#include <linux/slab.h>
#include <asm/byteorder.h>
+#include "dvb_math.h"
#include "dvb_frontend.h"
#include "dvb-pll.h"
#include "or51132.h"
/* Demodulator private data */
fe_modulation_t current_modulation;
+ u32 snr; /* Result of last SNR calculation */
/* Tuner private data */
u32 current_frequency;
return 0;
}
-/* log10-1 table at .5 increments from 1 to 100.5 */
-static unsigned int i100x20log10[] = {
- 0, 352, 602, 795, 954, 1088, 1204, 1306, 1397, 1480,
- 1556, 1625, 1690, 1750, 1806, 1858, 1908, 1955, 2000, 2042,
- 2082, 2121, 2158, 2193, 2227, 2260, 2292, 2322, 2352, 2380,
- 2408, 2434, 2460, 2486, 2510, 2534, 2557, 2580, 2602, 2623,
- 2644, 2664, 2684, 2704, 2723, 2742, 2760, 2778, 2795, 2813,
- 2829, 2846, 2862, 2878, 2894, 2909, 2924, 2939, 2954, 2968,
- 2982, 2996, 3010, 3023, 3037, 3050, 3062, 3075, 3088, 3100,
- 3112, 3124, 3136, 3148, 3159, 3170, 3182, 3193, 3204, 3214,
- 3225, 3236, 3246, 3256, 3266, 3276, 3286, 3296, 3306, 3316,
- 3325, 3334, 3344, 3353, 3362, 3371, 3380, 3389, 3397, 3406,
- 3415, 3423, 3432, 3440, 3448, 3456, 3464, 3472, 3480, 3488,
- 3496, 3504, 3511, 3519, 3526, 3534, 3541, 3549, 3556, 3563,
- 3570, 3577, 3584, 3591, 3598, 3605, 3612, 3619, 3625, 3632,
- 3639, 3645, 3652, 3658, 3665, 3671, 3677, 3683, 3690, 3696,
- 3702, 3708, 3714, 3720, 3726, 3732, 3738, 3744, 3750, 3755,
- 3761, 3767, 3772, 3778, 3784, 3789, 3795, 3800, 3806, 3811,
- 3816, 3822, 3827, 3832, 3838, 3843, 3848, 3853, 3858, 3863,
- 3868, 3874, 3879, 3884, 3888, 3893, 3898, 3903, 3908, 3913,
- 3918, 3922, 3927, 3932, 3936, 3941, 3946, 3950, 3955, 3960,
- 3964, 3969, 3973, 3978, 3982, 3986, 3991, 3995, 4000, 4004,
-};
+/* Calculate SNR estimation (scaled by 2^24)
-static unsigned int denom[] = {1,1,100,1000,10000,100000,1000000,10000000,100000000};
+ 8-VSB SNR and QAM equations from Oren datasheets
-static unsigned int i20Log10(unsigned short val)
-{
- unsigned int rntval = 100;
- unsigned int tmp = val;
- unsigned int exp = 1;
+ For 8-VSB:
+ SNR[dB] = 10 * log10(897152044.8282 / MSE^2 ) - K
+
+ Where K = 0 if NTSC rejection filter is OFF; and
+ K = 3 if NTSC rejection filter is ON
+
+ For QAM64:
+ SNR[dB] = 10 * log10(897152044.8282 / MSE^2 )
- while(tmp > 100) {tmp /= 100; exp++;}
+ For QAM256:
+ SNR[dB] = 10 * log10(907832426.314266 / MSE^2 )
- val = (2 * val)/denom[exp];
- if (exp > 1) rntval = 2000*exp;
+ We re-write the snr equation as:
+ SNR * 2^24 = 10*(c - 2*intlog10(MSE))
+ Where for QAM256, c = log10(907832426.314266) * 2^24
+ and for 8-VSB and QAM64, c = log10(897152044.8282) * 2^24 */
- rntval += i100x20log10[val];
- return rntval;
+static u32 calculate_snr(u32 mse, u32 c)
+{
+ if (mse == 0) /* No signal */
+ return 0;
+
+ mse = 2*intlog10(mse);
+ if (mse > c) {
+ /* Negative SNR, which is possible, but realisticly the
+ demod will lose lock before the signal gets this bad. The
+ API only allows for unsigned values, so just return 0 */
+ return 0;
+ }
+ return 10*(c - mse);
}
-static int or51132_read_signal_strength(struct dvb_frontend* fe, u16* strength)
+static int or51132_read_snr(struct dvb_frontend* fe, u16* snr)
{
struct or51132_state* state = fe->demodulator_priv;
- unsigned char rec_buf[2];
- unsigned char snd_buf[2];
- u8 rcvr_stat;
- u16 snr_equ;
- u32 signal_strength;
- int usK;
+ u8 rec_buf[2];
+ u8 snd_buf[2];
+ u32 noise;
+ u32 c;
+ u32 usK;
+ /* Register is same for VSB or QAM firmware */
snd_buf[0]=0x04;
snd_buf[1]=0x02; /* SNR after Equalizer */
msleep(30); /* 30ms */
if (i2c_writebytes(state,state->config->demod_address,snd_buf,2)) {
- printk(KERN_WARNING "or51132: read_status write error\n");
- return -1;
+ printk(KERN_WARNING "or51132: snr write error\n");
+ return -EREMOTEIO;
}
msleep(30); /* 30ms */
if (i2c_readbytes(state,state->config->demod_address,rec_buf,2)) {
