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arm64: dts: pfc-am62x: reserve U-Boot IPC sidecar shared memory

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Reserve 4 KB at 0x9c900000 (uboot-ipc-shm) in the Linux device tree so
the kernel never allocates pages over the DDR region that U-Boot uses
to pass LED commands to the M4 Zephyr firmware via the sidecar IPC
channel.

This region is written exclusively by U-Boot (A53) and read by the M4.
Linux only needs to know to stay away from it.

Signed-off-by: Heinrich Toews <ht@twx-software.de>
This commit is contained in:
Heinrich Toews
2026-04-21 11:53:16 +02:00
parent e1bec12f13
commit 5e5eafaa9a
1 changed files with 11 additions and 0 deletions
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arch/arm64/boot/dts/ti/k3-am623-pfc-750-8xxx-common.dtsi
+11
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@@ -110,6 +110,17 @@
no-map;
};
/*
* U-Boot IPC side-door shared memory.
* Written by U-Boot (A53) to send LED commands to the M4.
* Must not be touched by the Linux kernel.
* See UBOOT_IPC_SHMEM_PHYS in wago_m4_led_protocol.h.
*/
uboot_ipc_shm: uboot-ipc-shm@9cbff000 {
reg = <0x00 0x9cbff000 0x00 0x1000>;
no-map;
};
mcu_m4fss_dma_memory_region: m4f-dma-memory@9cb00000 {
compatible = "shared-dma-pool";
reg = <0x00 0x9cb00000 0x00 0x100000>;