The patch number 9449 was added via Manu Abraham <[EMAIL PROTECTED]>
to http://linuxtv.org/hg/v4l-dvb master development tree.
Kernel patches in this development tree may be modified to be backward
compatible with older kernels. Compatibility modifications will be
removed before inclusion into the mainstream Kernel
If anyone has any objections, please let us know by sending a message to:
[EMAIL PROTECTED]
------
From: Reinhard Nissl <[EMAIL PROTECTED]>
Code Simplification: use do_div() instead
Signed-off-by: Reinhard Nissl <[EMAIL PROTECTED]>
Signed-off-by: Manu Abraham <[EMAIL PROTECTED]>
---
linux/drivers/media/dvb/frontends/stb0899_algo.c | 81 +++++++--------
1 file changed, 40 insertions(+), 41 deletions(-)
diff -r fe3cd795b19b -r 3befe7f74867
linux/drivers/media/dvb/frontends/stb0899_algo.c
--- a/linux/drivers/media/dvb/frontends/stb0899_algo.c Mon Jan 21 23:17:48
2008 +0400
+++ b/linux/drivers/media/dvb/frontends/stb0899_algo.c Mon Jan 21 23:43:18
2008 +0400
@@ -23,27 +23,12 @@
#include "stb0899_priv.h"
#include "stb0899_reg.h"
-/*
- * BinaryFloatDiv
- * float division with integer
- */
-static long BinaryFloatDiv(long n1, long n2, int precision)
-{
- int i = 0;
- long result = 0;
-
- while (i <= precision) {
- if (n1 < n2) {
- result *= 2;
- n1 *= 2;
- } else {
- result = result * 2 + 1;
- n1 = (n1 - n2) * 2;
- }
- i++;
- }
-
- return result;
+inline u32 stb0899_do_div(u64 n, u32 d)
+{
+ /* wrap do_div() for ease of use */
+
+ do_div(n, d);
+ return n;
}
/*
@@ -52,15 +37,15 @@ static long BinaryFloatDiv(long n1, long
*/
static u32 stb0899_calc_srate(u32 master_clk, u8 *sfr)
{
- u32 tmp, tmp2, mclk;
-
- mclk = master_clk / 4096L; /* MasterClock * 10 / 2^20 */
- tmp = (((u32) sfr[0] << 12) + ((u32) sfr[1] << 4)) / 16;
-
- tmp *= mclk;
- tmp /= 16;
- tmp2 = ((u32) sfr[2] * mclk) / 256;
- tmp += tmp2;
+ u64 tmp;
+
+ /* srate = (SFR * master_clk) >> 20 */
+
+ /* sfr is of size 20 bit, stored with an offset of 4 bit */
+ tmp = (((u32)sfr[0]) << 16) | (((u32)sfr[1]) << 8) | sfr[2];
+ tmp &= ~0xf;
+ tmp *= master_clk;
+ tmp >>= 24;
return tmp;
}
@@ -72,7 +57,7 @@ u32 stb0899_get_srate(struct stb0899_sta
u32 stb0899_get_srate(struct stb0899_state *state)
{
struct stb0899_internal *internal = &state->internal;
- u8 sfr[4];
+ u8 sfr[3];
stb0899_read_regs(state, STB0899_SFRH, sfr, 3);
@@ -101,16 +86,30 @@ static u32 stb0899_set_srate(struct stb0
*/
// srate_up += (srate_up * 3) / 100;
- tmp = BinaryFloatDiv(srate, master_clk, 20);
-// tmp_up = BinaryFloatDiv(srate_up, master_clk, 20);
-
-// sfr_up[0] = (tmp_up >> 12) & 0xff;
-// sfr_up[1] = (tmp_up >> 4) & 0xff;
-// sfr_up[2] = tmp_up & 0x0f;
-
- sfr[0] = (tmp >> 12) & 0xff;
- sfr[1] = (tmp >> 4) & 0xff;
- sfr[2] = (tmp << 4) & 0xf0;
+ /*
+ * srate = (SFR * master_clk) >> 20
+ * <=>
+ * SFR = srate << 20 / master_clk
+ *
+ * rounded:
+ * SFR = (srate << 21 + master_clk) / (2 * master_clk)
+ *
+ * stored as 20 bit number with an offset of 4 bit:
+ * sfr = SFR << 4;
+ */
+// tmp_up = stb0899_do_div((((u64)srate_up) << 21) + master_clk, 2 *
master_clk);
+// tmp_up <<= 4;
+
+ tmp = stb0899_do_div((((u64)srate) << 21) + master_clk, 2 * master_clk);
+ tmp <<= 4;
+
+// sfr_up[0] = tmp_up >> 16;
+// sfr_up[1] = tmp_up >> 8;
+// sfr_up[2] = tmp_up;
+
+ sfr[0] = tmp >> 16;
+ sfr[1] = tmp >> 8;
+ sfr[2] = tmp;
// stb0899_write_regs(state, STB0899_SFRUPH, sfr_up, 3);
stb0899_write_regs(state, STB0899_SFRH, sfr, 3);
---
Patch is available at:
http://linuxtv.org/hg/v4l-dvb/rev/3befe7f748675c2faed647a47b1d950381732dc2
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