path: root/drivers/thunderbolt/ctl.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt driver - control channel and configuration commands
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 * Copyright (C) 2018, Intel Corporation
 */

#include <linux/crc32.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/dmapool.h>
#include <linux/workqueue.h>

#include "ctl.h"


#define TB_CTL_RX_PKG_COUNT	10
#define TB_CTL_RETRIES		4

/**
 * struct tb_ctl - Thunderbolt control channel
 * @nhi: Pointer to the NHI structure
 * @tx: Transmit ring
 * @rx: Receive ring
 * @frame_pool: DMA pool for control messages
 * @rx_packets: Received control messages
 * @request_queue_lock: Lock protecting @request_queue
 * @request_queue: List of outstanding requests
 * @running: Is the control channel running at the moment
 * @timeout_msec: Default timeout for non-raw control messages
 * @callback: Callback called when hotplug message is received
 * @callback_data: Data passed to @callback
 */
struct tb_ctl {
	struct tb_nhi *nhi;
	struct tb_ring *tx;
	struct tb_ring *rx;

	struct dma_pool *frame_pool;
	struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
	struct mutex request_queue_lock;
	struct list_head request_queue;
	bool running;

	int timeout_msec;
	event_cb callback;
	void *callback_data;
};


#define tb_ctl_WARN(ctl, format, arg...) \
	dev_WARN(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_err(ctl, format, arg...) \
	dev_err(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_warn(ctl, format, arg...) \
	dev_warn(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_info(ctl, format, arg...) \
	dev_info(&(ctl)->nhi->pdev->dev, format, ## arg)

#define tb_ctl_dbg(ctl, format, arg...) \
	dev_dbg(&(ctl)->nhi->pdev->dev, format, ## arg)

static DECLARE_WAIT_QUEUE_HEAD(tb_cfg_request_cancel_queue);
/* Serializes access to request kref_get/put */
static DEFINE_MUTEX(tb_cfg_request_lock);

/**
 * tb_cfg_request_alloc() - Allocates a new config request
 *
 * This is refcounted object so when you are done with this, call
 * tb_cfg_request_put() to it.
 */
struct tb_cfg_request *tb_cfg_request_alloc(void)
{
	struct tb_cfg_request *req;

	req = kzalloc(sizeof(*req), GFP_KERNEL);
	if (!req)
		return NULL;

	kref_init(&req->kref);

	return req;
}

/**
 * tb_cfg_request_get() - Increase refcount of a request
 * @req: Request whose refcount is increased
 */
void tb_cfg_request_get(struct tb_cfg_request *req)
{
	mutex_lock(&tb_cfg_request_lock);
	kref_get(&req->kref);
	mutex_unlock(&tb_cfg_request_lock);
}

static void tb_cfg_request_destroy(struct kref *kref)
{
	struct tb_cfg_request *req = container_of(kref, typeof(*req), kref);

	kfree(req);
}

/**
 * tb_cfg_request_put() - Decrease refcount and possibly release the request
 * @req: Request whose refcount is decreased
 *
 * Call this function when you are done with the request. When refcount
 * goes to %0 the object is released.
 */
void tb_cfg_request_put(struct tb_cfg_request *req)
{
	mutex_lock(&tb_cfg_request_lock);
	kref_put(&req->kref, tb_cfg_request_destroy);
	mutex_unlock(&tb_cfg_request_lock);
}

static int tb_cfg_request_enqueue(struct tb_ctl *ctl,
				  struct tb_cfg_request *req)
{
	WARN_ON(test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags));
	WARN_ON(req->ctl);

	mutex_lock(&ctl->request_queue_lock);
	if (!ctl->running) {
		mutex_unlock(&ctl->request_queue_lock);
		return -ENOTCONN;
	}
	req->ctl = ctl;
	list_add_tail(&req->list, &ctl->request_queue);
	set_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
	mutex_unlock(&ctl->request_queue_lock);
	return 0;
}

static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
{
	struct tb_ctl *ctl = req->ctl;

	mutex_lock(&ctl->request_queue_lock);
	list_del(&req->list);
	clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
	if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
		wake_up(&tb_cfg_request_cancel_queue);
	mutex_unlock(&ctl->request_queue_lock);
}

static bool tb_cfg_request_is_active(struct tb_cfg_request *req)
{
	return test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
}

static struct tb_cfg_request *
tb_cfg_request_find(struct tb_ctl *ctl, struct ctl_pkg *pkg)
{
	struct tb_cfg_request *req = NULL, *iter;

	mutex_lock(&pkg->ctl->request_queue_lock);
	list_for_each_entry(iter, &pkg->ctl->request_queue, list) {
		tb_cfg_request_get(iter);
		if (iter->match(iter, pkg)) {
			req = iter;
			break;
		}
		tb_cfg_request_put(iter);
	}
	mutex_unlock(&pkg->ctl->request_queue_lock);

	return req;
}

/* utility functions */


static int check_header(