From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Mon, 12 Jan 2015 10:34:17 -0700 Subject: [U-Boot] [PATCH V2] add README.distro file In-Reply-To: <20150111181546.GM10826@bill-the-cat> References: <1419281200-6634-1-git-send-email-swarren@wwwdotorg.org> <1419758817.13595.33.camel@hellion.org.uk> <1420969535.11796.125.camel@hellion.org.uk> <54B2B8BB.1070005@wwwdotorg.org> <20150111181546.GM10826@bill-the-cat> Message-ID: <54B40599.6070009@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 01/11/2015 11:15 AM, Tom Rini wrote: > On Sun, Jan 11, 2015 at 10:54:03AM -0700, Stephen Warren wrote: >> On 01/11/2015 02:45 AM, Ian Campbell wrote: >>> On Sun, 2014-12-28 at 09:26 +0000, Ian Campbell wrote: >>>>> +boot_scripts: >>>>> + >>>>> + The name of U-Boot style boot.scr files that $bootcmd searches for. >>>>> + >>>>> + Example: boot.scr.uimg boot.scr >>>>> + >>>>> + (Typically we expect extlinux.conf to be used, but execution of boot.scr is >>>>> + maintained for backwards-compatibility.) >>>> >>>> I'm slightly concerned by the implied deprecation of the boot.scr method >>>> here, since at least Debian uses boot.scr exclusively and not the >>>> extlinux stuff. Will boot.scr be maintained going forward or are there >>>> plans to eventually remove it? >>> >>> Can someone confirm that there is no long term plan to drop boot.scr >>> support? >> >> extlinux.conf *is* the standard Linux boot process that >> config_distro_bootcmd.h enables. boot.scr is *not*. The whole point is >> to introduce a new simple standard that works the same everywhere (for >> Linux: across boards, across distros, across bootloaders). > > Well, the only problem I see with this statement is that, uh, do we have > buy-in from Debian? Well, there was some discussion about standard boot setups on the cross-distro mailing list. I believe someone from Debian is at least familiar with Dennis's proposal to use extlinux.conf as the standard. There was certainly no definitive agreement in those discussions though. That said, I don't think there's much choice but to standardize on /something/ other than boot.scr. boot.scr really isn't scalable for generic distros (as opposed to board-specific BSPs): * boot.scr works differently on different boards, since the set of environment variables and U-Boot commands/features available to the script are different. This leads to extremely complex boot.scr implementations that distros each have to maintain. I suppose we could fix this by standardizing the boot.scr execution environment; providing a consistent set of variables indicating where to load kernel/DTB/..., the board name (to auto-generate DTB filename), etc. However, standardizing this is more complex that standardizing on extlinux.conf and still doesn't solve: * boot.scr doesn't work across different bootloaders. There's no reason generic distros should know anything much about bootloaders, other than how to generate a config file so the bootloader knows which kernel/initrd/DTB binaries to load. * boot.scr must be generated (to boot.scr.uimg) using bootloader-specific tools, rather than extlinux.conf, grub.conf, ... all just need the generation of a text file.