[4/8] crypto: omap-sham: add support functions for sg based data handling

diff --git a/drivers/crypto/omap-sham.c b/drivers/crypto/omap-sham.c
index 33bea52..8558989 100644
--- a/drivers/crypto/omap-sham.c
+++ b/drivers/crypto/omap-sham.c
@@ -112,6 +112,8 @@ 
 #define FLAGS_DMA_READY		6
 #define FLAGS_AUTO_XOR		7
 #define FLAGS_BE32_SHA1		8
+#define FLAGS_SGS_COPIED	9
+#define FLAGS_SGS_ALLOCED	10
 /* context flags */
 #define FLAGS_FINUP		16
 #define FLAGS_SG		17
@@ -151,8 +153,10 @@  struct omap_sham_reqctx {
 
 	/* walk state */
 	struct scatterlist	*sg;
+	struct scatterlist	sgl[2];
 	struct scatterlist	sgl_tmp;
 	unsigned int		offset;	/* offset in current sg */
+	int			sg_len;
 	unsigned int		total;	/* total request */
 
 	u8			buffer[0] OMAP_ALIGNED;
@@ -223,6 +227,7 @@  struct omap_sham_dev {
 	struct dma_chan		*dma_lch;
 	struct tasklet_struct	done_task;
 	u8			polling_mode;
+	u8			xmit_buf[BUFLEN];
 
 	unsigned long		flags;
 	struct crypto_queue	queue;
@@ -626,6 +631,260 @@  static int omap_sham_xmit_dma(struct omap_sham_dev *dd, dma_addr_t dma_addr,
 	return -EINPROGRESS;
 }
 
