https://kernelnomicon.org/categories/driver/ Recent content in Driver on FreeBSD developer's notebook Hugo en-us Fri, 19 Feb 2010 06:22:00 +0000 https://kernelnomicon.org/posts/writing-freebsd-nic-driver/ Fri, 19 Feb 2010 06:22:00 +0000 https://kernelnomicon.org/posts/writing-freebsd-nic-driver/ <p>I&rsquo;ve been through writing NIC driver 2.5 times. 0.5 was porting ADM5120 switch driver by Ruslan Ermilov and Vsevolod Lobko from NetBSD. The usual routine for this kind of thing is &ldquo;take existing driver and rewrite it&rdquo;, e.g. copy selected parts or remove unnecessary ones. So I decided that it would be nice to skip &ldquo;remove&rdquo; part of procedure next time.</p> <p>All cards I had to deal with (&ldquo;both&rdquo; wouldn&rsquo;t be that impressive here) had similar design save for registers layout and some quirks. I believe that vast majority of NICs have the same design to some extent: there are circular RX/TX rings of more or less similar structure, interrupt status/mask register, media settings registers, you name it. Not a rocket science.</p>