mirror of
https://github.com/espressif/esp-idf.git
synced 2024-10-05 20:47:46 -04:00
420aef1ffe
* Target components pull in xtensa component directly * Use CPU HAL where applicable * Remove unnecessary xtensa headers * Compilation changes necessary to support non-xtensa gcc types (ie int32_t/uint32_t is no longer signed/unsigned int). Changes come from internal branch commit a6723fc
58 lines
1.9 KiB
C
58 lines
1.9 KiB
C
// Copyright 2010-2020 Espressif Systems (Shanghai) PTE LTD
|
|
//
|
|
// Licensed 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 "sdkconfig.h"
|
|
#include "bootloader_random.h"
|
|
#include "hal/cpu_hal.h"
|
|
#include "soc/wdev_reg.h"
|
|
|
|
#ifndef BOOTLOADER_BUILD
|
|
#include "esp_system.h"
|
|
#include "driver/periph_ctrl.h"
|
|
|
|
__attribute__((weak)) void bootloader_fill_random(void *buffer, size_t length)
|
|
{
|
|
return esp_fill_random(buffer, length);
|
|
}
|
|
|
|
#else
|
|
__attribute__((weak)) void bootloader_fill_random(void *buffer, size_t length)
|
|
{
|
|
uint8_t *buffer_bytes = (uint8_t *)buffer;
|
|
uint32_t random;
|
|
uint32_t start, now;
|
|
|
|
assert(buffer != NULL);
|
|
|
|
for (int i = 0; i < length; i++) {
|
|
if (i == 0 || i % 4 == 0) { /* redundant check is for a compiler warning */
|
|
/* in bootloader with ADC feeding HWRNG, we accumulate 1
|
|
bit of entropy per 40 APB cycles (==80 CPU cycles.)
|
|
|
|
To avoid reading the entire RNG hardware state out
|
|
as-is, we repeatedly read the RNG register and XOR all
|
|
values.
|
|
*/
|
|
random = REG_READ(WDEV_RND_REG);
|
|
start = cpu_hal_get_cycle_count();
|
|
do {
|
|
random ^= REG_READ(WDEV_RND_REG);
|
|
now = cpu_hal_get_cycle_count();
|
|
} while (now - start < 80 * 32 * 2); /* extra factor of 2 is precautionary */
|
|
}
|
|
buffer_bytes[i] = random >> ((i % 4) * 8);
|
|
}
|
|
}
|
|
|
|
#endif // BOOTLOADER_BUILD
|