thunderbolt: Add support for Internal Connection Manager (ICM)

Starting from Intel Falcon Ridge the internal connection manager running
on the Thunderbolt host controller has been supporting 4 security
levels. One reason for this is to prevent DMA attacks and only allow
connecting devices the user trusts.

The internal connection manager (ICM) is the preferred way of connecting
Thunderbolt devices over software only implementation typically used on
Macs. The driver communicates with ICM using special Thunderbolt ring 0
(control channel) messages. In order to handle these messages we add
support for the ICM messages to the control channel.

The security levels are as follows:

  none - No security, all tunnels are created automatically
  user - User needs to approve the device before tunnels are created
  secure - User need to approve the device before tunnels are created.
	   The device is sent a challenge on future connects to be able
	   to verify it is actually the approved device.
  dponly - Only Display Port and USB tunnels can be created and those
           are created automatically.

The security levels are typically configurable from the system BIOS and
by default it is set to "user" on many systems.

In this patch each Thunderbolt device will have either one or two new
sysfs attributes: authorized and key. The latter appears for devices
that support secure connect.

In order to identify the device the user can read identication
information, including UUID and name of the device from sysfs and based
on that make a decision to authorize the device. The device is
authorized by simply writing 1 to the "authorized" sysfs attribute. This
is following the USB bus device authorization mechanism. The secure
connect requires an additional challenge step (writing 2 to the
"authorized" attribute) in future connects when the key has already been
stored to the NVM of the device.

Non-ICM systems (before Alpine Ridge) continue to use the existing
functionality and the security level is set to none. For systems with
Alpine Ridge, even on Apple hardware, we will use ICM.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1058 insertions, 0 deletions

diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
new file mode 100644
index 000000000000..0ffa4ec249ac
--- /dev/null
+++ b/drivers/thunderbolt/icm.c
@@ -0,0 +1,1058 @@
+/*
+ * Internal Thunderbolt Connection Manager. This is a firmware running on
+ * the Thunderbolt host controller performing most of the low-level
+ * handling.
+ *
+ * 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/delay.h>
+#include <linux/dmi.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "ctl.h"
+#include "nhi_regs.h"
+#include "tb.h"
+
+#define PCIE2CIO_CMD			0x30
+#define PCIE2CIO_CMD_TIMEOUT		BIT(31)
+#define PCIE2CIO_CMD_START		BIT(30)
+#define PCIE2CIO_CMD_WRITE		BIT(21)
+#define PCIE2CIO_CMD_CS_MASK		GENMASK(20, 19)
+#define PCIE2CIO_CMD_CS_SHIFT		19
+#define PCIE2CIO_CMD_PORT_MASK		GENMASK(18, 13)
+#define PCIE2CIO_CMD_PORT_SHIFT		13
+
+#define PCIE2CIO_WRDATA			0x34
+#define PCIE2CIO_RDDATA			0x38
+
+#define PHY_PORT_CS1			0x37
+#define PHY_PORT_CS1_LINK_DISABLE	BIT(14)
+#define PHY_PORT_CS1_LINK_STATE_MASK	GENMASK(29, 26)
+#define PHY_PORT_CS1_LINK_STATE_SHIFT	26
+
+#define ICM_TIMEOUT			5000 /* ms */
+#define ICM_MAX_LINK			4
