Adding upstream version 6.9.2.upstream/6.9.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 419 insertions, 1 deletions

diff --git a/drivers/gpu/drm/xe/abi/gsc_proxy_commands_abi.h b/drivers/gpu/drm/xe/abi/gsc_proxy_commands_abi.h
new file mode 100644
index 000000000..80bbf06a3
--- /dev/null
+++ b/drivers/gpu/drm/xe/abi/gsc_proxy_commands_abi.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef _ABI_GSC_PROXY_COMMANDS_ABI_H
+#define _ABI_GSC_PROXY_COMMANDS_ABI_H
+
+#include <linux/types.h>
+
+/* Heci client ID for proxy commands */
+#define HECI_MEADDRESS_PROXY 10
+
+/* FW-defined proxy header */
+struct xe_gsc_proxy_header {
+	/*
+	 * hdr:
+	 * Bits 0-7: type of the proxy message (see enum xe_gsc_proxy_type)
+	 * Bits 8-15: rsvd
+	 * Bits 16-31: length in bytes of the payload following the proxy header
+	 */
+	u32 hdr;
+#define GSC_PROXY_TYPE		 GENMASK(7, 0)
+#define GSC_PROXY_PAYLOAD_LENGTH GENMASK(31, 16)
+
+	u32 source;		/* Source of the Proxy message */
+	u32 destination;	/* Destination of the Proxy message */
+#define GSC_PROXY_ADDRESSING_KMD  0x10000
+#define GSC_PROXY_ADDRESSING_GSC  0x20000
+#define GSC_PROXY_ADDRESSING_CSME 0x30000
+
+	u32 status;		/* Command status */
+} __packed;
+
+/* FW-defined proxy types */
+enum xe_gsc_proxy_type {
+	GSC_PROXY_MSG_TYPE_PROXY_INVALID = 0,
+	GSC_PROXY_MSG_TYPE_PROXY_QUERY = 1,
+	GSC_PROXY_MSG_TYPE_PROXY_PAYLOAD = 2,
+	GSC_PROXY_MSG_TYPE_PROXY_END = 3,
+	GSC_PROXY_MSG_TYPE_PROXY_NOTIFICATION = 4,
+};
+
+#endif
diff --git a/drivers/gpu/drm/xe/abi/guc_actions_sriov_abi.h b/drivers/gpu/drm/xe/abi/guc_actions_sriov_abi.h
new file mode 100644
index 000000000..5496a5890
--- /dev/null
+++ b/drivers/gpu/drm/xe/abi/guc_actions_sriov_abi.h
@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef _GUC_ACTIONS_PF_ABI_H
+#define _GUC_ACTIONS_PF_ABI_H
+
+#include "guc_communication_ctb_abi.h"
+
+/**
+ * DOC: GUC2PF_RELAY_FROM_VF
+ *
+ * This message is used by the GuC firmware to forward a VF2PF `Relay Message`_
+ * received from the Virtual Function (VF) driver to this Physical Function (PF)
+ * driver.
+ *
+ * This message is always sent as `CTB HXG Message`_.
