Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1220 insertions, 0 deletions

diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
new file mode 100644
index 000000000..384623c49
--- /dev/null
+++ b/drivers/thunderbolt/nhi.c
@@ -0,0 +1,1220 @@
+/*
+ * Thunderbolt Cactus Ridge 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>
+ */
+
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+
+#include "nhi.h"
+#include "nhi_regs.h"
+#include "tb.h"
+
+#define RING_TYPE(ring) ((ring)->is_tx ? "TX ring" : "RX ring")
+
+/*
+ * Used to enable end-to-end workaround for missing RX packets. Do not
+ * use this ring for anything else.
+ */
+#define RING_E2E_UNUSED_HOPID	2
+/* HopIDs 0-7 are reserved by the Thunderbolt protocol */
+#define RING_FIRST_USABLE_HOPID	8
+
+/*
+ * 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 */
+
+static int ring_interrupt_index(struct tb_ring *ring)
+{
+	int bit = ring->hop;
+	if (!ring->is_tx)
+		bit += ring->nhi->hop_count;
+	return bit;
+}
+
+/**
+ * ring_interrupt_active() - activate/deactivate interrupts for a single ring
+ *
+ * ring->nhi->lock must be held.
+ */
+static void ring_interrupt_active(struct tb_ring *ring, bool active)
+{
+	int reg = REG_RING_INTERRUPT_BASE +
+		  ring_interrupt_index(ring) / 32 * 4;
+	int bit = ring_interrupt_index(ring) & 31;
+	int mask = 1 << bit;
+	u32 old, new;
+
+	if (ring->irq > 0) {
+		u32 step, shift, ivr, misc;
+		void __iomem *ivr_base;
+		int index;
+
+		if (ring->is_tx)
+			index = ring->hop;
+		else
+			index = ring->hop + ring->nhi->hop_count;
+
+		/*
+		 * Ask the hardware to clear interrupt status bits automatically
+		 * since we already know which interrupt was triggered.
+		 */
+		misc = ioread32(ring->nhi->iobase + REG_DMA_MISC);
+		if (!(misc & REG_DMA_MISC_INT_AUTO_CLEAR)) {
+			misc |= REG_DMA_MISC_INT_AUTO_CLEAR;
+			iowrite32(misc, ring->nhi->iobase + REG_DMA_MISC);
+		}
+
+		ivr_base = ring->nhi->iobase + REG_INT_VEC_ALLOC_BASE;
+		step = index / REG_INT_VEC_ALLOC_REGS * REG_INT_VEC_ALLOC_BITS;
+		shift = index % REG_INT_VEC_ALLOC_REGS * REG_INT_VEC_ALLOC_BITS;
+		ivr = ioread32(ivr_base + step);
+		ivr &= ~(REG_INT_VEC_ALLOC_MASK << shift);
+		if (active)
+			ivr |= ring->vector << shift;
+		iowrite32(ivr, ivr_base + step);
+	}
+
+	old = ioread32(ring->nhi->iobase + reg);
+	if (active)
+		new = old | mask;
+	else
+		new = old & ~mask;
+
+	dev_info(&ring->nhi->pdev->dev,
+		 "%s interrupt at register %#x bit %d (%#x -> %#x)\n",
+		 active ? "enabling" : "disabling", reg, bit, old, new);
+
+	if (new == old)
+		dev_WARN(&ring->nhi->pdev->dev,
+					 "interrupt for %s %d is already %s\n",
+					 RING_TYPE(ring), ring->hop,
+					 active ? "enabled" : "disabled");
+	iowrite32(new, ring->nhi->iobase + reg);
+}
+
+/**
+ * nhi_disable_interrupts() - disable interrupts for all rings
+ *
+ * Use only during init and shutdown.
+ */
+static void nhi_disable_interrupts(struct tb_nhi *nhi)
+{
+	int i = 0;
+	/* disable interrupts */
+	for (i = 0; i < RING_INTERRUPT_REG_COUNT(nhi); i++)
+		iowrite32(0, nhi->iobase + REG_RING_INTERRUPT_BASE + 4 * i);
+
+	/* clear interrupt status bits */
+	for (i = 0; i < RING_NOTIFY_REG_COUNT(nhi); i++)
+		ioread32(nhi->iobase + REG_RING_NOTIFY_BASE + 4 * i);
+}
+
+/* ring helper methods */
+
+static void __iomem *ring_desc_base(struct tb_ring *ring)
+{
+	void __iomem *io = ring->nhi->iobase;
+	io += ring->is_tx ? REG_TX_RING_BASE : REG_RX_RING_BASE;
+	io += ring->hop * 16;
+	return io;
+}
+
+static void __iomem *ring_options_base(struct tb_ring *ring)
+{
+	void __iomem *io = ring->nhi->iobase;
+	io += ring->is_tx ? REG_TX_OPTIONS_BASE : REG_RX_OPTIONS_BASE;
+	io += ring->hop * 32;
+	return io;
+}
+
+static void ring_iowrite_cons(struct tb_ring *ring, u16 cons)
+{
+	/*
+	 * The other 16-bits in the register is read-only and writes to it
+	 * are ignored by the hardware so we can save one ioread32() by
+	 * filling the read-only bits with zeroes.
