crypto: caam/qi - optimize frame queue cleanup

Add reference counter incremented for each frame enqueued in CAAM
and replace unconditional sleep in empty_caam_fq() with polling the
reference counter.

When CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y boot time on LS1043A
platform with this optimization decreases from ~1100s to ~11s.
Signed-off-by: Valentin Ciocoi Radulescu <valentin.ciocoi@nxp.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/qi.c

@@ -4,7 +4,7 @@
  * Queue Interface backend functionality
  *
  * Copyright 2013-2016 Freescale Semiconductor, Inc.
- * Copyright 2016-2017, 2019 NXP
+ * Copyright 2016-2017, 2019-2020 NXP
  */
 
 #include <linux/cpumask.h>
@@ -124,8 +124,10 @@ int caam_qi_enqueue(struct device *qidev, struct caam_drv_req *req)
 
 	do {
 		ret = qman_enqueue(req->drv_ctx->req_fq, &fd);
-		if (likely(!ret))
+		if (likely(!ret)) {
+			refcount_inc(&req->drv_ctx->refcnt);
 			return 0;
+		}
 
 		if (ret != -EBUSY)
 			break;
@@ -148,11 +150,6 @@ static void caam_fq_ern_cb(struct qman_portal *qm, struct qman_fq *fq,
 
 	fd = &msg->ern.fd;
 
-	if (qm_fd_get_format(fd) != qm_fd_compound) {
-		dev_err(qidev, "Non-compound FD from CAAM\n");
-		return;
-	}
-
 	drv_req = caam_iova_to_virt(priv->domain, qm_fd_addr_get64(fd));
 	if (!drv_req) {
 		dev_err(qidev,
@@ -160,6 +157,13 @@ static void caam_fq_ern_cb(struct qman_portal *qm, struct qman_fq *fq,
 		return;
 	}
 
+	refcount_dec(&drv_req->drv_ctx->refcnt);
+
+	if (qm_fd_get_format(fd) != qm_fd_compound) {
+		dev_err(qidev, "Non-compound FD from CAAM\n");
+		return;
+	}
+
 	dma_unmap_single(drv_req->drv_ctx->qidev, qm_fd_addr(fd),
 			 sizeof(drv_req->fd_sgt), DMA_BIDIRECTIONAL);
 
@@ -287,9 +291,10 @@ static int kill_fq(struct device *qidev, struct qman_fq *fq)
 	return ret;
 }
 
-static int empty_caam_fq(struct qman_fq *fq)
+static int empty_caam_fq(struct qman_fq *fq, struct caam_drv_ctx *drv_ctx)
 {
 	int ret;
+	int retries = 10;
 	struct qm_mcr_queryfq_np np;
 
 	/* Wait till the older CAAM FQ get empty */
@@ -304,11 +309,18 @@ static int empty_caam_fq(struct qman_fq *fq)
 		msleep(20);
 	} while (1);
 
-	/*
-	 * Give extra time for pending jobs from this FQ in holding tanks
-	 * to get processed
-	 */
-	msleep(20);
+	/* Wait until pending jobs from this FQ are processed by CAAM */
+	do {
+		if (refcount_read(&drv_ctx->refcnt) == 1)
+			break;
+
+		msleep(20);
+	} while (--retries);
+
+	if (!retries)
+		dev_warn_once(drv_ctx->qidev, "%d frames from FQID %u still pending in CAAM\n",
+			      refcount_read(&drv_ctx->refcnt), fq->fqid);
+
 	return 0;
 }
 
@@ -340,7 +352,7 @@ int caam_drv_ctx_update(struct caam_drv_ctx *drv_ctx, u32 *sh_desc)
 	drv_ctx->req_fq = new_fq;
 
 	/* Empty and remove the older FQ */
-	ret = empty_caam_fq(old_fq);
+	ret = empty_caam_fq(old_fq, drv_ctx);
 	if (ret) {
 		dev_err(qidev, "Old CAAM FQ empty failed: %d\n", ret);
 
@@ -453,6 +465,9 @@ struct caam_drv_ctx *caam_drv_ctx_init(struct device *qidev,
 		return ERR_PTR(-ENOMEM);
 	}
 
+	/* init reference counter used to track references to request FQ */
+	refcount_set(&drv_ctx->refcnt, 1);
+
 	drv_ctx->qidev = qidev;
 	return drv_ctx;
 }
@@ -571,6 +586,16 @@ static enum qman_cb_dqrr_result caam_rsp_fq_dqrr_cb(struct qman_portal *p,
 		return qman_cb_dqrr_stop;
 
 	fd = &dqrr->fd;
+
+	drv_req = caam_iova_to_virt(priv->domain, qm_fd_addr_get64(fd));
+	if (unlikely(!drv_req)) {
+		dev_err(qidev,
+			"Can't find original request for caam response\n");
+		return qman_cb_dqrr_consume;
+	}
+
+	refcount_dec(&drv_req->drv_ctx->refcnt);
+
 	status = be32_to_cpu(fd->status);
 	if (unlikely(status)) {
 		u32 ssrc = status & JRSTA_SSRC_MASK;
@@ -588,13 +613,6 @@ static enum qman_cb_dqrr_result caam_rsp_fq_dqrr_cb(struct qman_portal *p,
 		return qman_cb_dqrr_consume;
 	}
 
-	drv_req = caam_iova_to_virt(priv->domain, qm_fd_addr_get64(fd));
-	if (unlikely(!drv_req)) {
-		dev_err(qidev,
-			"Can't find original request for caam response\n");
-		return qman_cb_dqrr_consume;
-	}
-
 	dma_unmap_single(drv_req->drv_ctx->qidev, qm_fd_addr(fd),
 			 sizeof(drv_req->fd_sgt), DMA_BIDIRECTIONAL);
 

drivers/crypto/caam/qi.h

@@ -3,7 +3,7 @@
  * Public definitions for the CAAM/QI (Queue Interface) backend.
  *
  * Copyright 2013-2016 Freescale Semiconductor, Inc.
- * Copyright 2016-2017 NXP
+ * Copyright 2016-2017, 2020 NXP
  */
 
 #ifndef __QI_H__
@@ -52,6 +52,7 @@ enum optype {
  * @context_a: shared descriptor dma address
  * @req_fq: to-CAAM request frame queue
  * @rsp_fq: from-CAAM response frame queue
+ * @refcnt: reference counter incremented for each frame enqueued in to-CAAM FQ
  * @cpu: cpu on which to receive CAAM response
  * @op_type: operation type
  * @qidev: device pointer for CAAM/QI backend
@@ -62,6 +63,7 @@ struct caam_drv_ctx {
 	dma_addr_t context_a;
 	struct qman_fq *req_fq;
 	struct qman_fq *rsp_fq;
+	refcount_t refcnt;
 	int cpu;
 	enum optype op_type;
 	struct device *qidev;