From: Christian Gromm <christian.gromm@microchip.com>
Date: Tue, 21 Nov 2017 14:04:36 +0000 (+0100)
Subject: staging: most: cdev: rename module
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7b9cdcf6ea8062b4a003b0a06601d94a52f95eeb;p=linux.git

staging: most: cdev: rename module

This patch renames the folder of the cdev module. This is needed
to clear the directory layout.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/most/Kconfig b/drivers/staging/most/Kconfig
index 2045f7ac50817..60a2825e60762 100644
--- a/drivers/staging/most/Kconfig
+++ b/drivers/staging/most/Kconfig
@@ -17,7 +17,7 @@ menuconfig MOST
 
 if MOST
 
-source "drivers/staging/most/aim-cdev/Kconfig"
+source "drivers/staging/most/cdev/Kconfig"
 
 source "drivers/staging/most/aim-network/Kconfig"
 
diff --git a/drivers/staging/most/aim-cdev/Kconfig b/drivers/staging/most/aim-cdev/Kconfig
deleted file mode 100644
index 3c59f1bac1276..0000000000000
--- a/drivers/staging/most/aim-cdev/Kconfig
+++ /dev/null
@@ -1,12 +0,0 @@
-#
-# MOST Cdev configuration
-#
-
-config AIM_CDEV
-	tristate "Cdev AIM"
-
-	---help---
-	  Say Y here if you want to commumicate via character devices.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called aim_cdev.
\ No newline at end of file
diff --git a/drivers/staging/most/aim-cdev/cdev.c b/drivers/staging/most/aim-cdev/cdev.c
deleted file mode 100644
index 3ae9246c0c5c2..0000000000000
--- a/drivers/staging/most/aim-cdev/cdev.c
+++ /dev/null
@@ -1,558 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * cdev.c - Application interfacing module for character devices
- *
- * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/fs.h>
-#include <linux/slab.h>
-#include <linux/device.h>
-#include <linux/cdev.h>
-#include <linux/poll.h>
-#include <linux/kfifo.h>
-#include <linux/uaccess.h>
-#include <linux/idr.h>
-#include "most/core.h"
-
-static dev_t aim_devno;
-static struct class *aim_class;
-static struct ida minor_id;
-static unsigned int major;
-static struct most_aim cdev_aim;
-
-struct aim_channel {
-	wait_queue_head_t wq;
-	spinlock_t unlink;	/* synchronization lock to unlink channels */
-	struct cdev cdev;
-	struct device *dev;
-	struct mutex io_mutex;
-	struct most_interface *iface;
-	struct most_channel_config *cfg;
-	unsigned int channel_id;
-	dev_t devno;
-	size_t mbo_offs;
-	DECLARE_KFIFO_PTR(fifo, typeof(struct mbo *));
-	int access_ref;
-	struct list_head list;
-};
-
-#define to_channel(d) container_of(d, struct aim_channel, cdev)
-static struct list_head channel_list;
-static spinlock_t ch_list_lock;
-
-static inline bool ch_has_mbo(struct aim_channel *c)
-{
-	return channel_has_mbo(c->iface, c->channel_id, &cdev_aim) > 0;
-}
-
-static inline bool ch_get_mbo(struct aim_channel *c, struct mbo **mbo)
-{
-	if (!kfifo_peek(&c->fifo, mbo)) {
-		*mbo = most_get_mbo(c->iface, c->channel_id, &cdev_aim);
-		if (*mbo)
-			kfifo_in(&c->fifo, mbo, 1);
-	}
-	return *mbo;
-}
-
-static struct aim_channel *get_channel(struct most_interface *iface, int id)
-{
-	struct aim_channel *c, *tmp;
-	unsigned long flags;
-	int found_channel = 0;
-
-	spin_lock_irqsave(&ch_list_lock, flags);
-	list_for_each_entry_safe(c, tmp, &channel_list, list) {
-		if ((c->iface == iface) && (c->channel_id == id)) {
-			found_channel = 1;
-			break;
-		}
-	}
-	spin_unlock_irqrestore(&ch_list_lock, flags);
-	if (!found_channel)
-		return NULL;
-	return c;
-}
-
-static void stop_channel(struct aim_channel *c)
-{
-	struct mbo *mbo;
-
-	while (kfifo_out((struct kfifo *)&c->fifo, &mbo, 1))
-		most_put_mbo(mbo);
-	most_stop_channel(c->iface, c->channel_id, &cdev_aim);
-}
-
-static void destroy_cdev(struct aim_channel *c)
-{
-	unsigned long flags;
-
-	device_destroy(aim_class, c->devno);
-	cdev_del(&c->cdev);
-	spin_lock_irqsave(&ch_list_lock, flags);
-	list_del(&c->list);
-	spin_unlock_irqrestore(&ch_list_lock, flags);
-}
-
-static void destroy_channel(struct aim_channel *c)
-{
-	ida_simple_remove(&minor_id, MINOR(c->devno));
-	kfifo_free(&c->fifo);
-	kfree(c);
-}
-
-/**
- * aim_open - implements the syscall to open the device
- * @inode: inode pointer
- * @filp: file pointer
- *
- * This stores the channel pointer in the private data field of
- * the file structure and activates the channel within the core.
