From 7561300a7cea56b61fa28b36d40cdfab22af38bd Mon Sep 17 00:00:00 2001
From: Miroslav Sustek <sustmidown@centrum.cz>
Date: Mon, 6 Apr 2009 20:07:04 -0300
Subject: [PATCH] V4L/DVB (11441): cx88-dsp: fixing 64bit math
cx88-dsp: fixing 64bit math on 32bit kernels
Some gcc versions report the missing of __divdi3
[mchehab.redhat.com: CodingStyle fixes]
Signed-off-by: Miroslav Sustek <sustmidown@centrum.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
drivers/media/video/cx88/cx88-dsp.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/media/video/cx88/cx88-dsp.c b/drivers/media/video/cx88/cx88-dsp.c
index a78286e853c3..3e5eaf3fe2a6 100644
--- a/drivers/media/video/cx88/cx88-dsp.c
+++ b/drivers/media/video/cx88/cx88-dsp.c
@@ -22,6 +22,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/jiffies.h>
+#include <asm/div64.h>
#include "cx88.h"
#include "cx88-reg.h"
@@ -100,13 +101,25 @@ static u32 int_goertzel(s16 x[], u32 N, u32 freq)
s32 s_prev2 = 0;
s32 coeff = 2*int_cos(freq);
u32 i;
+
+ u64 tmp;
+ u32 divisor;
+
for (i = 0; i < N; i++) {
s32 s = x[i] + ((s64)coeff*s_prev/32768) - s_prev2;
s_prev2 = s_prev;
s_prev = s;
}
- return (u32)(((s64)s_prev2*s_prev2 + (s64)s_prev*s_prev -
- (s64)coeff*s_prev2*s_prev/32768)/N/N);
+
+ tmp = (s64)s_prev2 * s_prev2 + (s64)s_prev * s_prev -
+ (s64)coeff * s_prev2 * s_prev / 32768;
+
+ /* XXX: N must be low enough so that N*N fits in s32.
+ * Else we need two divisions. */
+ divisor = N * N;
+ do_div(tmp, divisor);
+
+ return (u32) tmp;
}
static u32 freq_magnitude(s16 x[], u32 N, u32 freq)