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152 lines
4.9 KiB
152 lines
4.9 KiB
/* |
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* Copyright (c) 2025 TOKITA Hiroshi |
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* |
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* SPDX-License-Identifier: Apache-2.0 |
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*/ |
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#define DT_DRV_COMPAT brcm_iproc_rng200 |
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#include <zephyr/logging/log.h> |
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LOG_MODULE_REGISTER(iproc_rng200_entropy, CONFIG_ENTROPY_LOG_LEVEL); |
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#include <zephyr/device.h> |
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#include <zephyr/drivers/entropy.h> |
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#include <errno.h> |
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#include <zephyr/init.h> |
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#include <zephyr/kernel.h> |
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#define IPROC_RNG200_CTRL_OFFS 0x00 |
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#define IPROC_RNG200_RNG_RESET_OFFS 0x04 |
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#define IPROC_RNG200_RBG_RESET_OFFS 0x08 |
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#define IPROC_RNG200_RESERVED1_OFFS 0x0c |
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#define IPROC_RNG200_RESERVED2_OFFS 0x10 |
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#define IPROC_RNG200_RESERVED3_OFFS 0x14 |
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#define IPROC_RNG200_INT_STATUS_OFFS 0x18 |
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#define IPROC_RNG200_RESERVED4_OFFS 0x1c |
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#define IPROC_RNG200_FIFO_DATA_OFFS 0x20 |
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#define IPROC_RNG200_FIFO_COUNT_OFFS 0x24 |
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#define IPROC_RNG200_CTRL_RBG_EN BIT(0) |
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#define IPROC_RNG200_RESET_EN BIT(0) |
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#define IPROC_RNG200_INT_STATUS_NIST_FAIL BIT(5) |
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#define IPROC_RNG200_INT_STATUS_MASTER_FAIL_LOCKOUT BIT(31) |
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#define IPROC_RNG200_CTRL_RBG_EN_MASK BIT_MASK(13) |
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#define IPROC_RNG200_FIFO_COUNT_MASK BIT_MASK(8) |
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/* time needed to fill fifo when empty */ |
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#define IPROC_RNG200_FIFO_REFILL_TIME_USEC 40 |
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#define IPROC_RNG200_FIFO_REFILL_MAX_RETRIES 5 |
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#define DEV_CFG(dev) ((const struct iproc_rng200_config *)(dev)->config) |
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#define DEV_DATA(dev) ((struct iproc_rng200_data *)(dev)->data) |
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struct iproc_rng200_config { |
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DEVICE_MMIO_NAMED_ROM(base_addr); |
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}; |
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struct iproc_rng200_data { |
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DEVICE_MMIO_NAMED_RAM(base_addr); |
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struct k_mutex mutex; |
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}; |
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static int iproc_rng200_driver_init(const struct device *dev) |
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{ |
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struct iproc_rng200_data *const data = dev->data; |
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k_mutex_init(&data->mutex); |
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DEVICE_MMIO_NAMED_MAP(dev, base_addr, K_MEM_CACHE_NONE); |
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const mem_addr_t base = DEVICE_MMIO_NAMED_GET(dev, base_addr); |
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const uint32_t val = |
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sys_read32(base + IPROC_RNG200_CTRL_OFFS) & IPROC_RNG200_CTRL_RBG_EN_MASK; |
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sys_write32(val & ~IPROC_RNG200_CTRL_RBG_EN, base + IPROC_RNG200_CTRL_OFFS); |
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return 0; |
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} |
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static int iproc_rng200_driver_get_entropy(const struct device *dev, uint8_t *buffer, |
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uint16_t length) |
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{ |
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const mem_addr_t base = DEVICE_MMIO_NAMED_GET(dev, base_addr); |
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const uint32_t word_count = DIV_ROUND_UP(length, 4); |
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struct iproc_rng200_data *const data = dev->data; |
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uint32_t retries_left; |
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uint32_t random_word; |
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for (uint32_t i = 0; i < word_count; i++) { |
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retries_left = IPROC_RNG200_FIFO_REFILL_MAX_RETRIES; |
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k_mutex_lock(&data->mutex, K_FOREVER); |
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while (true) { |
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const uint32_t status = sys_read32(base + IPROC_RNG200_INT_STATUS_OFFS); |
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uint32_t val; |
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if (status & (IPROC_RNG200_INT_STATUS_MASTER_FAIL_LOCKOUT | |
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IPROC_RNG200_INT_STATUS_NIST_FAIL)) { |
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sys_write32(0xFFFFFFFF, base + IPROC_RNG200_INT_STATUS_OFFS); |
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val = sys_read32(base + IPROC_RNG200_RNG_RESET_OFFS); |
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sys_write32(val | IPROC_RNG200_RESET_EN, |
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base + IPROC_RNG200_RNG_RESET_OFFS); |
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val = sys_read32(base + IPROC_RNG200_RBG_RESET_OFFS); |
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sys_write32(val | IPROC_RNG200_RESET_EN, |
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base + IPROC_RNG200_RBG_RESET_OFFS); |
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val = sys_read32(base + IPROC_RNG200_RNG_RESET_OFFS); |
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sys_write32(val & ~IPROC_RNG200_RESET_EN, |
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base + IPROC_RNG200_RNG_RESET_OFFS); |
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val = sys_read32(base + IPROC_RNG200_RBG_RESET_OFFS); |
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sys_write32(val & ~IPROC_RNG200_RESET_EN, |
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base + IPROC_RNG200_RBG_RESET_OFFS); |
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} |
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/* make sure fifo has at least one random word */ |
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const uint32_t fcnt = sys_read32(base + IPROC_RNG200_FIFO_COUNT_OFFS); |
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if ((fcnt & IPROC_RNG200_FIFO_COUNT_MASK) > 0) { |
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/* get new random word */ |
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random_word = sys_read32(base + IPROC_RNG200_FIFO_DATA_OFFS); |
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break; |
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} |
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/* currently no random values available, thus wait */ |
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retries_left--; |
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if (!retries_left) { |
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/* number of retries exhausted, give up */ |
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k_mutex_unlock(&data->mutex); |
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return -ETIMEDOUT; |
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} |
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k_sleep(K_USEC(IPROC_RNG200_FIFO_REFILL_TIME_USEC)); |
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} |
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k_mutex_unlock(&data->mutex); |
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memcpy(&buffer[i * 4], &random_word, MIN(length, 4)); |
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length -= 4; |
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} |
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return 0; |
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} |
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static DEVICE_API(entropy, iproc_rng200_entropy_api) = { |
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.get_entropy = iproc_rng200_driver_get_entropy, |
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}; |
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#define IPROC_RNG200_INIT(n) \ |
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static const struct iproc_rng200_config iproc_rng200_##n##_cfg = { \ |
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DEVICE_MMIO_NAMED_ROM_INIT(base_addr, DT_DRV_INST(n)), \ |
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}; \ |
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static struct iproc_rng200_data iproc_rng200_##n##_data; \ |
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\ |
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DEVICE_DT_INST_DEFINE(n, iproc_rng200_driver_init, NULL, &iproc_rng200_##n##_data, \ |
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&iproc_rng200_##n##_cfg, PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY, \ |
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&iproc_rng200_entropy_api); |
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DT_INST_FOREACH_STATUS_OKAY(IPROC_RNG200_INIT)
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