// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * sun4i-ss-cipher.c - hardware cryptographic accelerator for Allwinner A20 SoC
 *
 * Copyright (C) 2013-2015 Corentin LABBE <clabbe.montjoie@gmail.com>
 *
 * This file add support for AES cipher with 128,192,256 bits
 * keysize in CBC and ECB mode.
 * Add support also for DES and 3DES in CBC and ECB mode.
 *
 * You could find the datasheet in Documentation/arch/arm/sunxi.rst
 */
#include "sun4i-ss.h"

static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;
        unsigned int ivsize = crypto_skcipher_ivsize(tfm);
        struct sun4i_cipher_req_ctx *ctx = skcipher_request_ctx(areq);
        u32 mode = ctx->mode;
        /* when activating SS, the default FIFO space is SS_RX_DEFAULT(32) */
        u32 rx_cnt = SS_RX_DEFAULT;
        u32 tx_cnt = 0;
        u32 spaces;
        u32 v;
        int err = 0;
        unsigned int i;
        unsigned int ileft = areq->cryptlen;
        unsigned int oleft = areq->cryptlen;
        unsigned int todo;
        unsigned long pi = 0, po = 0; /* progress for in and out */
        bool miter_err;
        struct sg_mapping_iter mi, mo;
        unsigned int oi, oo; /* offset for in and out */
        unsigned long flags;
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun4i_ss_alg_template *algt;

        if (!areq->cryptlen)
                return 0;

        if (!areq->src || !areq->dst) {
                dev_err_ratelimited(ss->dev, "ERROR: Some SGs are NULL\n");
                return -EINVAL;
        }

        if (areq->iv && ivsize > 0 && mode & SS_DECRYPTION) {
                scatterwalk_map_and_copy(ctx->backup_iv, areq->src,
                                         areq->cryptlen - ivsize, ivsize, 0);
        }

        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN4I_SS_DEBUG)) {
                algt = container_of(alg, struct sun4i_ss_alg_template, alg.crypto);
                algt->stat_opti++;
                algt->stat_bytes += areq->cryptlen;
        }

        spin_lock_irqsave(&ss->slock, flags);

        for (i = 0; i < op->keylen / 4; i++)
                writesl(ss->base + SS_KEY0 + i * 4, &op->key[i], 1);

        if (areq->iv) {
                for (i = 0; i < 4 && i < ivsize / 4; i++) {
                        v = *(u32 *)(areq->iv + i * 4);
                        writesl(ss->base + SS_IV0 + i * 4, &v, 1);
                }
        }
        writel(mode, ss->base + SS_CTL);


        ileft = areq->cryptlen / 4;
        oleft = areq->cryptlen / 4;
        oi = 0;
        oo = 0;
        do {
                if (ileft) {
                        sg_miter_start(&mi, areq->src, sg_nents(areq->src),
                                        SG_MITER_FROM_SG | SG_MITER_ATOMIC);
                        if (pi)
                                sg_miter_skip(&mi, pi);
                        miter_err = sg_miter_next(&mi);
                        if (!miter_err || !mi.addr) {
                                dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
                                err = -EINVAL;
                                goto release_ss;
                        }
                        todo = min(rx_cnt, ileft);
                        todo = min_t(size_t, todo, (mi.length - oi) / 4);
                        if (todo) {
                                ileft -= todo;
                                writesl(ss->base + SS_RXFIFO, mi.addr + oi, todo);
                                oi += todo * 4;
                        }
                        if (oi == mi.length) {
                                pi += mi.length;
                                oi = 0;
                        }
                        sg_miter_stop(&mi);
                }

                spaces = readl(ss->base + SS_FCSR);
                rx_cnt = SS_RXFIFO_SPACES(spaces);
                tx_cnt = SS_TXFIFO_SPACES(spaces);

                sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
                               SG_MITER_TO_SG | SG_MITER_ATOMIC);
                if (po)
                        sg_miter_skip(&mo, po);
                miter_err = sg_miter_next(&mo);
                if (!miter_err || !mo.addr) {
                        dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
                        err = -EINVAL;
                        goto release_ss;
                }
                todo = min(tx_cnt, oleft);
                todo = min_t(size_t, todo, (mo.length - oo) / 4);
                if (todo) {
                        oleft -= todo;
                        readsl(ss->base + SS_TXFIFO, mo.addr + oo, todo);
                        oo += todo * 4;
                }
                if (oo == mo.length) {
                        oo = 0;
                        po += mo.length;
                }
                sg_miter_stop(&mo);
        } while (oleft);

