Hi Siarhei, On Fri, Jul 28, 2017 at 11:15:44PM +0300, Siarhei Siamashka wrote: > On Fri, 28 Jul 2017 18:08:31 +0200 > Maxime Ripard <maxime.rip...@free-electrons.com> wrote: > > > On Thu, Jul 27, 2017 at 10:19:44PM -0600, Simon Glass wrote: > > > Hi Maxime, > > > > > > On 17 July 2017 at 03:26, Maxime Ripard > > > <maxime.rip...@free-electrons.com> wrote: > > > > Hi Simon, > > > > > > > > On Fri, Jul 14, 2017 at 07:47:45AM -0600, Simon Glass wrote: > > > >> On 5 July 2017 at 14:14, Maxime Ripard > > > >> <maxime.rip...@free-electrons.com> wrote: > > > >> > On Wed, Jul 05, 2017 at 04:57:40PM +0200, Maxime Ripard wrote: > > > >> >> On Tue, Jul 04, 2017 at 01:33:25PM -0600, Simon Glass wrote: > > > >> >> > Hi Maxime, > > > >> >> > > > > >> >> > On 21 June 2017 at 01:31, Maxime Ripard > > > >> >> > <maxime.rip...@free-electrons.com> wrote: > > > >> >> > > Hi Simon, > > > >> >> > > > > > >> >> > > On Mon, Jun 19, 2017 at 11:11:27AM -0600, Simon Glass wrote: > > > >> >> > >> Add a driver-model version of this driver which mostly uses > > > >> >> > >> the existing > > > >> >> > >> code. The old code can be removed once all boards are switched > > > >> >> > >> over. > > > >> >> > >> > > > >> >> > >> Signed-off-by: Simon Glass <s...@chromium.org> > > > >> >> > > > > > >> >> > > I'm not sure if you tested that, but we have some code that > > > >> >> > > switches > > > >> >> > > the MMC indices when using both an eMMC and an external MMC. > > > >> >> > > > > > >> >> > > http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/board.c#l494 > > > >> >> > > > > > >> >> > > This predates my time, but it seems that it was done to have a > > > >> >> > > consistent boot MMC device ID. > > > >> >> > > > > > >> >> > > I'm not really sure we can get rid of it (even if it creates > > > >> >> > > some > > > >> >> > > issues of it's own), but what would be the impact of a switch > > > >> >> > > to the > > > >> >> > > device model on that logic? > > > >> >> > > > > >> >> > That is a pretty terrible hack. > > > >> >> > > > >> >> Yes, I know. This is especially bad when used together with other > > > >> >> tools that rely on one MMC index for example (such as fastboot). > > > >> >> > > > >> >> I wanted to kill it for quite some time, but I'm a bit reluctant due > > > >> >> to the possible side effects. > > > >> >> > > > >> >> > I'm not sure whether it will continue to work with DM. It does > > > >> >> > still > > > >> >> > use the device number in the block device, so maybe... Do you > > > >> >> > have > > > >> >> > a board would use this? > > > >> >> > > > >> >> I guess I do. I'll give it a try or tonight and let you know. > > > >> > > > > >> > I just tested. Even with an eMMC (which was the first use case for > > > >> > that hack), it works, even things that are not mainline yet > > > >> > (fastboot, > > > >> > etc). > > > >> > > > > >> > It obviously break the old scripts relying on the mmc index, but I > > > >> > guess that's ok. > > > >> > > > > >> > There's one regression though. Our eMMC will always be the second > > > >> > one, > > > >> > which means that the distro bootargs will always boot on the external > > > >> > SD first (which is always going to be mmc0). > > > >> > > > > >> > That's due to the fact that the eMMC controller is the third one, and > > > >> > is thus probed last. We obviously want something deterministic for > > > >> > fastboot for example, but booting partitions of the media you started > > > >> > from make sense I guess. And this is what this hack was trying to > > > >> > address. > > > >> > > > >> OK...so what should we do here? > > > > > > > > I guess we should just drop the hack. We'll have to at some point > > > > anyway. But I guess we should also find a way to tweak the distro > > > > bootcmd at boot time to search for the medium that we booted on first. > > > > > > > > I'm not really sure how to do this though. > > You can check how this is done for USB FEL boot. Basically, we set an > environment variable if we see that the boot source is FEL: > > http://git.denx.de/?p=u-boot.git;a=commitdiff;h=af654d14613f22f4910601d86e584030ee392b94 > > And then check this environment variable from bootcmd: > > http://git.denx.de/?p=u-boot.git;a=commitdiff;h=f3b589c09b43a231706f11ab391e5ea7f9670f12 > > This can be done in a pretty much the same way for eMMC. Or maybe even > generalized to also use this for different boot sources and non-sunxi > SoCs.
That looks like a good solution, we'll give it a shot. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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