diff options
Diffstat (limited to 'recipes-kernel/aim-cdev')
| -rw-r--r-- | recipes-kernel/aim-cdev/aim-cdev.bb | 21 | ||||
| -rw-r--r-- | recipes-kernel/aim-cdev/files/COPYING | 340 | ||||
| -rw-r--r-- | recipes-kernel/aim-cdev/files/Makefile | 18 | ||||
| -rw-r--r-- | recipes-kernel/aim-cdev/files/cdev.c | 550 |
4 files changed, 929 insertions, 0 deletions
diff --git a/recipes-kernel/aim-cdev/aim-cdev.bb b/recipes-kernel/aim-cdev/aim-cdev.bb new file mode 100644 index 000000000..e2b0bbef4 --- /dev/null +++ b/recipes-kernel/aim-cdev/aim-cdev.bb @@ -0,0 +1,21 @@ +DESCRIPTION = "Example of how to build an external Linux kernel module" +LICENSE = "GPLv2" +LIC_FILES_CHKSUM = "file://COPYING;md5=12f884d2ae1ff87c09e5b7ccc2c4ca7e \ + file://cdev.c;md5=b080105073061d6c4f25e3c2daab2d12 \ + " + +inherit module + +PR = "r0" +PV = "0.1" + +SRC_URI = "file://Makefile \ + file://../../mostcore/files/mostcore.h \ + file://cdev.c \ + file://COPYING \ + " + +S = "${WORKDIR}" + +# The inherit of module.bbclass will automatically name module packages with +# "kernel-module-" prefix as required by the oe-core build environment. diff --git a/recipes-kernel/aim-cdev/files/COPYING b/recipes-kernel/aim-cdev/files/COPYING new file mode 100644 index 000000000..6d45519c8 --- /dev/null +++ b/recipes-kernel/aim-cdev/files/COPYING @@ -0,0 +1,340 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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If this is what you want to do, use the GNU Library General +Public License instead of this License. diff --git a/recipes-kernel/aim-cdev/files/Makefile b/recipes-kernel/aim-cdev/files/Makefile new file mode 100644 index 000000000..05853c266 --- /dev/null +++ b/recipes-kernel/aim-cdev/files/Makefile @@ -0,0 +1,18 @@ +# Makefile +# + +SRC := $(shell pwd) + +obj-m += aim_cdev.o +aim_cdev-y := cdev.o +CFLAGS_cdev.o := -I$(src)/../../mostcore/files/ + +all: + $(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules + +modules_install: + $(MAKE) -C $(KERNEL_SRC) M=$(SRC) modules_install + +clean: + $(MAKE) -C $(KERNEL_SRC) M=$(SRC) clean + 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"); |