Re: [PATCH] drivers:staging: sources for ST core

[Pavan Savoy <pavan_savoy@ti.com>]

Alan,

I have removed the global reference. Please suggest about the other 2 items, 
1. having device contexts.
All of the data now is held in the tty device context.
What I couldn't do was when a particular protocol registers, like say BT driver registers with this driver via st_register, I couldn't pass the device context. even If I did like the hci device context in that case, 
what use do I make of it ?

2. locking ?
What should be done about locking ?

---
 drivers/staging/ti-st/st_core.c | 1058 +++++++++++++++++++++++++++++++++++++++
 drivers/staging/ti-st/st_core.h |   98 ++++
 2 files changed, 1156 insertions(+), 0 deletions(-)
 create mode 100644 drivers/staging/ti-st/st_core.c
 create mode 100644 drivers/staging/ti-st/st_core.h

diff --git a/drivers/staging/ti-st/st_core.c b/drivers/staging/ti-st/st_core.c
new file mode 100644
index 0000000..cb965b3
--- /dev/null
+++ b/drivers/staging/ti-st/st_core.c
@@ -0,0 +1,1058 @@
+/*
+ *  Shared Transport Line discipline driver Core
+ *	This hooks up ST KIM driver and ST LL driver
+ *  Copyright (C) 2009 Texas Instruments
+ *
+ *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#define pr_fmt(fmt)	"(stc): " fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/tty.h>
+
+/* understand BT, FM and GPS for now */
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/hci.h>
+#include "fm.h"
+/*
+ * packet formats for fm and gps
+ * #include "gps.h"
+ */
+#include "st_core.h"
+#include "st_kim.h"
+#include "st_ll.h"
+#include "st.h"
+
+#ifdef DEBUG
+/* strings to be used for rfkill entries and by
+ * ST Core to be used for sysfs debug entry
+ */
+#define PROTO_ENTRY(type, name)	name
+const unsigned char *protocol_strngs[] = {
+	PROTO_ENTRY(ST_BT, "Bluetooth"),
+	PROTO_ENTRY(ST_FM, "FM"),
+	PROTO_ENTRY(ST_GPS, "GPS"),
+};
+#endif
+
+/********************************************************************/
+#if 0
+/* internal misc functions */
+bool is_protocol_list_empty(void)
+{
+	unsigned char i = 0;
+	pr_info(" %s ", __func__);
+	for (i = 0; i < ST_MAX; i++) {
+		if (st_gdata->list[i] != NULL)
+			return ST_NOTEMPTY;
+		/* not empty */
+	}
+	/* list empty */
+	return ST_EMPTY;
+}
+#endif
+/* can be called in from
+ * -- KIM (during fw download)
+ * -- ST Core (during st_write)
+ *
+ *  This is the internal write function - a wrapper
+ *  to tty->ops->write
+ */
+int st_int_write(struct st_data_s *st_gdata,
+	const unsigned char *data, int count)
+{
+#ifdef VERBOSE			/* for debug */
+	int i;
+#endif
+	struct tty_struct *tty;
+	if (unlikely(st_gdata == NULL || st_gdata->tty == NULL)) {
+		pr_err("tty unavailable to perform write");
+		return ST_ERR_FAILURE;
+	}
+	tty = st_gdata->tty;
+#ifdef VERBOSE
+	printk(KERN_ERR "start data..\n");
+	for (i = 0; i < count; i++)	/* no newlines for each datum */
+		printk(" %x", data[i]);
+	printk(KERN_ERR "\n ..end data\n");
+#endif
+	return tty->ops->write(tty, data, count);
+
+}
+
+/*
+ * push the skb received to relevant
+ * protocol stacks
+ */
+void st_send_frame(enum proto_type protoid, struct st_data_s *st_gdata)
+{
+	pr_info(" %s(prot:%d) ", __func__, protoid);
+
+	if (unlikely
+	    (st_gdata == NULL || st_gdata->rx_skb == NULL
+	     || st_gdata->list[protoid] == NULL)) {
+		pr_err("protocol %d not registered, no data to send?",
+			   protoid);
+		kfree_skb(st_gdata->rx_skb);
+		return;
+	}
+	/* this cannot fail
+	 * this shouldn't take long
+	 * - should be just skb_queue_tail for the
+	 *   protocol stack driver
+	 */
+	if (likely(st_gdata->list[protoid]->recv != NULL)) {
+		if (unlikely(st_gdata->list[protoid]->recv(st_gdata->rx_skb)
+			     != ST_SUCCESS)) {
+			pr_err(" proto stack %d's ->recv failed", protoid);
+			kfree_skb(st_gdata->rx_skb);
+			return;
+		}
+	} else {
+		pr_err(" proto stack %d's ->recv null", protoid);
+		kfree_skb(st_gdata->rx_skb);
+	}
+	pr_info(" done %s", __func__);
+	return;
+}
+
+/*
+ * to call registration complete callbacks
+ * of all protocol stack drivers
+ */
+void st_reg_complete(struct st_data_s *st_gdata, char err)
+{
+	unsigned char i = 0;
+	pr_info(" %s ", __func__);
+	for (i = 0; i < ST_MAX; i++) {
+		if (likely(st_gdata != NULL && st_gdata->list[i] != NULL &&
+			   st_gdata->list[i]->reg_complete_cb != NULL))
+			st_gdata->list[i]->reg_complete_cb(err);
+	}
+}
+
+static inline int st_check_data_len(struct st_data_s *st_gdata,
+	int protoid, int len)
+{
+	register int room = skb_tailroom(st_gdata->rx_skb);
+
+	pr_info("len %d room %d", len, room);
+
+	if (!len) {
+		/* Received packet has only packet header and
+		 * has zero length payload. So, ask ST CORE to
+		 * forward the packet to protocol driver (BT/FM/GPS)
+		 */
+		st_send_frame(protoid, st_gdata);
+
+	} else if (len > room) {
+		/* Received packet's payload length is larger.