- */
-static int aim_open(struct inode *inode, struct file *filp)
-{
-	struct aim_channel *c;
-	int ret;
-
-	c = to_channel(inode->i_cdev);
-	filp->private_data = c;
-
-	if (((c->cfg->direction == MOST_CH_RX) &&
-	     ((filp->f_flags & O_ACCMODE) != O_RDONLY)) ||
-	     ((c->cfg->direction == MOST_CH_TX) &&
-		((filp->f_flags & O_ACCMODE) != O_WRONLY))) {
-		pr_info("WARN: Access flags mismatch\n");
-		return -EACCES;
-	}
-
-	mutex_lock(&c->io_mutex);
-	if (!c->dev) {
-		pr_info("WARN: Device is destroyed\n");
-		mutex_unlock(&c->io_mutex);
-		return -ENODEV;
-	}
-
-	if (c->access_ref) {
-		pr_info("WARN: Device is busy\n");
-		mutex_unlock(&c->io_mutex);
-		return -EBUSY;
-	}
-
-	c->mbo_offs = 0;
-	ret = most_start_channel(c->iface, c->channel_id, &cdev_aim);
-	if (!ret)
-		c->access_ref = 1;
-	mutex_unlock(&c->io_mutex);
-	return ret;
-}
-
-/**
- * aim_close - implements the syscall to close the device
- * @inode: inode pointer
- * @filp: file pointer
- *
- * This stops the channel within the core.
- */
-static int aim_close(struct inode *inode, struct file *filp)
-{
-	struct aim_channel *c = to_channel(inode->i_cdev);
-
-	mutex_lock(&c->io_mutex);
-	spin_lock(&c->unlink);
-	c->access_ref = 0;
-	spin_unlock(&c->unlink);
-	if (c->dev) {
-		stop_channel(c);
-		mutex_unlock(&c->io_mutex);
-	} else {
-		mutex_unlock(&c->io_mutex);
-		destroy_channel(c);
-	}
-	return 0;
-}
-
-/**
- * aim_write - implements the syscall to write to the device
- * @filp: file pointer
- * @buf: pointer to user buffer
- * @count: number of bytes to write
- * @offset: offset from where to start writing
- */
-static ssize_t aim_write(struct file *filp, const char __user *buf,
-			 size_t count, loff_t *offset)
-{
-	int ret;
-	size_t to_copy, left;
-	struct mbo *mbo = NULL;
-	struct aim_channel *c = filp->private_data;
-
-	mutex_lock(&c->io_mutex);
-	while (c->dev && !ch_get_mbo(c, &mbo)) {
-		mutex_unlock(&c->io_mutex);
-
-		if ((filp->f_flags & O_NONBLOCK))
-			return -EAGAIN;
-		if (wait_event_interruptible(c->wq, ch_has_mbo(c) || !c->dev))
-			return -ERESTARTSYS;
-		mutex_lock(&c->io_mutex);
-	}
-
-	if (unlikely(!c->dev)) {
-		ret = -ENODEV;
-		goto unlock;
-	}
-
-	to_copy = min(count, c->cfg->buffer_size - c->mbo_offs);
-	left = copy_from_user(mbo->virt_address + c->mbo_offs, buf, to_copy);
-	if (left == to_copy) {
-		ret = -EFAULT;
-		goto unlock;
-	}
-
-	c->mbo_offs += to_copy - left;
-	if (c->mbo_offs >= c->cfg->buffer_size ||
-	    c->cfg->data_type == MOST_CH_CONTROL ||
-	    c->cfg->data_type == MOST_CH_ASYNC) {
-		kfifo_skip(&c->fifo);
-		mbo->buffer_length = c->mbo_offs;
-		c->mbo_offs = 0;
-		most_submit_mbo(mbo);
-	}
-
-	ret = to_copy - left;
-unlock:
-	mutex_unlock(&c->io_mutex);
-	return ret;
-}
-
-/**
- * aim_read - implements the syscall to read from the device
- * @filp: file pointer
- * @buf: pointer to user buffer
- * @count: number of bytes to read
- * @offset: offset from where to start reading
- */
-static ssize_t
-aim_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
-{
-	size_t to_copy, not_copied, copied;
-	struct mbo *mbo;
-	struct aim_channel *c = filp->private_data;
-
-	mutex_lock(&c->io_mutex);
-	while (c->dev && !kfifo_peek(&c->fifo, &mbo)) {
