1 files changed, 261 insertions, 207 deletions

diff --git a/drivers/crypto/omap-aes.c b/drivers/crypto/omap-aes.c
index 5f7980586850..ce791c2f81f7 100644
--- a/drivers/crypto/omap-aes.c
+++ b/drivers/crypto/omap-aes.c
@@ -13,7 +13,9 @@
  *
  */
 
-#define pr_fmt(fmt) "%s: " fmt, __func__
+#define pr_fmt(fmt) "%20s: " fmt, __func__
+#define prn(num) pr_debug(#num "=%d\n", num)
+#define prx(num) pr_debug(#num "=%x\n", num)
 
 #include <linux/err.h>
 #include <linux/module.h>
@@ -38,6 +40,8 @@
 #define DST_MAXBURST			4
 #define DMA_MIN				(DST_MAXBURST * sizeof(u32))
 
+#define _calc_walked(inout) (dd->inout##_walk.offset - dd->inout##_sg->offset)
+
 /* OMAP TRM gives bitfields as start:end, where start is the higher bit
    number. For example 7:0 */
 #define FLD_MASK(start, end)	(((1 << ((start) - (end) + 1)) - 1) << (end))
@@ -74,6 +78,10 @@
 
 #define AES_REG_LENGTH_N(x)		(0x54 + ((x) * 0x04))
 
+#define AES_REG_IRQ_STATUS(dd)         ((dd)->pdata->irq_status_ofs)
+#define AES_REG_IRQ_ENABLE(dd)         ((dd)->pdata->irq_enable_ofs)
+#define AES_REG_IRQ_DATA_IN            BIT(1)
+#define AES_REG_IRQ_DATA_OUT           BIT(2)
 #define DEFAULT_TIMEOUT		(5*HZ)
 
 #define FLAGS_MODE_MASK		0x000f
@@ -86,6 +94,8 @@
 #define FLAGS_FAST		BIT(5)
 #define FLAGS_BUSY		BIT(6)
 
+#define AES_BLOCK_WORDS		(AES_BLOCK_SIZE >> 2)
+
 struct omap_aes_ctx {
 	struct omap_aes_dev *dd;
 
@@ -119,6 +129,8 @@ struct omap_aes_pdata {
 	u32		data_ofs;
 	u32		rev_ofs;
 	u32		mask_ofs;
+	u32             irq_enable_ofs;
+	u32             irq_status_ofs;
 
 	u32		dma_enable_in;
 	u32		dma_enable_out;
@@ -146,25 +158,32 @@ struct omap_aes_dev {
 	struct tasklet_struct	queue_task;
 
 	struct ablkcipher_request	*req;
+
+	/*
+	 * total is used by PIO mode for book keeping so introduce
+	 * variable total_save as need it to calc page_order
+	 */
 	size_t				total;
+	size_t				total_save;
+
 	struct scatterlist		*in_sg;
-	struct scatterlist		in_sgl;
-	size_t				in_offset;
 	struct scatterlist		*out_sg;
+
+	/* Buffers for copying for unaligned cases */
+	struct scatterlist		in_sgl;
 	struct scatterlist		out_sgl;
-	size_t				out_offset;
+	struct scatterlist		*orig_out;
+	int				sgs_copied;
 
-	size_t			buflen;
-	void			*buf_in;
-	size_t			dma_size;
+	struct scatter_walk		in_walk;
+	struct scatter_walk		out_walk;
 	int			dma_in;
 	struct dma_chan		*dma_lch_in;
-	dma_addr_t		dma_addr_in;
-	void			*buf_out;
 	int			dma_out;
 	struct dma_chan		*dma_lch_out;
-	dma_addr_t		dma_addr_out;
-
+	int			in_sg_len;
+	int			out_sg_len;
+	int			pio_only;
 	const struct omap_aes_pdata	*pdata;
 };
 
@@ -172,16 +191,36 @@ struct omap_aes_dev {
 static LIST_HEAD(dev_list);
 static DEFINE_SPINLOCK(list_lock);
 
