1 /* 2 * Copyright (c) 2020, The Linux Foundation. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 #include <stddef.h> 7 8 #include <drivers/qti/crypto/rng.h> 9 #include <lib/mmio.h> 10 qti_rng_get_data(uint8_t * out,uint32_t out_len)11int qti_rng_get_data(uint8_t *out, uint32_t out_len) 12 { 13 uint32_t tmp_rndm = 0; 14 uint32_t bytes_left = out_len; 15 int i = 0; 16 17 if (NULL == out || 0 == out_len) { 18 return -1; 19 } 20 21 /* 22 * RNG HW initialized at previous boot image. 23 * RNG clocks are expected to be ON. 24 */ 25 26 do { 27 /* There is no data to read */ 28 if ((mmio_read_32(SEC_PRNG_STATUS) & 29 SEC_PRNG_STATUS_DATA_AVAIL_BMSK) == 0) { 30 continue; 31 } 32 33 while ((tmp_rndm = mmio_read_32(SEC_PRNG_DATA_OUT)) == 0) { 34 ; 35 } 36 37 for (i = 0; i < 4; i++) { 38 *out = (uint8_t) (tmp_rndm >> (8 * i)); 39 40 out++; 41 bytes_left--; 42 43 if (bytes_left == 0) { 44 break; 45 } 46 } 47 48 } while (bytes_left != 0); 49 50 return 0; 51 } 52