Re: [PATCHv6 2/7] crypto: sa2ul: Add crypto driver

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On 22/08/2020 01:17, Nathan Chancellor wrote:
On Mon, Jul 13, 2020 at 11:34:22AM +0300, Tero Kristo wrote:
From: Keerthy <j-keerthy@xxxxxx>

Adds a basic crypto driver and currently supports AES/3DES
in cbc mode for both encryption and decryption.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
[t-kristo@xxxxxx: major re-work to fix various bugs in the driver and to
  cleanup the code]
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
  drivers/crypto/Kconfig  |   14 +
  drivers/crypto/Makefile |    1 +
  drivers/crypto/sa2ul.c  | 1388 +++++++++++++++++++++++++++++++++++++++
  drivers/crypto/sa2ul.h  |  380 +++++++++++
  4 files changed, 1783 insertions(+)
  create mode 100644 drivers/crypto/sa2ul.c
  create mode 100644 drivers/crypto/sa2ul.h

<snip>

diff --git a/drivers/crypto/sa2ul.c b/drivers/crypto/sa2ul.c
new file mode 100644
index 000000000000..860c7435fefa
--- /dev/null
+++ b/drivers/crypto/sa2ul.c
@@ -0,0 +1,1388 @@

<snip>

+static int sa_run(struct sa_req *req)
+{
+	struct sa_rx_data *rxd;
+	gfp_t gfp_flags;
+	u32 cmdl[SA_MAX_CMDL_WORDS];
+	struct sa_crypto_data *pdata = dev_get_drvdata(sa_k3_dev);
+	struct device *ddev;
+	struct dma_chan *dma_rx;
+	int sg_nents, src_nents, dst_nents;
+	int mapped_src_nents, mapped_dst_nents;
+	struct scatterlist *src, *dst;
+	size_t pl, ml, split_size;
+	struct sa_ctx_info *sa_ctx = req->enc ? &req->ctx->enc : &req->ctx->dec;
+	int ret;
+	struct dma_async_tx_descriptor *tx_out;
+	u32 *mdptr;
+	bool diff_dst;
+	enum dma_data_direction dir_src;
+
+	gfp_flags = req->base->flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
+		GFP_KERNEL : GFP_ATOMIC;
+
+	rxd = kzalloc(sizeof(*rxd), gfp_flags);
+	if (!rxd)
+		return -ENOMEM;
+
+	if (req->src != req->dst) {
+		diff_dst = true;
+		dir_src = DMA_TO_DEVICE;
+	} else {
+		diff_dst = false;
+		dir_src = DMA_BIDIRECTIONAL;
+	}
+
+	/*
+	 * SA2UL has an interesting feature where the receive DMA channel
+	 * is selected based on the data passed to the engine. Within the
+	 * transition range, there is also a space where it is impossible
+	 * to determine where the data will end up, and this should be
+	 * avoided. This will be handled by the SW fallback mechanism by
+	 * the individual algorithm implementations.
+	 */
+	if (req->size >= 256)
+		dma_rx = pdata->dma_rx2;
+	else
+		dma_rx = pdata->dma_rx1;
+
+	ddev = dma_rx->device->dev;
+
+	memcpy(cmdl, sa_ctx->cmdl, sa_ctx->cmdl_size);
+
+	sa_update_cmdl(req, cmdl, &sa_ctx->cmdl_upd_info);
+
+	if (req->type != CRYPTO_ALG_TYPE_AHASH) {
+		if (req->enc)
+			req->type |=
+				(SA_REQ_SUBTYPE_ENC << SA_REQ_SUBTYPE_SHIFT);
+		else
+			req->type |=
+				(SA_REQ_SUBTYPE_DEC << SA_REQ_SUBTYPE_SHIFT);
+	}
+
+	cmdl[sa_ctx->cmdl_size / sizeof(u32)] = req->type;
+
+	/*
+	 * Map the packets, first we check if the data fits into a single
+	 * sg entry and use that if possible. If it does not fit, we check
+	 * if we need to do sg_split to align the scatterlist data on the
+	 * actual data size being processed by the crypto engine.
+	 */
+	src = req->src;
+	sg_nents = sg_nents_for_len(src, req->size);
+
+	split_size = req->size;
+
+	if (sg_nents == 1 && split_size <= req->src->length) {
+		src = &rxd->rx_sg;
+		sg_init_table(src, 1);
+		sg_set_page(src, sg_page(req->src), split_size,
+			    req->src->offset);
+		src_nents = 1;
+		dma_map_sg(ddev, src, sg_nents, dir_src);
+	} else {
+		mapped_src_nents = dma_map_sg(ddev, req->src, sg_nents,
+					      dir_src);
+		ret = sg_split(req->src, mapped_src_nents, 0, 1, &split_size,
+			       &src, &src_nents, gfp_flags);
+		if (ret) {
+			src_nents = sg_nents;
+			src = req->src;
+		} else {
+			rxd->split_src_sg = src;
+		}
+	}
+
+	if (!diff_dst) {
+		dst_nents = src_nents;
+		dst = src;
+	} else {
+		dst_nents = sg_nents_for_len(req->dst, req->size);
+
+		if (dst_nents == 1 && split_size <= req->dst->length) {
+			dst = &rxd->tx_sg;
+			sg_init_table(dst, 1);
+			sg_set_page(dst, sg_page(req->dst), split_size,
+				    req->dst->offset);
+			dst_nents = 1;
+			dma_map_sg(ddev, dst, dst_nents, DMA_FROM_DEVICE);
+		} else {
+			mapped_dst_nents = dma_map_sg(ddev, req->dst, dst_nents,
+						      DMA_FROM_DEVICE);
+			ret = sg_split(req->dst, mapped_dst_nents, 0, 1,
+				       &split_size, &dst, &dst_nents,
+				       gfp_flags);
+			if (ret) {
+				dst_nents = dst_nents;

