staging: ozwpan: Added device state support

Added support for maintaining state and data buffering for devices
connected via the network.

Signed-off-by: Chris Kelly <ckelly@ozmodevices.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ozwpan/ozeltbuf.c

@@ -0,0 +1,339 @@
+/* -----------------------------------------------------------------------------
+ * Copyright (c) 2011 Ozmo Inc
+ * Released under the GNU General Public License Version 2 (GPLv2).
+ * -----------------------------------------------------------------------------
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include "ozconfig.h"
+#include "ozprotocol.h"
+#include "ozeltbuf.h"
+#include "ozpd.h"
+#include "oztrace.h"
+#include "ozalloc.h"
+/*------------------------------------------------------------------------------
+ */
+#define OZ_ELT_INFO_MAGIC_USED	0x35791057
+#define OZ_ELT_INFO_MAGIC_FREE	0x78940102
+/*------------------------------------------------------------------------------
+ * Context: softirq-serialized
+ */
+int oz_elt_buf_init(struct oz_elt_buf *buf)
+{
+	memset(buf, 0, sizeof(struct oz_elt_buf));
+	INIT_LIST_HEAD(&buf->stream_list);
+	INIT_LIST_HEAD(&buf->order_list);
+	INIT_LIST_HEAD(&buf->isoc_list);
+	buf->max_free_elts = 32;
+	spin_lock_init(&buf->lock);
+	return 0;
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq or process
+ */
+void oz_elt_buf_term(struct oz_elt_buf *buf)
+{
+	struct list_head *e;
+	int i;
+	/* Free any elements in the order or isoc lists. */
+	for (i = 0; i < 2; i++) {
+		struct list_head *list;
+		if (i)
+			list = &buf->order_list;
+		else
+			list = &buf->isoc_list;
+		e = list->next;
+		while (e != list) {
+			struct oz_elt_info *ei =
+				container_of(e, struct oz_elt_info, link_order);
+			e = e->next;
+			oz_free(ei);
+		}
+	}
+	/* Free any elelment in the pool. */
+	while (buf->elt_pool) {
+		struct oz_elt_info *ei =
+			container_of(buf->elt_pool, struct oz_elt_info, link);
+		buf->elt_pool = buf->elt_pool->next;
+		oz_free(ei);
+	}
+	buf->free_elts = 0;
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq or process
+ */
+struct oz_elt_info *oz_elt_info_alloc(struct oz_elt_buf *buf)
+{
+	struct oz_elt_info *ei = 0;
+	spin_lock_bh(&buf->lock);
+	if (buf->free_elts && buf->elt_pool) {
+		ei = container_of(buf->elt_pool, struct oz_elt_info, link);
+		buf->elt_pool = ei->link.next;
+		buf->free_elts--;
+		spin_unlock_bh(&buf->lock);
+		if (ei->magic != OZ_ELT_INFO_MAGIC_FREE) {
+			oz_trace("oz_elt_info_alloc: ei with bad magic: 0x%x\n",
+				ei->magic);
+		}
+	} else {
+		spin_unlock_bh(&buf->lock);
+		ei = oz_alloc(sizeof(struct oz_elt_info), GFP_ATOMIC);
+	}
+	if (ei) {
+		ei->flags = 0;
+		ei->app_id = 0;
+		ei->callback = 0;
+		ei->context = 0;
+		ei->stream = 0;
+		ei->magic = OZ_ELT_INFO_MAGIC_USED;
+		INIT_LIST_HEAD(&ei->link);
+		INIT_LIST_HEAD(&ei->link_order);
+	}
+	return ei;
+}
+/*------------------------------------------------------------------------------
+ * Precondition: oz_elt_buf.lock must be held.
