65 lines
1.5 KiB
C
65 lines
1.5 KiB
C
/*
|
|
* Copyright (c) 2017 Intel Corporation
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
#include <string.h>
|
|
#include <random.h>
|
|
|
|
static inline u32_t random_esp32_get_u32(void)
|
|
{
|
|
/* The documentation specifies the random number generator at the
|
|
* following address, which is at odds with the SDK, that specifies
|
|
* it at 0x60035144. The fact that they're 0x200c0000 bytes apart
|
|
* (lower 16 bits are the same) suggests this might be the same
|
|
* register, just mirrored somewhere else in the address space.
|
|
* Confirmation is required.
|
|
*/
|
|
volatile u32_t *rng_data_reg = (u32_t *)0x3ff75144;
|
|
|
|
/* Read just once. This is not optimal as the generator has
|
|
* limited throughput due to scarce sources of entropy, specially
|
|
* with the radios turned off. Might want to revisit this.
|
|
*/
|
|
return *rng_data_reg;
|
|
}
|
|
|
|
static int random_esp32_get_entropy(struct device *device, u8_t *buf, u16_t len)
|
|
{
|
|
while (len) {
|
|
u32_t v = random_esp32_get_u32();
|
|
|
|
if (len >= sizeof(v)) {
|
|
memcpy(buf, &v, sizeof(v));
|
|
|
|
buf += sizeof(v);
|
|
len -= sizeof(v);
|
|
} else {
|
|
memcpy(buf, &v, len);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int random_esp32_init(struct device *device)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static struct random_driver_api random_esp32_api_funcs = {
|
|
.get_entropy = random_esp32_get_entropy
|
|
};
|
|
|
|
DEVICE_AND_API_INIT(random_esp32, CONFIG_RANDOM_NAME,
|
|
random_esp32_init, NULL, NULL,
|
|
PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
|
|
&random_esp32_api_funcs);
|
|
|
|
u32_t sys_rand32_get(void)
|
|
{
|
|
return random_esp32_get_u32();
|
|
}
|