[PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[Wang, Yalin]

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@perches.com>
Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com>
---
 sound/usb/6fire/firmware.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c
index 3b02e54..2e39c3f 100644
--- a/sound/usb/6fire/firmware.c
+++ b/sound/usb/6fire/firmware.c
@@ -316,7 +316,7 @@ static int usb6fire_fw_fpga_upload(
 
 	while (c != end) {
 		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
-			buffer[i] = byte_rev_table[(u8) *c];
+			buffer[i] = bitrev8((u8) *c);
 
 		ret = usb6fire_fw_fpga_write(device, buffer, i);
 		if (ret < 0) {
-- 
2.1.1

Re: [PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[Joe Perches]

On Fri, 2014-11-14 at 13:13 +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.
> 
> Signed-off-by: Joe Perches <joe@perches.com>
> Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com>
> ---
[]
> diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c
[]
> @@ -316,7 +316,7 @@ static int usb6fire_fw_fpga_upload(
>  
>  	while (c != end) {
>  		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
> -			buffer[i] = byte_rev_table[(u8) *c];
> +			buffer[i] = bitrev8((u8) *c);

This is not what I submitted.
What I posted did not have a space after (u8)

https://lkml.org/lkml/2014/10/28/1056

If you are going to resubmit or add your own sign-off,
please try to maintain the proper patch that is
submitted and please also use a "From:" line before
the patch itself.

Thanks, Joe

RE: [PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[Wang, Yalin]

> From: Joe Perches [mailto:joe@perches.com]
> > I think the most safe way is change byte_rev_table[] to be satic, So
> > that no driver can access it directly, The build error can remind the
> > developer if they use byte_rev_table[] Directly .
> 
> You can do that with your later patch, but the existing uses _must_ be
> converted first so you don't break the build.
> 
> 
Yeah, I agree with you,
I will add this into my later patch.

Thanks

Re: [PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[Joe Perches]

On Wed, 2014-10-29 at 10:42 +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.
[]
> > 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.
[]
> I think the most safe way is change byte_rev_table[] to be satic,
> So that no driver can access it directly,
> The build error can remind the developer if they use byte_rev_table[]
> Directly .

You can do that with your later patch, but the
existing uses _must_ be converted first so you
don't break the build.

RE: [PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[Wang, Yalin]

> 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@perches.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];
> 
>  sound/usb/6fire/firmware.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c index
> 3b02e54..62c25e7 100644
> --- a/sound/usb/6fire/firmware.c
> +++ b/sound/usb/6fire/firmware.c
> @@ -316,7 +316,7 @@ static int usb6fire_fw_fpga_upload(
> 
>  	while (c != end) {
>  		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
> -			buffer[i] = byte_rev_table[(u8) *c];
> +			buffer[i] = bitrev8((u8)*c);
> 
>  		ret = usb6fire_fw_fpga_write(device, buffer, i);
>  		if (ret < 0) {
> 
I think the most safe way is change byte_rev_table[] to be satic,
So that no driver can access it directly,
The build error can remind the developer if they use byte_rev_table[]
Directly .

Thanks

[PATCH] 6fire: Convert byte_rev_table uses to bitrev8

[Joe Perches]

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@perches.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];

 sound/usb/6fire/firmware.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c
index 3b02e54..62c25e7 100644
--- a/sound/usb/6fire/firmware.c
+++ b/sound/usb/6fire/firmware.c
@@ -316,7 +316,7 @@ static int usb6fire_fw_fpga_upload(
 
 	while (c != end) {
 		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
-			buffer[i] = byte_rev_table[(u8) *c];
+			buffer[i] = bitrev8((u8)*c);
 
 		ret = usb6fire_fw_fpga_write(device, buffer, i);
 		if (ret < 0) {