+#define ICM_MAX_DEPTH			6
+
+/**
+ * struct icm - Internal connection manager private data
+ * @request_lock: Makes sure only one message is send to ICM at time
+ * @rescan_work: Work used to rescan the surviving switches after resume
+ * @upstream_port: Pointer to the PCIe upstream port this host
+ *		   controller is connected. This is only set for systems
+ *		   where ICM needs to be started manually
+ * @vnd_cap: Vendor defined capability where PCIe2CIO mailbox resides
+ *	     (only set when @upstream_port is not %NULL)
+ * @is_supported: Checks if we can support ICM on this controller
+ * @get_mode: Read and return the ICM firmware mode (optional)
+ * @get_route: Find a route string for given switch
+ * @device_connected: Handle device connected ICM message
+ * @device_disconnected: Handle device disconnected ICM message
+ */
+struct icm {
+	struct mutex request_lock;
+	struct delayed_work rescan_work;
+	struct pci_dev *upstream_port;
+	int vnd_cap;
+	bool (*is_supported)(struct tb *tb);
+	int (*get_mode)(struct tb *tb);
+	int (*get_route)(struct tb *tb, u8 link, u8 depth, u64 *route);
+	void (*device_connected)(struct tb *tb,
+				 const struct icm_pkg_header *hdr);
+	void (*device_disconnected)(struct tb *tb,
+				    const struct icm_pkg_header *hdr);
+};
+
+struct icm_notification {
+	struct work_struct work;
+	struct icm_pkg_header *pkg;
+	struct tb *tb;
+};
+
+static inline struct tb *icm_to_tb(struct icm *icm)
+{
+	return ((void *)icm - sizeof(struct tb));
+}
+
+static inline u8 phy_port_from_route(u64 route, u8 depth)
+{
+	return tb_switch_phy_port_from_link(route >> ((depth - 1) * 8));
+}
+
+static inline u8 dual_link_from_link(u8 link)
+{
+	return link ? ((link - 1) ^ 0x01) + 1 : 0;
+}
+
+static inline u64 get_route(u32 route_hi, u32 route_lo)
+{
+	return (u64)route_hi << 32 | route_lo;
+}
+
+static inline bool is_apple(void)
+{
+	return dmi_match(DMI_BOARD_VENDOR, "Apple Inc.");
+}
+
+static bool icm_match(const struct tb_cfg_request *req,
+		      const struct ctl_pkg *pkg)
+{
+	const struct icm_pkg_header *res_hdr = pkg->buffer;
+	const struct icm_pkg_header *req_hdr = req->request;
+
+	if (pkg->frame.eof != req->response_type)
+		return false;
+	if (res_hdr->code != req_hdr->code)
+		return false;
+
+	return true;
+}
+
+static bool icm_copy(struct tb_cfg_request *req, const struct ctl_pkg *pkg)
+{
+	const struct icm_pkg_header *hdr = pkg->buffer;
+
+	if (hdr->packet_id < req->npackets) {
+		size_t offset = hdr->packet_id * req->response_size;
+
+		memcpy(req->response + offset, pkg->buffer, req->response_size);
+	}
+
+	return hdr->packet_id == hdr->total_packets - 1;
+}
+
+static int icm_request(struct tb *tb, const void *request, size_t request_size,
+		       void *response, size_t response_size, size_t npackets,
+		       unsigned int timeout_msec)
+{
+	struct icm *icm = tb_priv(tb);
+	int retries = 3;
+
+	do {
+		struct tb_cfg_request *req;
+		struct tb_cfg_result res;
+
+		req = tb_cfg_request_alloc();
+		if (!req)
+			return -ENOMEM;
+
+		req->match = icm_match;
+		req->copy = icm_copy;
+		req->request = request;
+		req->request_size = request_size;
+		req->request_type = TB_CFG_PKG_ICM_CMD;
+		req->response = response;
+		req->npackets = npackets;
+		req->response_size = response_size;
+		req->response_type = TB_CFG_PKG_ICM_RESP;
+
