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@@ -0,0 +1,48 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * uefi-vars device - API of the virtual device for guest/host communication.
+ */
+#ifndef QEMU_UEFI_VAR_SERVICE_API_H
+#define QEMU_UEFI_VAR_SERVICE_API_H
+
+/* qom: device names */
+#define TYPE_UEFI_VARS_X64 "uefi-vars-x64"
+#define TYPE_UEFI_VARS_SYSBUS "uefi-vars-sysbus"
+
+/* sysbus: fdt node path */
+#define UEFI_VARS_FDT_NODE "qemu-uefi-vars"
+#define UEFI_VARS_FDT_COMPAT "qemu,uefi-vars"
+
+/* registers */
+#define UEFI_VARS_REG_MAGIC 0x00 /* 16 bit */
+#define UEFI_VARS_REG_CMD_STS 0x02 /* 16 bit */
+#define UEFI_VARS_REG_BUFFER_SIZE 0x04 /* 32 bit */
+#define UEFI_VARS_REG_DMA_BUFFER_ADDR_LO 0x08 /* 32 bit */
+#define UEFI_VARS_REG_DMA_BUFFER_ADDR_HI 0x0c /* 32 bit */
+#define UEFI_VARS_REG_PIO_BUFFER_TRANSFER 0x10 /* 8-64 bit */
+#define UEFI_VARS_REG_PIO_BUFFER_CRC32C 0x18 /* 32 bit (read-only) */
+#define UEFI_VARS_REG_FLAGS 0x1c /* 32 bit */
+#define UEFI_VARS_REGS_SIZE 0x20
+
+/* flags register */
+#define UEFI_VARS_FLAG_USE_PIO (1 << 0)
+
+/* magic value */
+#define UEFI_VARS_MAGIC_VALUE 0xef1
+
+/* command values */
+#define UEFI_VARS_CMD_RESET 0x01
+#define UEFI_VARS_CMD_DMA_MM 0x02
+#define UEFI_VARS_CMD_PIO_MM 0x03
+#define UEFI_VARS_CMD_PIO_ZERO_OFFSET 0x04
+
+/* status values */
+#define UEFI_VARS_STS_SUCCESS 0x00
+#define UEFI_VARS_STS_BUSY 0x01
+#define UEFI_VARS_STS_ERR_UNKNOWN 0x10
+#define UEFI_VARS_STS_ERR_NOT_SUPPORTED 0x11
+#define UEFI_VARS_STS_ERR_BAD_BUFFER_SIZE 0x12
+
+
+#endif /* QEMU_UEFI_VAR_SERVICE_API_H */