crypto: omap-sham - error handling improved

Introduces DMA error handling.

DMA error is returned as a result code of the hash request.
Clients needs to handle error codes and may repeat hash calculation attempt.

Also in the case of DMA error, SHAM module is set to be re-initialized again.
It significantly improves stability against possible HW failures.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/omap-sham.c

@@ -83,6 +83,7 @@
 #define FLAGS_INIT		0x0100
 #define FLAGS_CPU		0x0200
 #define FLAGS_HMAC		0x0400
+#define FLAGS_ERROR		0x0800
 
 /* 3rd byte */
 #define FLAGS_BUSY		16
@@ -137,6 +138,7 @@ struct omap_sham_dev {
 	int			irq;
 	struct clk		*iclk;
 	spinlock_t		lock;
+	int			err;
 	int			dma;
 	int			dma_lch;
 	struct tasklet_struct	done_task;
@@ -234,10 +236,12 @@ static int omap_sham_write_ctrl(struct omap_sham_dev *dd, size_t length,
 				SHA_REG_MASK_SOFTRESET, SHA_REG_MASK_SOFTRESET);
 
 			if (omap_sham_wait(dd, SHA_REG_SYSSTATUS,
-						SHA_REG_SYSSTATUS_RESETDONE))
+						SHA_REG_SYSSTATUS_RESETDONE)) {
+				clk_disable(dd->iclk);
 				return -ETIMEDOUT;
-
+			}
 			dd->flags |= FLAGS_INIT;
+			dd->err = 0;
 		}
 	} else {
 		omap_sham_write(dd, SHA_REG_DIGCNT, ctx->digcnt);
@@ -279,11 +283,12 @@ static int omap_sham_xmit_cpu(struct omap_sham_dev *dd, const u8 *buf,
 	if (err)
 		return err;
 
+	/* should be non-zero before next lines to disable clocks later */
+	ctx->digcnt += length;
+
 	if (omap_sham_wait(dd, SHA_REG_CTRL, SHA_REG_CTRL_INPUT_READY))
 		return -ETIMEDOUT;
 
-	ctx->digcnt += length;
-
 	if (final)
 		ctx->flags |= FLAGS_FINAL; /* catch last interrupt */
 
@@ -303,7 +308,6 @@ static int omap_sham_xmit_dma(struct omap_sham_dev *dd, dma_addr_t dma_addr,
 
 	dev_dbg(dd->dev, "xmit_dma: digcnt: %d, length: %d, final: %d\n",
 						ctx->digcnt, length, final);
-
 	/* flush cache entries related to our page */
 	if (dma_addr == ctx->dma_addr)
 		dma_sync_single_for_device(dd->dev, dma_addr, length,
@@ -411,6 +415,7 @@ static int omap_sham_update_dma_fast(struct omap_sham_dev *dd)
 {
 	struct omap_sham_reqctx *ctx = ahash_request_ctx(dd->req);
 	unsigned int length;
+	int err;
 
 	ctx->flags |= FLAGS_FAST;
 
@@ -424,7 +429,11 @@ static int omap_sham_update_dma_fast(struct omap_sham_dev *dd)
 
 	ctx->total -= length;
 
-	return omap_sham_xmit_dma(dd, sg_dma_address(ctx->sg), length, 1);
+	err = omap_sham_xmit_dma(dd, sg_dma_address(ctx->sg), length, 1);
+	if (err != -EINPROGRESS)
+		dma_unmap_sg(dd->dev, ctx->sg, 1, DMA_TO_DEVICE);
+
+	return err;
 }
 
 static int omap_sham_update_cpu(struct omap_sham_dev *dd)
@@ -580,9 +589,6 @@ static int omap_sham_final_req(struct omap_sham_dev *dd)
 
 	ctx->bufcnt = 0;
 
-	if (err != -EINPROGRESS)
-		omap_sham_cleanup(req);
-
 	dev_dbg(dd->dev, "final_req: err: %d\n", err);
 
 	return err;
@@ -616,9 +622,11 @@ static void omap_sham_finish_req(struct ahash_request *req, int err)
 		omap_sham_copy_hash(ctx->dd->req, 1);
 		if (ctx->flags & FLAGS_HMAC)
 			err = omap_sham_finish_req_hmac(req);
+	} else {
+		ctx->flags |= FLAGS_ERROR;
 	}
 
