From owner-freebsd-embedded@freebsd.org Tue Mar 8 21:56:23 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 43504AC7616 for ; Tue, 8 Mar 2016 21:56:23 +0000 (UTC) (envelope-from brad2000@gmail.com) Received: from mail-vk0-x22f.google.com (mail-vk0-x22f.google.com [IPv6:2607:f8b0:400c:c05::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id F0DD4915; Tue, 8 Mar 2016 21:56:22 +0000 (UTC) (envelope-from brad2000@gmail.com) Received: by mail-vk0-x22f.google.com with SMTP id e185so34174944vkb.1; Tue, 08 Mar 2016 13:56:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc; bh=FRAV7DWNSGy24zxgLeFZQV1hBfMJw6KEZVmkYgTPSEo=; b=fv0c69h8L56LzlnZd/UB23f3b32nMV052NAU+/VPkEv/TE4cqwzKoEBW8iGDd9N8Y9 Q63LZSjfB3N7tYD+Fz0FsK5Qxr8r4aTjwmlJra6fgrZDdFNWTFA8XPHFI1FdGshPykTs 1xGIkqif91ZxYGI1mO8u0VXPNJ4hZkLwOdcwxko7H18Iwi55kSKqJIo+C5Alnb+kZUNE N3QUeyXpOv2dC0B+gniXdCD4db0+99OAZJ6RnkkKFqxrJFenfqh5ahJP0fg0cgiX8y/J Ja3eAdTzMsr0v4c1YX0OrgZl55p97SG1XTlCtL/W19Y8Q9nEid0zZN2URs7mweac5Uns nj9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:cc; bh=FRAV7DWNSGy24zxgLeFZQV1hBfMJw6KEZVmkYgTPSEo=; b=fkkrtUTVkKJ5+xH8Tptw8mYGObHlKKZWvbSr1rMW2nnF/m3v9yg5geSZjz0JS+pB8a e0bDnBX4e9A/SGRkq9VcU6DqOVKNhDB3Mn/oDRvtraCj07tXr913lzdjLbF++pHbv/RK H3ZnnIQyiwnvV3bIGT53p7wnHIoVHpUvkKpGUL6FKtkeN0qmYJWHEHlxUgn+CfOH4SqY ianA0vF7uR+eafUC0AVgNyR4SFkDw4zMf/jfuLIAy8WEPghPJELqGOp9oDTsXt1eOMGr C7xfFqrcB3kdvvMteOsMFGeHgvzYtPhS7pewCtqaWCbzxdoO9Q6pCC/z8lheSbAuKIJW 0mIQ== X-Gm-Message-State: AD7BkJL9IDAzSsW+uobb7MkPPDScPz2T6avEWHDGyLBa82FszWaHdKrjzhDQxzKkfnWL8WnSCaR9OVcBlgMngQ== MIME-Version: 1.0 X-Received: by 10.31.52.73 with SMTP id b70mr24410401vka.16.1457474182019; Tue, 08 Mar 2016 13:56:22 -0800 (PST) Sender: brad2000@gmail.com Received: by 10.31.163.18 with HTTP; Tue, 8 Mar 2016 13:56:21 -0800 (PST) In-Reply-To: <1457473674.1406.46.camel@freebsd.org> References: <1457473674.1406.46.camel@freebsd.org> Date: Tue, 8 Mar 2016 14:56:21 -0700 X-Google-Sender-Auth: YOcjIsLcVXgsuXyTjIaZJMxbVJQ Message-ID: Subject: Re: ? about kernel size.. From: Brad Walker To: Ian Lepore Cc: Warner Losh , "freebsd-embedded@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 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 21:56:23 -0000 Correct. But, are you saying that no engineering has been done on this yet OR no amount of engineering could make it work? For example, I'm pretty well versed in the Solaris kernel stuff and there is really no amount of engineering that could make it work in a non-MMU environment.. I was thinking, at least in my mind, is that if Linux can do it certainly FreeBSD could if the work was done. Am I incorrect? -brad w. On Tue, Mar 8, 2016 at 2:47 PM, Ian Lepore wrote: > 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 > >