+ *
+ *  +---+-------+--------------------------------------------------------------+
+ *  |   | Bits  | Description                                                  |
+ *  +===+=======+==============================================================+
+ *  | 0 |    31 | ORIGIN = GUC_HXG_ORIGIN_GUC_                                 |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 30:28 | TYPE = GUC_HXG_TYPE_EVENT_                                   |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 27:16 | MBZ                                                          |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   |  15:0 | ACTION = _`XE_GUC_ACTION_GUC2PF_RELAY_FROM_VF` = 0x5100      |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 1 |  31:0 | **VFID** - source VF identifier                              |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 2 |  31:0 | **RELAY_ID** - VF/PF message ID                              |
+ *  +---+-------+-----------------+--------------------------------------------+
+ *  | 3 |  31:0 | **RELAY_DATA1** |                                            |
+ *  +---+-------+-----------------+                                            |
+ *  |...|       |                 |       [Embedded `Relay Message`_]          |
+ *  +---+-------+-----------------+                                            |
+ *  | n |  31:0 | **RELAY_DATAx** |                                            |
+ *  +---+-------+-----------------+--------------------------------------------+
+ */
+#define XE_GUC_ACTION_GUC2PF_RELAY_FROM_VF		0x5100
+
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_MIN_LEN		(GUC_HXG_EVENT_MSG_MIN_LEN + 2u)
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_MAX_LEN \
+	(GUC2PF_RELAY_FROM_VF_EVENT_MSG_MIN_LEN + GUC_RELAY_MSG_MAX_LEN)
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_0_MBZ		GUC_HXG_EVENT_MSG_0_DATA0
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_1_VFID		GUC_HXG_EVENT_MSG_n_DATAn
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_2_RELAY_ID	GUC_HXG_EVENT_MSG_n_DATAn
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_3_RELAY_DATA1	GUC_HXG_EVENT_MSG_n_DATAn
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_n_RELAY_DATAx	GUC_HXG_EVENT_MSG_n_DATAn
+#define GUC2PF_RELAY_FROM_VF_EVENT_MSG_NUM_RELAY_DATA	GUC_RELAY_MSG_MAX_LEN
+
+/**
+ * DOC: PF2GUC_RELAY_TO_VF
+ *
+ * This H2G message is used by the Physical Function (PF) driver to send embedded
+ * VF2PF `Relay Message`_ to the VF.
+ *
+ * This action message must be sent over CTB as `CTB HXG Message`_.
+ *
+ *  +---+-------+--------------------------------------------------------------+
+ *  |   | Bits  | Description                                                  |
+ *  +===+=======+==============================================================+
+ *  | 0 |    31 | ORIGIN = GUC_HXG_ORIGIN_HOST_                                |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 30:28 | TYPE = `GUC_HXG_TYPE_FAST_REQUEST`_                          |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 27:16 | MBZ                                                          |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   |  15:0 | ACTION = _`XE_GUC_ACTION_PF2GUC_RELAY_TO_VF` = 0x5101        |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 1 |  31:0 | **VFID** - target VF identifier                              |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 2 |  31:0 | **RELAY_ID** - VF/PF message ID                              |
+ *  +---+-------+-----------------+--------------------------------------------+
+ *  | 3 |  31:0 | **RELAY_DATA1** |                                            |
+ *  +---+-------+-----------------+                                            |
+ *  |...|       |                 |       [Embedded `Relay Message`_]          |
+ *  +---+-------+-----------------+                                            |
+ *  | n |  31:0 | **RELAY_DATAx** |                                            |
+ *  +---+-------+-----------------+--------------------------------------------+
+ */
+#define XE_GUC_ACTION_PF2GUC_RELAY_TO_VF		0x5101
+
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_MIN_LEN		(GUC_HXG_REQUEST_MSG_MIN_LEN + 2u)
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_MAX_LEN \
+	(PF2GUC_RELAY_TO_VF_REQUEST_MSG_MIN_LEN + GUC_RELAY_MSG_MAX_LEN)
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_0_MBZ		GUC_HXG_REQUEST_MSG_0_DATA0
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_1_VFID		GUC_HXG_REQUEST_MSG_n_DATAn
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_2_RELAY_ID	GUC_HXG_REQUEST_MSG_n_DATAn
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_3_RELAY_DATA1	GUC_HXG_REQUEST_MSG_n_DATAn
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_n_RELAY_DATAx	GUC_HXG_REQUEST_MSG_n_DATAn
+#define PF2GUC_RELAY_TO_VF_REQUEST_MSG_NUM_RELAY_DATA	GUC_RELAY_MSG_MAX_LEN
+
+/**
+ * DOC: GUC2VF_RELAY_FROM_PF
+ *
+ * This message is used by the GuC firmware to deliver `Relay Message`_ from the
+ * Physical Function (PF) driver to this Virtual Function (VF) driver.
