1 /* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ 2 3 #ifndef _LIBMCTP_H 4 #define _LIBMCTP_H 5 6 #ifdef __cplusplus 7 extern "C" { 8 #endif 9 10 #include <stdarg.h> 11 #include <stdbool.h> 12 #include <stdint.h> 13 #include <stddef.h> 14 15 typedef uint8_t mctp_eid_t; 16 17 /* Special Endpoint ID values */ 18 #define MCTP_EID_NULL 0 19 #define MCTP_EID_BROADCAST 0xff 20 21 /* MCTP packet definitions */ 22 struct mctp_hdr { 23 uint8_t ver; 24 uint8_t dest; 25 uint8_t src; 26 uint8_t flags_seq_tag; 27 }; 28 29 /* Definitions for flags_seq_tag field */ 30 #define MCTP_HDR_FLAG_SOM (1<<7) 31 #define MCTP_HDR_FLAG_EOM (1<<6) 32 #define MCTP_HDR_FLAG_TO (1<<3) 33 #define MCTP_HDR_SEQ_SHIFT (4) 34 #define MCTP_HDR_SEQ_MASK (0x3) 35 #define MCTP_HDR_TAG_SHIFT (0) 36 #define MCTP_HDR_TAG_MASK (0x7) 37 38 /* Baseline Transmission Unit and packet size */ 39 #define MCTP_BTU 64 40 #define MCTP_PACKET_SIZE(unit) ((unit) + sizeof(struct mctp_hdr)) 41 #define MCTP_BODY_SIZE(unit) ((unit) - sizeof(struct mctp_hdr)) 42 43 /* packet buffers */ 44 45 struct mctp_pktbuf { 46 size_t start, end, size; 47 size_t mctp_hdr_off; 48 struct mctp_pktbuf *next; 49 unsigned char data[]; 50 }; 51 52 struct mctp_binding; 53 54 struct mctp_pktbuf *mctp_pktbuf_alloc(struct mctp_binding *hw, size_t len); 55 void mctp_pktbuf_free(struct mctp_pktbuf *pkt); 56 struct mctp_hdr *mctp_pktbuf_hdr(struct mctp_pktbuf *pkt); 57 void *mctp_pktbuf_data(struct mctp_pktbuf *pkt); 58 size_t mctp_pktbuf_size(struct mctp_pktbuf *pkt); 59 void *mctp_pktbuf_alloc_start(struct mctp_pktbuf *pkt, size_t size); 60 void *mctp_pktbuf_alloc_end(struct mctp_pktbuf *pkt, size_t size); 61 int mctp_pktbuf_push(struct mctp_pktbuf *pkt, void *data, size_t len); 62 void *mctp_pktbuf_pop(struct mctp_pktbuf *pkt, size_t len); 63 64 /* MCTP core */ 65 struct mctp; 66 struct mctp_bus; 67 68 struct mctp *mctp_init(void); 69 void mctp_set_max_message_size(struct mctp *mctp, size_t message_size); 70 typedef void (*mctp_capture_fn)(struct mctp_pktbuf *pkt, void *user); 71 void mctp_set_capture_handler(struct mctp *mctp, mctp_capture_fn fn, void *user); 72 void mctp_destroy(struct mctp *mctp); 73 74 /* Register a binding to the MCTP core, and creates a bus (populating 75 * binding->bus). 76 * 77 * If this function is called, the MCTP stack is initialised as an 'endpoint', 78 * and will deliver local packets to a RX callback - see `mctp_set_rx_all()` 79 * below. 80 */ 81 int mctp_register_bus(struct mctp *mctp, 82 struct mctp_binding *binding, 83 mctp_eid_t eid); 84 85 /* Create a simple bidirectional bridge between busses. 86 * 87 * In this mode, the MCTP stack is initialised as a bridge. There is no EID 88 * defined, so no packets are considered local. Instead, all messages from one 89 * binding are forwarded to the other. 90 */ 91 int mctp_bridge_busses(struct mctp *mctp, 92 struct mctp_binding *b1, struct mctp_binding *b2); 93 94 typedef void (*mctp_rx_fn)(uint8_t src_eid, void *data, 95 void *msg, size_t len); 96 97 int mctp_set_rx_all(struct mctp *mctp, mctp_rx_fn fn, void *data); 98 99 int mctp_message_tx(struct mctp *mctp, mctp_eid_t eid, 100 void *msg, size_t msg_len); 101 102 /* hardware bindings */ 103 struct mctp_binding { 104 const char *name; 105 uint8_t version; 106 struct mctp_bus *bus; 107 struct mctp *mctp; 108 size_t pkt_size; 109 size_t pkt_header; 110 size_t pkt_trailer; 111 int (*start)(struct mctp_binding *binding); 112 int (*tx)(struct mctp_binding *binding, struct mctp_pktbuf *pkt); 113 mctp_rx_fn control_rx; 114 void *control_rx_data; 115 }; 116 117 void mctp_binding_set_tx_enabled(struct mctp_binding *binding, bool enable); 118 119 /* 120 * Receive a packet from binding to core. Takes ownership of pkt, free()-ing it 121 * after use. 122 */ 123 void mctp_bus_rx(struct mctp_binding *binding, struct mctp_pktbuf *pkt); 124 125 /* environment-specific allocation */ 126 void mctp_set_alloc_ops(void *(*alloc)(size_t), 127 void (*free)(void *), 128 void *(realloc)(void *, size_t)); 129 130 /* environment-specific logging */ 131 132 void mctp_set_log_stdio(int level); 133 void mctp_set_log_syslog(void); 134 void mctp_set_log_custom(void (*fn)(int, const char *, va_list)); 135 136 /* these should match the syslog-standard LOG_* definitions, for 137 * easier use with syslog */ 138 #define MCTP_LOG_ERR 3 139 #define MCTP_LOG_WARNING 4 140 #define MCTP_LOG_NOTICE 5 141 #define MCTP_LOG_INFO 6 142 #define MCTP_LOG_DEBUG 7 143 144 145 #ifdef __cplusplus 146 } 147 #endif 148 149 #endif /* _LIBMCTP_H */ 150