Add mISDN DSP

Enable support for digital audio processing capability.
This module may be used for special applications that require
cross connecting of bchannels, conferencing, dtmf decoding
echo cancelation, tone generation, and Blowfish encryption and
decryption.
It may use hardware features if available.

Signed-off-by: Karsten Keil <kkeil@suse.de>

1 files changed, 138 insertions, 0 deletions

diff --git a/drivers/isdn/mISDN/dsp_hwec.c b/drivers/isdn/mISDN/dsp_hwec.c
new file mode 100644
index 000000000000..eb892d9dd5c6
--- /dev/null
+++ b/drivers/isdn/mISDN/dsp_hwec.c
@@ -0,0 +1,138 @@
+/*
+ * 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 = sizeof(args) / sizeof(struct mISDN_dsp_element_arg),
+	.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);
+}
+