+		mutex_lock(&icm->request_lock);
+		res = tb_cfg_request_sync(tb->ctl, req, timeout_msec);
+		mutex_unlock(&icm->request_lock);
+
+		tb_cfg_request_put(req);
+
+		if (res.err != -ETIMEDOUT)
+			return res.err == 1 ? -EIO : res.err;
+
+		usleep_range(20, 50);
+	} while (retries--);
+
+	return -ETIMEDOUT;
+}
+
+static bool icm_fr_is_supported(struct tb *tb)
+{
+	return !is_apple();
+}
+
+static inline int icm_fr_get_switch_index(u32 port)
+{
+	int index;
+
+	if ((port & ICM_PORT_TYPE_MASK) != TB_TYPE_PORT)
+		return 0;
+
+	index = port >> ICM_PORT_INDEX_SHIFT;
+	return index != 0xff ? index : 0;
+}
+
+static int icm_fr_get_route(struct tb *tb, u8 link, u8 depth, u64 *route)
+{
+	struct icm_fr_pkg_get_topology_response *switches, *sw;
+	struct icm_fr_pkg_get_topology request = {
+		.hdr = { .code = ICM_GET_TOPOLOGY },
+	};
+	size_t npackets = ICM_GET_TOPOLOGY_PACKETS;
+	int ret, index;
+	u8 i;
+
+	switches = kcalloc(npackets, sizeof(*switches), GFP_KERNEL);
+	if (!switches)
+		return -ENOMEM;
+
+	ret = icm_request(tb, &request, sizeof(request), switches,
+			  sizeof(*switches), npackets, ICM_TIMEOUT);
+	if (ret)
+		goto err_free;
+
+	sw = &switches[0];
+	index = icm_fr_get_switch_index(sw->ports[link]);
+	if (!index) {
+		ret = -ENODEV;
+		goto err_free;
+	}
+
+	sw = &switches[index];
+	for (i = 1; i < depth; i++) {
+		unsigned int j;
+
+		if (!(sw->first_data & ICM_SWITCH_USED)) {
+			ret = -ENODEV;
+			goto err_free;
+		}
+
+		for (j = 0; j < ARRAY_SIZE(sw->ports); j++) {
+			index = icm_fr_get_switch_index(sw->ports[j]);
+			if (index > sw->switch_index) {
+				sw = &switches[index];
+				break;
+			}
+		}
+	}
+
+	*route = get_route(sw->route_hi, sw->route_lo);
+
+err_free:
+	kfree(switches);
+	return ret;
+}
+
+static int icm_fr_approve_switch(struct tb *tb, struct tb_switch *sw)
+{
+	struct icm_fr_pkg_approve_device request;
+	struct icm_fr_pkg_approve_device reply;
+	int ret;
+
+	memset(&request, 0, sizeof(request));
+	memcpy(&request.ep_uuid, sw->uuid, sizeof(request.ep_uuid));
+	request.hdr.code = ICM_APPROVE_DEVICE;
+	request.connection_id = sw->connection_id;
+	request.connection_key = sw->connection_key;
+
+	memset(&reply, 0, sizeof(reply));
+	/* Use larger timeout as establishing tunnels can take some time */
+	ret = icm_request(tb, &request, sizeof(request), &reply, sizeof(reply),
+			  1, 10000);
+	if (ret)
+		return ret;
+
+	if (reply.hdr.flags & ICM_FLAGS_ERROR) {
+		tb_warn(tb, "PCIe tunnel creation failed\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int icm_fr_add_switch_key(struct tb *tb, struct tb_switch *sw)
+{
+	struct icm_fr_pkg_add_device_key request;
+	struct icm_fr_pkg_add_device_key_response reply;
+	int ret;
+
+	memset(&request, 0, sizeof(request));
+	memcpy(&request.ep_uuid, sw->uuid, sizeof(request.ep_uuid));
+	request.hdr.code = ICM_ADD_DEVICE_KEY;
+	request.connection_id = sw->connection_id;
+	request.connection_key = sw->connection_key;
+	memcpy(request.key, sw->key, TB_SWITCH_KEY_SIZE);
+
+	memset(&reply, 0, sizeof(reply));
+	ret = icm_request(tb, &request, sizeof(request), &reply, sizeof(reply),
+			  1, ICM_TIMEOUT);
+	if (ret)
+		return ret;
+
+	if (reply.hdr.flags & ICM_FLAGS_ERROR) {
+		tb_warn(tb, "Adding key to switch failed\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int icm_fr_challenge_switch_key(struct tb *tb, struct tb_switch *sw,
