path: root/drivers/crypto/mv_cesa.c

/*
 * Support for Marvell's crypto engine which can be found on some Orion5X
 * boards.
 *
 * Author: Sebastian Andrzej Siewior < sebastian at breakpoint dot cc >
 * License: GPLv2
 *
 */
#include <crypto/aes.h>
#include <crypto/algapi.h>
#include <linux/crypto.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kthread.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <crypto/internal/hash.h>
#include <crypto/sha.h>

#include "mv_cesa.h"

#define MV_CESA	"MV-CESA:"
#define MAX_HW_HASH_SIZE	0xFFFF

/*
 * STM:
 *   /---------------------------------------\
 *   |					     | request complete
 *  \./					     |
 * IDLE -> new request -> BUSY -> done -> DEQUEUE
 *                         /°\               |
 *			    |		     | more scatter entries
 *			    \________________/
 */
enum engine_status {
	ENGINE_IDLE,
	ENGINE_BUSY,
	ENGINE_W_DEQUEUE,
};

/**
 * struct req_progress - used for every crypt request
 * @src_sg_it:		sg iterator for src
 * @dst_sg_it:		sg iterator for dst
 * @sg_src_left:	bytes left in src to process (scatter list)
 * @src_start:		offset to add to src start position (scatter list)
 * @crypt_len:		length of current hw crypt/hash process
 * @hw_nbytes:		total bytes to process in hw for this request
 * @copy_back:		whether to copy data back (crypt) or not (hash)
 * @sg_dst_left:	bytes left dst to process in this scatter list
 * @dst_start:		offset to add to dst start position (scatter list)
 * @hw_processed_bytes:	number of bytes processed by hw (request).
 *
 * sg helper are used to iterate over the scatterlist. Since the size of the
 * SRAM may be less than the scatter size, this struct struct is used to keep
 * track of progress within current scatterlist.
 */
struct req_progress {
	struct sg_mapping_iter src_sg_it;
	struct sg_mapping_iter dst_sg_it;
	void (*complete) (void);
	void (*process) (int is_first);

	/* src mostly */
	int sg_src_left;
	int src_start;
	int crypt_len;
	int hw_nbytes;
	/* dst mostly */
	int copy_back;
	int sg_dst_left;
	int dst_start;
	int hw_processed_bytes;
};

struct crypto_priv {
	void __iomem *reg;
	void __iomem *sram;
	int irq;
	struct task_struct *queue_th;

	/* the lock protects queue and eng_st */
	spinlock_t lock;
	struct crypto_queue queue;
	enum engine_status eng_st;
	struct crypto_async_request *cur_req;
	struct req_progress p;
	int max_req_size;
	int sram_size;
	int has_sha1;
	int has_hmac_sha1;
};

static struct crypto_priv *cpg;

struct mv_ctx {
	u8 aes_enc_key[AES_KEY_LEN];
	u32 aes_dec_key[8];
	int key_len;
	u32 need_calc_aes_dkey;
};

enum crypto_op {
	COP_AES_ECB,
	COP_AES_CBC,
};

struct mv_req_ctx {
	enum crypto_op op;
	int decrypt;
};

enum hash_op {
	COP_SHA1,
	COP_HMAC_SHA1
};

struct mv_tfm_hash_ctx {
	struct crypto_shash *fallback;
	struct crypto_shash *base_hash;
	u32 ivs[2 * SHA1_DIGEST_SIZE / 4];
	int count_add;
	enum hash_op op;
};

struct mv_req_hash_ctx {
	u64 count;
	u32 state[SHA1_DIGEST_SIZE / 4];
	u8 buffer[SHA1_BLOCK_SIZE];
	int first_hash;		/* marks that we don't have previous state */
	int last_chunk;		/* marks that this is the 'final' request */
	int extra_bytes;	/* unprocessed bytes in buffer */
	enum hash_op op;
	int count_add;
	struct scatterlist dummysg;
};

static void compute_aes_dec_key(struct mv_ctx *ctx)
{
	struct crypto_aes_ctx gen_aes_key;
	int key_pos;

	if (!ctx->need_calc_aes_dkey)
		return;

	crypto_aes_expand_key(&gen_aes_key, ctx->aes_enc_key, ctx->key_len);

	key_pos = ctx->key_len + 24;
	memcpy(ctx->aes_dec_key, &gen_aes_key.key_enc[key_pos], 4 * 4);
	switch (ctx->key_len) {
	case AES_KEYSIZE_256:
		key_pos -= 2;
		/* fall */
	case AES_KEYSIZE_192:
		key_pos -= 2;