+ * See `GuC Relay Communication`_ for details.
+ *
+ * This message is always sent over CTB.
+ *
+ *  +---+-------+--------------------------------------------------------------+
+ *  |   | Bits  | Description                                                  |
+ *  +===+=======+==============================================================+
+ *  | 0 |    31 | ORIGIN = GUC_HXG_ORIGIN_GUC_                                 |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 30:28 | TYPE = GUC_HXG_TYPE_EVENT_                                   |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 27:16 | MBZ                                                          |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   |  15:0 | ACTION = _`XE_GUC_ACTION_GUC2VF_RELAY_FROM_PF` = 0x5102      |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 1 |  31:0 | **RELAY_ID** - VF/PF message ID                              |
+ *  +---+-------+-----------------+--------------------------------------------+
+ *  | 2 |  31:0 | **RELAY_DATA1** |                                            |
+ *  +---+-------+-----------------+                                            |
+ *  |...|       |                 |       [Embedded `Relay Message`_]          |
+ *  +---+-------+-----------------+                                            |
+ *  | n |  31:0 | **RELAY_DATAx** |                                            |
+ *  +---+-------+-----------------+--------------------------------------------+
+ */
+#define XE_GUC_ACTION_GUC2VF_RELAY_FROM_PF		0x5102
+
+#define GUC2VF_RELAY_FROM_PF_EVENT_MSG_MIN_LEN		(GUC_HXG_EVENT_MSG_MIN_LEN + 1u)
+#define GUC2VF_RELAY_FROM_PF_EVENT_MSG_MAX_LEN \
+	(GUC2VF_RELAY_FROM_PF_EVENT_MSG_MIN_LEN + GUC_RELAY_MSG_MAX_LEN)
+#define GUC2VF_RELAY_FROM_PF_EVENT_MSG_0_MBZ		GUC_HXG_EVENT_MSG_0_DATA0
+#define GUC2VF_RELAY_FROM_PF_EVENT_MSG_1_RELAY_ID	GUC_HXG_EVENT_MSG_n_DATAn
+#define GUC2VF_RELAY_FROM_PF_EVENT_MSG_n_RELAY_DATAx	GUC_HXG_EVENT_MSG_n_DATAn
+#define GUC2VF_RELAY_FROM_PF_EVENT_MSG_NUM_RELAY_DATA	GUC_RELAY_MSG_MAX_LEN
+
+/**
+ * DOC: VF2GUC_RELAY_TO_PF
+ *
+ * This message is used by the Virtual Function (VF) drivers to communicate with
+ * the Physical Function (PF) driver and send `Relay Message`_ to the PF driver.
+ * See `GuC Relay Communication`_ for details.
+ *
+ * This message must be sent over CTB.
