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64 lines
1.8 KiB
64 lines
1.8 KiB
/* Copyright (c) 2013-2014, 2016-2018, The Linux Foundation. All rights
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* reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/hw_random.h>
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#include <linux/io.h>
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#include <soc/qcom/scm.h>
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#include <asm/cacheflush.h>
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#define TZ_SVC_CRYPTO 10
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#define PRNG_CMD_ID 0x01
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struct tz_prng_data {
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uint8_t *out_buf;
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uint32_t out_buf_sz;
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} __packed;
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#define RANDOM_BUFFER_SIZE PAGE_SIZE
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char random_buffer[RANDOM_BUFFER_SIZE] __aligned(PAGE_SIZE);
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void __init init_random_pool(void)
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{
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struct tz_prng_data data;
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int ret;
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struct scm_desc desc;
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data.out_buf = (uint8_t *) virt_to_phys(random_buffer);
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desc.args[0] = (unsigned long) data.out_buf;
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desc.args[1] = data.out_buf_sz = SZ_512;
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desc.arginfo = SCM_ARGS(2, SCM_RW, SCM_VAL);
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dmac_flush_range(random_buffer, random_buffer + RANDOM_BUFFER_SIZE);
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ret = scm_call2(SCM_SIP_FNID(TZ_SVC_CRYPTO, PRNG_CMD_ID), &desc);
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if (!ret) {
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u64 bytes_received = desc.ret[0];
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if (bytes_received != SZ_512)
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pr_warn("Did not receive the expected number of bytes from PRNG: %llu\n",
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bytes_received);
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dmac_inv_range(random_buffer, random_buffer +
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RANDOM_BUFFER_SIZE);
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bytes_received = (bytes_received <= RANDOM_BUFFER_SIZE) ?
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bytes_received : RANDOM_BUFFER_SIZE;
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add_hwgenerator_randomness(random_buffer, bytes_received,
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bytes_received << 3);
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}
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}
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