+		 * We can't accommodate it in created skb.
+		 */
+		pr_err("Data length is too large len %d room %d", len,
+			   room);
+		kfree_skb(st_gdata->rx_skb);
+	} else {
+		/* Packet header has non-zero payload length and
+		 * we have enough space in created skb. Lets read
+		 * payload data */
+		st_gdata->rx_state = ST_BT_W4_DATA;
+		st_gdata->rx_count = len;
+		return len;
+	}
+
+	/* Change ST state to continue to process next
+	 * packet */
+	st_gdata->rx_state = ST_W4_PACKET_TYPE;
+	st_gdata->rx_skb = NULL;
+	st_gdata->rx_count = 0;
+
+	return 0;
+}
+
+/* internal function for action when wake-up ack
+ * received
+ */
+static inline void st_wakeup_ack(struct st_data_s *st_gdata,
+	unsigned char cmd)
+{
+	register struct sk_buff *waiting_skb;
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	/* de-Q from waitQ and Q in txQ now that the
+	 * chip is awake
+	 */
+	while ((waiting_skb = skb_dequeue(&st_gdata->tx_waitq)))
+		skb_queue_tail(&st_gdata->txq, waiting_skb);
+
+	/* state forwarded to ST LL */
+	st_ll_sleep_state(st_gdata, (unsigned long)cmd);
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+	/* wake up to send the recently copied skbs from waitQ */
+	st_tx_wakeup(st_gdata);
+}
+
+/* Decodes received RAW data and forwards to corresponding
+ * client drivers (Bluetooth,FM,GPS..etc).
+ *
+ */
+void st_int_recv(void *disc_data,
+	const unsigned char *data, long count)
+{
+	register char *ptr;
+	struct hci_event_hdr *eh;
+	struct hci_acl_hdr *ah;
+	struct hci_sco_hdr *sh;
+	struct fm_event_hdr *fm;
+	struct gps_event_hdr *gps;
+	register int len = 0, type = 0, dlen = 0;
+	static enum proto_type protoid = ST_MAX;
+	struct st_data_s *st_gdata = (struct st_data_s *)disc_data;
+
+	ptr = (char *)data;
+	/* tty_receive sent null ? */
+	if (unlikely(ptr == NULL) || (st_gdata == NULL)) {
+		pr_err(" received null from TTY ");
+		return;
+	}
+
+	pr_info("count %ld rx_state %ld"
+		   "rx_count %ld", count, st_gdata->rx_state,
+		   st_gdata->rx_count);
+
+	/* Decode received bytes here */
+	while (count) {
+		if (st_gdata->rx_count) {
+			len = min_t(unsigned int, st_gdata->rx_count, count);
+			memcpy(skb_put(st_gdata->rx_skb, len), ptr, len);
+			st_gdata->rx_count -= len;
+			count -= len;
+			ptr += len;
+
+			if (st_gdata->rx_count)
+				continue;
+
+			/* Check ST RX state machine , where are we? */
+			switch (st_gdata->rx_state) {
+
+				/* Waiting for complete packet ? */
+			case ST_BT_W4_DATA:
+				pr_info("Complete pkt received");
+
+				/* Ask ST CORE to forward
+				 * the packet to protocol driver */
+				st_send_frame(protoid, st_gdata);
+
+				st_gdata->rx_state = ST_W4_PACKET_TYPE;
+				st_gdata->rx_skb = NULL;
+				protoid = ST_MAX;	/* is this required ? */
+				continue;
+
+				/* Waiting for Bluetooth event header ? */
+			case ST_BT_W4_EVENT_HDR:
+				eh = (struct hci_event_hdr *)st_gdata->rx_skb->
+				    data;
+
+				pr_info("Event header: evt 0x%2.2x"
+					   "plen %d", eh->evt, eh->plen);
+
+				st_check_data_len(st_gdata, protoid, eh->plen);
+				continue;
+
+				/* Waiting for Bluetooth acl header ? */
+			case ST_BT_W4_ACL_HDR:
+				ah = (struct hci_acl_hdr *)st_gdata->rx_skb->
+				    data;
+				dlen = __le16_to_cpu(ah->dlen);
+
+				pr_info("ACL header: dlen %d", dlen);
+
+				st_check_data_len(st_gdata, protoid, dlen);
+				continue;
+
+				/* Waiting for Bluetooth sco header ? */
+			case ST_BT_W4_SCO_HDR:
+				sh = (struct hci_sco_hdr *)st_gdata->rx_skb->
+				    data;
+
+				pr_info("SCO header: dlen %d", sh->dlen);
+
+				st_check_data_len(st_gdata, protoid, sh->dlen);
+				continue;
+			case ST_FM_W4_EVENT_HDR:
+				fm = (struct fm_event_hdr *)st_gdata->rx_skb->
+				    data;
+				pr_info("FM Header: ");
+				st_check_data_len(st_gdata, ST_FM, fm->plen);
+				continue;
+				/* TODO : Add GPS packet machine logic here */
