ref: 0195ece317d15bcba7dfbd74b58bb8dbcd3bca0a
src/libs/mynewt-nimble/nimble/controller/src/ble_ll_utils.c
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 |
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ #include <assert.h> #include <stdlib.h> #include "nimble/ble.h" #include "controller/ble_ll.h" #include "controller/ble_ll_utils.h" /* 37 bits require 5 bytes */ #define BLE_LL_CHMAP_LEN (5) /* Sleep clock accuracy table (in ppm) */ static const uint16_t g_ble_sca_ppm_tbl[8] = { 500, 250, 150, 100, 75, 50, 30, 20 }; uint32_t ble_ll_utils_calc_access_addr(void) { uint32_t aa; uint16_t aa_low; uint16_t aa_high; uint32_t temp; uint32_t mask; uint32_t prev_bit; uint8_t bits_diff; uint8_t consecutive; uint8_t transitions; uint8_t ones; int tmp; /* Calculate a random access address */ aa = 0; while (1) { /* Get two, 16-bit random numbers */ aa_low = rand() & 0xFFFF; aa_high = rand() & 0xFFFF; /* All four bytes cannot be equal */ if (aa_low == aa_high) { continue; } /* Upper 6 bits must have 2 transitions */ tmp = (int16_t)aa_high >> 10; if (__builtin_popcount(tmp ^ (tmp >> 1)) < 2) { continue; } /* Cannot be access address or be 1 bit different */ aa = aa_high; aa = (aa << 16) | aa_low; bits_diff = 0; temp = aa ^ BLE_ACCESS_ADDR_ADV; for (mask = 0x00000001; mask != 0; mask <<= 1) { if (mask & temp) { ++bits_diff; if (bits_diff > 1) { break; } } } if (bits_diff <= 1) { continue; } /* Cannot have more than 24 transitions */ transitions = 0; consecutive = 1; ones = 0; mask = 0x00000001; while (mask < 0x80000000) { prev_bit = aa & mask; mask <<= 1; if (mask & aa) { if (prev_bit == 0) { ++transitions; consecutive = 1; } else { ++consecutive; } } else { if (prev_bit == 0) { ++consecutive; } else { ++transitions; consecutive = 1; } } if (prev_bit) { ones++; } /* 8 lsb should have at least three 1 */ if (mask == 0x00000100 && ones < 3) { break; } /* 16 lsb should have no more than 11 transitions */ if (mask == 0x00010000 && transitions > 11) { break; } /* This is invalid! */ if (consecutive > 6) { /* Make sure we always detect invalid sequence below */ mask = 0; break; } } /* Invalid sequence found */ if (mask != 0x80000000) { continue; } /* Cannot be more than 24 transitions */ if (transitions > 24) { continue; } /* We have a valid access address */ break; } return aa; } uint8_t ble_ll_utils_remapped_channel(uint8_t remap_index, const uint8_t *chanmap) { uint8_t cntr; uint8_t mask; uint8_t usable_chans; uint8_t chan; int i, j; /* NOTE: possible to build a map but this would use memory. For now, * we just calculate * Iterate through channel map to find this channel */ chan = 0; cntr = 0; for (i = 0; i < BLE_LL_CHMAP_LEN; i++) { usable_chans = chanmap[i]; if (usable_chans != 0) { mask = 0x01; for (j = 0; j < 8; j++) { if (usable_chans & mask) { if (cntr == remap_index) { return (chan + j); } ++cntr; } mask <<= 1; } } chan += 8; } /* we should never reach here */ BLE_LL_ASSERT(0); return 0; } uint8_t ble_ll_utils_calc_num_used_chans(const uint8_t *chmap) { int i; int j; uint8_t mask; uint8_t chanbyte; uint8_t used_channels; used_channels = 0; for (i = 0; i < BLE_LL_CHMAP_LEN; ++i) { chanbyte = chmap[i]; if (chanbyte) { if (chanbyte == 0xff) { used_channels += 8; } else { mask = 0x01; for (j = 0; j < 8; ++j) { if (chanbyte & mask) { ++used_channels; } mask <<= 1; } } } } return used_channels; } #if MYNEWT_VAL(BLE_LL_CFG_FEAT_LE_CSA2) static uint16_t ble_ll_utils_csa2_perm(uint16_t in) { uint16_t out = 0; int i; for (i = 0; i < 8; i++) { out |= ((in >> i) & 0x00000001) << (7 - i); } for (i = 8; i < 16; i++) { out |= ((in >> i) & 0x00000001) << (15 + 8 - i); } return out; } static uint16_t ble_ll_utils_csa2_prng(uint16_t counter, uint16_t ch_id) { uint16_t prn_e; prn_e = counter ^ ch_id; prn_e = ble_ll_utils_csa2_perm(prn_e); prn_e = (prn_e * 17) + ch_id; prn_e = ble_ll_utils_csa2_perm(prn_e); prn_e = (prn_e * 17) + ch_id; prn_e = ble_ll_utils_csa2_perm(prn_e); prn_e = (prn_e * 17) + ch_id; prn_e = prn_e ^ ch_id; return prn_e; } uint8_t ble_ll_utils_calc_dci_csa2(uint16_t event_cntr, uint16_t channel_id, uint8_t num_used_chans, const uint8_t *chanmap) { uint16_t channel_unmapped; uint8_t remap_index; uint16_t prn_e; uint8_t bitpos; prn_e = ble_ll_utils_csa2_prng(event_cntr, channel_id); channel_unmapped = prn_e % 37; /* * If unmapped channel is the channel index of a used channel it is used * as channel index. */ bitpos = 1 << (channel_unmapped & 0x07); if (chanmap[channel_unmapped >> 3] & bitpos) { return channel_unmapped; } remap_index = (num_used_chans * prn_e) / 0x10000; return ble_ll_utils_remapped_channel(remap_index, chanmap); } #endif uint32_t ble_ll_utils_calc_window_widening(uint32_t anchor_point, uint32_t last_anchor_point, uint8_t master_sca) { uint32_t total_sca_ppm; uint32_t window_widening; int32_t time_since_last_anchor; uint32_t delta_msec; window_widening = 0; time_since_last_anchor = (int32_t)(anchor_point - last_anchor_point); if (time_since_last_anchor > 0) { delta_msec = os_cputime_ticks_to_usecs(time_since_last_anchor) / 1000; total_sca_ppm = g_ble_sca_ppm_tbl[master_sca] + MYNEWT_VAL(BLE_LL_OUR_SCA); window_widening = (total_sca_ppm * delta_msec) / 1000; } return window_widening; } |