// SPDX-License-Identifier: GPL-2.0
/*
 * sun8i-ss-cipher.c - hardware cryptographic offloader for
 * Allwinner A80/A83T 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/skcipher.h>
#include "sun8i-ss.h"

static bool sun8i_ss_need_fallback(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun8i_ss_alg_template *algt = container_of(alg, struct sun8i_ss_alg_template, alg.skcipher.base);
        struct scatterlist *in_sg = areq->src;
        struct scatterlist *out_sg = areq->dst;
        struct scatterlist *sg;
        unsigned int todo, len;

        if (areq->cryptlen == 0 || areq->cryptlen % 16) {
                algt->stat_fb_len++;
                return true;
        }

        if (sg_nents_for_len(areq->src, areq->cryptlen) > 8 ||
                sg_nents_for_len(areq->dst, areq->cryptlen) > 8) {
                algt->stat_fb_sgnum++;
                return true;
        }

        len = areq->cryptlen;
        sg = areq->src;
        while (sg) {
                todo = min(len, sg->length);
                if ((todo % 16) != 0) {
                        algt->stat_fb_sglen++;
                        return true;
                }
                if (!IS_ALIGNED(sg->offset, 16)) {
                        algt->stat_fb_align++;
                        return true;
                }
                len -= todo;
                sg = sg_next(sg);
        }
        len = areq->cryptlen;
        sg = areq->dst;
        while (sg) {
                todo = min(len, sg->length);
                if ((todo % 16) != 0) {
                        algt->stat_fb_sglen++;
                        return true;
                }
                if (!IS_ALIGNED(sg->offset, 16)) {
                        algt->stat_fb_align++;
                        return true;
                }
                len -= todo;
                sg = sg_next(sg);
        }

        /* SS need same numbers of SG (with same length) for source and destination */
        in_sg = areq->src;
        out_sg = areq->dst;
        while (in_sg && out_sg) {
                if (in_sg->length != out_sg->length)
                        return true;
                in_sg = sg_next(in_sg);
                out_sg = sg_next(out_sg);
        }
        if (in_sg || out_sg)
                return true;
        return false;
}

static int sun8i_ss_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_SS_DEBUG)) {
                struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
                struct sun8i_ss_alg_template *algt __maybe_unused;

                algt = container_of(alg, struct sun8i_ss_alg_template,
                                    alg.skcipher.base);

#ifdef CONFIG_CRYPTO_DEV_SUN8I_SS_DEBUG
                algt->stat_fb++;
#endif
        }

        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 & SS_DECRYPTION)
                err = crypto_skcipher_decrypt(&rctx->fallback_req);
        else
                err = crypto_skcipher_encrypt(&rctx->fallback_req);
        return err;
}

static int sun8i_ss_setup_ivs(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ss_dev *ss = op->ss;
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        struct scatterlist *sg = areq->src;
        unsigned int todo, offset;
        unsigned int len = areq->cryptlen;
        unsigned int ivsize = crypto_skcipher_ivsize(tfm);
        struct sun8i_ss_flow *sf = &ss->flows[rctx->flow];
        int i = 0;
        dma_addr_t a;
        int err;

        rctx->ivlen = ivsize;
        if (rctx->op_dir & SS_DECRYPTION) {
                offset = areq->cryptlen - ivsize;
                scatterwalk_map_and_copy(sf->biv, areq->src, offset,
                                         ivsize, 0);
        }

        /* we need to copy all IVs from source in case DMA is bi-directionnal */
        while (sg && len) {
                if (sg->length == 0) {
                        sg = sg_next(sg);
                        continue;
                }
                if (i == 0)
                        memcpy(sf->iv[0], areq->iv, ivsize);
                a = dma_map_single(ss->dev, sf->iv[i], ivsize, DMA_TO_DEVICE);
                if (dma_mapping_error(ss->dev, a)) {
                        memzero_explicit(sf->iv[i], ivsize);
                        dev_err(ss->dev, "Cannot DMA MAP IV\n");
                        err = -EFAULT;
                        goto dma_iv_error;
                }
                rctx->p_iv[i] = a;
                /* we need to setup all others IVs only in the decrypt way */
                if (rctx->op_dir == SS_ENCRYPTION)
                        return 0;
                todo = min(len, sg_dma_len(sg));
                len -= todo;
                i++;
                if (i < MAX_SG) {
                        offset = sg->length - ivsize;
                        scatterwalk_map_and_copy(sf->iv[i], sg, offset, ivsize, 0);
                }
                rctx->niv = i;
                sg = sg_next(sg);
        }

