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Commit 49bb9e6d authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Staging: echo: fix up remaining checkpatch.pl issues 



It's all just minor comment spacing issues.  This patch fixes
up the remaining ones and now the code is checkpatch.pl clean.

Cc: Steve Underwood <steveu@coppice.org>
Cc: David Rowe <david@rowetel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 817bb334

drivers/staging/echo/TODO

+0 −1
Original line number Diff line number Diff line 
TODO:

	- checkpatch.pl cleanups

	- handle bit_operations.h (merge in or make part of common code?)

	- remove proc interface, only use echo.h interface (proc interface is

	  racy and not correct.)

drivers/staging/echo/echo.c

+96 −69
Original line number Diff line number Diff line
@@ -102,7 +102,7 @@ 
   Mark, Pawel, and Pavel.

*/



#include <linux/kernel.h>	/* We're doing kernel work */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/slab.h>
@@ -114,9 +114,6 @@ 
#define DTD_HANGOVER			600	/* 600 samples, or 75ms     */

#define DC_LOG2BETA			3	/* log2() of DC filter Beta */



/*-----------------------------------------------------------------------*\

				   FUNCTIONS

\*-----------------------------------------------------------------------*/



/* adapting coeffs using the traditional stochastic descent (N)LMS algorithm */
@@ -328,7 +325,7 @@ void oslec_snapshot(struct oslec_state *ec) 
}

EXPORT_SYMBOL_GPL(oslec_snapshot);



/* Dual Path Echo Canceller ------------------------------------------------*/

/* Dual Path Echo Canceller */



int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx)

{
@@ -336,9 +333,11 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	int clean_bg;

	int tmp, tmp1;



	/* Input scaling was found be required to prevent problems when tx

	   starts clipping.  Another possible way to handle this would be the

	   filter coefficent scaling. */

	/*

	 * Input scaling was found be required to prevent problems when tx

	 * starts clipping.  Another possible way to handle this would be the

	 * filter coefficent scaling.

	 */



	ec->tx = tx;

	ec->rx = rx;
@@ -346,33 +345,40 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	rx >>= 1;



	/*

	   Filter DC, 3dB point is 160Hz (I think), note 32 bit precision required

	   otherwise values do not track down to 0. Zero at DC, Pole at (1-Beta)

	   only real axis.  Some chip sets (like Si labs) don't need

	   this, but something like a $10 X100P card does.  Any DC really slows

	   down convergence.



	   Note: removes some low frequency from the signal, this reduces

	   the speech quality when listening to samples through headphones

	   but may not be obvious through a telephone handset.



	   Note that the 3dB frequency in radians is approx Beta, e.g. for

	   Beta = 2^(-3) = 0.125, 3dB freq is 0.125 rads = 159Hz.

	 * Filter DC, 3dB point is 160Hz (I think), note 32 bit precision

	 * required otherwise values do not track down to 0. Zero at DC, Pole

	 * at (1-Beta) only real axis.  Some chip sets (like Si labs) don't

	 * need this, but something like a $10 X100P card does.  Any DC really

	 * slows down convergence.

	 *

	 * Note: removes some low frequency from the signal, this reduces the

	 * speech quality when listening to samples through headphones but may

	 * not be obvious through a telephone handset.

	 *

	 * Note that the 3dB frequency in radians is approx Beta, e.g. for Beta

	 * = 2^(-3) = 0.125, 3dB freq is 0.125 rads = 159Hz.

	 */



	if (ec->adaption_mode & ECHO_CAN_USE_RX_HPF) {

		tmp = rx << 15;

#if 1

		/* Make sure the gain of the HPF is 1.0. This can still saturate a little under

		   impulse conditions, and it might roll to 32768 and need clipping on sustained peak

		   level signals. However, the scale of such clipping is small, and the error due to

		   any saturation should not markedly affect the downstream processing. */

		/*

		 * Make sure the gain of the HPF is 1.0. This can still

		 * saturate a little under impulse conditions, and it might

		 * roll to 32768 and need clipping on sustained peak level

		 * signals. However, the scale of such clipping is small, and

		 * the error due to any saturation should not markedly affect

		 * the downstream processing.

