e00eed79aa
As part of closer integration into Zephyr, remove the use of custom assert mechanism and use BT_ASSERT instead. Jira: ZEP-761 Change-id: I27f37d697b0a84bc001754a8d0b4dbb6ddb54298 Signed-off-by: Vinayak Chettimada <vinayak.kariappa.chettimada@nordicsemi.no>
126 lines
2.4 KiB
C
126 lines
2.4 KiB
C
/*
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* Copyright (c) 2016 Nordic Semiconductor ASA
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* Copyright (c) 2016 Vinayak Kariappa Chettimada
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "nrf.h"
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#include "rand.h"
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#include "debug.h"
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#define RAND_RESERVED (4)
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struct rand {
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uint8_t count;
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uint8_t first;
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uint8_t last;
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uint8_t rand[1];
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};
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static struct rand *_rand;
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void rand_init(uint8_t *context, uint8_t context_len)
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{
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BT_ASSERT(context_len > sizeof(struct rand));
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_rand = (struct rand *)context;
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_rand->count = context_len - sizeof(struct rand) + 1;
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_rand->first = _rand->last = 0;
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NRF_RNG->CONFIG = RNG_CONFIG_DERCEN_Msk;
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NRF_RNG->EVENTS_VALRDY = 0;
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NRF_RNG->INTENSET = RNG_INTENSET_VALRDY_Msk;
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NVIC_SetPriority(RNG_IRQn, 2);
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NVIC_EnableIRQ(RNG_IRQn);
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NRF_RNG->TASKS_START = 1;
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}
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uint32_t rand_get(uint8_t octets, uint8_t *rand)
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{
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uint8_t reserved;
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uint8_t first;
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while (octets) {
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if (_rand->first == _rand->last) {
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break;
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}
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rand[--octets] = _rand->rand[_rand->first];
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first = _rand->first + 1;
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if (first == _rand->count) {
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first = 0;
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}
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_rand->first = first;
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}
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reserved = RAND_RESERVED;
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first = _rand->first;
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while (reserved--) {
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if (first == _rand->last) {
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NRF_RNG->TASKS_START = 1;
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break;
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}
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first++;
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if (first == _rand->count) {
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first = 0;
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}
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}
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return octets;
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}
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void rng_isr(void)
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{
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if (NRF_RNG->EVENTS_VALRDY) {
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uint8_t last;
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last = _rand->last + 1;
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if (last == _rand->count) {
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last = 0;
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}
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if (last == _rand->first) {
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/* this condition should not happen
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* , but due to probable bug in HW
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* , new value could be generated
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* before task is stopped.
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*/
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NRF_RNG->TASKS_STOP = 1;
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NRF_RNG->EVENTS_VALRDY = 0;
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return;
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}
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_rand->rand[_rand->last] = NRF_RNG->VALUE;
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_rand->last = last;
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last = _rand->last + 1;
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if (last == _rand->count) {
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last = 0;
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}
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NRF_RNG->EVENTS_VALRDY = 0;
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if (last == _rand->first) {
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NRF_RNG->TASKS_STOP = 1;
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}
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}
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}
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