        if (areq->iv) {
                if (mode & SS_DECRYPTION) {
                        memcpy(areq->iv, ctx->backup_iv, ivsize);
                        memzero_explicit(ctx->backup_iv, ivsize);
                } else {
                        scatterwalk_map_and_copy(areq->iv, areq->dst, areq->cryptlen - ivsize,
                                                 ivsize, 0);
                }
        }

release_ss:
        writel(0, ss->base + SS_CTL);
        spin_unlock_irqrestore(&ss->slock, flags);
        return err;
}

static int noinline_for_stack sun4i_ss_cipher_poll_fallback(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *ctx = skcipher_request_ctx(areq);
        int err;
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun4i_ss_alg_template *algt;

        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN4I_SS_DEBUG)) {
                algt = container_of(alg, struct sun4i_ss_alg_template, alg.crypto);
                algt->stat_fb++;
        }

        skcipher_request_set_tfm(&ctx->fallback_req, op->fallback_tfm);
        skcipher_request_set_callback(&ctx->fallback_req, areq->base.flags,
                                      areq->base.complete, areq->base.data);
        skcipher_request_set_crypt(&ctx->fallback_req, areq->src, areq->dst,
                                   areq->cryptlen, areq->iv);
        if (ctx->mode & SS_DECRYPTION)
                err = crypto_skcipher_decrypt(&ctx->fallback_req);
        else
                err = crypto_skcipher_encrypt(&ctx->fallback_req);

        return err;
}

/* Generic function that support SG with size not multiple of 4 */
static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;
        int no_chunk = 1;
        struct scatterlist *in_sg = areq->src;
        struct scatterlist *out_sg = areq->dst;
        unsigned int ivsize = crypto_skcipher_ivsize(tfm);
        struct sun4i_cipher_req_ctx *ctx = skcipher_request_ctx(areq);
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun4i_ss_alg_template *algt;
        u32 mode = ctx->mode;
        /* when activating SS, the default FIFO space is SS_RX_DEFAULT(32) */
        u32 rx_cnt = SS_RX_DEFAULT;
        u32 tx_cnt = 0;
        u32 v;
        u32 spaces;
        int err = 0;
        unsigned int i;
        unsigned int ileft = areq->cryptlen;
        unsigned int oleft = areq->cryptlen;
        unsigned int todo;
        struct sg_mapping_iter mi, mo;
        unsigned long pi = 0, po = 0; /* progress for in and out */
        bool miter_err;
        unsigned int oi, oo;    /* offset for in and out */
        unsigned int ob = 0;    /* offset in buf */
        unsigned int obo = 0;   /* offset in bufo*/
        unsigned int obl = 0;   /* length of data in bufo */
        unsigned long flags;
        bool need_fallback = false;

        if (!areq->cryptlen)
                return 0;

        if (!areq->src || !areq->dst) {
                dev_err_ratelimited(ss->dev, "ERROR: Some SGs are NULL\n");
                return -EINVAL;
        }

        algt = container_of(alg, struct sun4i_ss_alg_template, alg.crypto);
        if (areq->cryptlen % algt->alg.crypto.base.cra_blocksize)
                need_fallback = true;

        /*
         * if we have only SGs with size multiple of 4,
         * we can use the SS optimized function
         */
        while (in_sg && no_chunk == 1) {
                if ((in_sg->length | in_sg->offset) & 3u)
                        no_chunk = 0;
                in_sg = sg_next(in_sg);
        }
        while (out_sg && no_chunk == 1) {
                if ((out_sg->length | out_sg->offset) & 3u)
                        no_chunk = 0;
                out_sg = sg_next(out_sg);
        }

        if (no_chunk == 1 && !need_fallback)
                return sun4i_ss_opti_poll(areq);

        if (need_fallback)
                return sun4i_ss_cipher_poll_fallback(areq);

        if (areq->iv && ivsize > 0 && mode & SS_DECRYPTION) {
                scatterwalk_map_and_copy(ctx->backup_iv, areq->src,
                                         areq->cryptlen - ivsize, ivsize, 0);
        }

