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