+			case ST_GPS_W4_EVENT_HDR:
+				/* [0x09 pkt hdr][R/W byte][2 byte len] */
+				gps = (struct gps_event_hdr *)st_gdata->rx_skb->
+				     data;
+				pr_info("GPS Header: ");
+				st_check_data_len(st_gdata, ST_GPS, gps->plen);
+				continue;
+			}	/* end of switch rx_state */
+		}
+
+		/* end of if rx_count */
+		/* Check first byte of packet and identify module
+		 * owner (BT/FM/GPS) */
+		switch (*ptr) {
+
+			/* Bluetooth event packet? */
+		case HCI_EVENT_PKT:
+			pr_info("Event packet");
+			st_gdata->rx_state = ST_BT_W4_EVENT_HDR;
+			st_gdata->rx_count = HCI_EVENT_HDR_SIZE;
+			type = HCI_EVENT_PKT;
+			protoid = ST_BT;
+			break;
+
+			/* Bluetooth acl packet? */
+		case HCI_ACLDATA_PKT:
+			pr_info("ACL packet");
+			st_gdata->rx_state = ST_BT_W4_ACL_HDR;
+			st_gdata->rx_count = HCI_ACL_HDR_SIZE;
+			type = HCI_ACLDATA_PKT;
+			protoid = ST_BT;
+			break;
+
+			/* Bluetooth sco packet? */
+		case HCI_SCODATA_PKT:
+			pr_info("SCO packet");
+			st_gdata->rx_state = ST_BT_W4_SCO_HDR;
+			st_gdata->rx_count = HCI_SCO_HDR_SIZE;
+			type = HCI_SCODATA_PKT;
+			protoid = ST_BT;
+			break;
+
+			/* Channel 8(FM) packet? */
+		case ST_FM_CH8_PKT:
+			pr_info("FM CH8 packet");
+			type = ST_FM_CH8_PKT;
+			st_gdata->rx_state = ST_FM_W4_EVENT_HDR;
+			st_gdata->rx_count = FM_EVENT_HDR_SIZE;
+			protoid = ST_FM;
+			break;
+
+			/* Channel 9(GPS) packet? */
+		case 0x9:	/*ST_LL_GPS_CH9_PKT */
+			pr_info("GPS CH9 packet");
+			type = 0x9;	/* ST_LL_GPS_CH9_PKT; */
+			protoid = ST_GPS;
+			st_gdata->rx_state = ST_GPS_W4_EVENT_HDR;
+			st_gdata->rx_count = 3;	/* GPS_EVENT_HDR_SIZE -1*/
+			break;
+		case LL_SLEEP_IND:
+		case LL_SLEEP_ACK:
+		case LL_WAKE_UP_IND:
+			pr_info("PM packet");
+			/* this takes appropriate action based on
+			 * sleep state received --
+			 */
+			st_ll_sleep_state(st_gdata, *ptr);
+			ptr++;
+			count--;
+			continue;
+		case LL_WAKE_UP_ACK:
+			pr_info("PM packet");
+			/* wake up ack received */
+			st_wakeup_ack(st_gdata, *ptr);
+			ptr++;
+			count--;
+			continue;
+			/* Unknow packet? */
+		default:
+			pr_err("Unknown packet type %2.2x", (__u8) *ptr);
+			ptr++;
+			count--;
+			continue;
+		};
+		ptr++;
+		count--;
+
+		switch (protoid) {
+		case ST_BT:
+			/* Allocate new packet to hold received data */
+			st_gdata->rx_skb =
+			    bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
+			if (!st_gdata->rx_skb) {
+				pr_err("Can't allocate mem for new packet");
+				st_gdata->rx_state = ST_W4_PACKET_TYPE;
+				st_gdata->rx_count = 0;
+				return;
+			}
+			bt_cb(st_gdata->rx_skb)->pkt_type = type;
+			break;
+		case ST_FM:	/* for FM */
+			st_gdata->rx_skb =
+			    alloc_skb(FM_MAX_FRAME_SIZE, GFP_ATOMIC);
+			if (!st_gdata->rx_skb) {
+				pr_err("Can't allocate mem for new packet");
+				st_gdata->rx_state = ST_W4_PACKET_TYPE;
+				st_gdata->rx_count = 0;
+				return;
+			}
+			/* place holder 0x08 */
+			skb_reserve(st_gdata->rx_skb, 1);
+			st_gdata->rx_skb->cb[0] = ST_FM_CH8_PKT;
+			break;
+		case ST_GPS:
+			/* for GPS */
+			st_gdata->rx_skb =
+			    alloc_skb(100 /*GPS_MAX_FRAME_SIZE */ , GFP_ATOMIC);
+			if (!st_gdata->rx_skb) {
+				pr_err("Can't allocate mem for new packet");
+				st_gdata->rx_state = ST_W4_PACKET_TYPE;
+				st_gdata->rx_count = 0;
+				return;
+			}
+			/* place holder 0x09 */
+			skb_reserve(st_gdata->rx_skb, 1);
+			st_gdata->rx_skb->cb[0] = 0x09;	/*ST_GPS_CH9_PKT; */
+			break;
+		case ST_MAX:
+			break;
+		}
+	}
+	pr_info("done %s", __func__);
+	return;
+}
+
+/* internal de-Q function
+ * -- return previous in-completely written skb
+ *  or return the skb in the txQ
+ */
+struct sk_buff *st_int_dequeue(struct st_data_s *st_gdata)
+{
+	struct sk_buff *returning_skb;
+
+	pr_info("%s", __func__);
+	/* if the previous skb wasn't written completely
+	 */
+	if (st_gdata->tx_skb != NULL) {