        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN4I_SS_DEBUG)) {
                algt->stat_req++;
                algt->stat_bytes += areq->cryptlen;
        }

        spin_lock_irqsave(&ss->slock, flags);

        for (i = 0; i < op->keylen / 4; i++)
                writesl(ss->base + SS_KEY0 + i * 4, &op->key[i], 1);

        if (areq->iv) {
                for (i = 0; i < 4 && i < ivsize / 4; i++) {
                        v = *(u32 *)(areq->iv + i * 4);
                        writesl(ss->base + SS_IV0 + i * 4, &v, 1);
                }
        }
        writel(mode, ss->base + SS_CTL);

        ileft = areq->cryptlen;
        oleft = areq->cryptlen;
        oi = 0;
        oo = 0;

        while (oleft) {
                if (ileft) {
                        sg_miter_start(&mi, areq->src, sg_nents(areq->src),
                                       SG_MITER_FROM_SG | SG_MITER_ATOMIC);
                        if (pi)
                                sg_miter_skip(&mi, pi);
                        miter_err = sg_miter_next(&mi);
                        if (!miter_err || !mi.addr) {
                                dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
                                err = -EINVAL;
                                goto release_ss;
                        }
                        /*
                         * todo is the number of consecutive 4byte word that we
                         * can read from current SG
                         */
                        todo = min(rx_cnt, ileft / 4);
                        todo = min_t(size_t, todo, (mi.length - oi) / 4);
                        if (todo && !ob) {
                                writesl(ss->base + SS_RXFIFO, mi.addr + oi,
                                        todo);
                                ileft -= todo * 4;
                                oi += todo * 4;
                        } else {
                                /*
                                 * not enough consecutive bytes, so we need to
                                 * linearize in buf. todo is in bytes
                                 * After that copy, if we have a multiple of 4
                                 * we need to be able to write all buf in one
                                 * pass, so it is why we min() with rx_cnt
                                 */
                                todo = min(rx_cnt * 4 - ob, ileft);
                                todo = min_t(size_t, todo, mi.length - oi);
                                memcpy(ss->buf + ob, mi.addr + oi, todo);
                                ileft -= todo;
                                oi += todo;
                                ob += todo;
                                if (!(ob % 4)) {
                                        writesl(ss->base + SS_RXFIFO, ss->buf,
                                                ob / 4);
                                        ob = 0;
                                }
                        }
                        if (oi == mi.length) {
                                pi += mi.length;
                                oi = 0;
                        }
                        sg_miter_stop(&mi);
                }

                spaces = readl(ss->base + SS_FCSR);
                rx_cnt = SS_RXFIFO_SPACES(spaces);
                tx_cnt = SS_TXFIFO_SPACES(spaces);

                if (!tx_cnt)
                        continue;
                sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
                               SG_MITER_TO_SG | SG_MITER_ATOMIC);
                if (po)
                        sg_miter_skip(&mo, po);
                miter_err = sg_miter_next(&mo);
                if (!miter_err || !mo.addr) {
                        dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
                        err = -EINVAL;
                        goto release_ss;
                }
                /* todo in 4bytes word */
                todo = min(tx_cnt, oleft / 4);
                todo = min_t(size_t, todo, (mo.length - oo) / 4);

                if (todo) {
                        readsl(ss->base + SS_TXFIFO, mo.addr + oo, todo);
                        oleft -= todo * 4;
                        oo += todo * 4;
                        if (oo == mo.length) {
                                po += mo.length;
                                oo = 0;
                        }
                } else {
                        /*
                         * read obl bytes in bufo, we read at maximum for
                         * emptying the device
                         */
                        readsl(ss->base + SS_TXFIFO, ss->bufo, tx_cnt);
                        obl = tx_cnt * 4;
                        obo = 0;
                        do {
                                /*
                                 * how many bytes we can copy ?
                                 * no more than remaining SG size
                                 * no more than remaining buffer
                                 * no need to test against oleft
                                 */
                                todo = min_t(size_t,
                                             mo.length - oo, obl - obo);
                                memcpy(mo.addr + oo, ss->bufo + obo, todo);
                                oleft -= todo;
                                obo += todo;
                                oo += todo;
                                if (oo == mo.length) {
                                        po += mo.length;
                                        sg_miter_next(&mo);
                                        oo = 0;
                                }
                        } while (obo < obl);
                        /* bufo must be fully used here */
                }
                sg_miter_stop(&mo);
        }
        if (areq->iv) {
                if (mode & SS_DECRYPTION) {
                        memcpy(areq->iv, ctx->backup_iv, ivsize);
                        memzero_explicit(ctx->backup_iv, ivsize);
                } else {
                        scatterwalk_map_and_copy(areq->iv, areq->dst, areq->cryptlen - ivsize,
                                                 ivsize, 0);
                }
        }

