path: root/drivers/gpu/host1x/bus.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Avionic Design GmbH
 * Copyright (C) 2012-2013, NVIDIA Corporation
 */

#include <linux/debugfs.h>
#include <linux/dma-mapping.h>
#include <linux/host1x.h>
#include <linux/of.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/of_device.h>

#include "bus.h"
#include "dev.h"

static DEFINE_MUTEX(clients_lock);
static LIST_HEAD(clients);

static DEFINE_MUTEX(drivers_lock);
static LIST_HEAD(drivers);

static DEFINE_MUTEX(devices_lock);
static LIST_HEAD(devices);

struct host1x_subdev {
	struct host1x_client *client;
	struct device_node *np;
	struct list_head list;
};

/**
 * host1x_subdev_add() - add a new subdevice with an associated device node
 * @device: host1x device to add the subdevice to
 * @driver: host1x driver containing the subdevices
 * @np: device node
 */
static int host1x_subdev_add(struct host1x_device *device,
			     struct host1x_driver *driver,
			     struct device_node *np)
{
	struct host1x_subdev *subdev;
	int err;

	subdev = kzalloc(sizeof(*subdev), GFP_KERNEL);
	if (!subdev)
		return -ENOMEM;

	INIT_LIST_HEAD(&subdev->list);
	subdev->np = of_node_get(np);

	mutex_lock(&device->subdevs_lock);
	list_add_tail(&subdev->list, &device->subdevs);
	mutex_unlock(&device->subdevs_lock);

	/* recursively add children */
	for_each_child_of_node_scoped(np, child) {
		if (of_match_node(driver->subdevs, child) &&
		    of_device_is_available(child)) {
			err = host1x_subdev_add(device, driver, child);
			if (err < 0) {
				/* XXX cleanup? */
				return err;
			}
		}
	}

	return 0;
}

/**
 * host1x_subdev_del() - remove subdevice
 * @subdev: subdevice to remove
 */
static void host1x_subdev_del(struct host1x_subdev *subdev)
{
	list_del(&subdev->list);
	of_node_put(subdev->np);
	kfree(subdev);
}

/**
 * host1x_device_parse_dt() - scan device tree and add matching subdevices
 * @device: host1x logical device
 * @driver: host1x driver
 */
static int host1x_device_parse_dt(struct host1x_device *device,
				  struct host1x_driver *driver)
{
	int err;

	for_each_child_of_node_scoped(device->dev.parent->of_node, np) {
		if (of_match_node(driver->subdevs, np) &&
		    of_device_is_available(np)) {
			err = host1x_subdev_add(device, driver, np);
			if (err < 0)
				return err;
		}
	}

	return 0;
}

static void host1x_subdev_register(struct host1x_device *device,
				   struct host1x_subdev *subdev,
				   struct host1x_client *client)
{
	int err;

	/*
	 * Move the subdevice to the list of active (registered) subdevices
	 * and associate it with a client. At the same time, associate the
	 * client with its parent device.
	 */
	mutex_lock(&device->subdevs_lock);
	mutex_lock(&device->clients_lock);
	list_move_tail(&client->list, &device->clients);
	list_move_tail(&subdev->list, &device->active);
	client->host = &device->dev;
	subdev->client = client;
	mutex_unlock(&device->clients_lock);
	mutex_unlock(&device->subdevs_lock);

	if (list_empty(&device->subdevs)) {
		err = device_add(&device->dev);
		if (err < 0)
			dev_err(&device->dev, "failed to add: %d\n", err);
		else
			device->registered = true;
	}
}

static void __host1x_subdev_unregister(struct host1x_device *device,
				       struct host1x_subdev *subdev)
{
	struct host1x_client *client = subdev->client;

	/*
	 * If all subdevices have been activated, we're about to remove the
	 * first active subdevice, so unload the driver first.
	 */
	if (list_empty(&device->subdevs)) {
		if (device->registered) {
			device->registered = false;
			device_del(&device->dev);
		}
	}

	/*
	 * Move the subdevice back to the list of idle subdevices and remove
	 * it from list of clients.
	 */
	mutex_lock(&device->clients_lock);
	subdev->client = NULL;
	client->host = NULL;
	list_move_tail(&subdev->list, &device->subdevs);
	/*
	 * XXX: Perhaps don't do this here, but rather explicitly remove it
	 * when the device is about to be deleted.
	 *
	 * This is somewhat complicated by the fact that this function is
	 * used to remove the subdevice when a client is unregistered but
	 * also when the composite device is about to be removed.
	 */
	list_del_init(&client->list);
	mutex_unlock(&device->clients_lock);
}

static void host1x_subdev_unregister(struct host1x_device *device,
				     struct host1x_subdev *subdev)
{
	mutex_lock(