issei: initial driver skeleton

The ISSEI (Intel Silicon Security Engine Interface)
subsystem provides a communication channel between the host and the
Silicon Security Engine.

Prepare basic driver functions and character device
for user-space communication.
Add DMA access routines for ISSEI HECI devices.
Add of DMA-related structures and implementation of routines for
setting up DMA, as well as reading and writing DMA buffers.

Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Co-developed-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Vitaly Lubart <lubvital@gmail.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://patch.msgid.link/20260513-issei-for-upstream-v1-1-f590038678f9@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 69 insertions, 0 deletions

diff --git a/include/uapi/linux/issei.h b/include/uapi/linux/issei.h
new file mode 100644
index 000000000000..3bfb89330265
--- /dev/null
+++ b/include/uapi/linux/issei.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright (C) 2023-2026 Intel Corporation
+ * Intel Silicon Security Engine Interface (ISSEI) Linux driver:
+ * ISSEI Interface Header
+ */
+#ifndef _LINUX_ISSEI_H
+#define _LINUX_ISSEI_H
+
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/*
+ * This ioctl is used to associate the current file descriptor with a
+ * FW Client (given by UUID). This opens a communication channel
+ * between a host client and a FW client. From this point every read and write
+ * will communicate with the associated FW client.
+ * The communication between the clients can be terminated by
+ * IOCTL_ISSEI_DISCONNECT_CLIENT IOCTL or by
+ * closing the file descriptor (file_operation release()).
+ *
+ * The ioctl argument is a struct with a union that contains
+ * the input parameter and the output parameter for this ioctl.
+ *
+ * The input parameter is UUID of the FW Client.
+ * The output parameter is the properties of the FW client
+ * (FW protocol version, max message size and client flags).
+ */
+#define IOCTL_ISSEI_CONNECT_CLIENT \
+	_IOWR('H', 0x01, struct issei_connect_client_data)
+
+/**
+ * struct issei_client - ISSEI client information structure
+ * @max_msg_length: maximum message length supported by the firmware client (in bytes)
+ * @protocol_version: protocol version reported by the firmware client
+ * @reserved1: reserved
+ * @flags: flag bitmask reported by the firmware client
+ * @reserved2: reserved
+ */
+struct issei_client {
+	__u32 max_msg_length;
+	__u8 protocol_version;
+	__u8 reserved1[3];
+	__u32 flags;
+	__u32 reserved2;
+};
+
+#define ISSEI_IOCTL_UUID_LEN 16
+
+/**
+ * struct issei_connect_client_data - ioctl Connect Client Data structure
+ * @in_client_uuid: unique id of the firmware client to connect to (from user space to kernel)
+ * @out_client_properties: connected firmware client properties (from kernel to user space)
+ */
+struct issei_connect_client_data {
+	union {
+		__u8 in_client_uuid[ISSEI_IOCTL_UUID_LEN];
+		struct issei_client out_client_properties;
+	};
+};
+
+/*
+ * This ioctl is used to terminate association between
+ * the host client and the FW client.
+ */
+#define IOCTL_ISSEI_DISCONNECT_CLIENT \
+	_IO('H', 0x02)
+
+#endif /* _LINUX_ISSEI_H */