drivers/crypto/stm32/stm32-crc32.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) STMicroelectronics SA 2017
  * Author: Fabien Dessenne <fabien.dessenne@st.com>
  */

 #include <linux/bitrev.h>
 #include <linux/clk.h>
 #include <linux/crc32.h>
 #include <linux/crc32poly.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>

 #include <crypto/internal/hash.h>

 #include <linux/unaligned.h>

 #define DRIVER_NAME             "stm32-crc32"
 #define CHKSUM_DIGEST_SIZE      4
 #define CHKSUM_BLOCK_SIZE       1

 /* Registers */
 #define CRC_DR                  0x00000000
 #define CRC_CR                  0x00000008
 #define CRC_INIT                0x00000010
 #define CRC_POL                 0x00000014

 /* Registers values */
 #define CRC_CR_RESET            BIT(0)
 #define CRC_CR_REV_IN_WORD      (BIT(6) | BIT(5))
 #define CRC_CR_REV_IN_BYTE      BIT(5)
 #define CRC_CR_REV_OUT          BIT(7)
 #define CRC32C_INIT_DEFAULT     0xFFFFFFFF

 #define CRC_AUTOSUSPEND_DELAY	50

 static unsigned int burst_size;
 module_param(burst_size, uint, 0644);
 MODULE_PARM_DESC(burst_size, "Select burst byte size (0 unlimited)");

 struct stm32_crc {
 	struct list_head list;
 	struct device    *dev;
 	void __iomem     *regs;
 	struct clk       *clk;
 	spinlock_t       lock;
 };

 struct stm32_crc_list {
 	struct list_head dev_list;
 	spinlock_t       lock; /* protect dev_list */
 };

 static struct stm32_crc_list crc_list = {
 	.dev_list = LIST_HEAD_INIT(crc_list.dev_list),
 	.lock     = __SPIN_LOCK_UNLOCKED(crc_list.lock),
 };

 struct stm32_crc_ctx {
 	u32 key;
 	u32 poly;
 };

 struct stm32_crc_desc_ctx {
 	u32    partial; /* crc32c: partial in first 4 bytes of that struct */
 };

 static int stm32_crc32_cra_init(struct crypto_tfm *tfm)
 {
 	struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);

 	mctx->key = 0;
 	mctx->poly = CRC32_POLY_LE;
 	return 0;
 }

 static int stm32_crc32c_cra_init(struct crypto_tfm *tfm)
 {
 	struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);

 	mctx->key = CRC32C_INIT_DEFAULT;
 	mctx->poly = CRC32C_POLY_LE;
 	return 0;
 }

 static int stm32_crc_setkey(struct crypto_shash *tfm, const u8 *key,
 			    unsigned int keylen)
 {
 	struct stm32_crc_ctx *mctx = crypto_shash_ctx(tfm);

 	if (keylen != sizeof(u32))
 		return -EINVAL;

 	mctx->key = get_unaligned_le32(key);
 	return 0;
 }

 static struct stm32_crc *stm32_crc_get_next_crc(void)
 {
 	struct stm32_crc *crc;

 	spin_lock_bh(&crc_list.lock);
 	crc = list_first_entry_or_null(&crc_list.dev_list, struct stm32_crc, list);
 	if (crc)
 		list_move_tail(&crc->list, &crc_list.dev_list);
 	spin_unlock_bh(&crc_list.lock);

 	return crc;
 }

 static int stm32_crc_init(struct shash_desc *desc)
 {
 	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
 	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 	struct stm32_crc *crc;
 	unsigned long flags;

 	crc = stm32_crc_get_next_crc();
 	if (!crc)
 		return -ENODEV;

 	pm_runtime_get_sync(crc->dev);

 	spin_lock_irqsave(&crc->lock, flags);

 	/* Reset, set key, poly and configure in bit reverse mode */
 	writel_relaxed(bitrev32(mctx->key), crc->regs + CRC_INIT);
 	writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
 	writel_relaxed(CRC_CR_RESET | CRC_CR_REV_IN_WORD | CRC_CR_REV_OUT,
 		       crc->regs + CRC_CR);

