net-caif: add CAIF core protocol stack

CAIF generic protocol implementation. This layer is
somewhat generic in order to be able to use and test it outside
the Linux Kernel.

cfctrl.c     - CAIF control protocol layer
cfdbgl.c     - CAIF debug protocol layer
cfdgml.c     - CAIF datagram protocol layer
cffrml.c     - CAIF framing protocol layer
cfmuxl.c     - CAIF mux protocol layer
cfrfml.c     - CAIF remote file manager protocol layer
cfserl.c     - CAIF serial (fragmentation) protocol layer
cfsrvl.c     - CAIF generic service layer functions
cfutill.c    - CAIF utility protocol layer
cfveil.c     - CAIF AT protocol layer
cfvidl.c     - CAIF video protocol layer

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 664 insertions, 0 deletions

diff --git a/net/caif/cfctrl.c b/net/caif/cfctrl.c
new file mode 100644
index 000000000000..11f80140f3cb
--- /dev/null
+++ b/net/caif/cfctrl.c
@@ -0,0 +1,664 @@
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/stddef.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <net/caif/caif_layer.h>
+#include <net/caif/cfpkt.h>
+#include <net/caif/cfctrl.h>
+
+#define container_obj(layr) container_of(layr, struct cfctrl, serv.layer)
+#define UTILITY_NAME_LENGTH 16
+#define CFPKT_CTRL_PKT_LEN 20
+
+
+#ifdef CAIF_NO_LOOP
+static int handle_loop(struct cfctrl *ctrl,
+			      int cmd, struct cfpkt *pkt){
+	return CAIF_FAILURE;
+}
+#else
+static int handle_loop(struct cfctrl *ctrl,
+		int cmd, struct cfpkt *pkt);
+#endif
+static int cfctrl_recv(struct cflayer *layr, struct cfpkt *pkt);
+static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
+			   int phyid);
+
+
+struct cflayer *cfctrl_create(void)
+{
+	struct cfctrl *this =
+		kmalloc(sizeof(struct cfctrl), GFP_ATOMIC);
+	if (!this) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return NULL;
+	}
+	caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
+	memset(this, 0, sizeof(*this));
+	spin_lock_init(&this->info_list_lock);
+	atomic_set(&this->req_seq_no, 1);
+	atomic_set(&this->rsp_seq_no, 1);
+	this->serv.dev_info.id = 0xff;
+	this->serv.layer.id = 0;
+	this->serv.layer.receive = cfctrl_recv;
+	sprintf(this->serv.layer.name, "ctrl");
+	this->serv.layer.ctrlcmd = cfctrl_ctrlcmd;
+	spin_lock_init(&this->loop_linkid_lock);
+	this->loop_linkid = 1;
+	return &this->serv.layer;
+}
+
+static bool param_eq(struct cfctrl_link_param *p1, struct cfctrl_link_param *p2)
+{
+	bool eq =
+	    p1->linktype == p2->linktype &&
+	    p1->priority == p2->priority &&
+	    p1->phyid == p2->phyid &&
+	    p1->endpoint == p2->endpoint && p1->chtype == p2->chtype;
+
+	if (!eq)
+		return false;
+
+	switch (p1->linktype) {
+	case CFCTRL_SRV_VEI:
+		return true;
+	case CFCTRL_SRV_DATAGRAM:
+		return p1->u.datagram.connid == p2->u.datagram.connid;
+	case CFCTRL_SRV_RFM:
+		return
+		    p1->u.rfm.connid == p2->u.rfm.connid &&
+		    strcmp(p1->u.rfm.volume, p2->u.rfm.volume) == 0;
+	case CFCTRL_SRV_UTIL:
+		return
+		    p1->u.utility.fifosize_kb == p2->u.utility.fifosize_kb
+		    && p1->u.utility.fifosize_bufs ==
+		    p2->u.utility.fifosize_bufs
+		    && strcmp(p1->u.utility.name, p2->u.utility.name) == 0
