1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* Copyright (C) 2024 Intel Corporation */
3
4 #ifndef __LIBETH_TX_H
5 #define __LIBETH_TX_H
6
7 #include <linux/skbuff.h>
8
9 #include <net/libeth/types.h>
10
11 /* Tx buffer completion */
12
13 /**
14 * enum libeth_sqe_type - type of &libeth_sqe to act on Tx completion
15 * @LIBETH_SQE_EMPTY: unused/empty, no action required
16 * @LIBETH_SQE_CTX: context descriptor with empty SQE, no action required
17 * @LIBETH_SQE_SLAB: kmalloc-allocated buffer, unmap and kfree()
18 * @LIBETH_SQE_FRAG: mapped skb frag, only unmap DMA
19 * @LIBETH_SQE_SKB: &sk_buff, unmap and napi_consume_skb(), update stats
20 */
21 enum libeth_sqe_type {
22 LIBETH_SQE_EMPTY = 0U,
23 LIBETH_SQE_CTX,
24 LIBETH_SQE_SLAB,
25 LIBETH_SQE_FRAG,
26 LIBETH_SQE_SKB,
27 };
28
29 /**
30 * struct libeth_sqe - represents a Send Queue Element / Tx buffer
31 * @type: type of the buffer, see the enum above
32 * @rs_idx: index of the last buffer from the batch this one was sent in
33 * @raw: slab buffer to free via kfree()
34 * @skb: &sk_buff to consume
35 * @dma: DMA address to unmap
36 * @len: length of the mapped region to unmap
37 * @nr_frags: number of frags in the frame this buffer belongs to
38 * @packets: number of physical packets sent for this frame
39 * @bytes: number of physical bytes sent for this frame
40 * @priv: driver-private scratchpad
41 */
42 struct libeth_sqe {
43 enum libeth_sqe_type type:32;
44 u32 rs_idx;
45
46 union {
47 void *raw;
48 struct sk_buff *skb;
49 };
50
51 DEFINE_DMA_UNMAP_ADDR(dma);
52 DEFINE_DMA_UNMAP_LEN(len);
53
54 u32 nr_frags;
55 u32 packets;
56 u32 bytes;
57
58 unsigned long priv;
59 } __aligned_largest;
60
61 /**
62 * LIBETH_SQE_CHECK_PRIV - check the driver's private SQE data
63 * @p: type or name of the object the driver wants to fit into &libeth_sqe
64 *
65 * Make sure the driver's private data fits into libeth_sqe::priv. To be used
66 * right after its declaration.
67 */
68 #define LIBETH_SQE_CHECK_PRIV(p) \
69 static_assert(sizeof(p) <= sizeof_field(struct libeth_sqe, priv))
70
71 /**
72 * struct libeth_cq_pp - completion queue poll params
73 * @dev: &device to perform DMA unmapping
74 * @ss: onstack NAPI stats to fill
75 * @napi: whether it's called from the NAPI context
76 *
77 * libeth uses this structure to access objects needed for performing full
78 * Tx complete operation without passing lots of arguments and change the
79 * prototypes each time a new one is added.
80 */
81 struct libeth_cq_pp {
82 struct device *dev;
83 struct libeth_sq_napi_stats *ss;
84
85 bool napi;
86 };
87
88 /**
89 * libeth_tx_complete - perform Tx completion for one SQE
90 * @sqe: SQE to complete
91 * @cp: poll params
92 *
93 * Do Tx complete for all the types of buffers, incl. freeing, unmapping,
94 * updating the stats etc.
95 */
96 static inline void libeth_tx_complete(struct libeth_sqe *sqe,
97 const struct libeth_cq_pp *cp)
98 {
99 switch (sqe->type) {
100 case LIBETH_SQE_EMPTY:
101 return;
102 case LIBETH_SQE_SKB:
103 case LIBETH_SQE_FRAG:
104 case LIBETH_SQE_SLAB:
105 dma_unmap_page(cp->dev, dma_unmap_addr(sqe, dma),
106 dma_unmap_len(sqe, len), DMA_TO_DEVICE);
107 break;
108 default:
109 break;
110 }
111
112 switch (sqe->type) {
113 case LIBETH_SQE_SKB:
114 cp->ss->packets += sqe->packets;
115 cp->ss->bytes += sqe->bytes;
116
117 napi_consume_skb(sqe->skb, cp->napi);
118 break;
119 case LIBETH_SQE_SLAB:
120 kfree(sqe->raw);
121 break;
122 default:
123 break;
124 }
125
126 sqe->type = LIBETH_SQE_EMPTY;
127 }
128
129 #endif /* __LIBETH_TX_H */
130
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