linux/drivers/isdn/mISDN/dsp_hwec.c

/*
 * dsp_hwec.c:
 * builtin mISDN dsp pipeline element for enabling the hw echocanceller
 *
 * Copyright (C) 2007, Nadi Sarrar
 *
 * Nadi Sarrar <nadi@beronet.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called LICENSE.
 *
 */

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mISDNdsp.h>
#include <linux/mISDNif.h>
#include "core.h"
#include "dsp.h"
#include "dsp_hwec.h"

static struct mISDN_dsp_element_arg args[] = {
	{ "deftaps", "128", "Set the number of taps of cancellation." },
};

static struct mISDN_dsp_element dsp_hwec_p = {
	.name = "hwec",
	.new = NULL,
	.free = NULL,
	.process_tx = NULL,
	.process_rx = NULL,
	.num_args = ARRAY_SIZE(args),
	.args = args,
};
struct mISDN_dsp_element *dsp_hwec = &dsp_hwec_p;

void dsp_hwec_enable(struct dsp *dsp, const char *arg)
{
	int deftaps = 128,
		len;
	struct mISDN_ctrl_req	cq;

	if (!dsp) {
		printk(KERN_ERR "%s: failed to enable hwec: dsp is NULL\n",
			__func__);
		return;
	}

	if (!arg)
		goto _do;

	len = strlen(arg);
	if (!len)
		goto _do;

	{
		char _dup[len + 1];
		char *dup, *tok, *name, *val;
		int tmp;

		strcpy(_dup, arg);
		dup = _dup;

		while ((tok = strsep(&dup, ","))) {
			if (!strlen(tok))
				continue;
			name = strsep(&tok, "=");
			val = tok;

			if (!val)
				continue;

			if (!strcmp(name, "deftaps")) {
				if (sscanf(val, "%d", &tmp) == 1)
					deftaps = tmp;
			}
		}
	}

_do:
	printk(KERN_DEBUG "%s: enabling hwec with deftaps=%d\n",
		__func__, deftaps);
	memset(&cq, 0, sizeof(cq));
	cq.op = MISDN_CTRL_HFC_ECHOCAN_ON;
	cq.p1 = deftaps;
	if (!dsp->ch.peer->ctrl(&dsp->ch, CONTROL_CHANNEL, &cq)) {
		printk(KERN_DEBUG "%s: CONTROL_CHANNEL failed\n",
			__func__);
		return;
	}
}

void dsp_hwec_disable(struct dsp *dsp)
{
	struct mISDN_ctrl_req	cq;

	if (!dsp) {
		printk(KERN_ERR "%s: failed to disable hwec: dsp is NULL\n",
			__func__);
		return;
	}

	printk(KERN_DEBUG "%s: disabling hwec\n", __func__);
	memset(&cq, 0, sizeof(cq));
	cq.op = MISDN_CTRL_HFC_ECHOCAN_OFF;
	if (!dsp->ch.peer->ctrl(&dsp->ch, CONTROL_CHANNEL, &cq)) {
		printk(KERN_DEBUG "%s: CONTROL_CHANNEL failed\n",
			__func__);
		return;
	}
}

int dsp_hwec_init(void)
{
	mISDN_dsp_element_register(dsp_hwec);

	return 0;
}

void dsp_hwec_exit(void)
{
	mISDN_dsp_element_unregister(dsp_hwec);
}