[PATCH] ASoC: rsnd: Calculate DALIGN inversion at run-time

[PATCH] ASoC: rsnd: Calculate DALIGN inversion at run-time

[Geert Uytterhoeven]

There is no need to store the inverted DALIGN values in the table, as
they can easily be calculated at run-time.  This also protects against
the introduction of inconsistencies between normal and inverted values
by a future table modification.

Reorder the two subexpressions in the AND check, to perform the least
expensive check first.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Compile-tested only.

Interestingly, this decreases code size on arm64, but increases on arm32
(both gcc version 7.4.0 (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04.1)).

arm32:

       text	   data	    bss	    dec	    hex	filename
      16186	    276	     84	  16546	   40a2	sound/soc/sh/rcar/core.o.orig
      16194	    276	     84	  16554	   40aa	sound/soc/sh/rcar/core.o

arm64:

       text	   data	    bss	    dec	    hex	filename
      17426	    392	    104	  17922	   4602	sound/soc/sh/rcar/core.o.orig
      17414	    392	    104	  17910	   45f6	sound/soc/sh/rcar/core.o
---
 sound/soc/sh/rcar/core.c | 31 +++++++++++++------------------
 1 file changed, 13 insertions(+), 18 deletions(-)

diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index 399dc6e9bde5b042..d20f03dfdee66643 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -376,20 +376,15 @@ u32 rsnd_get_adinr_bit(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
  */
 u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
 {
-	static const u32 dalign_values[8][2] = {
-		{0x76543210, 0x67452301},
-		{0x00000032, 0x00000023},
-		{0x00007654, 0x00006745},
-		{0x00000076, 0x00000067},
-		{0xfedcba98, 0xefcdab89},
-		{0x000000ba, 0x000000ab},
-		{0x0000fedc, 0x0000efcd},
-		{0x000000fe, 0x000000ef},
+	static const u32 dalign_values[8] = {
+		0x76543210, 0x00000032, 0x00007654, 0x00000076,
+		0xfedcba98, 0x000000ba, 0x0000fedc, 0x000000fe,
 	};
-	int id = 0, inv;
+	int id = 0;
 	struct rsnd_mod *ssiu = rsnd_io_to_mod_ssiu(io);
 	struct rsnd_mod *target;
 	struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
+	u32 dalign;
 
 	/*
 	 * *Hardware* L/R and *Software* L/R are inverted for 16bit data.
@@ -425,15 +420,15 @@ u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
 	if (mod == ssiu)
 		id = rsnd_mod_id_sub(mod);
 
-	/* Non target mod or non 16bit needs normal DALIGN */
-	if ((snd_pcm_format_width(runtime->format) != 16) ||
-	    (mod != target))
-		inv = 0;
-	/* Target mod needs inverted DALIGN when 16bit */
-	else
-		inv = 1;
+	dalign = dalign_values[id];
+
+	if (mod == target && snd_pcm_format_width(runtime->format) == 16) {
+		/* Target mod needs inverted DALIGN when 16bit */
+		dalign = (dalign & 0xf0f0f0f0) >> 4 |
+			 (dalign & 0x0f0f0f0f) << 4;
+	}
 
-	return dalign_values[id][inv];
+	return dalign;
 }
 
 u32 rsnd_get_busif_shift(struct rsnd_dai_stream *io, struct rsnd_mod *mod)
-- 
2.17.1

Re: [PATCH] ASoC: rsnd: Calculate DALIGN inversion at run-time

[Eugeniu Rosca]

Hi Geert,

On Mon, Dec 02, 2019 at 04:58:34PM +0100, Geert Uytterhoeven wrote:
> There is no need to store the inverted DALIGN values in the table, as
> they can easily be calculated at run-time.  This also protects against
> the introduction of inconsistencies between normal and inverted values
> by a future table modification.
> 
> Reorder the two subexpressions in the AND check, to perform the least
> expensive check first.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>

> ---
> Compile-tested only.
> 
> Interestingly, this decreases code size on arm64, but increases on arm32
> (both gcc version 7.4.0 (Ubuntu/Linaro 7.4.0-1ubuntu1~18.04.1)).
> 
> arm32:
> 
>        text	   data	    bss	    dec	    hex	filename
>       16186	    276	     84	  16546	   40a2	sound/soc/sh/rcar/core.o.orig
>       16194	    276	     84	  16554	   40aa	sound/soc/sh/rcar/core.o
> 
> arm64:
> 
>        text	   data	    bss	    dec	    hex	filename
>       17426	    392	    104	  17922	   4602	sound/soc/sh/rcar/core.o.orig
>       17414	    392	    104	  17910	   45f6	sound/soc/sh/rcar/core.o
> ---
>  sound/soc/sh/rcar/core.c | 31 +++++++++++++------------------

jFTR, using ARM's aarch64 gcc-8.3-2019.03 and v5.4-10271-g596cf45cbf6e:

$ size sound/soc/sh/rcar/core.o.before sound/soc/sh/rcar/core.o.after
   text	   data	    bss	    dec	    hex	filename
  21433	    380	     88	  21901	   558d	sound/soc/sh/rcar/core.o.before
  21505	    380	     88	  21973	   55d5	sound/soc/sh/rcar/core.o.after