+	 */
+	iowrite32(cons, ring_desc_base(ring) + 8);
+}
+
+static void ring_iowrite_prod(struct tb_ring *ring, u16 prod)
+{
+	/* See ring_iowrite_cons() above for explanation */
+	iowrite32(prod << 16, ring_desc_base(ring) + 8);
+}
+
+static void ring_iowrite32desc(struct tb_ring *ring, u32 value, u32 offset)
+{
+	iowrite32(value, ring_desc_base(ring) + offset);
+}
+
+static void ring_iowrite64desc(struct tb_ring *ring, u64 value, u32 offset)
+{
+	iowrite32(value, ring_desc_base(ring) + offset);
+	iowrite32(value >> 32, ring_desc_base(ring) + offset + 4);
+}
+
+static void ring_iowrite32options(struct tb_ring *ring, u32 value, u32 offset)
+{
+	iowrite32(value, ring_options_base(ring) + offset);
+}
+
+static bool ring_full(struct tb_ring *ring)
+{
+	return ((ring->head + 1) % ring->size) == ring->tail;
+}
+
+static bool ring_empty(struct tb_ring *ring)
+{
+	return ring->head == ring->tail;
+}
+
+/**
+ * ring_write_descriptors() - post frames from ring->queue to the controller
+ *
+ * ring->lock is held.
+ */
+static void ring_write_descriptors(struct tb_ring *ring)
+{
+	struct ring_frame *frame, *n;
+	struct ring_desc *descriptor;
+	list_for_each_entry_safe(frame, n, &ring->queue, list) {
+		if (ring_full(ring))
+			break;
+		list_move_tail(&frame->list, &ring->in_flight);
+		descriptor = &ring->descriptors[ring->head];
+		descriptor->phys = frame->buffer_phy;
+		descriptor->time = 0;
+		descriptor->flags = RING_DESC_POSTED | RING_DESC_INTERRUPT;
+		if (ring->is_tx) {
+			descriptor->length = frame->size;
+			descriptor->eof = frame->eof;
+			descriptor->sof = frame->sof;
+		}
+		ring->head = (ring->head + 1) % ring->size;
+		if (ring->is_tx)
+			ring_iowrite_prod(ring, ring->head);
+		else
+			ring_iowrite_cons(ring, ring->head);
+	}
+}
+
+/**
+ * ring_work() - progress completed frames
+ *
+ * If the ring is shutting down then all frames are marked as canceled and
+ * their callbacks are invoked.
+ *
+ * Otherwise we collect all completed frame from the ring buffer, write new
+ * frame to the ring buffer and invoke the callbacks for the completed frames.
+ */
+static void ring_work(struct work_struct *work)
+{
+	struct tb_ring *ring = container_of(work, typeof(*ring), work);
+	struct ring_frame *frame;
+	bool canceled = false;
+	unsigned long flags;
+	LIST_HEAD(done);
+
+	spin_lock_irqsave(&ring->lock, flags);
+
+	if (!ring->running) {
+		/*  Move all frames to done and mark them as canceled. */
+		list_splice_tail_init(&ring->in_flight, &done);
+		list_splice_tail_init(&ring->queue, &done);
+		canceled = true;
+		goto invoke_callback;
+	}
+
+	while (!ring_empty(ring)) {
+		if (!(ring->descriptors[ring->tail].flags
+				& RING_DESC_COMPLETED))
+			break;
+		frame = list_first_entry(&ring->in_flight, typeof(*frame),
+					 list);
+		list_move_tail(&frame->list, &done);
+		if (!ring->is_tx) {
+			frame->size = ring->descriptors[ring->tail].length;
+			frame->eof = ring->descriptors[ring->tail].eof;
+			frame->sof = ring->descriptors[ring->tail].sof;
+			frame->flags = ring->descriptors[ring->tail].flags;
+		}
+		ring->tail = (ring->tail + 1) % ring->size;
+	}
+	ring_write_descriptors(ring);
+
+invoke_callback:
+	/* allow callbacks to schedule new work */
+	spin_unlock_irqrestore(&ring->lock, flags);
+	while (!list_empty(&done)) {
+		frame = list_first_entry(&done, typeof(*frame), list);
+		/*
+		 * The callback may reenqueue or delete frame.
+		 * Do not hold on to it.
+		 */
+		list_del_init(&frame->list);
+		if (frame->callback)
+			frame->callback(ring, frame, canceled);
+	}
+}
+
+int __tb_ring_enqueue(struct tb_ring *ring, struct ring_frame *frame)
+{
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&ring->lock, flags);
+	if (ring->running) {
+		list_add_tail(&frame->list, &ring->queue);
+		ring_write_descriptors(ring);
+	} else {
+		ret = -ESHUTDOWN;
+	}
+	spin_unlock_irqrestore(&ring->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__tb_ring_enqueue);
+
+/**
+ * tb_ring_poll() - Poll one completed frame from the ring
+ * @ring: Ring to poll
+ *
+ * This function can be called when @start_poll callback of the @ring
+ * has been called. It will read one completed frame from the ring and
+ * return it to the caller. Returns %NULL if there is no more completed
+ * frames.
