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 63 /* MCTP core */ 64 struct mctp; 65 struct mctp_bus; 66 67 struct mctp *mctp_init(void); 68 void mctp_set_max_message_size(struct mctp *mctp, size_t message_size); 69 void mctp_destroy(struct mctp *mctp); 70 71 /* Register a binding to the MCTP core, and creates a bus (populating 72 * binding->bus). 73 * 74 * If this function is called, the MCTP stack is initialised as an 'endpoint', 75 * and will deliver local packets to a RX callback - see `mctp_set_rx_all()` 76 * below. 77 */ 78 int mctp_register_bus(struct mctp *mctp, 79 struct mctp_binding *binding, 80 mctp_eid_t eid); 81 82 /* Create a simple bidirectional bridge between busses. 83 * 84 * In this mode, the MCTP stack is initialised as a bridge. There is no EID 85 * defined, so no packets are considered local. Instead, all messages from one 86 * binding are forwarded to the other. 87 */ 88 int mctp_bridge_busses(struct mctp *mctp, 89 struct mctp_binding *b1, struct mctp_binding *b2); 90 91 typedef void (*mctp_rx_fn)(uint8_t src_eid, void *data, 92 void *msg, size_t len); 93 94 int mctp_set_rx_all(struct mctp *mctp, mctp_rx_fn fn, void *data); 95 96 int mctp_message_tx(struct mctp *mctp, mctp_eid_t eid, 97 void *msg, size_t msg_len); 98 99 /* hardware bindings */ 100 struct mctp_binding { 101 const char *name; 102 uint8_t version; 103 struct mctp_bus *bus; 104 struct mctp *mctp; 105 size_t pkt_size; 106 size_t pkt_pad; 107 int (*start)(struct mctp_binding *binding); 108 int (*tx)(struct mctp_binding *binding, struct mctp_pktbuf *pkt); 109 mctp_rx_fn control_rx; 110 void *control_rx_data; 111 }; 112 113 void mctp_binding_set_tx_enabled(struct mctp_binding *binding, bool enable); 114 115 /* 116 * Receive a packet from binding to core. Takes ownership of pkt, free()-ing it 117 * after use. 118 */ 119 void mctp_bus_rx(struct mctp_binding *binding, struct mctp_pktbuf *pkt); 120 121 /* environment-specific allocation */ 122 void mctp_set_alloc_ops(void *(*alloc)(size_t), 123 void (*free)(void *), 124 void *(realloc)(void *, size_t)); 125 126 /* environment-specific logging */ 127 128 void mctp_set_log_stdio(int level); 129 void mctp_set_log_syslog(void); 130 void mctp_set_log_custom(void (*fn)(int, const char *, va_list)); 131 132 /* these should match the syslog-standard LOG_* definitions, for 133 * easier use with syslog */ 134 #define MCTP_LOG_ERR 3 135 #define MCTP_LOG_WARNING 4 136 #define MCTP_LOG_NOTICE 5 137 #define MCTP_LOG_INFO 6 138 #define MCTP_LOG_DEBUG 7 139 140 141 #ifdef __cplusplus 142 } 143 #endif 144 145 #endif /* _LIBMCTP_H */ 146