// SPDX-License-Identifier: GPL-2.0-only
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/*
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* cec-core.c - HDMI Consumer Electronics Control framework - Core
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*
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* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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*/
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/kmod.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include "cec-priv.h"
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#define CEC_NUM_DEVICES 256
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#define CEC_NAME "cec"
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int cec_debug;
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module_param_named(debug, cec_debug, int, 0644);
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MODULE_PARM_DESC(debug, "debug level (0-2)");
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static bool debug_phys_addr;
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module_param(debug_phys_addr, bool, 0644);
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MODULE_PARM_DESC(debug_phys_addr, "add CEC_CAP_PHYS_ADDR if set");
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static dev_t cec_dev_t;
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/* Active devices */
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static DEFINE_MUTEX(cec_devnode_lock);
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static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);
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static struct dentry *top_cec_dir;
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/* dev to cec_devnode */
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#define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)
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int cec_get_device(struct cec_devnode *devnode)
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{
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/*
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* Check if the cec device is available. This needs to be done with
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* the devnode->lock held to prevent an open/unregister race:
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* without the lock, the device could be unregistered and freed between
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* the devnode->registered check and get_device() calls, leading to
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* a crash.
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*/
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mutex_lock(&devnode->lock);
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/*
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* return ENXIO if the cec device has been removed
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* already or if it is not registered anymore.
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*/
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if (!devnode->registered) {
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mutex_unlock(&devnode->lock);
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return -ENXIO;
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}
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/* and increase the device refcount */
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get_device(&devnode->dev);
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mutex_unlock(&devnode->lock);
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return 0;
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}
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void cec_put_device(struct cec_devnode *devnode)
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{
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put_device(&devnode->dev);
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}
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/* Called when the last user of the cec device exits. */
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static void cec_devnode_release(struct device *cd)
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{
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struct cec_devnode *devnode = to_cec_devnode(cd);
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mutex_lock(&cec_devnode_lock);
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/* Mark device node number as free */
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clear_bit(devnode->minor, cec_devnode_nums);
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mutex_unlock(&cec_devnode_lock);
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cec_delete_adapter(to_cec_adapter(devnode));
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}
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static struct bus_type cec_bus_type = {
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.name = CEC_NAME,
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};
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/*
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* Register a cec device node
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*
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* The registration code assigns minor numbers and registers the new device node
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* with the kernel. An error is returned if no free minor number can be found,
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* or if the registration of the device node fails.
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*
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* Zero is returned on success.
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*
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* Note that if the cec_devnode_register call fails, the release() callback of
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* the cec_devnode structure is *not* called, so the caller is responsible for
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* freeing any data.
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*/
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static int __must_check cec_devnode_register(struct cec_devnode *devnode,
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struct module *owner)
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{
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int minor;
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int ret;
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/* Part 1: Find a free minor number */
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mutex_lock(&cec_devnode_lock);
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minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
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if (minor == CEC_NUM_DEVICES) {
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mutex_unlock(&cec_devnode_lock);
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pr_err("could not get a free minor\n");
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return -ENFILE;
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}
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set_bit(minor, cec_devnode_nums);
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mutex_unlock(&cec_devnode_lock);
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devnode->minor = minor;
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devnode->dev.bus = &cec_bus_type;
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devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
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devnode->dev.release = cec_devnode_release;
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dev_set_name(&devnode->dev, "cec%d", devnode->minor);
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device_initialize(&devnode->dev);
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/* Part 2: Initialize and register the character device */
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cdev_init(&devnode->cdev, &cec_devnode_fops);
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devnode->cdev.owner = owner;
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kobject_set_name(&devnode->cdev.kobj, "cec%d", devnode->minor);
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devnode->registered = true;
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ret = cdev_device_add(&devnode->cdev, &devnode->dev);
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if (ret) {
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devnode->registered = false;
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pr_err("%s: cdev_device_add failed\n", __func__);
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goto clr_bit;
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}
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return 0;
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clr_bit:
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mutex_lock(&cec_devnode_lock);
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clear_bit(devnode->minor, cec_devnode_nums);
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mutex_unlock(&cec_devnode_lock);
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return ret;
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}
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/*
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* Unregister a cec device node
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*
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* This unregisters the passed device. Future open calls will be met with
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* errors.
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*
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* This function can safely be called if the device node has never been
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* registered or has already been unregistered.