 	/* Store partial result */
 	ctx->partial = readl_relaxed(crc->regs + CRC_DR);

 	spin_unlock_irqrestore(&crc->lock, flags);

 	pm_runtime_mark_last_busy(crc->dev);
 	pm_runtime_put_autosuspend(crc->dev);

 	return 0;
 }

 static int burst_update(struct shash_desc *desc, const u8 *d8,
 			size_t length)
 {
 	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
 	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 	struct stm32_crc *crc;

 	crc = stm32_crc_get_next_crc();
 	if (!crc)
 		return -ENODEV;

 	pm_runtime_get_sync(crc->dev);

 	if (!spin_trylock(&crc->lock)) {
 		/* Hardware is busy, calculate crc32 by software */
 		if (mctx->poly == CRC32_POLY_LE)
 			ctx->partial = crc32_le(ctx->partial, d8, length);
 		else
 			ctx->partial = __crc32c_le(ctx->partial, d8, length);

 		goto pm_out;
 	}

 	/*
 	 * Restore previously calculated CRC for this context as init value
 	 * Restore polynomial configuration
 	 * Configure in register for word input data,
 	 * Configure out register in reversed bit mode data.
 	 */
 	writel_relaxed(bitrev32(ctx->partial), crc->regs + CRC_INIT);
 	writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
 	writel_relaxed(CRC_CR_RESET | CRC_CR_REV_IN_WORD | CRC_CR_REV_OUT,
 		       crc->regs + CRC_CR);

 	if (d8 != PTR_ALIGN(d8, sizeof(u32))) {
 		/* Configure for byte data */
 		writel_relaxed(CRC_CR_REV_IN_BYTE | CRC_CR_REV_OUT,
 			       crc->regs + CRC_CR);
 		while (d8 != PTR_ALIGN(d8, sizeof(u32)) && length) {
 			writeb_relaxed(*d8++, crc->regs + CRC_DR);
 			length--;
 		}
 		/* Configure for word data */
 		writel_relaxed(CRC_CR_REV_IN_WORD | CRC_CR_REV_OUT,
 			       crc->regs + CRC_CR);
 	}

 	for (; length >= sizeof(u32); d8 += sizeof(u32), length -= sizeof(u32))
 		writel_relaxed(*((u32 *)d8), crc->regs + CRC_DR);

 	if (length) {
 		/* Configure for byte data */
 		writel_relaxed(CRC_CR_REV_IN_BYTE | CRC_CR_REV_OUT,
 			       crc->regs + CRC_CR);
 		while (length--)
 			writeb_relaxed(*d8++, crc->regs + CRC_DR);
 	}

 	/* Store partial result */
 	ctx->partial = readl_relaxed(crc->regs + CRC_DR);

 	spin_unlock(&crc->lock);

 pm_out:
 	pm_runtime_mark_last_busy(crc->dev);
 	pm_runtime_put_autosuspend(crc->dev);

 	return 0;
 }

 static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
 			    unsigned int length)
 {
 	const unsigned int burst_sz = burst_size;
 	unsigned int rem_sz;
 	const u8 *cur;
 	size_t size;
 	int ret;

 	if (!burst_sz)
 		return burst_update(desc, d8, length);

 	/* Digest first bytes not 32bit aligned at first pass in the loop */
 	size = min_t(size_t, length, burst_sz + (size_t)d8 -
 				     ALIGN_DOWN((size_t)d8, sizeof(u32)));
 	for (rem_sz = length, cur = d8; rem_sz;
 	     rem_sz -= size, cur += size, size = min(rem_sz, burst_sz)) {
 		ret = burst_update(desc, cur, size);
 		if (ret)
 			return ret;
 	}

 	return 0;
 }

 static int stm32_crc_final(struct shash_desc *desc, u8 *out)
 {
 	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
 	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);

