v4.19.13 snapshot.
diff --git a/drivers/isdn/mISDN/dsp_pipeline.c b/drivers/isdn/mISDN/dsp_pipeline.c
new file mode 100644
index 0000000..e72b4e7
--- /dev/null
+++ b/drivers/isdn/mISDN/dsp_pipeline.c
@@ -0,0 +1,354 @@
+/*
+ * dsp_pipeline.c: pipelined audio processing
+ *
+ * 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/slab.h>
+#include <linux/list.h>
+#include <linux/string.h>
+#include <linux/mISDNif.h>
+#include <linux/mISDNdsp.h>
+#include <linux/export.h>
+#include "dsp.h"
+#include "dsp_hwec.h"
+
+/* uncomment for debugging */
+/*#define PIPELINE_DEBUG*/
+
+struct dsp_pipeline_entry {
+	struct mISDN_dsp_element *elem;
+	void                *p;
+	struct list_head     list;
+};
+struct dsp_element_entry {
+	struct mISDN_dsp_element *elem;
+	struct device	     dev;
+	struct list_head     list;
+};
+
+static LIST_HEAD(dsp_elements);
+
+/* sysfs */
+static struct class *elements_class;
+
+static ssize_t
+attr_show_args(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct mISDN_dsp_element *elem = dev_get_drvdata(dev);
+	int i;
+	char *p = buf;
+
+	*buf = 0;
+	for (i = 0; i < elem->num_args; i++)
+		p += sprintf(p, "Name:        %s\n%s%s%sDescription: %s\n\n",
+			     elem->args[i].name,
+			     elem->args[i].def ? "Default:     " : "",
+			     elem->args[i].def ? elem->args[i].def : "",
+			     elem->args[i].def ? "\n" : "",
+			     elem->args[i].desc);
+
+	return p - buf;
+}
+
+static struct device_attribute element_attributes[] = {
+	__ATTR(args, 0444, attr_show_args, NULL),
+};
+
+static void
+mISDN_dsp_dev_release(struct device *dev)
+{
+	struct dsp_element_entry *entry =
+		container_of(dev, struct dsp_element_entry, dev);
+	list_del(&entry->list);
+	kfree(entry);
+}
+
+int mISDN_dsp_element_register(struct mISDN_dsp_element *elem)
+{
+	struct dsp_element_entry *entry;
+	int ret, i;
+
+	if (!elem)
+		return -EINVAL;
+
+	entry = kzalloc(sizeof(struct dsp_element_entry), GFP_ATOMIC);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->elem = elem;
+
+	entry->dev.class = elements_class;
+	entry->dev.release = mISDN_dsp_dev_release;
+	dev_set_drvdata(&entry->dev, elem);
+	dev_set_name(&entry->dev, "%s", elem->name);
+	ret = device_register(&entry->dev);
+	if (ret) {
+		printk(KERN_ERR "%s: failed to register %s\n",
+		       __func__, elem->name);
+		goto err1;
+	}
+	list_add_tail(&entry->list, &dsp_elements);
+
+	for (i = 0; i < ARRAY_SIZE(element_attributes); ++i) {
+		ret = device_create_file(&entry->dev,
+					 &element_attributes[i]);
+		if (ret) {
+			printk(KERN_ERR "%s: failed to create device file\n",
+			       __func__);
+			goto err2;
+		}
+	}
+
+#ifdef PIPELINE_DEBUG
+	printk(KERN_DEBUG "%s: %s registered\n", __func__, elem->name);
+#endif
+
+	return 0;
+
+err2:
+	device_unregister(&entry->dev);
+	return ret;
+err1:
+	kfree(entry);
+	return ret;
+}
+EXPORT_SYMBOL(mISDN_dsp_element_register);
+
+void mISDN_dsp_element_unregister(struct mISDN_dsp_element *elem)
+{
+	struct dsp_element_entry *entry, *n;
+
+	if (!elem)
+		return;
+
+	list_for_each_entry_safe(entry, n, &dsp_elements, list)
+		if (entry->elem == elem) {
+			device_unregister(&entry->dev);
+#ifdef PIPELINE_DEBUG
+			printk(KERN_DEBUG "%s: %s unregistered\n",
+			       __func__, elem->name);
+#endif
+			return;
+		}
+	printk(KERN_ERR "%s: element %s not in list.\n", __func__, elem->name);
+}
+EXPORT_SYMBOL(mISDN_dsp_element_unregister);
+
+int dsp_pipeline_module_init(void)
+{
+	elements_class = class_create(THIS_MODULE, "dsp_pipeline");
+	if (IS_ERR(elements_class))
+		return PTR_ERR(elements_class);
+
+#ifdef PIPELINE_DEBUG
+	printk(KERN_DEBUG "%s: dsp pipeline module initialized\n", __func__);
+#endif
+
+	dsp_hwec_init();
+
+	return 0;
+}
+
+void dsp_pipeline_module_exit(void)
+{
+	struct dsp_element_entry *entry, *n;
+
+	dsp_hwec_exit();
+
+	class_destroy(elements_class);
+
+	list_for_each_entry_safe(entry, n, &dsp_elements, list) {
+		list_del(&entry->list);
+		printk(KERN_WARNING "%s: element was still registered: %s\n",
+		       __func__, entry->elem->name);
+		kfree(entry);