+#ifdef DEBUG
+#define omap_aes_read(dd, offset)				\
+({								\
+	int _read_ret;						\
+	_read_ret = __raw_readl(dd->io_base + offset);		\
+	pr_debug("omap_aes_read(" #offset "=%#x)= %#x\n",	\
+		 offset, _read_ret);				\
+	_read_ret;						\
+})
+#else
 static inline u32 omap_aes_read(struct omap_aes_dev *dd, u32 offset)
 {
 	return __raw_readl(dd->io_base + offset);
 }
+#endif
 
+#ifdef DEBUG
+#define omap_aes_write(dd, offset, value)				\
+	do {								\
+		pr_debug("omap_aes_write(" #offset "=%#x) value=%#x\n",	\
+			 offset, value);				\
+		__raw_writel(value, dd->io_base + offset);		\
+	} while (0)
+#else
 static inline void omap_aes_write(struct omap_aes_dev *dd, u32 offset,
 				  u32 value)
 {
 	__raw_writel(value, dd->io_base + offset);
 }
+#endif
 
 static inline void omap_aes_write_mask(struct omap_aes_dev *dd, u32 offset,
 					u32 value, u32 mask)
@@ -323,33 +362,6 @@ static int omap_aes_dma_init(struct omap_aes_dev *dd)
 	dd->dma_lch_out = NULL;
 	dd->dma_lch_in = NULL;
 
-	dd->buf_in = (void *)__get_free_pages(GFP_KERNEL, OMAP_AES_CACHE_SIZE);
-	dd->buf_out = (void *)__get_free_pages(GFP_KERNEL, OMAP_AES_CACHE_SIZE);
-	dd->buflen = PAGE_SIZE << OMAP_AES_CACHE_SIZE;
-	dd->buflen &= ~(AES_BLOCK_SIZE - 1);
-
-	if (!dd->buf_in || !dd->buf_out) {
-		dev_err(dd->dev, "unable to alloc pages.\n");
-		goto err_alloc;
-	}
-
-	/* MAP here */
-	dd->dma_addr_in = dma_map_single(dd->dev, dd->buf_in, dd->buflen,
-					 DMA_TO_DEVICE);
-	if (dma_mapping_error(dd->dev, dd->dma_addr_in)) {
-		dev_err(dd->dev, "dma %d bytes error\n", dd->buflen);
-		err = -EINVAL;
-		goto err_map_in;
-	}
-
-	dd->dma_addr_out = dma_map_single(dd->dev, dd->buf_out, dd->buflen,
-					  DMA_FROM_DEVICE);
-	if (dma_mapping_error(dd->dev, dd->dma_addr_out)) {
-		dev_err(dd->dev, "dma %d bytes error\n", dd->buflen);
-		err = -EINVAL;
-		goto err_map_out;
-	}
-
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
 
@@ -376,14 +388,6 @@ static int omap_aes_dma_init(struct omap_aes_dev *dd)
 err_dma_out:
 	dma_release_channel(dd->dma_lch_in);
 err_dma_in:
-	dma_unmap_single(dd->dev, dd->dma_addr_out, dd->buflen,
-			 DMA_FROM_DEVICE);
-err_map_out:
-	dma_unmap_single(dd->dev, dd->dma_addr_in, dd->buflen, DMA_TO_DEVICE);
-err_map_in:
-	free_pages((unsigned long)dd->buf_out, OMAP_AES_CACHE_SIZE);
-	free_pages((unsigned long)dd->buf_in, OMAP_AES_CACHE_SIZE);
-err_alloc:
 	if (err)
 		pr_err("error: %d\n", err);
 	return err;
@@ -393,11 +397,6 @@ static void omap_aes_dma_cleanup(struct omap_aes_dev *dd)
 {
 	dma_release_channel(dd->dma_lch_out);
 	dma_release_channel(dd->dma_lch_in);
-	dma_unmap_single(dd->dev, dd->dma_addr_out, dd->buflen,
-			 DMA_FROM_DEVICE);
-	dma_unmap_single(dd->dev, dd->dma_addr_in, dd->buflen, DMA_TO_DEVICE);
-	free_pages((unsigned long)dd->buf_out, OMAP_AES_CACHE_SIZE);
-	free_pages((unsigned long)dd->buf_in, OMAP_AES_CACHE_SIZE);
 }
 
 static void sg_copy_buf(void *buf, struct scatterlist *sg,
@@ -414,59 +413,27 @@ static void sg_copy_buf(void *buf, struct scatterlist *sg,
 	scatterwalk_done(&walk, out, 0);
 }
 
