ivshmem: Add header file

Common defines and structures for the ivshmem device.

Acked-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

include/linux/ivshmem.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _LINUX_IVSHMEM_H
+#define _LINUX_IVSHMEM_H
+
+#include <linux/types.h>
+
+#define IVSHM_PROTO_UNDEFINED		0x0000
+#define IVSHM_PROTO_NET			0x0001
+#define IVSHM_PROTO_VIRTIO_FRONT	0x8000
+#define IVSHM_PROTO_VIRTIO_BACK		0xc000
+#define IVSHM_PROTO_VIRTIO_DEVID_MASK	0x7fff
+
+#define IVSHM_CFG_PRIV_CNTL		0x03
+# define IVSHM_PRIV_CNTL_ONESHOT_INT	BIT(0)
+#define IVSHM_CFG_STATE_TAB_SZ		0x04
+#define IVSHM_CFG_RW_SECTION_SZ		0x08
+#define IVSHM_CFG_OUTPUT_SECTION_SZ	0x10
+#define IVSHM_CFG_ADDRESS		0x18
+
+struct ivshm_regs {
+	u32 id;
+	u32 max_peers;
+	u32 int_control;
+	u32 doorbell;
+	u32 state;
+};
+
+#define IVSHM_INT_ENABLE		BIT(0)
+
+#endif /* _LINUX_IVSHMEM_H */