// SPDX-License-Identifier: GPL-2.0-only
/*
 * cec-notifier.c - notify CEC drivers of physical address changes
 *
 * Copyright 2016 Russell King.
 * Copyright 2016-2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
 */

#include <linux/export.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/kref.h>
#include <linux/of_platform.h>

#include <media/cec.h>
#include <media/cec-notifier.h>
#include <drm/drm_edid.h>

struct cec_notifier {
        struct mutex lock;
        struct list_head head;
        struct kref kref;
        struct device *hdmi_dev;
        struct cec_connector_info conn_info;
        const char *port_name;
        struct cec_adapter *cec_adap;

        u16 phys_addr;
};

static LIST_HEAD(cec_notifiers);
static DEFINE_MUTEX(cec_notifiers_lock);

/**
 * cec_notifier_get_conn - find or create a new cec_notifier for the given
 * device and connector tuple.
 * @hdmi_dev: device that sends the events.
 * @port_name: the connector name from which the event occurs
 *
 * If a notifier for device @dev already exists, then increase the refcount
 * and return that notifier.
 *
 * If it doesn't exist, then allocate a new notifier struct and return a
 * pointer to that new struct.
 *
 * Return NULL if the memory could not be allocated.
 */
static struct cec_notifier *
cec_notifier_get_conn(struct device *hdmi_dev, const char *port_name)
{
        struct cec_notifier *n;

        mutex_lock(&cec_notifiers_lock);
        list_for_each_entry(n, &cec_notifiers, head) {
                if (n->hdmi_dev == hdmi_dev &&
                    (!port_name ||
                     (n->port_name && !strcmp(n->port_name, port_name)))) {
                        kref_get(&n->kref);
                        mutex_unlock(&cec_notifiers_lock);
                        return n;
                }
        }
        n = kzalloc_obj(*n);
        if (!n)
                goto unlock;
        n->hdmi_dev = hdmi_dev;
        if (port_name) {
                n->port_name = kstrdup(port_name, GFP_KERNEL);
                if (!n->port_name) {
                        kfree(n);
                        n = NULL;
                        goto unlock;
                }
        }
        n->phys_addr = CEC_PHYS_ADDR_INVALID;

        mutex_init(&n->lock);
        kref_init(&n->kref);
        list_add_tail(&n->head, &cec_notifiers);
unlock:
        mutex_unlock(&cec_notifiers_lock);
        return n;
}

static void cec_notifier_release(struct kref *kref)
{
        struct cec_notifier *n =
                container_of(kref, struct cec_notifier, kref);

        list_del(&n->head);
        kfree(n->port_name);
        kfree(n);
}

static void cec_notifier_put(struct cec_notifier *n)
{
        mutex_lock(&cec_notifiers_lock);
        kref_put(&n->kref, cec_notifier_release);
        mutex_unlock(&cec_notifiers_lock);
}

struct cec_notifier *
cec_notifier_conn_register(struct device *hdmi_dev, const char *port_name,
                           const struct cec_connector_info *conn_info)
{
        struct cec_notifier *n = cec_notifier_get_conn(hdmi_dev, port_name);

        if (!n)
                return n;

        mutex_lock(&n->lock);
        n->phys_addr = CEC_PHYS_ADDR_INVALID;
        if (conn_info)
                n->conn_info = *conn_info;
        else
                memset(&n->conn_info, 0, sizeof(n->conn_info));
        if (n->cec_adap) {
                if (!n->cec_adap->adap_controls_phys_addr)
                        cec_phys_addr_invalidate(n->cec_adap);
                cec_s_conn_info(n->cec_adap, conn_info);
        }
        mutex_unlock(&n->lock);
        return n;
}
EXPORT_SYMBOL_GPL(cec_notifier_conn_register);

void cec_notifier_conn_unregister(struct cec_notifier *n)
{
        if (!n)
                return;

