diff --git a/drivers/Kconfig b/drivers/Kconfig
index 0e87a34..9b2dcc2 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -176,4 +176,6 @@
 
 source "drivers/mcb/Kconfig"
 
+source "drivers/thunderbolt/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index f98b50d..37b9ed4 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -158,3 +158,4 @@
 obj-$(CONFIG_FMC)		+= fmc/
 obj-$(CONFIG_POWERCAP)		+= powercap/
 obj-$(CONFIG_MCB)		+= mcb/
+obj-$(CONFIG_THUNDERBOLT)	+= thunderbolt/
diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
new file mode 100644
index 0000000..3a255296
--- /dev/null
+++ b/drivers/thunderbolt/Kconfig
@@ -0,0 +1,12 @@
+menuconfig THUNDERBOLT
+	tristate "Thunderbolt support for Apple devices"
+	default no
+	help
+	  Cactus Ridge Thunderbolt Controller driver
+	  This driver is required if you want to hotplug Thunderbolt devices on
+	  Apple hardware.
+
+	  Device chaining is currently not supported.
+
+	  To compile this driver a module, choose M here. The module will be
+	  called thunderbolt.
diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
new file mode 100644
index 0000000..d473ab9
--- /dev/null
+++ b/drivers/thunderbolt/Makefile
@@ -0,0 +1,3 @@
+obj-${CONFIG_THUNDERBOLT} := thunderbolt.o
+thunderbolt-objs := nhi.o
+
diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
new file mode 100644
index 0000000..11070ff
--- /dev/null
+++ b/drivers/thunderbolt/nhi.c
@@ -0,0 +1,630 @@
+/*
+ * 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/slab.h>
+#include <linux/errno.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/dmi.h>
+
+#include "nhi.h"
+#include "nhi_regs.h"
+
+#define RING_TYPE(ring) ((ring)->is_tx ? "TX ring" : "RX ring")
+
+
+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;
+	int bit = ring_interrupt_index(ring) & 31;
+	int mask = 1 << bit;
+	u32 old, new;
+	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_iowrite16desc(struct tb_ring *ring, u32 value, u32 offset)
+{
+	iowrite16(value, ring_desc_base(ring) + offset);
+}
+
+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;
+		ring_iowrite16desc(ring, ring->head, ring->is_tx ? 10 : 8);
+	}
+}
+
+/**
+ * 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;
+	LIST_HEAD(done);
+	mutex_lock(&ring->lock);
+
+	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;
+			if (frame->sof != 0)
+				dev_WARN(&ring->nhi->pdev->dev,
+					 "%s %d got unexpected SOF: %#x\n",
+					 RING_TYPE(ring), ring->hop,
+					 frame->sof);
+			/*
+			 * known flags:
+			 * raw not enabled, interupt not set: 0x2=0010
+			 * raw enabled: 0xa=1010
+			 * raw not enabled: 0xb=1011
+			 * partial frame (>MAX_FRAME_SIZE): 0xe=1110
+			 */
+			if (frame->flags != 0xa)
+				dev_WARN(&ring->nhi->pdev->dev,
+					 "%s %d got unexpected flags: %#x\n",
+					 RING_TYPE(ring), ring->hop,
+					 frame->flags);
+		}
+		ring->tail = (ring->tail + 1) % ring->size;
+	}
+	ring_write_descriptors(ring);
+
+invoke_callback:
+	mutex_unlock(&ring->lock); /* allow callbacks to schedule new work */
+	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);
+		frame->callback(ring, frame, canceled);
+	}
+}
+
+int __ring_enqueue(struct tb_ring *ring, struct ring_frame *frame)
+{
+	int ret = 0;
+	mutex_lock(&ring->lock);
+	if (ring->running) {
+		list_add_tail(&frame->list, &ring->queue);
+		ring_write_descriptors(ring);
+	} else {
+		ret = -ESHUTDOWN;
+	}
+	mutex_unlock(&ring->lock);
+	return ret;
+}
+
+static struct tb_ring *ring_alloc(struct tb_nhi *nhi, u32 hop, int size,
