1 files changed, 528 insertions, 0 deletions
diff --git a/drivers/staging/most/aim-cdev/cdev.c b/drivers/staging/most/aim-cdev/cdev.c
new file mode 100644
index 000000000000..0a13d8d0fa39
--- /dev/null
+++ b/drivers/staging/most/aim-cdev/cdev.c
@@ -0,0 +1,528 @@
+/*
+ * cdev.c - Application interfacing module for character devices
+ *
+ * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
+ *
+ * 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.
+ *
+ * This file is licensed under GPLv2.
+ */
+
+#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/kfifo.h>
+#include <linux/uaccess.h>
+#include <linux/idr.h>
+#include "mostcore.h"
+
+static dev_t aim_devno;
+static struct class *aim_class;
+static struct ida minor_id;
+static unsigned int major;
+
+struct aim_channel {
+	wait_queue_head_t wq;
+	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;
+	bool keep_mbo;
+	unsigned int mbo_offs;
+	struct mbo *stacked_mbo;
+	DECLARE_KFIFO_PTR(fifo, typeof(struct mbo *));
+	atomic_t 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 struct aim_channel *get_channel(struct most_interface *iface, int id)
+{
+	struct aim_channel *channel, *tmp;
+	unsigned long flags;
+	int found_channel = 0;
+
+	spin_lock_irqsave(&ch_list_lock, flags);
+	list_for_each_entry_safe(channel, tmp, &channel_list, list) {
+		if ((channel->iface == iface) && (channel->channel_id == id)) {
+			found_channel = 1;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&ch_list_lock, flags);
+	if (!found_channel)
+		return NULL;
+	return channel;
+}
+
+/**
+ * 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 *channel;
+	int ret;
+
+	channel = to_channel(inode->i_cdev);
+	filp->private_data = channel;
+
+	if (((channel->cfg->direction == MOST_CH_RX) &&
+	     ((filp->f_flags & O_ACCMODE) != O_RDONLY))
+	    || ((channel->cfg->direction == MOST_CH_TX) &&
+		((filp->f_flags & O_ACCMODE) != O_WRONLY))) {
+		pr_info("WARN: Access flags mismatch\n");
+		return -EACCES;
+	}
+	if (!atomic_inc_and_test(&channel->access_ref)) {
+		pr_info("WARN: Device is busy\n");
+		atomic_dec(&channel->access_ref);
+		return -EBUSY;
+	}
+
+	ret = most_start_channel(channel->iface, channel->channel_id);
+	if (ret)
+		atomic_dec(&channel->access_ref);
+	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)
+{
+	int ret;
+	struct mbo *mbo;
+	struct aim_channel *channel = to_channel(inode->i_cdev);
+
+	mutex_lock(&channel->io_mutex);
+	if (!channel->dev) {
+		mutex_unlock(&channel->io_mutex);
+		atomic_dec(&channel->access_ref);
+		device_destroy(aim_class, channel->devno);
+		cdev_del(&channel->cdev);
+		kfifo_free(&channel->fifo);
+		list_del(&channel->list);
+		ida_simple_remove(&minor_id, MINOR(channel->devno));
+		wake_up_interruptible(&channel->wq);
+		kfree(channel);
+		return 0;
+	}
+	mutex_unlock(&channel->io_mutex);
+
+	while (0 != kfifo_out((struct kfifo *)&channel->fifo, &mbo, 1))
+		most_put_mbo(mbo);
+	if (channel->keep_mbo == true)
+		most_put_mbo(channel->stacked_mbo);
+	ret = most_stop_channel(channel->iface, channel->channel_id);
+	atomic_dec(&channel->access_ref);
+	wake_up_interruptible(&channel->wq);
+	return ret;
+}
+
+/**
+ * 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, err;
+	size_t actual_len = 0;
+	size_t max_len = 0;
+	ssize_t retval;
+	struct mbo *mbo;
+	struct aim_channel *channel = filp->private_data;
+
+	mutex_lock(&channel->io_mutex);
+	if (unlikely(!channel->dev)) {