+ * Context: softirq or process
+ */
+void oz_elt_info_free(struct oz_elt_buf *buf, struct oz_elt_info *ei)
+{
+	if (ei) {
+		if (ei->magic == OZ_ELT_INFO_MAGIC_USED) {
+			buf->free_elts++;
+			ei->link.next = buf->elt_pool;
+			buf->elt_pool = &ei->link;
+			ei->magic = OZ_ELT_INFO_MAGIC_FREE;
+		} else {
+			oz_trace("oz_elt_info_free: bad magic ei: %p"
+				" magic: 0x%x\n",
+				ei, ei->magic);
+		}
+	}
+}
+/*------------------------------------------------------------------------------
+ * Context: softirq
+ */
+void oz_elt_info_free_chain(struct oz_elt_buf *buf, struct list_head *list)
+{
+	struct list_head *e;
+	e = list->next;
+	spin_lock_bh(&buf->lock);
+	while (e != list) {
+		struct oz_elt_info *ei;
+		ei = container_of(e, struct oz_elt_info, link);
+		e = e->next;
+		oz_elt_info_free(buf, ei);
+	}
+	spin_unlock_bh(&buf->lock);
+}
+/*------------------------------------------------------------------------------
+ */
+int oz_elt_stream_create(struct oz_elt_buf *buf, u8 id, int max_buf_count)
+{
+	struct oz_elt_stream *st =
+		oz_alloc(sizeof(struct oz_elt_stream), GFP_ATOMIC | __GFP_ZERO);
+	oz_trace("oz_elt_stream_create(0x%x)\n", id);
+	if (st == 0)
+		return -1;
+	memset(st, 0, sizeof(struct oz_elt_stream));
+	atomic_set(&st->ref_count, 1);
+	st->id = id;
+	st->max_buf_count = max_buf_count;
+	INIT_LIST_HEAD(&st->elt_list);
+	spin_lock_bh(&buf->lock);
+	list_add_tail(&st->link, &buf->stream_list);
+	spin_unlock_bh(&buf->lock);
+	return 0;
+}
+/*------------------------------------------------------------------------------
+ */
+int oz_elt_stream_delete(struct oz_elt_buf *buf, u8 id)
+{
+	struct list_head *e;
+	struct oz_elt_stream *st;
+	oz_trace("oz_elt_stream_delete(0x%x)\n", id);
+	spin_lock_bh(&buf->lock);
+	e = buf->stream_list.next;
+	while (e != &buf->stream_list) {
+		st = container_of(e, struct oz_elt_stream, link);
+		if (st->id == id) {
+			list_del(e);
+			break;
+		}
+		st = 0;
+	}
+	if (!st) {
+		spin_unlock_bh(&buf->lock);
+		return -1;
+	}
+	e = st->elt_list.next;
+	while (e != &st->elt_list) {
+		struct oz_elt_info *ei =
+			container_of(e, struct oz_elt_info, link);
+		e = e->next;
+		list_del_init(&ei->link);
+		list_del_init(&ei->link_order);
+		st->buf_count -= ei->length;
+		oz_trace2(OZ_TRACE_STREAM, "Stream down: %d  %d %d\n",
+			st->buf_count,
+			ei->length, atomic_read(&st->ref_count));
+		oz_elt_stream_put(st);
+		oz_elt_info_free(buf, ei);
+	}
+	spin_unlock_bh(&buf->lock);
+	oz_elt_stream_put(st);
+	return 0;
+}
+/*------------------------------------------------------------------------------
+ */
+void oz_elt_stream_get(struct oz_elt_stream *st)
+{
+	atomic_inc(&st->ref_count);
+}
+/*------------------------------------------------------------------------------
+ */
+void oz_elt_stream_put(struct oz_elt_stream *st)
+{
+	if (atomic_dec_and_test(&st->ref_count)) {
+		oz_trace("Stream destroyed\n");
+		oz_free(st);
+	}
+}
+/*------------------------------------------------------------------------------
+ * Precondition: Element buffer lock must be held.
+ * If this function fails the caller is responsible for deallocating the elt
+ * info structure.
+ */
+int oz_queue_elt_info(struct oz_elt_buf *buf, u8 isoc, u8 id,
+	struct oz_elt_info *ei)
+{
+	struct oz_elt_stream *st = 0;
+	struct list_head *e;
+	if (id) {
+		list_for_each(e, &buf->stream_list) {
+			st = container_of(e, struct oz_elt_stream, link);
+			if (st->id == id)
+				break;
+		}
+		if (e == &buf->stream_list) {
+			/* Stream specified but stream not known so fail.
+			 * Caller deallocates element info. */
+			return -1;
+		}
+	}
+	if (st) {
+		/* If this is an ISOC fixed element that needs a frame number
+		 * then insert that now. Earlier we stored the unit count in
+		 * this field.