+ */
+struct ring_frame *tb_ring_poll(struct tb_ring *ring)
+{
+	struct ring_frame *frame = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ring->lock, flags);
+	if (!ring->running)
+		goto unlock;
+	if (ring_empty(ring))
+		goto unlock;
+
+	if (ring->descriptors[ring->tail].flags & RING_DESC_COMPLETED) {
+		frame = list_first_entry(&ring->in_flight, typeof(*frame),
+					 list);
+		list_del_init(&frame->list);
+
+		if (!ring->is_tx) {
+			frame->size = ring->descriptors[ring->tail].length;
+			frame->eof = ring->descriptors[ring->tail].eof;
+			frame->sof = ring->descriptors[ring->tail].sof;
+			frame->flags = ring->descriptors[ring->tail].flags;
+		}
+
+		ring->tail = (ring->tail + 1) % ring->size;
+	}
+
+unlock:
+	spin_unlock_irqrestore(&ring->lock, flags);
+	return frame;
+}
+EXPORT_SYMBOL_GPL(tb_ring_poll);
+
+static void __ring_interrupt_mask(struct tb_ring *ring, bool mask)
+{
+	int idx = ring_interrupt_index(ring);
+	int reg = REG_RING_INTERRUPT_BASE + idx / 32 * 4;
+	int bit = idx % 32;
+	u32 val;
+
+	val = ioread32(ring->nhi->iobase + reg);
+	if (mask)
+		val &= ~BIT(bit);
+	else
+		val |= BIT(bit);
+	iowrite32(val, ring->nhi->iobase + reg);
+}
+
+/* Both @nhi->lock and @ring->lock should be held */
+static void __ring_interrupt(struct tb_ring *ring)
+{
+	if (!ring->running)
+		return;
+
+	if (ring->start_poll) {
+		__ring_interrupt_mask(ring, true);
+		ring->start_poll(ring->poll_data);
+	} else {
+		schedule_work(&ring->work);
+	}
+}
+
+/**
+ * tb_ring_poll_complete() - Re-start interrupt for the ring
+ * @ring: Ring to re-start the interrupt
+ *
+ * This will re-start (unmask) the ring interrupt once the user is done
+ * with polling.
+ */
+void tb_ring_poll_complete(struct tb_ring *ring)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ring->nhi->lock, flags);
+	spin_lock(&ring->lock);
+	if (ring->start_poll)
+		__ring_interrupt_mask(ring, false);
+	spin_unlock(&ring->lock);
+	spin_unlock_irqrestore(&ring->nhi->lock, flags);
+}
+EXPORT_SYMBOL_GPL(tb_ring_poll_complete);
+
+static irqreturn_t ring_msix(int irq, void *data)
+{
+	struct tb_ring *ring = data;
+
+	spin_lock(&ring->nhi->lock);
+	spin_lock(&ring->lock);
+	__ring_interrupt(ring);
+	spin_unlock(&ring->lock);
+	spin_unlock(&ring->nhi->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int ring_request_msix(struct tb_ring *ring, bool no_suspend)
+{
+	struct tb_nhi *nhi = ring->nhi;
+	unsigned long irqflags;
+	int ret;
+
+	if (!nhi->pdev->msix_enabled)
+		return 0;
+
+	ret = ida_simple_get(&nhi->msix_ida, 0, MSIX_MAX_VECS, GFP_KERNEL);
+	if (ret < 0)
+		return ret;
+
+	ring->vector = ret;
+
+	ret = pci_irq_vector(ring->nhi->pdev, ring->vector);
+	if (ret < 0)
+		goto err_ida_remove;
+
+	ring->irq = ret;
+
+	irqflags = no_suspend ? IRQF_NO_SUSPEND : 0;
+	ret = request_irq(ring->irq, ring_msix, irqflags, "thunderbolt", ring);
+	if (ret)
+		goto err_ida_remove;
+
+	return 0;
+
+err_ida_remove:
+	ida_simple_remove(&nhi->msix_ida, ring->vector);
+
+	return ret;
+}
+
+static void ring_release_msix(struct tb_ring *ring)
+{
+	if (ring->irq <= 0)
+		return;
+
+	free_irq(ring->irq, ring);
+	ida_simple_remove(&ring->nhi->msix_ida, ring->vector);
+	ring->vector = 0;
+	ring->irq = 0;
+}
+
+static int nhi_alloc_hop(struct tb_nhi *nhi, struct tb_ring *ring)
+{
+	int ret = 0;
+
+	spin_lock_irq(&nhi->lock);
+
+	if (ring->hop < 0) {
+		unsigned int i;
+
+		/*
+		 * Automatically allocate HopID from the non-reserved
+		 * range 8 .. hop_count - 1.