        return 0;
dma_iv_error:
        i--;
        while (i >= 0) {
                dma_unmap_single(ss->dev, rctx->p_iv[i], ivsize, DMA_TO_DEVICE);
                memzero_explicit(sf->iv[i], ivsize);
                i--;
        }
        return err;
}

static int sun8i_ss_cipher(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ss_dev *ss = op->ss;
        struct sun8i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
        struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
        struct sun8i_ss_alg_template *algt;
        struct sun8i_ss_flow *sf = &ss->flows[rctx->flow];
        struct scatterlist *sg;
        unsigned int todo, len, offset, ivsize;
        int nr_sgs = 0;
        int nr_sgd = 0;
        int err = 0;
        int nsgs = sg_nents_for_len(areq->src, areq->cryptlen);
        int nsgd = sg_nents_for_len(areq->dst, areq->cryptlen);
        int i;

        algt = container_of(alg, struct sun8i_ss_alg_template, alg.skcipher.base);

        dev_dbg(ss->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);

#ifdef CONFIG_CRYPTO_DEV_SUN8I_SS_DEBUG
        algt->stat_req++;
#endif

        rctx->op_mode = ss->variant->op_mode[algt->ss_blockmode];
        rctx->method = ss->variant->alg_cipher[algt->ss_algo_id];
        rctx->keylen = op->keylen;

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

        ivsize = crypto_skcipher_ivsize(tfm);
        if (areq->iv && crypto_skcipher_ivsize(tfm) > 0) {
                err = sun8i_ss_setup_ivs(areq);
                if (err)
                        goto theend_key;
        }
        if (areq->src == areq->dst) {
                nr_sgs = dma_map_sg(ss->dev, areq->src, nsgs, DMA_BIDIRECTIONAL);
                if (nr_sgs <= 0 || nr_sgs > 8) {
                        dev_err(ss->dev, "Invalid sg number %d\n", nr_sgs);
                        err = -EINVAL;
                        goto theend_iv;
                }
                nr_sgd = nr_sgs;
        } else {
                nr_sgs = dma_map_sg(ss->dev, areq->src, nsgs, DMA_TO_DEVICE);
                if (nr_sgs <= 0 || nr_sgs > 8) {
                        dev_err(ss->dev, "Invalid sg number %d\n", nr_sgs);
                        err = -EINVAL;
                        goto theend_iv;
                }
                nr_sgd = dma_map_sg(ss->dev, areq->dst, nsgd, DMA_FROM_DEVICE);
                if (nr_sgd <= 0 || nr_sgd > 8) {
                        dev_err(ss->dev, "Invalid sg number %d\n", nr_sgd);
                        err = -EINVAL;
                        goto theend_sgs;
                }
        }

        len = areq->cryptlen;
        i = 0;
        sg = areq->src;
        while (i < nr_sgs && sg && len) {
                if (sg_dma_len(sg) == 0)
                        goto sgs_next;
                rctx->t_src[i].addr = sg_dma_address(sg);
                todo = min(len, sg_dma_len(sg));
                rctx->t_src[i].len = todo / 4;
                dev_dbg(ss->dev, "%s total=%u SGS(%d %u off=%d) todo=%u\n", __func__,
                        areq->cryptlen, i, rctx->t_src[i].len, sg->offset, todo);
                len -= todo;
                i++;
sgs_next:
                sg = sg_next(sg);
        }
        if (len > 0) {
                dev_err(ss->dev, "remaining len %d\n", len);
                err = -EINVAL;
                goto theend_sgs;
        }

        len = areq->cryptlen;
        i = 0;
        sg = areq->dst;
        while (i < nr_sgd && sg && len) {
                if (sg_dma_len(sg) == 0)
                        goto sgd_next;
                rctx->t_dst[i].addr = sg_dma_address(sg);
                todo = min(len, sg_dma_len(sg));
                rctx->t_dst[i].len = todo / 4;
                dev_dbg(ss->dev, "%s total=%u SGD(%d %u off=%d) todo=%u\n", __func__,
                        areq->cryptlen, i, rctx->t_dst[i].len, sg->offset, todo);
                len -= todo;
                i++;
sgd_next:
                sg = sg_next(sg);
        }
        if (len > 0) {
                dev_err(ss->dev, "remaining len %d\n", len);
                err = -EINVAL;
                goto theend_sgs;
        }