+				       const u8 *challenge, u8 *response)
+{
+	struct icm_fr_pkg_challenge_device request;
+	struct icm_fr_pkg_challenge_device_response reply;
+	int ret;
+
+	memset(&request, 0, sizeof(request));
+	memcpy(&request.ep_uuid, sw->uuid, sizeof(request.ep_uuid));
+	request.hdr.code = ICM_CHALLENGE_DEVICE;
+	request.connection_id = sw->connection_id;
+	request.connection_key = sw->connection_key;
+	memcpy(request.challenge, challenge, TB_SWITCH_KEY_SIZE);
+
+	memset(&reply, 0, sizeof(reply));
+	ret = icm_request(tb, &request, sizeof(request), &reply, sizeof(reply),
+			  1, ICM_TIMEOUT);
+	if (ret)
+		return ret;
+
+	if (reply.hdr.flags & ICM_FLAGS_ERROR)
+		return -EKEYREJECTED;
+	if (reply.hdr.flags & ICM_FLAGS_NO_KEY)
+		return -ENOKEY;
+
+	memcpy(response, reply.response, TB_SWITCH_KEY_SIZE);
+
+	return 0;
+}
+
+static void remove_switch(struct tb_switch *sw)
+{
+	struct tb_switch *parent_sw;
+
+	parent_sw = tb_to_switch(sw->dev.parent);
+	tb_port_at(tb_route(sw), parent_sw)->remote = NULL;
+	tb_switch_remove(sw);
+}
+
+static void
+icm_fr_device_connected(struct tb *tb, const struct icm_pkg_header *hdr)
+{
+	const struct icm_fr_event_device_connected *pkg =
+		(const struct icm_fr_event_device_connected *)hdr;
+	struct tb_switch *sw, *parent_sw;
+	struct icm *icm = tb_priv(tb);
+	bool authorized = false;
+	u8 link, depth;
+	u64 route;
+	int ret;
+
+	link = pkg->link_info & ICM_LINK_INFO_LINK_MASK;
+	depth = (pkg->link_info & ICM_LINK_INFO_DEPTH_MASK) >>
+		ICM_LINK_INFO_DEPTH_SHIFT;
+	authorized = pkg->link_info & ICM_LINK_INFO_APPROVED;
+
+	ret = icm->get_route(tb, link, depth, &route);
+	if (ret) {
+		tb_err(tb, "failed to find route string for switch at %u.%u\n",
+		       link, depth);
+		return;
+	}
+
+	sw = tb_switch_find_by_uuid(tb, &pkg->ep_uuid);
+	if (sw) {
+		u8 phy_port, sw_phy_port;
+
+		parent_sw = tb_to_switch(sw->dev.parent);
+		sw_phy_port = phy_port_from_route(tb_route(sw), sw->depth);
+		phy_port = phy_port_from_route(route, depth);
+
+		/*
+		 * On resume ICM will send us connected events for the
+		 * devices that still are present. However, that
+		 * information might have changed for example by the
+		 * fact that a switch on a dual-link connection might
+		 * have been enumerated using the other link now. Make
+		 * sure our book keeping matches that.
+		 */
+		if (sw->depth == depth && sw_phy_port == phy_port &&
+		    !!sw->authorized == authorized) {
+			tb_port_at(tb_route(sw), parent_sw)->remote = NULL;
+			tb_port_at(route, parent_sw)->remote =
+				   tb_upstream_port(sw);
+			sw->config.route_hi = upper_32_bits(route);
+			sw->config.route_lo = lower_32_bits(route);
+			sw->connection_id = pkg->connection_id;
+			sw->connection_key = pkg->connection_key;
+			sw->link = link;
+			sw->depth = depth;
+			sw->is_unplugged = false;
+			tb_switch_put(sw);
+			return;
+		}
+
+		/*
+		 * User connected the same switch to another physical
+		 * port or to another part of the topology. Remove the
+		 * existing switch now before adding the new one.
+		 */
+		remove_switch(sw);
+		tb_switch_put(sw);
+	}
+
+	/*
+	 * If the switch was not found by UUID, look for a switch on
+	 * same physical port (taking possible link aggregation into
+	 * account) and depth. If we found one it is definitely a stale
+	 * one so remove it first.
