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