>  1 file changed, 13 insertions(+), 18 deletions(-)
> 
> diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
> index 399dc6e9bde5b042..d20f03dfdee66643 100644
> --- a/sound/soc/sh/rcar/core.c
> +++ b/sound/soc/sh/rcar/core.c
> @@ -376,20 +376,15 @@ u32 rsnd_get_adinr_bit(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
>   */
>  u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
>  {
> -	static const u32 dalign_values[8][2] = {
> -		{0x76543210, 0x67452301},
> -		{0x00000032, 0x00000023},
> -		{0x00007654, 0x00006745},
> -		{0x00000076, 0x00000067},
> -		{0xfedcba98, 0xefcdab89},
> -		{0x000000ba, 0x000000ab},
> -		{0x0000fedc, 0x0000efcd},
> -		{0x000000fe, 0x000000ef},
> +	static const u32 dalign_values[8] = {
> +		0x76543210, 0x00000032, 0x00007654, 0x00000076,
> +		0xfedcba98, 0x000000ba, 0x0000fedc, 0x000000fe,

FWIW, using below test procedure, I can reconstruct the original
two-dimensional dalign_values[8][2] array on the host:

#include <stdio.h>
#include <stdint.h>

typedef uint32_t u32;

void main(void)
{
	u32 dalign, i;

	static const u32 dalign_values[8] = {
		0x76543210, 0x00000032, 0x00007654, 0x00000076,
		0xfedcba98, 0x000000ba, 0x0000fedc, 0x000000fe,
	};

	for (i = 0; i < 8; i++) {
		u32 keep = dalign = dalign_values[i];
		dalign = (dalign & 0xf0f0f0f0) >> 4 |
			 (dalign & 0x0f0f0f0f) << 4;
		printf("{0x%08x, 0x%08x},\n", keep, dalign);
	}
}

-- 
Best Regards,
Eugeniu

Re: [PATCH] ASoC: rsnd: Calculate DALIGN inversion at run-time

[Kuninori Morimoto]

Hi

> There is no need to store the inverted DALIGN values in the table, as
> they can easily be calculated at run-time.  This also protects against
> the introduction of inconsistencies between normal and inverted values
> by a future table modification.
> 
> Reorder the two subexpressions in the AND check, to perform the least
> expensive check first.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---

Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Applied "ASoC: rsnd: Calculate DALIGN inversion at run-time" to the asoc tree

[Mark Brown]

The patch

   ASoC: rsnd: Calculate DALIGN inversion at run-time

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.6

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From 49df1e3925824cf44e590daac635974270185841 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Mon, 2 Dec 2019 16:58:34 +0100
Subject: [PATCH] ASoC: rsnd: Calculate DALIGN inversion at run-time

There is no need to store the inverted DALIGN values in the table, as
they can easily be calculated at run-time.  This also protects against
the introduction of inconsistencies between normal and inverted values
by a future table modification.

Reorder the two subexpressions in the AND check, to perform the least
expensive check first.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/20191202155834.22582-1-geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 sound/soc/sh/rcar/core.c | 31 +++++++++++++------------------
 1 file changed, 13 insertions(+), 18 deletions(-)

diff --git a/sound/soc/sh/rcar/core.c b/sound/soc/sh/rcar/core.c
index 399dc6e9bde5..d20f03dfdee6 100644
--- a/sound/soc/sh/rcar/core.c
+++ b/sound/soc/sh/rcar/core.c
@@ -376,20 +376,15 @@ u32 rsnd_get_adinr_bit(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
  */
 u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
 {
-	static const u32 dalign_values[8][2] = {
-		{0x76543210, 0x67452301},
-		{0x00000032, 0x00000023},
-		{0x00007654, 0x00006745},
-		{0x00000076, 0x00000067},
-		{0xfedcba98, 0xefcdab89},
-		{0x000000ba, 0x000000ab},
-		{0x0000fedc, 0x0000efcd},
-		{0x000000fe, 0x000000ef},
+	static const u32 dalign_values[8] = {
+		0x76543210, 0x00000032, 0x00007654, 0x00000076,
+		0xfedcba98, 0x000000ba, 0x0000fedc, 0x000000fe,
 	};
-	int id = 0, inv;
+	int id = 0;
 	struct rsnd_mod *ssiu = rsnd_io_to_mod_ssiu(io);
 	struct rsnd_mod *target;
 	struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
+	u32 dalign;
 
 	/*
 	 * *Hardware* L/R and *Software* L/R are inverted for 16bit data.
@@ -425,15 +420,15 @@ u32 rsnd_get_dalign(struct rsnd_mod *mod, struct rsnd_dai_stream *io)
 	if (mod == ssiu)
 		id = rsnd_mod_id_sub(mod);
 
-	/* Non target mod or non 16bit needs normal DALIGN */
-	if ((snd_pcm_format_width(runtime->format) != 16) ||
-	    (mod != target))
-		inv = 0;
-	/* Target mod needs inverted DALIGN when 16bit */
-	else
-		inv = 1;
+	dalign = dalign_values[id];
+
+	if (mod == target && snd_pcm_format_width(runtime->format) == 16) {
+		/* Target mod needs inverted DALIGN when 16bit */
+		dalign = (dalign & 0xf0f0f0f0) >> 4 |
+			 (dalign & 0x0f0f0f0f) << 4;
+	}
 
-	return dalign_values[id][inv];
+	return dalign;
 }
 
 u32 rsnd_get_busif_shift(struct rsnd_dai_stream *io, struct rsnd_mod *mod)
-- 
2.20.1