+	 */
+	sw = tb_switch_find_by_link_depth(tb, link, depth);
+	if (!sw) {
+		u8 dual_link;
+
+		dual_link = dual_link_from_link(link);
+		if (dual_link)
+			sw = tb_switch_find_by_link_depth(tb, dual_link, depth);
+	}
+	if (sw) {
+		remove_switch(sw);
+		tb_switch_put(sw);
+	}
+
+	parent_sw = tb_switch_find_by_link_depth(tb, link, depth - 1);
+	if (!parent_sw) {
+		tb_err(tb, "failed to find parent switch for %u.%u\n",
+		       link, depth);
+		return;
+	}
+
+	sw = tb_switch_alloc(tb, &parent_sw->dev, route);
+	if (!sw) {
+		tb_switch_put(parent_sw);
+		return;
+	}
+
+	sw->uuid = kmemdup(&pkg->ep_uuid, sizeof(pkg->ep_uuid), GFP_KERNEL);
+	sw->connection_id = pkg->connection_id;
+	sw->connection_key = pkg->connection_key;
+	sw->link = link;
+	sw->depth = depth;
+	sw->authorized = authorized;
+	sw->security_level = (pkg->hdr.flags & ICM_FLAGS_SLEVEL_MASK) >>
+				ICM_FLAGS_SLEVEL_SHIFT;
+
+	/* Link the two switches now */
+	tb_port_at(route, parent_sw)->remote = tb_upstream_port(sw);
+	tb_upstream_port(sw)->remote = tb_port_at(route, parent_sw);
+
+	ret = tb_switch_add(sw);
+	if (ret) {
+		tb_port_at(tb_route(sw), parent_sw)->remote = NULL;
+		tb_switch_put(sw);
+	}
+	tb_switch_put(parent_sw);
+}
+
+static void
+icm_fr_device_disconnected(struct tb *tb, const struct icm_pkg_header *hdr)
+{
+	const struct icm_fr_event_device_disconnected *pkg =
+		(const struct icm_fr_event_device_disconnected *)hdr;
+	struct tb_switch *sw;
+	u8 link, depth;
+
+	link = pkg->link_info & ICM_LINK_INFO_LINK_MASK;
+	depth = (pkg->link_info & ICM_LINK_INFO_DEPTH_MASK) >>
+		ICM_LINK_INFO_DEPTH_SHIFT;
+
+	if (link > ICM_MAX_LINK || depth > ICM_MAX_DEPTH) {
+		tb_warn(tb, "invalid topology %u.%u, ignoring\n", link, depth);
+		return;
+	}
+
+	sw = tb_switch_find_by_link_depth(tb, link, depth);
+	if (!sw) {
+		tb_warn(tb, "no switch exists at %u.%u, ignoring\n", link,
+			depth);
+		return;
+	}
+
+	remove_switch(sw);
+	tb_switch_put(sw);
+}
+
+static struct pci_dev *get_upstream_port(struct pci_dev *pdev)
+{
+	struct pci_dev *parent;
+
+	parent = pci_upstream_bridge(pdev);
+	while (parent) {
+		if (!pci_is_pcie(parent))
+			return NULL;
+		if (pci_pcie_type(parent) == PCI_EXP_TYPE_UPSTREAM)
+			break;
+		parent = pci_upstream_bridge(parent);
+	}
+
+	if (!parent)
+		return NULL;
+
+	switch (parent->device) {
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_BRIDGE:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_BRIDGE:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_BRIDGE:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_BRIDGE:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_BRIDGE:
+		return parent;
+	}
+
+	return NULL;
+}
+
+static bool icm_ar_is_supported(struct tb *tb)
+{
+	struct pci_dev *upstream_port;
+	struct icm *icm = tb_priv(tb);
+
+	/*
+	 * Starting from Alpine Ridge we can use ICM on Apple machines
+	 * as well. We just need to reset and re-enable it first.
+	 */
+	if (!is_apple())
+		return true;
+
+	/*
+	 * Find the upstream PCIe port in case we need to do reset
+	 * through its vendor specific registers.