+		 */
+		for (i = RING_FIRST_USABLE_HOPID; i < nhi->hop_count; i++) {
+			if (ring->is_tx) {
+				if (!nhi->tx_rings[i]) {
+					ring->hop = i;
+					break;
+				}
+			} else {
+				if (!nhi->rx_rings[i]) {
+					ring->hop = i;
+					break;
+				}
+			}
+		}
+	}
+
+	if (ring->hop < 0 || ring->hop >= nhi->hop_count) {
+		dev_warn(&nhi->pdev->dev, "invalid hop: %d\n", ring->hop);
+		ret = -EINVAL;
+		goto err_unlock;
+	}
+	if (ring->is_tx && nhi->tx_rings[ring->hop]) {
+		dev_warn(&nhi->pdev->dev, "TX hop %d already allocated\n",
+			 ring->hop);
+		ret = -EBUSY;
+		goto err_unlock;
+	} else if (!ring->is_tx && nhi->rx_rings[ring->hop]) {
+		dev_warn(&nhi->pdev->dev, "RX hop %d already allocated\n",
+			 ring->hop);
+		ret = -EBUSY;
+		goto err_unlock;
+	}
+
+	if (ring->is_tx)
+		nhi->tx_rings[ring->hop] = ring;
+	else
+		nhi->rx_rings[ring->hop] = ring;
+
+err_unlock:
+	spin_unlock_irq(&nhi->lock);
+
+	return ret;
+}
+
+static struct tb_ring *tb_ring_alloc(struct tb_nhi *nhi, u32 hop, int size,
+				     bool transmit, unsigned int flags,
+				     u16 sof_mask, u16 eof_mask,
+				     void (*start_poll)(void *),
+				     void *poll_data)
+{
+	struct tb_ring *ring = NULL;
+	dev_info(&nhi->pdev->dev, "allocating %s ring %d of size %d\n",
+		 transmit ? "TX" : "RX", hop, size);
+
+	/* Tx Ring 2 is reserved for E2E workaround */
+	if (transmit && hop == RING_E2E_UNUSED_HOPID)
+		return NULL;
+
+	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
+	if (!ring)
+		return NULL;
+
+	spin_lock_init(&ring->lock);
+	INIT_LIST_HEAD(&ring->queue);
+	INIT_LIST_HEAD(&ring->in_flight);
+	INIT_WORK(&ring->work, ring_work);
+
+	ring->nhi = nhi;
+	ring->hop = hop;
+	ring->is_tx = transmit;
+	ring->size = size;
+	ring->flags = flags;
+	ring->sof_mask = sof_mask;
+	ring->eof_mask = eof_mask;
+	ring->head = 0;
+	ring->tail = 0;
+	ring->running = false;
+	ring->start_poll = start_poll;
+	ring->poll_data = poll_data;
+
+	ring->descriptors = dma_alloc_coherent(&ring->nhi->pdev->dev,
+			size * sizeof(*ring->descriptors),
+			&ring->descriptors_dma, GFP_KERNEL | __GFP_ZERO);
+	if (!ring->descriptors)
+		goto err_free_ring;
+
+	if (ring_request_msix(ring, flags & RING_FLAG_NO_SUSPEND))
+		goto err_free_descs;
+
+	if (nhi_alloc_hop(nhi, ring))
+		goto err_release_msix;
+
+	return ring;
+
+err_release_msix:
+	ring_release_msix(ring);
+err_free_descs:
+	dma_free_coherent(&ring->nhi->pdev->dev,
+			  ring->size * sizeof(*ring->descriptors),
+			  ring->descriptors, ring->descriptors_dma);
+err_free_ring:
+	kfree(ring);
+
+	return NULL;
+}
+
+/**
+ * tb_ring_alloc_tx() - Allocate DMA ring for transmit
+ * @nhi: Pointer to the NHI the ring is to be allocated
+ * @hop: HopID (ring) to allocate
+ * @size: Number of entries in the ring
+ * @flags: Flags for the ring
+ */
+struct tb_ring *tb_ring_alloc_tx(struct tb_nhi *nhi, int hop, int size,
+				 unsigned int flags)
+{
+	return tb_ring_alloc(nhi, hop, size, true, flags, 0, 0, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(tb_ring_alloc_tx);
+
+/**
+ * tb_ring_alloc_rx() - Allocate DMA ring for receive
+ * @nhi: Pointer to the NHI the ring is to be allocated
+ * @hop: HopID (ring) to allocate. Pass %-1 for automatic allocation.
+ * @size: Number of entries in the ring
+ * @flags: Flags for the ring
+ * @sof_mask: Mask of PDF values that start a frame
+ * @eof_mask: Mask of PDF values that end a frame
+ * @start_poll: If not %NULL the ring will call this function when an
+ *		interrupt is triggered and masked, instead of callback
+ *		in each Rx frame.
+ * @poll_data: Optional data passed to @start_poll
+ */
+struct tb_ring *tb_ring_alloc_rx(struct tb_nhi *nhi, int hop, int size,
+				 unsigned int flags, u16 sof_mask, u16 eof_mask,
+				 void (*start_poll)(void *), void *poll_data)
+{
+	return tb_ring_alloc(nhi, hop, size, false, flags, sof_mask, eof_mask,
+			     start_poll, poll_data);
+}
+EXPORT_SYMBOL_GPL(tb_ring_alloc_rx);
+
+/**
+ * tb_ring_start() - enable a ring
+ *
+ * Must not be invoked in parallel with tb_ring_stop().