+		returning_skb = st_gdata->tx_skb;
+		st_gdata->tx_skb = NULL;
+		return returning_skb;
+	}
+
+	/* de-Q from the txQ always if previous write is complete */
+	return skb_dequeue(&st_gdata->txq);
+}
+
+/* internal Q-ing function
+ * will either Q the skb to txq or the tx_waitq
+ * depending on the ST LL state
+ *
+ * lock the whole func - since ll_getstate and Q-ing should happen
+ * in one-shot
+ */
+void st_int_enqueue(struct st_data_s *st_gdata, struct sk_buff *skb)
+{
+	unsigned long flags = 0;
+
+	pr_info("%s", __func__);
+	/* this function can be invoked in more then one context.
+	 * so have a lock */
+	spin_lock_irqsave(&st_gdata->lock, flags);
+
+	switch (st_ll_getstate(st_gdata)) {
+	case ST_LL_AWAKE:
+		pr_info("ST LL is AWAKE, sending normally");
+		skb_queue_tail(&st_gdata->txq, skb);
+		break;
+	case ST_LL_ASLEEP_TO_AWAKE:
+		skb_queue_tail(&st_gdata->tx_waitq, skb);
+		break;
+	case ST_LL_AWAKE_TO_ASLEEP:	/* host cannot be in this state */
+		pr_err("ST LL is illegal state(%ld),"
+			   "purging received skb.", st_ll_getstate(st_gdata));
+		kfree_skb(skb);
+		break;
+
+	case ST_LL_ASLEEP:
+		/* call a function of ST LL to put data
+		 * in tx_waitQ and wake_ind in txQ
+		 */
+		skb_queue_tail(&st_gdata->tx_waitq, skb);
+		st_ll_wakeup(st_gdata);
+		break;
+	default:
+		pr_err("ST LL is illegal state(%ld),"
+			   "purging received skb.", st_ll_getstate(st_gdata));
+		kfree_skb(skb);
+		break;
+	}
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+	pr_info("done %s", __func__);
+	return;
+}
+
+/*
+ * internal wakeup function
+ * called from either
+ * - TTY layer when write's finished
+ * - st_write (in context of the protocol stack)
+ */
+void st_tx_wakeup(struct st_data_s *st_data)
+{
+	struct sk_buff *skb;
+	unsigned long flags;	/* for irq save flags */
+	pr_info("%s", __func__);
+	/* check for sending & set flag sending here */
+	if (test_and_set_bit(ST_TX_SENDING, &st_data->tx_state)) {
+		pr_info("ST already sending");
+		/* keep sending */
+		set_bit(ST_TX_WAKEUP, &st_data->tx_state);
+		return;
+		/* TX_WAKEUP will be checked in another
+		 * context
+		 */
+	}
+	do {			/* come back if st_tx_wakeup is set */
+		/* woke-up to write */
+		clear_bit(ST_TX_WAKEUP, &st_data->tx_state);
+		while ((skb = st_int_dequeue(st_data))) {
+			int len;
+			spin_lock_irqsave(&st_data->lock, flags);
+			/* enable wake-up from TTY */
+			set_bit(TTY_DO_WRITE_WAKEUP, &st_data->tty->flags);
+			len = st_int_write(st_data, skb->data, skb->len);
+			skb_pull(skb, len);
+			/* if skb->len = len as expected, skb->len=0 */
+			if (skb->len) {
+				/* would be the next skb to be sent */
+				st_data->tx_skb = skb;
+				spin_unlock_irqrestore(&st_data->lock, flags);
+				break;
+			}
+			kfree_skb(skb);
+			spin_unlock_irqrestore(&st_data->lock, flags);
+		}
+		/* if wake-up is set in another context- restart sending */
+	} while (test_bit(ST_TX_WAKEUP, &st_data->tx_state));
+
+	/* clear flag sending */
+	clear_bit(ST_TX_SENDING, &st_data->tx_state);
+}
+
+/********************************************************************/
+/* functions called from ST KIM
+*/
+void kim_st_list_protocols(struct st_data_s *st_gdata, char *buf)
+{
+	unsigned long flags = 0;
+#ifdef DEBUG
+	unsigned char i = ST_MAX;
+#endif
+	spin_lock_irqsave(&st_gdata->lock, flags);
+#ifdef DEBUG			/* more detailed log */
+	for (i = 0; i < ST_MAX; i++) {
+		if (i == 0) {
+			sprintf(buf, "%s is %s", protocol_strngs[i],
+				st_gdata->list[i] !=
+				NULL ? "Registered" : "Unregistered");
+		} else {
+			sprintf(buf, "%s\n%s is %s", buf, protocol_strngs[i],
+				st_gdata->list[i] !=
+				NULL ? "Registered" : "Unregistered");
+		}
+	}
+	sprintf(buf, "%s\n", buf);
+#else /* limited info */
+	sprintf(buf, "BT=%c\nFM=%c\nGPS=%c\n",
+		st_gdata->list[ST_BT] != NULL ? 'R' : 'U',