+	 */
+	upstream_port = get_upstream_port(tb->nhi->pdev);
+	if (upstream_port) {
+		int cap;
+
+		cap = pci_find_ext_capability(upstream_port,
+					      PCI_EXT_CAP_ID_VNDR);
+		if (cap > 0) {
+			icm->upstream_port = upstream_port;
+			icm->vnd_cap = cap;
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static int icm_ar_get_mode(struct tb *tb)
+{
+	struct tb_nhi *nhi = tb->nhi;
+	int retries = 5;
+	u32 val;
+
+	do {
+		val = ioread32(nhi->iobase + REG_FW_STS);
+		if (val & REG_FW_STS_NVM_AUTH_DONE)
+			break;
+		msleep(30);
+	} while (--retries);
+
+	if (!retries) {
+		dev_err(&nhi->pdev->dev, "ICM firmware not authenticated\n");
+		return -ENODEV;
+	}
+
+	return nhi_mailbox_mode(nhi);
+}
+
+static int icm_ar_get_route(struct tb *tb, u8 link, u8 depth, u64 *route)
+{
+	struct icm_ar_pkg_get_route_response reply;
+	struct icm_ar_pkg_get_route request = {
+		.hdr = { .code = ICM_GET_ROUTE },
+		.link_info = depth << ICM_LINK_INFO_DEPTH_SHIFT | link,
+	};
+	int ret;
+
+	memset(&reply, 0, sizeof(reply));
+	ret = icm_request(tb, &request, sizeof(request), &reply, sizeof(reply),
+			  1, ICM_TIMEOUT);
+	if (ret)
+		return ret;
+
+	if (reply.hdr.flags & ICM_FLAGS_ERROR)
+		return -EIO;
+
+	*route = get_route(reply.route_hi, reply.route_lo);
+	return 0;
+}
+
+static void icm_handle_notification(struct work_struct *work)
+{
+	struct icm_notification *n = container_of(work, typeof(*n), work);
+	struct tb *tb = n->tb;
+	struct icm *icm = tb_priv(tb);
+
+	mutex_lock(&tb->lock);
+
+	switch (n->pkg->code) {
+	case ICM_EVENT_DEVICE_CONNECTED:
+		icm->device_connected(tb, n->pkg);
+		break;
+	case ICM_EVENT_DEVICE_DISCONNECTED:
+		icm->device_disconnected(tb, n->pkg);
+		break;
+	}
+
+	mutex_unlock(&tb->lock);
+
+	kfree(n->pkg);
+	kfree(n);
+}
+
+static void icm_handle_event(struct tb *tb, enum tb_cfg_pkg_type type,
+			     const void *buf, size_t size)
+{
+	struct icm_notification *n;
+
+	n = kmalloc(sizeof(*n), GFP_KERNEL);
+	if (!n)
+		return;
+
+	INIT_WORK(&n->work, icm_handle_notification);
+	n->pkg = kmemdup(buf, size, GFP_KERNEL);
+	n->tb = tb;
+
+	queue_work(tb->wq, &n->work);
+}
+
+static int
+__icm_driver_ready(struct tb *tb, enum tb_security_level *security_level)
+{
+	struct icm_pkg_driver_ready_response reply;
+	struct icm_pkg_driver_ready request = {
+		.hdr.code = ICM_DRIVER_READY,
+	};
+	unsigned int retries = 10;
+	int ret;
+
+	memset(&reply, 0, sizeof(reply));
+	ret = icm_request(tb, &request, sizeof(request), &reply, sizeof(reply),
+			  1, ICM_TIMEOUT);
+	if (ret)
+		return ret;
+
+	if (security_level)
+		*security_level = reply.security_level & 0xf;
+
+	/*
+	 * Hold on here until the switch config space is accessible so
+	 * that we can read root switch config successfully.
+	 */
+	do {
+		struct tb_cfg_result res;
+		u32 tmp;
+
+		res = tb_cfg_read_raw(tb->ctl, &tmp, 0, 0, TB_CFG_SWITCH,
+				      0, 1, 100);
+		if (!res.err)
+			return 0;
+
+		msleep(50);
+	} while (--retries);
+
+	return -ETIMEDOUT;
+}
+
+static int pci2cio_wait_completion(struct icm *icm, unsigned long timeout_msec)
+{
+	unsigned long end = jiffies + msecs_to_jiffies(timeout_msec);