-		mutex_unlock(&c->io_mutex);
-		if (filp->f_flags & O_NONBLOCK)
-			return -EAGAIN;
-		if (wait_event_interruptible(c->wq,
-					     (!kfifo_is_empty(&c->fifo) ||
-					      (!c->dev))))
-			return -ERESTARTSYS;
-		mutex_lock(&c->io_mutex);
-	}
-
-	/* make sure we don't submit to gone devices */
-	if (unlikely(!c->dev)) {
-		mutex_unlock(&c->io_mutex);
-		return -ENODEV;
-	}
-
-	to_copy = min_t(size_t,
-			count,
-			mbo->processed_length - c->mbo_offs);
-
-	not_copied = copy_to_user(buf,
-				  mbo->virt_address + c->mbo_offs,
-				  to_copy);
-
-	copied = to_copy - not_copied;
-
-	c->mbo_offs += copied;
-	if (c->mbo_offs >= mbo->processed_length) {
-		kfifo_skip(&c->fifo);
-		most_put_mbo(mbo);
-		c->mbo_offs = 0;
-	}
-	mutex_unlock(&c->io_mutex);
-	return copied;
-}
-
-static unsigned int aim_poll(struct file *filp, poll_table *wait)
-{
-	struct aim_channel *c = filp->private_data;
-	unsigned int mask = 0;
-
-	poll_wait(filp, &c->wq, wait);
-
-	if (c->cfg->direction == MOST_CH_RX) {
-		if (!kfifo_is_empty(&c->fifo))
-			mask |= POLLIN | POLLRDNORM;
-	} else {
-		if (!kfifo_is_empty(&c->fifo) || ch_has_mbo(c))
-			mask |= POLLOUT | POLLWRNORM;
-	}
-	return mask;
-}
-
-/**
- * Initialization of struct file_operations
- */
-static const struct file_operations channel_fops = {
-	.owner = THIS_MODULE,
-	.read = aim_read,
-	.write = aim_write,
-	.open = aim_open,
-	.release = aim_close,
-	.poll = aim_poll,
-};
-
-/**
- * aim_disconnect_channel - disconnect a channel
- * @iface: pointer to interface instance
- * @channel_id: channel index
- *
- * This frees allocated memory and removes the cdev that represents this
- * channel in user space.
- */
-static int aim_disconnect_channel(struct most_interface *iface, int channel_id)
-{
-	struct aim_channel *c;
-
-	if (!iface) {
-		pr_info("Bad interface pointer\n");
-		return -EINVAL;
-	}
-
-	c = get_channel(iface, channel_id);
-	if (!c)
-		return -ENXIO;
-
-	mutex_lock(&c->io_mutex);
-	spin_lock(&c->unlink);
-	c->dev = NULL;
-	spin_unlock(&c->unlink);
-	destroy_cdev(c);
-	if (c->access_ref) {
-		stop_channel(c);
-		wake_up_interruptible(&c->wq);
-		mutex_unlock(&c->io_mutex);
-	} else {
-		mutex_unlock(&c->io_mutex);
-		destroy_channel(c);
-	}
-	return 0;
-}
-
-/**
- * aim_rx_completion - completion handler for rx channels
- * @mbo: pointer to buffer object that has completed
- *
- * This searches for the channel linked to this MBO and stores it in the local
- * fifo buffer.
- */
-static int aim_rx_completion(struct mbo *mbo)
-{
-	struct aim_channel *c;
-
-	if (!mbo)
-		return -EINVAL;
-
-	c = get_channel(mbo->ifp, mbo->hdm_channel_id);
-	if (!c)
-		return -ENXIO;
-
-	spin_lock(&c->unlink);
-	if (!c->access_ref || !c->dev) {
-		spin_unlock(&c->unlink);
-		return -ENODEV;
-	}
-	kfifo_in(&c->fifo, &mbo, 1);
-	spin_unlock(&c->unlink);
-#ifdef DEBUG_MESG
-	if (kfifo_is_full(&c->fifo))
-		pr_info("WARN: Fifo is full\n");
-#endif
-	wake_up_interruptible(&c->wq);
-	return 0;
-}
-
-/**
- * aim_tx_completion - completion handler for tx channels
- * @iface: pointer to interface instance
- * @channel_id: channel index/ID
- *
- * This wakes sleeping processes in the wait-queue.
