Date: Tue, 8 Mar 2016 14:56:21 -0700 From: Brad Walker <bwalker@musings.com> To: Ian Lepore <ian@freebsd.org> Cc: Warner Losh <imp@bsdimp.com>, "freebsd-embedded@freebsd.org" <freebsd-embedded@freebsd.org> Subject: Re: ? about kernel size.. Message-ID: <CAPKZHbX8BXKC_=8PPvtasqE%2BRj96_mPQkqdRt=hqU6fazxpPfA@mail.gmail.com> In-Reply-To: <1457473674.1406.46.camel@freebsd.org> References: <CAPKZHbVyPji-bZwDzM77TN6qybjRcf%2BZe5r6WZmbG98LkhT-rg@mail.gmail.com> <CANCZdfriqr24Lh9ZuptaC0gEm6gAV6LN9XHcVAJtbyaBejEgNg@mail.gmail.com> <CAPKZHbW%2BG7WnSU__yeYBVPqs8MPmFm-5q_wM4sm9FxHhEEgPDg@mail.gmail.com> <1457473674.1406.46.camel@freebsd.org>
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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 <ian@freebsd.org> wrote: > On Tue, 2016-03-08 at 14:32 -0700, Brad Walker wrote: > > On Tue, Mar 8, 2016 at 11:42 AM, Warner Losh <imp@bsdimp.com> wrote: > > > > > > > > > > > On Tue, Mar 8, 2016 at 10:42 AM, Brad Walker <bwalker@musings.com> > > > 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 > >
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