		 */

		tmp -= (tmp >> 4);

#endif

		ec->rx_1 += -(ec->rx_1 >> DC_LOG2BETA) + tmp - ec->rx_2;



		/* hard limit filter to prevent clipping.  Note that at this stage

		   rx should be limited to +/- 16383 due to right shift above */

		/*

		 * hard limit filter to prevent clipping.  Note that at this

		 * stage rx should be limited to +/- 16383 due to right shift

		 * above

		 */

		tmp1 = ec->rx_1 >> 15;

		if (tmp1 > 16383)

			tmp1 = 16383;
@@ -407,7 +413,7 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	ec->Lrxacc += abs(rx) - ec->Lrx;

	ec->Lrx = (ec->Lrxacc + (1 << 4)) >> 5;



	/* Foreground filter --------------------------------------------------- */

	/* Foreground filter */



	ec->fir_state.coeffs = ec->fir_taps16[0];

	echo_value = fir16(&ec->fir_state, tx);
@@ -415,14 +421,14 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	ec->Lcleanacc += abs(ec->clean) - ec->Lclean;

	ec->Lclean = (ec->Lcleanacc + (1 << 4)) >> 5;



	/* Background filter --------------------------------------------------- */

	/* Background filter */



	echo_value = fir16(&ec->fir_state_bg, tx);

	clean_bg = rx - echo_value;

	ec->Lclean_bgacc += abs(clean_bg) - ec->Lclean_bg;

	ec->Lclean_bg = (ec->Lclean_bgacc + (1 << 4)) >> 5;



	/* Background Filter adaption ----------------------------------------- */

	/* Background Filter adaption */



	/* Almost always adap bg filter, just simple DT and energy

	   detection to minimise adaption in cases of strong double talk.
@@ -483,7 +489,7 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	if (ec->nonupdate_dwell)

		ec->nonupdate_dwell--;



	/* Transfer logic ------------------------------------------------------ */

	/* Transfer logic */



	/* These conditions are from the dual path paper [1], I messed with

	   them a bit to improve performance. */
@@ -495,7 +501,10 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	    /* (ec->Lclean_bg < 0.125*ec->Ltx) */

	    (8 * ec->Lclean_bg < ec->Ltx)) {

		if (ec->cond_met == 6) {

			/* BG filter has had better results for 6 consecutive samples */

			/*

			 * BG filter has had better results for 6 consecutive

			 * samples

			 */

			ec->adapt = 1;

			memcpy(ec->fir_taps16[0], ec->fir_taps16[1],

				ec->taps * sizeof(int16_t));
@@ -504,25 +513,34 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
	} else

		ec->cond_met = 0;



	/* Non-Linear Processing --------------------------------------------------- */

	/* Non-Linear Processing */



	ec->clean_nlp = ec->clean;

	if (ec->adaption_mode & ECHO_CAN_USE_NLP) {

		/* Non-linear processor - a fancy way to say "zap small signals, to avoid

		   residual echo due to (uLaw/ALaw) non-linearity in the channel.". */

		/*

		 * Non-linear processor - a fancy way to say "zap small

		 * signals, to avoid residual echo due to (uLaw/ALaw)

		 * non-linearity in the channel.".

		 */



		if ((16 * ec->Lclean < ec->Ltx)) {

			/* Our e/c has improved echo by at least 24 dB (each factor of 2 is 6dB,

			   so 2*2*2*2=16 is the same as 6+6+6+6=24dB) */

			/*

			 * Our e/c has improved echo by at least 24 dB (each

			 * factor of 2 is 6dB, so 2*2*2*2=16 is the same as

			 * 6+6+6+6=24dB)

			 */

			if (ec->adaption_mode & ECHO_CAN_USE_CNG) {

				ec->cng_level = ec->Lbgn;



				/* Very elementary comfort noise generation.  Just random

				   numbers rolled off very vaguely Hoth-like.  DR: This

				   noise doesn't sound quite right to me - I suspect there

				   are some overlfow issues in the filtering as it's too

				   "crackly".  TODO: debug this, maybe just play noise at

				   high level or look at spectrum.

