5 files changed, 2315 insertions, 0 deletions

diff --git a/drivers/hsi/clients/Kconfig b/drivers/hsi/clients/Kconfig
new file mode 100644
index 00000000000..bc60dec3f58
--- /dev/null
+++ b/drivers/hsi/clients/Kconfig
@@ -0,0 +1,30 @@
+#
+# HSI clients configuration
+#
+
+comment "HSI clients"
+
+config NOKIA_MODEM
+	tristate "Nokia Modem"
+	depends on HSI && SSI_PROTOCOL
+	help
+	Say Y here if you want to add support for the modem on Nokia
+	N900 (Nokia RX-51) hardware.
+
+	If unsure, say N.
+
+config SSI_PROTOCOL
+	tristate "SSI protocol"
+	depends on HSI && PHONET && OMAP_SSI
+	help
+	If you say Y here, you will enable the SSI protocol aka McSAAB.
+
+	If unsure, say N.
+
+config HSI_CHAR
+	tristate "HSI/SSI character driver"
+	depends on HSI
+	---help---
+	  If you say Y here, you will enable the HSI/SSI character driver.
+	  This driver provides a simple character device interface for
+	  serial communication with the cellular modem over HSI/SSI bus.
diff --git a/drivers/hsi/clients/Makefile b/drivers/hsi/clients/Makefile
new file mode 100644
index 00000000000..4d5bc0e0b27
--- /dev/null
+++ b/drivers/hsi/clients/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for HSI clients
+#
+
+obj-$(CONFIG_NOKIA_MODEM)	+= nokia-modem.o
+obj-$(CONFIG_SSI_PROTOCOL)	+= ssi_protocol.o
+obj-$(CONFIG_HSI_CHAR)		+= hsi_char.o
diff --git a/drivers/hsi/clients/hsi_char.c b/drivers/hsi/clients/hsi_char.c
new file mode 100644
index 00000000000..57f70c28fa3
--- /dev/null
+++ b/drivers/hsi/clients/hsi_char.c
@@ -0,0 +1,802 @@
+/*
+ * HSI character device driver, implements the character device
+ * interface.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ *
+ * Contact: Andras Domokos <andras.domokos@nokia.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/kmemleak.h>
+#include <linux/ioctl.h>
+#include <linux/wait.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/uaccess.h>
+#include <linux/scatterlist.h>
+#include <linux/stat.h>
+#include <linux/hsi/hsi.h>
+#include <linux/hsi/hsi_char.h>
+
+#define HSC_DEVS		16 /* Num of channels */
+#define HSC_MSGS		4
+
+#define HSC_RXBREAK		0
+
+#define HSC_ID_BITS		6
+#define HSC_PORT_ID_BITS	4
+#define HSC_ID_MASK		3
+#define HSC_PORT_ID_MASK	3
+#define HSC_CH_MASK		0xf
+
+/*
+ * We support up to 4 controllers that can have up to 4
+ * ports, which should currently be more than enough.
+ */
+#define HSC_BASEMINOR(id, port_id) \
+		((((id) & HSC_ID_MASK) << HSC_ID_BITS) | \
+		(((port_id) & HSC_PORT_ID_MASK) << HSC_PORT_ID_BITS))
+
+enum {
+	HSC_CH_OPEN,
+	HSC_CH_READ,
+	HSC_CH_WRITE,
+	HSC_CH_WLINE,
+};
+
+enum {
+	HSC_RX,
+	HSC_TX,
+};
+
+struct hsc_client_data;
+/**
+ * struct hsc_channel - hsi_char internal channel data
+ * @ch: channel number
+ * @flags: Keeps state of the channel (open/close, reading, writing)
+ * @free_msgs_list: List of free HSI messages/requests
+ * @rx_msgs_queue: List of pending RX requests
+ * @tx_msgs_queue: List of pending TX requests
+ * @lock: Serialize access to the lists
+ * @cl: reference to the associated hsi_client
+ * @cl_data: reference to the client data that this channels belongs to
+ * @rx_wait: RX requests wait queue
+ * @tx_wait: TX requests wait queue
+ */
+struct hsc_channel {
+	unsigned int		ch;
+	unsigned long		flags;
+	struct list_head	free_msgs_list;
+	struct list_head	rx_msgs_queue;
+	struct list_head	tx_msgs_queue;
+	spinlock_t		lock;
+	struct hsi_client	*cl;
+	struct hsc_client_data *cl_data;
+	wait_queue_head_t	rx_wait;
+	wait_queue_head_t	tx_wait;
+};
+
+/**
+ * struct hsc_client_data - hsi_char internal client data
+ * @cdev: Characther device associated to the hsi_client
+ * @lock: Lock to serialize open/close access
+ * @flags: Keeps track of port state (rx hwbreak armed)
+ * @usecnt: Use count for claiming the HSI port (mutex protected)
+ * @cl: Referece to the HSI client
+ * @channels: Array of channels accessible by the client
+ */
+struct hsc_client_data {
+	struct cdev		cdev;
+	struct mutex		lock;
+	unsigned long		flags;
+	unsigned int		usecnt;
+	struct hsi_client	*cl;
+	struct hsc_channel	channels[HSC_DEVS];
+};
+
+/* Stores the major number dynamically allocated for hsi_char */
+static unsigned int hsc_major;
+/* Maximum buffer size that hsi_char will accept from userspace */
+static unsigned int max_data_size = 0x1000;
+module_param(max_data_size, uint, 0);
+MODULE_PARM_DESC(max_data_size, "max read/write data size [4,8..65536] (^2)");
+
+static void hsc_add_tail(struct hsc_channel *channel, struct hsi_msg *msg,
+							struct list_head *queue)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->lock, flags);
+	list_add_tail(&msg->link, queue);
+	spin_unlock_irqrestore(&channel->lock, flags);
+}
+
+static struct hsi_msg *hsc_get_first_msg(struct hsc_channel *channel,
+							struct list_head *queue)
+{
+	struct hsi_msg *msg = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->lock, flags);
+
+	if (list_empty(queue))
+		goto out;
+
+	msg = list_first_entry(queue, struct hsi_msg, link);
+	list_del(&msg->link);
+out:
+	spin_unlock_irqrestore(&channel->lock, flags);
+
+	return msg;
+}
+
+static inline void hsc_msg_free(struct hsi_msg *msg)
+{
+	kfree(sg_virt(msg->sgt.sgl));
+	hsi_free_msg(msg);
+}
+
+static void hsc_free_list(struct list_head *list)
+{
+	struct hsi_msg *msg, *tmp;
+
+	list_for_each_entry_safe(msg, tmp, list, link) {
+		list_del(&msg->link);
+		hsc_msg_free(msg);
+	}
+}
+
+static void hsc_reset_list(struct hsc_channel *channel, struct list_head *l)
+{
+	unsigned long flags;
+	LIST_HEAD(list);
+
+	spin_lock_irqsave(&channel->lock, flags);
+	list_splice_init(l, &list);
+	spin_unlock_irqrestore(&channel->lock, flags);
+
+	hsc_free_list(&list);
+}
+
+static inline struct hsi_msg *hsc_msg_alloc(unsigned int alloc_size)
+{
+	struct hsi_msg *msg;
+	void *buf;
+
+	msg = hsi_alloc_msg(1, GFP_KERNEL);
+	if (!msg)
+		goto out;
+	buf = kmalloc(alloc_size, GFP_KERNEL);
+	if (!buf) {
+		hsi_free_msg(msg);
+		goto out;
+	}
+	sg_init_one(msg->sgt.sgl, buf, alloc_size);
+	/* Ignore false positive, due to sg pointer handling */
+	kmemleak_ignore(buf);
+
+	return msg;
+out:
+	return NULL;
+}
+
+static inline int hsc_msgs_alloc(struct hsc_channel *channel)
+{
+	struct hsi_msg *msg;
+	int i;
+
+	for (i = 0; i < HSC_MSGS; i++) {
+		msg = hsc_msg_alloc(max_data_size);
+		if (!msg)
+			goto out;
+		msg->channel = channel->ch;
+		list_add_tail(&msg->link, &channel->free_msgs_list);
+	}
+
+	return 0;
+out:
+	hsc_free_list(&channel->free_msgs_list);
+
+	return -ENOMEM;
+}
+
+static inline unsigned int hsc_msg_len_get(struct hsi_msg *msg)
+{
+	return msg->sgt.sgl->length;
+}
+
+static inline void hsc_msg_len_set(struct hsi_msg *msg, unsigned int len)
+{
+	msg->sgt.sgl->length = len;
+}
+
+static void hsc_rx_completed(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+	struct hsc_channel *channel = cl_data->channels + msg->channel;
+
+	if (test_bit(HSC_CH_READ, &channel->flags)) {
+		hsc_add_tail(channel, msg, &channel->rx_msgs_queue);
+		wake_up(&channel->rx_wait);
+	} else {
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+}
+
+static void hsc_rx_msg_destructor(struct hsi_msg *msg)