+ */
+void tb_ring_start(struct tb_ring *ring)
+{
+	u16 frame_size;
+	u32 flags;
+
+	spin_lock_irq(&ring->nhi->lock);
+	spin_lock(&ring->lock);
+	if (ring->nhi->going_away)
+		goto err;
+	if (ring->running) {
+		dev_WARN(&ring->nhi->pdev->dev, "ring already started\n");
+		goto err;
+	}
+	dev_info(&ring->nhi->pdev->dev, "starting %s %d\n",
+		 RING_TYPE(ring), ring->hop);
+
+	if (ring->flags & RING_FLAG_FRAME) {
+		/* Means 4096 */
+		frame_size = 0;
+		flags = RING_FLAG_ENABLE;
+	} else {
+		frame_size = TB_FRAME_SIZE;
+		flags = RING_FLAG_ENABLE | RING_FLAG_RAW;
+	}
+
+	if (ring->flags & RING_FLAG_E2E && !ring->is_tx) {
+		u32 hop;
+
+		/*
+		 * In order not to lose Rx packets we enable end-to-end
+		 * workaround which transfers Rx credits to an unused Tx
+		 * HopID.
+		 */
+		hop = RING_E2E_UNUSED_HOPID << REG_RX_OPTIONS_E2E_HOP_SHIFT;
+		hop &= REG_RX_OPTIONS_E2E_HOP_MASK;
+		flags |= hop | RING_FLAG_E2E_FLOW_CONTROL;
+	}
+
+	ring_iowrite64desc(ring, ring->descriptors_dma, 0);
+	if (ring->is_tx) {
+		ring_iowrite32desc(ring, ring->size, 12);
+		ring_iowrite32options(ring, 0, 4); /* time releated ? */
+		ring_iowrite32options(ring, flags, 0);
+	} else {
+		u32 sof_eof_mask = ring->sof_mask << 16 | ring->eof_mask;
+
+		ring_iowrite32desc(ring, (frame_size << 16) | ring->size, 12);
+		ring_iowrite32options(ring, sof_eof_mask, 4);
+		ring_iowrite32options(ring, flags, 0);
+	}
+	ring_interrupt_active(ring, true);
+	ring->running = true;
+err:
+	spin_unlock(&ring->lock);
+	spin_unlock_irq(&ring->nhi->lock);
+}
+EXPORT_SYMBOL_GPL(tb_ring_start);
+
+/**
+ * tb_ring_stop() - shutdown a ring
+ *
+ * Must not be invoked from a callback.
+ *
+ * This method will disable the ring. Further calls to
+ * tb_ring_tx/tb_ring_rx will return -ESHUTDOWN until ring_stop has been
+ * called.
+ *
+ * All enqueued frames will be canceled and their callbacks will be executed
+ * with frame->canceled set to true (on the callback thread). This method
+ * returns only after all callback invocations have finished.
+ */
+void tb_ring_stop(struct tb_ring *ring)
+{
+	spin_lock_irq(&ring->nhi->lock);
+	spin_lock(&ring->lock);
+	dev_info(&ring->nhi->pdev->dev, "stopping %s %d\n",
+		 RING_TYPE(ring), ring->hop);
+	if (ring->nhi->going_away)
+		goto err;
+	if (!ring->running) {
+		dev_WARN(&ring->nhi->pdev->dev, "%s %d already stopped\n",
+			 RING_TYPE(ring), ring->hop);
+		goto err;
+	}
+	ring_interrupt_active(ring, false);
+
+	ring_iowrite32options(ring, 0, 0);
+	ring_iowrite64desc(ring, 0, 0);
+	ring_iowrite32desc(ring, 0, 8);
+	ring_iowrite32desc(ring, 0, 12);
+	ring->head = 0;
+	ring->tail = 0;
+	ring->running = false;
+
+err:
+	spin_unlock(&ring->lock);
+	spin_unlock_irq(&ring->nhi->lock);
+
+	/*
+	 * schedule ring->work to invoke callbacks on all remaining frames.
+	 */
+	schedule_work(&ring->work);
+	flush_work(&ring->work);
+}
+EXPORT_SYMBOL_GPL(tb_ring_stop);
+
+/*
+ * tb_ring_free() - free ring
+ *
+ * When this method returns all invocations of ring->callback will have
+ * finished.
+ *
+ * Ring must be stopped.
+ *
+ * Must NOT be called from ring_frame->callback!
+ */
+void tb_ring_free(struct tb_ring *ring)
+{
+	spin_lock_irq(&ring->nhi->lock);
+	/*
+	 * Dissociate the ring from the NHI. This also ensures that
+	 * nhi_interrupt_work cannot reschedule ring->work.
+	 */
+	if (ring->is_tx)
+		ring->nhi->tx_rings[ring->hop] = NULL;
+	else
+		ring->nhi->rx_rings[ring->hop] = NULL;
+
+	if (ring->running) {
+		dev_WARN(&ring->nhi->pdev->dev, "%s %d still running\n",
+			 RING_TYPE(ring), ring->hop);
+	}
+	spin_unlock_irq(&ring->nhi->lock);
+
+	ring_release_msix(ring);
+
+	dma_free_coherent(&ring->nhi->pdev->dev,
+			  ring->size * sizeof(*ring->descriptors),
+			  ring->descriptors, ring->descriptors_dma);
+
+	ring->descriptors = NULL;
+	ring->descriptors_dma = 0;
+
+
+	dev_info(&ring->nhi->pdev->dev,
+		 "freeing %s %d\n",
+		 RING_TYPE(ring),
+		 ring->hop);
+
+	/**
+	 * ring->work can no longer be scheduled (it is scheduled only
+	 * by nhi_interrupt_work, ring_stop and ring_msix). Wait for it
+	 * to finish before freeing the ring.