-static int sg_copy(struct scatterlist **sg, size_t *offset, void *buf,
-		   size_t buflen, size_t total, int out)
-{
-	unsigned int count, off = 0;
-
-	while (buflen && total) {
-		count = min((*sg)->length - *offset, total);
-		count = min(count, buflen);
-
-		if (!count)
-			return off;
-
-		/*
-		 * buflen and total are AES_BLOCK_SIZE size aligned,
-		 * so count should be also aligned
-		 */
-
-		sg_copy_buf(buf + off, *sg, *offset, count, out);
-
-		off += count;
-		buflen -= count;
-		*offset += count;
-		total -= count;
-
-		if (*offset == (*sg)->length) {
-			*sg = sg_next(*sg);
-			if (*sg)
-				*offset = 0;
-			else
-				total = 0;
-		}
-	}
-
-	return off;
-}
-
 static int omap_aes_crypt_dma(struct crypto_tfm *tfm,
-		struct scatterlist *in_sg, struct scatterlist *out_sg)
+		struct scatterlist *in_sg, struct scatterlist *out_sg,
+		int in_sg_len, int out_sg_len)
 {
 	struct omap_aes_ctx *ctx = crypto_tfm_ctx(tfm);
 	struct omap_aes_dev *dd = ctx->dd;
 	struct dma_async_tx_descriptor *tx_in, *tx_out;
 	struct dma_slave_config cfg;
-	dma_addr_t dma_addr_in = sg_dma_address(in_sg);
-	int ret, length = sg_dma_len(in_sg);
+	int ret;
 
-	pr_debug("len: %d\n", length);
+	if (dd->pio_only) {
+		scatterwalk_start(&dd->in_walk, dd->in_sg);
+		scatterwalk_start(&dd->out_walk, dd->out_sg);
 
-	dd->dma_size = length;
+		/* Enable DATAIN interrupt and let it take
+		   care of the rest */
+		omap_aes_write(dd, AES_REG_IRQ_ENABLE(dd), 0x2);
+		return 0;
+	}
 
-	if (!(dd->flags & FLAGS_FAST))
-		dma_sync_single_for_device(dd->dev, dma_addr_in, length,
-					   DMA_TO_DEVICE);
+	dma_sync_sg_for_device(dd->dev, dd->in_sg, in_sg_len, DMA_TO_DEVICE);
 
 	memset(&cfg, 0, sizeof(cfg));
 
@@ -485,7 +452,7 @@ static int omap_aes_crypt_dma(struct crypto_tfm *tfm,
 		return ret;
 	}
 
-	tx_in = dmaengine_prep_slave_sg(dd->dma_lch_in, in_sg, 1,
+	tx_in = dmaengine_prep_slave_sg(dd->dma_lch_in, in_sg, in_sg_len,
 					DMA_MEM_TO_DEV,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!tx_in) {
@@ -504,7 +471,7 @@ static int omap_aes_crypt_dma(struct crypto_tfm *tfm,
 		return ret;
 	}
 
-	tx_out = dmaengine_prep_slave_sg(dd->dma_lch_out, out_sg, 1,
+	tx_out = dmaengine_prep_slave_sg(dd->dma_lch_out, out_sg, out_sg_len,
 					DMA_DEV_TO_MEM,
 					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!tx_out) {
@@ -522,7 +489,7 @@ static int omap_aes_crypt_dma(struct crypto_tfm *tfm,
 	dma_async_issue_pending(dd->dma_lch_out);
 
 	/* start DMA */
-	dd->pdata->trigger(dd, length);
+	dd->pdata->trigger(dd, dd->total);
 
 	return 0;
 }
@@ -531,93 +498,32 @@ static int omap_aes_crypt_dma_start(struct omap_aes_dev *dd)
 {
 	struct crypto_tfm *tfm = crypto_ablkcipher_tfm(
 					crypto_ablkcipher_reqtfm(dd->req));
-	int err, fast = 0, in, out;
-	size_t count;
-	dma_addr_t addr_in, addr_out;
-	struct scatterlist *in_sg, *out_sg;
-	int len32;
+	int err;
 
 	pr_debug("total: %d\n", dd->total);
 
