1// SPDX-License-Identifier: (GPL-2.0+ OR MIT) 2/* 3 * Copyright (C) 2023 Marvell International Ltd. 4 * 5 * Device tree for the AC5X RD Type 7 Com Express carrier board, 6 * This specific board in external mode (see below) only maintains 7 * a PCIe link with the COM Express CPU module, which does not 8 * require any special DTS definitions. 9 * 10 * AC5X RD can either work as you would expect, as a complete standalone 11 * box using the internal CPU, or you can move the switch on the back of 12 * the box to "external" mode, and connect via an external cable a kit 13 * which would allow it to use an external CPU COM Express module, 14 * mounted on top of an interposer kit. 15 * 16 * So in this case, once the switch is set to external mode as explained above, 17 * the AC5X RD becomes part of the carrier solution. 18 * This is a development/reference solution, not a full commercial solution, 19 * hence it was designed with the flexibility to be configured in different 20 * modes of operation. 21 * 22 * When the board boots in the external CPU mode, the internal CPU is disabled, 23 * and only the switch portion of the SOC acts as a PCIe end-point, Hence there 24 * is no need to describe this internal (disabled CPU) in the device tree. 25 * 26 * There is no CPU booting in this mode on the carrier, 27 * only on the COM Express CPU module. 28 */ 29 30/ { 31 model = "Marvell Armada AC5X RD COM EXPRESS type 7 carrier board"; 32 compatible = "marvell,rd-ac5x-carrier"; 33 34}; 35