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nimble-1.6.0-idf
esp-nimble/nimble/controller/src/ble_ll_utils.c
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/*
* 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_tmr.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
};
int
ble_ll_utils_verify_aa(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;
aa_low = aa & 0xffff;
aa_high = aa >> 16;
/* All four bytes cannot be equal */
if (aa_low == aa_high) {
return 0;
}
/* Upper 6 bits must have 2 transitions */
tmp = (int16_t)aa_high >> 10;
if (__builtin_popcount(tmp ^ (tmp >> 1)) < 2) {
return 0;
}
/* 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) {
return 0;
}
/* 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) {
return 0;
}
/* Cannot be more than 24 transitions */
if (transitions > 24) {
return 0;
}
return 1;
}
uint32_t
ble_ll_utils_calc_aa(void)
{
uint32_t aa;
do {
aa = ble_ll_rand();
} while (!ble_ll_utils_verify_aa(aa));
return aa;
}
uint32_t
ble_ll_utils_calc_seed_aa(void)
{
uint32_t seed_aa;
while (1) {
seed_aa = ble_ll_rand();
/* saa(19) == saa(15) */
if (!!(seed_aa & (1 << 19)) != !!(seed_aa & (1 << 15))) {
continue;
}
/* saa(22) = saa(16) */
if (!!(seed_aa & (1 << 22)) != !!(seed_aa & (1 << 16))) {
continue;
}
/* saa(22) != saa(15) */
if (!!(seed_aa & (1 << 22)) == !!(seed_aa & (1 << 15))) {
continue;
}
/* saa(25) == 0 */
if (seed_aa & (1 << 25)) {
continue;
}
/* saa(23) == 1 */
if (!(seed_aa & (1 << 23))) {
continue;
}
break;
}
return seed_aa;
}
uint32_t
ble_ll_utils_calc_big_aa(uint32_t seed_aa, uint32_t n)
{
uint32_t d;
uint32_t dw;
/* Core 5.3, Vol 6, Part B, 2.1.2 */
/* TODO simplify? */
d = ((35 * n) + 42) % 128;
dw = (!!(d & (1 << 0)) << 31) |
(!!(d & (1 << 0)) << 30) |
(!!(d & (1 << 0)) << 29) |
(!!(d & (1 << 0)) << 28) |
(!!(d & (1 << 0)) << 27) |
(!!(d & (1 << 0)) << 26) |
(!!(d & (1 << 1)) << 25) |
(!!(d & (1 << 6)) << 24) |
(!!(d & (1 << 1)) << 23) |
(!!(d & (1 << 5)) << 21) |
(!!(d & (1 << 4)) << 20) |
(!!(d & (1 << 3)) << 18) |
(!!(d & (1 << 2)) << 17);
return seed_aa ^ dw;
}
uint8_t
ble_ll_utils_chan_map_remap(const uint8_t *chan_map, uint8_t remap_index)
{
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 = chan_map[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_chan_map_used_get(const uint8_t *chan_map)
{
return __builtin_popcountll(((uint64_t)(chan_map[4] & 0x1f) << 32) |
get_le32(chan_map));
}
#if MYNEWT_VAL(BLE_LL_CFG_FEAT_LE_CSA2)
#if __thumb2__
static inline uint32_t
ble_ll_utils_csa2_perm(uint32_t val)
{
__asm__ volatile (".syntax unified \n"
"rbit %[val], %[val] \n"
"rev %[val], %[val] \n"
: [val] "+r" (val));
return val;
}
#else
static uint32_t
ble_ll_utils_csa2_perm(uint32_t in)
{
uint32_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;
}
#endif
static inline uint32_t
ble_ll_utils_csa2_mam(uint32_t a, uint32_t b)
{
return (17 * a + b) % 65536;
}
static uint16_t
ble_ll_utils_csa2_prn_s(uint16_t counter, uint16_t ch_id)
{
uint32_t prn_s;
prn_s = counter ^ ch_id;
prn_s = ble_ll_utils_csa2_perm(prn_s);
prn_s = ble_ll_utils_csa2_mam(prn_s, ch_id);
prn_s = ble_ll_utils_csa2_perm(prn_s);
prn_s = ble_ll_utils_csa2_mam(prn_s, ch_id);
prn_s = ble_ll_utils_csa2_perm(prn_s);
prn_s = ble_ll_utils_csa2_mam(prn_s, ch_id);