release_ss:
        writel(0, ss->base + SS_CTL);
        spin_unlock_irqrestore(&ss->slock, flags);

        return err;
}

/* CBC AES */
int sun4i_ss_cbc_aes_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_CBC | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cbc_aes_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_CBC | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* ECB AES */
int sun4i_ss_ecb_aes_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_ECB | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_ecb_aes_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_ECB | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* CBC DES */
int sun4i_ss_cbc_des_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_CBC | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cbc_des_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_CBC | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* ECB DES */
int sun4i_ss_ecb_des_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_ECB | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_ecb_des_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_ECB | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* CBC 3DES */
int sun4i_ss_cbc_des3_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_CBC | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cbc_des3_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_CBC | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* ECB 3DES */
int sun4i_ss_ecb_des3_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_ECB | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_ecb_des3_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_ECB | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cipher_init(struct crypto_tfm *tfm)
{
        struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
        struct sun4i_ss_alg_template *algt;
        const char *name = crypto_tfm_alg_name(tfm);
        int err;

        memset(op, 0, sizeof(struct sun4i_tfm_ctx));

        algt = container_of(tfm->__crt_alg, struct sun4i_ss_alg_template,
                            alg.crypto.base);
        op->ss = algt->ss;

        op->fallback_tfm = crypto_alloc_skcipher(name, 0, CRYPTO_ALG_NEED_FALLBACK);
        if (IS_ERR(op->fallback_tfm)) {
                dev_err(op->ss->dev, "ERROR: Cannot allocate fallback for %s %ld\n",
                        name, PTR_ERR(op->fallback_tfm));
                return PTR_ERR(op->fallback_tfm);
        }

        crypto_skcipher_set_reqsize(__crypto_skcipher_cast(tfm),
                                    sizeof(struct sun4i_cipher_req_ctx) +
                                    crypto_skcipher_reqsize(op->fallback_tfm));

        err = pm_runtime_resume_and_get(op->ss->dev);
        if (err < 0)
                goto error_pm;

        return 0;
error_pm:
        crypto_free_skcipher(op->fallback_tfm);
        return err;
}

void sun4i_ss_cipher_exit(struct crypto_tfm *tfm)
{
        struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);

        crypto_free_skcipher(op->fallback_tfm);
        pm_runtime_put(op->ss->dev);
}

/* check and set the AES key, prepare the mode to be used */
int sun4i_ss_aes_setkey(struct crypto_skcipher *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;

        switch (keylen) {
        case 128 / 8:
                op->keymode = SS_AES_128BITS;
                break;
        case 192 / 8:
                op->keymode = SS_AES_192BITS;
                break;
        case 256 / 8:
                op->keymode = SS_AES_256BITS;
                break;
        default:
                dev_dbg(ss->dev, "ERROR: Invalid keylen %u\n", keylen);
                return -EINVAL;
        }
        op->keylen = keylen;
        memcpy(op->key, key, keylen);

        crypto_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK);
        crypto_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);

        return crypto_skcipher_setkey(op->fallback_tfm, key, keylen);
}

/* check and set the DES key, prepare the mode to be used */
int sun4i_ss_des_setkey(struct crypto_skcipher *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        int err;

        err = verify_skcipher_des_key(tfm, key);
        if (err)
                return err;

        op->keylen = keylen;
        memcpy(op->key, key, keylen);

        crypto_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK);
        crypto_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);

        return crypto_skcipher_setkey(op->fallback_tfm, key, keylen);
}

/* check and set the 3DES key, prepare the mode to be used */
int sun4i_ss_des3_setkey(struct crypto_skcipher *tfm, const u8 *key,
                         unsigned int keylen)
{
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        int err;

        err = verify_skcipher_des3_key(tfm, key);
        if (err)
                return err;

        op->keylen = keylen;
        memcpy(op->key, key, keylen);

        crypto_skcipher_clear_flags(op->fallback_tfm, CRYPTO_TFM_REQ_MASK);
        crypto_skcipher_set_flags(op->fallback_tfm, tfm->base.crt_flags & CRYPTO_TFM_REQ_MASK);

        return crypto_skcipher_setkey(op->fallback_tfm, key, keylen);
}