- */
-static int aim_tx_completion(struct most_interface *iface, int channel_id)
-{
-	struct aim_channel *c;
-
-	if (!iface) {
-		pr_info("Bad interface pointer\n");
-		return -EINVAL;
-	}
-	if ((channel_id < 0) || (channel_id >= iface->num_channels)) {
-		pr_info("Channel ID out of range\n");
-		return -EINVAL;
-	}
-
-	c = get_channel(iface, channel_id);
-	if (!c)
-		return -ENXIO;
-	wake_up_interruptible(&c->wq);
-	return 0;
-}
-
-/**
- * aim_probe - probe function of the driver module
- * @iface: pointer to interface instance
- * @channel_id: channel index/ID
- * @cfg: pointer to actual channel configuration
- * @parent: pointer to kobject (needed for sysfs hook-up)
- * @name: name of the device to be created
- *
- * This allocates achannel object and creates the device node in /dev
- *
- * Returns 0 on success or error code otherwise.
- */
-static int aim_probe(struct most_interface *iface, int channel_id,
-		     struct most_channel_config *cfg,
-		     struct kobject *parent, char *name)
-{
-	struct aim_channel *c;
-	unsigned long cl_flags;
-	int retval;
-	int current_minor;
-
-	if ((!iface) || (!cfg) || (!parent) || (!name)) {
-		pr_info("Probing AIM with bad arguments");
-		return -EINVAL;
-	}
-	c = get_channel(iface, channel_id);
-	if (c)
-		return -EEXIST;
-
-	current_minor = ida_simple_get(&minor_id, 0, 0, GFP_KERNEL);
-	if (current_minor < 0)
-		return current_minor;
-
-	c = kzalloc(sizeof(*c), GFP_KERNEL);
-	if (!c) {
-		retval = -ENOMEM;
-		goto error_alloc_channel;
-	}
-
-	c->devno = MKDEV(major, current_minor);
-	cdev_init(&c->cdev, &channel_fops);
-	c->cdev.owner = THIS_MODULE;
-	cdev_add(&c->cdev, c->devno, 1);
-	c->iface = iface;
-	c->cfg = cfg;
-	c->channel_id = channel_id;
-	c->access_ref = 0;
-	spin_lock_init(&c->unlink);
-	INIT_KFIFO(c->fifo);
-	retval = kfifo_alloc(&c->fifo, cfg->num_buffers, GFP_KERNEL);
-	if (retval) {
-		pr_info("failed to alloc channel kfifo");
-		goto error_alloc_kfifo;
-	}
-	init_waitqueue_head(&c->wq);
-	mutex_init(&c->io_mutex);
-	spin_lock_irqsave(&ch_list_lock, cl_flags);
-	list_add_tail(&c->list, &channel_list);
-	spin_unlock_irqrestore(&ch_list_lock, cl_flags);
-	c->dev = device_create(aim_class,
-				     NULL,
-				     c->devno,
-				     NULL,
-				     "%s", name);
-
-	if (IS_ERR(c->dev)) {
-		retval = PTR_ERR(c->dev);
-		pr_info("failed to create new device node %s\n", name);
-		goto error_create_device;
-	}
-	kobject_uevent(&c->dev->kobj, KOBJ_ADD);
-	return 0;
-
-error_create_device:
-	kfifo_free(&c->fifo);
-	list_del(&c->list);
-error_alloc_kfifo:
-	cdev_del(&c->cdev);
-	kfree(c);
-error_alloc_channel:
-	ida_simple_remove(&minor_id, current_minor);
-	return retval;
-}
-
-static struct most_aim cdev_aim = {
-	.name = "cdev",
-	.probe_channel = aim_probe,
-	.disconnect_channel = aim_disconnect_channel,
-	.rx_completion = aim_rx_completion,
-	.tx_completion = aim_tx_completion,
-};
-
-static int __init mod_init(void)
-{
-	int err;
-
-	pr_info("init()\n");
-
-	INIT_LIST_HEAD(&channel_list);
-	spin_lock_init(&ch_list_lock);
-	ida_init(&minor_id);
-
-	err = alloc_chrdev_region(&aim_devno, 0, 50, "cdev");
-	if (err < 0)
-		goto dest_ida;
-	major = MAJOR(aim_devno);
-
-	aim_class = class_create(THIS_MODULE, "most_cdev_aim");
-	if (IS_ERR(aim_class)) {
-		pr_err("no udev support\n");
-		err = PTR_ERR(aim_class);
-		goto free_cdev;
-	}
-	err = most_register_aim(&cdev_aim);
-	if (err)
-		goto dest_class;
-	return 0;
-
-dest_class:
-	class_destroy(aim_class);
-free_cdev:
-	unregister_chrdev_region(aim_devno, 1);
-dest_ida:
-	ida_destroy(&minor_id);
-	return err;
-}
-
-static void __exit mod_exit(void)
-{
-	struct aim_channel *c, *tmp;
-
-	pr_info("exit module\n");
-
-	most_deregister_aim(&cdev_aim);
-
-	list_for_each_entry_safe(c, tmp, &channel_list, list) {
-		destroy_cdev(c);
-		destroy_channel(c);
-	}
-	class_destroy(aim_class);
-	unregister_chrdev_region(aim_devno, 1);
-	ida_destroy(&minor_id);
-}
-
-module_init(mod_init);
-module_exit(mod_exit);
-MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("character device AIM for mostcore");
diff --git a/drivers/staging/most/cdev/Kconfig b/drivers/staging/most/cdev/Kconfig
new file mode 100644
index 0000000000000..2b04e26bcbea3
--- /dev/null
+++ b/drivers/staging/most/cdev/Kconfig
@@ -0,0 +1,12 @@
+#
+# MOST Cdev configuration
+#
+
+config MOST_CDEV
+	tristate "Cdev"
+
+	---help---
+	  Say Y here if you want to commumicate via character devices.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called most_cdev.
