// SPDX-License-Identifier: GPL-2.0-only
/*
* cec-core.c - HDMI Consumer Electronics Control framework - Core
*
* Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
*/
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/types.h>
#include "cec-priv.h"
#define CEC_NUM_DEVICES 256
#define CEC_NAME "cec"
int cec_debug;
module_param_named(debug, cec_debug, int, 0644);
MODULE_PARM_DESC(debug, "debug level (0-2)");
static dev_t cec_dev_t;
/* Active devices */
static DEFINE_MUTEX(cec_devnode_lock);
static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES);
static struct dentry *top_cec_dir;
/* dev to cec_devnode */
#define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev)
int cec_get_device(struct cec_devnode *devnode)
{
/*
* Check if the cec device is available. This needs to be done with
* the devnode->lock held to prevent an open/unregister race:
* without the lock, the device could be unregistered and freed between
* the devnode->registered check and get_device() calls, leading to
* a crash.
*/
mutex_lock(&devnode->lock);
/*
* return ENXIO if the cec device has been removed
* already or if it is not registered anymore.
*/
if (!devnode->registered) {
mutex_unlock(&devnode->lock);
return -ENXIO;
}
/* and increase the device refcount */
get_device(&devnode->dev);
mutex_unlock(&devnode->lock);
return 0;
}
void cec_put_device(struct cec_devnode *devnode)
{
put_device(&devnode->dev);
}
/* Called when the last user of the cec device exits. */
static void cec_devnode_release(struct device *cd)
{
struct cec_devnode *devnode = to_cec_devnode(cd);
mutex_lock(&cec_devnode_lock);
/* Mark device node number as free */
clear_bit(devnode->minor, cec_devnode_nums);
mutex_unlock(&cec_devnode_lock);
cec_delete_adapter(to_cec_adapter(devnode));
}
static struct bus_type cec_bus_type = {
.name = CEC_NAME,
};
/*
* Register a cec device node
*
* The registration code assigns minor numbers and registers the new device node
* with the kernel. An error is returned if no free minor number can be found,
* or if the registration of the device node fails.
*
* Zero is returned on success.
*
* Note that if the cec_devnode_register call fails, the release() callback of
* the cec_devnode structure is *not* called, so the caller is responsible for
* freeing any data.
*/
static int __must_check cec_devnode_register(struct cec_devnode *devnode,
struct module *owner)
{
int minor;
int ret;
/* Part 1: Find a free minor number */
mutex_lock(&cec_devnode_lock);
minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0);
if (minor == CEC_NUM_DEVICES) {
mutex_unlock(&cec_devnode_lock);
pr_err("could not get a free minor\n");
return -ENFILE;
}
set_bit(minor, cec_devnode_nums);
mutex_unlock(&cec_devnode_lock);
devnode->minor = minor;
devnode->dev.bus = &cec_bus_type;
devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor);
devnode->dev.release = cec_devnode_release;
dev_set_name(&devnode->dev, "cec%d", devnode->minor);
device_initialize(&devnode->dev);
/* Part 2: Initialize and register the character device */
cdev_init(&devnode->cdev, &cec_devnode_fops);
devnode->cdev.owner = owner;
ret = cdev_device_add(&devnode->cdev, &devnode->dev);
if (ret) {
pr_err("%s: cdev_device_add failed\n", __func__);
goto clr_bit;
}
devnode->registered = true;
return 0;
clr_bit:
mutex_lock(&cec_devnode_lock);
clear_bit(devnode->minor, cec_devnode_nums);
mutex_unlock(&cec_devnode_lock);
return ret;
}
/*
* Unregister a cec device node
*
* This unregisters the passed device. Future open calls will be met with
* errors.
*
* This function can safely be called if the device node has never been
* registered or has already been unregistered.
