Re: [PATCH] media_build: add fixp-arith.h in linux/include/linux

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 15-05-2012 10:16, Gianluca Gennari escreveu:
> This patch:
> http://patchwork.linuxtv.org/patch/10824/
> moved the file fixp-arith.h from drivers/input/ to include/linux/ .
> 
> To make this file available to old kernels, we must include it in the
> media_build package.
> 
> The version included here comes from kernel 3.4-rc7.
> 
> This patch corrects the following build error:
> 
> media_build/v4l/ov534.c:38:30: error: linux/fixp-arith.h: No such file or directory
> media_build/v4l/ov534.c: In function 'sethue':
> media_build/v4l/ov534.c:1000: error: implicit declaration of function 'fixp_sin'
> media_build/v4l/ov534.c:1001: error: implicit declaration of function 'fixp_cos'
> 
> Tested on kernel 2.6.32-41-generic-pae (Ubuntu 10.04).
> 
> Signed-off-by: Gianluca Gennari <gennarone@gmail.com
> ---
>  linux/include/linux/fixp-arith.h |   87 ++++++++++++++++++++++++++++++++++++++

It is not that simple, as make clean will remove it.

I can think on a few possible solutions for it:
	1) just don't compile ov534 on older kernels;
	2) add a backport patch that will dynamically create it;
	3) add linux/include/linux/fixp-arith.h inside the tarball with:
		TARFILES += include/linux/fixp-arith.h

Eventually, you can also tweak with the building system, but it doesn't sound a good
idea to keep this header there as-is for kernels > 3.4, as some changes on this header
can be added there.

>From all above, (3) is the simpler one. I'll apply it.

Regards,
Mauro


>  1 files changed, 87 insertions(+), 0 deletions(-)
>  create mode 100644 linux/include/linux/fixp-arith.h
> 
> diff --git a/linux/include/linux/fixp-arith.h b/linux/include/linux/fixp-arith.h
> new file mode 100644
> index 0000000..3089d73
> --- /dev/null
> +++ b/linux/include/linux/fixp-arith.h
> @@ -0,0 +1,87 @@
> +#ifndef _FIXP_ARITH_H
> +#define _FIXP_ARITH_H
> +
> +/*
> + * Simplistic fixed-point arithmetics.
> + * Hmm, I'm probably duplicating some code :(
> + *
> + * Copyright (c) 2002 Johann Deneux
> + */
> +
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + *
> + * Should you need to contact me, the author, you can do so by
> + * e-mail - mail your message to <johann.deneux@gmail.com>
> + */
> +
> +#include <linux/types.h>
> +
> +/* The type representing fixed-point values */
> +typedef s16 fixp_t;
> +
> +#define FRAC_N 8
> +#define FRAC_MASK ((1<<FRAC_N)-1)
> +
> +/* Not to be used directly. Use fixp_{cos,sin} */
> +static const fixp_t cos_table[46] = {
> +	0x0100,	0x00FF,	0x00FF,	0x00FE,	0x00FD,	0x00FC,	0x00FA,	0x00F8,
> +	0x00F6,	0x00F3,	0x00F0,	0x00ED,	0x00E9,	0x00E6,	0x00E2,	0x00DD,
> +	0x00D9,	0x00D4,	0x00CF,	0x00C9,	0x00C4,	0x00BE,	0x00B8,	0x00B1,
> +	0x00AB,	0x00A4,	0x009D,	0x0096,	0x008F,	0x0087,	0x0080,	0x0078,
> +	0x0070,	0x0068,	0x005F,	0x0057,	0x004F,	0x0046,	0x003D,	0x0035,
> +	0x002C,	0x0023,	0x001A,	0x0011,	0x0008, 0x0000
> +};
> +
> +
> +/* a: 123 -> 123.0 */
> +static inline fixp_t fixp_new(s16 a)
> +{
> +	return a<<FRAC_N;
> +}
> +
> +/* a: 0xFFFF -> -1.0
> +      0x8000 -> 1.0
> +      0x0000 -> 0.0
> +*/
> +static inline fixp_t fixp_new16(s16 a)
> +{
> +	return ((s32)a)>>(16-FRAC_N);
> +}
> +
> +static inline fixp_t fixp_cos(unsigned int degrees)
> +{
> +	int quadrant = (degrees / 90) & 3;
> +	unsigned int i = degrees % 90;
> +
> +	if (quadrant == 1 || quadrant == 3)
> +		i = 90 - i;
> +
> +	i >>= 1;
> +
> +	return (quadrant == 1 || quadrant == 2)? -cos_table[i] : cos_table[i];
> +}
> +
> +static inline fixp_t fixp_sin(unsigned int degrees)
> +{
> +	return -fixp_cos(degrees + 90);
> +}
> +
> +static inline fixp_t fixp_mult(fixp_t a, fixp_t b)
> +{
> +	return ((s32)(a*b))>>FRAC_N;
> +}
> +
> +#endif