plugin: alsaplug: Add kcontrol set up callback

Define the callback for setting up kcontrols in the plugin. Add a few
new fields in struct plug_shm_ctl to store the module info and the
volume table for converting mixer values to linear volume gain.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

Author: ranj063

tools/plugin/README.md

@@ -70,11 +70,16 @@ arecord -Dsof:plugin:1:default:default:48k2c16b -f dat file.wav
 ```
 Will record audio using the plugin topology and PCM ID 1.
 
-Mixer settings can be adjusted for sof-plugin by (Not functional yet)
+Mixer settings can be adjusted for sof-plugin by
 
 ```
-alsamixer -Dsof:sof-plugin:1
+alsamixer -Dsof:plugin
 ```
+or
+```
+amixer -Dsof:plugin cset numid=1 20
+```
+Right now, only volume controls are supported. Support for bytes and enum controls is pending.
 
 # Instructions for testing OpenVino noise suppression model with the SOF plugin:
 1. Fetch the model from the Open Model zoo repository ex: noise-suppression-poconetlike-0001.xml

tools/plugin/alsaplug/CMakeLists.txt

@@ -6,6 +6,7 @@ add_library(asound_module_pcm_sof MODULE
 	plugin.c
 	../common.c
 	tplg.c
+	tplg_ctl.c
 )
 
 sof_append_relative_path_definitions(asound_module_pcm_sof)

tools/plugin/alsaplug/plugin.h

@@ -64,5 +64,6 @@ int plug_parse_topology(snd_sof_plug_t *plug);
 int plug_set_up_pipelines(snd_sof_plug_t *plug, int dir);
 int plug_free_pipelines(snd_sof_plug_t *plug, struct tplg_pipeline_list *pipeline_list, int dir);
 void plug_free_topology(snd_sof_plug_t *plug);
+int plug_kcontrol_cb_new(struct snd_soc_tplg_ctl_hdr *tplg_ctl, void *_comp, void *arg);
 
 #endif

tools/plugin/alsaplug/tplg.c

@@ -750,9 +750,8 @@ int plug_parse_topology(snd_sof_plug_t *plug)
 
 	tplg_debug("parsing topology file %s\n", ctx->tplg_file);
 
-	/* TODO: ctl callback */
-//	ctx->ctl_arg = sp;
-//	ctx->ctl_cb = pipe_kcontrol_cb_new;
+	ctx->ctl_arg = plug;
+	ctx->ctl_cb = plug_kcontrol_cb_new;
 
 	/* open topology file */
 	file = fopen(ctx->tplg_file, "rb");

tools/plugin/alsaplug/tplg_ctl.c

@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// Copyright(c) 2024 Intel Corporation. All rights reserved.
+//
+
+/* SOF topology kcontrols */
+
+#include <stdio.h>
+#include <sys/poll.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <mqueue.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <semaphore.h>
+#include <assert.h>
+#include <errno.h>
+#include <math.h>
+
+#include <alsa/asoundlib.h>
+#include <alsa/pcm_external.h>
+
+#include <rtos/sof.h>
+#include <sof/audio/pipeline.h>
+#include <sof/audio/component.h>
+#include <ipc/stream.h>
+#include <tplg_parser/topology.h>
+
+#include "plugin.h"
+#include "common.h"
+
+#define SOF_IPC4_VOL_ZERO_DB	0x7fffffff
+#define VOLUME_FWL      16
+/*
+ * Constants used in the computation of linear volume gain
+ * from dB gain 20th root of 10 in Q1.16 fixed-point notation
+ */
+#define VOL_TWENTIETH_ROOT_OF_TEN	73533
+/* 40th root of 10 in Q1.16 fixed-point notation*/
+#define VOL_FORTIETH_ROOT_OF_TEN	69419
+
+/* 0.5 dB step value in topology TLV */
+#define VOL_HALF_DB_STEP	50
+
+/*
+ * Function to truncate an unsigned 64-bit number
+ * by x bits and return 32-bit unsigned number. This
+ * function also takes care of rounding while truncating
+ */
+static uint32_t vol_shift_64(uint64_t i, uint32_t x)
+{
+	if (x == 0)
+		return (uint32_t)i;
+
+	/* do not truncate more than 32 bits */
+	if (x > 32)
+		x = 32;
+
+	return (uint32_t)(((i >> (x - 1)) + 1) >> 1);
+}
+
+/*
+ * Function to compute a ** exp where,
+ * a is a fractional number represented by a fixed-point integer with a fractional word length
+ * of "fwl"
+ * exp is an integer
+ * fwl is the fractional word length
+ * Return value is a fractional number represented by a fixed-point integer with a fractional
+ * word length of "fwl"
+ */
+static uint32_t vol_pow32(uint32_t a, int exp, uint32_t fwl)
+{
+	int i, iter;
+	uint32_t power = 1 << fwl;
+	unsigned long long numerator;
+
+	/* if exponent is 0, return 1 */