- printk(KERN_WARNING "or51132: read_status read error\n");
- return -1;
+ printk(KERN_WARNING "or51132: snr read error\n");
+ return -EREMOTEIO;
}
- snr_equ = rec_buf[0] | (rec_buf[1] << 8);
- dprintk("read_signal_strength snr_equ %x %x (%i)\n",rec_buf[0],rec_buf[1],snr_equ);
+ noise = rec_buf[0] | (rec_buf[1] << 8);
+ dprintk("read_snr noise %x %x (%i)\n",rec_buf[0],rec_buf[1],noise);
- /* Receiver Status */
+ /* Read status, contains modulation type for QAM_AUTO and
+ NTSC filter for VSB */
snd_buf[0]=0x04;
- snd_buf[1]=0x00;
+ snd_buf[1]=0x00; /* Status register */
msleep(30); /* 30ms */
if (i2c_writebytes(state,state->config->demod_address,snd_buf,2)) {
- printk(KERN_WARNING "or51132: read_signal_strength read_status write error\n");
- return -1;
+ printk(KERN_WARNING "or51132: status write error\n");
+ return -EREMOTEIO;
}
msleep(30); /* 30ms */
if (i2c_readbytes(state,state->config->demod_address,rec_buf,2)) {
- printk(KERN_WARNING "or51132: read_signal_strength read_status read error\n");
- return -1;
+ printk(KERN_WARNING "or51132: status read error\n");
+ return -EREMOTEIO;
}
- dprintk("read_signal_strength read_status %x %x\n",rec_buf[0],rec_buf[1]);
- rcvr_stat = rec_buf[1];
- usK = (rcvr_stat & 0x10) ? 3 : 0;
- /* The value reported back from the frontend will be FFFF=100% 0000=0% */
- signal_strength = (((8952 - i20Log10(snr_equ) - usK*100)/3+5)*65535)/1000;
- if (signal_strength > 0xffff)
- *strength = 0xffff;
- else
- *strength = signal_strength;
- dprintk("read_signal_strength %i\n",*strength);
+ usK = 0;
+ switch (rec_buf[0]) {
+ case 0x06:
+ usK = (rec_buf[1] & 0x10) ? 0x03000000 : 0;
+ /* Fall through to QAM64 case */
+ case 0x43:
+ c = 150204167;
+ break;
+ case 0x45:
+ c = 150290396;
+ break;
+ default:
+ printk(KERN_ERR "or51132: unknown status 0x%02x\n", rec_buf[0]);
+ return -EREMOTEIO;
+ }
+ dprintk("%s: modulation %02x, NTSC rej O%s\n", __FUNCTION__,
+ rec_buf[0], rec_buf[1]&0x10?"n":"ff");
+
+ /* Calculate SNR using noise, c, and NTSC rejection correction */
+ state->snr = calculate_snr(noise, c) - usK;
+ *snr = (state->snr) >> 16;
+
+ dprintk("%s: noise = 0x%08x, snr = %d.%02d dB\n", __FUNCTION__, noise,
+ state->snr >> 24, (((state->snr>>8) & 0xffff) * 100) >> 16);
return 0;
}
-static int or51132_read_snr(struct dvb_frontend* fe, u16* snr)
+static int or51132_read_signal_strength(struct dvb_frontend* fe, u16* strength)
{
- struct or51132_state* state = fe->demodulator_priv;
- unsigned char rec_buf[2];
- unsigned char snd_buf[2];
- u16 snr_equ;
-
- snd_buf[0]=0x04;
- snd_buf[1]=0x02; /* SNR after Equalizer */
- msleep(30); /* 30ms */
- if (i2c_writebytes(state,state->config->demod_address,snd_buf,2)) {
- printk(KERN_WARNING "or51132: read_snr write error\n");
- return -1;
- }
- msleep(30); /* 30ms */
- if (i2c_readbytes(state,state->config->demod_address,rec_buf,2)) {
- printk(KERN_WARNING "or51132: read_snr dvr read error\n");
- return -1;
- }
- snr_equ = rec_buf[0] | (rec_buf[1] << 8);
- dprintk("read_snr snr_equ %x %x (%i)\n",rec_buf[0],rec_buf[1],snr_equ);
+ /* Calculate Strength from SNR up to 35dB */
+ /* Even though the SNR can go higher than 35dB, there is some comfort */
+ /* factor in having a range of strong signals that can show at 100% */
+ struct or51132_state* state = (struct or51132_state*) fe->demodulator_priv;
+ u16 snr;
+ int ret;
- *snr = 0xFFFF - snr_equ;
- dprintk("read_snr %i\n",*snr);
+ ret = fe->ops.read_snr(fe, &snr);
+ if (ret != 0)
+ return ret;
+ /* Rather than use the 8.8 value snr, use state->snr which is 8.24 */
+ /* scale the range 0 - 35*2^24 into 0 - 65535 */
+ if (state->snr >= 8960 * 0x10000)
+ *strength = 0xffff;
+ else
+ *strength = state->snr / 8960;
return 0;
}
git://git.onelab.eu / linux-2.6.git / blobdiff