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1// SPDX-License-Identifier: GPL-2.02// Copyright (c) 2017-18 Linaro Limited3//4// Based on msm-rng.c and downstream driver5 6#include <crypto/internal/rng.h>7#include <linux/acpi.h>8#include <linux/clk.h>9#include <linux/crypto.h>10#include <linux/hw_random.h>11#include <linux/io.h>12#include <linux/iopoll.h>13#include <linux/kernel.h>14#include <linux/module.h>15#include <linux/of.h>16#include <linux/platform_device.h>17 18/* Device specific register offsets */19#define PRNG_DATA_OUT 0x000020#define PRNG_STATUS 0x000421#define PRNG_LFSR_CFG 0x010022#define PRNG_CONFIG 0x010423 24/* Device specific register masks and config values */25#define PRNG_LFSR_CFG_MASK 0x0000ffff26#define PRNG_LFSR_CFG_CLOCKS 0x0000dddd27#define PRNG_CONFIG_HW_ENABLE BIT(1)28#define PRNG_STATUS_DATA_AVAIL BIT(0)29 30#define WORD_SZ 431 32#define QCOM_TRNG_QUALITY 102433 34struct qcom_rng {35 struct mutex lock;36 void __iomem *base;37 struct clk *clk;38 struct hwrng hwrng;39 struct qcom_rng_match_data *match_data;40};41 42struct qcom_rng_ctx {43 struct qcom_rng *rng;44};45 46struct qcom_rng_match_data {47 bool skip_init;48 bool hwrng_support;49};50 51static struct qcom_rng *qcom_rng_dev;52 53static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)54{55 unsigned int currsize = 0;56 u32 val;57 int ret;58 59 /* read random data from hardware */60 do {61 ret = readl_poll_timeout(rng->base + PRNG_STATUS, val,62 val & PRNG_STATUS_DATA_AVAIL,63 200, 10000);64 if (ret)65 return ret;66 67 val = readl_relaxed(rng->base + PRNG_DATA_OUT);68 if (!val)69 return -EINVAL;70 71 if ((max - currsize) >= WORD_SZ) {72 memcpy(data, &val, WORD_SZ);73 data += WORD_SZ;74 currsize += WORD_SZ;75 } else {76 /* copy only remaining bytes */77 memcpy(data, &val, max - currsize);78 currsize = max;79 }80 } while (currsize < max);81 82 return currsize;83}84 85static int qcom_rng_generate(struct crypto_rng *tfm,86 const u8 *src, unsigned int slen,87 u8 *dstn, unsigned int dlen)88{89 struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm);90 struct qcom_rng *rng = ctx->rng;91 int ret;92 93 ret = clk_prepare_enable(rng->clk);94 if (ret)95 return ret;96 97 mutex_lock(&rng->lock);98 99 ret = qcom_rng_read(rng, dstn, dlen);100 101 mutex_unlock(&rng->lock);102 clk_disable_unprepare(rng->clk);103 104 if (ret >= 0)105 ret = 0;106 107 return ret;108}109 110static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,111 unsigned int slen)112{113 return 0;114}115 116static int qcom_hwrng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)117{118 struct qcom_rng *qrng = container_of(hwrng, struct qcom_rng, hwrng);119 120 return qcom_rng_read(qrng, data, max);121}122 123static int qcom_rng_enable(struct qcom_rng *rng)124{125 u32 val;126 int ret;127 128 ret = clk_prepare_enable(rng->clk);129 if (ret)130 return ret;131 132 /* Enable PRNG only if it is not already enabled */133 val = readl_relaxed(rng->base + PRNG_CONFIG);134 if (val & PRNG_CONFIG_HW_ENABLE)135 goto already_enabled;136 137 val = readl_relaxed(rng->base + PRNG_LFSR_CFG);138 val &= ~PRNG_LFSR_CFG_MASK;139 val |= PRNG_LFSR_CFG_CLOCKS;140 writel(val, rng->base + PRNG_LFSR_CFG);141 142 val = readl_relaxed(rng->base + PRNG_CONFIG);143 val |= PRNG_CONFIG_HW_ENABLE;144 writel(val, rng->base + PRNG_CONFIG);145 146already_enabled:147 clk_disable_unprepare(rng->clk);148 