+	u32 cmd;
+
+	do {
+		pci_read_config_dword(icm->upstream_port,
+				      icm->vnd_cap + PCIE2CIO_CMD, &cmd);
+		if (!(cmd & PCIE2CIO_CMD_START)) {
+			if (cmd & PCIE2CIO_CMD_TIMEOUT)
+				break;
+			return 0;
+		}
+
+		msleep(50);
+	} while (time_before(jiffies, end));
+
+	return -ETIMEDOUT;
+}
+
+static int pcie2cio_read(struct icm *icm, enum tb_cfg_space cs,
+			 unsigned int port, unsigned int index, u32 *data)
+{
+	struct pci_dev *pdev = icm->upstream_port;
+	int ret, vnd_cap = icm->vnd_cap;
+	u32 cmd;
+
+	cmd = index;
+	cmd |= (port << PCIE2CIO_CMD_PORT_SHIFT) & PCIE2CIO_CMD_PORT_MASK;
+	cmd |= (cs << PCIE2CIO_CMD_CS_SHIFT) & PCIE2CIO_CMD_CS_MASK;
+	cmd |= PCIE2CIO_CMD_START;
+	pci_write_config_dword(pdev, vnd_cap + PCIE2CIO_CMD, cmd);
+
+	ret = pci2cio_wait_completion(icm, 5000);
+	if (ret)
+		return ret;
+
+	pci_read_config_dword(pdev, vnd_cap + PCIE2CIO_RDDATA, data);
+	return 0;
+}
+
+static int pcie2cio_write(struct icm *icm, enum tb_cfg_space cs,
+			  unsigned int port, unsigned int index, u32 data)
+{
+	struct pci_dev *pdev = icm->upstream_port;
+	int vnd_cap = icm->vnd_cap;
+	u32 cmd;
+
+	pci_write_config_dword(pdev, vnd_cap + PCIE2CIO_WRDATA, data);
+
+	cmd = index;
+	cmd |= (port << PCIE2CIO_CMD_PORT_SHIFT) & PCIE2CIO_CMD_PORT_MASK;
+	cmd |= (cs << PCIE2CIO_CMD_CS_SHIFT) & PCIE2CIO_CMD_CS_MASK;
+	cmd |= PCIE2CIO_CMD_WRITE | PCIE2CIO_CMD_START;
+	pci_write_config_dword(pdev, vnd_cap + PCIE2CIO_CMD, cmd);
+
+	return pci2cio_wait_completion(icm, 5000);
+}
+
+static int icm_firmware_reset(struct tb *tb, struct tb_nhi *nhi)
+{
+	struct icm *icm = tb_priv(tb);
+	u32 val;
+
+	/* Put ARC to wait for CIO reset event to happen */
+	val = ioread32(nhi->iobase + REG_FW_STS);
+	val |= REG_FW_STS_CIO_RESET_REQ;
+	iowrite32(val, nhi->iobase + REG_FW_STS);
+
+	/* Re-start ARC */
+	val = ioread32(nhi->iobase + REG_FW_STS);
+	val |= REG_FW_STS_ICM_EN_INVERT;
+	val |= REG_FW_STS_ICM_EN_CPU;
+	iowrite32(val, nhi->iobase + REG_FW_STS);
+
+	/* Trigger CIO reset now */
+	return pcie2cio_write(icm, TB_CFG_SWITCH, 0, 0x50, BIT(9));
+}
+
+static int icm_firmware_start(struct tb *tb, struct tb_nhi *nhi)
+{
+	unsigned int retries = 10;
+	int ret;
+	u32 val;
+
+	/* Check if the ICM firmware is already running */
+	val = ioread32(nhi->iobase + REG_FW_STS);
+	if (val & REG_FW_STS_ICM_EN)
+		return 0;
+
+	dev_info(&nhi->pdev->dev, "starting ICM firmware\n");
+
+	ret = icm_firmware_reset(tb, nhi);
+	if (ret)
+		return ret;
+
+	/* Wait until the ICM firmware tells us it is up and running */
+	do {
+		/* Check that the ICM firmware is running */
+		val = ioread32(nhi->iobase + REG_FW_STS);
+		if (val & REG_FW_STS_NVM_AUTH_DONE)
+			return 0;
+
+		msleep(300);
+	} while (--retries);
+
+	return -ETIMEDOUT;
+}
+
+static int icm_reset_phy_port(struct tb *tb, int phy_port)
+{
+	struct icm *icm = tb_priv(tb);
+	u32 state0, state1;
+	int port0, port1;
+	u32 val0, val1;
+	int ret;
+
+	if (!icm->upstream_port)
+		return 0;
+
+	if (phy_port) {
+		port0 = 3;
+		port1 = 4;
+	} else {
+		port0 = 1;
+		port1 = 2;
+	}
+
+	/*
+	 * Read link status of both null ports belonging to a single
+	 * physical port.
