arm: mediatek: add support for MediaTek MT7981 SoC

This patch adds basic support for MediaTek MT7981 SoC.
This include the file that will initialize the SoC after boot and its
device tree.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>

3 files changed, 81 insertions, 0 deletions

diff --git a/arch/arm/mach-mediatek/mt7981/Makefile b/arch/arm/mach-mediatek/mt7981/Makefile
new file mode 100644
index 0000000000..007eb4a367
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7981/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier:	GPL-2.0
+
+obj-y += init.o
+obj-y += lowlevel_init.o
diff --git a/arch/arm/mach-mediatek/mt7981/init.c b/arch/arm/mach-mediatek/mt7981/init.c
new file mode 100644
index 0000000000..4f77a3defb
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7981/init.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 MediaTek Inc.
+ * Author: Sam Shih <sam.shih@mediatek.com>
+ */
+
+#include <init.h>
+#include <asm/armv8/mmu.h>
+#include <asm/system.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	gd->ram_size = get_ram_size((void *)CONFIG_SYS_SDRAM_BASE, SZ_2G);
+
+	return 0;
+}
+
+void reset_cpu(ulong addr)
+{
+	psci_system_reset();
+}
+
+static struct mm_region mt7981_mem_map[] = {
+	{
+		/* DDR */
+		.virt = 0x40000000UL,
+		.phys = 0x40000000UL,
+		.size = 0x80000000UL,
+		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) | PTE_BLOCK_OUTER_SHARE,
+	}, {
+		.virt = 0x00000000UL,
+		.phys = 0x00000000UL,
+		.size = 0x40000000UL,
+		.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
+			 PTE_BLOCK_NON_SHARE |
+			 PTE_BLOCK_PXN | PTE_BLOCK_UXN
+	}, {
+		0,
+	}
+};
+
+struct mm_region *mem_map = mt7981_mem_map;
diff --git a/arch/arm/mach-mediatek/mt7981/lowlevel_init.S b/arch/arm/mach-mediatek/mt7981/lowlevel_init.S
new file mode 100644
index 0000000000..85a1cea359
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7981/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