+ *
+ *  +---+-------+--------------------------------------------------------------+
+ *  |   | Bits  | Description                                                  |
+ *  +===+=======+==============================================================+
+ *  | 0 |    31 | ORIGIN = GUC_HXG_ORIGIN_HOST_                                |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 30:28 | TYPE = GUC_HXG_TYPE_REQUEST_ or GUC_HXG_TYPE_FAST_REQUEST_   |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 27:16 | MBZ                                                          |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   |  15:0 | ACTION = _`XE_GUC_ACTION_VF2GUC_RELAY_TO_PF` = 0x5103        |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 1 |  31:0 | **RELAY_ID** - VF/PF message ID                              |
+ *  +---+-------+-----------------+--------------------------------------------+
+ *  | 2 |  31:0 | **RELAY_DATA1** |                                            |
+ *  +---+-------+-----------------+                                            |
+ *  |...|       |                 |       [Embedded `Relay Message`_]          |
+ *  +---+-------+-----------------+                                            |
+ *  | n |  31:0 | **RELAY_DATAx** |                                            |
+ *  +---+-------+-----------------+--------------------------------------------+
+ */
+#define XE_GUC_ACTION_VF2GUC_RELAY_TO_PF		0x5103
+
+#define VF2GUC_RELAY_TO_PF_REQUEST_MSG_MIN_LEN		(GUC_HXG_REQUEST_MSG_MIN_LEN + 1u)
+#define VF2GUC_RELAY_TO_PF_REQUEST_MSG_MAX_LEN \
+	(VF2GUC_RELAY_TO_PF_REQUEST_MSG_MIN_LEN + GUC_RELAY_MSG_MAX_LEN)
+#define VF2GUC_RELAY_TO_PF_REQUEST_MSG_0_MBZ		GUC_HXG_REQUEST_MSG_0_DATA0
+#define VF2GUC_RELAY_TO_PF_REQUEST_MSG_1_RELAY_ID	GUC_HXG_REQUEST_MSG_n_DATAn
+#define VF2GUC_RELAY_TO_PF_REQUEST_MSG_n_RELAY_DATAx	GUC_HXG_REQUEST_MSG_n_DATAn
+#define VF2GUC_RELAY_TO_PF_REQUEST_MSG_NUM_RELAY_DATA	GUC_RELAY_MSG_MAX_LEN
+
+#endif
diff --git a/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h b/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h
index 0b1146d0c..8f86a16dc 100644
--- a/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h
+++ b/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h
@@ -81,12 +81,13 @@ static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
 
 #define GUC_CTB_HDR_LEN				1u
 #define GUC_CTB_MSG_MIN_LEN			GUC_CTB_HDR_LEN
-#define GUC_CTB_MSG_MAX_LEN			256u
+#define GUC_CTB_MSG_MAX_LEN			(GUC_CTB_MSG_MIN_LEN + GUC_CTB_MAX_DWORDS)
 #define GUC_CTB_MSG_0_FENCE			(0xffffu << 16)
 #define GUC_CTB_MSG_0_FORMAT			(0xfu << 12)
 #define   GUC_CTB_FORMAT_HXG			0u
 #define GUC_CTB_MSG_0_RESERVED			(0xfu << 8)
 #define GUC_CTB_MSG_0_NUM_DWORDS		(0xffu << 0)
+#define   GUC_CTB_MAX_DWORDS			255
 
 /**
  * DOC: CTB HXG Message
diff --git a/drivers/gpu/drm/xe/abi/guc_messages_abi.h b/drivers/gpu/drm/xe/abi/guc_messages_abi.h
index 29e414c82..534a39db7 100644
--- a/drivers/gpu/drm/xe/abi/guc_messages_abi.h
+++ b/drivers/gpu/drm/xe/abi/guc_messages_abi.h
@@ -24,6 +24,7 @@
  *  |   | 30:28 | **TYPE** - message type                                      |
  *  |   |       |   - _`GUC_HXG_TYPE_REQUEST` = 0                              |
  *  |   |       |   - _`GUC_HXG_TYPE_EVENT` = 1                                |
+ *  |   |       |   - _`GUC_HXG_TYPE_FAST_REQUEST` = 2                         |
  *  |   |       |   - _`GUC_HXG_TYPE_NO_RESPONSE_BUSY` = 3                     |
  *  |   |       |   - _`GUC_HXG_TYPE_NO_RESPONSE_RETRY` = 5                    |
  *  |   |       |   - _`GUC_HXG_TYPE_RESPONSE_FAILURE` = 6                     |
@@ -46,6 +47,7 @@
 #define GUC_HXG_MSG_0_TYPE			(0x7u << 28)
 #define   GUC_HXG_TYPE_REQUEST			0u
 #define   GUC_HXG_TYPE_EVENT			1u
+#define   GUC_HXG_TYPE_FAST_REQUEST		2u
 #define   GUC_HXG_TYPE_NO_RESPONSE_BUSY		3u
 #define   GUC_HXG_TYPE_NO_RESPONSE_RETRY	5u
 #define   GUC_HXG_TYPE_RESPONSE_FAILURE		6u
diff --git a/drivers/gpu/drm/xe/abi/guc_relay_actions_abi.h b/drivers/gpu/drm/xe/abi/guc_relay_actions_abi.h
new file mode 100644
index 000000000..747e428de
--- /dev/null
+++ b/drivers/gpu/drm/xe/abi/guc_relay_actions_abi.h
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef _ABI_GUC_RELAY_ACTIONS_ABI_H_
+#define _ABI_GUC_RELAY_ACTIONS_ABI_H_
+
+/**
+ * DOC: GuC Relay Debug Actions
+ *
+ * This range of action codes is reserved for debugging purposes only and should
+ * be used only on debug builds. These actions may not be supported by the
+ * production drivers. Their definitions could be changed in the future.
