path: root/drivers/crypto/atmel-tdes.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Cryptographic API.
 *
 * Support for ATMEL DES/TDES HW acceleration.
 *
 * Copyright (c) 2012 Eukréa Electromatique - ATMEL
 * Author: Nicolas Royer <nicolas@eukrea.com>
 *
 * Some ideas are from omap-aes.c drivers.
 */


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/hw_random.h>
#include <linux/platform_device.h>

#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/mod_devicetable.h>
#include <linux/delay.h>
#include <linux/crypto.h>
#include <crypto/scatterwalk.h>
#include <crypto/algapi.h>
#include <crypto/internal/des.h>
#include <crypto/internal/skcipher.h>
#include "atmel-tdes-regs.h"

#define ATMEL_TDES_PRIORITY	300

/* TDES flags  */
/* Reserve bits [17:16], [13:12], [2:0] for AES Mode Register */
#define TDES_FLAGS_ENCRYPT	TDES_MR_CYPHER_ENC
#define TDES_FLAGS_OPMODE_MASK	(TDES_MR_OPMOD_MASK | TDES_MR_CFBS_MASK)
#define TDES_FLAGS_ECB		TDES_MR_OPMOD_ECB
#define TDES_FLAGS_CBC		TDES_MR_OPMOD_CBC

#define TDES_FLAGS_MODE_MASK	(TDES_FLAGS_OPMODE_MASK | TDES_FLAGS_ENCRYPT)

#define TDES_FLAGS_INIT		BIT(3)
#define TDES_FLAGS_FAST		BIT(4)
#define TDES_FLAGS_BUSY		BIT(5)
#define TDES_FLAGS_DMA		BIT(6)

#define ATMEL_TDES_QUEUE_LENGTH	50

struct atmel_tdes_caps {
	bool	has_dma;
};

struct atmel_tdes_dev;

struct atmel_tdes_ctx {
	struct atmel_tdes_dev *dd;

	int		keylen;
	u32		key[DES3_EDE_KEY_SIZE / sizeof(u32)];
	unsigned long	flags;

	u16		block_size;
};

struct atmel_tdes_reqctx {
	unsigned long mode;
	u8 lastc[DES_BLOCK_SIZE];
};

struct atmel_tdes_dma {
	struct dma_chan			*chan;
	struct dma_slave_config dma_conf;
};

struct atmel_tdes_dev {
	struct list_head	list;
	unsigned long		phys_base;
	void __iomem		*io_base;

	struct atmel_tdes_ctx	*ctx;
	struct device		*dev;
	struct clk			*iclk;
	int					irq;

	unsigned long		flags;

	spinlock_t		lock;
	struct crypto_queue	queue;

	struct tasklet_struct	done_task;
	struct tasklet_struct	queue_task;

	struct skcipher_request	*req;
	size_t				total;

	struct scatterlist	*in_sg;
	unsigned int		nb_in_sg;
	size_t				in_offset;
	struct scatterlist	*out_sg;
	unsigned int		nb_out_sg;
	size_t				out_offset;

	size_t	buflen;
	size_t	dma_size;

	void	*buf_in;
	int		dma_in;
	dma_addr_t	dma_addr_in;
	struct atmel_tdes_dma	dma_lch_in;

	void	*buf_out;
	int		dma_out;
	dma_addr_t	dma_addr_out;
	struct atmel_tdes_dma	dma_lch_out;

	struct atmel_tdes_caps	caps;

	u32	hw_version;
};

struct atmel_tdes_drv {
	struct list_head	dev_list;
	spinlock_t		lock;
};

static struct atmel_tdes_drv atmel_tdes = {
	.dev_list = LIST_HEAD_INIT(atmel_tdes.dev_list),
	.lock = __SPIN_LOCK_UNLOCKED(atmel_tdes.lock),
};

static int atmel_tdes_sg_copy(struct scatterlist **sg, size_t *offset,
			void *buf, size_t buflen, size_t total, int out)
{
	size_t count, off = 0;

	while (buflen && total) {
		count = min((*sg)->length - *offset, total);
		count = min(count, buflen);

		if (!count)
			return off;

		scatterwalk_map_and_copy(buf + off, *sg, *offset, count, out);

		off += count;
		buflen -= count;
		*offset += count;
		total -= count;

		if (*offset == (*sg)->length) {
			*sg = sg_next(*sg);
			if (*sg)
				*offset = 0;
			else
				total = 0;
		}
	}

	return off;
}

static inline u32 atmel_tdes_read(struct atmel_tdes_dev *dd, u32 offset)
{
	return readl_relaxed(dd->io_base + offset);
}

static inline void atmel_tdes_write(struct atmel_tdes_dev *dd,
					u32 offset, u32 value)
{
	writel_relaxed(value, dd->io_base + offset);
}

static void atmel_tdes_write_n(struct atmel_tdes_dev *dd, u32 offset,
			       const u32 *value, int count)
{
	for (; count--; value++, offset += 4)
		atmel_tdes_write(dd, offset, *value);
}

static struct atmel_tdes_dev *atmel_tdes_dev_alloc(void)
{
	struct atmel_tdes_dev *tdes_dd;

	spin_lock_bh(&atmel_tdes.lock);
	/* One TDES IP per SoC. */
	tdes_dd = list_first_entry_or_null(&atmel_tdes.dev_list,
					   struct atmel_tdes_dev, list);
	spin_unlock_bh(&atmel_tdes.lock);
	return tdes_dd;
}

static int atmel_tdes_hw_init(struct atmel_tdes_dev *dd)
{
	int err;

	err = clk_prepare_enable(dd->iclk);
	if (err