if you manage to find adapter for those three systems lens will be able to do only macro work or it'll have optical element eg. degradation optics).  

If you want more help pleas post mount picture.

Also you might find Hacking the Lens (or to hack or not to hack) article useful.

I also noticed that coating on front element (picture of front element in your post) looks funky (damaged) clean it and then decide if it is worth a trouble.

 

Best wishes

Radovan