// SPDX-License-Identifier: GPL-2.0
/*
 * sun8i-ce-cipher.c - hardware cryptographic offloader for
 * Allwinner H3/A64/H5/H2+/H6/R40 SoC
 *
 * Copyright (C) 2016-2019 Corentin LABBE <clabbe.montjoie@gmail.com>
 *
 * This file add support for AES cipher with 128,192,256 bits keysize in
 * CBC and ECB mode.
 *
 * You could find a link for the datasheet in Documentation/arch/arm/sunxi.rst
 */

#include <linux/bottom_half.h>
#include <linux/crypto.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/pm_runtime.h>
#include <crypto/scatterwalk.h>
#include <crypto/internal/des.h>
#include <crypto/internal/skcipher.h>
#include "sun8i-ce.h"

static int sun8i_ce_cipher_need_fallback(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct scatterlist *sg;
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun8i_ce_alg_template *algt;
        unsigned int todo, len;

        algt = container_of(alg, struct sun8i_ce_alg_template, alg.skcipher.base);

        if (sg_nents_for_len(areq->src, areq->cryptlen) > MAX_SG ||
            sg_nents_for_len(areq->dst, areq->cryptlen) > MAX_SG) {
                if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                        algt->stat_fb_maxsg++;

                return true;
        }

        if (areq->cryptlen < crypto_skcipher_ivsize(tfm)) {
                if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                        algt->stat_fb_leniv++;

                return true;
        }

        if (areq->cryptlen == 0) {
                if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                        algt->stat_fb_len0++;

                return true;
        }

        if (areq->cryptlen % 16) {
                if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                        algt->stat_fb_mod16++;

                return true;
        }

        len = areq->cryptlen;
        sg = areq->src;
        while (sg) {
                if (!IS_ALIGNED(sg->offset, sizeof(u32))) {
                        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                                algt->stat_fb_srcali++;

                        return true;
                }
                todo = min(len, sg->length);
                if (todo % 4) {
                        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                                algt->stat_fb_srclen++;

                        return true;
                }
                len -= todo;
                sg = sg_next(sg);
        }

        len = areq->cryptlen;
        sg = areq->dst;
        while (sg) {
                if (!IS_ALIGNED(sg->offset, sizeof(u32))) {
                        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                                algt->stat_fb_dstali++;

                        return true;
                }
                todo = min(len, sg->length);
                if (todo % 4) {
                        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                                algt->stat_fb_dstlen++;

                        return true;
                }
                len -= todo;
                sg = sg_next(sg);
        }
        return false;
}

static int sun8i_ce_cipher_fallback(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        int err;

        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG)) {
                struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
                struct sun8i_ce_alg_template *algt;

                algt = container_of(alg, struct sun8i_ce_alg_template,
                                    alg.skcipher.base);

                algt->stat_fb++;
        }

        skcipher_request_set_tfm(&rctx->fallback_req, op->fallback_tfm);
        skcipher_request_set_callback(&rctx->fallback_req, areq->base.flags,
                                      areq->base.complete, areq->base.data);
        skcipher_request_set_crypt(&rctx->fallback_req, areq->src, areq->dst,
                                   areq->cryptlen, areq->iv);
        if (rctx->op_dir & CE_DECRYPTION)
                err = crypto_skcipher_decrypt(&rctx->fallback_req);
        else
                err = crypto_skcipher_encrypt(&rctx->fallback_req);
        return err;
}

static int sun8i_ce_cipher_prepare(struct skcipher_request *areq,
                                   struct ce_task *cet)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ce_dev *ce = op->ce;
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun8i_ce_alg_template *algt;
        struct scatterlist *sg;
        unsigned int todo, len, offset, ivsize;
        u32 common, sym;
        int i;
        int nr_sgs = 0;
        int nr_sgd = 0;
        int err = 0;
        int ns = sg_nents_for_len(areq->src, areq->cryptlen);
        int nd = sg_nents_for_len(areq->dst, areq->cryptlen);

        algt = container_of(alg, struct sun8i_ce_alg_template, alg.skcipher.base);

        dev_dbg(ce->dev, "%s %s %u %x IV(%p %u) key=%u\n", __func__,
                crypto_tfm_alg_name(areq->base.tfm),
                areq->cryptlen,
                rctx->op_dir, areq->iv, crypto_skcipher_ivsize(tfm),
                op->keylen);