+		st_gdata->list[ST_FM] != NULL ? 'R' : 'U',
+		st_gdata->list[ST_GPS] != NULL ? 'R' : 'U');
+#endif
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+}
+
+/********************************************************************/
+/*
+ * functions called from protocol stack drivers
+ * to be EXPORT-ed
+ */
+long st_register(struct st_proto_s *new_proto)
+{
+	struct st_data_s	*st_gdata;
+	long err = ST_SUCCESS;
+	unsigned long flags = 0;
+
+	st_kim_ref(&st_gdata);
+	pr_info("%s(%d) ", __func__, new_proto->type);
+	if (st_gdata == NULL || new_proto == NULL || new_proto->recv == NULL
+	    || new_proto->reg_complete_cb == NULL) {
+		pr_err("gdata/new_proto/recv or reg_complete_cb not ready");
+		return ST_ERR_FAILURE;
+	}
+
+	if (new_proto->type < ST_BT || new_proto->type >= ST_MAX) {
+		pr_err("protocol %d not supported", new_proto->type);
+		return ST_ERR_NOPROTO;
+	}
+
+	if (st_gdata->list[new_proto->type] != NULL) {
+		pr_err("protocol %d already registered", new_proto->type);
+		return ST_ERR_ALREADY;
+	}
+
+	/* can be from process context only */
+	spin_lock_irqsave(&st_gdata->lock, flags);
+
+	if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
+		pr_info(" ST_REG_IN_PROGRESS:%d ", new_proto->type);
+		/* fw download in progress */
+		st_kim_chip_toggle(new_proto->type, KIM_GPIO_ACTIVE);
+
+		st_gdata->list[new_proto->type] = new_proto;
+		new_proto->write = st_write;
+
+		set_bit(ST_REG_PENDING, &st_gdata->st_state);
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return ST_ERR_PENDING;
+	} else if (st_gdata->protos_registered == ST_EMPTY) {
+		pr_info(" protocol list empty :%d ", new_proto->type);
+		set_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
+
+		/* release lock previously held - re-locked below */
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+		/* enable the ST LL - to set default chip state */
+		st_ll_enable(st_gdata);
+		/* this may take a while to complete
+		 * since it involves BT fw download
+		 */
+		err = st_kim_start();
+		if (err != ST_SUCCESS) {
+			clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
+			if ((st_gdata->protos_registered != ST_EMPTY) &&
+			    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
+				pr_err(" KIM failure complete callback ");
+				st_reg_complete(st_gdata, ST_ERR_FAILURE);
+			}
+
+			return ST_ERR_FAILURE;
+		}
+
+		/* the protocol might require other gpios to be toggled
+		 */
+		st_kim_chip_toggle(new_proto->type, KIM_GPIO_ACTIVE);
+		clear_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state);
+
+		/* this is where all pending registration
+		 * are signalled to be complete by calling callback functions
+		 */
+		if ((st_gdata->protos_registered != ST_EMPTY) &&
+		    (test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
+			pr_info(" call reg complete callback ");
+			st_gdata->protos_registered++;
+			st_reg_complete(st_gdata, ST_SUCCESS);
+		}
+		clear_bit(ST_REG_PENDING, &st_gdata->st_state);
+
+		/* check for already registered once more,
+		 * since the above check is old
+		 */
+		if (st_gdata->list[new_proto->type] != NULL) {
+			pr_err(" proto %d already registered ",
+				   new_proto->type);
+			return ST_ERR_ALREADY;
+		}
+
+		spin_lock_irqsave(&st_gdata->lock, flags);
+		st_gdata->list[new_proto->type] = new_proto;
+		new_proto->write = st_write;
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return err;
+	}
+	/* if fw is already downloaded & new stack registers protocol */
+	else {
+		switch (new_proto->type) {
+		case ST_BT:
+			/* do nothing */
+			break;
+		case ST_FM:
+		case ST_GPS:
+			st_kim_chip_toggle(new_proto->type, KIM_GPIO_ACTIVE);
+			break;
+		case ST_MAX:
+		default:
+			pr_err("%d protocol not supported",
+				   new_proto->type);
+			err = ST_ERR_NOPROTO;
+			/* something wrong */
+			break;
+		}
+		st_gdata->list[new_proto->type] = new_proto;
