linux-kernel - [PATCH 2/3 v3] dmaengine: pl330: don't emit code for one iteration loop

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Message-Id: <1457607764-30495-3-git-send-email-al.kochet@gmail.com>
Date:	Thu, 10 Mar 2016 14:02:43 +0300
From:	Alexander Kochetkov <al.kochet@...il.com>
To:	Vinod Koul <vinod.koul@...el.com>,
	Dan Williams <dan.j.williams@...el.com>,
	dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:	Caesar Wang <wxt@...k-chips.com>,
	Doug Anderson <dianders@...omium.org>,
	linux-rockchip@...ts.infradead.org,
	Heiko Stuebner <heiko@...ech.de>,
	Alexander Kochetkov <al.kochet@...il.com>
Subject: [PATCH 2/3 v3] dmaengine: pl330: don't emit code for one iteration loop

The patch remove one iteration outer loop in the _loop().
Removing loop saves 4 bytes of MicroCode buffer.

    DMALP_0 0
    ...
    DMALPENDA_0 bjmpto_9

Signed-off-by: Alexander Kochetkov <al.kochet@...il.com>
Reviewed-by: Caesar Wang <wxt@...k-chips.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 4abbc71..b080d70 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1258,7 +1258,7 @@ static inline int _loop(unsigned dry_run, u8 buf[],
 	lpend.bjump = 0;
 	szlpend = _emit_LPEND(1, buf, &lpend);
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		szlp *= 2;
 		szlpend *= 2;
 	}
@@ -1274,7 +1274,7 @@ static inline int _loop(unsigned dry_run, u8 buf[],
 
 	off = 0;
 
-	if (lcnt0) {
+	if (lcnt0 > 1) {
 		off += _emit_LP(dry_run, &buf[off], 0, lcnt0);
 		ljmp0 = off;
 	}
@@ -1290,7 +1290,7 @@ static inline int _loop(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;
@@ -1299,7 +1299,7 @@ static inline int _loop(unsigned dry_run, u8 buf[],
 	}
 
 	*bursts = lcnt1 * cyc;
-	if (lcnt0)
+	if (lcnt0 > 1)
 		*bursts *= lcnt0;
 
 	return off;
-- 
1.7.9.5