+ *
+ *  _`GUC_RELAY_ACTION_DEBUG_ONLY_START` = 0xDEB0
+ *  _`GUC_RELAY_ACTION_DEBUG_ONLY_END` = 0xDEFF
+ */
+
+#define GUC_RELAY_ACTION_DEBUG_ONLY_START	0xDEB0
+#define GUC_RELAY_ACTION_DEBUG_ONLY_END		0xDEFF
+
+/**
+ * DOC: VFXPF_TESTLOOP
+ *
+ * This `Relay Message`_ is used to selftest the `GuC Relay Communication`_.
+ *
+ * The following opcodes are defined:
+ * VFXPF_TESTLOOP_OPCODE_NOP_ will return no data.
+ * VFXPF_TESTLOOP_OPCODE_BUSY_ will reply with BUSY response first.
+ * VFXPF_TESTLOOP_OPCODE_RETRY_ will reply with RETRY response instead.
+ * VFXPF_TESTLOOP_OPCODE_ECHO_ will return same data as received.
+ * VFXPF_TESTLOOP_OPCODE_FAIL_ will always fail with error.
+ *
+ *  +---+-------+--------------------------------------------------------------+
+ *  |   | Bits  | Description                                                  |
+ *  +===+=======+==============================================================+
+ *  | 0 |    31 | ORIGIN = GUC_HXG_ORIGIN_HOST_                                |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 30:28 | TYPE = GUC_HXG_TYPE_REQUEST_ or GUC_HXG_TYPE_FAST_REQUEST_   |
+ *  |   |       | or GUC_HXG_TYPE_EVENT_                                       |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 27:16 | **OPCODE**                                                   |
+ *  |   |       |    - _`VFXPF_TESTLOOP_OPCODE_NOP` = 0x0                      |
+ *  |   |       |    - _`VFXPF_TESTLOOP_OPCODE_BUSY` = 0xB                     |
+ *  |   |       |    - _`VFXPF_TESTLOOP_OPCODE_RETRY` = 0xD                    |
+ *  |   |       |    - _`VFXPF_TESTLOOP_OPCODE_ECHO` = 0xE                     |
+ *  |   |       |    - _`VFXPF_TESTLOOP_OPCODE_FAIL` = 0xF                     |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   |  15:0 | ACTION = _`IOV_ACTION_SELFTEST_RELAY`                        |
+ *  +---+-------+--------------------------------------------------------------+
+ *  | 1 |  31:0 | **DATA1** = optional, depends on **OPCODE**:                 |
+ *  |   |       | for VFXPF_TESTLOOP_OPCODE_BUSY_: time in ms for reply        |
+ *  |   |       | for VFXPF_TESTLOOP_OPCODE_FAIL_: expected error              |
+ *  |   |       | for VFXPF_TESTLOOP_OPCODE_ECHO_: payload                     |
+ *  +---+-------+--------------------------------------------------------------+
+ *  |...|  31:0 | **DATAn** = only for **OPCODE** VFXPF_TESTLOOP_OPCODE_ECHO_  |
+ *  +---+-------+--------------------------------------------------------------+
+ *
+ *  +---+-------+--------------------------------------------------------------+