+		    && p1->u.utility.paramlen == p2->u.utility.paramlen
+		    && memcmp(p1->u.utility.params, p2->u.utility.params,
+			      p1->u.utility.paramlen) == 0;
+
+	case CFCTRL_SRV_VIDEO:
+		return p1->u.video.connid == p2->u.video.connid;
+	case CFCTRL_SRV_DBG:
+		return true;
+	case CFCTRL_SRV_DECM:
+		return false;
+	default:
+		return false;
+	}
+	return false;
+}
+
+bool cfctrl_req_eq(struct cfctrl_request_info *r1,
+		   struct cfctrl_request_info *r2)
+{
+	if (r1->cmd != r2->cmd)
+		return false;
+	if (r1->cmd == CFCTRL_CMD_LINK_SETUP)
+		return param_eq(&r1->param, &r2->param);
+	else
+		return r1->channel_id == r2->channel_id;
+}
+
+/* Insert request at the end */
+void cfctrl_insert_req(struct cfctrl *ctrl,
+			      struct cfctrl_request_info *req)
+{
+	struct cfctrl_request_info *p;
+	spin_lock(&ctrl->info_list_lock);
+	req->next = NULL;
+	atomic_inc(&ctrl->req_seq_no);
+	req->sequence_no = atomic_read(&ctrl->req_seq_no);
+	if (ctrl->first_req == NULL) {
+		ctrl->first_req = req;
+		spin_unlock(&ctrl->info_list_lock);
+		return;
+	}
+	p = ctrl->first_req;
+	while (p->next != NULL)
+		p = p->next;
+	p->next = req;
+	spin_unlock(&ctrl->info_list_lock);
+}
+
+static void cfctrl_insert_req2(struct cfctrl *ctrl, enum cfctrl_cmd cmd,
+			       u8 linkid, struct cflayer *user_layer)
+{
+	struct cfctrl_request_info *req = kmalloc(sizeof(*req), GFP_KERNEL);
+	if (!req) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	req->client_layer = user_layer;
+	req->cmd = cmd;
+	req->channel_id = linkid;
+	cfctrl_insert_req(ctrl, req);
+}
+
+/* Compare and remove request */
+struct cfctrl_request_info *cfctrl_remove_req(struct cfctrl *ctrl,
+					      struct cfctrl_request_info *req)
+{
+	struct cfctrl_request_info *p;
+	struct cfctrl_request_info *ret;
+
+	spin_lock(&ctrl->info_list_lock);
+	if (ctrl->first_req == NULL) {
+		spin_unlock(&ctrl->info_list_lock);
+		return NULL;
+	}
+
+	if (cfctrl_req_eq(req, ctrl->first_req)) {
+		ret = ctrl->first_req;
+		caif_assert(ctrl->first_req);
+		atomic_set(&ctrl->rsp_seq_no,
+				 ctrl->first_req->sequence_no);
+		ctrl->first_req = ctrl->first_req->next;
+		spin_unlock(&ctrl->info_list_lock);
+		return ret;
+	}
+
+	p = ctrl->first_req;
+
+	while (p->next != NULL) {
+		if (cfctrl_req_eq(req, p->next)) {
+			pr_warning("CAIF: %s(): Requests are not "
+					"received in order\n",
+					__func__);
+			ret = p->next;
+			atomic_set(&ctrl->rsp_seq_no,
+					p->next->sequence_no);
+			p->next = p->next->next;
+			spin_unlock(&ctrl->info_list_lock);
+			return ret;
+		}
+		p = p->next;
+	}
+	spin_unlock(&ctrl->info_list_lock);
+
+	pr_warning("CAIF: %s(): Request does not match\n",
+		   __func__);
+	return NULL;
+}
+
+struct cfctrl_rsp *cfctrl_get_respfuncs(struct cflayer *layer)
+{
+	struct cfctrl *this = container_obj(layer);
+	return &this->res;
+}
+
+void cfctrl_set_dnlayer(struct cflayer *this, struct cflayer *dn)
+{
+	this->dn = dn;
+}
+
+void cfctrl_set_uplayer(struct cflayer *this, struct cflayer *up)
+{
+	this->up = up;
+}
+
+static void init_info(struct caif_payload_info *info, struct cfctrl *cfctrl)