 	/* Send computed CRC */
 	put_unaligned_le32(mctx->poly == CRC32C_POLY_LE ?
 			   ~ctx->partial : ctx->partial, out);

 	return 0;
 }

 static int stm32_crc_finup(struct shash_desc *desc, const u8 *data,
 			   unsigned int length, u8 *out)
 {
 	return stm32_crc_update(desc, data, length) ?:
 	       stm32_crc_final(desc, out);
 }

 static int stm32_crc_digest(struct shash_desc *desc, const u8 *data,
 			    unsigned int length, u8 *out)
 {
 	return stm32_crc_init(desc) ?: stm32_crc_finup(desc, data, length, out);
 }

 static unsigned int refcnt;
 static DEFINE_MUTEX(refcnt_lock);
 static struct shash_alg algs[] = {
 	/* CRC-32 */
 	{
 		.setkey         = stm32_crc_setkey,
 		.init           = stm32_crc_init,
 		.update         = stm32_crc_update,
 		.final          = stm32_crc_final,
 		.finup          = stm32_crc_finup,
 		.digest         = stm32_crc_digest,
 		.descsize       = sizeof(struct stm32_crc_desc_ctx),
 		.digestsize     = CHKSUM_DIGEST_SIZE,
 		.base           = {
 			.cra_name               = "crc32",
 			.cra_driver_name        = "stm32-crc32-crc32",
 			.cra_priority           = 200,
 			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
 			.cra_ctxsize            = sizeof(struct stm32_crc_ctx),
 			.cra_module             = THIS_MODULE,
 			.cra_init               = stm32_crc32_cra_init,
 		}
 	},
 	/* CRC-32Castagnoli */
 	{
 		.setkey         = stm32_crc_setkey,
 		.init           = stm32_crc_init,
 		.update         = stm32_crc_update,
 		.final          = stm32_crc_final,
 		.finup          = stm32_crc_finup,
 		.digest         = stm32_crc_digest,
 		.descsize       = sizeof(struct stm32_crc_desc_ctx),
 		.digestsize     = CHKSUM_DIGEST_SIZE,
 		.base           = {
 			.cra_name               = "crc32c",
 			.cra_driver_name        = "stm32-crc32-crc32c",
 			.cra_priority           = 200,
 			.cra_flags		= CRYPTO_ALG_OPTIONAL_KEY,
 			.cra_blocksize          = CHKSUM_BLOCK_SIZE,
 			.cra_ctxsize            = sizeof(struct stm32_crc_ctx),
 			.cra_module             = THIS_MODULE,
 			.cra_init               = stm32_crc32c_cra_init,
 		}
 	}
 };

 static int stm32_crc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct stm32_crc *crc;
 	int ret;

 	crc = devm_kzalloc(dev, sizeof(*crc), GFP_KERNEL);
 	if (!crc)
 		return -ENOMEM;

 	crc->dev = dev;

 	crc->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(crc->regs)) {
 		dev_err(dev, "Cannot map CRC IO\n");
 		return PTR_ERR(crc->regs);
 	}

 	crc->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(crc->clk)) {
 		dev_err(dev, "Could not get clock\n");
 		return PTR_ERR(crc->clk);
 	}

 	ret = clk_prepare_enable(crc->clk);
 	if (ret) {
 		dev_err(crc->dev, "Failed to enable clock\n");
 		return ret;
 	}

 	pm_runtime_set_autosuspend_delay(dev, CRC_AUTOSUSPEND_DELAY);
 	pm_runtime_use_autosuspend(dev);

 	pm_runtime_get_noresume(dev);
 	pm_runtime_set_active(dev);
 	pm_runtime_irq_safe(dev);
 	pm_runtime_enable(dev);

 	spin_lock_init(&crc->lock);

 	platform_set_drvdata(pdev, crc);

 	spin_lock(&crc_list.lock);
 	list_add(&crc->list, &crc_list.dev_list);
 	spin_unlock(&crc_list.lock);

 	mutex_lock(&refcnt_lock);
 	if (!refcnt) {
 		ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
 		if (ret) {
 			mutex_unlock(&refcnt_lock);
 			dev_err(dev, "Failed to register\n");
 			clk_disable_unprepare(crc->clk);
 			return ret;
 		}
 	}
 	refcnt++;
 	mutex_unlock(&refcnt_lock);

 	dev_info(dev, "Initialized\n");

 	pm_runtime_put_sync(dev);

 	return 0;
 }

 static void stm32_crc_remove(struct platform_device *pdev)
 {
 	struct stm32_crc *crc = platform_get_drvdata(pdev);
 	int ret = pm_runtime_get_sync(crc->dev);

 	spin_lock(&crc_list.lock);
 	list_del(&crc->list);
 	spin_unlock(&crc_list.lock);

