All of lore.kernel.org
 help / color / mirror / Atom feed
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 v2 3/3] crypto: caam/jr - Remove extra memory barrier during job ring enqueue
Date: Fri, 15 Mar 2019 11:25:25 +0000	[thread overview]
Message-ID: <20190315112238.24337-4-vakul.garg@nxp.com> (raw)
In-Reply-To: <20190315112238.24337-1-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 e95f82778fa1..1de2562d0982 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


  parent reply	other threads:[~2019-03-15 11:25 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-15 11:25 [PATCH v2 0/3] CAAM job ring driver cleanups Vakul Garg
2019-03-15 11:25 ` [PATCH v2 1/3] crypto: caam/jr - Remove spinlock for output job ring Vakul Garg
2019-03-21 16:42   ` Horia Geanta
2019-03-15 11:25 ` [PATCH v2 2/3] crypto: caam/jr - Removed redundant vars from job ring private data Vakul Garg
2019-03-21 15:34   ` Horia Geanta
2019-03-15 11:25 ` Vakul Garg [this message]
2019-03-21 11:45   ` [PATCH v2 3/3] crypto: caam/jr - Remove extra memory barrier during job ring enqueue Horia Geanta

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190315112238.24337-4-vakul.garg@nxp.com \
    --to=vakul.garg@nxp.com \
    --cc=aymen.sghaier@nxp.com \
    --cc=herbert@gondor.apana.org.au \
    --cc=horia.geanta@nxp.com \
    --cc=linux-crypto@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.