+		new_proto->write = st_write;
+
+		/* lock already held before entering else */
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return err;
+	}
+	pr_info("done %s(%d) ", __func__, new_proto->type);
+}
+EXPORT_SYMBOL_GPL(st_register);
+
+/* to unregister a protocol -
+ * to be called from protocol stack driver
+ */
+long st_unregister(enum proto_type type)
+{
+	long err = ST_SUCCESS;
+	unsigned long flags = 0;
+	struct st_data_s	*st_gdata;
+
+	pr_info("%s: %d ", __func__, type);
+
+	st_kim_ref(&st_gdata);
+	if (type < ST_BT || type >= ST_MAX) {
+		pr_err(" protocol %d not supported", type);
+		return ST_ERR_NOPROTO;
+	}
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+
+	if (st_gdata->list[type] == NULL) {
+		pr_err(" protocol %d not registered", type);
+		spin_unlock_irqrestore(&st_gdata->lock, flags);
+		return ST_ERR_NOPROTO;
+	}
+
+	st_gdata->protos_registered--;
+	st_gdata->list[type] = NULL;
+
+	/* kim ignores BT in the below function
+	 * and handles the rest, BT is toggled
+	 * only in kim_start and kim_stop
+	 */
+	st_kim_chip_toggle(type, KIM_GPIO_INACTIVE);
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+	if ((st_gdata->protos_registered == ST_EMPTY) &&
+	    (!test_bit(ST_REG_PENDING, &st_gdata->st_state))) {
+		pr_info(" all protocols unregistered ");
+
+		/* stop traffic on tty */
+		if (st_gdata->tty) {
+			tty_ldisc_flush(st_gdata->tty);
+			stop_tty(st_gdata->tty);
+		}
+
+		/* all protocols now unregistered */
+		st_kim_stop();
+		/* disable ST LL */
+		st_ll_disable(st_gdata);
+	}
+	return err;
+}
+
+/*
+ * called in protocol stack drivers
+ * via the write function pointer
+ */
+long st_write(struct sk_buff *skb)
+{
+	struct st_data_s *st_gdata;
+#ifdef DEBUG
+	enum proto_type protoid = ST_MAX;
+#endif
+	long len;
+
+	st_kim_ref(&st_gdata);
+	if (unlikely(skb == NULL || st_gdata == NULL
+		|| st_gdata->tty == NULL)) {
+		pr_err("data/tty unavailable to perform write");
+		return ST_ERR_FAILURE;
+	}
+#ifdef DEBUG			/* open-up skb to read the 1st byte */
+	switch (skb->data[0]) {
+	case HCI_COMMAND_PKT:
+	case HCI_ACLDATA_PKT:
+	case HCI_SCODATA_PKT:
+		protoid = ST_BT;
+		break;
+	case ST_FM_CH8_PKT:
+		protoid = ST_FM;
+		break;
+	case 0x09:
+		protoid = ST_GPS;
+		break;
+	}
+	if (unlikely(st_gdata->list[protoid] == NULL)) {
+		pr_err(" protocol %d not registered, and writing? ",
+			   protoid);
+		return ST_ERR_FAILURE;
+	}
+#endif
+	pr_info("%d to be written", skb->len);
+	len = skb->len;
+
+	/* st_ll to decide where to enqueue the skb */
+	st_int_enqueue(st_gdata, skb);
+	/* wake up */
+	st_tx_wakeup(st_gdata);
+
+	/* return number of bytes written */
+	return len;
+}
+
+/* for protocols making use of shared transport */
+EXPORT_SYMBOL_GPL(st_unregister);
+
+/********************************************************************/
+/*
+ * functions called from TTY layer
+ */
+static int st_tty_open(struct tty_struct *tty)
+{
+	int err = ST_SUCCESS;
+	struct st_data_s *st_gdata;
+	pr_info("%s ", __func__);
+
+	st_kim_ref(&st_gdata);
+	st_gdata->tty = tty;
+	tty->disc_data = st_gdata;
+
+	/* don't do an wakeup for now */
+	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
+	/* mem already allocated
+	 */
+	tty->receive_room = 65536;
+	/* Flush any pending characters in the driver and discipline. */
+	tty_ldisc_flush(tty);
+	tty_driver_flush_buffer(tty);
+	/*
+	 * signal to UIM via KIM that -
+	 * installation of N_TI_WL ldisc is complete
+	 */
+	st_kim_complete();
+	pr_info("done %s", __func__);
+	return err;
+}
+
+static void st_tty_close(struct tty_struct *tty)
+{
+	unsigned char i = ST_MAX;
+	unsigned long flags = 0;
+	struct	st_data_s *st_gdata = tty->disc_data;
+
+	pr_info("%s ", __func__);
+
+	/* TODO:
+	 * if a protocol has been registered & line discipline
+	 * un-installed for some reason - what should be done ?