        err = sun8i_ss_run_task(ss, rctx, crypto_tfm_alg_name(areq->base.tfm));

theend_sgs:
        if (areq->src == areq->dst) {
                dma_unmap_sg(ss->dev, areq->src, nsgs, DMA_BIDIRECTIONAL);
        } else {
                dma_unmap_sg(ss->dev, areq->src, nsgs, DMA_TO_DEVICE);
                dma_unmap_sg(ss->dev, areq->dst, nsgd, DMA_FROM_DEVICE);
        }

theend_iv:
        if (areq->iv && ivsize > 0) {
                for (i = 0; i < rctx->niv; i++) {
                        dma_unmap_single(ss->dev, rctx->p_iv[i], ivsize, DMA_TO_DEVICE);
                        memzero_explicit(sf->iv[i], ivsize);
                }

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

theend_key:
        dma_unmap_single(ss->dev, rctx->p_key, op->keylen, DMA_TO_DEVICE);

theend:

        return err;
}

int sun8i_ss_handle_cipher_request(struct crypto_engine *engine, void *areq)
{
        int err;
        struct skcipher_request *breq = container_of(areq, struct skcipher_request, base);

        err = sun8i_ss_cipher(breq);
        local_bh_disable();
        crypto_finalize_skcipher_request(engine, breq, err);
        local_bh_enable();

        return 0;
}

int sun8i_ss_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;

        memset(rctx, 0, sizeof(struct sun8i_cipher_req_ctx));
        rctx->op_dir = SS_DECRYPTION;

        if (sun8i_ss_need_fallback(areq))
                return sun8i_ss_cipher_fallback(areq);

        e = sun8i_ss_get_engine_number(op->ss);
        engine = op->ss->flows[e].engine;
        rctx->flow = e;

        return crypto_transfer_skcipher_request_to_engine(engine, areq);
}

int sun8i_ss_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;

        memset(rctx, 0, sizeof(struct sun8i_cipher_req_ctx));
        rctx->op_dir = SS_ENCRYPTION;

        if (sun8i_ss_need_fallback(areq))
                return sun8i_ss_cipher_fallback(areq);

        e = sun8i_ss_get_engine_number(op->ss);
        engine = op->ss->flows[e].engine;
        rctx->flow = e;

        return crypto_transfer_skcipher_request_to_engine(engine, areq);
}

int sun8i_ss_cipher_init(struct crypto_tfm *tfm)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_tfm_ctx(tfm);
        struct sun8i_ss_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_ss_alg_template, alg.skcipher.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(sktfm, sizeof(struct sun8i_cipher_req_ctx) +
                                    crypto_skcipher_reqsize(op->fallback_tfm));

        memcpy(algt->fbname,
               crypto_tfm_alg_driver_name(crypto_skcipher_tfm(op->fallback_tfm)),
               CRYPTO_MAX_ALG_NAME);

        err = pm_runtime_resume_and_get(op->ss->dev);
        if (err < 0) {
                dev_err(op->ss->dev, "pm error %d\n", err);
                goto error_pm;
        }

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

void sun8i_ss_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(op->ss->dev);
}

int sun8i_ss_aes_setkey(struct crypto_skcipher *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ss_dev *ss = op->ss;

        switch (keylen) {
        case 128 / 8:
                break;
        case 192 / 8:
                break;
        case 256 / 8:
                break;
        default:
                dev_dbg(ss->dev, "ERROR: Invalid keylen %u\n", keylen);
                return -EINVAL;
        }
        kfree_sensitive(op->key);
        op->keylen = keylen;
        op->key = kmemdup(key, keylen, GFP_KERNEL);
        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_ss_des3_setkey(struct crypto_skcipher *tfm, const u8 *key,
                         unsigned int keylen)
{
        struct sun8i_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun8i_ss_dev *ss = op->ss;

        if (unlikely(keylen != 3 * DES_KEY_SIZE)) {
                dev_dbg(ss->dev, "Invalid keylen %u\n", keylen);
                return -EINVAL;
        }

        kfree_sensitive(op->key);
        op->keylen = keylen;
        op->key = kmemdup(key, keylen, GFP_KERNEL);
        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);
}