An experimental OSLEC echocan module.

git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@5111 a0bf4364-ded3-4de4-8d8a-66a801d63aff

3 files changed, 141 insertions, 1 deletions

diff --git a/README b/README
index c662719..73c2a95 100644
--- a/README
+++ b/README
@@ -108,7 +108,7 @@ SUBDIRS_EXTRA:
 
 
 Installing the B410P drivers
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 With Zaptel it was possible to install mISDN and the B410P driver by typing
 'make b410p' from the command-line.  This is no longer possible with DAHDI as
 part of the changes to make DAHDI friendlier to binary packagers.  If you
@@ -137,6 +137,34 @@ NOTE:  At the time this was written, misdn-1.1.8 is not compatible the
 2.6.25 kernel.  Please use a kernel version 2.6.25 or earlier.
 
 
+OSLEC
+~~~~~
+OSLEC is a Open Source Line Echo Canceller. Its homepage is at
+http://www.rowetel.com/ucasterisk/oslec.html and is is currently making
+its way into the mainline Kernel tree and may be included at some time
+around 2.6.29 (hopefully). The echo canceller module dahdi_echocan_oslec
+provides a DAHDI echo canceller module that uses the code from OSLEC. As
+OSLEC has not been accepted into mainline yet, its interface is not set
+in stone and thus this driver may need to change. Thus it is not
+built by default.
+
+Luckily the structure of the dahdi-linux tree matches that of the kernel
+tree. Hence you can basically copy drivers/staging/echo and place it
+under driver/staging/echo . In fact, dahdi_echocan_oslec assumes that
+this is where the oslec code lies. If it is elsewhere you'll need to fix
+the #include line.
+
+If you do have the oslec module but get messages about the functions
+'oslec_free', 'oslec_create' and such do not exist, this may be because
+you use a different version of the module. Specifically if it exports 
+'echo_can_free' or 'oslec_echo_can_free' . In that case get the latest
+version of dahdi-linux SVN and of OSLEC (from the staging tree or
+whatever).
+
+For more information regarding installing and using OSLEC, see the OSLEC
+homepage.
+
+
 Module Parameters
 -----------------
 The kernel modules can be configured through module parameters. Module
diff --git a/drivers/dahdi/Kbuild b/drivers/dahdi/Kbuild
index 9213546..a1a2aa9 100644
--- a/drivers/dahdi/Kbuild
+++ b/drivers/dahdi/Kbuild
@@ -28,6 +28,15 @@ obj-$(DAHDI_BUILD_ALL)$(CONFIG_DAHDI_ECHOCAN_MG2)	+= dahdi_echocan_mg2.o
 
 obj-m += $(DAHDI_MODULES_EXTRA)
 
+# Only enable this if you think you know what you're doing. This is not
+# supported yet:
+#obj-m += dahdi_echocan_oslec.o
+#
+# A quick and dirty way to build OSLEC, if you happened to place it
+# yourself in the dahdi source tree. This is experimental. See README
+# regarding OSLEC.
+#obj-m += ../staging/echo/
+
 CFLAGS_MODULE += -I$(DAHDI_INCLUDE) -I$(src)
 
 ifndef HOTPLUG_FIRMWARE
diff --git a/drivers/dahdi/dahdi_echocan_oslec.c b/drivers/dahdi/dahdi_echocan_oslec.c
new file mode 100644
index 0000000..b0c7779
--- /dev/null
+++ b/drivers/dahdi/dahdi_echocan_oslec.c
@@ -0,0 +1,103 @@
+/*
+ * DAHDI Telephony Interface to the Open Source Line Echo Canceller (OSLEC)
+ *
+ * Written by Tzafrir Cohen <tzafrir.cohen@xorcom.com>
+ * Copyright (C) 2008 Xorcom, Inc.
+ *
+ * All rights reserved.
+ *
+ * Based on dahdi_echocan_hpec.c, Copyright (C) 2006-2008 Digium, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ * 
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA. 
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+#include <linux/moduleparam.h>
+
+/* Fix this if OSLEC is elsewhere */
+#include "../staging/echo/oslec.h"
+//#include <linux/oslec.h>
+/* "provide" struct echo_can_state */
+//#define oslec_state echo_can_state
+
+#include <dahdi/kernel.h>
+
+#define module_printk(level, fmt, args...) printk(level "%s: " fmt, THIS_MODULE->name, ## args)
+
+static void echo_can_free(struct echo_can_state *ec)
+{
+	oslec_free((struct oslec_state *)ec);
+}
+
+static void echo_can_update(struct echo_can_state *ec, short *iref, short *isig)
+{
+	oslec_update((struct oslec_state *)ec, *iref, *isig);
+}
+
+static int echo_can_create(struct dahdi_echocanparams *ecp, struct dahdi_echocanparam *p,
+			   struct echo_can_state **ec)
+{
+	if (ecp->param_count > 0) {
+		printk(KERN_WARNING "OSLEC does not support parameters; failing request\n");
+		return -EINVAL;
+	}
+
+	/* TODO: get adaption mode from EC parameters? */
+	*ec = (struct echo_can_state *)oslec_create(ecp->tap_length, 0);
+
+	return *ec ? 0 : -ENOTTY;
+}
+
+static inline int echo_can_traintap(struct echo_can_state *ec, int pos, short val)
+{
+	return 1;
+}
+
+static const struct dahdi_echocan me = {
+	.name = "OSLEC",
+	.owner = THIS_MODULE,
+	.echo_can_create = echo_can_create,
+	.echo_can_free = echo_can_free,
+	.echo_can_array_update = echo_can_update,
+	.echo_can_traintap = echo_can_traintap,
+};
+
+static int __init mod_init(void)
+{
+	if (dahdi_register_echocan(&me)) {
+		module_printk(KERN_ERR, "could not register with DAHDI core\n");
+
+		return -EPERM;
+	}
+
+	module_printk(KERN_INFO, "Registered echo canceler '%s'\n", me.name);
+
+	return 0;
+}
+
+static void __exit mod_exit(void)
+{
+	dahdi_unregister_echocan(&me);
+}
+
+MODULE_DESCRIPTION("DAHDI OSLEC wrapper");
+MODULE_AUTHOR("Tzafrir Cohen <tzafrir.cohen@xorcom.com>");
+MODULE_LICENSE("GPL");
+
+module_init(mod_init);
+module_exit(mod_exit);