-	if (sg_is_last(dd->in_sg) && sg_is_last(dd->out_sg)) {
-		/* check for alignment */
-		in = IS_ALIGNED((u32)dd->in_sg->offset, sizeof(u32));
-		out = IS_ALIGNED((u32)dd->out_sg->offset, sizeof(u32));
-
-		fast = in && out;
-	}
-
-	if (fast)  {
-		count = min(dd->total, sg_dma_len(dd->in_sg));
-		count = min(count, sg_dma_len(dd->out_sg));
-
-		if (count != dd->total) {
-			pr_err("request length != buffer length\n");
-			return -EINVAL;
-		}
-
-		pr_debug("fast\n");
-
-		err = dma_map_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
+	if (!dd->pio_only) {
+		err = dma_map_sg(dd->dev, dd->in_sg, dd->in_sg_len,
+				 DMA_TO_DEVICE);
 		if (!err) {
 			dev_err(dd->dev, "dma_map_sg() error\n");
 			return -EINVAL;
 		}
 
-		err = dma_map_sg(dd->dev, dd->out_sg, 1, DMA_FROM_DEVICE);
+		err = dma_map_sg(dd->dev, dd->out_sg, dd->out_sg_len,
+				 DMA_FROM_DEVICE);
 		if (!err) {
 			dev_err(dd->dev, "dma_map_sg() error\n");
-			dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
 			return -EINVAL;
 		}
-
-		addr_in = sg_dma_address(dd->in_sg);
-		addr_out = sg_dma_address(dd->out_sg);
-
-		in_sg = dd->in_sg;
-		out_sg = dd->out_sg;
-
-		dd->flags |= FLAGS_FAST;
-
-	} else {
-		/* use cache buffers */
-		count = sg_copy(&dd->in_sg, &dd->in_offset, dd->buf_in,
-				 dd->buflen, dd->total, 0);
-
-		len32 = DIV_ROUND_UP(count, DMA_MIN) * DMA_MIN;
-
-		/*
-		 * The data going into the AES module has been copied
-		 * to a local buffer and the data coming out will go
-		 * into a local buffer so set up local SG entries for
-		 * both.
-		 */
-		sg_init_table(&dd->in_sgl, 1);
-		dd->in_sgl.offset = dd->in_offset;
-		sg_dma_len(&dd->in_sgl) = len32;
-		sg_dma_address(&dd->in_sgl) = dd->dma_addr_in;
-
-		sg_init_table(&dd->out_sgl, 1);
-		dd->out_sgl.offset = dd->out_offset;
-		sg_dma_len(&dd->out_sgl) = len32;
-		sg_dma_address(&dd->out_sgl) = dd->dma_addr_out;
-
-		in_sg = &dd->in_sgl;
-		out_sg = &dd->out_sgl;
-
-		addr_in = dd->dma_addr_in;
-		addr_out = dd->dma_addr_out;
-
-		dd->flags &= ~FLAGS_FAST;
-
 	}
 
-	dd->total -= count;
-
-	err = omap_aes_crypt_dma(tfm, in_sg, out_sg);
-	if (err) {
-		dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
-		dma_unmap_sg(dd->dev, dd->out_sg, 1, DMA_TO_DEVICE);
+	err = omap_aes_crypt_dma(tfm, dd->in_sg, dd->out_sg, dd->in_sg_len,
+				 dd->out_sg_len);
+	if (err && !dd->pio_only) {
+		dma_unmap_sg(dd->dev, dd->in_sg, dd->in_sg_len, DMA_TO_DEVICE);
+		dma_unmap_sg(dd->dev, dd->out_sg, dd->out_sg_len,
+			     DMA_FROM_DEVICE);
 	}
 
 	return err;
@@ -637,7 +543,6 @@ static void omap_aes_finish_req(struct omap_aes_dev *dd, int err)
 static int omap_aes_crypt_dma_stop(struct omap_aes_dev *dd)
 {
 	int err = 0;
-	size_t count;
 
 	pr_debug("total: %d\n", dd->total);
 
