RPU (Zephyr) Device Tree Requirements - RPU (Zephyr) Device Tree Requirements - 2026.1 English - UG1186

Use the following device tree reference:

• GitHub repository: meta-amd-adaptive-socs
• File: versal-2ve-2vm-vek385-sdt-seg-cortexr52-0-zephyr.dts

1. Configure the chosen node:

   chosen {
       stdout-path = "serial1:115200n8";
       bootargs = "earlycon=pl011,mmio32,0xf1930000 console=ttyAMA1,115200";
       /* OpenAMP IPC shared memory region */
       zephyr,ipc_shm = "/reserved-memory/ipc@9860000";
       /* Firmware load region for ELF boot */
       zephyr,sram = "/reserved-memory/ddrboot@9800100";
   };
   

2. Review the key chosen properties:
   • zephyr,ipc_shm: Points to shared memory for VirtIO vrings and buffers
   • zephyr,sram: DDR region where Linux remoteproc loads the Zephyr ELF
3. Define reserved memory on the Zephyr side:

   reserved-memory {
       #size-cells = <0x2>;
       #address-cells = <0x2>;
       ranges;
       /* Firmware boot region - must match Linux DT */
       ddrboot@9800100 {
           phandle = <0x269>;
           device_type = "memory";
           no-map;
           reg = <0x0 0x9800100 0x0 0x5ff00>;
       };
       /* IPC shared memory - includes vrings and buffers */
       ipc@9860000 {
           phandle = <0x26b>;
           compatible = "mmio-sram";
           reg = <0x0 0x9860000 0x0 0x48000>;  /* 288 KB total */
       };
   };

   The ipc@9860000 region includes both vrings and the shared buffer pool (0x9860000 to 0x98a8000).
4. Configure the IPI mailbox on the Zephyr side:

   ipi_nobuf2: mailbox@eb3b1000 {
       compatible = "xlnx,mbox-versal-ipi-mailbox";
       interrupt-parent = <&gic_r52>;
       interrupts = <0x0 0x41 0x4 0xa0>;
       reg = <0x0 0xeb3b1000 0x0 0x1000>;
       xlnx,ipi-id = <0xb>;                    /* RPU IPI ID (no-buffer) */
       #address-cells = <0x2>;
       #size-cells = <0x2>;
       ranges;
       /* RPU to APU IPI channel */
       ipi_2_nobuf_to_ipi_1_nobuf: child@eb3b0000 {
           compatible = "xlnx,mbox-versal-ipi-dest-mailbox";
           #mbox-cells = <0x1>;
           xlnx,ipi-id = <0xa>;                /* Target APU no-buf IPI */
           reg = <0x0 0xeb3b0000 0x0 0x1000>;
           reg-names = "ctrl";
       };
   };
   /* Mailbox consumer binding for Zephyr IPC driver */
   mbox-consumer {
       compatible = "vnd,mbox-consumer";
       mboxes = <&ipi_2_nobuf_to_ipi_1_nobuf 0x0>,  /* TX to APU */
                <&ipi_2_nobuf_to_ipi_1_nobuf 0x1>;  /* RX from APU */
       mbox-names = "tx", "rx";
   };

5. Configure the Zephyr firmware:
   1. Use the OpenAMP System Reference - RPMsg Multi Services application.
   2. Project configuration (prj.conf):

      CONFIG_KERNEL_BIN_NAME="rpmsg_multi_services"
      CONFIG_PRINTK=n
      CONFIG_IPM=y
      CONFIG_MAIN_STACK_SIZE=1024
      CONFIG_HEAP_MEM_POOL_SIZE=1024
      CONFIG_OPENAMP=y
      CONFIG_OPENAMP_RSC_TABLE_NUM_RPMSG_BUFF=8
      CONFIG_OPENAMP_RSC_TABLE=y
      CONFIG_OPENAMP_MASTER=n

6. Review the application structure
   • src/main_remote.c: main application that implements RPMsg endpoints
   • boards/: board-specific overlays; use kv260_r5.overlay as a reference for Zynq
   • prj.conf: Zephyr project configuration
   • CMakeLists.txt: build configuration