 	mutex_lock(&refcnt_lock);
 	if (!--refcnt)
 		crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
 	mutex_unlock(&refcnt_lock);

 	pm_runtime_disable(crc->dev);
 	pm_runtime_put_noidle(crc->dev);

 	if (ret >= 0)
 		clk_disable(crc->clk);
 	clk_unprepare(crc->clk);
 }

 static int __maybe_unused stm32_crc_suspend(struct device *dev)
 {
 	struct stm32_crc *crc = dev_get_drvdata(dev);
 	int ret;

 	ret = pm_runtime_force_suspend(dev);
 	if (ret)
 		return ret;

 	clk_unprepare(crc->clk);

 	return 0;
 }

 static int __maybe_unused stm32_crc_resume(struct device *dev)
 {
 	struct stm32_crc *crc = dev_get_drvdata(dev);
 	int ret;

 	ret = clk_prepare(crc->clk);
 	if (ret) {
 		dev_err(crc->dev, "Failed to prepare clock\n");
 		return ret;
 	}

 	return pm_runtime_force_resume(dev);
 }

 static int __maybe_unused stm32_crc_runtime_suspend(struct device *dev)
 {
 	struct stm32_crc *crc = dev_get_drvdata(dev);

 	clk_disable(crc->clk);

 	return 0;
 }

 static int __maybe_unused stm32_crc_runtime_resume(struct device *dev)
 {
 	struct stm32_crc *crc = dev_get_drvdata(dev);
 	int ret;

 	ret = clk_enable(crc->clk);
 	if (ret) {
 		dev_err(crc->dev, "Failed to enable clock\n");
 		return ret;
 	}

 	return 0;
 }

 static const struct dev_pm_ops stm32_crc_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(stm32_crc_suspend,
 				stm32_crc_resume)
 	SET_RUNTIME_PM_OPS(stm32_crc_runtime_suspend,
 			   stm32_crc_runtime_resume, NULL)
 };

 static const struct of_device_id stm32_dt_ids[] = {
 	{ .compatible = "st,stm32f7-crc", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, stm32_dt_ids);

 static struct platform_driver stm32_crc_driver = {
 	.probe  = stm32_crc_probe,
 	.remove = stm32_crc_remove,
 	.driver = {
 		.name           = DRIVER_NAME,
 		.pm		= &stm32_crc_pm_ops,
 		.of_match_table = stm32_dt_ids,
 	},
 };

 module_platform_driver(stm32_crc_driver);

 MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
 MODULE_DESCRIPTION("STMicrolectronics STM32 CRC32 hardware driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) STMicroelectronics SA 2017
	* Author: Fabien Dessenne <fabien.dessenne@st.com>
	*/

	#include <linux/bitrev.h>
	#include <linux/clk.h>
	#include <linux/crc32.h>
	#include <linux/crc32poly.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>

	#include <crypto/internal/hash.h>

	#include <linux/unaligned.h>

	#define DRIVER_NAME "stm32-crc32"
	#define CHKSUM_DIGEST_SIZE 4
	#define CHKSUM_BLOCK_SIZE 1

	/* Registers */
	#define CRC_DR 0x00000000
	#define CRC_CR 0x00000008
	#define CRC_INIT 0x00000010
	#define CRC_POL 0x00000014

	/* Registers values */
	#define CRC_CR_RESET BIT(0)
	#define CRC_CR_REV_IN_WORD (BIT(6) \| BIT(5))
	#define CRC_CR_REV_IN_BYTE BIT(5)
	#define CRC_CR_REV_OUT BIT(7)
	#define CRC32C_INIT_DEFAULT 0xFFFFFFFF