@@ -646,23 +551,49 @@ static int omap_aes_crypt_dma_stop(struct omap_aes_dev *dd)
 	dmaengine_terminate_all(dd->dma_lch_in);
 	dmaengine_terminate_all(dd->dma_lch_out);
 
-	if (dd->flags & FLAGS_FAST) {
-		dma_unmap_sg(dd->dev, dd->out_sg, 1, DMA_FROM_DEVICE);
-		dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
-	} else {
-		dma_sync_single_for_device(dd->dev, dd->dma_addr_out,
-					   dd->dma_size, DMA_FROM_DEVICE);
-
-		/* copy data */
-		count = sg_copy(&dd->out_sg, &dd->out_offset, dd->buf_out,
-				 dd->buflen, dd->dma_size, 1);
-		if (count != dd->dma_size) {
-			err = -EINVAL;
-			pr_err("not all data converted: %u\n", count);
-		}
+	return err;
+}
+
+int omap_aes_check_aligned(struct scatterlist *sg)
+{
+	while (sg) {
+		if (!IS_ALIGNED(sg->offset, 4))
+			return -1;
+		if (!IS_ALIGNED(sg->length, AES_BLOCK_SIZE))
+			return -1;
+		sg = sg_next(sg);
 	}
+	return 0;
+}
 
-	return err;
+int omap_aes_copy_sgs(struct omap_aes_dev *dd)
+{
+	void *buf_in, *buf_out;
+	int pages;
+
+	pages = get_order(dd->total);
+
+	buf_in = (void *)__get_free_pages(GFP_ATOMIC, pages);
+	buf_out = (void *)__get_free_pages(GFP_ATOMIC, pages);
+
+	if (!buf_in || !buf_out) {
+		pr_err("Couldn't allocated pages for unaligned cases.\n");
+		return -1;
+	}
+
+	dd->orig_out = dd->out_sg;
+
+	sg_copy_buf(buf_in, dd->in_sg, 0, dd->total, 0);
+
+	sg_init_table(&dd->in_sgl, 1);
+	sg_set_buf(&dd->in_sgl, buf_in, dd->total);
+	dd->in_sg = &dd->in_sgl;
+
+	sg_init_table(&dd->out_sgl, 1);
+	sg_set_buf(&dd->out_sgl, buf_out, dd->total);
+	dd->out_sg = &dd->out_sgl;
+
+	return 0;
 }
 
 static int omap_aes_handle_queue(struct omap_aes_dev *dd,
@@ -698,11 +629,23 @@ static int omap_aes_handle_queue(struct omap_aes_dev *dd,
 	/* assign new request to device */
 	dd->req = req;
 	dd->total = req->nbytes;
-	dd->in_offset = 0;
+	dd->total_save = req->nbytes;
 	dd->in_sg = req->src;
-	dd->out_offset = 0;
 	dd->out_sg = req->dst;
 
+	if (omap_aes_check_aligned(dd->in_sg) ||
+	    omap_aes_check_aligned(dd->out_sg)) {
+		if (omap_aes_copy_sgs(dd))
+			pr_err("Failed to copy SGs for unaligned cases\n");
+		dd->sgs_copied = 1;
+	} else {
+		dd->sgs_copied = 0;
+	}
+
+	dd->in_sg_len = scatterwalk_bytes_sglen(dd->in_sg, dd->total);
+	dd->out_sg_len = scatterwalk_bytes_sglen(dd->out_sg, dd->total);
+	BUG_ON(dd->in_sg_len < 0 || dd->out_sg_len < 0);
+
 	rctx = ablkcipher_request_ctx(req);
 	ctx = crypto_ablkcipher_ctx(crypto_ablkcipher_reqtfm(req));
 	rctx->mode &= FLAGS_MODE_MASK;
@@ -726,21 +669,32 @@ static int omap_aes_handle_queue(struct omap_aes_dev *dd,
 static void omap_aes_done_task(unsigned long data)
 {
 	struct omap_aes_dev *dd = (struct omap_aes_dev *)data;
-	int err;
-
-	pr_debug("enter\n");
+	void *buf_in, *buf_out;
+	int pages;
+
+	pr_debug("enter done_task\n");
+
+	if (!dd->pio_only) {
+		dma_sync_sg_for_device(dd->dev, dd->out_sg, dd->out_sg_len,
+				       DMA_FROM_DEVICE);
+		dma_unmap_sg(dd->dev, dd->in_sg, dd->in_sg_len, DMA_TO_DEVICE);
+		dma_unmap_sg(dd->dev, dd->out_sg, dd->out_sg_len,
+			     DMA_FROM_DEVICE);
+		omap_aes_crypt_dma_stop(dd);
+	}
 
