From: Vakul Garg <vakul.garg@nxp.com>
To: "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"herbert@gondor.apana.org.au" <herbert@gondor.apana.org.au>
Cc: Horia Geanta <horia.geanta@nxp.com>,
Aymen Sghaier <aymen.sghaier@nxp.com>,
Vakul Garg <vakul.garg@nxp.com>
Subject: [PATCH 3/3] crypto: caam/jr - Remove extra memory barrier during job ring enqueue
Date: Fri, 15 Mar 2019 04:05:25 +0000 [thread overview]
Message-ID: <20190315040239.24705-4-vakul.garg@nxp.com> (raw)
In-Reply-To: <20190315040239.24705-1-vakul.garg@nxp.com>
In caam_jr_enqueue(), a write barrier is needed to order stores to job
ring slot before declaring addition of new job into input job ring.
The register write is done using wr_reg32() which internally uses
iowrite32() for write operation. The api iowrite32() issues a write
barrier before issuing write operation. Therefore, the wmb() preceding
wr_reg32() can be safely removed.
Signed-off-by: Vakul Garg <vakul.garg@nxp.com>
---
drivers/crypto/caam/jr.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/crypto/caam/jr.c b/drivers/crypto/caam/jr.c
index 02f02fa996da..3bd28386eb07 100644
--- a/drivers/crypto/caam/jr.c
+++ b/drivers/crypto/caam/jr.c
@@ -371,9 +371,11 @@ int caam_jr_enqueue(struct device *dev, u32 *desc,
/*
* Ensure that all job information has been written before
- * notifying CAAM that a new job was added to the input ring.
+ * notifying CAAM that a new job was added to the input ring
+ * using a memory barrier. The wr_reg32() uses api iowrite32()
+ * to do the register write. iowrite32() issues a memory barrier
+ * before the write operation.
*/
- wmb();
wr_reg32(&jrp->rregs->inpring_jobadd, 1);
--
2.13.6
prev parent reply other threads:[~2019-03-15 4:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-15 4:05 [PATCH 0/3] CAAM job ring driver cleanups Vakul Garg
2019-03-15 4:05 ` [PATCH 1/3] crypto: caam/jr - Remove spinlock for output job ring Vakul Garg
2019-03-15 8:08 ` Chris Spencer
2019-03-15 4:05 ` [PATCH 2/3] crypto: caam/jr - Remove redundant vars from job ring private data Vakul Garg
2019-03-15 4:05 ` Vakul Garg [this message]
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