static int sun8i_ss_cipher()

in allwinner/sun8i-ss/sun8i-ss-cipher.c [95:269]

• 160 lines of code
• 28 McCabe index (conditional complexity)

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 scatterlist *sg;
	unsigned int todo, len, offset, ivsize;
	void *backup_iv = NULL;
	int nr_sgs = 0;
	int nr_sgd = 0;
	int err = 0;
	int i;

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

	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) {
		rctx->ivlen = ivsize;
		rctx->biv = kzalloc(ivsize, GFP_KERNEL | GFP_DMA);
		if (!rctx->biv) {
			err = -ENOMEM;
			goto theend_key;
		}
		if (rctx->op_dir & SS_DECRYPTION) {
			backup_iv = kzalloc(ivsize, GFP_KERNEL);
			if (!backup_iv) {
				err = -ENOMEM;
				goto theend_key;
			}
			offset = areq->cryptlen - ivsize;
			scatterwalk_map_and_copy(backup_iv, areq->src, offset,
						 ivsize, 0);
		}
		memcpy(rctx->biv, areq->iv, ivsize);
		rctx->p_iv = dma_map_single(ss->dev, rctx->biv, rctx->ivlen,
					    DMA_TO_DEVICE);
		if (dma_mapping_error(ss->dev, rctx->p_iv)) {
			dev_err(ss->dev, "Cannot DMA MAP IV\n");
			err = -ENOMEM;
			goto theend_iv;
		}
	}
	if (areq->src == areq->dst) {
		nr_sgs = dma_map_sg(ss->dev, areq->src, sg_nents(areq->src),
				    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, sg_nents(areq->src),
				    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, sg_nents(areq->dst),
				    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, sg_nents(areq->src),
			     DMA_BIDIRECTIONAL);
	} else {
		dma_unmap_sg(ss->dev, areq->src, sg_nents(areq->src),
			     DMA_TO_DEVICE);
		dma_unmap_sg(ss->dev, areq->dst, sg_nents(areq->dst),
			     DMA_FROM_DEVICE);
	}

theend_iv:
	if (rctx->p_iv)
		dma_unmap_single(ss->dev, rctx->p_iv, rctx->ivlen,
				 DMA_TO_DEVICE);

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

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

theend:

	return err;
}