1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
new file mode 100644
index 000000000000..d38935f47ecf
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2014-2021 Intel Corporation
+ */
+
+#ifndef _ABI_GUC_COMMUNICATION_CTB_ABI_H
+#define _ABI_GUC_COMMUNICATION_CTB_ABI_H
+
+#include <linux/types.h>
+
+/**
+ * DOC: CTB based communication
+ *
+ * The CTB (command transport buffer) communication between Host and GuC
+ * is based on u32 data stream written to the shared buffer. One buffer can
+ * be used to transmit data only in one direction (one-directional channel).
+ *
+ * Current status of the each buffer is stored in the buffer descriptor.
+ * Buffer descriptor holds tail and head fields that represents active data
+ * stream. The tail field is updated by the data producer (sender), and head
+ * field is updated by the data consumer (receiver)::
+ *
+ *      +------------+
+ *      | DESCRIPTOR |          +=================+============+========+
+ *      +============+          |                 | MESSAGE(s) |        |
+ *      | address    |--------->+=================+============+========+
+ *      +------------+
+ *      | head       |          ^-----head--------^
+ *      +------------+
+ *      | tail       |          ^---------tail-----------------^
+ *      +------------+
+ *      | size       |          ^---------------size--------------------^
+ *      +------------+
+ *
+ * Each message in data stream starts with the single u32 treated as a header,
+ * followed by optional set of u32 data that makes message specific payload::
+ *
+ *      +------------+---------+---------+---------+
+ *      |         MESSAGE                          |
+ *      +------------+---------+---------+---------+
+ *      |   msg[0]   |   [1]   |   ...   |  [n-1]  |
+ *      +------------+---------+---------+---------+
+ *      |   MESSAGE  |       MESSAGE PAYLOAD       |
+ *      +   HEADER   +---------+---------+---------+
+ *      |            |    0    |   ...   |    n    |
+ *      +======+=====+=========+=========+=========+
+ *      | 31:16| code|         |         |         |
+ *      +------+-----+         |         |         |
+ *      |  15:5|flags|         |         |         |
+ *      +------+-----+         |         |         |
+ *      |   4:0|  len|         |         |         |
+ *      +------+-----+---------+---------+---------+
+ *
+ *                   ^-------------len-------------^
+ *
+ * The message header consists of:
+ *
+ * - **len**, indicates length of the message payload (in u32)
+ * - **code**, indicates message code
+ * - **flags**, holds various bits to control message handling
+ */
+
+/*
+ * Describes single command transport buffer.
+ * Used by both guc-master and clients.
+ */
+struct guc_ct_buffer_desc {
+	u32 addr;		/* gfx address */
+	u64 host_private;	/* host private data */
+	u32 size;		/* size in bytes */
+	u32 head;		/* offset updated by GuC*/
+	u32 tail;		/* offset updated by owner */
+	u32 is_in_error;	/* error indicator */
+	u32 reserved1;
+	u32 reserved2;
+	u32 owner;		/* id of the channel owner */
+	u32 owner_sub_id;	/* owner-defined field for extra tracking */
+	u32 reserved[5];
+} __packed;
+
+/* Type of command transport buffer */
+#define INTEL_GUC_CT_BUFFER_TYPE_SEND	0x0u
+#define INTEL_GUC_CT_BUFFER_TYPE_RECV	0x1u
+
+/*
+ * Definition of the command transport message header (DW0)
+ *
+ * bit[4..0]	message len (in dwords)
+ * bit[7..5]	reserved
+ * bit[8]	response (G2H only)
+ * bit[8]	write fence to desc (H2G only)
+ * bit[9]	write status to H2G buff (H2G only)
+ * bit[10]	send status back via G2H (H2G only)
+ * bit[15..11]	reserved
+ * bit[31..16]	action code
+ */
+#define GUC_CT_MSG_LEN_SHIFT			0
+#define GUC_CT_MSG_LEN_MASK			0x1F
+#define GUC_CT_MSG_IS_RESPONSE			(1 << 8)
+#define GUC_CT_MSG_WRITE_FENCE_TO_DESC		(1 << 8)
+#define GUC_CT_MSG_WRITE_STATUS_TO_BUFF		(1 << 9)
+#define GUC_CT_MSG_SEND_STATUS			(1 << 10)
+#define GUC_CT_MSG_ACTION_SHIFT			16
+#define GUC_CT_MSG_ACTION_MASK			0xFFFF
+
+#endif /* _ABI_GUC_COMMUNICATION_CTB_ABI_H */