From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Vasut Date: Fri, 11 Jul 2014 01:29:06 +0200 Subject: [U-Boot] [PATCH v2 08/29] dm: Allow drivers to be marked 'before relocation' In-Reply-To: <1404877099-7314-9-git-send-email-sjg@chromium.org> References: <1404877099-7314-1-git-send-email-sjg@chromium.org> <1404877099-7314-9-git-send-email-sjg@chromium.org> Message-ID: <201407110129.06857.marex@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wednesday, July 09, 2014 at 05:37:58 AM, Simon Glass wrote: > Driver model currently only operates after relocation is complete. In this > state U-Boot typically has a small amount of memory available. In adding > support for driver model prior to relocation we must try to use as little > memory as possible. > > In addition, on some machines the memory has not be inited and/or the CPU > is not running at full speed or the data cache is off. These can reduce > execution performance, so the less initialisation that is done before > relocation the better. > > An immediately-obvious improvement is to only initialise drivers which are > actually going to be used before relocation. On many boards the only such > driver is a serial UART, so this provides a very large potential benefit. > > Allow drivers to mark themselves as 'pre-reloc' which means that they will > be initialised prior to relocation. This can be done either with a driver > flag or with a 'dm,pre-reloc' device tree property. I think we should start marking those DT props something like 'u-boot,dm-pre- reloc' instead . The same way as Linux marks it's own linux-specific DT props. [...] Best regards, Marek Vasut