+{
+	msg->status = HSI_STATUS_ERROR;
+	hsc_msg_len_set(msg, 0);
+	hsc_rx_completed(msg);
+}
+
+static void hsc_tx_completed(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+	struct hsc_channel *channel = cl_data->channels + msg->channel;
+
+	if (test_bit(HSC_CH_WRITE, &channel->flags)) {
+		hsc_add_tail(channel, msg, &channel->tx_msgs_queue);
+		wake_up(&channel->tx_wait);
+	} else {
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+}
+
+static void hsc_tx_msg_destructor(struct hsi_msg *msg)
+{
+	msg->status = HSI_STATUS_ERROR;
+	hsc_msg_len_set(msg, 0);
+	hsc_tx_completed(msg);
+}
+
+static void hsc_break_req_destructor(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+
+	hsi_free_msg(msg);
+	clear_bit(HSC_RXBREAK, &cl_data->flags);
+}
+
+static void hsc_break_received(struct hsi_msg *msg)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(msg->cl);
+	struct hsc_channel *channel = cl_data->channels;
+	int i, ret;
+
+	/* Broadcast HWBREAK on all channels */
+	for (i = 0; i < HSC_DEVS; i++, channel++) {
+		struct hsi_msg *msg2;
+
+		if (!test_bit(HSC_CH_READ, &channel->flags))
+			continue;
+		msg2 = hsc_get_first_msg(channel, &channel->free_msgs_list);
+		if (!msg2)
+			continue;
+		clear_bit(HSC_CH_READ, &channel->flags);
+		hsc_msg_len_set(msg2, 0);
+		msg2->status = HSI_STATUS_COMPLETED;
+		hsc_add_tail(channel, msg2, &channel->rx_msgs_queue);
+		wake_up(&channel->rx_wait);
+	}
+	hsi_flush(msg->cl);
+	ret = hsi_async_read(msg->cl, msg);
+	if (ret < 0)
+		hsc_break_req_destructor(msg);
+}
+
+static int hsc_break_request(struct hsi_client *cl)
+{
+	struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+	int ret;
+
+	if (test_and_set_bit(HSC_RXBREAK, &cl_data->flags))
+		return -EBUSY;
+
+	msg = hsi_alloc_msg(0, GFP_KERNEL);
+	if (!msg) {
+		clear_bit(HSC_RXBREAK, &cl_data->flags);
+		return -ENOMEM;
+	}
+	msg->break_frame = 1;
+	msg->complete = hsc_break_received;
+	msg->destructor = hsc_break_req_destructor;
+	ret = hsi_async_read(cl, msg);
+	if (ret < 0)
+		hsc_break_req_destructor(msg);
+
+	return ret;
+}
+
+static int hsc_break_send(struct hsi_client *cl)
+{
+	struct hsi_msg *msg;
+	int ret;
+
+	msg = hsi_alloc_msg(0, GFP_ATOMIC);
+	if (!msg)
+		return -ENOMEM;
+	msg->break_frame = 1;
+	msg->complete = hsi_free_msg;
+	msg->destructor = hsi_free_msg;
+	ret = hsi_async_write(cl, msg);
+	if (ret < 0)
+		hsi_free_msg(msg);
+
+	return ret;
+}
+
+static int hsc_rx_set(struct hsi_client *cl, struct hsc_rx_config *rxc)
+{
+	struct hsi_config tmp;
+	int ret;
+
+	if ((rxc->mode != HSI_MODE_STREAM) && (rxc->mode != HSI_MODE_FRAME))
+		return -EINVAL;
+	if ((rxc->channels == 0) || (rxc->channels > HSC_DEVS))
+		return -EINVAL;
+	if (rxc->channels & (rxc->channels - 1))
+		return -EINVAL;
+	if ((rxc->flow != HSI_FLOW_SYNC) && (rxc->flow != HSI_FLOW_PIPE))
+		return -EINVAL;
+	tmp = cl->rx_cfg;
+	cl->rx_cfg.mode = rxc->mode;
+	cl->rx_cfg.num_hw_channels = rxc->channels;
+	cl->rx_cfg.flow = rxc->flow;
+	ret = hsi_setup(cl);
+	if (ret < 0) {
+		cl->rx_cfg = tmp;
+		return ret;
+	}
+	if (rxc->mode == HSI_MODE_FRAME)
+		hsc_break_request(cl);
+
+	return ret;
+}
+
+static inline void hsc_rx_get(struct hsi_client *cl, struct hsc_rx_config *rxc)
+{
+	rxc->mode = cl->rx_cfg.mode;
+	rxc->channels = cl->rx_cfg.num_hw_channels;
+	rxc->flow = cl->rx_cfg.flow;
+}
+
+static int hsc_tx_set(struct hsi_client *cl, struct hsc_tx_config *txc)
+{
+	struct hsi_config tmp;
+	int ret;
+
+	if ((txc->mode != HSI_MODE_STREAM) && (txc->mode != HSI_MODE_FRAME))
+		return -EINVAL;
+	if ((txc->channels == 0) || (txc->channels > HSC_DEVS))
+		return -EINVAL;
+	if (txc->channels & (txc->channels - 1))
+		return -EINVAL;
+	if ((txc->arb_mode != HSI_ARB_RR) && (txc->arb_mode != HSI_ARB_PRIO))
+		return -EINVAL;
+	tmp = cl->tx_cfg;
+	cl->tx_cfg.mode = txc->mode;
+	cl->tx_cfg.num_hw_channels = txc->channels;
+	cl->tx_cfg.speed = txc->speed;
+	cl->tx_cfg.arb_mode = txc->arb_mode;
+	ret = hsi_setup(cl);
+	if (ret < 0) {
+		cl->tx_cfg = tmp;
+		return ret;
+	}
+
+	return ret;
+}
+
+static inline void hsc_tx_get(struct hsi_client *cl, struct hsc_tx_config *txc)
+{
+	txc->mode = cl->tx_cfg.mode;
+	txc->channels = cl->tx_cfg.num_hw_channels;
+	txc->speed = cl->tx_cfg.speed;
+	txc->arb_mode = cl->tx_cfg.arb_mode;
+}
+
+static ssize_t hsc_read(struct file *file, char __user *buf, size_t len,
+						loff_t *ppos __maybe_unused)
+{
+	struct hsc_channel *channel = file->private_data;
+	struct hsi_msg *msg;
+	ssize_t ret;
+
+	if (len == 0)
+		return 0;
+	if (!IS_ALIGNED(len, sizeof(u32)))
+		return -EINVAL;
+	if (len > max_data_size)
+		len = max_data_size;
+	if (channel->ch >= channel->cl->rx_cfg.num_hw_channels)
+		return -ECHRNG;
+	if (test_and_set_bit(HSC_CH_READ, &channel->flags))
+		return -EBUSY;
+	msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
+	if (!msg) {
+		ret = -ENOSPC;
+		goto out;
+	}
+	hsc_msg_len_set(msg, len);
+	msg->complete = hsc_rx_completed;
+	msg->destructor = hsc_rx_msg_destructor;
+	ret = hsi_async_read(channel->cl, msg);
+	if (ret < 0) {
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+		goto out;
+	}
+
+	ret = wait_event_interruptible(channel->rx_wait,
+					!list_empty(&channel->rx_msgs_queue));
+	if (ret < 0) {
+		clear_bit(HSC_CH_READ, &channel->flags);
+		hsi_flush(channel->cl);
+		return -EINTR;
+	}
+
+	msg = hsc_get_first_msg(channel, &channel->rx_msgs_queue);
+	if (msg) {
+		if (msg->status != HSI_STATUS_ERROR) {
+			ret = copy_to_user((void __user *)buf,
+			sg_virt(msg->sgt.sgl), hsc_msg_len_get(msg));
+			if (ret)
+				ret = -EFAULT;
+			else
+				ret = hsc_msg_len_get(msg);
+		} else {
+			ret = -EIO;
+		}
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+out:
+	clear_bit(HSC_CH_READ, &channel->flags);
+
+	return ret;
+}
+
+static ssize_t hsc_write(struct file *file, const char __user *buf, size_t len,
+						loff_t *ppos __maybe_unused)
+{
+	struct hsc_channel *channel = file->private_data;
+	struct hsi_msg *msg;
+	ssize_t ret;
+
+	if ((len == 0) || !IS_ALIGNED(len, sizeof(u32)))
+		return -EINVAL;
+	if (len > max_data_size)
+		len = max_data_size;
+	if (channel->ch >= channel->cl->tx_cfg.num_hw_channels)
+		return -ECHRNG;
+	if (test_and_set_bit(HSC_CH_WRITE, &channel->flags))
+		return -EBUSY;
+	msg = hsc_get_first_msg(channel, &channel->free_msgs_list);
+	if (!msg) {
+		clear_bit(HSC_CH_WRITE, &channel->flags);
+		return -ENOSPC;
+	}
+	if (copy_from_user(sg_virt(msg->sgt.sgl), (void __user *)buf, len)) {
+		ret = -EFAULT;
+		goto out;
+	}
+	hsc_msg_len_set(msg, len);
+	msg->complete = hsc_tx_completed;
+	msg->destructor = hsc_tx_msg_destructor;
+	ret = hsi_async_write(channel->cl, msg);
+	if (ret < 0)
+		goto out;
+
+	ret = wait_event_interruptible(channel->tx_wait,
+					!list_empty(&channel->tx_msgs_queue));
+	if (ret < 0) {
+		clear_bit(HSC_CH_WRITE, &channel->flags);
+		hsi_flush(channel->cl);
+		return -EINTR;
+	}
+
+	msg = hsc_get_first_msg(channel, &channel->tx_msgs_queue);
+	if (msg) {
+		if (msg->status == HSI_STATUS_ERROR)
+			ret = -EIO;
+		else
+			ret = hsc_msg_len_get(msg);
+
+		hsc_add_tail(channel, msg, &channel->free_msgs_list);
