x86: Add support for running option ROMs natively

On x86 machines we can use an emulator to run option ROMS as with other
architectures. But with some additional effort (mostly due to the 16-bit
nature of option ROMs) we can run them natively. Add support for this.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/arch/x86/lib/bios.h b/arch/x86/lib/bios.h
new file mode 100644
index 0000000000..8491b4acdd
--- /dev/null
+++ b/arch/x86/lib/bios.h
@@ -0,0 +1,98 @@
+/*
+ * From Coreboot file device/oprom/realmode/x86.h
+ *
+ * Copyright (C) 2007 Advanced Micro Devices, Inc.
+ * Copyright (C) 2009-2010 coresystems GmbH
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#ifndef _X86_LIB_BIOS_H
+#define _X86_LIB_BIOS_H
+
+#define REALMODE_BASE		0x600
+
+#ifdef __ASSEMBLY__
+
+#define PTR_TO_REAL_MODE(x)	(x - asm_realmode_code + REALMODE_BASE)
+
+#else
+
+/* Convert a symbol address to our real mode area */
+#define PTR_TO_REAL_MODE(sym)\
+	(void *)(REALMODE_BASE + ((char *)&(sym) - (char *)&asm_realmode_code))
+
+/*
+ * The following symbols cannot be used directly. They need to be fixed up
+ * to point to the correct address location after the code has been copied
+ * to REALMODE_BASE. Absolute symbols are not used because those symbols are
+ * relocated by U-Boot.
+ */
+extern unsigned char asm_realmode_call, __realmode_interrupt;
+extern unsigned char asm_realmode_buffer;
+
+#define DOWNTO8(A) \
+	union { \
+		struct { \
+			union { \
+				struct { \
+					uint8_t A##l; \
+					uint8_t A##h; \
+				} __packed; \
+				uint16_t A##x; \
+			} __packed; \
+			uint16_t h##A##x; \
+		} __packed; \
+		uint32_t e##A##x; \
+	} __packed;
+
+#define DOWNTO16(A) \
+	union { \
+		struct { \
+			uint16_t A; \
+			uint16_t h##A; \
+		} __packed; \
+		uint32_t e##A; \
+	} __packed;
+
+struct eregs {
+	DOWNTO8(a);
+	DOWNTO8(c);
+	DOWNTO8(d);
+	DOWNTO8(b);
+	DOWNTO16(sp);
+	DOWNTO16(bp);
+	DOWNTO16(si);
+	DOWNTO16(di);
+	uint32_t vector;
+	uint32_t error_code;
+	uint32_t eip;
+	uint32_t cs;
+	uint32_t eflags;
+};
+
+struct realmode_idt {
+	u16 offset, cs;
+};
+
+void x86_exception(struct eregs *info);
+
+/* From x86_asm.S */
+extern unsigned char __idt_handler;
+extern unsigned int __idt_handler_size;
+extern unsigned char asm_realmode_code;
+extern unsigned int asm_realmode_code_size;
+
+asmlinkage void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx,
+				 u32 esi, u32 edi);
+
+asmlinkage void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx,
+				      u32 edx, u32 esi, u32 edi);
+
+int int10_handler(void);
+int int12_handler(void);
+int int16_handler(void);
+int int1a_handler(void);
+#endif /*__ASSEMBLY__ */
+
+#endif