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/*
* Copyright (c) 2017 - 2020, Broadcom
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <common/debug.h>
#include <drivers/delay_timer.h>
#include <lib/mmio.h>
#include <platform_def.h>
#define RNG_CTRL_REG (RNG_BASE_ADDR + 0x00)
#define RNG_CTRL_MASK 0x00001FFF
#define RNG_CTRL_ENABLE 0x00000001
#define RNG_CTRL_DISABLE 0x00000000
#define RNG_SOFT_RESET_REG (RNG_BASE_ADDR + 0x04)
#define RNG_SOFT_RESET_MASK 0x00000001
#define RNG_FIFO_DATA_REG (RNG_BASE_ADDR + 0x20)
#define RNG_FIFO_COUNT_REG (RNG_BASE_ADDR + 0x24)
#define RNG_FIFO_COUNT_MASK 0x000000FF
#define RNG_FIFO_WORDS_MAX 16
#define MAX_WAIT_COUNT_50US 20000
static void rng_reset(void)
{
/* Disable RBG */
mmio_clrbits_32(RNG_CTRL_REG, RNG_CTRL_MASK);
/* Reset RNG and RBG */
mmio_setbits_32(RNG_SOFT_RESET_REG, RNG_SOFT_RESET_MASK);
/* Take all out of reset */
mmio_clrbits_32(RNG_SOFT_RESET_REG, RNG_SOFT_RESET_MASK);
}
static void rng_enable(void)
{
/* Setup RNG. */
mmio_clrsetbits_32(RNG_CTRL_REG, RNG_CTRL_MASK, RNG_CTRL_ENABLE);
}
int rng_init(void)
{
rng_reset();
rng_enable();
return 0;
}
int rng_read(uint32_t *p_out, uint32_t *words_read)
{
uint32_t available_words;
uint32_t i;
uint32_t word_processed = 0;
uint32_t wait_count = MAX_WAIT_COUNT_50US;
if (*words_read == 0) {
ERROR("RNG Parameter: No word requested\n");
return -1;
}
do {
available_words = mmio_read_32(RNG_FIFO_COUNT_REG);
available_words &= RNG_FIFO_COUNT_MASK;
if (available_words != 0) {
available_words = MIN(available_words,
*words_read - word_processed);
for (i = 0; i < available_words; i++)
p_out[word_processed + i] =
mmio_read_32(RNG_FIFO_DATA_REG);
word_processed += available_words;
} else {
udelay(50);
}
if (word_processed == *words_read)
break;
} while (--wait_count);
if (word_processed != *words_read) {
ERROR("RNG Timeout: requested %d word(s) got %d\n",
*words_read, word_processed);
*words_read = word_processed;
return -1;
}
return 0;
}
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