+	}
+out:
+	clear_bit(HSC_CH_WRITE, &channel->flags);
+
+	return ret;
+}
+
+static long hsc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct hsc_channel *channel = file->private_data;
+	unsigned int state;
+	struct hsc_rx_config rxc;
+	struct hsc_tx_config txc;
+	long ret = 0;
+
+	switch (cmd) {
+	case HSC_RESET:
+		hsi_flush(channel->cl);
+		break;
+	case HSC_SET_PM:
+		if (copy_from_user(&state, (void __user *)arg, sizeof(state)))
+			return -EFAULT;
+		if (state == HSC_PM_DISABLE) {
+			if (test_and_set_bit(HSC_CH_WLINE, &channel->flags))
+				return -EINVAL;
+			ret = hsi_start_tx(channel->cl);
+		} else if (state == HSC_PM_ENABLE) {
+			if (!test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
+				return -EINVAL;
+			ret = hsi_stop_tx(channel->cl);
+		} else {
+			ret = -EINVAL;
+		}
+		break;
+	case HSC_SEND_BREAK:
+		return hsc_break_send(channel->cl);
+	case HSC_SET_RX:
+		if (copy_from_user(&rxc, (void __user *)arg, sizeof(rxc)))
+			return -EFAULT;
+		return hsc_rx_set(channel->cl, &rxc);
+	case HSC_GET_RX:
+		hsc_rx_get(channel->cl, &rxc);
+		if (copy_to_user((void __user *)arg, &rxc, sizeof(rxc)))
+			return -EFAULT;
+		break;
+	case HSC_SET_TX:
+		if (copy_from_user(&txc, (void __user *)arg, sizeof(txc)))
+			return -EFAULT;
+		return hsc_tx_set(channel->cl, &txc);
+	case HSC_GET_TX:
+		hsc_tx_get(channel->cl, &txc);
+		if (copy_to_user((void __user *)arg, &txc, sizeof(txc)))
+			return -EFAULT;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return ret;
+}
+
+static inline void __hsc_port_release(struct hsc_client_data *cl_data)
+{
+	BUG_ON(cl_data->usecnt == 0);
+
+	if (--cl_data->usecnt == 0) {
+		hsi_flush(cl_data->cl);
+		hsi_release_port(cl_data->cl);
+	}
+}
+
+static int hsc_open(struct inode *inode, struct file *file)
+{
+	struct hsc_client_data *cl_data;
+	struct hsc_channel *channel;
+	int ret = 0;
+
+	pr_debug("open, minor = %d\n", iminor(inode));
+
+	cl_data = container_of(inode->i_cdev, struct hsc_client_data, cdev);
+	mutex_lock(&cl_data->lock);
+	channel = cl_data->channels + (iminor(inode) & HSC_CH_MASK);
+
+	if (test_and_set_bit(HSC_CH_OPEN, &channel->flags)) {
+		ret = -EBUSY;
+		goto out;
+	}
+	/*
+	 * Check if we have already claimed the port associated to the HSI
+	 * client. If not then try to claim it, else increase its refcount
+	 */
+	if (cl_data->usecnt == 0) {
+		ret = hsi_claim_port(cl_data->cl, 0);
+		if (ret < 0)
+			goto out;
+		hsi_setup(cl_data->cl);
+	}
+	cl_data->usecnt++;
+
+	ret = hsc_msgs_alloc(channel);
+	if (ret < 0) {
+		__hsc_port_release(cl_data);
+		goto out;
+	}
+
+	file->private_data = channel;
+	mutex_unlock(&cl_data->lock);
+
+	return ret;
+out:
+	mutex_unlock(&cl_data->lock);
+
+	return ret;
+}
+
+static int hsc_release(struct inode *inode __maybe_unused, struct file *file)
+{
+	struct hsc_channel *channel = file->private_data;
+	struct hsc_client_data *cl_data = channel->cl_data;
+
+	mutex_lock(&cl_data->lock);
+	file->private_data = NULL;
+	if (test_and_clear_bit(HSC_CH_WLINE, &channel->flags))
+		hsi_stop_tx(channel->cl);
+	__hsc_port_release(cl_data);
+	hsc_reset_list(channel, &channel->rx_msgs_queue);
+	hsc_reset_list(channel, &channel->tx_msgs_queue);
+	hsc_reset_list(channel, &channel->free_msgs_list);
+	clear_bit(HSC_CH_READ, &channel->flags);
+	clear_bit(HSC_CH_WRITE, &channel->flags);
+	clear_bit(HSC_CH_OPEN, &channel->flags);
+	wake_up(&channel->rx_wait);
+	wake_up(&channel->tx_wait);
+	mutex_unlock(&cl_data->lock);
+
+	return 0;
+}
+
+static const struct file_operations hsc_fops = {
+	.owner		= THIS_MODULE,
+	.read		= hsc_read,
+	.write		= hsc_write,
+	.unlocked_ioctl	= hsc_ioctl,
+	.open		= hsc_open,
+	.release	= hsc_release,
+};
+
+static void hsc_channel_init(struct hsc_channel *channel)
+{
+	init_waitqueue_head(&channel->rx_wait);
+	init_waitqueue_head(&channel->tx_wait);
+	spin_lock_init(&channel->lock);
+	INIT_LIST_HEAD(&channel->free_msgs_list);
+	INIT_LIST_HEAD(&channel->rx_msgs_queue);
+	INIT_LIST_HEAD(&channel->tx_msgs_queue);
+}
+
+static int hsc_probe(struct device *dev)
+{
+	const char devname[] = "hsi_char";
+	struct hsc_client_data *cl_data;
+	struct hsc_channel *channel;
+	struct hsi_client *cl = to_hsi_client(dev);
+	unsigned int hsc_baseminor;
+	dev_t hsc_dev;
+	int ret;
+	int i;
+
+	cl_data = kzalloc(sizeof(*cl_data), GFP_KERNEL);
+	if (!cl_data) {
+		dev_err(dev, "Could not allocate hsc_client_data\n");
+		return -ENOMEM;
+	}
+	hsc_baseminor = HSC_BASEMINOR(hsi_id(cl), hsi_port_id(cl));
+	if (!hsc_major) {
+		ret = alloc_chrdev_region(&hsc_dev, hsc_baseminor,
+						HSC_DEVS, devname);
+		if (ret == 0)
+			hsc_major = MAJOR(hsc_dev);
+	} else {
+		hsc_dev = MKDEV(hsc_major, hsc_baseminor);
+		ret = register_chrdev_region(hsc_dev, HSC_DEVS, devname);
+	}
+	if (ret < 0) {
+		dev_err(dev, "Device %s allocation failed %d\n",
+					hsc_major ? "minor" : "major", ret);
+		goto out1;
+	}
+	mutex_init(&cl_data->lock);
+	hsi_client_set_drvdata(cl, cl_data);
+	cdev_init(&cl_data->cdev, &hsc_fops);
+	cl_data->cdev.owner = THIS_MODULE;
+	cl_data->cl = cl;
+	for (i = 0, channel = cl_data->channels; i < HSC_DEVS; i++, channel++) {
+		hsc_channel_init(channel);
+		channel->ch = i;
+		channel->cl = cl;
+		channel->cl_data = cl_data;
+	}
+
+	/* 1 hsi client -> N char devices (one for each channel) */
+	ret = cdev_add(&cl_data->cdev, hsc_dev, HSC_DEVS);
+	if (ret) {
+		dev_err(dev, "Could not add char device %d\n", ret);
+		goto out2;
+	}
+
+	return 0;
+out2:
+	unregister_chrdev_region(hsc_dev, HSC_DEVS);
+out1:
+	kfree(cl_data);
+
+	return ret;
+}
+
+static int hsc_remove(struct device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct hsc_client_data *cl_data = hsi_client_drvdata(cl);
+	dev_t hsc_dev = cl_data->cdev.dev;
+
+	cdev_del(&cl_data->cdev);
+	unregister_chrdev_region(hsc_dev, HSC_DEVS);
+	hsi_client_set_drvdata(cl, NULL);
+	kfree(cl_data);
+
+	return 0;
+}
+
+static struct hsi_client_driver hsc_driver = {
+	.driver = {
+		.name	= "hsi_char",
+		.owner	= THIS_MODULE,
+		.probe	= hsc_probe,
+		.remove	= hsc_remove,
+	},
+};
+
+static int __init hsc_init(void)
+{
+	int ret;
+
+	if ((max_data_size < 4) || (max_data_size > 0x10000) ||
+		(max_data_size & (max_data_size - 1))) {
+		pr_err("Invalid max read/write data size");
+		return -EINVAL;
+	}
+
+	ret = hsi_register_client_driver(&hsc_driver);
+	if (ret) {
+		pr_err("Error while registering HSI/SSI driver %d", ret);
+		return ret;
+	}
+
+	pr_info("HSI/SSI char device loaded\n");
+
+	return 0;
+}
+module_init(hsc_init);
+
+static void __exit hsc_exit(void)
+{
+	hsi_unregister_client_driver(&hsc_driver);
+	pr_info("HSI char device removed\n");
+}
+module_exit(hsc_exit);
+
+MODULE_AUTHOR("Andras Domokos <andras.domokos@nokia.com>");
+MODULE_ALIAS("hsi:hsi_char");
+MODULE_DESCRIPTION("HSI character device");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hsi/clients/nokia-modem.c b/drivers/hsi/clients/nokia-modem.c
new file mode 100644
index 00000000000..363b780dace
--- /dev/null
+++ b/drivers/hsi/clients/nokia-modem.c
@@ -0,0 +1,285 @@
+/*
+ * nokia-modem.c
+ *
+ * HSI client driver for Nokia N900 modem.
