arm: mediatek: add support for MediaTek MT7986 SoC
This patch adds basic support for MediaTek MT7986 SoC.
This include the file that will initialize the SoC after boot and its
device tree.
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Daniel Golle <daniel@makrotopia.org>
diff --git a/arch/arm/mach-mediatek/mt7986/lowlevel_init.S b/arch/arm/mach-mediatek/mt7986/lowlevel_init.S
new file mode 100644
index 0000000..85a1cea
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7986/lowlevel_init.S
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022 MediaTek Inc.
+ * Author: Sam Shih <sam.shih@mediatek.com>
+ */
+
+/*
+ * Switch from AArch64 EL2 to AArch32 EL2
+ * @param inputs:
+ * x0: argument, zero
+ * x1: machine nr
+ * x2: fdt address
+ * x3: input argument
+ * x4: kernel entry point
+ * @param outputs for secure firmware:
+ * x0: function id
+ * x1: kernel entry point
+ * x2: machine nr
+ * x3: fdt address
+ *
+ * [1] https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/tree/plat/mediatek/common/mtk_sip_svc.c
+*/
+
+.global armv8_el2_to_aarch32
+armv8_el2_to_aarch32:
+ mov x3, x2
+ mov x2, x1
+ mov x1, x4
+ mov x4, #0
+ ldr x0, =0x82000200 /* MTK_SIP_KERNEL_BOOT_AARCH32 */
+ SMC #0
+ ret