	#define CRC_AUTOSUSPEND_DELAY 50

	static unsigned int burst_size;
	module_param(burst_size, uint, 0644);
	MODULE_PARM_DESC(burst_size, "Select burst byte size (0 unlimited)");

	struct stm32_crc {
	struct list_head list;
	struct device *dev;
	void __iomem *regs;
	struct clk *clk;
	spinlock_t lock;
	};

	struct stm32_crc_list {
	struct list_head dev_list;
	spinlock_t lock; /* protect dev_list */
	};

	static struct stm32_crc_list crc_list = {
	.dev_list = LIST_HEAD_INIT(crc_list.dev_list),
	.lock = __SPIN_LOCK_UNLOCKED(crc_list.lock),
	};

	struct stm32_crc_ctx {
	u32 key;
	u32 poly;
	};

	struct stm32_crc_desc_ctx {
	u32 partial; /* crc32c: partial in first 4 bytes of that struct */
	};

	static int stm32_crc32_cra_init(struct crypto_tfm *tfm)
	{
	struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);

	mctx->key = 0;
	mctx->poly = CRC32_POLY_LE;
	return 0;
	}

	static int stm32_crc32c_cra_init(struct crypto_tfm *tfm)
	{
	struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);

	mctx->key = CRC32C_INIT_DEFAULT;
	mctx->poly = CRC32C_POLY_LE;
	return 0;
	}

	static int stm32_crc_setkey(struct crypto_shash tfm, const u8 key,
	unsigned int keylen)
	{
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(tfm);

	if (keylen != sizeof(u32))
	return -EINVAL;

	mctx->key = get_unaligned_le32(key);
	return 0;
	}

	static struct stm32_crc *stm32_crc_get_next_crc(void)
	{
	struct stm32_crc *crc;

	spin_lock_bh(&crc_list.lock);
	crc = list_first_entry_or_null(&crc_list.dev_list, struct stm32_crc, list);
	if (crc)
	list_move_tail(&crc->list, &crc_list.dev_list);
	spin_unlock_bh(&crc_list.lock);

	return crc;
	}

	static int stm32_crc_init(struct shash_desc *desc)
	{
	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
	struct stm32_crc *crc;
	unsigned long flags;

	crc = stm32_crc_get_next_crc();
	if (!crc)
	return -ENODEV;

	pm_runtime_get_sync(crc->dev);

	spin_lock_irqsave(&crc->lock, flags);

	/* Reset, set key, poly and configure in bit reverse mode */
	writel_relaxed(bitrev32(mctx->key), crc->regs + CRC_INIT);
	writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
	writel_relaxed(CRC_CR_RESET \| CRC_CR_REV_IN_WORD \| CRC_CR_REV_OUT,
	crc->regs + CRC_CR);

	/* Store partial result */
	ctx->partial = readl_relaxed(crc->regs + CRC_DR);

	spin_unlock_irqrestore(&crc->lock, flags);

	pm_runtime_mark_last_busy(crc->dev);
	pm_runtime_put_autosuspend(crc->dev);

	return 0;
	}

	static int burst_update(struct shash_desc desc, const u8 d8,
	size_t length)
	{
	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
	struct stm32_crc *crc;

	crc = stm32_crc_get_next_crc();
	if (!crc)
	return -ENODEV;

	pm_runtime_get_sync(crc->dev);

	if (!spin_trylock(&crc->lock)) {
	/* Hardware is busy, calculate crc32 by software */
	if (mctx->poly == CRC32_POLY_LE)
	ctx->partial = crc32_le(ctx->partial, d8, length);
	else
	ctx->partial = __crc32c_le(ctx->partial, d8, length);

	goto pm_out;
	}

	/*
	* Restore previously calculated CRC for this context as init value
	* Restore polynomial configuration
	* Configure in register for word input data,
	* Configure out register in reversed bit mode data.
	*/
	writel_relaxed(bitrev32(ctx->partial), crc->regs + CRC_INIT);
	writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
	writel_relaxed(CRC_CR_RESET \| CRC_CR_REV_IN_WORD \| CRC_CR_REV_OUT,
	crc->regs + CRC_CR);

	if (d8 != PTR_ALIGN(d8, sizeof(u32))) {
	/* Configure for byte data */
	writel_relaxed(CRC_CR_REV_IN_BYTE \| CRC_CR_REV_OUT,
	crc->regs + CRC_CR);
	while (d8 != PTR_ALIGN(d8, sizeof(u32)) && length) {
	writeb_relaxed(*d8++, crc->regs + CRC_DR);
	length--;
	}
	/* Configure for word data */
	writel_relaxed(CRC_CR_REV_IN_WORD \| CRC_CR_REV_OUT,
	crc->regs + CRC_CR);
	}

	for (; length >= sizeof(u32); d8 += sizeof(u32), length -= sizeof(u32))
	writel_relaxed(((u32 )d8), crc->regs + CRC_DR);

	if (length) {
	/* Configure for byte data */
	writel_relaxed(CRC_CR_REV_IN_BYTE \| CRC_CR_REV_OUT,
	crc->regs + CRC_CR);
	while (length--)
	writeb_relaxed(*d8++, crc->regs + CRC_DR);
	}

