path: root/drivers/thunderbolt/nhi.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Thunderbolt driver - NHI driver
 *
 * The NHI (native host interface) is the pci device that allows us to send and
 * receive frames from the thunderbolt bus.
 *
 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
 * Copyright (C) 2018, Intel Corporation
 */

#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/property.h>
#include <linux/string_helpers.h>

#include "nhi.h"
#include "nhi_regs.h"
#include "tb.h"

#define RING_TYPE(ring) ((ring)->is_tx ? "TX ring" : "RX ring")

#define RING_FIRST_USABLE_HOPID	1
/*
 * Used with QUIRK_E2E to specify an unused HopID the Rx credits are
 * transferred.
 */
#define RING_E2E_RESERVED_HOPID	RING_FIRST_USABLE_HOPID
/*
 * Minimal number of vectors when we use MSI-X. Two for control channel
 * Rx/Tx and the rest four are for cross domain DMA paths.
 */
#define MSIX_MIN_VECS		6
#define MSIX_MAX_VECS		16

#define NHI_MAILBOX_TIMEOUT	500 /* ms */

/* Host interface quirks */
#define QUIRK_AUTO_CLEAR_INT	BIT(0)
#define QUIRK_E2E		BIT(1)

static int ring_interrupt_index(const struct tb_ring *ring)
{
	int bit = ring->hop;
	if (!ring->is_tx)
		bit += ring->nhi