1/* SPDX-License-Identifier: BSD-3-Clause
2 * Copyright 2008-2017 Cisco Systems, Inc.  All rights reserved.
3 * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
4 */
5
6#ifndef _CQ_DESC_H_
7#define _CQ_DESC_H_
8
9/*
10 * Completion queue descriptor types
11 */
12enum cq_desc_types {
13	CQ_DESC_TYPE_WQ_ENET = 0,
14	CQ_DESC_TYPE_DESC_COPY = 1,
15	CQ_DESC_TYPE_WQ_EXCH = 2,
16	CQ_DESC_TYPE_RQ_ENET = 3,
17	CQ_DESC_TYPE_RQ_FCP = 4,
18	CQ_DESC_TYPE_IOMMU_MISS = 5,
19	CQ_DESC_TYPE_SGL = 6,
20	CQ_DESC_TYPE_CLASSIFIER = 7,
21	CQ_DESC_TYPE_TEST = 127,
22};
23
24/* Completion queue descriptor: 16B
25 *
26 * All completion queues have this basic layout.  The
27 * type_specfic area is unique for each completion
28 * queue type.
29 */
30struct cq_desc {
31	__le16 completed_index;
32	__le16 q_number;
33	u8 type_specfic[11];
34	u8 type_color;
35};
36
37#define CQ_DESC_TYPE_BITS        4
38#define CQ_DESC_TYPE_MASK        ((1 << CQ_DESC_TYPE_BITS) - 1)
39#define CQ_DESC_COLOR_MASK       1
40#define CQ_DESC_COLOR_SHIFT      7
41#define CQ_DESC_COLOR_MASK_NOSHIFT 0x80
42#define CQ_DESC_Q_NUM_BITS       10
43#define CQ_DESC_Q_NUM_MASK       ((1 << CQ_DESC_Q_NUM_BITS) - 1)
44#define CQ_DESC_COMP_NDX_BITS    12
45#define CQ_DESC_COMP_NDX_MASK    ((1 << CQ_DESC_COMP_NDX_BITS) - 1)
46
47static inline void cq_color_enc(struct cq_desc *desc, const u8 color)
48{
49	if (color)
50		desc->type_color |=  (1 << CQ_DESC_COLOR_SHIFT);
51	else
52		desc->type_color &= ~(1 << CQ_DESC_COLOR_SHIFT);
53}
54
55static inline void cq_desc_enc(struct cq_desc *desc,
56	const u8 type, const u8 color, const u16 q_number,
57	const u16 completed_index)
58{
59	desc->type_color = (type & CQ_DESC_TYPE_MASK) |
60		((color & CQ_DESC_COLOR_MASK) << CQ_DESC_COLOR_SHIFT);
61	desc->q_number = cpu_to_le16(q_number & CQ_DESC_Q_NUM_MASK);
62	desc->completed_index = cpu_to_le16(completed_index &
63		CQ_DESC_COMP_NDX_MASK);
64}
65
66static inline void cq_desc_dec(const struct cq_desc *desc_arg,
67	u8 *type, u8 *color, u16 *q_number, u16 *completed_index)
68{
69	const struct cq_desc *desc = desc_arg;
70	const u8 type_color = desc->type_color;
71
72	*color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;
73
74	/*
75	 * Make sure color bit is read from desc *before* other fields
76	 * are read from desc.  Hardware guarantees color bit is last
77	 * bit (byte) written.  Adding the rmb() prevents the compiler
78	 * and/or CPU from reordering the reads which would potentially
79	 * result in reading stale values.
80	 */
81
82	rmb();
83
84	*type = type_color & CQ_DESC_TYPE_MASK;
85	*q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;
86	*completed_index = le16_to_cpu(desc->completed_index) &
87		CQ_DESC_COMP_NDX_MASK;
88}
89
90static inline void cq_color_dec(const struct cq_desc *desc_arg, u8 *color)
91{
92	volatile const struct cq_desc *desc = desc_arg;
93
94	*color = (desc->type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;
95}
96
97#endif /* _CQ_DESC_H_ */
98