add MOST-Linux-Driver sources

This patch adds the sources of the MOST-Linux-Driver to AGL's /src
directory.
Gitlab commit: b0ab66aac15096ed7701b95ffc188bcceb71e55b

Change-Id: I82a57f1c0b605aa8d5e320eb8f14ad932603f63b
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>

1 files changed, 550 insertions, 0 deletions

diff --git a/driver/aim-cdev/cdev.c b/driver/aim-cdev/cdev.c
new file mode 100644
index 0000000..de4f76a
--- /dev/null
+++ b/driver/aim-cdev/cdev.c
@@ -0,0 +1,550 @@
+/*
+ * 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/poll.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;
+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)
+{
+	*mbo = most_get_mbo(c->iface, c->channel_id, &cdev_aim);
+	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);
+	kfifo_free(&c->fifo);
+	spin_lock_irqsave(&ch_list_lock, flags);
+	list_del(&c->list);
+	spin_unlock_irqrestore(&ch_list_lock, flags);
+	ida_simple_remove(&minor_id, MINOR(c->devno));
+}
+
+/**
+ * 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 -EBUSY;
+	}
+
+	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 {
+		destroy_cdev(c);
+		mutex_unlock(&c->io_mutex);
+		kfree(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 actual_len;
+	size_t max_len;
+	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 = -EPIPE;
+		goto unlock;
+	}
+
+	max_len = c->cfg->buffer_size;
+	actual_len = min(count, max_len);
+	mbo->buffer_length = actual_len;
+
+	if (copy_from_user(mbo->virt_address, buf, mbo->buffer_length)) {
+		ret = -EFAULT;
+		goto put_mbo;
+	}
+
+	ret = most_submit_mbo(mbo);
+	if (ret)
+		goto put_mbo;
+
+	mutex_unlock(&c->io_mutex);
+	return actual_len;
+put_mbo:
+	most_put_mbo(mbo);
+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 -EIO;
+	}
+
+	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 (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);
+	if (c->access_ref) {
+		stop_channel(c);
+		wake_up_interruptible(&c->wq);
+		mutex_unlock(&c->io_mutex);
+	} else {
+		destroy_cdev(c);
+		mutex_unlock(&c->io_mutex);
+		kfree(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 -EFAULT;
+	}
+	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)
+{
+	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 *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);
+		kfree(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");