+		mutex_unlock(&channel->io_mutex);
+		return -EPIPE;
+	}
+	mutex_unlock(&channel->io_mutex);
+
+	mbo = most_get_mbo(channel->iface, channel->channel_id);
+
+	if (!mbo && channel->dev) {
+		if ((filp->f_flags & O_NONBLOCK))
+			return -EAGAIN;
+		if (wait_event_interruptible(
+			    channel->wq,
+			    (mbo = most_get_mbo(channel->iface,
+						channel->channel_id)) ||
+			    (channel->dev == NULL)))
+			return -ERESTARTSYS;
+	}
+
+	mutex_lock(&channel->io_mutex);
+	if (unlikely(!channel->dev)) {
+		mutex_unlock(&channel->io_mutex);
+		err = -EPIPE;
+		goto error;
+	}
+	mutex_unlock(&channel->io_mutex);
+
+	max_len = channel->cfg->buffer_size;
+	actual_len = min(count, max_len);
+	mbo->buffer_length = actual_len;
+
+	retval = copy_from_user(mbo->virt_address, buf, mbo->buffer_length);
+	if (retval) {
+		err = -EIO;
+		goto error;
+	}
+
+	ret = most_submit_mbo(mbo);
+	if (ret) {
+		pr_info("submitting MBO to core failed\n");
+		err = ret;
+		goto error;
+	}
+	return actual_len - retval;
+error:
+	if (mbo)
+		most_put_mbo(mbo);
+	return err;
+}
+
+/**
+ * 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)
+{
+	ssize_t retval;
+	size_t not_copied, proc_len;
+	struct mbo *mbo;
+	struct aim_channel *channel = filp->private_data;
+
+	if (channel->keep_mbo == true) {
+		mbo = channel->stacked_mbo;
+		channel->keep_mbo = false;
+		goto start_copy;
+	}
+	while ((0 == kfifo_out(&channel->fifo, &mbo, 1))
+	       && (channel->dev != NULL)) {
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+		if (wait_event_interruptible(channel->wq,
+					     (!kfifo_is_empty(&channel->fifo) ||
+					      (channel->dev == NULL))))
+			return -ERESTARTSYS;
+	}
+
+start_copy:
+	/* make sure we don't submit to gone devices */
+	mutex_lock(&channel->io_mutex);
+	if (unlikely(!channel->dev)) {
+		mutex_unlock(&channel->io_mutex);
+		return -EIO;
+	}
+
+	if (count < mbo->processed_length)
+		channel->keep_mbo = true;
+
+	proc_len = min((int)count,
+		       (int)(mbo->processed_length - channel->mbo_offs));
+
+	not_copied = copy_to_user(buf,
+				  mbo->virt_address + channel->mbo_offs,
+				  proc_len);
+
+	retval = not_copied ? proc_len - not_copied : proc_len;
+
+	if (channel->keep_mbo == true) {
+		channel->mbo_offs = retval;
+		channel->stacked_mbo = mbo;
+	} else {
+		most_put_mbo(mbo);
+		channel->mbo_offs = 0;
+	}
+	mutex_unlock(&channel->io_mutex);
+	return retval;
+}
+
+/**
+ * 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,
+};
+
+/**
+ * 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 *channel;
+	unsigned long flags;
+
+	if (!iface) {
+		pr_info("Bad interface pointer\n");
+		return -EINVAL;
+	}
+
+	channel = get_channel(iface, channel_id);
+	if (channel == NULL)
+		return -ENXIO;
+
+	mutex_lock(&channel->io_mutex);
+	channel->dev = NULL;
+	mutex_unlock(&channel->io_mutex);
+
+	if (atomic_read(&channel->access_ref)) {
+		device_destroy(aim_class, channel->devno);
+		cdev_del(&channel->cdev);
+		kfifo_free(&channel->fifo);
+		ida_simple_remove(&minor_id, MINOR(channel->devno));
+		spin_lock_irqsave(&ch_list_lock, flags);
+		list_del(&channel->list);
+		spin_unlock_irqrestore(&ch_list_lock, flags);
+		kfree(channel);
+	} else {
+		wake_up_interruptible(&channel->wq);
+	}
+	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 *channel;
+
+	if (!mbo)
+		return -EINVAL;
+
+	channel = get_channel(mbo->ifp, mbo->hdm_channel_id);
+	if (channel == NULL)