diff --git a/drivers/staging/most/cdev/Makefile b/drivers/staging/most/cdev/Makefile
new file mode 100644
index 0000000000000..afb9870eb50f3
--- /dev/null
+++ b/drivers/staging/most/cdev/Makefile
@@ -0,0 +1,4 @@
+obj-$(CONFIG_MOST_CDEV) += most_cdev.o
+
+most_cdev-objs := cdev.o
+ccflags-y += -Idrivers/staging/
diff --git a/drivers/staging/most/cdev/cdev.c b/drivers/staging/most/cdev/cdev.c
new file mode 100644
index 0000000000000..3ae9246c0c5c2
--- /dev/null
+++ b/drivers/staging/most/cdev/cdev.c
@@ -0,0 +1,558 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * cdev.c - Application interfacing module for character devices
+ *
+ * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+#include <linux/poll.h>
+#include <linux/kfifo.h>
+#include <linux/uaccess.h>
+#include <linux/idr.h>
+#include "most/core.h"
+
+static dev_t aim_devno;
+static struct class *aim_class;
+static struct ida minor_id;
+static unsigned int major;
+static struct most_aim cdev_aim;
+
+struct aim_channel {
+	wait_queue_head_t wq;
+	spinlock_t unlink;	/* synchronization lock to unlink channels */
+	struct cdev cdev;
+	struct device *dev;
+	struct mutex io_mutex;
+	struct most_interface *iface;
+	struct most_channel_config *cfg;
+	unsigned int channel_id;
+	dev_t devno;
+	size_t mbo_offs;
+	DECLARE_KFIFO_PTR(fifo, typeof(struct mbo *));
+	int access_ref;
+	struct list_head list;
+};
+
+#define to_channel(d) container_of(d, struct aim_channel, cdev)
+static struct list_head channel_list;
+static spinlock_t ch_list_lock;
+
+static inline bool ch_has_mbo(struct aim_channel *c)
+{
+	return channel_has_mbo(c->iface, c->channel_id, &cdev_aim) > 0;
+}
+
+static inline bool ch_get_mbo(struct aim_channel *c, struct mbo **mbo)
+{
+	if (!kfifo_peek(&c->fifo, mbo)) {
+		*mbo = most_get_mbo(c->iface, c->channel_id, &cdev_aim);
+		if (*mbo)
+			kfifo_in(&c->fifo, mbo, 1);
+	}
+	return *mbo;
+}
+
+static struct aim_channel *get_channel(struct most_interface *iface, int id)
+{
+	struct aim_channel *c, *tmp;
+	unsigned long flags;
+	int found_channel = 0;
+
+	spin_lock_irqsave(&ch_list_lock, flags);
+	list_for_each_entry_safe(c, tmp, &channel_list, list) {
+		if ((c->iface == iface) && (c->channel_id == id)) {
+			found_channel = 1;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&ch_list_lock, flags);
+	if (!found_channel)
+		return NULL;
+	return c;
+}
+
+static void stop_channel(struct aim_channel *c)
+{
+	struct mbo *mbo;
+
+	while (kfifo_out((struct kfifo *)&c->fifo, &mbo, 1))
+		most_put_mbo(mbo);
+	most_stop_channel(c->iface, c->channel_id, &cdev_aim);
+}
+
+static void destroy_cdev(struct aim_channel *c)
+{
+	unsigned long flags;
+
+	device_destroy(aim_class, c->devno);
+	cdev_del(&c->cdev);
+	spin_lock_irqsave(&ch_list_lock, flags);
+	list_del(&c->list);
+	spin_unlock_irqrestore(&ch_list_lock, flags);
+}
+
+static void destroy_channel(struct aim_channel *c)
+{
+	ida_simple_remove(&minor_id, MINOR(c->devno));
+	kfifo_free(&c->fifo);
+	kfree(c);
+}
+
+/**
+ * aim_open - implements the syscall to open the device
+ * @inode: inode pointer
+ * @filp: file pointer
+ *
+ * This stores the channel pointer in the private data field of
+ * the file structure and activates the channel within the core.
