drivers/crypto/hisilicon/trng/trng.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /* Copyright (c) 2019 HiSilicon Limited. */

 #include <linux/acpi.h>
 #include <linux/crypto.h>
 #include <linux/err.h>
 #include <linux/hw_random.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/random.h>
 #include <crypto/internal/rng.h>

 #define HISI_TRNG_REG		0x00F0
 #define HISI_TRNG_BYTES		4
 #define HISI_TRNG_QUALITY	512
 #define HISI_TRNG_VERSION	0x01B8
 #define HISI_TRNG_VER_V1	GENMASK(31, 0)
 #define SLEEP_US		10
 #define TIMEOUT_US		10000
 #define SW_DRBG_NUM_SHIFT	2
 #define SW_DRBG_KEY_BASE	0x082C
 #define SW_DRBG_SEED(n)         (SW_DRBG_KEY_BASE - ((n) << SW_DRBG_NUM_SHIFT))
 #define SW_DRBG_SEED_REGS_NUM	12
 #define SW_DRBG_SEED_SIZE	48
 #define SW_DRBG_BLOCKS		0x0830
 #define SW_DRBG_INIT		0x0834
 #define SW_DRBG_GEN		0x083c
 #define SW_DRBG_STATUS		0x0840
 #define SW_DRBG_BLOCKS_NUM	4095
 #define SW_DRBG_DATA_BASE	0x0850
 #define SW_DRBG_DATA_NUM	4
 #define SW_DRBG_DATA(n)		(SW_DRBG_DATA_BASE - ((n) << SW_DRBG_NUM_SHIFT))
 #define SW_DRBG_BYTES		16
 #define SW_DRBG_ENABLE_SHIFT	12
 #define SEED_SHIFT_24		24
 #define SEED_SHIFT_16		16
 #define SEED_SHIFT_8		8

 struct hisi_trng_list {
 	struct mutex lock;
 	struct list_head list;
 	bool is_init;
 };

 struct hisi_trng {
 	void __iomem *base;
 	struct hisi_trng_list *trng_list;
 	struct list_head list;
 	struct hwrng rng;
 	u32 ver;
 	bool is_used;
 	struct mutex mutex;
 };

 struct hisi_trng_ctx {
 	struct hisi_trng *trng;
 };

 static atomic_t trng_active_devs;
 static struct hisi_trng_list trng_devices;

 static void hisi_trng_set_seed(struct hisi_trng *trng, const u8 *seed)
 {
 	u32 val, seed_reg, i;

 	for (i = 0; i < SW_DRBG_SEED_SIZE;
 	     i += SW_DRBG_SEED_SIZE / SW_DRBG_SEED_REGS_NUM) {
 		val = seed[i] << SEED_SHIFT_24;
 		val |= seed[i + 1UL] << SEED_SHIFT_16;
 		val |= seed[i + 2UL] << SEED_SHIFT_8;
 		val |= seed[i + 3UL];

 		seed_reg = (i >> SW_DRBG_NUM_SHIFT) % SW_DRBG_SEED_REGS_NUM;
 		writel(val, trng->base + SW_DRBG_SEED(seed_reg));
 	}
 }

 static int hisi_trng_seed(struct crypto_rng *tfm, const u8 *seed,
 			  unsigned int slen)
 {
 	struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
 	struct hisi_trng *trng = ctx->trng;
 	u32 val = 0;
 	int ret = 0;

 	if (slen < SW_DRBG_SEED_SIZE) {
 		pr_err("slen(%u) is not matched with trng(%d)\n", slen,
 			SW_DRBG_SEED_SIZE);
 		return -EINVAL;
 	}

 	writel(0x0, trng->base + SW_DRBG_BLOCKS);
 	hisi_trng_set_seed(trng, seed);

 	writel(SW_DRBG_BLOCKS_NUM | (0x1 << SW_DRBG_ENABLE_SHIFT),
 	       trng->base + SW_DRBG_BLOCKS);
 	writel(0x1, trng->base + SW_DRBG_INIT);