+ *
+ * Copyright (C) 2014 Sebastian Reichel <sre@kernel.org>
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/gpio/consumer.h>
+#include <linux/hsi/hsi.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/hsi/ssi_protocol.h>
+
+static unsigned int pm;
+module_param(pm, int, 0400);
+MODULE_PARM_DESC(pm,
+	"Enable power management (0=disabled, 1=userland based [default])");
+
+struct nokia_modem_gpio {
+	struct gpio_desc	*gpio;
+	const char		*name;
+};
+
+struct nokia_modem_device {
+	struct tasklet_struct	nokia_modem_rst_ind_tasklet;
+	int			nokia_modem_rst_ind_irq;
+	struct device		*device;
+	struct nokia_modem_gpio	*gpios;
+	int			gpio_amount;
+	struct hsi_client	*ssi_protocol;
+};
+
+static void do_nokia_modem_rst_ind_tasklet(unsigned long data)
+{
+	struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
+
+	if (!modem)
+		return;
+
+	dev_info(modem->device, "CMT rst line change detected\n");
+
+	if (modem->ssi_protocol)
+		ssip_reset_event(modem->ssi_protocol);
+}
+
+static irqreturn_t nokia_modem_rst_ind_isr(int irq, void *data)
+{
+	struct nokia_modem_device *modem = (struct nokia_modem_device *)data;
+
+	tasklet_schedule(&modem->nokia_modem_rst_ind_tasklet);
+
+	return IRQ_HANDLED;
+}
+
+static void nokia_modem_gpio_unexport(struct device *dev)
+{
+	struct nokia_modem_device *modem = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < modem->gpio_amount; i++) {
+		sysfs_remove_link(&dev->kobj, modem->gpios[i].name);
+		gpiod_unexport(modem->gpios[i].gpio);
+	}
+}
+
+static int nokia_modem_gpio_probe(struct device *dev)
+{
+	struct device_node *np = dev->of_node;
+	struct nokia_modem_device *modem = dev_get_drvdata(dev);
+	int gpio_count, gpio_name_count, i, err;
+
+	gpio_count = of_gpio_count(np);
+
+	if (gpio_count < 0) {
+		dev_err(dev, "missing gpios: %d\n", gpio_count);
+		return gpio_count;
+	}
+
+	gpio_name_count = of_property_count_strings(np, "gpio-names");
+
+	if (gpio_count != gpio_name_count) {
+		dev_err(dev, "number of gpios does not equal number of gpio names\n");
+		return -EINVAL;
+	}
+
+	modem->gpios = devm_kzalloc(dev, gpio_count *
+				sizeof(struct nokia_modem_gpio), GFP_KERNEL);
+	if (!modem->gpios) {
+		dev_err(dev, "Could not allocate memory for gpios\n");
+		return -ENOMEM;
+	}
+
+	modem->gpio_amount = gpio_count;
+
+	for (i = 0; i < gpio_count; i++) {
+		modem->gpios[i].gpio = devm_gpiod_get_index(dev, NULL, i);
+		if (IS_ERR(modem->gpios[i].gpio)) {
+			dev_err(dev, "Could not get gpio %d\n", i);
+			return PTR_ERR(modem->gpios[i].gpio);
+		}
+
+		err = of_property_read_string_index(np, "gpio-names", i,
+						&(modem->gpios[i].name));
+		if (err) {
+			dev_err(dev, "Could not get gpio name %d\n", i);
+			return err;
+		}
+
+		err = gpiod_direction_output(modem->gpios[i].gpio, 0);
+		if (err)
+			return err;
+
+		err = gpiod_export(modem->gpios[i].gpio, 0);
+		if (err)
+			return err;
+
+		err = gpiod_export_link(dev, modem->gpios[i].name,
+							modem->gpios[i].gpio);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int nokia_modem_probe(struct device *dev)
+{
+	struct device_node *np;
+	struct nokia_modem_device *modem;
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct hsi_port *port = hsi_get_port(cl);
+	int irq, pflags, err;
+	struct hsi_board_info ssip;
+
+	np = dev->of_node;
+	if (!np) {
+		dev_err(dev, "device tree node not found\n");
+		return -ENXIO;
+	}
+
+	modem = devm_kzalloc(dev, sizeof(*modem), GFP_KERNEL);
+	if (!modem) {
+		dev_err(dev, "Could not allocate memory for nokia_modem_device\n");
+		return -ENOMEM;
+	}
+	dev_set_drvdata(dev, modem);
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq < 0) {
+		dev_err(dev, "Invalid rst_ind interrupt (%d)\n", irq);
+		return irq;
+	}
+	modem->nokia_modem_rst_ind_irq = irq;
+	pflags = irq_get_trigger_type(irq);
+
+	tasklet_init(&modem->nokia_modem_rst_ind_tasklet,
+			do_nokia_modem_rst_ind_tasklet, (unsigned long)modem);
+	err = devm_request_irq(dev, irq, nokia_modem_rst_ind_isr,
+				IRQF_DISABLED | pflags, "modem_rst_ind", modem);
+	if (err < 0) {
+		dev_err(dev, "Request rst_ind irq(%d) failed (flags %d)\n",
+								irq, pflags);
+		return err;
+	}
+	enable_irq_wake(irq);
+
+	if(pm) {
+		err = nokia_modem_gpio_probe(dev);
+		if (err < 0) {
+			dev_err(dev, "Could not probe GPIOs\n");
+			goto error1;
+		}
+	}
+
+	ssip.name = "ssi-protocol";
+	ssip.tx_cfg = cl->tx_cfg;
+	ssip.rx_cfg = cl->rx_cfg;
+	ssip.platform_data = NULL;
+	ssip.archdata = NULL;
+
+	modem->ssi_protocol = hsi_new_client(port, &ssip);
+	if (!modem->ssi_protocol) {
+		dev_err(dev, "Could not register ssi-protocol device\n");
+		goto error2;
+	}
+
+	err = device_attach(&modem->ssi_protocol->device);
+	if (err == 0) {
+		dev_err(dev, "Missing ssi-protocol driver\n");
+		err = -EPROBE_DEFER;
+		goto error3;
+	} else if (err < 0) {
+		dev_err(dev, "Could not load ssi-protocol driver (%d)\n", err);
+		goto error3;
+	}
+
+	/* TODO: register cmt-speech hsi client */
+
+	dev_info(dev, "Registered Nokia HSI modem\n");
+
+	return 0;
+
+error3:
+	hsi_remove_client(&modem->ssi_protocol->device, NULL);
+error2:
+	nokia_modem_gpio_unexport(dev);
+error1:
+	disable_irq_wake(modem->nokia_modem_rst_ind_irq);
+	tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
+
+	return err;
+}
+
+static int nokia_modem_remove(struct device *dev)
+{
+	struct nokia_modem_device *modem = dev_get_drvdata(dev);
+
+	if (!modem)
+		return 0;
+
+	if (modem->ssi_protocol) {
+		hsi_remove_client(&modem->ssi_protocol->device, NULL);
+		modem->ssi_protocol = NULL;
+	}
+
+	nokia_modem_gpio_unexport(dev);
+	dev_set_drvdata(dev, NULL);
+	disable_irq_wake(modem->nokia_modem_rst_ind_irq);
+	tasklet_kill(&modem->nokia_modem_rst_ind_tasklet);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id nokia_modem_of_match[] = {
+	{ .compatible = "nokia,n900-modem", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, nokia_modem_of_match);
+#endif
+
+static struct hsi_client_driver nokia_modem_driver = {
+	.driver = {
+		.name	= "nokia-modem",
+		.owner	= THIS_MODULE,
+		.probe	= nokia_modem_probe,
+		.remove	= nokia_modem_remove,
+		.of_match_table = of_match_ptr(nokia_modem_of_match),
+	},
+};
+
+static int __init nokia_modem_init(void)
+{
+	return hsi_register_client_driver(&nokia_modem_driver);
+}
+module_init(nokia_modem_init);
+
+static void __exit nokia_modem_exit(void)
+{
+	hsi_unregister_client_driver(&nokia_modem_driver);
+}
+module_exit(nokia_modem_exit);
+
+MODULE_ALIAS("hsi:nokia-modem");
+MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
+MODULE_DESCRIPTION("HSI driver module for Nokia N900 Modem");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hsi/clients/ssi_protocol.c b/drivers/hsi/clients/ssi_protocol.c
new file mode 100644
index 00000000000..ce4be3738d4
--- /dev/null
+++ b/drivers/hsi/clients/ssi_protocol.c
@@ -0,0 +1,1191 @@
+/*
+ * ssi_protocol.c
+ *
+ * Implementation of the SSI McSAAB improved protocol.
