overlays: Add disable-emmc2

Add a new overlay that disables the EMMC2 controller on BCM2711.
This can be useful on a Compute Module 4 if the onboard EMMC2
storage is unreliable and the system can be booted by other
means e.g Network / USB.

Signed-off-by: Tim Gover <tim.gover@raspberrypi.com>

diff --git a/arch/arm/boot/dts/overlays/Makefile b/arch/arm/boot/dts/overlays/Makefile
index dac6fce..edd149a 100644 (file)
--- a/arch/arm/boot/dts/overlays/Makefile
+++ b/arch/arm/boot/dts/overlays/Makefile
@@ -49,6 +49,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
        dionaudio-loco.dtbo \
        dionaudio-loco-v2.dtbo \
        disable-bt.dtbo \
+       disable-emmc2.dtbo \
        disable-wifi.dtbo \
        dpi18.dtbo \
        dpi18cpadhi.dtbo \

diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README
index 85b6106..8369d18 100644 (file)
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -895,6 +895,14 @@ Load:   dtoverlay=disable-bt
 Params: <None>
 
 
+Name:   disable-emmc2
+Info:   Disable EMMC2 controller on BCM2711.
+        The allows the onboard EMMC storage on Compute Module 4 to be disabled
+        e.g. if a fault has occurred.
+Load:   dtoverlay=disable-emmc2
+Params: <None>
+
+
 Name:   disable-wifi
 Info:   Disable onboard WLAN on Pi 3B, 3B+, 3A+, 4B and Zero W.
 Load:   dtoverlay=disable-wifi

diff --git a/arch/arm/boot/dts/overlays/disable-emmc2-overlay.dts b/arch/arm/boot/dts/overlays/disable-emmc2-overlay.dts
new file mode 100644 (file)
index 0000000..8cd1d7f
--- /dev/null
+++ b/arch/arm/boot/dts/overlays/disable-emmc2-overlay.dts
@@ -0,0 +1,13 @@
+/dts-v1/;
+/plugin/;
+
+/{
+       compatible = "brcm,bcm2711";
+
+       fragment@0 {
+               target = <&emmc2>;
+               __overlay__ {
+                       status = "disabled";
+               };
+       };
+};

diff --git a/arch/arm/boot/dts/overlays/overlay_map.dts b/arch/arm/boot/dts/overlays/overlay_map.dts
index 627855b..fda0364 100644 (file)
--- a/arch/arm/boot/dts/overlays/overlay_map.dts
+++ b/arch/arm/boot/dts/overlays/overlay_map.dts
@@ -9,6 +9,10 @@
                bcm2711;
        };
 
+       disable-emmc2 {
+               bcm2711;
+       };
+
        highperi {
                bcm2711;
        };