 	ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
 					val, val & BIT(0), SLEEP_US, TIMEOUT_US);
 	if (ret)
 		pr_err("fail to init trng(%d)\n", ret);

 	return ret;
 }

 static int hisi_trng_generate(struct crypto_rng *tfm, const u8 *src,
 			      unsigned int slen, u8 *dstn, unsigned int dlen)
 {
 	struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
 	struct hisi_trng *trng = ctx->trng;
 	u32 data[SW_DRBG_DATA_NUM];
 	u32 currsize = 0;
 	u32 val = 0;
 	int ret;
 	u32 i;

 	if (dlen > SW_DRBG_BLOCKS_NUM * SW_DRBG_BYTES || dlen == 0) {
 		pr_err("dlen(%d) exceeds limit(%d)!\n", dlen,
 			SW_DRBG_BLOCKS_NUM * SW_DRBG_BYTES);
 		return -EINVAL;
 	}

 	do {
 		ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
 		     val, val & BIT(1), SLEEP_US, TIMEOUT_US);
 		if (ret) {
 			pr_err("fail to generate random number(%d)!\n", ret);
 			break;
 		}

 		for (i = 0; i < SW_DRBG_DATA_NUM; i++)
 			data[i] = readl(trng->base + SW_DRBG_DATA(i));

 		if (dlen - currsize >= SW_DRBG_BYTES) {
 			memcpy(dstn + currsize, data, SW_DRBG_BYTES);
 			currsize += SW_DRBG_BYTES;
 		} else {
 			memcpy(dstn + currsize, data, dlen - currsize);
 			currsize = dlen;
 		}

 		writel(0x1, trng->base + SW_DRBG_GEN);
 	} while (currsize < dlen);

 	return ret;
 }

 static int hisi_trng_init(struct crypto_tfm *tfm)
 {
 	struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);
 	struct hisi_trng *trng;
 	int ret = -EBUSY;

 	mutex_lock(&trng_devices.lock);
 	list_for_each_entry(trng, &trng_devices.list, list) {
 		if (!trng->is_used) {
 			trng->is_used = true;
 			ctx->trng = trng;
 			ret = 0;
 			break;
 		}
 	}
 	mutex_unlock(&trng_devices.lock);

 	return ret;
 }

 static void hisi_trng_exit(struct crypto_tfm *tfm)
 {
 	struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);

 	mutex_lock(&trng_devices.lock);
 	ctx->trng->is_used = false;
 	mutex_unlock(&trng_devices.lock);
 }

 static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 {
 	struct hisi_trng *trng;
 	int currsize = 0;
 	u32 val = 0;
 	int ret;

 	trng = container_of(rng, struct hisi_trng, rng);

 	do {
 		ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val,
 					 val, SLEEP_US, TIMEOUT_US);
 		if (ret)
 			return currsize;

 		if (max - currsize >= HISI_TRNG_BYTES) {
 			memcpy(buf + currsize, &val, HISI_TRNG_BYTES);
 			currsize += HISI_TRNG_BYTES;
 			if (currsize == max)
 				return currsize;
 			continue;
 		}

 		/* copy remaining bytes */
 		memcpy(buf + currsize, &val, max - currsize);
 		currsize = max;
 	} while (currsize < max);

 	return currsize;
 }

 static struct rng_alg hisi_trng_alg = {
 	.generate = hisi_trng_generate,
 	.seed =	hisi_trng_seed,
 	.seedsize = SW_DRBG_SEED_SIZE,
 	.base = {
 		.cra_name = "stdrng",
 		.cra_driver_name = "hisi_stdrng",
 		.cra_priority = 300,
 		.cra_ctxsize = sizeof(struct hisi_trng_ctx),
 		.cra_module = THIS_MODULE,
 		.cra_init = hisi_trng_init,
 		.cra_exit = hisi_trng_exit,
 	},
 };

 static void hisi_trng_add_to_list(struct hisi_trng *trng)
 {
 	mutex_lock(&trng_devices.lock);
 	list_add_tail(&trng->list, &trng_devices.list);
 	mutex_unlock(&trng_devices.lock);
 }

 static int hisi_trng_del_from_list(struct hisi_trng *trng)
 {
 	int ret = -EBUSY;

 	mutex_lock(&trng_devices.lock);
 	if (!trng->is_used) {
 		list_del(&trng->list);
 		ret = 0;
 	}
 	mutex_unlock(&trng_devices.lock);

 	return ret;
 }

 static int hisi_trng_probe(struct platform_device *pdev)
 {
 	struct hisi_trng *trng;
 	int ret;