+		 */
+		struct oz_isoc_fixed *body = (struct oz_isoc_fixed *)
+			&ei->data[sizeof(struct oz_elt)];
+		if ((body->app_id == OZ_APPID_USB) && (body->type
+			== OZ_USB_ENDPOINT_DATA) &&
+			(body->format == OZ_DATA_F_ISOC_FIXED)) {
+			u8 unit_count = body->frame_number;
+			body->frame_number = st->frame_number;
+			st->frame_number += unit_count;
+		}
+		/* Claim stream and update accounts */
+		oz_elt_stream_get(st);
+		ei->stream = st;
+		st->buf_count += ei->length;
+		/* Add to list in stream. */
+		list_add_tail(&ei->link, &st->elt_list);
+		oz_trace2(OZ_TRACE_STREAM, "Stream up: %d  %d\n",
+			st->buf_count, ei->length);
+		/* Check if we have too much buffered for this stream. If so
+		 * start dropping elements until we are back in bounds.
+		 */
+		while ((st->buf_count > st->max_buf_count) &&
+			!list_empty(&st->elt_list)) {
+			struct oz_elt_info *ei2 =
+				list_first_entry(&st->elt_list,
+					struct oz_elt_info, link);
+			list_del_init(&ei2->link);
+			list_del_init(&ei2->link_order);
+			st->buf_count -= ei2->length;
+			oz_elt_info_free(buf, ei2);
+			oz_elt_stream_put(st);
+		}
+	}
+	list_add_tail(&ei->link_order, isoc ?
+		&buf->isoc_list : &buf->order_list);
+	return 0;
+}
+/*------------------------------------------------------------------------------
+ */
+int oz_select_elts_for_tx(struct oz_elt_buf *buf, u8 isoc, unsigned *len,
+		unsigned max_len, struct list_head *list)
+{
+	int count = 0;
+	struct list_head *e;
+	struct list_head *el;
+	struct oz_elt_info *ei;
+	spin_lock_bh(&buf->lock);
+	if (isoc)
+		el = &buf->isoc_list;
+	else
+		el = &buf->order_list;
+	e = el->next;
+	while (e != el) {
+		struct oz_app_hdr *app_hdr;
+		ei = container_of(e, struct oz_elt_info, link_order);
+		e = e->next;
+		if ((*len + ei->length) <= max_len) {
+			app_hdr = (struct oz_app_hdr *)
+				&ei->data[sizeof(struct oz_elt)];
+			app_hdr->elt_seq_num = buf->tx_seq_num[ei->app_id]++;
+			if (buf->tx_seq_num[ei->app_id] == 0)
+				buf->tx_seq_num[ei->app_id] = 1;
+			*len += ei->length;
+			list_del(&ei->link);
+			list_del(&ei->link_order);
+			if (ei->stream) {
+				ei->stream->buf_count -= ei->length;
+				oz_trace2(OZ_TRACE_STREAM,
+					"Stream down: %d  %d\n",
+					ei->stream->buf_count, ei->length);
+				oz_elt_stream_put(ei->stream);
+				ei->stream = 0;
+			}
+			INIT_LIST_HEAD(&ei->link_order);
+			list_add_tail(&ei->link, list);
+			count++;
+		} else {
+			break;
+		}
+	}
+	spin_unlock_bh(&buf->lock);
+	return count;
+}
+/*------------------------------------------------------------------------------
+ */
+int oz_are_elts_available(struct oz_elt_buf *buf)
+{
+	return buf->order_list.next != &buf->order_list;
+}
+/*------------------------------------------------------------------------------
+ */
+void oz_trim_elt_pool(struct oz_elt_buf *buf)
+{
+	struct list_head *free = 0;
+	struct list_head *e;
+	spin_lock_bh(&buf->lock);
+	while (buf->free_elts > buf->max_free_elts) {
+		e = buf->elt_pool;
+		buf->elt_pool = e->next;
+		e->next = free;
+		free = e;
+		buf->free_elts--;
+	}
+	spin_unlock_bh(&buf->lock);
+	while (free) {
+		struct oz_elt_info *ei =
+			container_of(free, struct oz_elt_info, link);
+		free = free->next;
+		oz_free(ei);
+	}
+}