        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                algt->stat_req++;

        memset(cet, 0, sizeof(struct ce_task));

        cet->t_id = cpu_to_le32(rctx->flow);
        common = ce->variant->alg_cipher[algt->ce_algo_id];
        common |= rctx->op_dir | CE_COMM_INT;
        cet->t_common_ctl = cpu_to_le32(common);
        /* CTS and recent CE (H6) need length in bytes, in word otherwise */
        if (ce->variant->cipher_t_dlen_in_bytes)
                cet->t_dlen = cpu_to_le32(areq->cryptlen);
        else
                cet->t_dlen = cpu_to_le32(areq->cryptlen / 4);

        sym = ce->variant->op_mode[algt->ce_blockmode];
        len = op->keylen;
        switch (len) {
        case 128 / 8:
                sym |= CE_AES_128BITS;
                break;
        case 192 / 8:
                sym |= CE_AES_192BITS;
                break;
        case 256 / 8:
                sym |= CE_AES_256BITS;
                break;
        }

        cet->t_sym_ctl = cpu_to_le32(sym);
        cet->t_asym_ctl = 0;

        rctx->addr_key = dma_map_single(ce->dev, op->key, op->keylen, DMA_TO_DEVICE);
        if (dma_mapping_error(ce->dev, rctx->addr_key)) {
                dev_err(ce->dev, "Cannot DMA MAP KEY\n");
                err = -EFAULT;
                goto theend;
        }
        cet->t_key = desc_addr_val_le32(ce, rctx->addr_key);

        ivsize = crypto_skcipher_ivsize(tfm);
        if (areq->iv && ivsize > 0) {
                if (rctx->op_dir & CE_DECRYPTION) {
                        offset = areq->cryptlen - ivsize;
                        scatterwalk_map_and_copy(rctx->backup_iv, areq->src,
                                                 offset, ivsize, 0);
                }
                memcpy(rctx->bounce_iv, areq->iv, ivsize);
                rctx->addr_iv = dma_map_single(ce->dev, rctx->bounce_iv, ivsize,
                                               DMA_TO_DEVICE);
                if (dma_mapping_error(ce->dev, rctx->addr_iv)) {
                        dev_err(ce->dev, "Cannot DMA MAP IV\n");
                        err = -ENOMEM;
                        goto theend_iv;
                }
                cet->t_iv = desc_addr_val_le32(ce, rctx->addr_iv);
        }

        if (areq->src == areq->dst) {
                nr_sgs = dma_map_sg(ce->dev, areq->src, ns, DMA_BIDIRECTIONAL);
                if (nr_sgs <= 0 || nr_sgs > MAX_SG) {
                        dev_err(ce->dev, "Invalid sg number %d\n", nr_sgs);
                        err = -EINVAL;
                        goto theend_iv;
                }
                nr_sgd = nr_sgs;
        } else {
                nr_sgs = dma_map_sg(ce->dev, areq->src, ns, DMA_TO_DEVICE);
                if (nr_sgs <= 0 || nr_sgs > MAX_SG) {
                        dev_err(ce->dev, "Invalid sg number %d\n", nr_sgs);
                        err = -EINVAL;
                        goto theend_iv;
                }
                nr_sgd = dma_map_sg(ce->dev, areq->dst, nd, DMA_FROM_DEVICE);
                if (nr_sgd <= 0 || nr_sgd > MAX_SG) {
                        dev_err(ce->dev, "Invalid sg number %d\n", nr_sgd);
                        err = -EINVAL;
                        goto theend_sgs;
                }
        }