-	if (ctx->flags & FLAGS_FINAL)
+	if ((ctx->flags & FLAGS_FINAL) || err)
 		omap_sham_cleanup(req);
 
 	clear_bit(FLAGS_BUSY, &ctx->dd->flags);
@@ -776,12 +784,14 @@ static int omap_sham_final(struct ahash_request *req)
 
 	ctx->flags |= FLAGS_FINUP;
 
-	/* OMAP HW accel works only with buffers >= 9 */
-	/* HMAC is always >= 9 because of ipad */
-	if ((ctx->digcnt + ctx->bufcnt) < 9)
-		err = omap_sham_final_shash(req);
-	else if (ctx->bufcnt)
-		return omap_sham_enqueue(req, OP_FINAL);
+	if (!(ctx->flags & FLAGS_ERROR)) {
+		/* OMAP HW accel works only with buffers >= 9 */
+		/* HMAC is always >= 9 because of ipad */
+		if ((ctx->digcnt + ctx->bufcnt) < 9)
+			err = omap_sham_final_shash(req);
+		else if (ctx->bufcnt)
+			return omap_sham_enqueue(req, OP_FINAL);
+	}
 
 	omap_sham_cleanup(req);
 
@@ -851,6 +861,8 @@ static int omap_sham_cra_init_alg(struct crypto_tfm *tfm, const char *alg_base)
 	struct omap_sham_ctx *tctx = crypto_tfm_ctx(tfm);
 	const char *alg_name = crypto_tfm_alg_name(tfm);
 
+	pr_info("enter\n");
+
 	/* Allocate a fallback and abort if it failed. */
 	tctx->fallback = crypto_alloc_shash(alg_name, 0,
 					    CRYPTO_ALG_NEED_FALLBACK);
@@ -1008,7 +1020,7 @@ static void omap_sham_done_task(unsigned long data)
 	struct omap_sham_dev *dd = (struct omap_sham_dev *)data;
 	struct ahash_request *req = dd->req;
 	struct omap_sham_reqctx *ctx = ahash_request_ctx(req);
-	int ready = 1;
+	int ready = 0, err = 0;
 
 	if (ctx->flags & FLAGS_OUTPUT_READY) {
 		ctx->flags &= ~FLAGS_OUTPUT_READY;
@@ -1018,13 +1030,16 @@ static void omap_sham_done_task(unsigned long data)
 	if (dd->flags & FLAGS_DMA_ACTIVE) {
 		dd->flags &= ~FLAGS_DMA_ACTIVE;
 		omap_sham_update_dma_stop(dd);
-		omap_sham_update_dma_slow(dd);
+		if (!dd->err)
+			err = omap_sham_update_dma_slow(dd);
 	}
 
-	if (ready && !(dd->flags & FLAGS_DMA_ACTIVE)) {
-		dev_dbg(dd->dev, "update done\n");
+	err = dd->err ? : err;
+
+	if (err != -EINPROGRESS && (ready || err)) {
+		dev_dbg(dd->dev, "update done: err: %d\n", err);
 		/* finish curent request */
-		omap_sham_finish_req(req, 0);
+		omap_sham_finish_req(req, err);
 		/* start new request */
 		omap_sham_handle_queue(dd);
 	}
@@ -1056,6 +1071,7 @@ static irqreturn_t omap_sham_irq(int irq, void *dev_id)
 	omap_sham_read(dd, SHA_REG_CTRL);
 
 	ctx->flags |= FLAGS_OUTPUT_READY;
+	dd->err = 0;
 	tasklet_schedule(&dd->done_task);
 
 	return IRQ_HANDLED;
@@ -1065,8 +1081,13 @@ static void omap_sham_dma_callback(int lch, u16 ch_status, void *data)
 {
 	struct omap_sham_dev *dd = data;
 
-	if (likely(lch == dd->dma_lch))
-		tasklet_schedule(&dd->done_task);
+	if (ch_status != OMAP_DMA_BLOCK_IRQ) {
+		pr_err("omap-sham DMA error status: 0x%hx\n", ch_status);
+		dd->err = -EIO;
+		dd->flags &= ~FLAGS_INIT; /* request to re-initialize */
+	}
+
+	tasklet_schedule(&dd->done_task);
 }
 
 static int omap_sham_dma_init(struct omap_sham_dev *dd)