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authorJan-Simon Möller <jsmoeller@linuxfoundation.org>2015-12-22 00:46:19 +0100
committerJan-Simon Möller <jsmoeller@linuxfoundation.org>2015-12-22 00:48:01 +0100
commitdf9e0ad632b122e19964d2f39588fb5fe2087037 (patch)
treef896d3cefff09a33ff87f0dafe61db7c3c7ab9b3 /recipes-kernel/aim-cdev/files/cdev.c
parente10617b85d81591de2a5b567d43a1f48cc15aa5f (diff)
parent762181dff011efbaf3d40edb1b3d573c5aceab01 (diff)
Merge branch 'master' of ssh://gerrit.automotivelinux.org:29418/AGL/meta-agl-demo into albacore
Change-Id: Ieedfdda7a1be86c626c6f67b57fed05adb628a87 Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>
Diffstat (limited to 'recipes-kernel/aim-cdev/files/cdev.c')
-rw-r--r--recipes-kernel/aim-cdev/files/cdev.c550
1 files changed, 550 insertions, 0 deletions
diff --git a/recipes-kernel/aim-cdev/files/cdev.c b/recipes-kernel/aim-cdev/files/cdev.c
new file mode 100644
index 000000000..3a2dbf149
--- /dev/null
+++ b/recipes-kernel/aim-cdev/files/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);
+
+ retval = IS_ERR(c->dev);
+ if (retval) {
+ 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");