1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /* Copyright (c) 2019 Mellanox Technologies. */
3 
4 #include "en/params.h"
5 
6 static inline bool mlx5e_rx_is_xdp(struct mlx5e_params *params,
7 				   struct mlx5e_xsk_param *xsk)
8 {
9 	return params->xdp_prog || xsk;
10 }
11 
12 u16 mlx5e_get_linear_rq_headroom(struct mlx5e_params *params,
13 				 struct mlx5e_xsk_param *xsk)
14 {
15 	u16 headroom = NET_IP_ALIGN;
16 
17 	if (mlx5e_rx_is_xdp(params, xsk)) {
18 		headroom += XDP_PACKET_HEADROOM;
19 		if (xsk)
20 			headroom += xsk->headroom;
21 	} else {
22 		headroom += MLX5_RX_HEADROOM;
23 	}
24 
25 	return headroom;
26 }
27 
28 u32 mlx5e_rx_get_min_frag_sz(struct mlx5e_params *params,
29 			     struct mlx5e_xsk_param *xsk)
30 {
31 	u32 hw_mtu = MLX5E_SW2HW_MTU(params, params->sw_mtu);
32 	u16 linear_rq_headroom = mlx5e_get_linear_rq_headroom(params, xsk);
33 
34 	return linear_rq_headroom + hw_mtu;
35 }
36 
37 u32 mlx5e_rx_get_linear_frag_sz(struct mlx5e_params *params,
38 				struct mlx5e_xsk_param *xsk)
39 {
40 	u32 frag_sz = mlx5e_rx_get_min_frag_sz(params, xsk);
41 
42 	/* AF_XDP doesn't build SKBs in place. */
43 	if (!xsk)
44 		frag_sz = MLX5_SKB_FRAG_SZ(frag_sz);
45 
46 	/* XDP in mlx5e doesn't support multiple packets per page. AF_XDP is a
47 	 * special case. It can run with frames smaller than a page, as it
48 	 * doesn't allocate pages dynamically. However, here we pretend that
49 	 * fragments are page-sized: it allows to treat XSK frames like pages
50 	 * by redirecting alloc and free operations to XSK rings and by using
51 	 * the fact there are no multiple packets per "page" (which is a frame).
52 	 * The latter is important, because frames may come in a random order,
53 	 * and we will have trouble assemblying a real page of multiple frames.
54 	 */
55 	if (mlx5e_rx_is_xdp(params, xsk))
56 		frag_sz = max_t(u32, frag_sz, PAGE_SIZE);
57 
58 	/* Even if we can go with a smaller fragment size, we must not put
59 	 * multiple packets into a single frame.
60 	 */
61 	if (xsk)
62 		frag_sz = max_t(u32, frag_sz, xsk->chunk_size);
63 
64 	return frag_sz;
65 }
66 
67 u8 mlx5e_mpwqe_log_pkts_per_wqe(struct mlx5e_params *params,
68 				struct mlx5e_xsk_param *xsk)
69 {
70 	u32 linear_frag_sz = mlx5e_rx_get_linear_frag_sz(params, xsk);
71 
72 	return MLX5_MPWRQ_LOG_WQE_SZ - order_base_2(linear_frag_sz);
73 }
74 
75 bool mlx5e_rx_is_linear_skb(struct mlx5e_params *params,
76 			    struct mlx5e_xsk_param *xsk)
77 {
78 	/* AF_XDP allocates SKBs on XDP_PASS - ensure they don't occupy more
79 	 * than one page. For this, check both with and without xsk.
80 	 */
81 	u32 linear_frag_sz = max(mlx5e_rx_get_linear_frag_sz(params, xsk),
82 				 mlx5e_rx_get_linear_frag_sz(params, NULL));
83 
84 	return !params->lro_en && linear_frag_sz <= PAGE_SIZE;
85 }
86 
87 #define MLX5_MAX_MPWQE_LOG_WQE_STRIDE_SZ ((BIT(__mlx5_bit_sz(wq, log_wqe_stride_size)) - 1) + \
88 					  MLX5_MPWQE_LOG_STRIDE_SZ_BASE)
89 bool mlx5e_rx_mpwqe_is_linear_skb(struct mlx5_core_dev *mdev,
90 				  struct mlx5e_params *params,
91 				  struct mlx5e_xsk_param *xsk)
92 {
93 	u32 linear_frag_sz = mlx5e_rx_get_linear_frag_sz(params, xsk);
94 	s8 signed_log_num_strides_param;
95 	u8 log_num_strides;
96 
97 	if (!mlx5e_rx_is_linear_skb(params, xsk))
98 		return false;
99 
100 	if (order_base_2(linear_frag_sz) > MLX5_MAX_MPWQE_LOG_WQE_STRIDE_SZ)
101 		return false;
102 
103 	if (MLX5_CAP_GEN(mdev, ext_stride_num_range))
104 		return true;
105 
106 	log_num_strides = MLX5_MPWRQ_LOG_WQE_SZ - order_base_2(linear_frag_sz);
107 	signed_log_num_strides_param =
108 		(s8)log_num_strides - MLX5_MPWQE_LOG_NUM_STRIDES_BASE;
109 
110 	return signed_log_num_strides_param >= 0;
111 }
112 
113 u8 mlx5e_mpwqe_get_log_rq_size(struct mlx5e_params *params,
114 			       struct mlx5e_xsk_param *xsk)
115 {
116 	u8 log_pkts_per_wqe = mlx5e_mpwqe_log_pkts_per_wqe(params, xsk);
117 
118 	/* Numbers are unsigned, don't subtract to avoid underflow. */
119 	if (params->log_rq_mtu_frames <
120 	    log_pkts_per_wqe + MLX5E_PARAMS_MINIMUM_LOG_RQ_SIZE_MPW)
121 		return MLX5E_PARAMS_MINIMUM_LOG_RQ_SIZE_MPW;
122 
123 	return params->log_rq_mtu_frames - log_pkts_per_wqe;
124 }
125 
126 u8 mlx5e_mpwqe_get_log_stride_size(struct mlx5_core_dev *mdev,
127 				   struct mlx5e_params *params,
128 				   struct mlx5e_xsk_param *xsk)
129 {
130 	if (mlx5e_rx_mpwqe_is_linear_skb(mdev, params, xsk))
131 		return order_base_2(mlx5e_rx_get_linear_frag_sz(params, xsk));
132 
133 	return MLX5_MPWRQ_DEF_LOG_STRIDE_SZ(mdev);
134 }
135 
136 u8 mlx5e_mpwqe_get_log_num_strides(struct mlx5_core_dev *mdev,
137 				   struct mlx5e_params *params,
138 				   struct mlx5e_xsk_param *xsk)
139 {
140 	return MLX5_MPWRQ_LOG_WQE_SZ -
141 		mlx5e_mpwqe_get_log_stride_size(mdev, params, xsk);
142 }
143 
144 u16 mlx5e_get_rq_headroom(struct mlx5_core_dev *mdev,
145 			  struct mlx5e_params *params,
146 			  struct mlx5e_xsk_param *xsk)
147 {
148 	bool is_linear_skb = (params->rq_wq_type == MLX5_WQ_TYPE_CYCLIC) ?
149 		mlx5e_rx_is_linear_skb(params, xsk) :
150 		mlx5e_rx_mpwqe_is_linear_skb(mdev, params, xsk);
151 
152 	return is_linear_skb ? mlx5e_get_linear_rq_headroom(params, xsk) : 0;
153 }
154