Hello Ahmad, On Mon, Mar 07, 2022 at 12:34:19PM +0100, Ahmad Fatoum wrote: > On 07.03.22 12:23, Uwe Kleine-König wrote: > > Having the mmc aliases in stm32mp151.dtsi is surprising as depending on > > the order of includes these override the mmc ordering in > > <arm/stm32mp157c-myboard.dts>. Also the ordering of mmc devices is actually > > board specific, so it's also right to have this in the board.dts files. > > NACK. I feared you'd oppose. :-\ My motivation to deviate from the default ordering is that I want to have eMMC as first device and SD as second, so on the board I have here I'd like to have mmc0 = &sdmmc2; /* eMMC */ mmc1 = &sdmmc1; /* µSD */ However in combination with arch/arm/dts/stm32mp151.dtsi this results in mmc0 = &sdmmc2; /* eMMC */ mmc1 = &sdmmc1; /* µSD */ mmc2 = &sdmmc3; which is a bit ugly because sdmmc3 isn't used at all on the board in question. Doing a /delete-property/mmc2 isn't that nice, too. Open for alternatives ... > MMC IPs have fixed numbering, because TF-A (and BootROM before it) > report to barebox the number of the MMC device that it succesfully booted from. > The aliases map these IDs to device tree nodes, so barebox can fix up a correct > /chosen/bootsource. And mapping the number from TF-A (or BootROM) depends on the aliases defined in the dts? Sounds like a bug to me. > Additionally having any alias at all ensures fixed naming that's > not dependent on probe order. Fine for me. And if the board doesn't define the aliases, you get random ordering. > I know that Linux maintainers seem to disagree with this, but as far > as barebox is concerned, aliases are SoC-specific, not board-specific > in general. You can override this board-level if you like, but the > default should remain. > > > There is no (relevant) change intended by this patch. > > I have non-upstream boards that would be broken by this. This is not a reason to not take this patch, is it? > There's also a Phytec board in next that would be broken by this. > Whereas they had a fixed mmcX before, they would now have disk0, disk1 > or disk2 depending on probe order with this patch applied. Agreed, code in next should be adapted. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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