-	err = omap_aes_crypt_dma_stop(dd);
+	if (dd->sgs_copied) {
+		buf_in = sg_virt(&dd->in_sgl);
+		buf_out = sg_virt(&dd->out_sgl);
 
-	err = dd->err ? : err;
+		sg_copy_buf(buf_out, dd->orig_out, 0, dd->total_save, 1);
 
-	if (dd->total && !err) {
-		err = omap_aes_crypt_dma_start(dd);
-		if (!err)
-			return; /* DMA started. Not fininishing. */
+		pages = get_order(dd->total_save);
+		free_pages((unsigned long)buf_in, pages);
+		free_pages((unsigned long)buf_out, pages);
 	}
 
-	omap_aes_finish_req(dd, err);
+	omap_aes_finish_req(dd, 0);
 	omap_aes_handle_queue(dd, NULL);
 
 	pr_debug("exit\n");
@@ -1002,6 +956,8 @@ static const struct omap_aes_pdata omap_aes_pdata_omap4 = {
 	.data_ofs	= 0x60,
 	.rev_ofs	= 0x80,
 	.mask_ofs	= 0x84,
+	.irq_status_ofs = 0x8c,
+	.irq_enable_ofs = 0x90,
 	.dma_enable_in	= BIT(5),
 	.dma_enable_out	= BIT(6),
 	.major_mask	= 0x0700,
@@ -1010,6 +966,90 @@ static const struct omap_aes_pdata omap_aes_pdata_omap4 = {
 	.minor_shift	= 0,
 };
 
+static irqreturn_t omap_aes_irq(int irq, void *dev_id)
+{
+	struct omap_aes_dev *dd = dev_id;
+	u32 status, i;
+	u32 *src, *dst;
+
+	status = omap_aes_read(dd, AES_REG_IRQ_STATUS(dd));
+	if (status & AES_REG_IRQ_DATA_IN) {
+		omap_aes_write(dd, AES_REG_IRQ_ENABLE(dd), 0x0);
+
+		BUG_ON(!dd->in_sg);
+
+		BUG_ON(_calc_walked(in) > dd->in_sg->length);
+
+		src = sg_virt(dd->in_sg) + _calc_walked(in);
+
+		for (i = 0; i < AES_BLOCK_WORDS; i++) {
+			omap_aes_write(dd, AES_REG_DATA_N(dd, i), *src);
+
+			scatterwalk_advance(&dd->in_walk, 4);
+			if (dd->in_sg->length == _calc_walked(in)) {
+				dd->in_sg = scatterwalk_sg_next(dd->in_sg);
+				if (dd->in_sg) {
+					scatterwalk_start(&dd->in_walk,
+							  dd->in_sg);
+					src = sg_virt(dd->in_sg) +
+					      _calc_walked(in);
+				}
+			} else {
+				src++;
+			}
+		}
+
+		/* Clear IRQ status */
+		status &= ~AES_REG_IRQ_DATA_IN;
+		omap_aes_write(dd, AES_REG_IRQ_STATUS(dd), status);
+
+		/* Enable DATA_OUT interrupt */
+		omap_aes_write(dd, AES_REG_IRQ_ENABLE(dd), 0x4);
+
+	} else if (status & AES_REG_IRQ_DATA_OUT) {
+		omap_aes_write(dd, AES_REG_IRQ_ENABLE(dd), 0x0);
+
+		BUG_ON(!dd->out_sg);
+
+		BUG_ON(_calc_walked(out) > dd->out_sg->length);
+
+		dst = sg_virt(dd->out_sg) + _calc_walked(out);
+
+		for (i = 0; i < AES_BLOCK_WORDS; i++) {
+			*dst = omap_aes_read(dd, AES_REG_DATA_N(dd, i));
+			scatterwalk_advance(&dd->out_walk, 4);
+			if (dd->out_sg->length == _calc_walked(out)) {
+				dd->out_sg = scatterwalk_sg_next(dd->out_sg);
+				if (dd->out_sg) {
+					scatterwalk_start(&dd->out_walk,
+							  dd->out_sg);
+					dst = sg_virt(dd->out_sg) +
+					      _calc_walked(out);
+				}
+			} else {
+				dst++;
+			}
+		}
+
+		dd->total -= AES_BLOCK_SIZE;
+
+		BUG_ON(dd->total < 0);
+
+		/* Clear IRQ status */
+		status &= ~AES_REG_IRQ_DATA_OUT;
+		omap_aes_write(dd, AES_REG_IRQ_STATUS(dd), status);
+
+		if (!dd->total)
+			/* All bytes read! */
+			tasklet_schedule(&dd->done_task);
+		else
+			/* Enable DATA_IN interrupt for next block */
+			omap_aes_write(dd, AES_REG_IRQ_ENABLE(dd), 0x2);
+	}
+
+	return IRQ_HANDLED;
+}
+
 static const struct of_device_id omap_aes_of_match[] = {
 	{
 		.compatible	= "ti,omap2-aes",
@@ -1115,10 +1155,10 @@ static int omap_aes_probe(struct platform_device *pdev)
 	struct omap_aes_dev *dd;
 	struct crypto_alg *algp;
 	struct resource res;
-	int err = -ENOMEM, i, j;
+	int err = -ENOMEM, i, j, irq = -1;
 	u32 reg;
 