+static int omap_sham_copy_sg_lists(struct omap_sham_reqctx *ctx,
+				   struct scatterlist *sg, int bs, int new_len)
+{
+	int n = sg_nents(sg);
+	struct scatterlist *tmp;
+	int offset = ctx->offset;
+
+	if (ctx->bufcnt)
+		n++;
+
+	ctx->sg = kmalloc_array(n, sizeof(*sg), GFP_KERNEL);
+	if (!ctx->sg)
+		return -ENOMEM;
+
+	sg_init_table(ctx->sg, n);
+
+	tmp = ctx->sg;
+
+	ctx->sg_len = 0;
+
+	if (ctx->bufcnt) {
+		sg_set_buf(tmp, ctx->dd->xmit_buf, ctx->bufcnt);
+		tmp = sg_next(tmp);
+		ctx->sg_len++;
+	}
+
+	while (sg && new_len) {
+		int len = sg->length - offset;
+
+		if (offset) {
+			offset -= sg->length;
+			if (offset < 0)
+				offset = 0;
+		}
+
+		if (new_len < len)
+			len = new_len;
+
+		if (len > 0) {
+			new_len -= len;
+			sg_set_page(tmp, sg_page(sg), len, sg->offset);
+			if (new_len <= 0)
+				sg_mark_end(tmp);
+			tmp = sg_next(tmp);
+			ctx->sg_len++;
+		}
+
+		sg = sg_next(sg);
+	}
+
+	set_bit(FLAGS_SGS_ALLOCED, &ctx->dd->flags);
+
+	ctx->bufcnt = 0;
+
+	return 0;
+}
+
+static int omap_sham_copy_sgs(struct omap_sham_reqctx *ctx,
+			      struct scatterlist *sg, int bs, int new_len)
+{
+	int pages;
+	void *buf;
+	int len;
+
+	len = new_len + ctx->bufcnt;
+
+	pages = get_order(ctx->total);
+
+	buf = (void *)__get_free_pages(GFP_ATOMIC, pages);
+	if (!buf) {
+		pr_err("Couldn't allocate pages for unaligned cases.\n");
+		return -ENOMEM;
+	}
+
+	if (ctx->bufcnt)
+		memcpy(buf, ctx->dd->xmit_buf, ctx->bufcnt);
+
+	scatterwalk_map_and_copy(buf + ctx->bufcnt, sg, ctx->offset,
+				 ctx->total - ctx->bufcnt, 0);
+	sg_init_table(ctx->sgl, 1);
+	sg_set_buf(ctx->sgl, buf, len);
+	ctx->sg = ctx->sgl;
+	set_bit(FLAGS_SGS_COPIED, &ctx->dd->flags);
+	ctx->sg_len = 1;
+	ctx->bufcnt = 0;
+	ctx->offset = 0;
+
+	return 0;
+}
+
+static int omap_sham_align_sgs(struct scatterlist *sg,
+			       int nbytes, int bs, bool final,
+			       struct omap_sham_reqctx *rctx)
+{
+	int n = 0;
+	bool aligned = true;
+	bool list_ok = true;
+	struct scatterlist *sg_tmp = sg;
+	int new_len;
+	int offset = rctx->offset;
+
+	if (!sg || !sg->length || !nbytes)
+		return 0;
+
+	new_len = nbytes;
+
+	if (offset)
+		list_ok = false;
+
+	if (final)
+		new_len = DIV_ROUND_UP(new_len, bs) * bs;
+	else
+		new_len = new_len / bs * bs;
+
+	while (nbytes > 0 && sg_tmp) {
+		n++;
+
+		if (offset < sg_tmp->length) {
+			if (!IS_ALIGNED(offset + sg_tmp->offset, 4)) {
+				aligned = false;
+				break;
+			}
+
+			if (!IS_ALIGNED(sg_tmp->length - offset, bs)) {
+				aligned = false;
+				break;
+			}
+		}
+
+		if (offset) {
+			offset -= sg_tmp->length;
+			if (offset < 0) {
+				nbytes += offset;
+				offset = 0;
+			}
+		} else {
+			nbytes -= sg_tmp->length;
+		}
+
+		sg_tmp = sg_next(sg_tmp);
+
+		if (nbytes < 0) {
+			list_ok = false;
+			break;
+		}
+	}
+
+	if (!aligned)
+		return omap_sham_copy_sgs(rctx, sg, bs, new_len);
+	else if (!list_ok)
+		return omap_sham_copy_sg_lists(rctx, sg, bs, new_len);
+
+	rctx->sg_len = n;
+	rctx->sg = sg;
+
+	return 0;
+}
+
+static int omap_sham_prepare_request(struct ahash_request *req, bool update)
+{
+	struct omap_sham_reqctx *rctx = ahash_request_ctx(req);
+	int bs;
+	int ret;
+	int nbytes;
+	bool final = rctx->flags & BIT(FLAGS_FINUP);
+	int xmit_len, hash_later;
+
+	if (!req)
+		return 0;
+
+	bs = get_block_size(rctx);
+
+	if (update)
+		nbytes = req->nbytes;
+	else
+		nbytes = 0;
+
+	rctx->total = nbytes + rctx->bufcnt;
+
+	if (!rctx->total)
+		return 0;
+
+	if (nbytes && (!IS_ALIGNED(rctx->bufcnt, bs))) {
+		int len = bs - rctx->bufcnt % bs;
+
+		if (len > nbytes)
+			len = nbytes;
+		scatterwalk_map_and_copy(rctx->buffer + rctx->bufcnt, req->src,
+					 0, len, 0);
+		rctx->bufcnt += len;
+		nbytes -= len;
+		rctx->offset = len;
+	}
+
+	if (rctx->bufcnt)
+		memcpy(rctx->dd->xmit_buf, rctx->buffer, rctx->bufcnt);
+
+	ret = omap_sham_align_sgs(req->src, nbytes, bs, final, rctx);
+	if (ret)
+		return ret;
+
+	xmit_len = rctx->total;
+
+	if (!IS_ALIGNED(xmit_len, bs)) {
+		if (final)
+			xmit_len = DIV_ROUND_UP(xmit_len, bs) * bs;
+		else
+			xmit_len = xmit_len / bs * bs;
+	}
+
+	hash_later = rctx->total - xmit_len;
+	if (hash_later < 0)
+		hash_later = 0;
+
+	if (rctx->bufcnt && nbytes) {
+		/* have data from previous operation and current */
+		sg_init_table(rctx->sgl, 2);
+		sg_set_buf(rctx->sgl, rctx->dd->xmit_buf, rctx->bufcnt);
+
+		sg_chain(rctx->sgl, 2, req->src);
+
+		rctx->sg = rctx->sgl;
+
+		rctx->sg_len++;
+	} else if (rctx->bufcnt) {
+		/* have buffered data only */
+		sg_init_table(rctx->sgl, 1);
+		sg_set_buf(rctx->sgl, rctx->dd->xmit_buf, xmit_len);
+
+		rctx->sg = rctx->sgl;
+
+		rctx->sg_len = 1;
+	}
+
+	if (hash_later) {
+		if (req->nbytes) {
+			scatterwalk_map_and_copy(rctx->buffer, req->src,
+						 req->nbytes - hash_later,
+						 hash_later, 0);
+		} else {
+			memcpy(rctx->buffer, rctx->buffer + xmit_len,
+			       hash_later);
+		}
+		rctx->bufcnt = hash_later;
+	} else {
+		rctx->bufcnt = 0;
+	}
+
+	if (!final)
+		rctx->total = xmit_len;
+
+	return 0;
+}
+
 static size_t omap_sham_append_buffer(struct omap_sham_reqctx *ctx,
 				const u8 *data, size_t length)
 {
@@ -1040,6 +1299,10 @@  retry:
 	dd->req = req;
 	ctx = ahash_request_ctx(req);
 
+	err = omap_sham_prepare_request(NULL, ctx->op == OP_UPDATE);
+	if (err)
+		goto err1;
+
 	dev_dbg(dd->dev, "handling new req, op: %lu, nbytes: %d\n",
 						ctx->op, req->nbytes);