2014-10-28 21:19:04

by Joe Perches

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 <[email protected]>
---
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;

2014-11-14 05:37:42

by Wang, Yalin

Subject: RE: [PATCH] carl9170: Convert byte_rev_table uses to bitrev8

> From: Joe Perches [mailto:[email protected]]
> Sent: Friday, November 14, 2014 1:33 PM
> To: Wang, Yalin
> Cc: '[email protected]'; '[email protected]'; 'linux-
> [email protected]'; '[email protected]'; 'linux-
> [email protected]'
> Subject: Re: [PATCH] carl9170: Convert byte_rev_table uses to bitrev8
>
> On Fri, 2014-11-14 at 13:16 +0800, Wang, Yalin wrote:
> > Use the inline function instead of directly indexing the array.
> >
> > This allows some architectures with hardware instructions for bit
> > reversals to eliminate the array.
>
> This one is already in -next
>
> commit 7a1283d8f5298437a454ec477384dcd9f9f88bac
> Author: Joe Perches <[email protected]>
> Date: Tue Oct 28 14:18:58 2014 -0700
>
> 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 <[email protected]>
> Signed-off-by: John W. Linville <[email protected]>
>
Got it ,
So I need wait for your another patch to be accepted.

Thanks!