--- /dev/null
+/*
+ * 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;
+
+
+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);
+ kfree(channel);
+ ida_simple_remove(&minor_id, MINOR(channel->devno));
+ wake_up_interruptible(&channel->wq);
+ 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:
+ 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.
+ */
+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.
+ */
+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.
+ */
+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;
+}
+
+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.
+ */
+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;
+}
+
+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");
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff