1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * sun8i-ce-trng.c - hardware cryptographic offloader for 4 * Allwinner H3/A64/H5/H2+/H6/R40 SoC 5 * 6 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com> 7 * 8 * This file handle the TRNG 9 * 10 * You could find a link for the datasheet in Documentation/arm/sunxi.rst 11 */ 12 #include "sun8i-ce.h" 13 #include <linux/dma-mapping.h> 14 #include <linux/pm_runtime.h> 15 #include <linux/hw_random.h> 16 /* 17 * Note that according to the algorithm ID, 2 versions of the TRNG exists, 18 * The first present in H3/H5/R40/A64 and the second present in H6. 19 * This file adds support for both, but only the second is working 20 * reliabily according to rngtest. 21 **/ 22 23 static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool wait) 24 { 25 struct sun8i_ce_dev *ce; 26 dma_addr_t dma_dst; 27 int err = 0; 28 int flow = 3; 29 unsigned int todo; 30 struct sun8i_ce_flow *chan; 31 struct ce_task *cet; 32 u32 common; 33 void *d; 34 35 ce = container_of(rng, struct sun8i_ce_dev, trng); 36 37 /* round the data length to a multiple of 32*/ 38 todo = max + 32; 39 todo -= todo % 32; 40 41 d = kzalloc(todo, GFP_KERNEL | GFP_DMA); 42 if (!d) 43 return -ENOMEM; 44 45 #ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG 46 ce->hwrng_stat_req++; 47 ce->hwrng_stat_bytes += todo; 48 #endif 49 50 dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE); 51 if (dma_mapping_error(ce->dev, dma_dst)) { 52 dev_err(ce->dev, "Cannot DMA MAP DST\n"); 53 err = -EFAULT; 54 goto err_dst; 55 } 56 57 err = pm_runtime_get_sync(ce->dev); 58 if (err < 0) { 59 pm_runtime_put_noidle(ce->dev); 60 goto err_pm; 61 } 62 63 mutex_lock(&ce->rnglock); 64 chan = &ce->chanlist[flow]; 65 66 cet = &chan->tl[0]; 67 memset(cet, 0, sizeof(struct ce_task)); 68 69 cet->t_id = cpu_to_le32(flow); 70 common = ce->variant->trng | CE_COMM_INT; 71 cet->t_common_ctl = cpu_to_le32(common); 72 73 /* recent CE (H6) need length in bytes, in word otherwise */ 74 if (ce->variant->trng_t_dlen_in_bytes) 75 cet->t_dlen = cpu_to_le32(todo); 76 else 77 cet->t_dlen = cpu_to_le32(todo / 4); 78 79 cet->t_sym_ctl = 0; 80 cet->t_asym_ctl = 0; 81 82 cet->t_dst[0].addr = cpu_to_le32(dma_dst); 83 cet->t_dst[0].len = cpu_to_le32(todo / 4); 84 ce->chanlist[flow].timeout = todo; 85 86 err = sun8i_ce_run_task(ce, 3, "TRNG"); 87 mutex_unlock(&ce->rnglock); 88 89 pm_runtime_put(ce->dev); 90 91 err_pm: 92 dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE); 93 94 if (!err) { 95 memcpy(data, d, max); 96 err = max; 97 } 98 err_dst: 99 kfree_sensitive(d); 100 return err; 101 } 102 103 int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce) 104 { 105 int ret; 106 107 if (ce->variant->trng == CE_ID_NOTSUPP) { 108 dev_info(ce->dev, "TRNG not supported\n"); 109 return 0; 110 } 111 ce->trng.name = "sun8i Crypto Engine TRNG"; 112 ce->trng.read = sun8i_ce_trng_read; 113 ce->trng.quality = 1000; 114 115 ret = hwrng_register(&ce->trng); 116 if (ret) 117 dev_err(ce->dev, "Fail to register the TRNG\n"); 118 return ret; 119 } 120 121 void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce) 122 { 123 if (ce->variant->trng == CE_ID_NOTSUPP) 124 return; 125 hwrng_unregister(&ce->trng); 126 } 127