path: root/drivers/hwtracing/intel_th/core.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Intel(R) Trace Hub driver core
 *
 * Copyright (C) 2014-2015 Intel Corporation.
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/sysfs.h>
#include <linux/kdev_t.h>
#include <linux/debugfs.h>
#include <linux/idr.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>
#include <linux/dma-mapping.h>

#include "intel_th.h"
#include "debug.h"

static bool host_mode __read_mostly;
module_param(host_mode, bool, 0444);

static DEFINE_IDA(intel_th_ida);

static int intel_th_match(struct device *dev, struct device_driver *driver)
{
	struct intel_th_driver *thdrv = to_intel_th_driver(driver);
	struct intel_th_device *thdev = to_intel_th_device(dev);

	if (thdev->type == INTEL_TH_SWITCH &&
	    (!thdrv->enable || !thdrv->disable))
		return 0;

	return !strcmp(thdev->name, driver->name);
}

static int intel_th_child_remove(struct device *dev, void *data)
{
	device_release_driver(dev);

	return 0;
}

static int intel_th_probe(struct device *dev)
{
	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
	struct intel_th_device *thdev = to_intel_th_device(dev);
	struct intel_th_driver *hubdrv;
	struct intel_th_device *hub = NULL;
	int ret;

	if (thdev->type == INTEL_TH_SWITCH)
		hub = thdev;
	else if (dev->parent)
		hub = to_intel_th_device(dev->parent);

	if (!hub || !hub->dev.driver)
		return -EPROBE_DEFER;

	hubdrv = to_intel_th_driver(hub->dev.driver);

	pm_runtime_set_active(dev);
	pm_runtime_no_callbacks(dev);
	pm_runtime_enable(dev);

	ret = thdrv->probe(to_intel_th_device(dev));
	if (ret)
		goto out_pm;

	if (thdrv->attr_group) {
		ret = sysfs_create_group(&thdev->dev.kobj, thdrv->attr_group);
		if (ret)
			goto out;
	}

	if (thdev->type == INTEL_TH_OUTPUT &&
	    !intel_th_output_assigned(thdev))
		/* does not talk to hardware */
		ret = hubdrv->assign(hub, thdev);

out:
	if (ret)
		thdrv->remove(thdev);

out_pm:
	if (ret)
		pm_runtime_disable(dev);

	return ret;
}

static void intel_th_device_remove(struct intel_th_device *thdev);

static void intel_th_remove(struct device *dev)
{
	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
	struct intel_th_device *thdev = to_intel_th_device(dev);
	struct intel_th_device *hub = to_intel_th_hub(thdev);

	if (thdev->type == INTEL_TH_SWITCH) {
		struct intel_th *th = to_intel_th(hub);
		int i, lowest;

		/*
		 * disconnect outputs
		 *
		 * intel_th_child_remove returns 0 unconditionally, so there is
		 * no need to check the return value of device_for_each_child.
		 */
		device_for_each_child(dev, thdev, intel_th_child_remove);

		/*
		 * Remove outputs, that is, hub's children: they are created
		 * at hub's probe time by having the hub call
		 * intel_th_output_enable() for each of them.
		 */
		for (i = 0, lowest = -1; i < th->num_thdevs; i++) {
			/*
			 * Move the non-output devices from higher up the
			 * th->thdev[] array to lower positions to maintain
			 * a contiguous array.
			 */
			if (th->thdev[i]->type != INTEL_TH_OUTPUT) {
				if (lowest >= 0) {
					th->thdev[lowest] = th->thdev[i];
					th->thdev[i] = NULL;
					++lowest;
				}

				continue;
			}

			if (lowest == -1)
				lowest = i;

			intel_th_device_remove(th->thdev[i]);
			th->thdev[i] = NULL;
		}

		if (lowest >= 0)
			th->num_thdevs = lowest;
	}

	if (thdrv->attr_group)
		sysfs_remove_group(&thdev->dev.kobj, thdrv->attr_group);

	pm_runtime_get_sync(dev);

	thdrv->remove(thdev);

	if (intel_th_output_assigned(thdev)) {
		struct intel_th_driver *hubdrv =
			to_intel_th_driver(dev->parent->driver);

		if (hub->dev.driver)
			/* does not talk to hardware */
			hubdrv->unassign(hub, thdev);
	}

	pm_runtime_disable(dev);
	pm_runtime_set_active(dev);
	pm_runtime_enable(dev);
}

static struct bus_type intel_th_bus = {
	.name		= "intel_th",
	.