+ */
+static int aim_open(struct inode *inode, struct file *filp)
+{
+	struct aim_channel *c;
+	int ret;
+
+	c = to_channel(inode->i_cdev);
+	filp->private_data = c;
+
+	if (((c->cfg->direction == MOST_CH_RX) &&
+	     ((filp->f_flags & O_ACCMODE) != O_RDONLY)) ||
+	     ((c->cfg->direction == MOST_CH_TX) &&
+		((filp->f_flags & O_ACCMODE) != O_WRONLY))) {
+		pr_info("WARN: Access flags mismatch\n");
+		return -EACCES;
+	}
+
+	mutex_lock(&c->io_mutex);
+	if (!c->dev) {
+		pr_info("WARN: Device is destroyed\n");
+		mutex_unlock(&c->io_mutex);
+		return -ENODEV;
+	}
+
+	if (c->access_ref) {
+		pr_info("WARN: Device is busy\n");
+		mutex_unlock(&c->io_mutex);
+		return -EBUSY;
+	}
+
+	c->mbo_offs = 0;
+	ret = most_start_channel(c->iface, c->channel_id, &cdev_aim);
+	if (!ret)
+		c->access_ref = 1;
+	mutex_unlock(&c->io_mutex);
+	return ret;
+}
+
+/**
+ * aim_close - implements the syscall to close the device
+ * @inode: inode pointer
+ * @filp: file pointer
+ *
+ * This stops the channel within the core.
+ */
+static int aim_close(struct inode *inode, struct file *filp)
+{
+	struct aim_channel *c = to_channel(inode->i_cdev);
+
+	mutex_lock(&c->io_mutex);
+	spin_lock(&c->unlink);
+	c->access_ref = 0;
+	spin_unlock(&c->unlink);
+	if (c->dev) {
+		stop_channel(c);
+		mutex_unlock(&c->io_mutex);
+	} else {
+		mutex_unlock(&c->io_mutex);
+		destroy_channel(c);
+	}
+	return 0;
+}
+
+/**
+ * aim_write - implements the syscall to write to the device
+ * @filp: file pointer
+ * @buf: pointer to user buffer
+ * @count: number of bytes to write
+ * @offset: offset from where to start writing
+ */
+static ssize_t aim_write(struct file *filp, const char __user *buf,
+			 size_t count, loff_t *offset)
+{
+	int ret;
+	size_t to_copy, left;
+	struct mbo *mbo = NULL;
+	struct aim_channel *c = filp->private_data;
+
+	mutex_lock(&c->io_mutex);
+	while (c->dev && !ch_get_mbo(c, &mbo)) {
+		mutex_unlock(&c->io_mutex);
+
+		if ((filp->f_flags & O_NONBLOCK))
+			return -EAGAIN;
+		if (wait_event_interruptible(c->wq, ch_has_mbo(c) || !c->dev))
+			return -ERESTARTSYS;
+		mutex_lock(&c->io_mutex);
+	}
+
+	if (unlikely(!c->dev)) {
+		ret = -ENODEV;
+		goto unlock;
+	}
+
+	to_copy = min(count, c->cfg->buffer_size - c->mbo_offs);
+	left = copy_from_user(mbo->virt_address + c->mbo_offs, buf, to_copy);
+	if (left == to_copy) {
+		ret = -EFAULT;
+		goto unlock;
+	}
+
+	c->mbo_offs += to_copy - left;
+	if (c->mbo_offs >= c->cfg->buffer_size ||
+	    c->cfg->data_type == MOST_CH_CONTROL ||
+	    c->cfg->data_type == MOST_CH_ASYNC) {
+		kfifo_skip(&c->fifo);
+		mbo->buffer_length = c->mbo_offs;
+		c->mbo_offs = 0;
+		most_submit_mbo(mbo);
+	}
+
+	ret = to_copy - left;
+unlock:
+	mutex_unlock(&c->io_mutex);
+	return ret;
+}
+
+/**
+ * aim_read - implements the syscall to read from the device
+ * @filp: file pointer
+ * @buf: pointer to user buffer
+ * @count: number of bytes to read
+ * @offset: offset from where to start reading
+ */
+static ssize_t
+aim_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
+{
+	size_t to_copy, not_copied, copied;
+	struct mbo *mbo;
+	struct aim_channel *c = filp->private_data;
+
+	mutex_lock(&c->io_mutex);
+	while (c->dev && !kfifo_peek(&c->fifo, &mbo)) {
+		mutex_unlock(&c->io_mutex);
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+		if (wait_event_interruptible(c->wq,
+					     (!kfifo_is_empty(&c->fifo) ||
+					      (!c->dev))))
+			return -ERESTARTSYS;
+		mutex_lock(&c->io_mutex);
+	}
+
+	/* make sure we don't submit to gone devices */
+	if (unlikely(!c->dev)) {
+		mutex_unlock(&c->io_mutex);
+		return -ENODEV;
+	}
+
+	to_copy = min_t(size_t,
