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

From: Vladimir Oltean
Date: Thu Nov 19 2020 - 10:50:57 EST


As the boot order in the kernel continues to change, sometimes it may
happen that the eSDHC controller mmc@2150000 (the one for eMMC) gets
probed before the one at mmc@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.

Preserve that old behavior by adding some aliases which create naming
consistency:
- the SD card controller uses /dev/mmcblk0
- the eMMC controller uses /dev/mmcblk1

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

Cc: Ashish Kumar <Ashish.Kumar@xxxxxxx>
Cc: Yangbo Lu <yangbo.lu@xxxxxxx>
Cc: Michael Walle <michael@xxxxxxxx>
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
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..7d292999f8da 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 = &esdhc;
+ mmc1 = &esdhc1;
};

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