linux-kernel - [PATCH] carl9170: Convert byte_rev

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Message-ID: <1414531138.10912.12.camel@perches.com>
Date:	Tue, 28 Oct 2014 14:18:58 -0700
From:	Joe Perches <joe@...ches.com>
To:	Christian Lamparter <chunkeey@...glemail.com>
Cc:	"John W. Linville" <linville@...driver.com>,
	"Wang, Yalin" <Yalin.Wang@...ymobile.com>,
	Russell King <linux@....linux.org.uk>, linux-mm@...ck.org,
	Will Deacon <Will.Deacon@....com>,
	Akinobu Mita <akinobu.mita@...il.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-wireless@...r.kernel.org, netdev <netdev@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] carl9170: Convert byte_rev_table uses to bitrev8

Use the inline function instead of directly indexing the array.

This allows some architectures with hardware instructions
for bit reversals to eliminate the array.

Signed-off-by: Joe Perches <joe@...ches.com>
---
On Sun, 2014-10-26 at 23:46 -0700, Joe Perches wrote:
> On Mon, 2014-10-27 at 14:37 +0800, Wang, Yalin wrote:
> > this change add CONFIG_HAVE_ARCH_BITREVERSE config option,
> > so that we can use arm/arm64 rbit instruction to do bitrev operation
> > by hardware.
[]
> > diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
> > index 7ffe03f..ef5b2bb 100644
> > --- a/include/linux/bitrev.h
> > +++ b/include/linux/bitrev.h
> > @@ -3,6 +3,14 @@
> >  
> >  #include <linux/types.h>
> >  
> > +#ifdef CONFIG_HAVE_ARCH_BITREVERSE
> > +#include <asm/bitrev.h>
> > +
> > +#define bitrev32 __arch_bitrev32
> > +#define bitrev16 __arch_bitrev16
> > +#define bitrev8 __arch_bitrev8
> > +
> > +#else
> >  extern u8 const byte_rev_table[256];

 drivers/net/wireless/ath/carl9170/phy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/carl9170/phy.c b/drivers/net/wireless/ath/carl9170/phy.c
index b80b213..dca6df1 100644
--- a/drivers/net/wireless/ath/carl9170/phy.c
+++ b/drivers/net/wireless/ath/carl9170/phy.c
@@ -994,7 +994,7 @@ static int carl9170_init_rf_bank4_pwr(struct ar9170 *ar, bool band5ghz,
 			refsel0 = 0;
 			refsel1 = 1;
 		}
-		chansel = byte_rev_table[chansel];
+		chansel = bitrev8(chansel);
 	} else {
 		if (freq == 2484) {
 			chansel = 10 + (freq - 2274) / 5;
@@ -1002,7 +1002,7 @@ static int carl9170_init_rf_bank4_pwr(struct ar9170 *ar, bool band5ghz,
 		} else
 			chansel = 16 + (freq - 2272) / 5;
 		chansel *= 4;
-		chansel = byte_rev_table[chansel];
+		chansel = bitrev8(chansel);
 	}
 
 	d1 =	chansel;


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