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52 lines
1.7 KiB
52 lines
1.7 KiB
/* |
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* Copyright (c) 2022, Commonwealth Scientific and Industrial Research |
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* Organisation (CSIRO) ABN 41 687 119 230. |
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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 zephyr_bt_hci_entropy |
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#include <zephyr/drivers/entropy.h> |
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#include <zephyr/bluetooth/hci.h> |
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#include <string.h> |
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static int entropy_bt_init(const struct device *dev) |
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{ |
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/* Nothing to do */ |
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return 0; |
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} |
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static int entropy_bt_get_entropy(const struct device *dev, |
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uint8_t *buffer, uint16_t length) |
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{ |
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/* Do not wait for BT to be ready (i.e. bt_is_ready()) before issueing |
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* the command. The reason is that when crypto is enabled and the PSA |
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* Crypto API support is provided through Mbed TLS, random number generator |
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* needs to be available since the very first call to psa_crypto_init() |
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* which is usually done before BT is completely initialized. |
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* On the other hand, in devices like the nrf5340, the crytographically |
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* secure RNG is owned by the cpu_net, so the cpu_app needs to poll it |
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* to get random data. Again, there is no need to wait for BT to be |
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* completely initialized for this kind of support. Just try to send the |
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* request through HCI. If the command fails for any reason, then |
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* we return failure anyway. |
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*/ |
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return bt_hci_le_rand(buffer, length); |
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} |
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/* HCI commands cannot be run from an interrupt context */ |
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static DEVICE_API(entropy, entropy_bt_api) = { |
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.get_entropy = entropy_bt_get_entropy, |
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.get_entropy_isr = NULL |
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}; |
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#define ENTROPY_BT_HCI_INIT(inst) \ |
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DEVICE_DT_INST_DEFINE(inst, entropy_bt_init, \ |
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NULL, NULL, NULL, \ |
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PRE_KERNEL_1, \ |
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CONFIG_KERNEL_INIT_PRIORITY_DEVICE, \ |
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&entropy_bt_api); |
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DT_INST_FOREACH_STATUS_OKAY(ENTROPY_BT_HCI_INIT)
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