+{
+	info->hdr_len = 0;
+	info->channel_id = cfctrl->serv.layer.id;
+	info->dev_info = &cfctrl->serv.dev_info;
+}
+
+void cfctrl_enum_req(struct cflayer *layer, u8 physlinkid)
+{
+	struct cfctrl *cfctrl = container_obj(layer);
+	int ret;
+	struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+	if (!pkt) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	caif_assert(offsetof(struct cfctrl, serv.layer) == 0);
+	init_info(cfpkt_info(pkt), cfctrl);
+	cfpkt_info(pkt)->dev_info->id = physlinkid;
+	cfctrl->serv.dev_info.id = physlinkid;
+	cfpkt_addbdy(pkt, CFCTRL_CMD_ENUM);
+	cfpkt_addbdy(pkt, physlinkid);
+	ret =
+	    cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+	if (ret < 0) {
+		pr_err("CAIF: %s(): Could not transmit enum message\n",
+			__func__);
+		cfpkt_destroy(pkt);
+	}
+}
+
+void cfctrl_linkup_request(struct cflayer *layer,
+			   struct cfctrl_link_param *param,
+			   struct cflayer *user_layer)
+{
+	struct cfctrl *cfctrl = container_obj(layer);
+	u32 tmp32;
+	u16 tmp16;
+	u8 tmp8;
+	struct cfctrl_request_info *req;
+	int ret;
+	char utility_name[16];
+	struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+	if (!pkt) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_SETUP);
+	cfpkt_addbdy(pkt, (param->chtype << 4) + param->linktype);
+	cfpkt_addbdy(pkt, (param->priority << 3) + param->phyid);
+	cfpkt_addbdy(pkt, param->endpoint & 0x03);
+
+	switch (param->linktype) {
+	case CFCTRL_SRV_VEI:
+		break;
+	case CFCTRL_SRV_VIDEO:
+		cfpkt_addbdy(pkt, (u8) param->u.video.connid);
+		break;
+	case CFCTRL_SRV_DBG:
+		break;
+	case CFCTRL_SRV_DATAGRAM:
+		tmp32 = cpu_to_le32(param->u.datagram.connid);
+		cfpkt_add_body(pkt, &tmp32, 4);
+		break;
+	case CFCTRL_SRV_RFM:
+		/* Construct a frame, convert DatagramConnectionID to network
+		 * format long and copy it out...
+		 */
+		tmp32 = cpu_to_le32(param->u.rfm.connid);
+		cfpkt_add_body(pkt, &tmp32, 4);
+		/* Add volume name, including zero termination... */
+		cfpkt_add_body(pkt, param->u.rfm.volume,
+			       strlen(param->u.rfm.volume) + 1);
+		break;
+	case CFCTRL_SRV_UTIL:
+		tmp16 = cpu_to_le16(param->u.utility.fifosize_kb);
+		cfpkt_add_body(pkt, &tmp16, 2);
+		tmp16 = cpu_to_le16(param->u.utility.fifosize_bufs);
+		cfpkt_add_body(pkt, &tmp16, 2);
+		memset(utility_name, 0, sizeof(utility_name));
+		strncpy(utility_name, param->u.utility.name,
+			UTILITY_NAME_LENGTH - 1);
+		cfpkt_add_body(pkt, utility_name, UTILITY_NAME_LENGTH);
+		tmp8 = param->u.utility.paramlen;
+		cfpkt_add_body(pkt, &tmp8, 1);
+		cfpkt_add_body(pkt, param->u.utility.params,
+			       param->u.utility.paramlen);
+		break;
+	default:
+		pr_warning("CAIF: %s():Request setup of bad link type = %d\n",
+			   __func__, param->linktype);
+	}
+	req = kmalloc(sizeof(*req), GFP_KERNEL);
+	if (!req) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	memset(req, 0, sizeof(*req));
+	req->client_layer = user_layer;
+	req->cmd = CFCTRL_CMD_LINK_SETUP;
+	req->param = *param;
+	cfctrl_insert_req(cfctrl, req);
+	init_info(cfpkt_info(pkt), cfctrl);
+	cfpkt_info(pkt)->dev_info->id = param->phyid;
+	ret =
