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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 | // SPDX-License-Identifier: GPL-2.0 /* Marvell CN10K RVU Hardware Random Number Generator. * * Copyright (C) 2021 Marvell. * */ #include <linux/hw_random.h> #include <linux/io.h> #include <linux/module.h> #include <linux/pci.h> #include <linux/pci_ids.h> #include <linux/delay.h> #include <linux/arm-smccc.h> /* CSRs */ #define RNM_CTL_STATUS 0x000 #define RNM_ENTROPY_STATUS 0x008 #define RNM_CONST 0x030 #define RNM_EBG_ENT 0x048 #define RNM_PF_EBG_HEALTH 0x050 #define RNM_PF_RANDOM 0x400 #define RNM_TRNG_RESULT 0x408 struct cn10k_rng { void __iomem *reg_base; struct hwrng ops; struct pci_dev *pdev; }; #define PLAT_OCTEONTX_RESET_RNG_EBG_HEALTH_STATE 0xc2000b0f static unsigned long reset_rng_health_state(struct cn10k_rng *rng) { struct arm_smccc_res res; /* Send SMC service call to reset EBG health state */ arm_smccc_smc(PLAT_OCTEONTX_RESET_RNG_EBG_HEALTH_STATE, 0, 0, 0, 0, 0, 0, 0, &res); return res.a0; } static int check_rng_health(struct cn10k_rng *rng) { u64 status; unsigned long err; /* Skip checking health */ if (!rng->reg_base) return -ENODEV; status = readq(rng->reg_base + RNM_PF_EBG_HEALTH); if (status & BIT_ULL(20)) { err = reset_rng_health_state(rng); if (err) { dev_err(&rng->pdev->dev, "HWRNG: Health test failed (status=%llx)\n", status); dev_err(&rng->pdev->dev, "HWRNG: error during reset (error=%lx)\n", err); return -EIO; } } return 0; } static void cn10k_read_trng(struct cn10k_rng *rng, u64 *value) { u64 upper, lower; *value = readq(rng->reg_base + RNM_PF_RANDOM); /* HW can run out of entropy if large amount random data is read in * quick succession. Zeros may not be real random data from HW. */ if (!*value) { upper = readq(rng->reg_base + RNM_PF_RANDOM); lower = readq(rng->reg_base + RNM_PF_RANDOM); while (!(upper & 0x00000000FFFFFFFFULL)) upper = readq(rng->reg_base + RNM_PF_RANDOM); while (!(lower & 0xFFFFFFFF00000000ULL)) lower = readq(rng->reg_base + RNM_PF_RANDOM); *value = (upper & 0xFFFFFFFF00000000) | (lower & 0xFFFFFFFF); } } static int cn10k_rng_read(struct hwrng *hwrng, void *data, size_t max, bool wait) { struct cn10k_rng *rng = (struct cn10k_rng *)hwrng->priv; unsigned int size; u8 *pos = data; int err = 0; u64 value; err = check_rng_health(rng); if (err) return err; size = max; while (size >= 8) { cn10k_read_trng(rng, &value); *((u64 *)pos) = value; size -= 8; pos += 8; } if (size > 0) { cn10k_read_trng(rng, &value); while (size > 0) { *pos = (u8)value; value >>= 8; size--; pos++; } } return max - size; } static int cn10k_rng_probe(struct pci_dev *pdev, const struct pci_device_id *id) { struct cn10k_rng *rng; int err; rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); if (!rng) return -ENOMEM; rng->pdev = pdev; pci_set_drvdata(pdev, rng); rng->reg_base = pcim_iomap(pdev, 0, 0); if (!rng->reg_base) { dev_err(&pdev->dev, "Error while mapping CSRs, exiting\n"); return -ENOMEM; } rng->ops.name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "cn10k-rng-%s", dev_name(&pdev->dev)); if (!rng->ops.name) return -ENOMEM; rng->ops.read = cn10k_rng_read; rng->ops.priv = (unsigned long)rng; reset_rng_health_state(rng); err = devm_hwrng_register(&pdev->dev, &rng->ops); if (err) { dev_err(&pdev->dev, "Could not register hwrng device.\n"); return err; } return 0; } static void cn10k_rng_remove(struct pci_dev *pdev) { /* Nothing to do */ } static const struct pci_device_id cn10k_rng_id_table[] = { { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xA098) }, /* RNG PF */ {0,}, }; MODULE_DEVICE_TABLE(pci, cn10k_rng_id_table); static struct pci_driver cn10k_rng_driver = { .name = "cn10k_rng", .id_table = cn10k_rng_id_table, .probe = cn10k_rng_probe, .remove = cn10k_rng_remove, }; module_pci_driver(cn10k_rng_driver); MODULE_AUTHOR("Sunil Goutham <sgoutham@marvell.com>"); MODULE_DESCRIPTION("Marvell CN10K HW RNG Driver"); MODULE_LICENSE("GPL v2"); |