+				  bool transmit)
+{
+	struct tb_ring *ring = NULL;
+	dev_info(&nhi->pdev->dev, "allocating %s ring %d of size %d\n",
+		 transmit ? "TX" : "RX", hop, size);
+
+	mutex_lock(&nhi->lock);
+	if (hop >= nhi->hop_count) {
+		dev_WARN(&nhi->pdev->dev, "invalid hop: %d\n", hop);
+		goto err;
+	}
+	if (transmit && nhi->tx_rings[hop]) {
+		dev_WARN(&nhi->pdev->dev, "TX hop %d already allocated\n", hop);
+		goto err;
+	} else if (!transmit && nhi->rx_rings[hop]) {
+		dev_WARN(&nhi->pdev->dev, "RX hop %d already allocated\n", hop);
+		goto err;
+	}
+	ring = kzalloc(sizeof(*ring), GFP_KERNEL);
+	if (!ring)
+		goto err;
+
+	mutex_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->head = 0;
+	ring->tail = 0;
+	ring->running = false;
+	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;
+
+	if (transmit)
+		nhi->tx_rings[hop] = ring;
+	else
+		nhi->rx_rings[hop] = ring;
+	mutex_unlock(&nhi->lock);
+	return ring;
+
+err:
+	if (ring)
+		mutex_destroy(&ring->lock);
+	kfree(ring);
+	mutex_unlock(&nhi->lock);
+	return NULL;
+}
+
+struct tb_ring *ring_alloc_tx(struct tb_nhi *nhi, int hop, int size)
+{
+	return ring_alloc(nhi, hop, size, true);
+}
+
+struct tb_ring *ring_alloc_rx(struct tb_nhi *nhi, int hop, int size)
+{
+	return ring_alloc(nhi, hop, size, false);
+}
+
+/**
+ * ring_start() - enable a ring
+ *
+ * Must not be invoked in parallel with ring_stop().
+ */
+void ring_start(struct tb_ring *ring)
+{
+	mutex_lock(&ring->nhi->lock);
+	mutex_lock(&ring->lock);
+	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);
+
+	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,
+				      RING_FLAG_ENABLE | RING_FLAG_RAW, 0);
+	} else {
+		ring_iowrite32desc(ring,
+				   (TB_FRAME_SIZE << 16) | ring->size, 12);
+		ring_iowrite32options(ring, 0xffffffff, 4); /* SOF EOF mask */
+		ring_iowrite32options(ring,
+				      RING_FLAG_ENABLE | RING_FLAG_RAW, 0);
+	}
+	ring_interrupt_active(ring, true);
+	ring->running = true;
+err:
+	mutex_unlock(&ring->lock);
+	mutex_unlock(&ring->nhi->lock);
+}
+
+
+/**
+ * ring_stop() - shutdown a ring
+ *
+ * Must not be invoked from a callback.
+ *
+ * This method will disable the ring. Further calls to ring_tx/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 ring_stop(struct tb_ring *ring)
+{
+	mutex_lock(&ring->nhi->lock);
+	mutex_lock(&ring->lock);
+	dev_info(&ring->nhi->pdev->dev, "stopping %s %d\n",
+		 RING_TYPE(ring), ring->hop);
+	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_iowrite16desc(ring, 0, ring->is_tx ? 10 : 8);
+	ring_iowrite32desc(ring, 0, 12);
+	ring->head = 0;
+	ring->tail = 0;
+	ring->running = false;
+
+err:
+	mutex_unlock(&ring->lock);
+	mutex_unlock(&ring->nhi->lock);
+
+	/*
+	 * schedule ring->work to invoke callbacks on all remaining frames.
+	 */
+	schedule_work(&ring->work);
+	flush_work(&ring->work);
+}
+
+/*
+ * 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 ring_free(struct tb_ring *ring)
+{
+	mutex_lock(&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);
+	}
+
+	dma_free_coherent(&ring->nhi->pdev->dev,
+			  ring->size * sizeof(*ring->descriptors),
+			  ring->descriptors, ring->descriptors_dma);
+
+	ring->descriptors = 0;
+	ring->descriptors_dma = 0;
+
+
+	dev_info(&ring->nhi->pdev->dev,
+		 "freeing %s %d\n",
+		 RING_TYPE(ring),
+		 ring->hop);
+
+	mutex_unlock(&ring->nhi->lock);
+	/**
+	 * ring->work can no longer be scheduled (it is scheduled only by
+	 * nhi_interrupt_work and ring_stop). Wait for it to finish before
+	 * freeing the ring.