+	    cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+	if (ret < 0) {
+		pr_err("CAIF: %s(): Could not transmit linksetup request\n",
+			__func__);
+		cfpkt_destroy(pkt);
+	}
+}
+
+int cfctrl_linkdown_req(struct cflayer *layer, u8 channelid,
+				struct cflayer *client)
+{
+	int ret;
+	struct cfctrl *cfctrl = container_obj(layer);
+	struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+	if (!pkt) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return -ENOMEM;
+	}
+	cfctrl_insert_req2(cfctrl, CFCTRL_CMD_LINK_DESTROY, channelid, client);
+	cfpkt_addbdy(pkt, CFCTRL_CMD_LINK_DESTROY);
+	cfpkt_addbdy(pkt, channelid);
+	init_info(cfpkt_info(pkt), cfctrl);
+	ret =
+	    cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+	if (ret < 0) {
+		pr_err("CAIF: %s(): Could not transmit link-down request\n",
+			__func__);
+		cfpkt_destroy(pkt);
+	}
+	return ret;
+}
+
+void cfctrl_sleep_req(struct cflayer *layer)
+{
+	int ret;
+	struct cfctrl *cfctrl = container_obj(layer);
+	struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+	if (!pkt) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	cfpkt_addbdy(pkt, CFCTRL_CMD_SLEEP);
+	init_info(cfpkt_info(pkt), cfctrl);
+	ret =
+	    cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+	if (ret < 0)
+		cfpkt_destroy(pkt);
+}
+
+void cfctrl_wake_req(struct cflayer *layer)
+{
+	int ret;
+	struct cfctrl *cfctrl = container_obj(layer);
+	struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+	if (!pkt) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	cfpkt_addbdy(pkt, CFCTRL_CMD_WAKE);
+	init_info(cfpkt_info(pkt), cfctrl);
+	ret =
+	    cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+	if (ret < 0)
+		cfpkt_destroy(pkt);
+}
+
+void cfctrl_getstartreason_req(struct cflayer *layer)
+{
+	int ret;
+	struct cfctrl *cfctrl = container_obj(layer);
+	struct cfpkt *pkt = cfpkt_create(CFPKT_CTRL_PKT_LEN);
+	if (!pkt) {
+		pr_warning("CAIF: %s(): Out of memory\n", __func__);
+		return;
+	}
+	cfpkt_addbdy(pkt, CFCTRL_CMD_START_REASON);
+	init_info(cfpkt_info(pkt), cfctrl);
+	ret =
+	    cfctrl->serv.layer.dn->transmit(cfctrl->serv.layer.dn, pkt);
+	if (ret < 0)
+		cfpkt_destroy(pkt);
+}
+
+
+static int cfctrl_recv(struct cflayer *layer, struct cfpkt *pkt)
+{
+	u8 cmdrsp;
+	u8 cmd;
+	int ret = -1;
+	u16 tmp16;
+	u8 len;
+	u8 param[255];
+	u8 linkid;
+	struct cfctrl *cfctrl = container_obj(layer);
+	struct cfctrl_request_info rsp, *req;
+
+
+	cfpkt_extr_head(pkt, &cmdrsp, 1);
+	cmd = cmdrsp & CFCTRL_CMD_MASK;
+	if (cmd != CFCTRL_CMD_LINK_ERR
+	    && CFCTRL_RSP_BIT != (CFCTRL_RSP_BIT & cmdrsp)) {
+		if (handle_loop(cfctrl, cmd, pkt) == CAIF_FAILURE) {
+			pr_info("CAIF: %s() CAIF Protocol error:"
+				"Response bit not set\n", __func__);
+			goto error;
+		}
+	}
+
+	switch (cmd) {
+	case CFCTRL_CMD_LINK_SETUP:
+		{
+			enum cfctrl_srv serv;
+			enum cfctrl_srv servtype;
+			u8 endpoint;
+			u8 physlinkid;
+			u8 prio;
+			u8 tmp;
+			u32 tmp32;
+			u8 *cp;
+			int i;
+			struct cfctrl_link_param linkparam;
+			memset(&linkparam, 0, sizeof(linkparam));
+
+			cfpkt_extr_head(pkt, &tmp, 1);
+
+			serv = tmp & CFCTRL_SRV_MASK;