        len = areq->cryptlen;
        for_each_sg(areq->src, sg, nr_sgs, i) {
                cet->t_src[i].addr = desc_addr_val_le32(ce, sg_dma_address(sg));
                todo = min(len, sg_dma_len(sg));
                cet->t_src[i].len = cpu_to_le32(todo / 4);
                dev_dbg(ce->dev, "%s total=%u SG(%d %u off=%d) todo=%u\n", __func__,
                        areq->cryptlen, i, cet->t_src[i].len, sg->offset, todo);
                len -= todo;
        }
        if (len > 0) {
                dev_err(ce->dev, "remaining len %d\n", len);
                err = -EINVAL;
                goto theend_sgs;
        }

        len = areq->cryptlen;
        for_each_sg(areq->dst, sg, nr_sgd, i) {
                cet->t_dst[i].addr = desc_addr_val_le32(ce, sg_dma_address(sg));
                todo = min(len, sg_dma_len(sg));
                cet->t_dst[i].len = cpu_to_le32(todo / 4);
                dev_dbg(ce->dev, "%s total=%u SG(%d %u off=%d) todo=%u\n", __func__,
                        areq->cryptlen, i, cet->t_dst[i].len, sg->offset, todo);
                len -= todo;
        }
        if (len > 0) {
                dev_err(ce->dev, "remaining len %d\n", len);
                err = -EINVAL;
                goto theend_sgs;
        }

        rctx->nr_sgs = ns;
        rctx->nr_sgd = nd;
        return 0;

theend_sgs:
        if (areq->src == areq->dst) {
                dma_unmap_sg(ce->dev, areq->src, ns, DMA_BIDIRECTIONAL);
        } else {
                if (nr_sgs > 0)
                        dma_unmap_sg(ce->dev, areq->src, ns, DMA_TO_DEVICE);

                if (nr_sgd > 0)
                        dma_unmap_sg(ce->dev, areq->dst, nd, DMA_FROM_DEVICE);
        }

theend_iv:
        if (areq->iv && ivsize > 0) {
                if (!dma_mapping_error(ce->dev, rctx->addr_iv))
                        dma_unmap_single(ce->dev, rctx->addr_iv, ivsize,
                                         DMA_TO_DEVICE);

                offset = areq->cryptlen - ivsize;
                if (rctx->op_dir & CE_DECRYPTION) {
                        memcpy(areq->iv, rctx->backup_iv, ivsize);
                        memzero_explicit(rctx->backup_iv, ivsize);
                } else {
                        scatterwalk_map_and_copy(areq->iv, areq->dst, offset,
                                                 ivsize, 0);
                }
                memzero_explicit(rctx->bounce_iv, ivsize);
        }

        dma_unmap_single(ce->dev, rctx->addr_key, op->keylen, DMA_TO_DEVICE);

theend:
        return err;
}

static void sun8i_ce_cipher_unprepare(struct skcipher_request *areq,
                                      struct ce_task *cet)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ce_dev *ce = op->ce;
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        unsigned int ivsize, offset;
        int nr_sgs = rctx->nr_sgs;
        int nr_sgd = rctx->nr_sgd;

        ivsize = crypto_skcipher_ivsize(tfm);

        if (areq->src == areq->dst) {
                dma_unmap_sg(ce->dev, areq->src, nr_sgs, DMA_BIDIRECTIONAL);
        } else {
                if (nr_sgs > 0)
                        dma_unmap_sg(ce->dev, areq->src, nr_sgs, DMA_TO_DEVICE);
                dma_unmap_sg(ce->dev, areq->dst, nr_sgd, DMA_FROM_DEVICE);
        }

        if (areq->iv && ivsize > 0) {
                if (cet->t_iv)
                        dma_unmap_single(ce->dev, rctx->addr_iv, ivsize,
                                         DMA_TO_DEVICE);
                offset = areq->cryptlen - ivsize;
                if (rctx->op_dir & CE_DECRYPTION) {
                        memcpy(areq->iv, rctx->backup_iv, ivsize);
                        memzero_explicit(rctx->backup_iv, ivsize);
                } else {
                        scatterwalk_map_and_copy(areq->iv, areq->dst, offset,
                                                 ivsize, 0);
                }
                memzero_explicit(rctx->bounce_iv, ivsize);
        }