+	 */
+	flush_work(&ring->work);
+	mutex_destroy(&ring->lock);
+	kfree(ring);
+}
+
+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;
+
+	mutex_lock(&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;
+		}
+		/* we do not check ring->running, this is done in ring->work */
+		schedule_work(&ring->work);
+	}
+	mutex_unlock(&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 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.
+	 */
+	devm_free_irq(&nhi->pdev->dev, nhi->pdev->irq, nhi);
+	flush_work(&nhi->interrupt_work);
+	mutex_destroy(&nhi->lock);
+}
+
+static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct tb_nhi *nhi;
+	int res;
+
+	res = pcim_enable_device(pdev);
+	if (res) {
+		dev_err(&pdev->dev, "cannot enable PCI device, aborting\n");
+		return res;
+	}
+
+	res = pci_enable_msi(pdev);
+	if (res) {
+		dev_err(&pdev->dev, "cannot enable MSI, 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)
+		dev_warn(&pdev->dev, "unexpected hop count: %d\n",
+			 nhi->hop_count);
+	INIT_WORK(&nhi->interrupt_work, nhi_interrupt_work);
+
+	nhi->tx_rings = devm_kzalloc(&pdev->dev,
+				     nhi->hop_count * sizeof(struct tb_ring),
+				     GFP_KERNEL);
+	nhi->rx_rings = devm_kzalloc(&pdev->dev,
+				     nhi->hop_count * sizeof(struct tb_ring),
+				     GFP_KERNEL);
+	if (!nhi->tx_rings || !nhi->rx_rings)
+		return -ENOMEM;
+
+	nhi_disable_interrupts(nhi); /* In case someone left them on. */
+	res = devm_request_irq(&pdev->dev, pdev->irq, nhi_msi,
+			       IRQF_NO_SUSPEND, /* must work during _noirq */
+			       "thunderbolt", nhi);
+	if (res) {
+		dev_err(&pdev->dev, "request_irq failed, aborting\n");
+		return res;
+	}
+
+	mutex_init(&nhi->lock);
+
+	pci_set_master(pdev);
+
+	/* magic value - clock related? */
+	iowrite32(3906250 / 10000, nhi->iobase + 0x38c00);
+
+	pci_set_drvdata(pdev, nhi);
+
+	return 0;
+}
+
+static void nhi_remove(struct pci_dev *pdev)
+{
+	struct tb_nhi *nhi = pci_get_drvdata(pdev);
+	nhi_shutdown(nhi);
+}
+
+struct pci_device_id nhi_ids[] = {
+	/*
+	 * We have to specify class, the TB bridges use the same device and
+	 * vendor (sub)id.
+	 */
+	{
+		.class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0,
+		.vendor = PCI_VENDOR_ID_INTEL, .device = 0x1547,
+		.subvendor = 0x2222, .subdevice = 0x1111,
+	},
+	{
+		.class = PCI_CLASS_SYSTEM_OTHER << 8, .class_mask = ~0,
+		.vendor = PCI_VENDOR_ID_INTEL, .device = 0x156c,
+		.subvendor = 0x2222, .subdevice = 0x1111,
+	},
+	{ 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,
+};
+
+static int __init nhi_init(void)
+{
+	if (!dmi_match(DMI_BOARD_VENDOR, "Apple Inc."))
+		return -ENOSYS;
+	return pci_register_driver(&nhi_driver);
+}
+
+static void __exit nhi_unload(void)
+{
+	pci_unregister_driver(&nhi_driver);
+}
+
+module_init(nhi_init);
+module_exit(nhi_unload);
diff --git a/drivers/thunderbolt/nhi.h b/drivers/thunderbolt/nhi.h
new file mode 100644
index 0000000..3172429
--- /dev/null
+++ b/drivers/thunderbolt/nhi.h
@@ -0,0 +1,114 @@
+/*
+ * Thunderbolt Cactus Ridge driver - NHI driver
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ */
+
+#ifndef DSL3510_H_
+#define DSL3510_H_
+
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+
+/**
+ * struct tb_nhi - thunderbolt native host interface
+ */
+struct tb_nhi {
+	struct mutex lock; /*
+			    * Must be held during ring creation/destruction.