+	 */
+	flush_work(&ring->work);
+	kfree(ring);
+}
+EXPORT_SYMBOL_GPL(tb_ring_free);
+
+/**
+ * nhi_mailbox_cmd() - Send a command through NHI mailbox
+ * @nhi: Pointer to the NHI structure
+ * @cmd: Command to send
+ * @data: Data to be send with the command
+ *
+ * Sends mailbox command to the firmware running on NHI. Returns %0 in
+ * case of success and negative errno in case of failure.
+ */
+int nhi_mailbox_cmd(struct tb_nhi *nhi, enum nhi_mailbox_cmd cmd, u32 data)
+{
+	ktime_t timeout;
+	u32 val;
+
+	iowrite32(data, nhi->iobase + REG_INMAIL_DATA);
+
+	val = ioread32(nhi->iobase + REG_INMAIL_CMD);
+	val &= ~(REG_INMAIL_CMD_MASK | REG_INMAIL_ERROR);
+	val |= REG_INMAIL_OP_REQUEST | cmd;
+	iowrite32(val, nhi->iobase + REG_INMAIL_CMD);
+
+	timeout = ktime_add_ms(ktime_get(), NHI_MAILBOX_TIMEOUT);
+	do {
+		val = ioread32(nhi->iobase + REG_INMAIL_CMD);
+		if (!(val & REG_INMAIL_OP_REQUEST))
+			break;
+		usleep_range(10, 20);
+	} while (ktime_before(ktime_get(), timeout));
+
+	if (val & REG_INMAIL_OP_REQUEST)
+		return -ETIMEDOUT;
+	if (val & REG_INMAIL_ERROR)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * nhi_mailbox_mode() - Return current firmware operation mode
+ * @nhi: Pointer to the NHI structure
+ *
+ * The function reads current firmware operation mode using NHI mailbox
+ * registers and returns it to the caller.
+ */
+enum nhi_fw_mode nhi_mailbox_mode(struct tb_nhi *nhi)
+{
+	u32 val;
+
+	val = ioread32(nhi->iobase + REG_OUTMAIL_CMD);
+	val &= REG_OUTMAIL_CMD_OPMODE_MASK;
+	val >>= REG_OUTMAIL_CMD_OPMODE_SHIFT;
+
+	return (enum nhi_fw_mode)val;
+}
+
+static void nhi_interrupt_work(struct work_struct *work)
+{
+	struct tb_nhi *nhi = container_of(work, typeof(*nhi), interrupt_work);
+	int value = 0; /* Suppress uninitialized usage warning. */
+	int bit;
+	int hop = -1;
+	int type = 0; /* current interrupt type 0: TX, 1: RX, 2: RX overflow */
+	struct tb_ring *ring;
+
+	spin_lock_irq(&nhi->lock);
+
+	/*
+	 * Starting at REG_RING_NOTIFY_BASE there are three status bitfields
+	 * (TX, RX, RX overflow). We iterate over the bits and read a new
+	 * dwords as required. The registers are cleared on read.
+	 */
+	for (bit = 0; bit < 3 * nhi->hop_count; bit++) {
+		if (bit % 32 == 0)
+			value = ioread32(nhi->iobase
+					 + REG_RING_NOTIFY_BASE
+					 + 4 * (bit / 32));
+		if (++hop == nhi->hop_count) {
+			hop = 0;
+			type++;
+		}
+		if ((value & (1 << (bit % 32))) == 0)
+			continue;
+		if (type == 2) {
+			dev_warn(&nhi->pdev->dev,
+				 "RX overflow for ring %d\n",
+				 hop);
+			continue;
+		}
+		if (type == 0)
+			ring = nhi->tx_rings[hop];
+		else
+			ring = nhi->rx_rings[hop];
+		if (ring == NULL) {
+			dev_warn(&nhi->pdev->dev,
+				 "got interrupt for inactive %s ring %d\n",
+				 type ? "RX" : "TX",
+				 hop);
+			continue;
+		}
+
+		spin_lock(&ring->lock);
+		__ring_interrupt(ring);
+		spin_unlock(&ring->lock);
+	}
+	spin_unlock_irq(&nhi->lock);
+}
+
+static irqreturn_t nhi_msi(int irq, void *data)
+{
+	struct tb_nhi *nhi = data;
+	schedule_work(&nhi->interrupt_work);
+	return IRQ_HANDLED;
+}
+
+static int nhi_suspend_noirq(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct tb *tb = pci_get_drvdata(pdev);
+
+	return tb_domain_suspend_noirq(tb);
+}
+
+static void nhi_enable_int_throttling(struct tb_nhi *nhi)
+{
+	/* Throttling is specified in 256ns increments */
+	u32 throttle = DIV_ROUND_UP(128 * NSEC_PER_USEC, 256);
+	unsigned int i;
+
+	/*
+	 * Configure interrupt throttling for all vectors even if we
+	 * only use few.
