1 /* SPDX-License-Identifier: MIT */
2 /* Copyright (C) 2006-2017 Oracle Corporation */
3 
4 #ifndef __HGSMI_DEFS_H__
5 #define __HGSMI_DEFS_H__
6 
7 /* Buffer sequence type mask. */
8 #define HGSMI_BUFFER_HEADER_F_SEQ_MASK     0x03
9 /* Single buffer, not a part of a sequence. */
10 #define HGSMI_BUFFER_HEADER_F_SEQ_SINGLE   0x00
11 /* The first buffer in a sequence. */
12 #define HGSMI_BUFFER_HEADER_F_SEQ_START    0x01
13 /* A middle buffer in a sequence. */
14 #define HGSMI_BUFFER_HEADER_F_SEQ_CONTINUE 0x02
15 /* The last buffer in a sequence. */
16 #define HGSMI_BUFFER_HEADER_F_SEQ_END      0x03
17 
18 /* 16 bytes buffer header. */
19 struct hgsmi_buffer_header {
20 	u32 data_size;		/* Size of data that follows the header. */
21 	u8 flags;		/* HGSMI_BUFFER_HEADER_F_* */
22 	u8 channel;		/* The channel the data must be routed to. */
23 	u16 channel_info;	/* Opaque to the HGSMI, used by the channel. */
24 
25 	union {
26 		/* Opaque placeholder to make the union 8 bytes. */
27 		u8 header_data[8];
28 
29 		/* HGSMI_BUFFER_HEADER_F_SEQ_SINGLE */
30 		struct {
31 			u32 reserved1;	/* A reserved field, initialize to 0. */
32 			u32 reserved2;	/* A reserved field, initialize to 0. */
33 		} buffer;
34 
35 		/* HGSMI_BUFFER_HEADER_F_SEQ_START */
36 		struct {
37 			/* Must be the same for all buffers in the sequence. */
38 			u32 sequence_number;
39 			/* The total size of the sequence. */
40 			u32 sequence_size;
41 		} sequence_start;
42 
43 		/*
44 		 * HGSMI_BUFFER_HEADER_F_SEQ_CONTINUE and
45 		 * HGSMI_BUFFER_HEADER_F_SEQ_END
46 		 */
47 		struct {
48 			/* Must be the same for all buffers in the sequence. */
49 			u32 sequence_number;
50 			/* Data offset in the entire sequence. */
51 			u32 sequence_offset;
52 		} sequence_continue;
53 	} u;
54 } __packed;
55 
56 /* 8 bytes buffer tail. */
57 struct hgsmi_buffer_tail {
58 	/* Reserved, must be initialized to 0. */
59 	u32 reserved;
60 	/*
61 	 * One-at-a-Time Hash: https://www.burtleburtle.net/bob/hash/doobs.html
62 	 * Over the header, offset and for first 4 bytes of the tail.
63 	 */
64 	u32 checksum;
65 } __packed;
66 
67 /*
68  * The size of the array of channels. Array indexes are u8.
69  * Note: the value must not be changed.
70  */
71 #define HGSMI_NUMBER_OF_CHANNELS 0x100
72 
73 #endif
74