Thank you to anyone who has already donated - your generous donations helped make three months of treatment possible.
My brother Nate continues to fight stage IV Hodgkin's lymphoma. He's just 31, with a wife and baby girl. They have no active income (since he's been unable to return to work), no insurance, and cannot afford the treatment he needs. Nate and his family need your help. Please consider a donation, every dollar helps. Thanks.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 |
Index: apps/iap.c =================================================================== --- apps/iap.c (revision 29882) +++ apps/iap.c (working copy) @@ -21,6 +21,7 @@ #include <stdarg.h> #include <string.h> +#include "panic.h" #include "iap.h" #include "button.h" #include "config.h" @@ -63,6 +64,27 @@ static char cur_dbrecord[5] = {0}; +/* states of the iap de-framing state machine */ +enum fsm_state { + ST_SYNC, /* wait for 0xFF sync byte */ + ST_SOF, /* wait for 0x55 start-of-frame byte */ + ST_LEN, /* receive length byte (small packet) */ + ST_LENH, /* receive length high byte (large packet) */ + ST_LENL, /* receive length low byte (large packet) */ + ST_DATA, /* receive data */ + ST_CHECK /* verify checksum */ +}; + +static struct state_t { + enum fsm_state state; /* current fsm state */ + int len; /* payload data length */ + unsigned char *payload; /* payload data pointer */ + int check; /* running checksum */ + int count; /* playload bytes counter */ +} fsm_state = { + .state = ST_SYNC +}; + static void put_u32(unsigned char *buf, uint32_t data) { buf[0] = (data >> 24) & 0xFF; @@ -168,36 +190,80 @@ bool iap_getc(unsigned char x) { - static unsigned char last_x = 0; static bool newpkt = true; - static unsigned char chksum = 0; - - /* Restart if the sync word is seen */ - if(x == 0x55 && last_x == 0xff/* && newpkt*/) - { - serbuf[0] = 0; + struct state_t *s = &fsm_state; + + /* run FSM to detect and extract a valid frame */ + switch (s->state) { + case ST_SYNC: serbuf_i = 0; - chksum = 0; - newpkt = false; - } - else - { - if(serbuf_i >= RX_BUFLEN) - serbuf_i = 0; - - serbuf[serbuf_i++] = x; - chksum += x; - } - last_x = x; - - /* Broadcast to queue if we have a complete message */ - if(serbuf_i && (serbuf_i == serbuf[0]+2)) - { - serbuf_i = 0; - newpkt = true; - if(chksum == 0) + if (x == 0xFF) { + s->state = ST_SOF; + } + break; + case ST_SOF: + if (x == 0x55) { + /* received a valid sync-SOF pair */ + newpkt = false; + s->state = ST_LEN; + } else { + s->state = ST_SYNC; + return iap_getc(x); + } + break; + case ST_LEN: + s->check = x; + s->count = 0; + if (x == 0) { + /* large packet */ + s->state = ST_LENH; + } else { + /* small packet */ + s->len = x; + s->payload = &serbuf[3]; + s->state = ST_DATA; + } + break; + case ST_LENH: + s->check += x; + s->len = x << 8; + s->state = ST_LENL; + break; + case ST_LENL: + s->check += x; + s->len += x; + s->payload = &serbuf[5]; + if ((s->len == 0) || (s->len > (RX_BUFLEN - 6))) { + /* invalid length */ + s->state = ST_SYNC; + return iap_getc(x); + } else { + s->state = ST_DATA; + } + break; + case ST_DATA: + s->check += x; + if (++s->count == s->len) { + s->state = ST_CHECK; + } + break; + case ST_CHECK: + s->check += x; + if ((s->check & 0xFF) == 0) { + /* done, received a valid frame */ + newpkt = true; queue_post(&button_queue, SYS_IAP_HANDLEPKT, 0); + } + s->state = ST_SYNC; + break; + default: + panicf("Unhandled iap state %d", (int) s->state); + break; } + + /* store all incoming data in serbuf */ + serbuf[serbuf_i++] = x; + return newpkt; } @@ -1004,8 +1070,10 @@ void iap_handlepkt(void) { + struct state_t *s = &fsm_state; + if(!iap_setupflag) return; - if(serbuf[0] == 0) return; + if (s->len == 0) return; /* if we are waiting for a remote button to go out, delay the handling of the new packet */ @@ -1015,20 +1083,17 @@ return; } - /* get length and payload from serbuf */ - unsigned int len = serbuf[0]; - unsigned char *payload = &serbuf[1]; - - unsigned char mode = payload[0]; + /* handle command by mode */ + unsigned char mode = s->payload[0]; switch (mode) { - case 0: iap_handlepkt_mode0(len, payload); break; - case 2: iap_handlepkt_mode2(len, payload); break; - case 3: iap_handlepkt_mode3(len, payload); break; - case 4: iap_handlepkt_mode4(len, payload); break; - case 7: iap_handlepkt_mode7(len, payload); break; + case 0: iap_handlepkt_mode0(s->len, s->payload); break; + case 2: iap_handlepkt_mode2(s->len, s->payload); break; + case 3: iap_handlepkt_mode3(s->len, s->payload); break; + case 4: iap_handlepkt_mode4(s->len, s->payload); break; + case 7: iap_handlepkt_mode7(s->len, s->payload); break; } - serbuf[0] = 0; + s->len = 0; } int remote_control_rx(void) Index: firmware/export/iap.h =================================================================== --- firmware/export/iap.h (revision 29882) +++ firmware/export/iap.h (working copy) @@ -22,7 +22,7 @@ #include <stdbool.h> -#define RX_BUFLEN 260 +#define RX_BUFLEN 512 #define TX_BUFLEN 128 extern bool iap_getc(unsigned char x); |