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Copyright (C) 2013 Sebastian Reichel <sre@kernel.org>
+ *
+ * Contact: Carlos Chinea <carlos.chinea@nokia.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include <linux/atomic.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/if_ether.h>
+#include <linux/if_arp.h>
+#include <linux/if_phonet.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/notifier.h>
+#include <linux/scatterlist.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+#include <linux/hsi/hsi.h>
+#include <linux/hsi/ssi_protocol.h>
+
+void ssi_waketest(struct hsi_client *cl, unsigned int enable);
+
+#define SSIP_TXQUEUE_LEN	100
+#define SSIP_MAX_MTU		65535
+#define SSIP_DEFAULT_MTU	4000
+#define PN_MEDIA_SOS		21
+#define SSIP_MIN_PN_HDR		6	/* FIXME: Revisit */
+#define SSIP_WDTOUT		2000	/* FIXME: has to be 500 msecs */
+#define SSIP_KATOUT		15	/* 15 msecs */
+#define SSIP_MAX_CMDS		5 /* Number of pre-allocated commands buffers */
+#define SSIP_BYTES_TO_FRAMES(x) ((((x) - 1) >> 2) + 1)
+#define SSIP_CMT_LOADER_SYNC	0x11223344
+/*
+ * SSI protocol command definitions
+ */
+#define SSIP_COMMAND(data)	((data) >> 28)
+#define SSIP_PAYLOAD(data)	((data) & 0xfffffff)
+/* Commands */
+#define SSIP_SW_BREAK		0
+#define SSIP_BOOTINFO_REQ	1
+#define SSIP_BOOTINFO_RESP	2
+#define SSIP_WAKETEST_RESULT	3
+#define SSIP_START_TRANS	4
+#define SSIP_READY		5
+/* Payloads */
+#define SSIP_DATA_VERSION(data)	((data) & 0xff)
+#define SSIP_LOCAL_VERID	1
+#define SSIP_WAKETEST_OK	0
+#define SSIP_WAKETEST_FAILED	1
+#define SSIP_PDU_LENGTH(data)	(((data) >> 8) & 0xffff)
+#define SSIP_MSG_ID(data)	((data) & 0xff)
+/* Generic Command */
+#define SSIP_CMD(cmd, payload)	(((cmd) << 28) | ((payload) & 0xfffffff))
+/* Commands for the control channel */
+#define SSIP_BOOTINFO_REQ_CMD(ver) \
+		SSIP_CMD(SSIP_BOOTINFO_REQ, SSIP_DATA_VERSION(ver))
+#define SSIP_BOOTINFO_RESP_CMD(ver) \
+		SSIP_CMD(SSIP_BOOTINFO_RESP, SSIP_DATA_VERSION(ver))
+#define SSIP_START_TRANS_CMD(pdulen, id) \
+		SSIP_CMD(SSIP_START_TRANS, (((pdulen) << 8) | SSIP_MSG_ID(id)))
+#define SSIP_READY_CMD		SSIP_CMD(SSIP_READY, 0)
+#define SSIP_SWBREAK_CMD	SSIP_CMD(SSIP_SW_BREAK, 0)
+
+/* Main state machine states */
+enum {
+	INIT,
+	HANDSHAKE,
+	ACTIVE,
+};
+
+/* Send state machine states */
+enum {
+	SEND_IDLE,
+	WAIT4READY,
+	SEND_READY,
+	SENDING,
+	SENDING_SWBREAK,
+};
+
+/* Receive state machine states */
+enum {
+	RECV_IDLE,
+	RECV_READY,
+	RECEIVING,
+};
+
+/**
+ * struct ssi_protocol - SSI protocol (McSAAB) data
+ * @main_state: Main state machine
+ * @send_state: TX state machine
+ * @recv_state: RX state machine
+ * @waketest: Flag to follow wake line test
+ * @rxid: RX data id
+ * @txid: TX data id
+ * @txqueue_len: TX queue length
+ * @tx_wd: TX watchdog
+ * @rx_wd: RX watchdog
+ * @keep_alive: Workaround for SSI HW bug
+ * @lock: To serialize access to this struct
+ * @netdev: Phonet network device
+ * @txqueue: TX data queue
+ * @cmdqueue: Queue of free commands
+ * @cl: HSI client own reference
+ * @link: Link for ssip_list
+ * @tx_usecount: Refcount to keep track the slaves that use the wake line
+ * @channel_id_cmd: HSI channel id for command stream
+ * @channel_id_data: HSI channel id for data stream
+ */
+struct ssi_protocol {
+	unsigned int		main_state;
+	unsigned int		send_state;
+	unsigned int		recv_state;
+	unsigned int		waketest:1;
+	u8			rxid;
+	u8			txid;
+	unsigned int		txqueue_len;
+	struct timer_list	tx_wd;
+	struct timer_list	rx_wd;
+	struct timer_list	keep_alive; /* wake-up workaround */
+	spinlock_t		lock;
+	struct net_device	*netdev;
+	struct list_head	txqueue;
+	struct list_head	cmdqueue;
+	struct hsi_client	*cl;
+	struct list_head	link;
+	atomic_t		tx_usecnt;
+	int			channel_id_cmd;
+	int			channel_id_data;
+};
+
+/* List of ssi protocol instances */
+static LIST_HEAD(ssip_list);
+
+static void ssip_rxcmd_complete(struct hsi_msg *msg);
+
+static inline void ssip_set_cmd(struct hsi_msg *msg, u32 cmd)
+{
+	u32 *data;
+
+	data = sg_virt(msg->sgt.sgl);
+	*data = cmd;
+}
+
+static inline u32 ssip_get_cmd(struct hsi_msg *msg)
+{
+	u32 *data;
+
+	data = sg_virt(msg->sgt.sgl);
+
+	return *data;
+}
+
+static void ssip_skb_to_msg(struct sk_buff *skb, struct hsi_msg *msg)
+{
+	skb_frag_t *frag;
+	struct scatterlist *sg;
+	int i;
+
+	BUG_ON(msg->sgt.nents != (unsigned int)(skb_shinfo(skb)->nr_frags + 1));
+
+	sg = msg->sgt.sgl;
+	sg_set_buf(sg, skb->data, skb_headlen(skb));
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		sg = sg_next(sg);
+		BUG_ON(!sg);
+		frag = &skb_shinfo(skb)->frags[i];
+		sg_set_page(sg, frag->page.p, frag->size, frag->page_offset);
+	}
+}
+
+static void ssip_free_data(struct hsi_msg *msg)
+{
+	struct sk_buff *skb;
+
+	skb = msg->context;
+	pr_debug("free data: msg %p context %p skb %p\n", msg, msg->context,
+								skb);
+	msg->destructor = NULL;
+	dev_kfree_skb(skb);
+	hsi_free_msg(msg);
+}
+
+static struct hsi_msg *ssip_alloc_data(struct ssi_protocol *ssi,
+					struct sk_buff *skb, gfp_t flags)
+{
+	struct hsi_msg *msg;
+
+	msg = hsi_alloc_msg(skb_shinfo(skb)->nr_frags + 1, flags);
+	if (!msg)
+		return NULL;
+	ssip_skb_to_msg(skb, msg);
+	msg->destructor = ssip_free_data;
+	msg->channel = ssi->channel_id_data;
+	msg->context = skb;
+
+	return msg;
+}
+
+static inline void ssip_release_cmd(struct hsi_msg *msg)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(msg->cl);
+
+	dev_dbg(&msg->cl->device, "Release cmd 0x%08x\n", ssip_get_cmd(msg));
+	spin_lock_bh(&ssi->lock);
+	list_add_tail(&msg->link, &ssi->cmdqueue);
+	spin_unlock_bh(&ssi->lock);
+}
+
+static struct hsi_msg *ssip_claim_cmd(struct ssi_protocol *ssi)
+{
+	struct hsi_msg *msg;
+
+	BUG_ON(list_empty(&ssi->cmdqueue));
+
+	spin_lock_bh(&ssi->lock);
+	msg = list_first_entry(&ssi->cmdqueue, struct hsi_msg, link);
+	list_del(&msg->link);
+	spin_unlock_bh(&ssi->lock);
+	msg->destructor = ssip_release_cmd;
+
+	return msg;
+}
+
+static void ssip_free_cmds(struct ssi_protocol *ssi)
+{
+	struct hsi_msg *msg, *tmp;
+
+	list_for_each_entry_safe(msg, tmp, &ssi->cmdqueue, link) {
+		list_del(&msg->link);
+		msg->destructor = NULL;
+		kfree(sg_virt(msg->sgt.sgl));
+		hsi_free_msg(msg);
+	}
+}
+
+static int ssip_alloc_cmds(struct ssi_protocol *ssi)
+{
+	struct hsi_msg *msg;
+	u32 *buf;
+	unsigned int i;
+
+	for (i = 0; i < SSIP_MAX_CMDS; i++) {
+		msg = hsi_alloc_msg(1, GFP_KERNEL);
+		if (!msg)
+			goto out;
+		buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+		if (!buf) {
+			hsi_free_msg(msg);
+			goto out;
+		}
+		sg_init_one(msg->sgt.sgl, buf, sizeof(*buf));
+		msg->channel = ssi->channel_id_cmd;
+		list_add_tail(&msg->link, &ssi->cmdqueue);
+	}
+
+	return 0;
+out:
+	ssip_free_cmds(ssi);
+
+	return -ENOMEM;
+}
+
+static void ssip_set_rxstate(struct ssi_protocol *ssi, unsigned int state)
+{
+	ssi->recv_state = state;
+	switch (state) {
+	case RECV_IDLE:
+		del_timer(&ssi->rx_wd);
+		if (ssi->send_state == SEND_IDLE)
+			del_timer(&ssi->keep_alive);
+		break;
+	case RECV_READY:
+		/* CMT speech workaround */
+		if (atomic_read(&ssi->tx_usecnt))
+			break;
+		/* Otherwise fall through */
+	case RECEIVING:
+		mod_timer(&ssi->keep_alive, jiffies +
+						msecs_to_jiffies(SSIP_KATOUT));
+		mod_timer(&ssi->rx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+		break;
+	default:
+		break;
+	}
+}
+
+static void ssip_set_txstate(struct ssi_protocol *ssi, unsigned int state)
+{
+	ssi->send_state = state;
+	switch (state) {
+	case SEND_IDLE:
+	case SEND_READY:
+		del_timer(&ssi->tx_wd);
+		if (ssi->recv_state == RECV_IDLE)
+			del_timer(&ssi->keep_alive);
+		break;
+	case WAIT4READY:
+	case SENDING:
+	case SENDING_SWBREAK:
+		mod_timer(&ssi->keep_alive,
+				jiffies + msecs_to_jiffies(SSIP_KATOUT));
+		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+		break;
+	default:
+		break;
+	}
+}
+
+struct hsi_client *ssip_slave_get_master(struct hsi_client *slave)
+{
+	struct hsi_client *master = ERR_PTR(-ENODEV);
+	struct ssi_protocol *ssi;
