From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Tue, 21 May 2019 15:53:11 -0400 Subject: [U-Boot] Making U-Boot smaller In-Reply-To: <1b28727d-efb0-cadb-4541-9383d4056808@denx.de> References: <1b28727d-efb0-cadb-4541-9383d4056808@denx.de> Message-ID: <20190521195311.GP22232@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, May 21, 2019 at 09:32:29PM +0200, Marek Vasut wrote: > On 5/21/19 6:56 PM, Jagan Teki wrote: > > On Tue, May 21, 2019 at 10:14 PM Simon Glass wrote: > >> > >> Hi, > >> > >> (moved from thread "U-Boot PXA support") > >> > >> We have of-platdata, which produces C data from the DT, for linking > >> into U-Boot. It saves libfdt and DT space. But we still have the DM > >> overhead. > >> > >> We have binman which can insert values into the binary after > >> link-time. This is barely used at present, only for accessing the > >> location of things in flash. > >> > >> Another thing is that every little tweak and feature adds a few bytes > >> and there are dozens of them in each release. It would be interesting > >> to build a board from 10 years ago (like PXA) and see where the growth > >> is. My bet is that we could add Kconfig options to disable extra > >> features (and enhancements of features) and make quite a difference. > >> > >> For DM, I think it would be interesting to revisit and compare against > >> the initial release, and see if some features could be made optional > >> in SPL. > >> > >> Finally I feel we could implement a single-device API for where > >> CONFIG_SPL_DM is not set. We could use the debug UART for serial, a > >> single instance of tiny MMC for MMC, etc. > > > > This is what I'm looking for quite sometime, a tiny MMC which would > > bypass the mmc stack and do the possible stuff in SPL, since we don't > > have any option to use full DM in SPL (specifically for Allwinner 64 > > SoC's). API that would atleast compatible with DM with small > > foot-print would help. > > It's been in mainline for a long time, MMC_TINY. Creator CI20 uses it. I want to start by saying I'm not criticizing MMC_TINY. But I think this highlights part of the problem of "lets do something that's not the normal framework". Developers come up with a one-off, do their best to make others know about it, and then a year later when someone else has a similar problem, they may or may not stumble into the alternate path fix. So, getting back to specifics, what would it take to do both: - Make MMC_TINY abstract enough sunxi or TI or ... could plug-in and use this for the "we just need MMC read, ROM probably already did enough init for us for this" - NOT blow up CI20 which I know is super tight on space. -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: not available URL: