[PATCH v2] arm64: dts: ls1028a: make the eMMC and SD card controllers use fixed indices

[Vladimir Oltean]

As the boot order in the kernel continues to change, sometimes it may
happen that the eSDHC controller mmc at 2150000 (the one for eMMC) gets
probed before the one at mmc at 2140000 (for external SD cards). The effect
is that the eMMC controller gets the /dev/mmcblk0 name, and the SD card
gets /dev/mmcblk1.

Since the introduction of this SoC, that has never happened in practice,
even though it was never guaranteed in theory. Setting
"root=/dev/mmcblk0p2" in /proc/cmdline has always caused the kernel to
use the second partition from the SD card as the rootfs.

The NXP development boards are typically shipped with either
- LSDK, which uses "root=UUID=", or
- OpenIL, which uses "root=/dev/mmcblkNp2"

So for OpenIL, let's preserve that old behavior by adding some aliases
which create naming consistency (for LSDK it doesn't matter):
- the SD card controller uses /dev/mmcblk0
- the eMMC controller uses /dev/mmcblk1

For the Kontron SL28 boards, Michael Walle says that they are shipped
with "root=UUID=" already, so the probing order doesn't matter, but it
is more natural to him for /dev/mmcblk0 to be the eMMC, so let's do it
the other way around there.

The aliases are parsed by mmc_alloc_host() in drivers/mmc/core/host.c.

Cc: Ashish Kumar <Ashish.Kumar at nxp.com>
Cc: Yangbo Lu <yangbo.lu at nxp.com>
Cc: Michael Walle <michael at walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
---
 arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28.dts | 2 ++
 arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts          | 2 ++
 arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts          | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28.dts b/arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28.dts
index 8161dd237971..99a17c187aa8 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28.dts
@@ -23,6 +23,8 @@ aliases {
 		serial2 = &lpuart1;
 		spi0 = &fspi;
 		spi1 = &dspi2;
+		mmc0 = &esdhc1;
+		mmc1 = &esdhc;
 	};
 
 	buttons0 {
diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts b/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts
index 13cdc958ba3e..c0786b713791 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a-qds.dts
@@ -23,6 +23,8 @@ aliases {
 		gpio2 = &gpio3;
 		serial0 = &duart0;
 		serial1 = &duart1;
+		mmc0 = &esdhc;
+		mmc1 = &esdhc1;
 	};
 
 	chosen {
diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts b/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts
index 1efb61cff454..c1d1ba459307 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts
@@ -19,6 +19,8 @@ aliases {
 		crypto = &crypto;
 		serial0 = &duart0;
 		serial1 = &duart1;
+		mmc0 = &esdhc;
+		mmc1 = &esdhc1;
 	};
 
 	chosen {
-- 
2.25.1