+			linkparam.linktype = serv;
+
+			servtype = tmp >> 4;
+			linkparam.chtype = servtype;
+
+			cfpkt_extr_head(pkt, &tmp, 1);
+			physlinkid = tmp & 0x07;
+			prio = tmp >> 3;
+
+			linkparam.priority = prio;
+			linkparam.phyid = physlinkid;
+			cfpkt_extr_head(pkt, &endpoint, 1);
+			linkparam.endpoint = endpoint & 0x03;
+
+			switch (serv) {
+			case CFCTRL_SRV_VEI:
+			case CFCTRL_SRV_DBG:
+				/* Link ID */
+				cfpkt_extr_head(pkt, &linkid, 1);
+				break;
+			case CFCTRL_SRV_VIDEO:
+				cfpkt_extr_head(pkt, &tmp, 1);
+				linkparam.u.video.connid = tmp;
+				/* Link ID */
+				cfpkt_extr_head(pkt, &linkid, 1);
+				break;
+
+			case CFCTRL_SRV_DATAGRAM:
+				cfpkt_extr_head(pkt, &tmp32, 4);
+				linkparam.u.datagram.connid =
+				    le32_to_cpu(tmp32);
+				/* Link ID */
+				cfpkt_extr_head(pkt, &linkid, 1);
+				break;
+			case CFCTRL_SRV_RFM:
+				/* Construct a frame, convert
+				 * DatagramConnectionID
+				 * to network format long and copy it out...
+				 */
+				cfpkt_extr_head(pkt, &tmp32, 4);
+				linkparam.u.rfm.connid =
+				  le32_to_cpu(tmp32);
+				cp = (u8 *) linkparam.u.rfm.volume;
+				for (cfpkt_extr_head(pkt, &tmp, 1);
+				     cfpkt_more(pkt) && tmp != '\0';
+				     cfpkt_extr_head(pkt, &tmp, 1))
+					*cp++ = tmp;
+				*cp = '\0';
+
+				/* Link ID */
+				cfpkt_extr_head(pkt, &linkid, 1);
+
+				break;
+			case CFCTRL_SRV_UTIL:
+				/* Construct a frame, convert
+				 * DatagramConnectionID
+				 * to network format long and copy it out...
+				 */
+				/* Fifosize KB */
+				cfpkt_extr_head(pkt, &tmp16, 2);
+				linkparam.u.utility.fifosize_kb =
+				    le16_to_cpu(tmp16);
+				/* Fifosize bufs */
+				cfpkt_extr_head(pkt, &tmp16, 2);
+				linkparam.u.utility.fifosize_bufs =
+				    le16_to_cpu(tmp16);
+				/* name */
+				cp = (u8 *) linkparam.u.utility.name;
+				caif_assert(sizeof(linkparam.u.utility.name)
+					     >= UTILITY_NAME_LENGTH);
+				for (i = 0;
+				     i < UTILITY_NAME_LENGTH
+				     && cfpkt_more(pkt); i++) {
+					cfpkt_extr_head(pkt, &tmp, 1);
+					*cp++ = tmp;
+				}
+				/* Length */
+				cfpkt_extr_head(pkt, &len, 1);
+				linkparam.u.utility.paramlen = len;
+				/* Param Data */
+				cp = linkparam.u.utility.params;
+				while (cfpkt_more(pkt) && len--) {
+					cfpkt_extr_head(pkt, &tmp, 1);
+					*cp++ = tmp;
+				}
+				/* Link ID */
+				cfpkt_extr_head(pkt, &linkid, 1);
+				/* Length */
+				cfpkt_extr_head(pkt, &len, 1);
+				/* Param Data */
+				cfpkt_extr_head(pkt, &param, len);
+				break;
+			default:
+				pr_warning("CAIF: %s(): Request setup "
+					   "- invalid link type (%d)",
+					   __func__, serv);
+				goto error;
+			}
+
+			rsp.cmd = cmd;
+			rsp.param = linkparam;
+			req = cfctrl_remove_req(cfctrl, &rsp);
+
+			if (CFCTRL_ERR_BIT == (CFCTRL_ERR_BIT & cmdrsp) ||
+				cfpkt_erroneous(pkt)) {
+				pr_err("CAIF: %s(): Invalid O/E bit or parse "
+				       "error on CAIF control channel",
+					__func__);
+				cfctrl->res.reject_rsp(cfctrl->serv.layer.up,
+						       0,
+						       req ? req->client_layer
+						       : NULL);
+			} else {
+				cfctrl->res.linksetup_rsp(cfctrl->serv.