return prn_s;
}
static uint16_t
ble_ll_utils_csa2_prng(uint16_t counter, uint16_t ch_id)
{
uint16_t prn_s;
uint16_t prn_e;
prn_s = ble_ll_utils_csa2_prn_s(counter, ch_id);
prn_e = prn_s ^ ch_id;
return prn_e;
}
/* Find remap_idx for given chan_idx */
static uint16_t
ble_ll_utils_csa2_chan2remap(uint16_t chan_idx, const uint8_t *chan_map)
{
uint16_t remap_idx = 0;
uint32_t u32 = 0;
unsigned idx;
for (idx = 0; idx < 37; idx++) {
if ((idx % 8) == 0) {
u32 = chan_map[idx / 8];
}
if (u32 & 1) {
if (idx == chan_idx) {
return remap_idx;
}
remap_idx++;
}
u32 >>= 1;
}
BLE_LL_ASSERT(0);
return 0;
}
/* Find chan_idx at given remap_idx */
static uint16_t
ble_ll_utils_csa2_remap2chan(uint16_t remap_idx, const uint8_t *chan_map)
{
uint32_t u32 = 0;
unsigned idx;
for (idx = 0; idx < 37; idx++) {
if ((idx % 8) == 0) {
u32 = chan_map[idx / 8];
}
if (u32 & 1) {
if (!remap_idx) {
return idx;
}
remap_idx--;
}
u32 >>= 1;
}
BLE_LL_ASSERT(0);
return 0;
}
static uint16_t
ble_ll_utils_csa2_calc_chan_idx(uint16_t prn_e, uint8_t num_used_chans,
const uint8_t *chanm_map, uint16_t *remap_idx)
{
uint16_t chan_idx;
chan_idx = prn_e % 37;
if (chanm_map[chan_idx / 8] & (1 << (chan_idx % 8))) {
*remap_idx = ble_ll_utils_csa2_chan2remap(chan_idx, chanm_map);
return chan_idx;
}
*remap_idx = (num_used_chans * prn_e) / 65536;
chan_idx = ble_ll_utils_csa2_remap2chan(*remap_idx, chanm_map);
return chan_idx;
}
uint8_t
ble_ll_utils_dci_csa2(uint16_t counter, uint16_t chan_id,
uint8_t num_used_chans, const uint8_t *chan_map)
{
uint16_t prn_e;
uint16_t chan_idx;
uint16_t remap_idx;
prn_e = ble_ll_utils_csa2_prng(counter, chan_id);
chan_idx = ble_ll_utils_csa2_calc_chan_idx(prn_e, num_used_chans, chan_map,
&remap_idx);
return chan_idx;
}
uint16_t
ble_ll_utils_dci_iso_event(uint16_t counter, uint16_t chan_id,
uint16_t *prn_sub_lu, uint8_t chan_map_used,
const uint8_t *chan_map, uint16_t *remap_idx)
{
uint16_t prn_s;
uint16_t prn_e;
uint16_t chan_idx;
prn_s = ble_ll_utils_csa2_prn_s(counter, chan_id);
prn_e = prn_s ^ chan_id;
*prn_sub_lu = prn_s;
chan_idx = ble_ll_utils_csa2_calc_chan_idx(prn_e, chan_map_used, chan_map,
remap_idx);
return chan_idx;
}
uint16_t
ble_ll_utils_dci_iso_subevent(uint16_t chan_id, uint16_t *prn_sub_lu,
uint8_t chan_map_used, const uint8_t *chan_map,
uint16_t *remap_idx)
{
uint16_t prn_sub_se;
uint16_t chan_idx;
uint16_t d;
*prn_sub_lu = ble_ll_utils_csa2_perm(*prn_sub_lu);
*prn_sub_lu = ble_ll_utils_csa2_mam(*prn_sub_lu, chan_id);
prn_sub_se = *prn_sub_lu ^ chan_id;
/* Core 5.3, Vol 6, Part B, 4.5.8.3.6 (enjoy!) */
/* TODO optimize this somehow */
d = MAX(1, MAX(MIN(3, chan_map_used - 5),
MIN(11, (chan_map_used - 10) / 2)));
*remap_idx = (*remap_idx + d + prn_sub_se *
(chan_map_used - 2 * d + 1) / 65536) % chan_map_used;
chan_idx = ble_ll_utils_csa2_remap2chan(*remap_idx, chan_map);
return chan_idx;
}
#endif
uint32_t
ble_ll_utils_calc_window_widening(uint32_t anchor_point,
uint32_t last_anchor_point,
uint8_t central_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 = ble_ll_tmr_t2u(time_since_last_anchor) / 1000;
total_sca_ppm = g_ble_sca_ppm_tbl[central_sca] + MYNEWT_VAL(BLE_LL_SCA);
window_widening = (total_sca_ppm * delta_msec) / 1000;
}
return window_widening;
}
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