1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * Copyright 2008-2010 Cisco Systems, Inc.  All rights reserved.
 4 * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
 5 */
 6
 7#ifndef _CQ_DESC_H_
 8#define _CQ_DESC_H_
 9
10/*
11 * Completion queue descriptor types
12 */
13enum cq_desc_types {
14	CQ_DESC_TYPE_WQ_ENET = 0,
15	CQ_DESC_TYPE_DESC_COPY = 1,
16	CQ_DESC_TYPE_WQ_EXCH = 2,
17	CQ_DESC_TYPE_RQ_ENET = 3,
18	CQ_DESC_TYPE_RQ_FCP = 4,
19};
20
21/* Completion queue descriptor: 16B
22 *
23 * All completion queues have this basic layout.  The
24 * type_specfic area is unique for each completion
25 * queue type.
26 */
27struct cq_desc {
28	__le16 completed_index;
29	__le16 q_number;
30	u8 type_specfic[11];
31	u8 type_color;
32};
33
34#define CQ_DESC_TYPE_BITS        4
35#define CQ_DESC_TYPE_MASK        ((1 << CQ_DESC_TYPE_BITS) - 1)
36#define CQ_DESC_COLOR_MASK       1
37#define CQ_DESC_COLOR_SHIFT      7
38#define CQ_DESC_Q_NUM_BITS       10
39#define CQ_DESC_Q_NUM_MASK       ((1 << CQ_DESC_Q_NUM_BITS) - 1)
40#define CQ_DESC_COMP_NDX_BITS    12
41#define CQ_DESC_COMP_NDX_MASK    ((1 << CQ_DESC_COMP_NDX_BITS) - 1)
42
43static inline void cq_desc_dec(const struct cq_desc *desc_arg,
44	u8 *type, u8 *color, u16 *q_number, u16 *completed_index)
45{
46	const struct cq_desc *desc = desc_arg;
47	const u8 type_color = desc->type_color;
48
49	*color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;
50
51	/*
52	 * Make sure color bit is read from desc *before* other fields
53	 * are read from desc.  Hardware guarantees color bit is last
54	 * bit (byte) written.  Adding the rmb() prevents the compiler
55	 * and/or CPU from reordering the reads which would potentially
56	 * result in reading stale values.
57	 */
58
59	rmb();
60
61	*type = type_color & CQ_DESC_TYPE_MASK;
62	*q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;
63	*completed_index = le16_to_cpu(desc->completed_index) &
64		CQ_DESC_COMP_NDX_MASK;
65}
66
67#endif /* _CQ_DESC_H_ */

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/*
 3 * Copyright 2008-2010 Cisco Systems, Inc.  All rights reserved.
 4 * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
 5 */
 6
 7#ifndef _CQ_DESC_H_
 8#define _CQ_DESC_H_
 9
10/*
11 * Completion queue descriptor types
12 */
13enum cq_desc_types {
14	CQ_DESC_TYPE_WQ_ENET = 0,
15	CQ_DESC_TYPE_DESC_COPY = 1,
16	CQ_DESC_TYPE_WQ_EXCH = 2,
17	CQ_DESC_TYPE_RQ_ENET = 3,
18	CQ_DESC_TYPE_RQ_FCP = 4,
19};
20
21/* Completion queue descriptor: 16B
22 *
23 * All completion queues have this basic layout.  The
24 * type_specfic area is unique for each completion
25 * queue type.
26 */
27struct cq_desc {
28	__le16 completed_index;
29	__le16 q_number;
30	u8 type_specfic[11];
31	u8 type_color;
32};
33
34#define CQ_DESC_TYPE_BITS        4
35#define CQ_DESC_TYPE_MASK        ((1 << CQ_DESC_TYPE_BITS) - 1)
36#define CQ_DESC_COLOR_MASK       1
37#define CQ_DESC_COLOR_SHIFT      7
38#define CQ_DESC_Q_NUM_BITS       10
39#define CQ_DESC_Q_NUM_MASK       ((1 << CQ_DESC_Q_NUM_BITS) - 1)
40#define CQ_DESC_COMP_NDX_BITS    12
41#define CQ_DESC_COMP_NDX_MASK    ((1 << CQ_DESC_COMP_NDX_BITS) - 1)
42
43static inline void cq_desc_dec(const struct cq_desc *desc_arg,
44	u8 *type, u8 *color, u16 *q_number, u16 *completed_index)
45{
46	const struct cq_desc *desc = desc_arg;
47	const u8 type_color = desc->type_color;
48
49	*color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;
50
51	/*
52	 * Make sure color bit is read from desc *before* other fields
53	 * are read from desc.  Hardware guarantees color bit is last
54	 * bit (byte) written.  Adding the rmb() prevents the compiler
55	 * and/or CPU from reordering the reads which would potentially
56	 * result in reading stale values.
57	 */
58
59	rmb();
60
61	*type = type_color & CQ_DESC_TYPE_MASK;
62	*q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;
63	*completed_index = le16_to_cpu(desc->completed_index) &
64		CQ_DESC_COMP_NDX_MASK;
65}
66
67#endif /* _CQ_DESC_H_ */