+	if (exp == 0)
+		return power;
+
+	/* determine the number of iterations based on the exponent */
+	if (exp < 0)
+		iter = exp * -1;
+	else
+		iter = exp;
+
+	/* multiply a "iter" times to compute power */
+	for (i = 0; i < iter; i++) {
+		/*
+		 * Product of 2 Qx.fwl fixed-point numbers yields a Q2*x.2*fwl
+		 * Truncate product back to fwl fractional bits with rounding
+		 */
+		power = vol_shift_64((uint64_t)power * a, fwl);
+	}
+
+	if (exp > 0) {
+		/* if exp is positive, return the result */
+		return power;
+	}
+
+	/* if exp is negative, return the multiplicative inverse */
+	numerator = (uint64_t)1 << (fwl << 1);
+	numerator /= power;
+
+	return (uint32_t)numerator;
+}
+
+/*
+ * Function to calculate volume gain from TLV data.
+ * This function can only handle gain steps that are multiples of 0.5 dB
+ */
+static uint32_t vol_compute_gain(uint32_t value, struct snd_soc_tplg_tlv_dbscale *scale)
+{
+	int dB_gain;
+	uint32_t linear_gain;
+	int f_step;
+
+	/* mute volume */
+	if (value == 0 && scale->mute)
+		return 0;
+
+	/* compute dB gain from tlv. tlv_step in topology is multiplied by 100 */
+	dB_gain = (int)scale->min / 100 + (value * scale->step) / 100;
+
+	/* compute linear gain represented by fixed-point int with VOLUME_FWL fractional bits */
+	linear_gain = vol_pow32(VOL_TWENTIETH_ROOT_OF_TEN, dB_gain, VOLUME_FWL);
+
+	/* extract the fractional part of volume step */
+	f_step = scale->step - (scale->step / 100);
+
+	/* if volume step is an odd multiple of 0.5 dB */
+	if (f_step == VOL_HALF_DB_STEP && (value & 1))
+		linear_gain = vol_shift_64((uint64_t)linear_gain * VOL_FORTIETH_ROOT_OF_TEN,
+					   VOLUME_FWL);
+
+	return linear_gain;
+}
+
+/* helper function to add new kcontrols to the list of kcontrols in the global context */
+int plug_kcontrol_cb_new(struct snd_soc_tplg_ctl_hdr *tplg_ctl, void *_comp, void *arg)
+{
+	snd_sof_plug_t *plug = arg;
+	struct plug_shm_glb_state *glb = plug->glb_ctx.addr;
+	struct plug_shm_ctl *ctl;
+
+	if (glb->num_ctls >= MAX_CTLS) {
+		SNDERR("Failed to add a new control. Too many controls already\n");
+		return -EINVAL;
+	}
+
+	switch (tplg_ctl->type) {
+	case SND_SOC_TPLG_CTL_VOLSW:
+	case SND_SOC_TPLG_CTL_VOLSW_SX:
+	case SND_SOC_TPLG_CTL_VOLSW_XR_SX:
+	{
+		struct snd_soc_tplg_mixer_control *tplg_mixer =
+			(struct snd_soc_tplg_mixer_control *)tplg_ctl;
+		struct tplg_comp_info *comp_info = _comp;
+		struct snd_soc_tplg_ctl_tlv *tlv;
+		struct snd_soc_tplg_tlv_dbscale *scale;
+		int i;
+
+		glb->size += sizeof(struct plug_shm_ctl);
+		ctl = &glb->ctl[glb->num_ctls++];
+		ctl->module_id = comp_info->module_id;
+		ctl->instance_id = comp_info->instance_id;
+		ctl->mixer_ctl = *tplg_mixer;
+		tlv = &tplg_ctl->tlv;
+		scale = &tlv->scale;
+
+		/* populate the volume table */
+		for (i = 0; i < tplg_mixer->max + 1 ; i++) {
+			uint32_t val = vol_compute_gain(i, scale);
+
+			/* Can be over Q1.31, need to saturate */
+			uint64_t q31val = ((uint64_t)val) << 15;
+
+			ctl->volume_table[i] = q31val > SOF_IPC4_VOL_ZERO_DB ?
+							SOF_IPC4_VOL_ZERO_DB : q31val;
+		}
+		break;
+	}
+	case SND_SOC_TPLG_CTL_ENUM:
+	case SND_SOC_TPLG_CTL_ENUM_VALUE:
+	case SND_SOC_TPLG_CTL_BYTES:
+		break;
+	case SND_SOC_TPLG_CTL_RANGE:
+	case SND_SOC_TPLG_CTL_STROBE:
+	default:
+		SNDERR("Invalid ctl type %d\n", tplg_ctl->type);
+		return -EINVAL;
+	}
+
+	return 0;
+}

tools/plugin/common.h

@@ -51,6 +51,7 @@
 #endif
 
 #define SOF_MAGIC	"sofpipe"
+#define MAX_VOLUME_SIZE 120
 
 enum plugin_state {
 	SOF_PLUGIN_STATE_INIT	= 0,
@@ -61,8 +62,10 @@ enum plugin_state {
 };
 
 struct plug_shm_ctl {
-	unsigned int comp_id;
+	unsigned int module_id;
+	unsigned int instance_id;
 	unsigned int type;
+	unsigned int volume_table[MAX_VOLUME_SIZE];
 	union {
 		struct snd_soc_tplg_mixer_control mixer_ctl;
 		struct snd_soc_tplg_enum_control enum_ctl;

tools/plugin/pipe/CMakeLists.txt

@@ -4,7 +4,6 @@ add_executable(sof-pipe
 	main.c
 	cpu.c
 	pipeline.c
-	ctl.c
 	ipc4.c
 	../common.c
 )