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*/
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static void cec_devnode_unregister(struct cec_adapter *adap)
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{
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struct cec_devnode *devnode = &adap->devnode;
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struct cec_fh *fh;
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mutex_lock(&devnode->lock);
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/* Check if devnode was never registered or already unregistered */
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if (!devnode->registered || devnode->unregistered) {
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mutex_unlock(&devnode->lock);
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return;
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}
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list_for_each_entry(fh, &devnode->fhs, list)
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wake_up_interruptible(&fh->wait);
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devnode->registered = false;
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devnode->unregistered = true;
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mutex_unlock(&devnode->lock);
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mutex_lock(&adap->lock);
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__cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
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__cec_s_log_addrs(adap, NULL, false);
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mutex_unlock(&adap->lock);
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cdev_device_del(&devnode->cdev, &devnode->dev);
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put_device(&devnode->dev);
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}
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#ifdef CONFIG_DEBUG_FS
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static ssize_t cec_error_inj_write(struct file *file,
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const char __user *ubuf, size_t count, loff_t *ppos)
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{
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struct seq_file *sf = file->private_data;
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struct cec_adapter *adap = sf->private;
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char *buf;
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char *line;
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char *p;
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buf = memdup_user_nul(ubuf, min_t(size_t, PAGE_SIZE, count));
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if (IS_ERR(buf))
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return PTR_ERR(buf);
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p = buf;
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while (p && *p) {
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p = skip_spaces(p);
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line = strsep(&p, "\n");
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if (!*line || *line == '#')
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continue;
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if (!adap->ops->error_inj_parse_line(adap, line)) {
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kfree(buf);
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return -EINVAL;
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}
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}
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kfree(buf);
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return count;
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}
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static int cec_error_inj_show(struct seq_file *sf, void *unused)
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{
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struct cec_adapter *adap = sf->private;
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return adap->ops->error_inj_show(adap, sf);
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}
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static int cec_error_inj_open(struct inode *inode, struct file *file)
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{
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return single_open(file, cec_error_inj_show, inode->i_private);
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}
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static const struct file_operations cec_error_inj_fops = {
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.open = cec_error_inj_open,
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.write = cec_error_inj_write,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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#endif
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struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
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void *priv, const char *name, u32 caps,
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u8 available_las)
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{
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struct cec_adapter *adap;
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int res;
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#ifndef CONFIG_MEDIA_CEC_RC
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caps &= ~CEC_CAP_RC;
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#endif
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if (WARN_ON(!caps))
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return ERR_PTR(-EINVAL);
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if (WARN_ON(!ops))
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return ERR_PTR(-EINVAL);
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if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
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return ERR_PTR(-EINVAL);
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adap = kzalloc(sizeof(*adap), GFP_KERNEL);
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if (!adap)
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return ERR_PTR(-ENOMEM);
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strscpy(adap->name, name, sizeof(adap->name));
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adap->phys_addr = CEC_PHYS_ADDR_INVALID;
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adap->cec_pin_is_high = true;
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adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
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adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
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adap->capabilities = caps;
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if (debug_phys_addr)
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adap->capabilities |= CEC_CAP_PHYS_ADDR;
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adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD;
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adap->available_log_addrs = available_las;
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adap->sequence = 0;
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adap->ops = ops;
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adap->priv = priv;
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mutex_init(&adap->lock);
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INIT_LIST_HEAD(&adap->transmit_queue);
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INIT_LIST_HEAD(&adap->wait_queue);
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init_waitqueue_head(&adap->kthread_waitq);
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/* adap->devnode initialization */
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INIT_LIST_HEAD(&adap->devnode.fhs);
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mutex_init(&adap->devnode.lock);
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adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
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if (IS_ERR(adap->kthread)) {
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pr_err("cec-%s: kernel_thread() failed\n", name);
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res = PTR_ERR(adap->kthread);
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kfree(adap);
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return ERR_PTR(res);
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}
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#ifdef CONFIG_MEDIA_CEC_RC
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if (!(caps & CEC_CAP_RC))
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return adap;
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/* Prepare the RC input device */
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adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE);
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if (!adap->rc) {
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pr_err("cec-%s: failed to allocate memory for rc_dev\n",
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name);
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kthread_stop(adap->kthread);
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kfree(adap);
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return ERR_PTR(-ENOMEM);
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}
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snprintf(adap->input_phys, sizeof(adap->input_phys),
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"%s/input0", adap->name);
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adap->rc->device_name = adap->name;
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adap->rc->input_phys = adap->input_phys;
