path: root/drivers/thunderbolt/xdomain.c

/*
 * Thunderbolt XDomain discovery protocol support
 *
 * Copyright (C) 2017, Intel Corporation
 * Authors: Michael Jamet <michael.jamet@intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/utsname.h>
#include <linux/uuid.h>
#include <linux/workqueue.h>

#include "tb.h"

#define XDOMAIN_DEFAULT_TIMEOUT			5000 /* ms */
#define XDOMAIN_PROPERTIES_RETRIES		60
#define XDOMAIN_PROPERTIES_CHANGED_RETRIES	10

struct xdomain_request_work {
	struct work_struct work;
	struct tb_xdp_header *pkg;
	struct tb *tb;
};

/* Serializes access to the properties and protocol handlers below */
static DEFINE_MUTEX(xdomain_lock);

/* Properties exposed to the remote domains */
static struct tb_property_dir *xdomain_property_dir;
static u32 *xdomain_property_block;
static u32 xdomain_property_block_len;
static u32 xdomain_property_block_gen;

/* Additional protocol handlers */
static LIST_HEAD(protocol_handlers);

/* UUID for XDomain discovery protocol: b638d70e-42ff-40bb-97c2-90e2c0b2ff07 */
static const uuid_t tb_xdp_uuid =
	UUID_INIT(0xb638d70e, 0x42ff, 0x40bb,
		  0x97, 0xc2, 0x90, 0xe2, 0xc0, 0xb2, 0xff, 0x07);

static bool tb_xdomain_match(const struct tb_cfg_request *req,
			     const struct ctl_pkg *pkg)
{
	switch (pkg->frame.eof) {
	case TB_CFG_PKG_ERROR:
		return true;

	case TB_CFG_PKG_XDOMAIN_RESP: {
		const struct tb_xdp_header *res_hdr = pkg->buffer;
		const struct tb_xdp_header *req_hdr = req->request;

		if (pkg->frame.size < req->response_size / 4)
			return false;

		/* Make sure route matches */
		if ((res_hdr->xd_hdr.route_hi & ~BIT(31)) !=
		     req_hdr->xd_hdr.route_hi)
			return false;
		if ((res_hdr->xd_hdr.route_lo) != req_hdr->xd_hdr.route_lo)
			return false;

		/* Check that the XDomain protocol matches */
		if (!uuid_equal(&res_hdr->uuid, &req_hdr->uuid))
			return false;

		return true;
	}

	default:
		return false;
	}
}

static bool tb_xdomain_copy(struct tb_cfg_request *req,
			    const struct ctl_pkg *pkg)
{
	memcpy(req->response, pkg->buffer, req->response_size);
	req->result.err = 0;
	return true;
}

static void response_ready(void *data)
{
	tb_cfg_request_put(data);
}

static int __tb_xdomain_response(struct tb_ctl *ctl, const void *response,
				 size_t size, enum tb_cfg_pkg_type type)
{
	struct tb_cfg_request *req;

	req = tb_cfg_request_alloc();
	if (!req)
		return -ENOMEM;

	req->match = tb_xdomain_match;
	req->copy = tb_xdomain_copy;
	req->request = response;
	req->request_size = size;
	req->request_type = type;

	return tb_cfg_request(ctl, req, response_ready, req);
}

/**
 * tb_xdomain_response() - Send a XDomain response message
 * @xd: XDomain to send the message
 * @response: Response to send
 * @size: Size of the response
 * @type: PDF type of the response
 *
 * This can be used to send a XDomain response message to the other
 * domain. No response for the message is expected.
 *
 * Return: %0 in case of success and negative errno in case of failure
 */
int tb_xdomain_response(struct tb_xdomain *xd, const void *response,
			size_t size, enum tb_cfg_pkg_type type)
{
	return __tb_xdomain_response(xd->tb->ctl, response, size, type);
}
EXPORT_SYMBOL_GPL(tb_xdomain_response);

static int __tb_xdomain_request(struct tb_ctl *ctl, const void *request,
	size_t request_size, enum tb_cfg_pkg_type request_type, void *response,
	size_t response_size, enum tb_cfg_pkg_type response_type,
	unsigned int timeout_msec)
{
	struct tb_cfg_request *req;
	struct tb_cfg_result res;

	req = tb_cfg_request_alloc();
	if (!req)
		return -ENOMEM;

	req->match = tb_xdomain_match;
	req->copy = tb_xdomain_copy;
	req->request = request;
	req->request_size = request_size;
	req->request_type = request_type;
	req->response = response;
	req->response_size = response_size;
	req->response_type = response_type;

	res = tb_cfg_request_sync(ctl, req, timeout_msec);

	tb_cfg_request_put(req);

	return res.err == 1 ? -EIO : res.err;
}

/**
 * tb_xdomain_request() - Send a XDomain request
 * @xd: XDomain to send the request
 * @request: Request to send
 * @request_size: Size of the request in bytes
 * @re