+
+	list_for_each_entry(ssi, &ssip_list, link)
+		if (slave->device.parent == ssi->cl->device.parent) {
+			master = ssi->cl;
+			break;
+		}
+
+	return master;
+}
+EXPORT_SYMBOL_GPL(ssip_slave_get_master);
+
+int ssip_slave_start_tx(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+
+	dev_dbg(&master->device, "start TX %d\n", atomic_read(&ssi->tx_usecnt));
+	spin_lock_bh(&ssi->lock);
+	if (ssi->send_state == SEND_IDLE) {
+		ssip_set_txstate(ssi, WAIT4READY);
+		hsi_start_tx(master);
+	}
+	spin_unlock_bh(&ssi->lock);
+	atomic_inc(&ssi->tx_usecnt);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ssip_slave_start_tx);
+
+int ssip_slave_stop_tx(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+
+	WARN_ON_ONCE(atomic_read(&ssi->tx_usecnt) == 0);
+
+	if (atomic_dec_and_test(&ssi->tx_usecnt)) {
+		spin_lock_bh(&ssi->lock);
+		if ((ssi->send_state == SEND_READY) ||
+			(ssi->send_state == WAIT4READY)) {
+			ssip_set_txstate(ssi, SEND_IDLE);
+			hsi_stop_tx(master);
+		}
+		spin_unlock_bh(&ssi->lock);
+	}
+	dev_dbg(&master->device, "stop TX %d\n", atomic_read(&ssi->tx_usecnt));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ssip_slave_stop_tx);
+
+int ssip_slave_running(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+	return netif_running(ssi->netdev);
+}
+EXPORT_SYMBOL_GPL(ssip_slave_running);
+
+static void ssip_reset(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct list_head *head, *tmp;
+	struct hsi_msg *msg;
+
+	if (netif_running(ssi->netdev))
+		netif_carrier_off(ssi->netdev);
+	hsi_flush(cl);
+	spin_lock_bh(&ssi->lock);
+	if (ssi->send_state != SEND_IDLE)
+		hsi_stop_tx(cl);
+	if (ssi->waketest)
+		ssi_waketest(cl, 0);
+	del_timer(&ssi->rx_wd);
+	del_timer(&ssi->tx_wd);
+	del_timer(&ssi->keep_alive);
+	ssi->main_state = 0;
+	ssi->send_state = 0;
+	ssi->recv_state = 0;
+	ssi->waketest = 0;
+	ssi->rxid = 0;
+	ssi->txid = 0;
+	list_for_each_safe(head, tmp, &ssi->txqueue) {
+		msg = list_entry(head, struct hsi_msg, link);
+		dev_dbg(&cl->device, "Pending TX data\n");
+		list_del(head);
+		ssip_free_data(msg);
+	}
+	ssi->txqueue_len = 0;
+	spin_unlock_bh(&ssi->lock);
+}
+
+static void ssip_dump_state(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	spin_lock_bh(&ssi->lock);
+	dev_err(&cl->device, "Main state: %d\n", ssi->main_state);
+	dev_err(&cl->device, "Recv state: %d\n", ssi->recv_state);
+	dev_err(&cl->device, "Send state: %d\n", ssi->send_state);
+	dev_err(&cl->device, "CMT %s\n", (ssi->main_state == ACTIVE) ?
+							"Online" : "Offline");
+	dev_err(&cl->device, "Wake test %d\n", ssi->waketest);
+	dev_err(&cl->device, "Data RX id: %d\n", ssi->rxid);
+	dev_err(&cl->device, "Data TX id: %d\n", ssi->txid);
+
+	list_for_each_entry(msg, &ssi->txqueue, link)
+		dev_err(&cl->device, "pending TX data (%p)\n", msg);
+	spin_unlock_bh(&ssi->lock);
+}
+
+static void ssip_error(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	ssip_dump_state(cl);
+	ssip_reset(cl);
+	msg = ssip_claim_cmd(ssi);
+	msg->complete = ssip_rxcmd_complete;
+	hsi_async_read(cl, msg);
+}
+
+static void ssip_keep_alive(unsigned long data)
+{
+	struct hsi_client *cl = (struct hsi_client *)data;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	dev_dbg(&cl->device, "Keep alive kick in: m(%d) r(%d) s(%d)\n",
+		ssi->main_state, ssi->recv_state, ssi->send_state);
+
+	spin_lock(&ssi->lock);
+	if (ssi->recv_state == RECV_IDLE)
+		switch (ssi->send_state) {
+		case SEND_READY:
+			if (atomic_read(&ssi->tx_usecnt) == 0)
+				break;
+			/*
+			 * Fall through. Workaround for cmt-speech
+			 * in that case we relay on audio timers.
+			 */
+		case SEND_IDLE:
+			spin_unlock(&ssi->lock);
+			return;
+		}
+	mod_timer(&ssi->keep_alive, jiffies + msecs_to_jiffies(SSIP_KATOUT));
+	spin_unlock(&ssi->lock);
+}
+
+static void ssip_wd(unsigned long data)
+{
+	struct hsi_client *cl = (struct hsi_client *)data;
+
+	dev_err(&cl->device, "Watchdog trigerred\n");
+	ssip_error(cl);
+}
+
+static void ssip_send_bootinfo_req_cmd(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	dev_dbg(&cl->device, "Issuing BOOT INFO REQ command\n");
+	msg = ssip_claim_cmd(ssi);
+	ssip_set_cmd(msg, SSIP_BOOTINFO_REQ_CMD(SSIP_LOCAL_VERID));
+	msg->complete = ssip_release_cmd;
+	hsi_async_write(cl, msg);
+	dev_dbg(&cl->device, "Issuing RX command\n");
+	msg = ssip_claim_cmd(ssi);
+	msg->complete = ssip_rxcmd_complete;
+	hsi_async_read(cl, msg);
+}
+
+static void ssip_start_rx(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	dev_dbg(&cl->device, "RX start M(%d) R(%d)\n", ssi->main_state,
+						ssi->recv_state);
+	spin_lock(&ssi->lock);
+	/*
+	 * We can have two UP events in a row due to a short low
+	 * high transition. Therefore we need to ignore the sencond UP event.
+	 */
+	if ((ssi->main_state != ACTIVE) || (ssi->recv_state == RECV_READY)) {
+		if (ssi->main_state == INIT) {
+			ssi->main_state = HANDSHAKE;
+			spin_unlock(&ssi->lock);
+			ssip_send_bootinfo_req_cmd(cl);
+		} else {
+			spin_unlock(&ssi->lock);
+		}
+		return;
+	}
+	ssip_set_rxstate(ssi, RECV_READY);
+	spin_unlock(&ssi->lock);
+
+	msg = ssip_claim_cmd(ssi);
+	ssip_set_cmd(msg, SSIP_READY_CMD);
+	msg->complete = ssip_release_cmd;
+	dev_dbg(&cl->device, "Send READY\n");
+	hsi_async_write(cl, msg);
+}
+
+static void ssip_stop_rx(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	dev_dbg(&cl->device, "RX stop M(%d)\n", ssi->main_state);
+	spin_lock(&ssi->lock);
+	if (likely(ssi->main_state == ACTIVE))
+		ssip_set_rxstate(ssi, RECV_IDLE);
+	spin_unlock(&ssi->lock);
+}
+
+static void ssip_free_strans(struct hsi_msg *msg)
+{
+	ssip_free_data(msg->context);
+	ssip_release_cmd(msg);
+}
+
+static void ssip_strans_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *data;
+
+	data = msg->context;
+	ssip_release_cmd(msg);
+	spin_lock(&ssi->lock);
+	ssip_set_txstate(ssi, SENDING);
+	spin_unlock(&ssi->lock);
+	hsi_async_write(cl, data);
+}
+
+static int ssip_xmit(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg, *dmsg;
+	struct sk_buff *skb;
+
+	spin_lock_bh(&ssi->lock);
+	if (list_empty(&ssi->txqueue)) {
+		spin_unlock_bh(&ssi->lock);
+		return 0;
+	}
+	dmsg = list_first_entry(&ssi->txqueue, struct hsi_msg, link);
+	list_del(&dmsg->link);
+	ssi->txqueue_len--;
+	spin_unlock_bh(&ssi->lock);
+
+	msg = ssip_claim_cmd(ssi);
+	skb = dmsg->context;
+	msg->context = dmsg;
+	msg->complete = ssip_strans_complete;
+	msg->destructor = ssip_free_strans;
+
+	spin_lock_bh(&ssi->lock);
+	ssip_set_cmd(msg, SSIP_START_TRANS_CMD(SSIP_BYTES_TO_FRAMES(skb->len),
+								ssi->txid));
+	ssi->txid++;
+	ssip_set_txstate(ssi, SENDING);
+	spin_unlock_bh(&ssi->lock);
+
+	dev_dbg(&cl->device, "Send STRANS (%d frames)\n",
+						SSIP_BYTES_TO_FRAMES(skb->len));
+
+	return hsi_async_write(cl, msg);
+}
+
+/* In soft IRQ context */
+static void ssip_pn_rx(struct sk_buff *skb)
+{
+	struct net_device *dev = skb->dev;
+
+	if (unlikely(!netif_running(dev))) {
+		dev_dbg(&dev->dev, "Drop RX packet\n");
+		dev->stats.rx_dropped++;
+		dev_kfree_skb(skb);
+		return;
+	}
+	if (unlikely(!pskb_may_pull(skb, SSIP_MIN_PN_HDR))) {
+		dev_dbg(&dev->dev, "Error drop RX packet\n");
+		dev->stats.rx_errors++;
+		dev->stats.rx_length_errors++;
+		dev_kfree_skb(skb);
+		return;
+	}
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += skb->len;
+
+	/* length field is exchanged in network byte order */
+	((u16 *)skb->data)[2] = ntohs(((u16 *)skb->data)[2]);
+	dev_dbg(&dev->dev, "RX length fixed (%04x -> %u)\n",
+			((u16 *)skb->data)[2], ntohs(((u16 *)skb->data)[2]));
+
+	skb->protocol = htons(ETH_P_PHONET);
+	skb_reset_mac_header(skb);
+	__skb_pull(skb, 1);
+	netif_rx(skb);
+}
+
+static void ssip_rx_data_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct sk_buff *skb;
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&cl->device, "RX data error\n");
+		ssip_free_data(msg);
+		ssip_error(cl);
+		return;
+	}
+	del_timer(&ssi->rx_wd); /* FIXME: Revisit */
+	skb = msg->context;
+	ssip_pn_rx(skb);
