static int sl3516_ce_cipher()

in gemini/sl3516-ce-cipher.c [123:259]

• 123 lines of code
• 17 McCabe index (conditional complexity)

static int sl3516_ce_cipher(struct skcipher_request *areq)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
	struct sl3516_ce_cipher_tfm_ctx *op = crypto_skcipher_ctx(tfm);
	struct sl3516_ce_dev *ce = op->ce;
	struct sl3516_ce_cipher_req_ctx *rctx = skcipher_request_ctx(areq);
	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
	struct sl3516_ce_alg_template *algt;
	struct scatterlist *sg;
	unsigned int todo, len;
	struct pkt_control_ecb *ecb;
	int nr_sgs = 0;
	int nr_sgd = 0;
	int err = 0;
	int i;

	algt = container_of(alg, struct sl3516_ce_alg_template, alg.skcipher);

	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);

	algt->stat_req++;

	if (areq->src == areq->dst) {
		nr_sgs = dma_map_sg(ce->dev, areq->src, sg_nents(areq->src),
				    DMA_BIDIRECTIONAL);
		if (nr_sgs <= 0 || nr_sgs > MAXDESC / 2) {
			dev_err(ce->dev, "Invalid sg number %d\n", nr_sgs);
			err = -EINVAL;
			goto theend;
		}
		nr_sgd = nr_sgs;
	} else {
		nr_sgs = dma_map_sg(ce->dev, areq->src, sg_nents(areq->src),
				    DMA_TO_DEVICE);
		if (nr_sgs <= 0 || nr_sgs > MAXDESC / 2) {
			dev_err(ce->dev, "Invalid sg number %d\n", nr_sgs);
			err = -EINVAL;
			goto theend;
		}
		nr_sgd = dma_map_sg(ce->dev, areq->dst, sg_nents(areq->dst),
				    DMA_FROM_DEVICE);
		if (nr_sgd <= 0 || nr_sgd > MAXDESC) {
			dev_err(ce->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;
		dev_dbg(ce->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(ce->dev, "remaining len %d/%u nr_sgs=%d\n", len, areq->cryptlen, nr_sgs);
		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;
		dev_dbg(ce->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(ce->dev, "remaining len %d\n", len);
		err = -EINVAL;
		goto theend_sgs;
	}

	switch (algt->mode) {
	case ECB_AES:
		rctx->pctrllen = sizeof(struct pkt_control_ecb);
		ecb = (struct pkt_control_ecb *)ce->pctrl;

		rctx->tqflag = TQ0_TYPE_CTRL;
		rctx->tqflag |= TQ1_CIPHER;
		ecb->control.op_mode = rctx->op_dir;
		ecb->control.cipher_algorithm = ECB_AES;
		ecb->cipher.header_len = 0;
		ecb->cipher.algorithm_len = areq->cryptlen;
		cpu_to_be32_array((__be32 *)ecb->key, (u32 *)op->key, op->keylen / 4);
		rctx->h = &ecb->cipher;

		rctx->tqflag |= TQ4_KEY0;
		rctx->tqflag |= TQ5_KEY4;
		rctx->tqflag |= TQ6_KEY6;
		ecb->control.aesnk = op->keylen / 4;
		break;
	}

	rctx->nr_sgs = nr_sgs;
	rctx->nr_sgd = nr_sgd;
	err = sl3516_ce_run_task(ce, rctx, crypto_tfm_alg_name(areq->base.tfm));

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

theend:

	return err;
}