+ *  |   | Bits  | Description                                                  |
+ *  +===+=======+==============================================================+
+ *  | 0 |    31 | ORIGIN = GUC_HXG_ORIGIN_HOST_                                |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   | 30:28 | TYPE = GUC_HXG_TYPE_RESPONSE_SUCCESS_                        |
+ *  |   +-------+--------------------------------------------------------------+
+ *  |   |  27:0 | DATA0 = MBZ                                                  |
+ *  +---+-------+--------------------------------------------------------------+
+ *  |...|  31:0 | DATAn = only for **OPCODE** VFXPF_TESTLOOP_OPCODE_ECHO_      |
+ *  +---+-------+--------------------------------------------------------------+
+ */
+#define GUC_RELAY_ACTION_VFXPF_TESTLOOP		(GUC_RELAY_ACTION_DEBUG_ONLY_START + 1)
+#define   VFXPF_TESTLOOP_OPCODE_NOP		0x0
+#define   VFXPF_TESTLOOP_OPCODE_BUSY		0xB
+#define   VFXPF_TESTLOOP_OPCODE_RETRY		0xD
+#define   VFXPF_TESTLOOP_OPCODE_ECHO		0xE
+#define   VFXPF_TESTLOOP_OPCODE_FAIL		0xF
+
+#endif
diff --git a/drivers/gpu/drm/xe/abi/guc_relay_communication_abi.h b/drivers/gpu/drm/xe/abi/guc_relay_communication_abi.h
new file mode 100644
index 000000000..f92625f04
--- /dev/null
+++ b/drivers/gpu/drm/xe/abi/guc_relay_communication_abi.h
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2023 Intel Corporation
+ */
+
+#ifndef _ABI_GUC_RELAY_COMMUNICATION_ABI_H
+#define _ABI_GUC_RELAY_COMMUNICATION_ABI_H
+
+#include <linux/build_bug.h>
+
+#include "guc_actions_sriov_abi.h"
+#include "guc_communication_ctb_abi.h"
+#include "guc_messages_abi.h"
+
+/**
+ * DOC: GuC Relay Communication
+ *
+ * The communication between Virtual Function (VF) drivers and Physical Function
+ * (PF) drivers is based on the GuC firmware acting as a proxy (relay) agent.
+ *
+ * To communicate with the PF driver, VF's drivers use `VF2GUC_RELAY_TO_PF`_
+ * action that takes the `Relay Message`_ as opaque payload and requires the
+ * relay message identifier (RID) as additional parameter.
+ *
+ * This identifier is used by the drivers to match related messages.
+ *
+ * The GuC forwards this `Relay Message`_ and its identifier to the PF driver
+ * in `GUC2PF_RELAY_FROM_VF`_ action. This event message additionally contains
+ * the identifier of the origin VF (VFID).
+ *
+ * Likewise, to communicate with the VF drivers, PF driver use
+ * `VF2GUC_RELAY_TO_PF`_ action that in addition to the `Relay Message`_
+ * and the relay message identifier (RID) also takes the target VF identifier.