+	hsi_free_msg(msg);
+}
+
+static void ssip_rx_bootinforeq(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	/* Workaroud: Ignore CMT Loader message leftover */
+	if (cmd == SSIP_CMT_LOADER_SYNC)
+		return;
+
+	switch (ssi->main_state) {
+	case ACTIVE:
+		dev_err(&cl->device, "Boot info req on active state\n");
+		ssip_error(cl);
+		/* Fall through */
+	case INIT:
+		spin_lock(&ssi->lock);
+		ssi->main_state = HANDSHAKE;
+		if (!ssi->waketest) {
+			ssi->waketest = 1;
+			ssi_waketest(cl, 1); /* FIXME: To be removed */
+		}
+		/* Start boot handshake watchdog */
+		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+		spin_unlock(&ssi->lock);
+		dev_dbg(&cl->device, "Send BOOTINFO_RESP\n");
+		if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
+			dev_warn(&cl->device, "boot info req verid mismatch\n");
+		msg = ssip_claim_cmd(ssi);
+		ssip_set_cmd(msg, SSIP_BOOTINFO_RESP_CMD(SSIP_LOCAL_VERID));
+		msg->complete = ssip_release_cmd;
+		hsi_async_write(cl, msg);
+		break;
+	case HANDSHAKE:
+		/* Ignore */
+		break;
+	default:
+		dev_dbg(&cl->device, "Wrong state M(%d)\n", ssi->main_state);
+		break;
+	}
+}
+
+static void ssip_rx_bootinforesp(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	if (SSIP_DATA_VERSION(cmd) != SSIP_LOCAL_VERID)
+		dev_warn(&cl->device, "boot info resp verid mismatch\n");
+
+	spin_lock(&ssi->lock);
+	if (ssi->main_state != ACTIVE)
+		/* Use tx_wd as a boot watchdog in non ACTIVE state */
+		mod_timer(&ssi->tx_wd, jiffies + msecs_to_jiffies(SSIP_WDTOUT));
+	else
+		dev_dbg(&cl->device, "boot info resp ignored M(%d)\n",
+							ssi->main_state);
+	spin_unlock(&ssi->lock);
+}
+
+static void ssip_rx_waketest(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	unsigned int wkres = SSIP_PAYLOAD(cmd);
+
+	spin_lock(&ssi->lock);
+	if (ssi->main_state != HANDSHAKE) {
+		dev_dbg(&cl->device, "wake lines test ignored M(%d)\n",
+							ssi->main_state);
+		spin_unlock(&ssi->lock);
+		return;
+	}
+	if (ssi->waketest) {
+		ssi->waketest = 0;
+		ssi_waketest(cl, 0); /* FIXME: To be removed */
+	}
+	ssi->main_state = ACTIVE;
+	del_timer(&ssi->tx_wd); /* Stop boot handshake timer */
+	spin_unlock(&ssi->lock);
+
+	dev_notice(&cl->device, "WAKELINES TEST %s\n",
+				wkres & SSIP_WAKETEST_FAILED ? "FAILED" : "OK");
+	if (wkres & SSIP_WAKETEST_FAILED) {
+		ssip_error(cl);
+		return;
+	}
+	dev_dbg(&cl->device, "CMT is ONLINE\n");
+	netif_wake_queue(ssi->netdev);
+	netif_carrier_on(ssi->netdev);
+}
+
+static void ssip_rx_ready(struct hsi_client *cl)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	spin_lock(&ssi->lock);
+	if (unlikely(ssi->main_state != ACTIVE)) {
+		dev_dbg(&cl->device, "READY on wrong state: S(%d) M(%d)\n",
+					ssi->send_state, ssi->main_state);
+		spin_unlock(&ssi->lock);
+		return;
+	}
+	if (ssi->send_state != WAIT4READY) {
+		dev_dbg(&cl->device, "Ignore spurious READY command\n");
+		spin_unlock(&ssi->lock);
+		return;
+	}
+	ssip_set_txstate(ssi, SEND_READY);
+	spin_unlock(&ssi->lock);
+	ssip_xmit(cl);
+}
+
+static void ssip_rx_strans(struct hsi_client *cl, u32 cmd)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct sk_buff *skb;
+	struct hsi_msg *msg;
+	int len = SSIP_PDU_LENGTH(cmd);
+
+	dev_dbg(&cl->device, "RX strans: %d frames\n", len);
+	spin_lock(&ssi->lock);
+	if (unlikely(ssi->main_state != ACTIVE)) {
+		dev_err(&cl->device, "START TRANS wrong state: S(%d) M(%d)\n",
+					ssi->send_state, ssi->main_state);
+		spin_unlock(&ssi->lock);
+		return;
+	}
+	ssip_set_rxstate(ssi, RECEIVING);
+	if (unlikely(SSIP_MSG_ID(cmd) != ssi->rxid)) {
+		dev_err(&cl->device, "START TRANS id %d expeceted %d\n",
+					SSIP_MSG_ID(cmd), ssi->rxid);
+		spin_unlock(&ssi->lock);
+		goto out1;
+	}
+	ssi->rxid++;
+	spin_unlock(&ssi->lock);
+	skb = netdev_alloc_skb(ssi->netdev, len * 4);
+	if (unlikely(!skb)) {
+		dev_err(&cl->device, "No memory for rx skb\n");
+		goto out1;
+	}
+	skb->dev = ssi->netdev;
+	skb_put(skb, len * 4);
+	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
+	if (unlikely(!msg)) {
+		dev_err(&cl->device, "No memory for RX data msg\n");
+		goto out2;
+	}
+	msg->complete = ssip_rx_data_complete;
+	hsi_async_read(cl, msg);
+
+	return;
+out2:
+	dev_kfree_skb(skb);
+out1:
+	ssip_error(cl);
+}
+
+static void ssip_rxcmd_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	u32 cmd = ssip_get_cmd(msg);
+	unsigned int cmdid = SSIP_COMMAND(cmd);
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&cl->device, "RX error detected\n");
+		ssip_release_cmd(msg);
+		ssip_error(cl);
+		return;
+	}
+	hsi_async_read(cl, msg);
+	dev_dbg(&cl->device, "RX cmd: 0x%08x\n", cmd);
+	switch (cmdid) {
+	case SSIP_SW_BREAK:
+		/* Ignored */
+		break;
+	case SSIP_BOOTINFO_REQ:
+		ssip_rx_bootinforeq(cl, cmd);
+		break;
+	case SSIP_BOOTINFO_RESP:
+		ssip_rx_bootinforesp(cl, cmd);
+		break;
+	case SSIP_WAKETEST_RESULT:
+		ssip_rx_waketest(cl, cmd);
+		break;
+	case SSIP_START_TRANS:
+		ssip_rx_strans(cl, cmd);
+		break;
+	case SSIP_READY:
+		ssip_rx_ready(cl);
+		break;
+	default:
+		dev_warn(&cl->device, "command 0x%08x not supported\n", cmd);
+		break;
+	}
+}
+
+static void ssip_swbreak_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	ssip_release_cmd(msg);
+	spin_lock(&ssi->lock);
+	if (list_empty(&ssi->txqueue)) {
+		if (atomic_read(&ssi->tx_usecnt)) {
+			ssip_set_txstate(ssi, SEND_READY);
+		} else {
+			ssip_set_txstate(ssi, SEND_IDLE);
+			hsi_stop_tx(cl);
+		}
+		spin_unlock(&ssi->lock);
+	} else {
+		spin_unlock(&ssi->lock);
+		ssip_xmit(cl);
+	}
+	netif_wake_queue(ssi->netdev);
+}
+
+static void ssip_tx_data_complete(struct hsi_msg *msg)
+{
+	struct hsi_client *cl = msg->cl;
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *cmsg;
+
+	if (msg->status == HSI_STATUS_ERROR) {
+		dev_err(&cl->device, "TX data error\n");
+		ssip_error(cl);
+		goto out;
+	}
+	spin_lock(&ssi->lock);
+	if (list_empty(&ssi->txqueue)) {
+		ssip_set_txstate(ssi, SENDING_SWBREAK);
+		spin_unlock(&ssi->lock);
+		cmsg = ssip_claim_cmd(ssi);
+		ssip_set_cmd(cmsg, SSIP_SWBREAK_CMD);
+		cmsg->complete = ssip_swbreak_complete;
+		dev_dbg(&cl->device, "Send SWBREAK\n");
+		hsi_async_write(cl, cmsg);
+	} else {
+		spin_unlock(&ssi->lock);
+		ssip_xmit(cl);
+	}
+out:
+	ssip_free_data(msg);
+}
+
+void ssip_port_event(struct hsi_client *cl, unsigned long event)
+{
+	switch (event) {
+	case HSI_EVENT_START_RX:
+		ssip_start_rx(cl);
+		break;
+	case HSI_EVENT_STOP_RX:
+		ssip_stop_rx(cl);
+		break;
+	default:
+		return;
+	}
+}
+
+static int ssip_pn_open(struct net_device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	int err;
+
+	err = hsi_claim_port(cl, 1);
+	if (err < 0) {
+		dev_err(&cl->device, "SSI port already claimed\n");
+		return err;
+	}
+	err = hsi_register_port_event(cl, ssip_port_event);
+	if (err < 0) {
+		dev_err(&cl->device, "Register HSI port event failed (%d)\n",
+			err);
+		return err;
+	}
+	dev_dbg(&cl->device, "Configuring SSI port\n");
+	hsi_setup(cl);
+	spin_lock_bh(&ssi->lock);
+	if (!ssi->waketest) {
+		ssi->waketest = 1;
+		ssi_waketest(cl, 1); /* FIXME: To be removed */
+	}
+	ssi->main_state = INIT;
+	spin_unlock_bh(&ssi->lock);
+
+	return 0;
+}
+
+static int ssip_pn_stop(struct net_device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
+
+	ssip_reset(cl);
+	hsi_unregister_port_event(cl);
+	hsi_release_port(cl);
+
+	return 0;
+}
+
+static int ssip_pn_set_mtu(struct net_device *dev, int new_mtu)
+{
+	if (new_mtu > SSIP_MAX_MTU || new_mtu < PHONET_MIN_MTU)
+		return -EINVAL;
+	dev->mtu = new_mtu;
+
+	return 0;
+}
+
+static int ssip_pn_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev->dev.parent);
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+	struct hsi_msg *msg;
+
+	if ((skb->protocol != htons(ETH_P_PHONET)) ||
+					(skb->len < SSIP_MIN_PN_HDR))
+		goto drop;
+	/* Pad to 32-bits - FIXME: Revisit*/
+	if ((skb->len & 3) && skb_pad(skb, 4 - (skb->len & 3)))
+		goto drop;
+
+	/*
+	 * Modem sends Phonet messages over SSI with its own endianess...