*/
static void cec_devnode_unregister(struct cec_adapter *adap)
{
struct cec_devnode *devnode = &adap->devnode;
struct cec_fh *fh;
mutex_lock(&devnode->lock);
/* Check if devnode was never registered or already unregistered */
if (!devnode->registered || devnode->unregistered) {
mutex_unlock(&devnode->lock);
return;
}
list_for_each_entry(fh, &devnode->fhs, list)
wake_up_interruptible(&fh->wait);
devnode->registered = false;
devnode->unregistered = true;
mutex_unlock(&devnode->lock);
mutex_lock(&adap->lock);
__cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false);
__cec_s_log_addrs(adap, NULL, false);
mutex_unlock(&adap->lock);
cdev_device_del(&devnode->cdev, &devnode->dev);
put_device(&devnode->dev);
}
#ifdef CONFIG_CEC_NOTIFIER
static void cec_cec_notify(struct cec_adapter *adap, u16 pa)
{
cec_s_phys_addr(adap, pa, false);
}
void cec_register_cec_notifier(struct cec_adapter *adap,
struct cec_notifier *notifier)
{
if (WARN_ON(!cec_is_registered(adap)))
return;
adap->notifier = notifier;
cec_notifier_register(adap->notifier, adap, cec_cec_notify);
}
EXPORT_SYMBOL_GPL(cec_register_cec_notifier);
#endif
struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
void *priv, const char *name, u32 caps,
u8 available_las)
{
struct cec_adapter *adap;
int res;
#ifndef CONFIG_MEDIA_CEC_RC
caps &= ~CEC_CAP_RC;
#endif
if (WARN_ON(!caps))
return ERR_PTR(-EINVAL);
if (WARN_ON(!ops))
return ERR_PTR(-EINVAL);
if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS))
return ERR_PTR(-EINVAL);
adap = kzalloc(sizeof(*adap), GFP_KERNEL);
if (!adap)
return ERR_PTR(-ENOMEM);
strlcpy(adap->name, name, sizeof(adap->name));
adap->phys_addr = CEC_PHYS_ADDR_INVALID;
adap->cec_pin_is_high = true;
adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0;
adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE;
adap->capabilities = caps;
adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD;
adap->available_log_addrs = available_las;
adap->sequence = 0;
adap->ops = ops;
adap->priv = priv;
memset(adap->phys_addrs, 0xff, sizeof(adap->phys_addrs));
mutex_init(&adap->lock);
INIT_LIST_HEAD(&adap->transmit_queue);
INIT_LIST_HEAD(&adap->wait_queue);
init_waitqueue_head(&adap->kthread_waitq);
/* adap->devnode initialization */
INIT_LIST_HEAD(&adap->devnode.fhs);
mutex_init(&adap->devnode.lock);
adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name);
if (IS_ERR(adap->kthread)) {
pr_err("cec-%s: kernel_thread() failed\n", name);
res = PTR_ERR(adap->kthread);
kfree(adap);
return ERR_PTR(res);
}
#ifdef CONFIG_MEDIA_CEC_RC
if (!(caps & CEC_CAP_RC))
return adap;
/* Prepare the RC input device */
adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE);
if (!adap->rc) {
pr_err("cec-%s: failed to allocate memory for rc_dev\n",
name);
kthread_stop(adap->kthread);
kfree(adap);
return ERR_PTR(-ENOMEM);
}
snprintf(adap->device_name, sizeof(adap->device_name),
"RC for %s", name);
snprintf(adap->input_phys, sizeof(adap->input_phys),
"%s/input0", name);
adap->rc->device_name = adap->device_name;
adap->rc->input_phys = adap->input_phys;
adap->rc->input_id.bustype = BUS_CEC;
adap->rc->input_id.vendor = 0;
adap->rc->input_id.product = 0;
adap->rc->input_id.version = 1;
adap->rc->driver_name = CEC_NAME;
adap->rc->allowed_protocols = RC_PROTO_BIT_CEC;