+	 */
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	for (i = ST_BT; i < ST_MAX; i++) {
+		if (st_gdata->list[i] != NULL)
+			pr_err("%d not un-registered", i);
+		st_gdata->list[i] = NULL;
+	}
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+	/*
+	 * signal to UIM via KIM that -
+	 * N_TI_WL ldisc is un-installed
+	 */
+	st_kim_complete();
+	st_gdata->tty = NULL;
+	/* Flush any pending characters in the driver and discipline. */
+	tty_ldisc_flush(tty);
+	tty_driver_flush_buffer(tty);
+
+	spin_lock_irqsave(&st_gdata->lock, flags);
+	/* empty out txq and tx_waitq */
+	skb_queue_purge(&st_gdata->txq);
+	skb_queue_purge(&st_gdata->tx_waitq);
+	/* reset the TTY Rx states of ST */
+	st_gdata->rx_count = 0;
+	st_gdata->rx_state = ST_W4_PACKET_TYPE;
+	kfree_skb(st_gdata->rx_skb);
+	st_gdata->rx_skb = NULL;
+	spin_unlock_irqrestore(&st_gdata->lock, flags);
+
+	pr_info("%s: done ", __func__);
+}
+
+static void st_tty_receive(struct tty_struct *tty, const unsigned char *data,
+			   char *tty_flags, int count)
+{
+	struct st_data_s *st_gdata = tty->disc_data;
+#ifdef VERBOSE
+	long i;
+	printk(KERN_ERR "incoming data...\n");
+	for (i = 0; i < count; i++)
+		printk(" %x", data[i]);
+	printk(KERN_ERR "\n.. data end\n");
+#endif
+
+	if (test_bit(ST_REG_IN_PROGRESS, &st_gdata->st_state)) {
+		/*
+		 * if fw download is in progress then route incoming data
+		 * to KIM for validation
+		 */
+		st_kim_recv(st_gdata, data, count);
+	} else {
+		st_int_recv(st_gdata, data, count);
+	}
+	pr_info("done %s", __func__);
+}
+
+/* wake-up function called in from the TTY layer
+ * inside the internal wakeup function will be called
+ */
+static void st_tty_wakeup(struct tty_struct *tty)
+{
+	struct	st_data_s *st_gdata = tty->disc_data;
+	pr_info("%s ", __func__);
+	/* don't do an wakeup for now */
+	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
+	/* call our internal wakeup */
+	st_tx_wakeup((void *)st_gdata);
+}
+
+static void st_tty_flush_buffer(struct tty_struct *tty)
+{
+	struct	st_data_s *st_gdata = tty->disc_data;
+	pr_info("%s ", __func__);
+
+	kfree_skb(st_gdata->tx_skb);
+	st_gdata->tx_skb = NULL;
+
+	tty->ops->flush_buffer(tty);
+	return;
+}
+
+/********************************************************************/
+int st_core_init(struct st_data_s **core_data)
+{
+	struct st_data_s *st_gdata;
+	long err;
+	static struct tty_ldisc_ops *st_ldisc_ops;
+
+	/* populate and register to TTY line discipline */
+	st_ldisc_ops = kzalloc(sizeof(*st_ldisc_ops), GFP_KERNEL);
+	if (!st_ldisc_ops) {
+		pr_err("no mem to allocate");
+		return -ENOMEM;
+	}
+
+	st_ldisc_ops->magic = TTY_LDISC_MAGIC;
+	st_ldisc_ops->name = "n_st";	/*"n_hci"; */
+	st_ldisc_ops->open = st_tty_open;
+	st_ldisc_ops->close = st_tty_close;
+	st_ldisc_ops->receive_buf = st_tty_receive;
+	st_ldisc_ops->write_wakeup = st_tty_wakeup;
+	st_ldisc_ops->flush_buffer = st_tty_flush_buffer;
+	st_ldisc_ops->owner = THIS_MODULE;
+
+	err = tty_register_ldisc(N_TI_WL, st_ldisc_ops);
+	if (err) {
+		pr_err("error registering %d line discipline %ld",
+			   N_TI_WL, err);
+		kfree(st_ldisc_ops);
+		return err;
+	}
+	pr_info("registered n_shared line discipline");
+
+	st_gdata = kzalloc(sizeof(struct st_data_s), GFP_KERNEL);
+	if (!st_gdata) {
+		pr_err("memory allocation failed");
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc %ld", err);
+		kfree(st_ldisc_ops);
+		err = -ENOMEM;
+		return err;
+	}
+
+	/* Initialize ST TxQ and Tx waitQ queue head. All BT/FM/GPS module skb's
+	 * will be pushed in this queue for actual transmission.