				/*

				 * Very elementary comfort noise generation.

				 * Just random numbers rolled off very vaguely

				 * Hoth-like.  DR: This noise doesn't sound

				 * quite right to me - I suspect there are some

				 * overlfow issues in the filtering as it's too

				 * "crackly".

				 * TODO: debug this, maybe just play noise at

				 * high level or look at spectrum.

				 */



				ec->cng_rndnum =
@@ -540,18 +558,22 @@ int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx) 
				if (ec->clean_nlp < -ec->Lbgn)

					ec->clean_nlp = -ec->Lbgn;

			} else {

				/* just mute the residual, doesn't sound very good, used mainly

				   in G168 tests */

				/*

				 * just mute the residual, doesn't sound very

				 * good, used mainly in G168 tests

				 */

				ec->clean_nlp = 0;

			}

		} else {

			/* Background noise estimator.  I tried a few algorithms

			   here without much luck.  This very simple one seems to

			   work best, we just average the level using a slow (1 sec

			   time const) filter if the current level is less than a

			   (experimentally derived) constant.  This means we dont

			   include high level signals like near end speech.  When

			   combined with CNG or especially CLIP seems to work OK.

			/*

			 * Background noise estimator.  I tried a few

			 * algorithms here without much luck.  This very simple

			 * one seems to work best, we just average the level

			 * using a slow (1 sec time const) filter if the

			 * current level is less than a (experimentally

			 * derived) constant.  This means we dont include high

			 * level signals like near end speech.  When combined

			 * with CNG or especially CLIP seems to work OK.

			 */

			if (ec->Lclean < 40) {

				ec->Lbgn_acc += abs(ec->clean) - ec->Lbgn;
@@ -587,12 +609,13 @@ EXPORT_SYMBOL_GPL(oslec_update); 
   It can also help by removing and DC in the tx signal.  DC is bad

   for LMS algorithms.



   This is one of the classic DC removal filters, adjusted to provide sufficient

   bass rolloff to meet the above requirement to protect hybrids from things that

   upset them. The difference between successive samples produces a lousy HPF, and

   then a suitably placed pole flattens things out. The final result is a nicely

   rolled off bass end. The filtering is implemented with extended fractional

   precision, which noise shapes things, giving very clean DC removal.

   This is one of the classic DC removal filters, adjusted to provide

   sufficient bass rolloff to meet the above requirement to protect hybrids

   from things that upset them. The difference between successive samples

   produces a lousy HPF, and then a suitably placed pole flattens things out.

   The final result is a nicely rolled off bass end. The filtering is

   implemented with extended fractional precision, which noise shapes things,

   giving very clean DC removal.

*/



int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx)
@@ -602,10 +625,14 @@ int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx) 
	if (ec->adaption_mode & ECHO_CAN_USE_TX_HPF) {

		tmp = tx << 15;

#if 1

		/* Make sure the gain of the HPF is 1.0. The first can still saturate a little under

		   impulse conditions, and it might roll to 32768 and need clipping on sustained peak

		   level signals. However, the scale of such clipping is small, and the error due to

		   any saturation should not markedly affect the downstream processing. */

		/*

		 * Make sure the gain of the HPF is 1.0. The first can still

		 * saturate a little under impulse conditions, and it might

		 * roll to 32768 and need clipping on sustained peak level

		 * signals. However, the scale of such clipping is small, and

		 * the error due to any saturation should not markedly affect

		 * the downstream processing.

		 */

		tmp -= (tmp >> 4);

#endif

		ec->tx_1 += -(ec->tx_1 >> DC_LOG2BETA) + tmp - ec->tx_2;