adap->rc->priv = adap;
adap->rc->map_name = RC_MAP_CEC;
adap->rc->timeout = MS_TO_NS(100);
#endif
return adap;
}
EXPORT_SYMBOL_GPL(cec_allocate_adapter);
int cec_register_adapter(struct cec_adapter *adap,
struct device *parent)
{
int res;
if (IS_ERR_OR_NULL(adap))
return 0;
if (WARN_ON(!parent))
return -EINVAL;
adap->owner = parent->driver->owner;
adap->devnode.dev.parent = parent;
#ifdef CONFIG_MEDIA_CEC_RC
if (adap->capabilities & CEC_CAP_RC) {
adap->rc->dev.parent = parent;
res = rc_register_device(adap->rc);
if (res) {
pr_err("cec-%s: failed to prepare input device\n",
adap->name);
rc_free_device(adap->rc);
adap->rc = NULL;
return res;
}
}
#endif
res = cec_devnode_register(&adap->devnode, adap->owner);
if (res) {
#ifdef CONFIG_MEDIA_CEC_RC
/* Note: rc_unregister also calls rc_free */
rc_unregister_device(adap->rc);
adap->rc = NULL;
#endif
return res;
}
dev_set_drvdata(&adap->devnode.dev, adap);
#ifdef CONFIG_DEBUG_FS
if (!top_cec_dir)
return 0;
adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), top_cec_dir);
if (IS_ERR_OR_NULL(adap->cec_dir)) {
pr_warn("cec-%s: Failed to create debugfs dir\n", adap->name);
return 0;
}
adap->status_file = debugfs_create_devm_seqfile(&adap->devnode.dev,
"status", adap->cec_dir, cec_adap_status);
if (IS_ERR_OR_NULL(adap->status_file)) {
pr_warn("cec-%s: Failed to create status file\n", adap->name);
debugfs_remove_recursive(adap->cec_dir);
adap->cec_dir = NULL;
}
#endif
return 0;
}
EXPORT_SYMBOL_GPL(cec_register_adapter);
void cec_unregister_adapter(struct cec_adapter *adap)
{
if (IS_ERR_OR_NULL(adap))
return;
#ifdef CONFIG_MEDIA_CEC_RC
/* Note: rc_unregister also calls rc_free */
rc_unregister_device(adap->rc);
adap->rc = NULL;
#endif
debugfs_remove_recursive(adap->cec_dir);
#ifdef CONFIG_CEC_NOTIFIER
if (adap->notifier)
cec_notifier_unregister(adap->notifier);
#endif
cec_devnode_unregister(adap);
}
EXPORT_SYMBOL_GPL(cec_unregister_adapter);
void cec_delete_adapter(struct cec_adapter *adap)
{
if (IS_ERR_OR_NULL(adap))
return;
kthread_stop(adap->kthread);
if (adap->kthread_config)
kthread_stop(adap->kthread_config);
if (adap->ops->adap_free)
adap->ops->adap_free(adap);
#ifdef CONFIG_MEDIA_CEC_RC
rc_free_device(adap->rc);
#endif
kfree(adap);
}
EXPORT_SYMBOL_GPL(cec_delete_adapter);
/*
* Initialise cec for linux
*/
static int __init cec_devnode_init(void)
{
int ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES, CEC_NAME);
if (ret < 0) {
pr_warn("cec: unable to allocate major\n");
return ret;
}
#ifdef CONFIG_DEBUG_FS
top_cec_dir = debugfs_create_dir("cec", NULL);
if (IS_ERR_OR_NULL(top_cec_dir)) {
pr_warn("cec: Failed to create debugfs cec dir\n");
top_cec_dir = NULL;
}
#endif
ret = bus_register(&cec_bus_type);
if (ret < 0) {
unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
pr_warn("cec: bus_register failed\n");
return -EIO;
}
return 0;
}
static void __exit cec_devnode_exit(void)
{
debugfs_remove_recursive(top_cec_dir);
bus_unregister(&cec_bus_type);
unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES);
}
subsys_initcall(cec_devnode_init);
module_exit(cec_devnode_exit)
MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>");
MODULE_DESCRIPTION("Device node registration for cec drivers");
MODULE_LICENSE("GPL");