+		return -ENXIO;
+
+	kfifo_in(&channel->fifo, &mbo, 1);
+#ifdef DEBUG_MESG
+	if (kfifo_is_full(&channel->fifo))
+		pr_info("WARN: Fifo is full\n");
+#endif
+	wake_up_interruptible(&channel->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 *channel;
+
+	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;
+	}
+
+	channel = get_channel(iface, channel_id);
+	if (channel == NULL)
+		return -ENXIO;
+	wake_up_interruptible(&channel->wq);
+	return 0;
+}
+
+static struct most_aim cdev_aim;
+
+/**
+ * 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 *channel;
+	unsigned long cl_flags;
+	int retval;
+	int current_minor;
+
+	if ((!iface) || (!cfg) || (!parent) || (!name)) {
+		pr_info("Probing AIM with bad arguments");
+		return -EINVAL;
+	}
+	channel = get_channel(iface, channel_id);
+	if (channel)
+		return -EEXIST;
+
+	current_minor = ida_simple_get(&minor_id, 0, 0, GFP_KERNEL);
+	if (current_minor < 0)
+		return current_minor;
+
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel) {
+		pr_info("failed to alloc channel object\n");
+		retval = -ENOMEM;
+		goto error_alloc_channel;
+	}
+
+	channel->devno = MKDEV(major, current_minor);
+	cdev_init(&channel->cdev, &channel_fops);
+	channel->cdev.owner = THIS_MODULE;
+	cdev_add(&channel->cdev, channel->devno, 1);
+	channel->iface = iface;
+	channel->cfg = cfg;
+	channel->channel_id = channel_id;
+	channel->mbo_offs = 0;
+	atomic_set(&channel->access_ref, -1);
+	INIT_KFIFO(channel->fifo);
+	retval = kfifo_alloc(&channel->fifo, cfg->num_buffers, GFP_KERNEL);
+	if (retval) {
+		pr_info("failed to alloc channel kfifo");
+		goto error_alloc_kfifo;
+	}
+	init_waitqueue_head(&channel->wq);
+	mutex_init(&channel->io_mutex);
+	spin_lock_irqsave(&ch_list_lock, cl_flags);
+	list_add_tail(&channel->list, &channel_list);
+	spin_unlock_irqrestore(&ch_list_lock, cl_flags);
+	channel->dev = device_create(aim_class,
+				     NULL,
+				     channel->devno,
+				     NULL,
+				     "%s", name);
+
+	retval = IS_ERR(channel->dev);
+	if (retval) {
+		pr_info("failed to create new device node %s\n", name);
+		goto error_create_device;
+	}
+	kobject_uevent(&channel->dev->kobj, KOBJ_ADD);
+	return 0;
+
+error_create_device:
+	kfifo_free(&channel->fifo);
+	list_del(&channel->list);
+error_alloc_kfifo:
+	cdev_del(&channel->cdev);
+	kfree(channel);
+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)
+{
+	pr_info("init()\n");
+
+	INIT_LIST_HEAD(&channel_list);
+	spin_lock_init(&ch_list_lock);
+	ida_init(&minor_id);
+
+	if (alloc_chrdev_region(&aim_devno, 0, 50, "cdev") < 0)
+		return -EIO;
+	major = MAJOR(aim_devno);
+
+	aim_class = class_create(THIS_MODULE, "most_cdev_aim");
+	if (IS_ERR(aim_class)) {
+		pr_err("no udev support\n");
+		goto free_cdev;
+	}
+
+	if (most_register_aim(&cdev_aim))
+		goto dest_class;
+	return 0;
+
+dest_class:
+	class_destroy(aim_class);
+free_cdev:
+	unregister_chrdev_region(aim_devno, 1);
+	return -EIO;
+}
+
+static void __exit mod_exit(void)
+{
+	struct aim_channel *channel, *tmp;
+
+	pr_info("exit module\n");
+
+	most_deregister_aim(&cdev_aim);
+
+	list_for_each_entry_safe(channel, tmp, &channel_list, list) {
+		device_destroy(aim_class, channel->devno);
+		cdev_del(&channel->cdev);
+		kfifo_free(&channel->fifo);
+		list_del(&channel->list);
+		ida_simple_remove(&minor_id, MINOR(channel->devno));
+		kfree(channel);
+	}
+	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");