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From: Alexander Kochetkov <al.kochet@gmail.com>
To: Dan Williams <dan.j.williams@intel.com>,
	Vinod Koul <vinod.koul@intel.com>,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-rockchip@lists.infradead.org, hhb@rock-chips.com,
	shawn.lin@rock-chips.com, caesar.wang@rock-chips.com,
	sugar.zhang@rock-chips.com, ulysses.huang@rock-chips.com
Cc: Alexander Kochetkov <al.kochet@gmail.com>
Subject: [PATCH 2/2] dmaengine: pl330: don't emit code for one iteration loop
Date: Fri, 14 Apr 2017 17:35:30 +0300	[thread overview]
Message-ID: <1492180531-1780-3-git-send-email-al.kochet@gmail.com> (raw)
In-Reply-To: <1492180531-1780-1-git-send-email-al.kochet@gmail.com>

The patch remove one iteration outer loop in the _loop().
Removing loop saves 4 bytes of MicroCode buffer. This
savings make sense for free-running cyclic transfer
implementation.

    DMALP_0 0
    ...
    DMALPENDA_0 bjmpto_9

Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com>
---
 drivers/dma/pl330.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 56a2377..6126dde 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1268,7 +1268,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 	lpend.bjump = 0;
 	szlpend = _emit_LPEND(1, buf, &lpend);
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		szlp *= 2;
 		szlpend *= 2;
 	}
@@ -1284,7 +1284,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 
 	off = 0;
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		off += _emit_LP(dry_run, &buf[off], 0, lcnt0);
 		ljmp0 = off;
 	}
@@ -1300,7 +1300,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 	lpend.bjump = off - ljmp1;
 	off += _emit_LPEND(dry_run, &buf[off], &lpend);
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		lpend.cond = ALWAYS;
 		lpend.forever = false;
 		lpend.loop = 0;
@@ -1309,7 +1309,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 	}
 
 	*bursts = lcnt1 * cyc;
-	if (lcnt0)
+	if (lcnt0 > 1)
 		*bursts *= lcnt0;
 
 	return off;
-- 
1.7.9.5

WARNING: multiple messages have this Message-ID (diff)
From: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Dan Williams
	<dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Vinod Koul <vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	hhb-TNX95d0MmH7DzftRWevZcw@public.gmane.org,
	shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org,
	caesar.wang-TNX95d0MmH7DzftRWevZcw@public.gmane.org,
	sugar.zhang-TNX95d0MmH7DzftRWevZcw@public.gmane.org,
	ulysses.huang-TNX95d0MmH7DzftRWevZcw@public.gmane.org
Cc: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: [PATCH 2/2] dmaengine: pl330: don't emit code for one iteration loop
Date: Fri, 14 Apr 2017 17:35:30 +0300	[thread overview]
Message-ID: <1492180531-1780-3-git-send-email-al.kochet@gmail.com> (raw)
In-Reply-To: <1492180531-1780-1-git-send-email-al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

The patch remove one iteration outer loop in the _loop().
Removing loop saves 4 bytes of MicroCode buffer. This
savings make sense for free-running cyclic transfer
implementation.

    DMALP_0 0
    ...
    DMALPENDA_0 bjmpto_9

Signed-off-by: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/dma/pl330.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 56a2377..6126dde 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1268,7 +1268,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 	lpend.bjump = 0;
 	szlpend = _emit_LPEND(1, buf, &lpend);
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		szlp *= 2;
 		szlpend *= 2;
 	}
@@ -1284,7 +1284,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 
 	off = 0;
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		off += _emit_LP(dry_run, &buf[off], 0, lcnt0);
 		ljmp0 = off;
 	}
@@ -1300,7 +1300,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 	lpend.bjump = off - ljmp1;
 	off += _emit_LPEND(dry_run, &buf[off], &lpend);
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		lpend.cond = ALWAYS;
 		lpend.forever = false;
 		lpend.loop = 0;
@@ -1309,7 +1309,7 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
 	}
 
 	*bursts = lcnt1 * cyc;
-	if (lcnt0)
+	if (lcnt0 > 1)
 		*bursts *= lcnt0;
 
 	return off;
-- 
1.7.9.5

  parent reply	other threads:[~2017-04-14 14:36 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-14 14:35 [PATCH 0/2] Free running cyclic transfer implementation for pl330 Alexander Kochetkov
2017-04-14 14:35 ` Alexander Kochetkov
2017-04-14 14:35 ` [PATCH 1/2] dmaengine: pl330: make cyclic transfer free runnable Alexander Kochetkov
2017-04-14 14:35   ` Alexander Kochetkov
2017-04-14 18:04   ` Krzysztof Kozlowski
2017-04-14 14:35 ` Alexander Kochetkov [this message]
2017-04-14 14:35   ` [PATCH 2/2] dmaengine: pl330: don't emit code for one iteration loop Alexander Kochetkov
2017-04-18  2:26 ` [PATCH 0/2] Free running cyclic transfer implementation for pl330 sugar
2017-04-26 17:01 ` Alexander Kochetkov

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