+	 */
+	for (i = 0; i < MSIX_MAX_VECS; i++) {
+		u32 reg = REG_INT_THROTTLING_RATE + i * 4;
+		iowrite32(throttle, nhi->iobase + reg);
+	}
+}
+
+static int nhi_resume_noirq(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct tb *tb = pci_get_drvdata(pdev);
+
+	/*
+	 * Check that the device is still there. It may be that the user
+	 * unplugged last device which causes the host controller to go
+	 * away on PCs.
+	 */
+	if (!pci_device_is_present(pdev))
+		tb->nhi->going_away = true;
+	else
+		nhi_enable_int_throttling(tb->nhi);
+
+	return tb_domain_resume_noirq(tb);
+}
+
+static int nhi_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct tb *tb = pci_get_drvdata(pdev);
+
+	return tb_domain_suspend(tb);
+}
+
+static void nhi_complete(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct tb *tb = pci_get_drvdata(pdev);
+
+	/*
+	 * If we were runtime suspended when system suspend started,
+	 * schedule runtime resume now. It should bring the domain back
+	 * to functional state.
+	 */
+	if (pm_runtime_suspended(&pdev->dev))
+		pm_runtime_resume(&pdev->dev);
+	else
+		tb_domain_complete(tb);
+}
+
+static int nhi_runtime_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct tb *tb = pci_get_drvdata(pdev);
+
+	return tb_domain_runtime_suspend(tb);
+}
+
+static int nhi_runtime_resume(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct tb *tb = pci_get_drvdata(pdev);
+
+	nhi_enable_int_throttling(tb->nhi);
+	return tb_domain_runtime_resume(tb);
+}
+
+static void nhi_shutdown(struct tb_nhi *nhi)
+{
+	int i;
+	dev_info(&nhi->pdev->dev, "shutdown\n");
+
+	for (i = 0; i < nhi->hop_count; i++) {
+		if (nhi->tx_rings[i])
+			dev_WARN(&nhi->pdev->dev,
+				 "TX ring %d is still active\n", i);
+		if (nhi->rx_rings[i])
+			dev_WARN(&nhi->pdev->dev,
+				 "RX ring %d is still active\n", i);
+	}
+	nhi_disable_interrupts(nhi);
+	/*
+	 * We have to release the irq before calling flush_work. Otherwise an
+	 * already executing IRQ handler could call schedule_work again.
+	 */
+	if (!nhi->pdev->msix_enabled) {
+		devm_free_irq(&nhi->pdev->dev, nhi->pdev->irq, nhi);
+		flush_work(&nhi->interrupt_work);
+	}
+	ida_destroy(&nhi->msix_ida);
+}
+
+static int nhi_init_msi(struct tb_nhi *nhi)
+{
+	struct pci_dev *pdev = nhi->pdev;
+	int res, irq, nvec;
+
+	/* In case someone left them on. */
+	nhi_disable_interrupts(nhi);
+
+	nhi_enable_int_throttling(nhi);
+
+	ida_init(&nhi->msix_ida);
+
+	/*
+	 * The NHI has 16 MSI-X vectors or a single MSI. We first try to
+	 * get all MSI-X vectors and if we succeed, each ring will have
+	 * one MSI-X. If for some reason that does not work out, we
+	 * fallback to a single MSI.
+	 */
+	nvec = pci_alloc_irq_vectors(pdev, MSIX_MIN_VECS, MSIX_MAX_VECS,
+				     PCI_IRQ_MSIX);
+	if (nvec < 0) {
+		nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
+		if (nvec < 0)
+			return nvec;
+
+		INIT_WORK(&nhi->interrupt_work, nhi_interrupt_work);
+
+		irq = pci_irq_vector(nhi->pdev, 0);
+		if (irq < 0)
+			return irq;
+
+		res = devm_request_irq(&pdev->dev, irq, nhi_msi,
+				       IRQF_NO_SUSPEND, "thunderbolt", nhi);
+		if (res) {
+			dev_err(&pdev->dev, "request_irq failed, aborting\n");
+			return res;
+		}
+	}
+
+	return 0;
+}
+
+static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct tb_nhi *nhi;
+	struct tb *tb;
+	int res;
+
+	res = pcim_enable_device(pdev);
+	if (res) {
+		dev_err(&pdev->dev, "cannot enable PCI device, aborting\n");
+		return res;
+	}
+
+	res = pcim_iomap_regions(pdev, 1 << 0, "thunderbolt");
+	if (res) {
+		dev_err(&pdev->dev, "cannot obtain PCI resources, aborting\n");
+		return res;
+	}
+
+	nhi = devm_kzalloc(&pdev->dev, sizeof(*nhi), GFP_KERNEL);
+	if (!nhi)
+		return -ENOMEM;
+
+	nhi->pdev = pdev;
+	/* cannot fail - table is allocated bin pcim_iomap_regions */
+	nhi->iobase = pcim_iomap_table(pdev)[0];
+	nhi->hop_count = ioread32(nhi->iobase + REG_HOP_COUNT) & 0x3ff;
+	if (nhi->hop_count != 12 && nhi->hop_count != 32)
+		dev_warn(&pdev->dev, "unexpected hop count: %d\n",
+			 nhi->hop_count);
+
+	nhi->tx_rings = devm_kcalloc(&pdev->dev, nhi->hop_count,
+				     sizeof(*nhi->tx_rings), GFP_KERNEL);
+	nhi->rx_rings = devm_kcalloc(&pdev->dev, nhi->hop_count,
+				     sizeof(*nhi->rx_rings), GFP_KERNEL);
+	if (!nhi->tx_rings || !nhi->rx_rings)
+		return -ENOMEM;
+
+	res = nhi_init_msi(nhi);
+	if (res) {
+		dev_err(&pdev->dev, "cannot enable MSI, aborting\n");
+		return res;
+	}
+
+	spin_lock_init(&nhi->lock);
+
+	res = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+	if (res)
+		res = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+	if (res) {
+		dev_err(&pdev->dev, "failed to set DMA mask\n");
+		return res;
+	}
+
+	pci_set_master(pdev);
+
+	tb = icm_probe(nhi);
+	if (!tb)
+		tb = tb_probe(nhi);
+	if (!tb) {
+		dev_err(&nhi->pdev->dev,
+			"failed to determine connection manager, aborting\n");
+		return -ENODEV;
+	}
+
+	dev_info(&nhi->pdev->dev, "NHI initialized, starting thunderbolt\n");
+
+	res = tb_domain_add(tb);
+	if (res) {
+		/*
+		 * At this point the RX/TX rings might already have been
+		 * activated. Do a proper shutdown.