+			count,
+			mbo->processed_length - c->mbo_offs);
+
+	not_copied = copy_to_user(buf,
+				  mbo->virt_address + c->mbo_offs,
+				  to_copy);
+
+	copied = to_copy - not_copied;
+
+	c->mbo_offs += copied;
+	if (c->mbo_offs >= mbo->processed_length) {
+		kfifo_skip(&c->fifo);
+		most_put_mbo(mbo);
+		c->mbo_offs = 0;
+	}
+	mutex_unlock(&c->io_mutex);
+	return copied;
+}
+
+static unsigned int aim_poll(struct file *filp, poll_table *wait)
+{
+	struct aim_channel *c = filp->private_data;
+	unsigned int mask = 0;
+
+	poll_wait(filp, &c->wq, wait);
+
+	if (c->cfg->direction == MOST_CH_RX) {
+		if (!kfifo_is_empty(&c->fifo))
+			mask |= POLLIN | POLLRDNORM;
+	} else {
+		if (!kfifo_is_empty(&c->fifo) || ch_has_mbo(c))
+			mask |= POLLOUT | POLLWRNORM;
+	}
+	return mask;
+}
+
+/**
+ * Initialization of struct file_operations
+ */
+static const struct file_operations channel_fops = {
+	.owner = THIS_MODULE,
+	.read = aim_read,
+	.write = aim_write,
+	.open = aim_open,
+	.release = aim_close,
+	.poll = aim_poll,
+};
+
+/**
+ * aim_disconnect_channel - disconnect a channel
+ * @iface: pointer to interface instance
+ * @channel_id: channel index
+ *
+ * This frees allocated memory and removes the cdev that represents this
+ * channel in user space.
+ */
+static int aim_disconnect_channel(struct most_interface *iface, int channel_id)
+{
+	struct aim_channel *c;
+
+	if (!iface) {
+		pr_info("Bad interface pointer\n");
+		return -EINVAL;
+	}
+
+	c = get_channel(iface, channel_id);
+	if (!c)
+		return -ENXIO;
+
+	mutex_lock(&c->io_mutex);
+	spin_lock(&c->unlink);
+	c->dev = NULL;
+	spin_unlock(&c->unlink);
+	destroy_cdev(c);
+	if (c->access_ref) {
+		stop_channel(c);
+		wake_up_interruptible(&c->wq);
+		mutex_unlock(&c->io_mutex);
+	} else {
+		mutex_unlock(&c->io_mutex);
+		destroy_channel(c);
+	}
+	return 0;
+}
+
+/**
+ * aim_rx_completion - completion handler for rx channels
+ * @mbo: pointer to buffer object that has completed
+ *
+ * This searches for the channel linked to this MBO and stores it in the local
+ * fifo buffer.
+ */
+static int aim_rx_completion(struct mbo *mbo)
+{
+	struct aim_channel *c;
+
+	if (!mbo)
+		return -EINVAL;
+
+	c = get_channel(mbo->ifp, mbo->hdm_channel_id);
+	if (!c)
+		return -ENXIO;
+
+	spin_lock(&c->unlink);
+	if (!c->access_ref || !c->dev) {
+		spin_unlock(&c->unlink);
+		return -ENODEV;
+	}
+	kfifo_in(&c->fifo, &mbo, 1);
+	spin_unlock(&c->unlink);
+#ifdef DEBUG_MESG
+	if (kfifo_is_full(&c->fifo))
+		pr_info("WARN: Fifo is full\n");
+#endif
+	wake_up_interruptible(&c->wq);
+	return 0;
+}
+
+/**
+ * aim_tx_completion - completion handler for tx channels
+ * @iface: pointer to interface instance
+ * @channel_id: channel index/ID
+ *
+ * This wakes sleeping processes in the wait-queue.
+ */
+static int aim_tx_completion(struct most_interface *iface, int channel_id)
+{
+	struct aim_channel *c;
+
+	if (!iface) {
+		pr_info("Bad interface pointer\n");
+		return -EINVAL;
+	}
+	if ((channel_id < 0) || (channel_id >= iface->num_channels)) {
+		pr_info("Channel ID out of range\n");
+		return -EINVAL;
+	}
+
+	c = get_channel(iface, channel_id);
+	if (!c)
+		return -ENXIO;
+	wake_up_interruptible(&c->wq);
+	return 0;
+}
+
+/**
+ * aim_probe - probe function of the driver module
+ * @iface: pointer to interface instance
+ * @channel_id: channel index/ID
+ * @cfg: pointer to actual channel configuration
+ * @parent: pointer to kobject (needed for sysfs hook-up)
+ * @name: name of the device to be created
+ *
+ * This allocates achannel object and creates the device node in /dev
+ *
+ * Returns 0 on success or error code otherwise.
