1 /*
2 * Copyright (c) 2016 Intel Corporation.
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <logging/log.h>
8 LOG_MODULE_REGISTER(net_ieee802154_csma, CONFIG_NET_L2_IEEE802154_LOG_LEVEL);
9
10 #include <net/net_core.h>
11 #include <net/net_if.h>
12
13 #include <sys/util.h>
14 #include <random/rand32.h>
15
16 #include <stdlib.h>
17 #include <errno.h>
18
19 #include "ieee802154_frame.h"
20 #include "ieee802154_utils.h"
21 #include "ieee802154_radio_utils.h"
22
csma_ca_radio_send(struct net_if * iface,struct net_pkt * pkt,struct net_buf * frag)23 static inline int csma_ca_radio_send(struct net_if *iface,
24 struct net_pkt *pkt,
25 struct net_buf *frag)
26 {
27 const uint8_t max_bo = CONFIG_NET_L2_IEEE802154_RADIO_CSMA_CA_MAX_BO;
28 const uint8_t max_be = CONFIG_NET_L2_IEEE802154_RADIO_CSMA_CA_MAX_BE;
29 uint8_t retries = CONFIG_NET_L2_IEEE802154_RADIO_TX_RETRIES;
30 struct ieee802154_context *ctx = net_if_l2_data(iface);
31 bool ack_required = prepare_for_ack(ctx, pkt, frag);
32 uint8_t be = CONFIG_NET_L2_IEEE802154_RADIO_CSMA_CA_MIN_BE;
33 uint8_t nb = 0U;
34 int ret = -EIO;
35
36 NET_DBG("frag %p", frag);
37
38 loop:
39 while (retries) {
40 retries--;
41
42 if (be) {
43 uint8_t bo_n = sys_rand32_get() & ((1 << be) - 1);
44
45 k_busy_wait(bo_n * 20U);
46 }
47
48 while (1) {
49 if (!ieee802154_cca(iface)) {
50 break;
51 }
52
53 be = MIN(be + 1, max_be);
54 nb++;
55
56 if (nb > max_bo) {
57 goto loop;
58 }
59 }
60
61 ret = ieee802154_tx(iface, IEEE802154_TX_MODE_DIRECT,
62 pkt, frag);
63 if (ret) {
64 continue;
65 }
66
67 ret = wait_for_ack(iface, ack_required);
68 if (!ret) {
69 break;
70 }
71 }
72
73 return ret;
74 }
75
csma_ca_radio_handle_ack(struct net_if * iface,struct net_pkt * pkt)76 static enum net_verdict csma_ca_radio_handle_ack(struct net_if *iface,
77 struct net_pkt *pkt)
78 {
79 struct ieee802154_context *ctx = net_if_l2_data(iface);
80
81 if (IS_ENABLED(CONFIG_NET_L2_IEEE802154_RADIO_CSMA_CA) &&
82 ieee802154_get_hw_capabilities(iface) & IEEE802154_HW_CSMA) {
83 return NET_OK;
84 }
85
86 return handle_ack(ctx, pkt);
87 }
88
89 /* Declare the public Radio driver function used by the HW drivers */
90 FUNC_ALIAS(csma_ca_radio_send,
91 ieee802154_radio_send, int);
92
93 FUNC_ALIAS(csma_ca_radio_handle_ack,
94 ieee802154_radio_handle_ack, enum net_verdict);
95
