From owner-freebsd-embedded@freebsd.org Tue Mar 8 21:48:02 2016 Return-Path: Delivered-To: freebsd-embedded@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2A250A13FBD for ; Tue, 8 Mar 2016 21:48:02 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from pmta2.delivery6.ore.mailhop.org (pmta2.delivery6.ore.mailhop.org [54.200.129.228]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E4DE71F5 for ; Tue, 8 Mar 2016 21:48:01 +0000 (UTC) (envelope-from ian@freebsd.org) X-MHO-User: aa6fbe39-e577-11e5-8de6-958346fd02ba X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 73.34.117.227 X-Mail-Handler: DuoCircle Outbound SMTP Received: from ilsoft.org (unknown [73.34.117.227]) by outbound2.ore.mailhop.org (Halon Mail Gateway) with ESMTPSA; Tue, 8 Mar 2016 21:49:42 +0000 (UTC) Received: from rev (rev [172.22.42.240]) by ilsoft.org (8.15.2/8.14.9) with ESMTP id u28Lls8N004949; Tue, 8 Mar 2016 14:47:54 -0700 (MST) (envelope-from ian@freebsd.org) Message-ID: <1457473674.1406.46.camel@freebsd.org> Subject: Re: ? about kernel size.. From: Ian Lepore To: Brad Walker , Warner Losh Cc: "freebsd-embedded@freebsd.org" Date: Tue, 08 Mar 2016 14:47:54 -0700 In-Reply-To: References: Content-Type: text/plain; charset="us-ascii" X-Mailer: Evolution 3.16.5 FreeBSD GNOME Team Port Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-embedded@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Dedicated and Embedded Systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Mar 2016 21:48:02 -0000 On Tue, 2016-03-08 at 14:32 -0700, Brad Walker wrote: > On Tue, Mar 8, 2016 at 11:42 AM, Warner Losh wrote: > > > > > > > On Tue, Mar 8, 2016 at 10:42 AM, Brad Walker > > wrote: > > > > > I'm looking at working on a new project that will use the FreeBSD > > > kernel. > > > I > > > would attempt to embed the kernel on a very small NXP Kinetis > > > chip. I've > > > previously done this using a Linux kernel but also had DDR memory > > > attached > > > to the chip. This project would not have a DDR chip attached. > > > > > > So a couple of questions. 1 - What is the smallest size I could > > > configure > > > the FreeBSD kernel out of the box? Could I get the size to be > > > less than > > > 10MB, 5MB, 2MB, or etc.? > > > > > > > I've managed to get this down to about 2MB or a bit smaller. > > Compressed > > this can be a little smaller. It takes a fair amount of work, but > > it can be > > done. > > > > > > That's great.. Was this out of the box tuning? > > > > > > I did a little bit of research on the PicoBSD and NanoBSD but that > > still > > > seem to be targeted to a little bit bigger chip than I have > > > available. > > > > > > > How big a chip do you have? NanoBSD currently needs at least > > 64MB (and ideally 128MB) of storage. PicoBSD can be a bit smaller. > > > > I have 2MB on-chip flash and 512KB of SRAM. There is an external > flash that > will be attached. What I'm currently thinking is that I would like to > boot > into BusyBox verses multi-user.. > > One question that I'm curious about. All the work that I do on this, > or > you've done in the past, how does it get integrated into the mainline > build. Wait a sec here... NXP Kinetis is ARM Cortex-M, and that means no MMU, right? No MMU means no freebsd running on it. -- Ian