linux-kernel - [PATCH V3 09/20] dmaengine/amba-pl08x: Simplify pl08x_ensure

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Date:	Fri, 5 Aug 2011 15:32:34 +0530
From:	Viresh Kumar <viresh.kumar@...com>
To:	<linus.walleij@...aro.org>, <vinod.koul@...el.com>,
	<dan.j.williams@...el.com>
Cc:	<linux-arm-kernel@...ts.infradead.org>, <armando.visconti@...com>,
	<shiraz.hashim@...com>, <vipin.kumar@...com>,
	<rajeev-dlh.kumar@...com>, <deepak.sikri@...com>,
	<vipulkumar.samar@...com>, <amit.virdi@...com>,
	<viresh.kumar@...com>, <pratyush.anand@...com>,
	<bhupesh.sharma@...com>, <viresh.linux@...il.com>,
	<linux-kernel@...r.kernel.org>, <linux@....linux.org.uk>,
	<alim.akhtar@...il.com>
Subject: [PATCH V3 09/20] dmaengine/amba-pl08x: Simplify pl08x_ensure_on()

Simply writing 1 on bit 0 is sufficient instead of reading and clearing bits.
Also as per manual, for bit 3-31 of DMACConfiguration register:
"read undefined, write as 0"

So, we must not rely on values read from this registers bit 3-31.

Signed-off-by: Viresh Kumar <viresh.kumar@...com>
Acked-by: Linus Walleij <linus.walleij@...aro.org>
---
 drivers/dma/amba-pl08x.c |    8 +-------
 1 files changed, 1 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 5dd97f4..d79688d 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -1502,13 +1502,7 @@ bool pl08x_filter_id(struct dma_chan *chan, void *chan_id)
  */
 static void pl08x_ensure_on(struct pl08x_driver_data *pl08x)
 {
-	u32 val;
-
-	val = readl(pl08x->base + PL080_CONFIG);
-	val &= ~(PL080_CONFIG_M2_BE | PL080_CONFIG_M1_BE | PL080_CONFIG_ENABLE);
-	/* We implicitly clear bit 1 and that means little-endian mode */
-	val |= PL080_CONFIG_ENABLE;
-	writel(val, pl08x->base + PL080_CONFIG);
+	writel(PL080_CONFIG_ENABLE, pl08x->base + PL080_CONFIG);
 }
 
 static void pl08x_unmap_buffers(struct pl08x_txd *txd)
-- 
1.7.2.2

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