	/* Store partial result */
	ctx->partial = readl_relaxed(crc->regs + CRC_DR);

	spin_unlock(&crc->lock);

	pm_out:
	pm_runtime_mark_last_busy(crc->dev);
	pm_runtime_put_autosuspend(crc->dev);

	return 0;
	}

	static int stm32_crc_update(struct shash_desc desc, const u8 d8,
	unsigned int length)
	{
	const unsigned int burst_sz = burst_size;
	unsigned int rem_sz;
	const u8 *cur;
	size_t size;
	int ret;

	if (!burst_sz)
	return burst_update(desc, d8, length);

	/* Digest first bytes not 32bit aligned at first pass in the loop */
	size = min_t(size_t, length, burst_sz + (size_t)d8 -
	ALIGN_DOWN((size_t)d8, sizeof(u32)));
	for (rem_sz = length, cur = d8; rem_sz;
	rem_sz -= size, cur += size, size = min(rem_sz, burst_sz)) {
	ret = burst_update(desc, cur, size);
	if (ret)
	return ret;
	}

	return 0;
	}

	static int stm32_crc_final(struct shash_desc desc, u8 out)
	{
	struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
	struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);

	/* Send computed CRC */
	put_unaligned_le32(mctx->poly == CRC32C_POLY_LE ?
	~ctx->partial : ctx->partial, out);

	return 0;
	}

	static int stm32_crc_finup(struct shash_desc desc, const u8 data,
	unsigned int length, u8 *out)
	{
	return stm32_crc_update(desc, data, length) ?:
	stm32_crc_final(desc, out);
	}

	static int stm32_crc_digest(struct shash_desc desc, const u8 data,
	unsigned int length, u8 *out)
	{
	return stm32_crc_init(desc) ?: stm32_crc_finup(desc, data, length, out);
	}

	static unsigned int refcnt;
	static DEFINE_MUTEX(refcnt_lock);
	static struct shash_alg algs[] = {
	/* CRC-32 */
	{
	.setkey = stm32_crc_setkey,
	.init = stm32_crc_init,
	.update = stm32_crc_update,
	.final = stm32_crc_final,
	.finup = stm32_crc_finup,
	.digest = stm32_crc_digest,
	.descsize = sizeof(struct stm32_crc_desc_ctx),
	.digestsize = CHKSUM_DIGEST_SIZE,
	.base = {
	.cra_name = "crc32",
	.cra_driver_name = "stm32-crc32-crc32",
	.cra_priority = 200,
	.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
	.cra_blocksize = CHKSUM_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct stm32_crc_ctx),
	.cra_module = THIS_MODULE,
	.cra_init = stm32_crc32_cra_init,
	}
	},
	/* CRC-32Castagnoli */
	{
	.setkey = stm32_crc_setkey,
	.init = stm32_crc_init,
	.update = stm32_crc_update,
	.final = stm32_crc_final,
	.finup = stm32_crc_finup,
	.digest = stm32_crc_digest,
	.descsize = sizeof(struct stm32_crc_desc_ctx),
	.digestsize = CHKSUM_DIGEST_SIZE,
	.base = {
	.cra_name = "crc32c",
	.cra_driver_name = "stm32-crc32-crc32c",
	.cra_priority = 200,
	.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
	.cra_blocksize = CHKSUM_BLOCK_SIZE,
	.cra_ctxsize = sizeof(struct stm32_crc_ctx),
	.cra_module = THIS_MODULE,
	.cra_init = stm32_crc32c_cra_init,
	}
	}
	};

	static int stm32_crc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct stm32_crc *crc;
	int ret;

	crc = devm_kzalloc(dev, sizeof(*crc), GFP_KERNEL);
	if (!crc)
	return -ENOMEM;

	crc->dev = dev;

	crc->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(crc->regs)) {
	dev_err(dev, "Cannot map CRC IO\n");
	return PTR_ERR(crc->regs);
	}

