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Bluetooth: controller: Optimize RNG access

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This commit optimizes access to RNG driver by taking advantage
of the data structures layout. As result, number of calls to RNG
driver is reduced.

Signed-off-by: Piotr Zięcik <piotr.ziecik@nordicsemi.no>
This commit is contained in:
Piotr Zięcik 2018-10-03 12:11:13 +02:00 • committed by Carles Cufí
commit 708468bdce
1 changed files with 26 additions and 6 deletions
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32
subsys/bluetooth/controller/ll_sw/ctrl.c
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@ -9398,10 +9398,20 @@ static void enc_req_reused_send(struct connection *conn,
conn->llcp.encryption.ediv[0];
pdu_ctrl_tx->llctrl.enc_req.ediv[1] =
conn->llcp.encryption.ediv[1];
/*
* Take advantage of the fact that ivm and skdm fields, which both have
* to be filled with random data, are adjacent and use single call to
* the entropy driver.
*/
BUILD_ASSERT(offsetof(__typeof(pdu_ctrl_tx->llctrl.enc_req), ivm) ==
(offsetof(__typeof(pdu_ctrl_tx->llctrl.enc_req), skdm) +
sizeof(pdu_ctrl_tx->llctrl.enc_req.skdm)));
/* NOTE: if not sufficient random numbers, ignore waiting */
entropy_get_entropy_isr(_radio.entropy, pdu_ctrl_tx->llctrl.enc_req.skdm,
sizeof(pdu_ctrl_tx->llctrl.enc_req.skdm), 0);
entropy_get_entropy_isr(_radio.entropy, pdu_ctrl_tx->llctrl.enc_req.ivm,
entropy_get_entropy_isr(_radio.entropy,
pdu_ctrl_tx->llctrl.enc_req.skdm,
sizeof(pdu_ctrl_tx->llctrl.enc_req.skdm) +
sizeof(pdu_ctrl_tx->llctrl.enc_req.ivm), 0);
}
@ -9421,10 +9431,20 @@ static u8_t enc_rsp_send(struct connection *conn)
pdu_ctrl_tx->len = offsetof(struct pdu_data_llctrl, enc_rsp) +
sizeof(struct pdu_data_llctrl_enc_rsp);
pdu_ctrl_tx->llctrl.opcode = PDU_DATA_LLCTRL_TYPE_ENC_RSP;
/*
* Take advantage of the fact that ivs and skds fields, which both have
* to be filled with random data, are adjacent and use single call to
* the entropy driver.
*/
BUILD_ASSERT(offsetof(__typeof(pdu_ctrl_tx->llctrl.enc_rsp), ivs) ==
(offsetof(__typeof(pdu_ctrl_tx->llctrl.enc_rsp), skds) +
sizeof(pdu_ctrl_tx->llctrl.enc_rsp.skds)));
/* NOTE: if not sufficient random numbers, ignore waiting */
entropy_get_entropy_isr(_radio.entropy, pdu_ctrl_tx->llctrl.enc_rsp.skds,
sizeof(pdu_ctrl_tx->llctrl.enc_rsp.skds), 0);
entropy_get_entropy_isr(_radio.entropy, pdu_ctrl_tx->llctrl.enc_rsp.ivs,
entropy_get_entropy_isr(_radio.entropy,
pdu_ctrl_tx->llctrl.enc_rsp.skds,
sizeof(pdu_ctrl_tx->llctrl.enc_rsp.skds) +
sizeof(pdu_ctrl_tx->llctrl.enc_rsp.ivs), 0);
/* things from slave stored for session key calculation */