 	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
 	if (!trng)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, trng);

 	trng->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(trng->base))
 		return PTR_ERR(trng->base);

 	trng->is_used = false;
 	trng->ver = readl(trng->base + HISI_TRNG_VERSION);
 	if (!trng_devices.is_init) {
 		INIT_LIST_HEAD(&trng_devices.list);
 		mutex_init(&trng_devices.lock);
 		trng_devices.is_init = true;
 	}

 	hisi_trng_add_to_list(trng);
 	if (trng->ver != HISI_TRNG_VER_V1 &&
 	    atomic_inc_return(&trng_active_devs) == 1) {
 		ret = crypto_register_rng(&hisi_trng_alg);
 		if (ret) {
 			dev_err(&pdev->dev,
 				"failed to register crypto(%d)\n", ret);
 			atomic_dec_return(&trng_active_devs);
 			goto err_remove_from_list;
 		}
 	}

 	trng->rng.name = pdev->name;
 	trng->rng.read = hisi_trng_read;
 	trng->rng.quality = HISI_TRNG_QUALITY;
 	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register hwrng: %d!\n", ret);
 		goto err_crypto_unregister;
 	}

 	return ret;

 err_crypto_unregister:
 	if (trng->ver != HISI_TRNG_VER_V1 &&
 	    atomic_dec_return(&trng_active_devs) == 0)
 		crypto_unregister_rng(&hisi_trng_alg);

 err_remove_from_list:
 	hisi_trng_del_from_list(trng);
 	return ret;
 }

 static void hisi_trng_remove(struct platform_device *pdev)
 {
 	struct hisi_trng *trng = platform_get_drvdata(pdev);

 	/* Wait until the task is finished */
 	while (hisi_trng_del_from_list(trng))
 		;

 	if (trng->ver != HISI_TRNG_VER_V1 &&
 	    atomic_dec_return(&trng_active_devs) == 0)
 		crypto_unregister_rng(&hisi_trng_alg);
 }

 static const struct acpi_device_id hisi_trng_acpi_match[] = {
 	{ "HISI02B3", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);

 static struct platform_driver hisi_trng_driver = {
 	.probe		= hisi_trng_probe,
 	.remove_new     = hisi_trng_remove,
 	.driver		= {
 		.name	= "hisi-trng-v2",
 		.acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
 	},
 };

 module_platform_driver(hisi_trng_driver);

 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
 MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
 MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");
	// SPDX-License-Identifier: GPL-2.0
	/* Copyright (c) 2019 HiSilicon Limited. */

	#include <linux/acpi.h>
	#include <linux/crypto.h>
	#include <linux/err.h>
	#include <linux/hw_random.h>
	#include <linux/io.h>
	#include <linux/iopoll.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/platform_device.h>
	#include <linux/random.h>
	#include <crypto/internal/rng.h>

	#define HISI_TRNG_REG 0x00F0
	#define HISI_TRNG_BYTES 4
	#define HISI_TRNG_QUALITY 512
	#define HISI_TRNG_VERSION 0x01B8
	#define HISI_TRNG_VER_V1 GENMASK(31, 0)
	#define SLEEP_US 10
	#define TIMEOUT_US 10000
	#define SW_DRBG_NUM_SHIFT 2
	#define SW_DRBG_KEY_BASE 0x082C
	#define SW_DRBG_SEED(n) (SW_DRBG_KEY_BASE - ((n) << SW_DRBG_NUM_SHIFT))
	#define SW_DRBG_SEED_REGS_NUM 12
	#define SW_DRBG_SEED_SIZE 48
	#define SW_DRBG_BLOCKS 0x0830
	#define SW_DRBG_INIT 0x0834
	#define SW_DRBG_GEN 0x083c
	#define SW_DRBG_STATUS 0x0840
	#define SW_DRBG_BLOCKS_NUM 4095
	#define SW_DRBG_DATA_BASE 0x0850
	#define SW_DRBG_DATA_NUM 4
	#define SW_DRBG_DATA(n) (SW_DRBG_DATA_BASE - ((n) << SW_DRBG_NUM_SHIFT))
	#define SW_DRBG_BYTES 16
	#define SW_DRBG_ENABLE_SHIFT 12
	#define SEED_SHIFT_24 24
	#define SEED_SHIFT_16 16
	#define SEED_SHIFT_8 8

	struct hisi_trng_list {
	struct mutex lock;
	struct list_head list;
	bool is_init;
	};