-	dd = kzalloc(sizeof(struct omap_aes_dev), GFP_KERNEL);
+	dd = devm_kzalloc(dev, sizeof(struct omap_aes_dev), GFP_KERNEL);
 	if (dd == NULL) {
 		dev_err(dev, "unable to alloc data struct.\n");
 		goto err_data;
@@ -1158,8 +1198,23 @@ static int omap_aes_probe(struct platform_device *pdev)
 	tasklet_init(&dd->queue_task, omap_aes_queue_task, (unsigned long)dd);
 
 	err = omap_aes_dma_init(dd);
-	if (err)
-		goto err_dma;
+	if (err && AES_REG_IRQ_STATUS(dd) && AES_REG_IRQ_ENABLE(dd)) {
+		dd->pio_only = 1;
+
+		irq = platform_get_irq(pdev, 0);
+		if (irq < 0) {
+			dev_err(dev, "can't get IRQ resource\n");
+			goto err_irq;
+		}
+
+		err = devm_request_irq(dev, irq, omap_aes_irq, 0,
+				dev_name(dev), dd);
+		if (err) {
+			dev_err(dev, "Unable to grab omap-aes IRQ\n");
+			goto err_irq;
+		}
+	}
+
 
 	INIT_LIST_HEAD(&dd->list);
 	spin_lock(&list_lock);
@@ -1187,13 +1242,13 @@ err_algs:
 		for (j = dd->pdata->algs_info[i].registered - 1; j >= 0; j--)
 			crypto_unregister_alg(
 					&dd->pdata->algs_info[i].algs_list[j]);
-	omap_aes_dma_cleanup(dd);
-err_dma:
+	if (!dd->pio_only)
+		omap_aes_dma_cleanup(dd);
+err_irq:
 	tasklet_kill(&dd->done_task);
 	tasklet_kill(&dd->queue_task);
 	pm_runtime_disable(dev);
 err_res:
-	kfree(dd);
 	dd = NULL;
 err_data:
 	dev_err(dev, "initialization failed.\n");
@@ -1221,7 +1276,6 @@ static int omap_aes_remove(struct platform_device *pdev)
 	tasklet_kill(&dd->queue_task);
 	omap_aes_dma_cleanup(dd);
 	pm_runtime_disable(dd->dev);
-	kfree(dd);
 	dd = NULL;
 
 	return 0;