+	 */
+	skb_queue_head_init(&st_gdata->txq);
+	skb_queue_head_init(&st_gdata->tx_waitq);
+
+	/* Locking used in st_int_enqueue() to avoid multiple execution */
+	spin_lock_init(&st_gdata->lock);
+
+	/* ldisc_ops ref to be only used in __exit of module */
+	st_gdata->ldisc_ops = st_ldisc_ops;
+
+#if 0
+	err = st_kim_init();
+	if (err) {
+		pr_err("error during kim initialization(%ld)", err);
+		kfree(st_gdata);
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc");
+		kfree(st_ldisc_ops);
+		return -1;
+	}
+#endif
+
+	err = st_ll_init(st_gdata);
+	if (err) {
+		pr_err("error during st_ll initialization(%ld)", err);
+		kfree(st_gdata);
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc");
+		kfree(st_ldisc_ops);
+		return -1;
+	}
+	*core_data = st_gdata;
+	return 0;
+}
+
+void st_core_exit(struct st_data_s *st_gdata)
+{
+	long err;
+	/* internal module cleanup */
+	err = st_ll_deinit(st_gdata);
+	if (err)
+		pr_err("error during deinit of ST LL %ld", err);
+#if 0
+	err = st_kim_deinit();
+	if (err)
+		pr_err("error during deinit of ST KIM %ld", err);
+#endif
+	if (st_gdata != NULL) {
+		/* Free ST Tx Qs and skbs */
+		skb_queue_purge(&st_gdata->txq);
+		skb_queue_purge(&st_gdata->tx_waitq);
+		kfree_skb(st_gdata->rx_skb);
+		kfree_skb(st_gdata->tx_skb);
+		/* TTY ldisc cleanup */
+		err = tty_unregister_ldisc(N_TI_WL);
+		if (err)
+			pr_err("unable to un-register ldisc %ld", err);
+		kfree(st_gdata->ldisc_ops);
+		/* free the global data pointer */
+		kfree(st_gdata);
+	}
+}
+
+
diff --git a/drivers/staging/ti-st/st_core.h b/drivers/staging/ti-st/st_core.h
new file mode 100644
index 0000000..f271c88
--- /dev/null
+++ b/drivers/staging/ti-st/st_core.h
@@ -0,0 +1,98 @@
+/*
+ *  Shared Transport Core header file
+ *
+ *  Copyright (C) 2009 Texas Instruments
+ *
+ *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#ifndef ST_CORE_H
+#define ST_CORE_H
+
+#include <linux/skbuff.h>
+#include "st.h"
+
+/* states of protocol list */
+#define ST_NOTEMPTY	1
+#define ST_EMPTY	0
+
+/*
+ * possible st_states
+ */
+#define ST_INITIALIZING		1
+#define ST_REG_IN_PROGRESS	2
+#define ST_REG_PENDING		3
+#define ST_WAITING_FOR_RESP	4
+
+/*
+ * local data required for ST/KIM/ST-HCI-LL
+ */
+struct st_data_s {
+	unsigned long st_state;
+/*
+ * an instance of tty_struct & ldisc ops to move around
+ */
+	struct tty_struct *tty;
+	struct tty_ldisc_ops *ldisc_ops;
+/*
+ * the tx skb -
+ * if the skb is already dequeued and the tty failed to write the same
+ * maintain the skb to write in the next transaction
+ */
+	struct sk_buff *tx_skb;
+#define ST_TX_SENDING	1
+#define ST_TX_WAKEUP	2
+	unsigned long tx_state;
+/*
+ * list of protocol registered
+ */
+	struct st_proto_s *list[ST_MAX];
+/*
+ * lock
+ */
+	unsigned long rx_state;
+	unsigned long rx_count;
+	struct sk_buff *rx_skb;
+	struct sk_buff_head txq, tx_waitq;
+	spinlock_t lock;	/* ST LL state lock  */
+	unsigned char	protos_registered;
+	unsigned long ll_state;	/* ST LL power state */
+};
+
+/* point this to tty->driver->write or tty->ops->write
+ * depending upon the kernel version
+ */
+int st_int_write(struct st_data_s*, const unsigned char*, int);
+/* internal write function, passed onto protocol drivers
+ * via the write function ptr of protocol struct
+ */
+long st_write(struct sk_buff *);
+/* function to be called from ST-LL
+ */
+void st_ll_send_frame(enum proto_type, struct sk_buff *);
+/* internal wake up function */
+void st_tx_wakeup(struct st_data_s *st_data);
+
+int st_core_init(struct st_data_s **);
+void st_core_exit(struct st_data_s *);
+void st_kim_ref(struct st_data_s **);
+
+#define GPS_STUB_TEST
+#ifdef GPS_STUB_TEST
+int gps_chrdrv_stub_write(const unsigned char*, int);
+void gps_chrdrv_stub_init(void);
+#endif
+
+#endif /*ST_CORE_H */
-- 
1.5.4.3