        dma_unmap_single(ce->dev, rctx->addr_key, op->keylen, DMA_TO_DEVICE);
}

int sun8i_ce_cipher_do_one(struct crypto_engine *engine, void *areq)
{
        struct skcipher_request *req = skcipher_request_cast(areq);
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(req);
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        struct sun8i_cipher_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
        struct sun8i_ce_dev *ce = ctx->ce;
        struct sun8i_ce_flow *chan;
        int err;

        chan = &ce->chanlist[rctx->flow];

        err = sun8i_ce_cipher_prepare(req, chan->tl);
        if (err)
                return err;

        err = sun8i_ce_run_task(ce, rctx->flow,
                                crypto_tfm_alg_name(req->base.tfm));

        sun8i_ce_cipher_unprepare(req, chan->tl);

        local_bh_disable();
        crypto_finalize_skcipher_request(engine, req, err);
        local_bh_enable();

        return 0;
}

int sun8i_ce_skdecrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        struct crypto_engine *engine;
        int e;

        rctx->op_dir = CE_DECRYPTION;
        if (sun8i_ce_cipher_need_fallback(areq))
                return sun8i_ce_cipher_fallback(areq);

        e = sun8i_ce_get_engine_number(op->ce);
        rctx->flow = e;
        engine = op->ce->chanlist[e].engine;

        return crypto_transfer_skcipher_request_to_engine(engine, areq);
}

int sun8i_ce_skencrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        struct crypto_engine *engine;
        int e;

        rctx->op_dir = CE_ENCRYPTION;
        if (sun8i_ce_cipher_need_fallback(areq))
                return sun8i_ce_cipher_fallback(areq);

        e = sun8i_ce_get_engine_number(op->ce);
        rctx->flow = e;
        engine = op->ce->chanlist[e].engine;

        return crypto_transfer_skcipher_request_to_engine(engine, areq);
}

int sun8i_ce_cipher_init(struct crypto_tfm *tfm)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_tfm_ctx(tfm);
        struct sun8i_ce_alg_template *algt;
        const char *name = crypto_tfm_alg_name(tfm);
        struct crypto_skcipher *sktfm = __crypto_skcipher_cast(tfm);
        struct skcipher_alg *alg = crypto_skcipher_alg(sktfm);
        int err;

        memset(op, 0, sizeof(struct sun8i_cipher_tfm_ctx));

        algt = container_of(alg, struct sun8i_ce_alg_template, alg.skcipher.base);
        op->ce = algt->ce;

        op->fallback_tfm = crypto_alloc_skcipher(name, 0, CRYPTO_ALG_NEED_FALLBACK);
        if (IS_ERR(op->fallback_tfm)) {
                dev_err(op->ce->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(sktfm, sizeof(struct sun8i_cipher_req_ctx) +
                                    crypto_skcipher_reqsize(op->fallback_tfm));

        if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG))
                memcpy(algt->fbname,
                       crypto_skcipher_driver_name(op->fallback_tfm),
                       CRYPTO_MAX_ALG_NAME);

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

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

void sun8i_ce_cipher_exit(struct crypto_tfm *tfm)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_tfm_ctx(tfm);

        kfree_sensitive(op->key);
        crypto_free_skcipher(op->fallback_tfm);
        pm_runtime_put_sync_suspend(op->ce->dev);
}

int sun8i_ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ce_dev *ce = op->ce;

        switch (keylen) {
        case 128 / 8:
                break;
        case 192 / 8:
                break;
        case 256 / 8:
                break;
        default:
                dev_dbg(ce->dev, "ERROR: Invalid keylen %u\n", keylen);
                return -EINVAL;
        }
        kfree_sensitive(op->key);
        op->keylen = keylen;
        op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
        if (!op->key)
                return -ENOMEM;

        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);
}

int sun8i_ce_des3_setkey(struct crypto_skcipher *tfm, const u8 *key,
                         unsigned int keylen)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        int err;

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

        kfree_sensitive(op->key);
        op->keylen = keylen;
        op->key = kmemdup(key, keylen, GFP_KERNEL | GFP_DMA);
        if (!op->key)
                return -ENOMEM;

        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);
}