+							  layer.up, linkid,
+							  serv, physlinkid,
+							  req ? req->
+							  client_layer : NULL);
+			}
+
+			if (req != NULL)
+				kfree(req);
+		}
+		break;
+	case CFCTRL_CMD_LINK_DESTROY:
+		cfpkt_extr_head(pkt, &linkid, 1);
+		rsp.cmd = cmd;
+		rsp.channel_id = linkid;
+		req = cfctrl_remove_req(cfctrl, &rsp);
+		cfctrl->res.linkdestroy_rsp(cfctrl->serv.layer.up, linkid,
+					    req ? req->client_layer : NULL);
+		if (req != NULL)
+			kfree(req);
+		break;
+	case CFCTRL_CMD_LINK_ERR:
+		pr_err("CAIF: %s(): Frame Error Indication received\n",
+			__func__);
+		cfctrl->res.linkerror_ind();
+		break;
+	case CFCTRL_CMD_ENUM:
+		cfctrl->res.enum_rsp();
+		break;
+	case CFCTRL_CMD_SLEEP:
+		cfctrl->res.sleep_rsp();
+		break;
+	case CFCTRL_CMD_WAKE:
+		cfctrl->res.wake_rsp();
+		break;
+	case CFCTRL_CMD_LINK_RECONF:
+		cfctrl->res.restart_rsp();
+		break;
+	case CFCTRL_CMD_RADIO_SET:
+		cfctrl->res.radioset_rsp();
+		break;
+	default:
+		pr_err("CAIF: %s(): Unrecognized Control Frame\n", __func__);
+		goto error;
+		break;
+	}
+	ret = 0;
+error:
+	cfpkt_destroy(pkt);
+	return ret;
+}
+
+static void cfctrl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,
+			int phyid)
+{
+	struct cfctrl *this = container_obj(layr);
+	switch (ctrl) {
+	case _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:
+	case CAIF_CTRLCMD_FLOW_OFF_IND:
+		spin_lock(&this->info_list_lock);
+		if (this->first_req != NULL) {
+			pr_warning("CAIF: %s(): Received flow off in "
+				   "control layer", __func__);
+		}
+		spin_unlock(&this->info_list_lock);
+		break;
+	default:
+		break;
+	}
+}
+
+#ifndef CAIF_NO_LOOP
+static int handle_loop(struct cfctrl *ctrl, int cmd, struct cfpkt *pkt)
+{
+	static int last_linkid;
+	u8 linkid, linktype, tmp;
+	switch (cmd) {
+	case CFCTRL_CMD_LINK_SETUP:
+		spin_lock(&ctrl->loop_linkid_lock);
+		for (linkid = last_linkid + 1; linkid < 255; linkid++)
+			if (!ctrl->loop_linkused[linkid])
+				goto found;
+		for (linkid = last_linkid - 1; linkid > 0; linkid--)
+			if (!ctrl->loop_linkused[linkid])
+				goto found;
+		spin_unlock(&ctrl->loop_linkid_lock);
+		return -EINVAL;
+found:
+		if (!ctrl->loop_linkused[linkid])
+			ctrl->loop_linkused[linkid] = 1;
+
+		last_linkid = linkid;
+
+		cfpkt_add_trail(pkt, &linkid, 1);
+		spin_unlock(&ctrl->loop_linkid_lock);
+		cfpkt_peek_head(pkt, &linktype, 1);
+		if (linktype ==  CFCTRL_SRV_UTIL) {
+			tmp = 0x01;
+			cfpkt_add_trail(pkt, &tmp, 1);
+			cfpkt_add_trail(pkt, &tmp, 1);
+		}
+		break;
+
+	case CFCTRL_CMD_LINK_DESTROY:
+		spin_lock(&ctrl->loop_linkid_lock);
+		cfpkt_peek_head(pkt, &linkid, 1);
+		ctrl->loop_linkused[linkid] = 0;
+		spin_unlock(&ctrl->loop_linkid_lock);
+		break;
+	default:
+		break;
+	}
+	return CAIF_SUCCESS;
+}
+#endif