        mutex_lock(&n->lock);
        memset(&n->conn_info, 0, sizeof(n->conn_info));
        n->phys_addr = CEC_PHYS_ADDR_INVALID;
        if (n->cec_adap) {
                if (!n->cec_adap->adap_controls_phys_addr)
                        cec_phys_addr_invalidate(n->cec_adap);
                cec_s_conn_info(n->cec_adap, NULL);
        }
        mutex_unlock(&n->lock);
        cec_notifier_put(n);
}
EXPORT_SYMBOL_GPL(cec_notifier_conn_unregister);

struct cec_notifier *
cec_notifier_cec_adap_register(struct device *hdmi_dev, const char *port_name,
                               struct cec_adapter *adap)
{
        struct cec_notifier *n;

        if (WARN_ON(!adap))
                return NULL;

        n = cec_notifier_get_conn(hdmi_dev, port_name);
        if (!n)
                return n;

        mutex_lock(&n->lock);
        n->cec_adap = adap;
        adap->conn_info = n->conn_info;
        adap->notifier = n;
        if (!adap->adap_controls_phys_addr)
                cec_s_phys_addr(adap, n->phys_addr, false);
        mutex_unlock(&n->lock);
        return n;
}
EXPORT_SYMBOL_GPL(cec_notifier_cec_adap_register);

void cec_notifier_cec_adap_unregister(struct cec_notifier *n,
                                      struct cec_adapter *adap)
{
        if (!n)
                return;

        mutex_lock(&n->lock);
        adap->notifier = NULL;
        n->cec_adap = NULL;
        mutex_unlock(&n->lock);
        cec_notifier_put(n);
}
EXPORT_SYMBOL_GPL(cec_notifier_cec_adap_unregister);

void cec_notifier_set_phys_addr(struct cec_notifier *n, u16 pa)
{
        if (n == NULL)
                return;

        mutex_lock(&n->lock);
        n->phys_addr = pa;
        if (n->cec_adap && !n->cec_adap->adap_controls_phys_addr)
                cec_s_phys_addr(n->cec_adap, n->phys_addr, false);
        mutex_unlock(&n->lock);
}
EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr);

/*
 * Note: In the drm subsystem, prefer calling (if possible):
 *
 * cec_notifier_set_phys_addr(n, connector->display_info.source_physical_address);
 */
void cec_notifier_set_phys_addr_from_edid(struct cec_notifier *n,
                                          const struct edid *edid)
{
        u16 pa = CEC_PHYS_ADDR_INVALID;

        if (n == NULL)
                return;

        if (edid && edid->extensions)
                pa = cec_get_edid_phys_addr((const u8 *)edid,
                                EDID_LENGTH * (edid->extensions + 1), NULL);
        cec_notifier_set_phys_addr(n, pa);
}
EXPORT_SYMBOL_GPL(cec_notifier_set_phys_addr_from_edid);

struct device *cec_notifier_parse_hdmi_phandle(struct device *dev)
{
        struct platform_device *hdmi_pdev;
        struct device *hdmi_dev = NULL;
        struct device_node *np;

        np = of_parse_phandle(dev->of_node, "hdmi-phandle", 0);

        if (!np) {
                dev_err(dev, "Failed to find HDMI node in device tree\n");
                return ERR_PTR(-ENODEV);
        }

        hdmi_pdev = of_find_device_by_node(np);
        if (hdmi_pdev)
                hdmi_dev = &hdmi_pdev->dev;
#if IS_REACHABLE(CONFIG_I2C)
        if (!hdmi_dev) {
                struct i2c_client *hdmi_client = of_find_i2c_device_by_node(np);

                if (hdmi_client)
                        hdmi_dev = &hdmi_client->dev;
        }
#endif
        of_node_put(np);
        if (!hdmi_dev)
                return ERR_PTR(-EPROBE_DEFER);

        /*
         * Note that the device struct is only used as a key into the
         * cec_notifiers list, it is never actually accessed.
         * So we decrement the reference here so we don't leak
         * memory.
         */
        put_device(hdmi_dev);
        return hdmi_dev;
}
EXPORT_SYMBOL_GPL(cec_notifier_parse_hdmi_phandle);