This causes a clang warning:

drivers/crypto/sa2ul.c:1152:15: warning: explicitly assigning value of
variable of type 'int' to itself [-Wself-assign]
                                 dst_nents = dst_nents;
                                 ~~~~~~~~~ ^ ~~~~~~~~~
1 warning generated.

Was the right side supposed to be something else? Otherwise, this line
can be removed, right?

This is definitely a bug in the code, thanks for catching. I'll check what this was actually supposed to be and fix... Too many iterations of the code behind.

-Tero


+				dst = req->dst;
+			} else {
+				rxd->split_dst_sg = dst;
+			}
+		}
+	}
+
+	if (unlikely(src_nents != sg_nents)) {
+		dev_warn_ratelimited(sa_k3_dev, "failed to map tx pkt\n");
+		ret = -EIO;
+		goto err_cleanup;
+	}
+
+	rxd->tx_in = dmaengine_prep_slave_sg(dma_rx, dst, dst_nents,
+					     DMA_DEV_TO_MEM,
+					     DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!rxd->tx_in) {
+		dev_err(pdata->dev, "IN prep_slave_sg() failed\n");
+		ret = -EINVAL;
+		goto err_cleanup;
+	}
+
+	rxd->req = (void *)req->base;
+	rxd->enc = req->enc;
+	rxd->ddev = ddev;
+	rxd->src = src;
+	rxd->dst = dst;
+	rxd->iv_idx = req->ctx->iv_idx;
+	rxd->enc_iv_size = sa_ctx->cmdl_upd_info.enc_iv.size;
+	rxd->tx_in->callback = req->callback;
+	rxd->tx_in->callback_param = rxd;
+
+	tx_out = dmaengine_prep_slave_sg(pdata->dma_tx, src,
+					 src_nents, DMA_MEM_TO_DEV,
+					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+
+	if (!tx_out) {
+		dev_err(pdata->dev, "OUT prep_slave_sg() failed\n");
+		ret = -EINVAL;
+		goto err_cleanup;
+	}
+
+	/*
+	 * Prepare metadata for DMA engine. This essentially describes the
+	 * crypto algorithm to be used, data sizes, different keys etc.
+	 */
+	mdptr = (u32 *)dmaengine_desc_get_metadata_ptr(tx_out, &pl, &ml);
+
+	sa_prepare_tx_desc(mdptr, (sa_ctx->cmdl_size + (SA_PSDATA_CTX_WORDS *
+				   sizeof(u32))), cmdl, sizeof(sa_ctx->epib),
+			   sa_ctx->epib);
+
+	ml = sa_ctx->cmdl_size + (SA_PSDATA_CTX_WORDS * sizeof(u32));
+	dmaengine_desc_set_metadata_len(tx_out, req->mdata_size);
+
+	dmaengine_submit(tx_out);
+	dmaengine_submit(rxd->tx_in);
+
+	dma_async_issue_pending(dma_rx);
+	dma_async_issue_pending(pdata->dma_tx);
+
+	return -EINPROGRESS;
+
+err_cleanup:
+	dma_unmap_sg(ddev, req->src, sg_nents, DMA_TO_DEVICE);
+	kfree(rxd->split_src_sg);
+
+	if (req->src != req->dst) {
+		dst_nents = sg_nents_for_len(req->dst, req->size);
+		dma_unmap_sg(ddev, req->dst, dst_nents, DMA_FROM_DEVICE);
+		kfree(rxd->split_dst_sg);
+	}
+
+	kfree(rxd);
+
+	return ret;
+}

Cheers,
Nathan


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