linux/drivers/most/most_cdev.c

// SPDX-License-Identifier: GPL-2.0
/*
 * cdev.c - Character device component for Mostcore
 *
 * Copyright (C) 2013-2015 Microchip Technology Germany II GmbH & Co. KG
 */

#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 <linux/most.h>

#define CHRDEV_REGION_SIZE …

static struct cdev_component { … } comp;

struct comp_channel { … };

#define to_channel(d) …
static LIST_HEAD(channel_list);
static DEFINE_SPINLOCK(ch_list_lock);

static inline bool ch_has_mbo(struct comp_channel *c)
{ … }

static inline struct mbo *ch_get_mbo(struct comp_channel *c, struct mbo **mbo)
{ … }

static struct comp_channel *get_channel(struct most_interface *iface, int id)
{ … }

static void stop_channel(struct comp_channel *c)
{ … }

static void destroy_cdev(struct comp_channel *c)
{ … }

static void destroy_channel(struct comp_channel *c)
{ … }

/**
 * comp_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 comp_open(struct inode *inode, struct file *filp)
{ … }

/**
 * comp_close - implements the syscall to close the device
 * @inode: inode pointer
 * @filp: file pointer
 *
 * This stops the channel within the core.
 */
static int comp_close(struct inode *inode, struct file *filp)
{ … }

/**
 * comp_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 comp_write(struct file *filp, const char __user *buf,
			  size_t count, loff_t *offset)
{ … }

/**
 * comp_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
comp_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
{ … }

static __poll_t comp_poll(struct file *filp, poll_table *wait)
{ … }

/*
 * Initialization of struct file_operations
 */
static const struct file_operations channel_fops = …;

/**
 * comp_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 comp_disconnect_channel(struct most_interface *iface, int channel_id)
{ … }

/**
 * comp_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 comp_rx_completion(struct mbo *mbo)
{ … }

/**
 * comp_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 comp_tx_completion(struct most_interface *iface, int channel_id)
{ … }

/**
 * comp_probe - probe function of the driver module
 * @iface: pointer to interface instance
 * @channel_id: channel index/ID
 * @cfg: pointer to actual channel configuration
 * @name: name of the device to be created
 * @args: pointer to array of component parameters (from configfs)
 *
 * This allocates a channel object and creates the device node in /dev
 *
 * Returns 0 on success or error code otherwise.
 */
static int comp_probe(struct most_interface *iface, int channel_id,
		      struct most_channel_config *cfg, char *name, char *args)
{ … }

static struct cdev_component comp = …;

static int __init most_cdev_init(void)
{ … }

static void __exit most_cdev_exit(void)
{ … }

module_init(…) …;
module_exit(most_cdev_exit);
MODULE_AUTHOR(…) …;
MODULE_LICENSE(…) …;
MODULE_DESCRIPTION(…) …;