149 return 0;150}151 152static int qcom_rng_init(struct crypto_tfm *tfm)153{154 struct qcom_rng_ctx *ctx = crypto_tfm_ctx(tfm);155 156 ctx->rng = qcom_rng_dev;157 158 if (!ctx->rng->match_data->skip_init)159 return qcom_rng_enable(ctx->rng);160 161 return 0;162}163 164static struct rng_alg qcom_rng_alg = {165 .generate = qcom_rng_generate,166 .seed = qcom_rng_seed,167 .seedsize = 0,168 .base = {169 .cra_name = "stdrng",170 .cra_driver_name = "qcom-rng",171 .cra_flags = CRYPTO_ALG_TYPE_RNG,172 .cra_priority = 300,173 .cra_ctxsize = sizeof(struct qcom_rng_ctx),174 .cra_module = THIS_MODULE,175 .cra_init = qcom_rng_init,176 }177};178 179static int qcom_rng_probe(struct platform_device *pdev)180{181 struct qcom_rng *rng;182 int ret;183 184 rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);185 if (!rng)186 return -ENOMEM;187 188 platform_set_drvdata(pdev, rng);189 mutex_init(&rng->lock);190 191 rng->base = devm_platform_ioremap_resource(pdev, 0);192 if (IS_ERR(rng->base))193 return PTR_ERR(rng->base);194 195 rng->clk = devm_clk_get_optional(&pdev->dev, "core");196 if (IS_ERR(rng->clk))197 return PTR_ERR(rng->clk);198 199 rng->match_data = (struct qcom_rng_match_data *)device_get_match_data(&pdev->dev);200 201 qcom_rng_dev = rng;202 ret = crypto_register_rng(&qcom_rng_alg);203 if (ret) {204 dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret);205 qcom_rng_dev = NULL;206 return ret;207 }208 209 if (rng->match_data->hwrng_support) {210 rng->hwrng.name = "qcom_hwrng";211 rng->hwrng.read = qcom_hwrng_read;212 rng->hwrng.quality = QCOM_TRNG_QUALITY;213 ret = devm_hwrng_register(&pdev->dev, &rng->hwrng);214 if (ret) {215 dev_err(&pdev->dev, "Register hwrng failed: %d\n", ret);216 qcom_rng_dev = NULL;217 goto fail;218 }219 }220 221 return ret;222fail:223 crypto_unregister_rng(&qcom_rng_alg);224 return ret;225}226 227static void qcom_rng_remove(struct platform_device *pdev)228{229 crypto_unregister_rng(&qcom_rng_alg);230 231 qcom_rng_dev = NULL;232}233 234static struct qcom_rng_match_data qcom_prng_match_data = {235 .skip_init = false,236 .hwrng_support = false,237};238 239static struct qcom_rng_match_data qcom_prng_ee_match_data = {240 .skip_init = true,241 .hwrng_support = false,242};243 244static struct qcom_rng_match_data qcom_trng_match_data = {245 .skip_init = true,246 .hwrng_support = true,247};248 249static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = {250 { .id = "QCOM8160", .driver_data = (kernel_ulong_t)&qcom_prng_ee_match_data },251 {}252};253MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match);254 255static const struct of_device_id __maybe_unused qcom_rng_of_match[] = {256 { .compatible = "qcom,prng", .data = &qcom_prng_match_data },257 { .compatible = "qcom,prng-ee", .data = &qcom_prng_ee_match_data },258 { .compatible = "qcom,trng", .data = &qcom_trng_match_data },259 {}260};261MODULE_DEVICE_TABLE(of, qcom_rng_of_match);262 263static struct platform_driver qcom_rng_driver = {264 .probe = qcom_rng_probe,265 .remove_new = qcom_rng_remove,266 .driver = {267 .name = KBUILD_MODNAME,268 .of_match_table = of_match_ptr(qcom_rng_of_match),269 .acpi_match_table = ACPI_PTR(qcom_rng_acpi_match),270 }271};272module_platform_driver(qcom_rng_driver);273 274MODULE_ALIAS("platform:" KBUILD_MODNAME);275MODULE_DESCRIPTION("Qualcomm random number generator driver");276MODULE_LICENSE("GPL v2");277