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Subject[PATCH v2 08/12] crypto: atmel-sha: add simple DMA transfers
Date
This patch adds a simple function to perform data transfer with the DMA
controller.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
---
drivers/crypto/atmel-sha.c | 116 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 116 insertions(+)

diff --git a/drivers/crypto/atmel-sha.c b/drivers/crypto/atmel-sha.c
index 58d9ca8ac0f2..a4fc60b67099 100644
--- a/drivers/crypto/atmel-sha.c
+++ b/drivers/crypto/atmel-sha.c
@@ -123,6 +123,9 @@ struct atmel_sha_ctx {
struct atmel_sha_dma {
struct dma_chan *chan;
struct dma_slave_config dma_conf;
+ struct scatterlist *sg;
+ int nents;
+ unsigned int last_sg_length;
};

struct atmel_sha_dev {
@@ -1321,6 +1324,119 @@ static irqreturn_t atmel_sha_irq(int irq, void *dev_id)
}


+/* DMA transfer functions */
+
+static bool atmel_sha_dma_check_aligned(struct atmel_sha_dev *dd,
+ struct scatterlist *sg,
+ size_t len)
+{
+ struct atmel_sha_dma *dma = &dd->dma_lch_in;
+ struct ahash_request *req = dd->req;
+ struct atmel_sha_reqctx *ctx = ahash_request_ctx(req);
+ size_t bs = ctx->block_size;
+ int nents;
+
+ for (nents = 0; sg; sg = sg_next(sg), ++nents) {
+ if (!IS_ALIGNED(sg->offset, sizeof(u32)))
+ return false;
+
+ /*
+ * This is the last sg, the only one that is allowed to
+ * have an unaligned length.
+ */
+ if (len <= sg->length) {
+ dma->nents = nents + 1;
+ dma->last_sg_length = sg->length;
+ sg->length = ALIGN(len, sizeof(u32));
+ return true;
+ }
+
+ /* All other sg lengths MUST be aligned to the block size. */
+ if (!IS_ALIGNED(sg->length, bs))
+ return false;
+
+ len -= sg->length;
+ }
+
+ return false;
+}
+
+static void atmel_sha_dma_callback2(void *data)
+{
+ struct atmel_sha_dev *dd = data;
+ struct atmel_sha_dma *dma = &dd->dma_lch_in;
+ struct scatterlist *sg;
+ int nents;
+
+ dmaengine_terminate_all(dma->chan);
+ dma_unmap_sg(dd->dev, dma->sg, dma->nents, DMA_TO_DEVICE);
+
+ sg = dma->sg;
+ for (nents = 0; nents < dma->nents - 1; ++nents)
+ sg = sg_next(sg);
+ sg->length = dma->last_sg_length;
+
+ dd->is_async = true;
+ (void)atmel_sha_wait_for_data_ready(dd, dd->resume);
+}
+
+static int atmel_sha_dma_start(struct atmel_sha_dev *dd,
+ struct scatterlist *src,
+ size_t len,
+ atmel_sha_fn_t resume)
+{
+ struct atmel_sha_dma *dma = &dd->dma_lch_in;
+ struct dma_slave_config *config = &dma->dma_conf;
+ struct dma_chan *chan = dma->chan;
+ struct dma_async_tx_descriptor *desc;
+ dma_cookie_t cookie;
+ unsigned int sg_len;
+ int err;
+
+ dd->resume = resume;
+
+ /*
+ * dma->nents has already been initialized by
+ * atmel_sha_dma_check_aligned().
+ */
+ dma->sg = src;
+ sg_len = dma_map_sg(dd->dev, dma->sg, dma->nents, DMA_TO_DEVICE);
+ if (!sg_len) {
+ err = -ENOMEM;
+ goto exit;
+ }
+
+ config->src_maxburst = 16;
+ config->dst_maxburst = 16;
+ err = dmaengine_slave_config(chan, config);
+ if (err)
+ goto unmap_sg;
+
+ desc = dmaengine_prep_slave_sg(chan, dma->sg, sg_len, DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc) {
+ err = -ENOMEM;
+ goto unmap_sg;
+ }
+
+ desc->callback = atmel_sha_dma_callback2;
+ desc->callback_param = dd;
+ cookie = dmaengine_submit(desc);
+ err = dma_submit_error(cookie);
+ if (err)
+ goto unmap_sg;
+
+ dma_async_issue_pending(chan);
+
+ return -EINPROGRESS;
+
+unmap_sg:
+ dma_unmap_sg(dd->dev, dma->sg, dma->nents, DMA_TO_DEVICE);
+exit:
+ return atmel_sha_complete(dd, err);
+}
+
+
/* CPU transfer functions */

static int atmel_sha_cpu_transfer(struct atmel_sha_dev *dd)
--
2.7.4
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