	struct hisi_trng {
	void __iomem *base;
	struct hisi_trng_list *trng_list;
	struct list_head list;
	struct hwrng rng;
	u32 ver;
	bool is_used;
	struct mutex mutex;
	};

	struct hisi_trng_ctx {
	struct hisi_trng *trng;
	};

	static atomic_t trng_active_devs;
	static struct hisi_trng_list trng_devices;

	static void hisi_trng_set_seed(struct hisi_trng trng, const u8 seed)
	{
	u32 val, seed_reg, i;

	for (i = 0; i < SW_DRBG_SEED_SIZE;
	i += SW_DRBG_SEED_SIZE / SW_DRBG_SEED_REGS_NUM) {
	val = seed[i] << SEED_SHIFT_24;
	val \|= seed[i + 1UL] << SEED_SHIFT_16;
	val \|= seed[i + 2UL] << SEED_SHIFT_8;
	val \|= seed[i + 3UL];

	seed_reg = (i >> SW_DRBG_NUM_SHIFT) % SW_DRBG_SEED_REGS_NUM;
	writel(val, trng->base + SW_DRBG_SEED(seed_reg));
	}
	}

	static int hisi_trng_seed(struct crypto_rng tfm, const u8 seed,
	unsigned int slen)
	{
	struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
	struct hisi_trng *trng = ctx->trng;
	u32 val = 0;
	int ret = 0;

	if (slen < SW_DRBG_SEED_SIZE) {
	pr_err("slen(%u) is not matched with trng(%d)\n", slen,
	SW_DRBG_SEED_SIZE);
	return -EINVAL;
	}

	writel(0x0, trng->base + SW_DRBG_BLOCKS);
	hisi_trng_set_seed(trng, seed);

	writel(SW_DRBG_BLOCKS_NUM \| (0x1 << SW_DRBG_ENABLE_SHIFT),
	trng->base + SW_DRBG_BLOCKS);
	writel(0x1, trng->base + SW_DRBG_INIT);

	ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
	val, val & BIT(0), SLEEP_US, TIMEOUT_US);
	if (ret)
	pr_err("fail to init trng(%d)\n", ret);

	return ret;
	}

	static int hisi_trng_generate(struct crypto_rng tfm, const u8 src,
	unsigned int slen, u8 *dstn, unsigned int dlen)
	{
	struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
	struct hisi_trng *trng = ctx->trng;
	u32 data[SW_DRBG_DATA_NUM];
	u32 currsize = 0;
	u32 val = 0;
	int ret;
	u32 i;

	if (dlen > SW_DRBG_BLOCKS_NUM * SW_DRBG_BYTES \|\| dlen == 0) {
	pr_err("dlen(%d) exceeds limit(%d)!\n", dlen,
	SW_DRBG_BLOCKS_NUM * SW_DRBG_BYTES);
	return -EINVAL;
	}

	do {
	ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
	val, val & BIT(1), SLEEP_US, TIMEOUT_US);
	if (ret) {
	pr_err("fail to generate random number(%d)!\n", ret);
	break;
	}

	for (i = 0; i < SW_DRBG_DATA_NUM; i++)
	data[i] = readl(trng->base + SW_DRBG_DATA(i));

	if (dlen - currsize >= SW_DRBG_BYTES) {
	memcpy(dstn + currsize, data, SW_DRBG_BYTES);
	currsize += SW_DRBG_BYTES;
	} else {
	memcpy(dstn + currsize, data, dlen - currsize);
	currsize = dlen;
	}

	writel(0x1, trng->base + SW_DRBG_GEN);
	} while (currsize < dlen);

	return ret;
	}

	static int hisi_trng_init(struct crypto_tfm *tfm)
	{
	struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);
	struct hisi_trng *trng;
	int ret = -EBUSY;

	mutex_lock(&trng_devices.lock);
	list_for_each_entry(trng, &trng_devices.list, list) {
	if (!trng->is_used) {
	trng->is_used = true;
	ctx->trng = trng;
	ret = 0;
	break;
	}
	}
	mutex_unlock(&trng_devices.lock);

	return ret;
	}

	static void hisi_trng_exit(struct crypto_tfm *tfm)
	{
	struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);

	mutex_lock(&trng_devices.lock);
	ctx->trng->is_used = false;
	mutex_unlock(&trng_devices.lock);
	}

	static int hisi_trng_read(struct hwrng rng, void buf, size_t max, bool wait)
	{
	struct hisi_trng *trng;
	int currsize = 0;
	u32 val = 0;
	int ret;

	trng = container_of(rng, struct hisi_trng, rng);

	do {
	ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val,
	val, SLEEP_US, TIMEOUT_US);
	if (ret)
	return currsize;

	if (max - currsize >= HISI_TRNG_BYTES) {
	memcpy(buf + currsize, &val, HISI_TRNG_BYTES);
	currsize += HISI_TRNG_BYTES;
	if (currsize == max)
	return currsize;
	continue;
	}