+		 */
+		tb_domain_put(tb);
+		nhi_shutdown(nhi);
+		return res;
+	}
+	pci_set_drvdata(pdev, tb);
+
+	pm_runtime_allow(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, TB_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	return 0;
+}
+
+static void nhi_remove(struct pci_dev *pdev)
+{
+	struct tb *tb = pci_get_drvdata(pdev);
+	struct tb_nhi *nhi = tb->nhi;
+
+	pm_runtime_get_sync(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_forbid(&pdev->dev);
+
+	tb_domain_remove(tb);
+	nhi_shutdown(nhi);
+}
+
+/*
+ * The tunneled pci bridges are siblings of us. Use resume_noirq to reenable
+ * the tunnels asap. A corresponding pci quirk blocks the downstream bridges
+ * resume_noirq until we are done.
+ */
+static const struct dev_pm_ops nhi_pm_ops = {
+	.suspend_noirq = nhi_suspend_noirq,
+	.resume_noirq = nhi_resume_noirq,
+	.freeze_noirq = nhi_suspend_noirq, /*
+					    * we just disable hotplug, the
+					    * pci-tunnels stay alive.
+					    */
+	.thaw_noirq = nhi_resume_noirq,
+	.restore_noirq = nhi_resume_noirq,
+	.suspend = nhi_suspend,
+	.freeze = nhi_suspend,
+	.poweroff = nhi_suspend,
+	.complete = nhi_complete,
+	.runtime_suspend = nhi_runtime_suspend,
+	.runtime_resume = nhi_runtime_resume,
+};
+
+static struct pci_device_id nhi_ids[] = {
+	/*
+	 * We have to specify class, the TB bridges use the same device and
+	 * vendor (sub)id on gen 1 and gen 2 controllers.
+	 */
+	{
+		.class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0,
+		.vendor = PCI_VENDOR_ID_INTEL,
+		.device = PCI_DEVICE_ID_INTEL_LIGHT_RIDGE,
+		.subvendor = 0x2222, .subdevice = 0x1111,
+	},
+	{
+		.class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0,
+		.vendor = PCI_VENDOR_ID_INTEL,
+		.device = PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C,
+		.subvendor = 0x2222, .subdevice = 0x1111,
+	},
+	{
+		.class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0,
+		.vendor = PCI_VENDOR_ID_INTEL,
+		.device = PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_NHI,
+		.subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID,
+	},
+	{
+		.class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0,
+		.vendor = PCI_VENDOR_ID_INTEL,
+		.device = PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_NHI,
+		.subvendor = PCI_ANY_ID, .subdevice = PCI_ANY_ID,
+	},
+
+	/* Thunderbolt 3 */
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_USBONLY_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_USBONLY_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_USBONLY_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_TITAN_RIDGE_2C_NHI) },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_INTEL_TITAN_RIDGE_4C_NHI) },
+
+	{ 0,}
+};
+
+MODULE_DEVICE_TABLE(pci, nhi_ids);
+MODULE_LICENSE("GPL");
+
+static struct pci_driver nhi_driver = {
+	.name = "thunderbolt",
+	.id_table = nhi_ids,
+	.probe = nhi_probe,
+	.remove = nhi_remove,
+	.driver.pm = &nhi_pm_ops,
+};
+
+static int __init nhi_init(void)
+{
+	int ret;
+
+	ret = tb_domain_init();
+	if (ret)
+		return ret;
+	ret = pci_register_driver(&nhi_driver);
+	if (ret)
+		tb_domain_exit();
+	return ret;
+}
+
+static void __exit nhi_unload(void)
+{
+	pci_unregister_driver(&nhi_driver);
+	tb_domain_exit();
+}
+
+rootfs_initcall(nhi_init);
+module_exit(nhi_unload);