+ */
+static int aim_probe(struct most_interface *iface, int channel_id,
+		     struct most_channel_config *cfg,
+		     struct kobject *parent, char *name)
+{
+	struct aim_channel *c;
+	unsigned long cl_flags;
+	int retval;
+	int current_minor;
+
+	if ((!iface) || (!cfg) || (!parent) || (!name)) {
+		pr_info("Probing AIM with bad arguments");
+		return -EINVAL;
+	}
+	c = get_channel(iface, channel_id);
+	if (c)
+		return -EEXIST;
+
+	current_minor = ida_simple_get(&minor_id, 0, 0, GFP_KERNEL);
+	if (current_minor < 0)
+		return current_minor;
+
+	c = kzalloc(sizeof(*c), GFP_KERNEL);
+	if (!c) {
+		retval = -ENOMEM;
+		goto error_alloc_channel;
+	}
+
+	c->devno = MKDEV(major, current_minor);
+	cdev_init(&c->cdev, &channel_fops);
+	c->cdev.owner = THIS_MODULE;
+	cdev_add(&c->cdev, c->devno, 1);
+	c->iface = iface;
+	c->cfg = cfg;
+	c->channel_id = channel_id;
+	c->access_ref = 0;
+	spin_lock_init(&c->unlink);
+	INIT_KFIFO(c->fifo);
+	retval = kfifo_alloc(&c->fifo, cfg->num_buffers, GFP_KERNEL);
+	if (retval) {
+		pr_info("failed to alloc channel kfifo");
+		goto error_alloc_kfifo;
+	}
+	init_waitqueue_head(&c->wq);
+	mutex_init(&c->io_mutex);
+	spin_lock_irqsave(&ch_list_lock, cl_flags);
+	list_add_tail(&c->list, &channel_list);
+	spin_unlock_irqrestore(&ch_list_lock, cl_flags);
+	c->dev = device_create(aim_class,
+				     NULL,
+				     c->devno,
+				     NULL,
+				     "%s", name);
+
+	if (IS_ERR(c->dev)) {
+		retval = PTR_ERR(c->dev);
+		pr_info("failed to create new device node %s\n", name);
+		goto error_create_device;
+	}
+	kobject_uevent(&c->dev->kobj, KOBJ_ADD);
+	return 0;
+
+error_create_device:
+	kfifo_free(&c->fifo);
+	list_del(&c->list);
+error_alloc_kfifo:
+	cdev_del(&c->cdev);
+	kfree(c);
+error_alloc_channel:
+	ida_simple_remove(&minor_id, current_minor);
+	return retval;
+}
+
+static struct most_aim cdev_aim = {
+	.name = "cdev",
+	.probe_channel = aim_probe,
+	.disconnect_channel = aim_disconnect_channel,
+	.rx_completion = aim_rx_completion,
+	.tx_completion = aim_tx_completion,
+};
+
+static int __init mod_init(void)
+{
+	int err;
+
+	pr_info("init()\n");
+
+	INIT_LIST_HEAD(&channel_list);
+	spin_lock_init(&ch_list_lock);
+	ida_init(&minor_id);
+
+	err = alloc_chrdev_region(&aim_devno, 0, 50, "cdev");
+	if (err < 0)
+		goto dest_ida;
+	major = MAJOR(aim_devno);
+
+	aim_class = class_create(THIS_MODULE, "most_cdev_aim");
+	if (IS_ERR(aim_class)) {
+		pr_err("no udev support\n");
+		err = PTR_ERR(aim_class);
+		goto free_cdev;
+	}
+	err = most_register_aim(&cdev_aim);
+	if (err)
+		goto dest_class;
+	return 0;
+
+dest_class:
+	class_destroy(aim_class);
+free_cdev:
+	unregister_chrdev_region(aim_devno, 1);
+dest_ida:
+	ida_destroy(&minor_id);
+	return err;
+}
+
+static void __exit mod_exit(void)
+{
+	struct aim_channel *c, *tmp;
+
+	pr_info("exit module\n");
+
+	most_deregister_aim(&cdev_aim);
+
+	list_for_each_entry_safe(c, tmp, &channel_list, list) {
+		destroy_cdev(c);
+		destroy_channel(c);
+	}
+	class_destroy(aim_class);
+	unregister_chrdev_region(aim_devno, 1);
+	ida_destroy(&minor_id);
+}
+
+module_init(mod_init);
+module_exit(mod_exit);
+MODULE_AUTHOR("Christian Gromm <christian.gromm@microchip.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("character device AIM for mostcore");