	/* copy remaining bytes */
	memcpy(buf + currsize, &val, max - currsize);
	currsize = max;
	} while (currsize < max);

	return currsize;
	}

	static struct rng_alg hisi_trng_alg = {
	.generate = hisi_trng_generate,
	.seed = hisi_trng_seed,
	.seedsize = SW_DRBG_SEED_SIZE,
	.base = {
	.cra_name = "stdrng",
	.cra_driver_name = "hisi_stdrng",
	.cra_priority = 300,
	.cra_ctxsize = sizeof(struct hisi_trng_ctx),
	.cra_module = THIS_MODULE,
	.cra_init = hisi_trng_init,
	.cra_exit = hisi_trng_exit,
	},
	};

	static void hisi_trng_add_to_list(struct hisi_trng *trng)
	{
	mutex_lock(&trng_devices.lock);
	list_add_tail(&trng->list, &trng_devices.list);
	mutex_unlock(&trng_devices.lock);
	}

	static int hisi_trng_del_from_list(struct hisi_trng *trng)
	{
	int ret = -EBUSY;

	mutex_lock(&trng_devices.lock);
	if (!trng->is_used) {
	list_del(&trng->list);
	ret = 0;
	}
	mutex_unlock(&trng_devices.lock);

	return ret;
	}

	static int hisi_trng_probe(struct platform_device *pdev)
	{
	struct hisi_trng *trng;
	int ret;

	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
	if (!trng)
	return -ENOMEM;

	platform_set_drvdata(pdev, trng);

	trng->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(trng->base))
	return PTR_ERR(trng->base);

	trng->is_used = false;
	trng->ver = readl(trng->base + HISI_TRNG_VERSION);
	if (!trng_devices.is_init) {
	INIT_LIST_HEAD(&trng_devices.list);
	mutex_init(&trng_devices.lock);
	trng_devices.is_init = true;
	}

	hisi_trng_add_to_list(trng);
	if (trng->ver != HISI_TRNG_VER_V1 &&
	atomic_inc_return(&trng_active_devs) == 1) {
	ret = crypto_register_rng(&hisi_trng_alg);
	if (ret) {
	dev_err(&pdev->dev,
	"failed to register crypto(%d)\n", ret);
	atomic_dec_return(&trng_active_devs);
	goto err_remove_from_list;
	}
	}

	trng->rng.name = pdev->name;
	trng->rng.read = hisi_trng_read;
	trng->rng.quality = HISI_TRNG_QUALITY;
	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
	if (ret) {
	dev_err(&pdev->dev, "failed to register hwrng: %d!\n", ret);
	goto err_crypto_unregister;
	}

	return ret;

	err_crypto_unregister:
	if (trng->ver != HISI_TRNG_VER_V1 &&
	atomic_dec_return(&trng_active_devs) == 0)
	crypto_unregister_rng(&hisi_trng_alg);

	err_remove_from_list:
	hisi_trng_del_from_list(trng);
	return ret;
	}

	static void hisi_trng_remove(struct platform_device *pdev)
	{
	struct hisi_trng *trng = platform_get_drvdata(pdev);

	/* Wait until the task is finished */
	while (hisi_trng_del_from_list(trng))
	;

	if (trng->ver != HISI_TRNG_VER_V1 &&
	atomic_dec_return(&trng_active_devs) == 0)
	crypto_unregister_rng(&hisi_trng_alg);
	}

	static const struct acpi_device_id hisi_trng_acpi_match[] = {
	{ "HISI02B3", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);

	static struct platform_driver hisi_trng_driver = {
	.probe = hisi_trng_probe,
	.remove_new = hisi_trng_remove,
	.driver = {
	.name = "hisi-trng-v2",
	.acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
	},
	};

	module_platform_driver(hisi_trng_driver);

	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
	MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
	MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");