+	 * Assume that modem has the same endianess as we do.
+	 */
+	if (skb_cow_head(skb, 0))
+		goto drop;
+
+	/* length field is exchanged in network byte order */
+	((u16 *)skb->data)[2] = htons(((u16 *)skb->data)[2]);
+
+	msg = ssip_alloc_data(ssi, skb, GFP_ATOMIC);
+	if (!msg) {
+		dev_dbg(&cl->device, "Dropping tx data: No memory\n");
+		goto drop;
+	}
+	msg->complete = ssip_tx_data_complete;
+
+	spin_lock_bh(&ssi->lock);
+	if (unlikely(ssi->main_state != ACTIVE)) {
+		spin_unlock_bh(&ssi->lock);
+		dev_dbg(&cl->device, "Dropping tx data: CMT is OFFLINE\n");
+		goto drop2;
+	}
+	list_add_tail(&msg->link, &ssi->txqueue);
+	ssi->txqueue_len++;
+	if (dev->tx_queue_len < ssi->txqueue_len) {
+		dev_info(&cl->device, "TX queue full %d\n", ssi->txqueue_len);
+		netif_stop_queue(dev);
+	}
+	if (ssi->send_state == SEND_IDLE) {
+		ssip_set_txstate(ssi, WAIT4READY);
+		spin_unlock_bh(&ssi->lock);
+		dev_dbg(&cl->device, "Start TX qlen %d\n", ssi->txqueue_len);
+		hsi_start_tx(cl);
+	} else if (ssi->send_state == SEND_READY) {
+		/* Needed for cmt-speech workaround */
+		dev_dbg(&cl->device, "Start TX on SEND READY qlen %d\n",
+							ssi->txqueue_len);
+		spin_unlock_bh(&ssi->lock);
+		ssip_xmit(cl);
+	} else {
+		spin_unlock_bh(&ssi->lock);
+	}
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb->len;
+
+	return 0;
+drop2:
+	hsi_free_msg(msg);
+drop:
+	dev->stats.tx_dropped++;
+	dev_kfree_skb(skb);
+
+	return 0;
+}
+
+/* CMT reset event handler */
+void ssip_reset_event(struct hsi_client *master)
+{
+	struct ssi_protocol *ssi = hsi_client_drvdata(master);
+	dev_err(&ssi->cl->device, "CMT reset detected!\n");
+	ssip_error(ssi->cl);
+}
+EXPORT_SYMBOL_GPL(ssip_reset_event);
+
+static const struct net_device_ops ssip_pn_ops = {
+	.ndo_open	= ssip_pn_open,
+	.ndo_stop	= ssip_pn_stop,
+	.ndo_start_xmit	= ssip_pn_xmit,
+	.ndo_change_mtu	= ssip_pn_set_mtu,
+};
+
+static void ssip_pn_setup(struct net_device *dev)
+{
+	dev->features		= 0;
+	dev->netdev_ops		= &ssip_pn_ops;
+	dev->type		= ARPHRD_PHONET;
+	dev->flags		= IFF_POINTOPOINT | IFF_NOARP;
+	dev->mtu		= SSIP_DEFAULT_MTU;
+	dev->hard_header_len	= 1;
+	dev->dev_addr[0]	= PN_MEDIA_SOS;
+	dev->addr_len		= 1;
+	dev->tx_queue_len	= SSIP_TXQUEUE_LEN;
+
+	dev->destructor		= free_netdev;
+	dev->header_ops		= &phonet_header_ops;
+}
+
+static int ssi_protocol_probe(struct device *dev)
+{
+	static const char ifname[] = "phonet%d";
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct ssi_protocol *ssi;
+	int err;
+
+	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
+	if (!ssi) {
+		dev_err(dev, "No memory for ssi protocol\n");
+		return -ENOMEM;
+	}
+
+	spin_lock_init(&ssi->lock);
+	init_timer_deferrable(&ssi->rx_wd);
+	init_timer_deferrable(&ssi->tx_wd);
+	init_timer(&ssi->keep_alive);
+	ssi->rx_wd.data = (unsigned long)cl;
+	ssi->rx_wd.function = ssip_wd;
+	ssi->tx_wd.data = (unsigned long)cl;
+	ssi->tx_wd.function = ssip_wd;
+	ssi->keep_alive.data = (unsigned long)cl;
+	ssi->keep_alive.function = ssip_keep_alive;
+	INIT_LIST_HEAD(&ssi->txqueue);
+	INIT_LIST_HEAD(&ssi->cmdqueue);
+	atomic_set(&ssi->tx_usecnt, 0);
+	hsi_client_set_drvdata(cl, ssi);
+	ssi->cl = cl;
+
+	ssi->channel_id_cmd = hsi_get_channel_id_by_name(cl, "mcsaab-control");
+	if (ssi->channel_id_cmd < 0) {
+		err = ssi->channel_id_cmd;
+		dev_err(dev, "Could not get cmd channel (%d)\n", err);
+		goto out;
+	}
+
+	ssi->channel_id_data = hsi_get_channel_id_by_name(cl, "mcsaab-data");
+	if (ssi->channel_id_data < 0) {
+		err = ssi->channel_id_data;
+		dev_err(dev, "Could not get data channel (%d)\n", err);
+		goto out;
+	}
+
+	err = ssip_alloc_cmds(ssi);
+	if (err < 0) {
+		dev_err(dev, "No memory for commands\n");
+		goto out;
+	}
+
+	ssi->netdev = alloc_netdev(0, ifname, ssip_pn_setup);
+	if (!ssi->netdev) {
+		dev_err(dev, "No memory for netdev\n");
+		err = -ENOMEM;
+		goto out1;
+	}
+
+	SET_NETDEV_DEV(ssi->netdev, dev);
+	netif_carrier_off(ssi->netdev);
+	err = register_netdev(ssi->netdev);
+	if (err < 0) {
+		dev_err(dev, "Register netdev failed (%d)\n", err);
+		goto out2;
+	}
+
+	list_add(&ssi->link, &ssip_list);
+
+	dev_dbg(dev, "channel configuration: cmd=%d, data=%d\n",
+		ssi->channel_id_cmd, ssi->channel_id_data);
+
+	return 0;
+out2:
+	free_netdev(ssi->netdev);
+out1:
+	ssip_free_cmds(ssi);
+out:
+	kfree(ssi);
+
+	return err;
+}
+
+static int ssi_protocol_remove(struct device *dev)
+{
+	struct hsi_client *cl = to_hsi_client(dev);
+	struct ssi_protocol *ssi = hsi_client_drvdata(cl);
+
+	list_del(&ssi->link);
+	unregister_netdev(ssi->netdev);
+	ssip_free_cmds(ssi);
+	hsi_client_set_drvdata(cl, NULL);
+	kfree(ssi);
+
+	return 0;
+}
+
+static struct hsi_client_driver ssip_driver = {
+	.driver = {
+		.name	= "ssi-protocol",
+		.owner	= THIS_MODULE,
+		.probe	= ssi_protocol_probe,
+		.remove	= ssi_protocol_remove,
+	},
+};
+
+static int __init ssip_init(void)
+{
+	pr_info("SSI protocol aka McSAAB added\n");
+
+	return hsi_register_client_driver(&ssip_driver);
+}
+module_init(ssip_init);
+
+static void __exit ssip_exit(void)
+{
+	hsi_unregister_client_driver(&ssip_driver);
+	pr_info("SSI protocol driver removed\n");
+}
+module_exit(ssip_exit);
+
+MODULE_ALIAS("hsi:ssi-protocol");
+MODULE_AUTHOR("Carlos Chinea <carlos.chinea@nokia.com>");
+MODULE_AUTHOR("Remi Denis-Courmont <remi.denis-courmont@nokia.com>");
+MODULE_DESCRIPTION("SSI protocol improved aka McSAAB");
+MODULE_LICENSE("GPL");