+	}
+
+#ifdef PIPELINE_DEBUG
+	printk(KERN_DEBUG "%s: dsp pipeline module exited\n", __func__);
+#endif
+}
+
+int dsp_pipeline_init(struct dsp_pipeline *pipeline)
+{
+	if (!pipeline)
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&pipeline->list);
+
+#ifdef PIPELINE_DEBUG
+	printk(KERN_DEBUG "%s: dsp pipeline ready\n", __func__);
+#endif
+
+	return 0;
+}
+
+static inline void _dsp_pipeline_destroy(struct dsp_pipeline *pipeline)
+{
+	struct dsp_pipeline_entry *entry, *n;
+
+	list_for_each_entry_safe(entry, n, &pipeline->list, list) {
+		list_del(&entry->list);
+		if (entry->elem == dsp_hwec)
+			dsp_hwec_disable(container_of(pipeline, struct dsp,
+						      pipeline));
+		else
+			entry->elem->free(entry->p);
+		kfree(entry);
+	}
+}
+
+void dsp_pipeline_destroy(struct dsp_pipeline *pipeline)
+{
+
+	if (!pipeline)
+		return;
+
+	_dsp_pipeline_destroy(pipeline);
+
+#ifdef PIPELINE_DEBUG
+	printk(KERN_DEBUG "%s: dsp pipeline destroyed\n", __func__);
+#endif
+}
+
+int dsp_pipeline_build(struct dsp_pipeline *pipeline, const char *cfg)
+{
+	int incomplete = 0, found = 0;
+	char *dup, *tok, *name, *args;
+	struct dsp_element_entry *entry, *n;
+	struct dsp_pipeline_entry *pipeline_entry;
+	struct mISDN_dsp_element *elem;
+
+	if (!pipeline)
+		return -EINVAL;
+
+	if (!list_empty(&pipeline->list))
+		_dsp_pipeline_destroy(pipeline);
+
+	dup = kstrdup(cfg, GFP_ATOMIC);
+	if (!dup)
+		return 0;
+	while ((tok = strsep(&dup, "|"))) {
+		if (!strlen(tok))
+			continue;
+		name = strsep(&tok, "(");
+		args = strsep(&tok, ")");
+		if (args && !*args)
+			args = NULL;
+
+		list_for_each_entry_safe(entry, n, &dsp_elements, list)
+			if (!strcmp(entry->elem->name, name)) {
+				elem = entry->elem;
+
+				pipeline_entry = kmalloc(sizeof(struct
+								dsp_pipeline_entry), GFP_ATOMIC);
+				if (!pipeline_entry) {
+					printk(KERN_ERR "%s: failed to add "
+					       "entry to pipeline: %s (out of "
+					       "memory)\n", __func__, elem->name);
+					incomplete = 1;
+					goto _out;
+				}
+				pipeline_entry->elem = elem;
+
+				if (elem == dsp_hwec) {
+					/* This is a hack to make the hwec
+					   available as a pipeline module */
+					dsp_hwec_enable(container_of(pipeline,
+								     struct dsp, pipeline), args);
+					list_add_tail(&pipeline_entry->list,
+						      &pipeline->list);
+				} else {
+					pipeline_entry->p = elem->new(args);
+					if (pipeline_entry->p) {
+						list_add_tail(&pipeline_entry->
+							      list, &pipeline->list);
+#ifdef PIPELINE_DEBUG
+						printk(KERN_DEBUG "%s: created "
+						       "instance of %s%s%s\n",
+						       __func__, name, args ?
+						       " with args " : "", args ?
+						       args : "");
+#endif
+					} else {
+						printk(KERN_ERR "%s: failed "
+						       "to add entry to pipeline: "
+						       "%s (new() returned NULL)\n",
+						       __func__, elem->name);
+						kfree(pipeline_entry);
+						incomplete = 1;
+					}
+				}
+				found = 1;
+				break;
+			}
+
+		if (found)
+			found = 0;
+		else {
+			printk(KERN_ERR "%s: element not found, skipping: "
+			       "%s\n", __func__, name);
+			incomplete = 1;
+		}
+	}
+
+_out:
+	if (!list_empty(&pipeline->list))
+		pipeline->inuse = 1;
+	else
+		pipeline->inuse = 0;
+
+#ifdef PIPELINE_DEBUG
+	printk(KERN_DEBUG "%s: dsp pipeline built%s: %s\n",
+	       __func__, incomplete ? " incomplete" : "", cfg);
+#endif
+	kfree(dup);
+	return 0;
+}
+
+void dsp_pipeline_process_tx(struct dsp_pipeline *pipeline, u8 *data, int len)
+{
+	struct dsp_pipeline_entry *entry;
+
+	if (!pipeline)
+		return;
+
+	list_for_each_entry(entry, &pipeline->list, list)
+		if (entry->elem->process_tx)
+			entry->elem->process_tx(entry->p, data, len);
+}
+
+void dsp_pipeline_process_rx(struct dsp_pipeline *pipeline, u8 *data, int len,
+			     unsigned int txlen)
+{
+	struct dsp_pipeline_entry *entry;
+
+	if (!pipeline)
+		return;
+
+	list_for_each_entry_reverse(entry, &pipeline->list, list)
+		if (entry->elem->process_rx)
+			entry->elem->process_rx(entry->p, data, len, txlen);
+}