xref: /linux/drivers/infiniband/hw/mana/shadow_queue.h (revision 4f9786035f9e519db41375818e1d0b5f20da2f10)
1 /* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
2 /*
3  * Copyright (c) 2024, Microsoft Corporation. All rights reserved.
4  */
5 
6 #ifndef _MANA_SHADOW_QUEUE_H_
7 #define _MANA_SHADOW_QUEUE_H_
8 
9 struct shadow_wqe_header {
10 	u16 opcode;
11 	u16 error_code;
12 	u32 posted_wqe_size;
13 	u64 wr_id;
14 };
15 
16 struct ud_rq_shadow_wqe {
17 	struct shadow_wqe_header header;
18 	u32 byte_len;
19 	u32 src_qpn;
20 };
21 
22 struct ud_sq_shadow_wqe {
23 	struct shadow_wqe_header header;
24 };
25 
26 struct shadow_queue {
27 	/* Unmasked producer index, Incremented on wqe posting */
28 	u64 prod_idx;
29 	/* Unmasked consumer index, Incremented on cq polling */
30 	u64 cons_idx;
31 	/* Unmasked index of next-to-complete (from HW) shadow WQE */
32 	u64 next_to_complete_idx;
33 	/* queue size in wqes */
34 	u32 length;
35 	/* distance between elements in bytes */
36 	u32 stride;
37 	/* ring buffer holding wqes */
38 	void *buffer;
39 };
40 
41 static inline int create_shadow_queue(struct shadow_queue *queue, uint32_t length, uint32_t stride)
42 {
43 	queue->buffer = kvmalloc_array(length, stride, GFP_KERNEL);
44 	if (!queue->buffer)
45 		return -ENOMEM;
46 
47 	queue->length = length;
48 	queue->stride = stride;
49 
50 	return 0;
51 }
52 
53 static inline void destroy_shadow_queue(struct shadow_queue *queue)
54 {
55 	kvfree(queue->buffer);
56 }
57 
58 static inline bool shadow_queue_full(struct shadow_queue *queue)
59 {
60 	return (queue->prod_idx - queue->cons_idx) >= queue->length;
61 }
62 
63 static inline bool shadow_queue_empty(struct shadow_queue *queue)
64 {
65 	return queue->prod_idx == queue->cons_idx;
66 }
67 
68 static inline void *
69 shadow_queue_get_element(const struct shadow_queue *queue, u64 unmasked_index)
70 {
71 	u32 index = unmasked_index % queue->length;
72 
73 	return ((u8 *)queue->buffer + index * queue->stride);
74 }
75 
76 static inline void *
77 shadow_queue_producer_entry(struct shadow_queue *queue)
78 {
79 	return shadow_queue_get_element(queue, queue->prod_idx);
80 }
81 
82 static inline void *
83 shadow_queue_get_next_to_consume(const struct shadow_queue *queue)
84 {
85 	if (queue->cons_idx == queue->next_to_complete_idx)
86 		return NULL;
87 
88 	return shadow_queue_get_element(queue, queue->cons_idx);
89 }
90 
91 static inline void *
92 shadow_queue_get_next_to_complete(struct shadow_queue *queue)
93 {
94 	if (queue->next_to_complete_idx == queue->prod_idx)
95 		return NULL;
96 
97 	return shadow_queue_get_element(queue, queue->next_to_complete_idx);
98 }
99 
100 static inline void shadow_queue_advance_producer(struct shadow_queue *queue)
101 {
102 	queue->prod_idx++;
103 }
104 
105 static inline void shadow_queue_advance_consumer(struct shadow_queue *queue)
106 {
107 	queue->cons_idx++;
108 }
109 
110 static inline void shadow_queue_advance_next_to_complete(struct shadow_queue *queue)
111 {
112 	queue->next_to_complete_idx++;
113 }
114 
115 #endif
116