	crc->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(crc->clk)) {
	dev_err(dev, "Could not get clock\n");
	return PTR_ERR(crc->clk);
	}

	ret = clk_prepare_enable(crc->clk);
	if (ret) {
	dev_err(crc->dev, "Failed to enable clock\n");
	return ret;
	}

	pm_runtime_set_autosuspend_delay(dev, CRC_AUTOSUSPEND_DELAY);
	pm_runtime_use_autosuspend(dev);

	pm_runtime_get_noresume(dev);
	pm_runtime_set_active(dev);
	pm_runtime_irq_safe(dev);
	pm_runtime_enable(dev);

	spin_lock_init(&crc->lock);

	platform_set_drvdata(pdev, crc);

	spin_lock(&crc_list.lock);
	list_add(&crc->list, &crc_list.dev_list);
	spin_unlock(&crc_list.lock);

	mutex_lock(&refcnt_lock);
	if (!refcnt) {
	ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
	if (ret) {
	mutex_unlock(&refcnt_lock);
	dev_err(dev, "Failed to register\n");
	clk_disable_unprepare(crc->clk);
	return ret;
	}
	}
	refcnt++;
	mutex_unlock(&refcnt_lock);

	dev_info(dev, "Initialized\n");

	pm_runtime_put_sync(dev);

	return 0;
	}

	static void stm32_crc_remove(struct platform_device *pdev)
	{
	struct stm32_crc *crc = platform_get_drvdata(pdev);
	int ret = pm_runtime_get_sync(crc->dev);

	spin_lock(&crc_list.lock);
	list_del(&crc->list);
	spin_unlock(&crc_list.lock);

	mutex_lock(&refcnt_lock);
	if (!--refcnt)
	crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
	mutex_unlock(&refcnt_lock);

	pm_runtime_disable(crc->dev);
	pm_runtime_put_noidle(crc->dev);

	if (ret >= 0)
	clk_disable(crc->clk);
	clk_unprepare(crc->clk);
	}

	static int __maybe_unused stm32_crc_suspend(struct device *dev)
	{
	struct stm32_crc *crc = dev_get_drvdata(dev);
	int ret;

	ret = pm_runtime_force_suspend(dev);
	if (ret)
	return ret;

	clk_unprepare(crc->clk);

	return 0;
	}

	static int __maybe_unused stm32_crc_resume(struct device *dev)
	{
	struct stm32_crc *crc = dev_get_drvdata(dev);
	int ret;

	ret = clk_prepare(crc->clk);
	if (ret) {
	dev_err(crc->dev, "Failed to prepare clock\n");
	return ret;
	}

	return pm_runtime_force_resume(dev);
	}

	static int __maybe_unused stm32_crc_runtime_suspend(struct device *dev)
	{
	struct stm32_crc *crc = dev_get_drvdata(dev);

	clk_disable(crc->clk);

	return 0;
	}

	static int __maybe_unused stm32_crc_runtime_resume(struct device *dev)
	{
	struct stm32_crc *crc = dev_get_drvdata(dev);
	int ret;

	ret = clk_enable(crc->clk);
	if (ret) {
	dev_err(crc->dev, "Failed to enable clock\n");
	return ret;
	}

	return 0;
	}

	static const struct dev_pm_ops stm32_crc_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(stm32_crc_suspend,
	stm32_crc_resume)
	SET_RUNTIME_PM_OPS(stm32_crc_runtime_suspend,
	stm32_crc_runtime_resume, NULL)
	};

	static const struct of_device_id stm32_dt_ids[] = {
	{ .compatible = "st,stm32f7-crc", },
	{},
	};
	MODULE_DEVICE_TABLE(of, stm32_dt_ids);

	static struct platform_driver stm32_crc_driver = {
	.probe = stm32_crc_probe,
	.remove = stm32_crc_remove,
	.driver = {
	.name = DRIVER_NAME,
	.pm = &stm32_crc_pm_ops,
	.of_match_table = stm32_dt_ids,
	},
	};

	module_platform_driver(stm32_crc_driver);

	MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
	MODULE_DESCRIPTION("STMicrolectronics STM32 CRC32 hardware driver");
	MODULE_LICENSE("GPL");