+ *
+ * The GuC uses this target VFID from the message to select where to send the
+ * `GUC2VF_RELAY_FROM_PF`_ with the embedded `Relay Message`_ with response::
+ *
+ *      VF                             GuC                              PF
+ *      |                               |                               |
+ *     [ ] VF2GUC_RELAY_TO_PF           |                               |
+ *     [ ]---------------------------> [ ]                              |
+ *     [ ] { rid, msg }                [ ]                              |
+ *     [ ]                             [ ] GUC2PF_RELAY_FROM_VF         |
+ *     [ ]                             [ ]---------------------------> [ ]
+ *     [ ]                              |  { VFID, rid, msg }          [ ]
+ *     [ ]                              |                              [ ]
+ *     [ ]                              |           PF2GUC_RELAY_TO_VF [ ]
+ *     [ ]                             [ ] <---------------------------[ ]
+ *     [ ]                             [ ]        { VFID, rid, reply }  |
+ *     [ ]        GUC2VF_RELAY_FROM_PF [ ]                              |
+ *     [ ] <---------------------------[ ]                              |
+ *      |               { rid, reply }  |                               |
+ *      |                               |                               |
+ *
+ * It is also possible that PF driver will initiate communication with the
+ * selected VF driver. The same GuC action messages will be used::
+ *
+ *      VF                             GuC                              PF
+ *      |                               |                               |
+ *      |                               |           PF2GUC_RELAY_TO_VF [ ]
+ *      |                              [ ] <---------------------------[ ]
+ *      |                              [ ]          { VFID, rid, msg } [ ]
+ *      |         GUC2VF_RELAY_FROM_PF [ ]                             [ ]
+ *     [ ] <---------------------------[ ]                             [ ]
+ *     [ ]                { rid, msg }  |                              [ ]
+ *     [ ]                              |                              [ ]
+ *     [ ] VF2GUC_RELAY_TO_PF           |                              [ ]
+ *     [ ]---------------------------> [ ]                             [ ]
+ *      |  { rid, reply }              [ ]                             [ ]
+ *      |                              [ ] GUC2PF_RELAY_FROM_VF        [ ]
+ *      |                              [ ]---------------------------> [ ]
+ *      |                               | { VFID, rid, reply }          |
+ *      |                               |                               |
+ */
+
+/**
+ * DOC: Relay Message
+ *
+ * The `Relay Message`_ is used by Physical Function (PF) driver and Virtual
+ * Function (VF) drivers to communicate using `GuC Relay Communication`_.
+ *
+ * Format of the `Relay Message`_ follows format of the generic `HXG Message`_.
+ *
+ *  +--------------------------------------------------------------------------+
+ *  |  `Relay Message`_                                                        |
+ *  +==========================================================================+
+ *  |  `HXG Message`_                                                          |
+ *  +--------------------------------------------------------------------------+
+ *
+ * Maximum length of the `Relay Message`_ is limited by the maximum length of
+ * the `CTB HXG Message`_ and format of the `GUC2PF_RELAY_FROM_VF`_ message.
+ */
+
+#define GUC_RELAY_MSG_MIN_LEN GUC_HXG_MSG_MIN_LEN
+#define GUC_RELAY_MSG_MAX_LEN \
+	(GUC_CTB_MAX_DWORDS - GUC2PF_RELAY_FROM_VF_EVENT_MSG_MIN_LEN)
+
+static_assert(PF2GUC_RELAY_TO_VF_REQUEST_MSG_MIN_LEN >
+	      VF2GUC_RELAY_TO_PF_REQUEST_MSG_MIN_LEN);
+
+/**
+ * DOC: Relay Error Codes
+ *
+ * The `GuC Relay Communication`_ can be used to pass `Relay Message`_ between
+ * drivers that run on different Operating Systems. To help in troubleshooting,
+ * `GuC Relay Communication`_ uses error codes that mostly match errno values.
+ */
+
+#define GUC_RELAY_ERROR_UNDISCLOSED			0
+#define GUC_RELAY_ERROR_OPERATION_NOT_PERMITTED		1	/* EPERM */
+#define GUC_RELAY_ERROR_PERMISSION_DENIED		13	/* EACCES */
+#define GUC_RELAY_ERROR_INVALID_ARGUMENT		22	/* EINVAL */
+#define GUC_RELAY_ERROR_INVALID_REQUEST_CODE		56	/* EBADRQC */
+#define GUC_RELAY_ERROR_NO_DATA_AVAILABLE		61	/* ENODATA */
+#define GUC_RELAY_ERROR_PROTOCOL_ERROR			71	/* EPROTO */
+#define GUC_RELAY_ERROR_MESSAGE_SIZE			90	/* EMSGSIZE */
+
+#endif