[PATCH] ARM: dts: am33xx: add aliases for mmc interfaces

[PATCH] ARM: dts: am33xx: add aliases for mmc interfaces

[Mans Rullgard]

Without DT aliases, the numbering of mmc interfaces is unpredictable.
Adding them makes it possible to refer to devices consistently.  The
popular suggestion to use UUIDs obviously doesn't work with a blank
device fresh from the factory.

See fa2d0aa96941 "mmc: core: Allow setting slot index via device tree
alias" for more discussion.

Signed-off-by: Mans Rullgard <mans@mansr.com>
---
 arch/arm/boot/dts/am33xx.dtsi | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/boot/dts/am33xx.dtsi b/arch/arm/boot/dts/am33xx.dtsi
index 4c2298024137..f09a61cac2dc 100644
--- a/arch/arm/boot/dts/am33xx.dtsi
+++ b/arch/arm/boot/dts/am33xx.dtsi
@@ -40,6 +40,9 @@ aliases {
 		ethernet1 = &cpsw_emac1;
 		spi0 = &spi0;
 		spi1 = &spi1;
+		mmc0 = &mmc1;
+		mmc1 = &mmc2;
+		mmc2 = &mmc3;
 	};
 
 	cpus {
-- 
2.30.0

Re: [PATCH] ARM: dts: am33xx: add aliases for mmc interfaces

[Tony Lindgren]

* Måns Rullgård <mans@mansr.com> [210129 11:40]:
> Tony Lindgren <tony@atomide.com> writes:
> 
> > * Mans Rullgard <mans@mansr.com> [210128 18:09]:
> >> Without DT aliases, the numbering of mmc interfaces is unpredictable.
> >> Adding them makes it possible to refer to devices consistently.  The
> >> popular suggestion to use UUIDs obviously doesn't work with a blank
> >> device fresh from the factory.
> >> 
> >> See fa2d0aa96941 "mmc: core: Allow setting slot index via device tree
> >> alias" for more discussion.
> >
> > Sounds good to me, but will wait a few days before applying to make sure
> > this is still what we have agreed on :)
> 
> If it helps the decision, my existing systems fail to boot without
> something like this due to the eMMC moving from /dev/mmcblk1 to mmcblk0,
> at least sometimes.  I guess the kernel cares deeply about not breaking
> userspace, except when it doesn't give a damn.
> 
> I've been fighting this problem in various forms for the last 10 years
> or so, and I was hoping it would finally be over.

Yes this issue has been bugging folks for long time. Applying into fixes
thanks.

Tony