LoongArch: Add boot and setup routines

Add basic boot, setup and reset routines for LoongArch. Now, LoongArch
machines use UEFI-based firmware. The firmware passes configuration
information to the kernel via ACPI and DMI/SMBIOS.

Currently an existing interface between the kernel and the bootloader
is implemented. Kernel gets 2 values from the bootloader, passed in
registers a0 and a1; a0 is an "EFI boot flag" distinguishing UEFI and
non-UEFI firmware, while a1 is a pointer to an FDT with systable,
memmap, cmdline and initrd information.

The standard UEFI boot protocol (EFISTUB) will be added later.

Cc: linux-efi@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Co-developed-by: Yun Liu <liuyun@loongson.cn>
Signed-off-by: Yun Liu <liuyun@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 41 insertions, 0 deletions

diff --git a/arch/loongarch/include/asm/efi.h b/arch/loongarch/include/asm/efi.h
new file mode 100644
index 000000000000..0127d84d5e1d
--- /dev/null
+++ b/arch/loongarch/include/asm/efi.h
@@ -0,0 +1,41 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_LOONGARCH_EFI_H
+#define _ASM_LOONGARCH_EFI_H
+
+#include <linux/efi.h>
+
+void __init efi_init(void);
+void __init efi_runtime_init(void);
+void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
+
+#define ARCH_EFI_IRQ_FLAGS_MASK  0x00000004  /* Bit 2: CSR.CRMD.IE */
+
+#define arch_efi_call_virt_setup()               \
+({                                               \
+})
+
+#define arch_efi_call_virt(p, f, args...)        \
+({                                               \
+	efi_##f##_t * __f;                       \
+	__f = p->f;                              \
+	__f(args);                               \
+})
+
+#define arch_efi_call_virt_teardown()            \
+({                                               \
+})
+
+#define EFI_ALLOC_ALIGN		SZ_64K
+
+struct screen_info *alloc_screen_info(void);
+void free_screen_info(struct screen_info *si);
+
+static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
+{
+	return ULONG_MAX;
+}
+
+#endif /* _ASM_LOONGARCH_EFI_H */