+			    * Is acquired by interrupt_work when dispatching
+			    * interrupts to individual rings.
+			    **/
+	struct pci_dev *pdev;
+	void __iomem *iobase;
+	struct tb_ring **tx_rings;
+	struct tb_ring **rx_rings;
+	struct work_struct interrupt_work;
+	u32 hop_count; /* Number of rings (end point hops) supported by NHI. */
+};
+
+/**
+ * struct tb_ring - thunderbolt TX or RX ring associated with a NHI
+ */
+struct tb_ring {
+	struct mutex lock; /* must be acquired after nhi->lock */
+	struct tb_nhi *nhi;
+	int size;
+	int hop;
+	int head; /* write next descriptor here */
+	int tail; /* complete next descriptor here */
+	struct ring_desc *descriptors;
+	dma_addr_t descriptors_dma;
+	struct list_head queue;
+	struct list_head in_flight;
+	struct work_struct work;
+	bool is_tx:1; /* rx otherwise */
+	bool running:1;
+};
+
+struct ring_frame;
+typedef void (*ring_cb)(struct tb_ring*, struct ring_frame*, bool canceled);
+
+/**
+ * struct ring_frame - for use with ring_rx/ring_tx
+ */
+struct ring_frame {
+	dma_addr_t buffer_phy;
+	ring_cb callback;
+	struct list_head list;
+	u32 size:12; /* TX: in, RX: out*/
+	u32 flags:12; /* RX: out */
+	u32 eof:4; /* TX:in, RX: out */
+	u32 sof:4; /* TX:in, RX: out */
+};
+
+#define TB_FRAME_SIZE 0x100    /* minimum size for ring_rx */
+
+struct tb_ring *ring_alloc_tx(struct tb_nhi *nhi, int hop, int size);
+struct tb_ring *ring_alloc_rx(struct tb_nhi *nhi, int hop, int size);
+void ring_start(struct tb_ring *ring);
+void ring_stop(struct tb_ring *ring);
+void ring_free(struct tb_ring *ring);
+
+int __ring_enqueue(struct tb_ring *ring, struct ring_frame *frame);
+
+/**
+ * ring_rx() - enqueue a frame on an RX ring
+ *
+ * frame->buffer, frame->buffer_phy and frame->callback have to be set. The
+ * buffer must contain at least TB_FRAME_SIZE bytes.
+ *
+ * frame->callback will be invoked with frame->size, frame->flags, frame->eof,
+ * frame->sof set once the frame has been received.
+ *
+ * If ring_stop is called after the packet has been enqueued frame->callback
+ * will be called with canceled set to true.
+ *
+ * Return: Returns ESHUTDOWN if ring_stop has been called. Zero otherwise.
+ */
+static inline int ring_rx(struct tb_ring *ring, struct ring_frame *frame)
+{
+	WARN_ON(ring->is_tx);
+	return __ring_enqueue(ring, frame);
+}
+
+/**
+ * ring_tx() - enqueue a frame on an TX ring
+ *
+ * frame->buffer, frame->buffer_phy, frame->callback, frame->size, frame->eof
+ * and frame->sof have to be set.
+ *
+ * frame->callback will be invoked with once the frame has been transmitted.
+ *
+ * If ring_stop is called after the packet has been enqueued frame->callback
+ * will be called with canceled set to true.
+ *
+ * Return: Returns ESHUTDOWN if ring_stop has been called. Zero otherwise.