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adap->rc->input_id.bustype = BUS_CEC;
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adap->rc->input_id.vendor = 0;
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adap->rc->input_id.product = 0;
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adap->rc->input_id.version = 1;
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adap->rc->driver_name = CEC_NAME;
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adap->rc->allowed_protocols = RC_PROTO_BIT_CEC;
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adap->rc->priv = adap;
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adap->rc->map_name = RC_MAP_CEC;
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adap->rc->timeout = MS_TO_US(550);
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#endif
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return adap;
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}
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EXPORT_SYMBOL_GPL(cec_allocate_adapter);
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int cec_register_adapter(struct cec_adapter *adap,
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struct device *parent)
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{
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int res;
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if (IS_ERR_OR_NULL(adap))
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return 0;
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if (WARN_ON(!parent))
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return -EINVAL;
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adap->owner = parent->driver->owner;
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adap->devnode.dev.parent = parent;
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#ifdef CONFIG_MEDIA_CEC_RC
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if (adap->capabilities & CEC_CAP_RC) {
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adap->rc->dev.parent = parent;
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res = rc_register_device(adap->rc);
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if (res) {
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pr_err("cec-%s: failed to prepare input device\n",
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adap->name);
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rc_free_device(adap->rc);
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adap->rc = NULL;
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return res;
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}
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}
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#endif
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res = cec_devnode_register(&adap->devnode, adap->owner);
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if (res) {
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#ifdef CONFIG_MEDIA_CEC_RC
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/* Note: rc_unregister also calls rc_free */
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rc_unregister_device(adap->rc);
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adap->rc = NULL;
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#endif
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return res;
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}
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dev_set_drvdata(&adap->devnode.dev, adap);
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#ifdef CONFIG_DEBUG_FS
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if (!top_cec_dir)
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return 0;
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adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev),
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top_cec_dir);
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debugfs_create_devm_seqfile(&adap->devnode.dev, "status", adap->cec_dir,
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cec_adap_status);
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if (!adap->ops->error_inj_show || !adap->ops->error_inj_parse_line)
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return 0;
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debugfs_create_file("error-inj", 0644, adap->cec_dir, adap,
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&cec_error_inj_fops);
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#endif
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return 0;
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}
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EXPORT_SYMBOL_GPL(cec_register_adapter);
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void cec_unregister_adapter(struct cec_adapter *adap)
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{
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if (IS_ERR_OR_NULL(adap))
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return;
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#ifdef CONFIG_MEDIA_CEC_RC
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/* Note: rc_unregister also calls rc_free */
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rc_unregister_device(adap->rc);
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adap->rc = NULL;
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#endif
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debugfs_remove_recursive(adap->cec_dir);
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#ifdef CONFIG_CEC_NOTIFIER
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cec_notifier_cec_adap_unregister(adap->notifier, adap);
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#endif
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cec_devnode_unregister(adap);
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}
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EXPORT_SYMBOL_GPL(cec_unregister_adapter);
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void cec_delete_adapter(struct cec_adapter *adap)
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{
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if (IS_ERR_OR_NULL(adap))
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return;
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if (adap->kthread_config)
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kthread_stop(adap->kthread_config);
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kthread_stop(adap->kthread);
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if (adap->ops->adap_free)
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adap->ops->adap_free(adap);
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#ifdef CONFIG_MEDIA_CEC_RC
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rc_free_device(adap->rc);
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#endif
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kfree(adap);
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}
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EXPORT_SYMBOL_GPL(cec_delete_adapter);
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/*
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* Initialise cec for linux
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*/
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static int __init cec_devnode_init(void)
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{
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int ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES, CEC_NAME);
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if (ret < 0) {
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pr_warn("cec: unable to allocate major\n");
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return ret;
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}
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#ifdef CONFIG_DEBUG_FS
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top_cec_dir = debugfs_create_dir("cec", NULL);
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if (IS_ERR_OR_NULL(top_cec_dir)) {
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pr_warn("cec: Failed to create debugfs cec dir\n");
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top_cec_dir = NULL;
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}
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#endif
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ret = bus_register(&cec_bus_type);
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if (ret < 0) {
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unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
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pr_warn("cec: bus_register failed\n");
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return -EIO;
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}
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return 0;
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}
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static void __exit cec_devnode_exit(void)
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{
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debugfs_remove_recursive(top_cec_dir);
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bus_unregister(&cec_bus_type);
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unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
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}
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subsys_initcall(cec_devnode_init);
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module_exit(cec_devnode_exit)
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MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
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MODULE_DESCRIPTION("Device node registration for cec drivers");
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MODULE_LICENSE("GPL");
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