On Thu, 9 Sep 2010 09:26:39 +0200 Wolfgang Denk <w...@denx.de> wrote:
> Dear Scott Wood, > > In message <20100908160001.374ff...@schlenkerla.am.freescale.net> you wrote: > > > > > In message <20100908153455.527fc...@schlenkerla.am.freescale.net> you > > > wrote: > > > > > > > > > > > Why not use uImage like we do with other architectures? > > > > > > > > > > > > Whereas they'd say why can't U-Boot accept a simple binary, and just > > > > > > run it in place without copying, like any other loader can? > > > > > > > > > > U-Boot can do that. Use the "go" command. > > > > > > > > Will things like the device tree get passed just as if the bootm > > > > command were used? > > > > > > No, of course not. You asked about starting "a simple binary". > > > > > > I warned you that you might lose some nice features... > > > > What does passing a device tree have to do with the image format? > > Nothing. Then why does u-boot only support certain calling conventions with certain image formats? > Now you come up asking for fancy features like passing device tree > information (and probably boot arguments as well? and ATAGs in case of > an ARM kernel? and ... ?) which goes way beyond the "just run it in > place", and also way beyond what "any other loader can". Are you really claiming that booting a Linux zImage is "way beyond what any other loader can" do? I'm pretty sure I've seen that happen on RedBoot, PlanetCore, and probably half a dozen others that I've forgotten. > Yes, U-Boot supports all this stuff. It is supported in the context of > U-Boot images, usign FIT images as the recommended format, and still > supporting the old legacy image format. So in other words, for booting an OS, U-Boot insists on particular image formats. > > It seems like it should be an orthogonal issue. At most it would > > require the user to specify an argument to the go command, that > > The go command takes arguments, which get passed to the started > application in the standard C calling convention. It is up to the > image to interpret these, then. It passes *text* arguments supplied by the command line, in argc/argv format. Which seems like it's not intended to be an arbitrary image loading command, but rather a facility to execute things that look and feel like shell commands. > > > But then - which other popular ARM boot loader supports passing a > > > device tree? Or which other popular embedded boot loader? > > > > It's not a matter of whether it's a device tree versus something else, > > but whether it is whatever Linux normally expects a loader to pass > > (e.g. ATAGs). > > For a "simple binary" that we "just run in place"? Yes. "simple" refers to the image format, not the calling convention. -Scott _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
