diff options
Diffstat (limited to 'drivers/media/cec/core/cec-core.c')
-rw-r--r-- | drivers/media/cec/core/cec-core.c | 465 |
1 files changed, 465 insertions, 0 deletions
diff --git a/drivers/media/cec/core/cec-core.c b/drivers/media/cec/core/cec-core.c new file mode 100644 index 000000000000..0c52e1bb3910 --- /dev/null +++ b/drivers/media/cec/core/cec-core.c @@ -0,0 +1,465 @@ +// 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 bool debug_phys_addr; +module_param(debug_phys_addr, bool, 0644); +MODULE_PARM_DESC(debug_phys_addr, "add CEC_CAP_PHYS_ADDR if set"); + +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; + kobject_set_name(&devnode->cdev.kobj, "cec%d", devnode->minor); + + devnode->registered = true; + ret = cdev_device_add(&devnode->cdev, &devnode->dev); + if (ret) { + devnode->registered = false; + pr_err("%s: cdev_device_add failed\n", __func__); + goto clr_bit; + } + + 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_DEBUG_FS +static ssize_t cec_error_inj_write(struct file *file, + const char __user *ubuf, size_t count, loff_t *ppos) +{ + struct seq_file *sf = file->private_data; + struct cec_adapter *adap = sf->private; + char *buf; + char *line; + char *p; + + buf = memdup_user_nul(ubuf, min_t(size_t, PAGE_SIZE, count)); + if (IS_ERR(buf)) + return PTR_ERR(buf); + p = buf; + while (p && *p) { + p = skip_spaces(p); + line = strsep(&p, "\n"); + if (!*line || *line == '#') + continue; + if (!adap->ops->error_inj_parse_line(adap, line)) { + kfree(buf); + return -EINVAL; + } + } + kfree(buf); + return count; +} + +static int cec_error_inj_show(struct seq_file *sf, void *unused) +{ + struct cec_adapter *adap = sf->private; + + return adap->ops->error_inj_show(adap, sf); +} + +static int cec_error_inj_open(struct inode *inode, struct file *file) +{ + return single_open(file, cec_error_inj_show, inode->i_private); +} + +static const struct file_operations cec_error_inj_fops = { + .open = cec_error_inj_open, + .write = cec_error_inj_write, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; +#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); + strscpy(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; + if (debug_phys_addr) + adap->capabilities |= CEC_CAP_PHYS_ADDR; + 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->input_phys, sizeof(adap->input_phys), + "%s/input0", adap->name); + + adap->rc->device_name = adap->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(550); +#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; + return 0; + } + if (!adap->ops->error_inj_show || !adap->ops->error_inj_parse_line) + return 0; + adap->error_inj_file = debugfs_create_file("error-inj", 0644, + adap->cec_dir, adap, + &cec_error_inj_fops); + if (IS_ERR_OR_NULL(adap->error_inj_file)) + pr_warn("cec-%s: Failed to create error-inj file\n", + adap->name); +#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 + cec_notifier_cec_adap_unregister(adap->notifier, adap); +#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"); |