+ */
+static inline int ring_tx(struct tb_ring *ring, struct ring_frame *frame)
+{
+	WARN_ON(!ring->is_tx);
+	return __ring_enqueue(ring, frame);
+}
+
+#endif
diff --git a/drivers/thunderbolt/nhi_regs.h b/drivers/thunderbolt/nhi_regs.h
new file mode 100644
index 0000000..86b996c
--- /dev/null
+++ b/drivers/thunderbolt/nhi_regs.h
@@ -0,0 +1,101 @@
+/*
+ * Thunderbolt Cactus Ridge driver - NHI registers
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ */
+
+#ifndef DSL3510_REGS_H_
+#define DSL3510_REGS_H_
+
+#include <linux/types.h>
+
+enum ring_flags {
+	RING_FLAG_ISOCH_ENABLE = 1 << 27, /* TX only? */
+	RING_FLAG_E2E_FLOW_CONTROL = 1 << 28,
+	RING_FLAG_PCI_NO_SNOOP = 1 << 29,
+	RING_FLAG_RAW = 1 << 30, /* ignore EOF/SOF mask, include checksum */
+	RING_FLAG_ENABLE = 1 << 31,
+};
+
+enum ring_desc_flags {
+	RING_DESC_ISOCH = 0x1, /* TX only? */
+	RING_DESC_COMPLETED = 0x2, /* set by NHI */
+	RING_DESC_POSTED = 0x4, /* always set this */
+	RING_DESC_INTERRUPT = 0x8, /* request an interrupt on completion */
+};
+
+/**
+ * struct ring_desc - TX/RX ring entry
+ *
+ * For TX set length/eof/sof.
+ * For RX length/eof/sof are set by the NHI.
+ */
+struct ring_desc {
+	u64 phys;
+	u32 length:12;
+	u32 eof:4;
+	u32 sof:4;
+	enum ring_desc_flags flags:12;
+	u32 time; /* write zero */
+} __packed;
+
+/* NHI registers in bar 0 */
+
+/*
+ * 16 bytes per entry, one entry for every hop (REG_HOP_COUNT)
+ * 00: physical pointer to an array of struct ring_desc
+ * 08: ring tail (set by NHI)
+ * 10: ring head (index of first non posted descriptor)
+ * 12: descriptor count
+ */
+#define REG_TX_RING_BASE	0x00000
+
+/*
+ * 16 bytes per entry, one entry for every hop (REG_HOP_COUNT)
+ * 00: physical pointer to an array of struct ring_desc
+ * 08: ring head (index of first not posted descriptor)
+ * 10: ring tail (set by NHI)
+ * 12: descriptor count
+ * 14: max frame sizes (anything larger than 0x100 has no effect)
+ */
+#define REG_RX_RING_BASE	0x08000
+
+/*
+ * 32 bytes per entry, one entry for every hop (REG_HOP_COUNT)
+ * 00: enum_ring_flags
+ * 04: isoch time stamp ?? (write 0)
+ * ..: unknown
+ */
+#define REG_TX_OPTIONS_BASE	0x19800
+
+/*
+ * 32 bytes per entry, one entry for every hop (REG_HOP_COUNT)
+ * 00: enum ring_flags
+ *     If RING_FLAG_E2E_FLOW_CONTROL is set then bits 13-23 must be set to
+ *     the corresponding TX hop id.
+ * 04: EOF/SOF mask (ignored for RING_FLAG_RAW rings)
+ * ..: unknown
+ */
+#define REG_RX_OPTIONS_BASE	0x29800
+
+/*
+ * three bitfields: tx, rx, rx overflow
+ * Every bitfield contains one bit for every hop (REG_HOP_COUNT). Registers are
+ * cleared on read. New interrupts are fired only after ALL registers have been
+ * read (even those containing only disabled rings).
+ */
+#define REG_RING_NOTIFY_BASE	0x37800
+#define RING_NOTIFY_REG_COUNT(nhi) ((31 + 3 * nhi->hop_count) / 32)
+
+/*
+ * two bitfields: rx, tx
+ * Both bitfields contains one bit for every hop (REG_HOP_COUNT). To
+ * enable/disable interrupts set/clear the corresponding bits.
+ */
+#define REG_RING_INTERRUPT_BASE	0x38200
+#define RING_INTERRUPT_REG_COUNT(nhi) ((31 + 2 * nhi->hop_count) / 32)
+
+/* The last 11 bits contain the number of hops supported by the NHI port. */
+#define REG_HOP_COUNT		0x39640
+
+#endif