+	 */
+	ret = pcie2cio_read(icm, TB_CFG_PORT, port0, PHY_PORT_CS1, &val0);
+	if (ret)
+		return ret;
+	ret = pcie2cio_read(icm, TB_CFG_PORT, port1, PHY_PORT_CS1, &val1);
+	if (ret)
+		return ret;
+
+	state0 = val0 & PHY_PORT_CS1_LINK_STATE_MASK;
+	state0 >>= PHY_PORT_CS1_LINK_STATE_SHIFT;
+	state1 = val1 & PHY_PORT_CS1_LINK_STATE_MASK;
+	state1 >>= PHY_PORT_CS1_LINK_STATE_SHIFT;
+
+	/* If they are both up we need to reset them now */
+	if (state0 != TB_PORT_UP || state1 != TB_PORT_UP)
+		return 0;
+
+	val0 |= PHY_PORT_CS1_LINK_DISABLE;
+	ret = pcie2cio_write(icm, TB_CFG_PORT, port0, PHY_PORT_CS1, val0);
+	if (ret)
+		return ret;
+
+	val1 |= PHY_PORT_CS1_LINK_DISABLE;
+	ret = pcie2cio_write(icm, TB_CFG_PORT, port1, PHY_PORT_CS1, val1);
+	if (ret)
+		return ret;
+
+	/* Wait a bit and then re-enable both ports */
+	usleep_range(10, 100);
+
+	ret = pcie2cio_read(icm, TB_CFG_PORT, port0, PHY_PORT_CS1, &val0);
+	if (ret)
+		return ret;
+	ret = pcie2cio_read(icm, TB_CFG_PORT, port1, PHY_PORT_CS1, &val1);
+	if (ret)
+		return ret;
+
+	val0 &= ~PHY_PORT_CS1_LINK_DISABLE;
+	ret = pcie2cio_write(icm, TB_CFG_PORT, port0, PHY_PORT_CS1, val0);
+	if (ret)
+		return ret;
+
+	val1 &= ~PHY_PORT_CS1_LINK_DISABLE;
+	return pcie2cio_write(icm, TB_CFG_PORT, port1, PHY_PORT_CS1, val1);
+}
+
+static int icm_firmware_init(struct tb *tb)
+{
+	struct icm *icm = tb_priv(tb);
+	struct tb_nhi *nhi = tb->nhi;
+	int ret;
+
+	ret = icm_firmware_start(tb, nhi);
+	if (ret) {
+		dev_err(&nhi->pdev->dev, "could not start ICM firmware\n");
+		return ret;
+	}
+
+	if (icm->get_mode) {
+		ret = icm->get_mode(tb);
+
+		switch (ret) {
+		case NHI_FW_CM_MODE:
+			/* Ask ICM to accept all Thunderbolt devices */
+			nhi_mailbox_cmd(nhi, NHI_MAILBOX_ALLOW_ALL_DEVS, 0);
+			break;
+
+		default:
+			tb_err(tb, "ICM firmware is in wrong mode: %u\n", ret);
+			return -ENODEV;
+		}
+	}
+
+	/*
+	 * Reset both physical ports if there is anything connected to
+	 * them already.
+	 */
+	ret = icm_reset_phy_port(tb, 0);
+	if (ret)
+		dev_warn(&nhi->pdev->dev, "failed to reset links on port0\n");
+	ret = icm_reset_phy_port(tb, 1);
+	if (ret)
+		dev_warn(&nhi->pdev->dev, "failed to reset links on port1\n");
+
+	return 0;
+}
+
+static int icm_driver_ready(struct tb *tb)
+{
+	int ret;
+
+	ret = icm_firmware_init(tb);
+	if (ret)
+		return ret;
+
+	return __icm_driver_ready(tb, &tb->security_level);
+}
+
+static int icm_suspend(struct tb *tb)
+{
+	return nhi_mailbox_cmd(tb->nhi, NHI_MAILBOX_SAVE_DEVS, 0);
+}
+
+/*
+ * Mark all switches (except root switch) below this one unplugged. ICM
+ * firmware will send us an updated list of switches after we have send
+ * it driver ready command. If a switch is not in that list it will be
+ * removed when we perform rescan.
+ */
+static void icm_unplug_children(struct tb_switch *sw)
+{
+	unsigned int i;
+
+	if (tb_route(sw))
+		sw->is_unplugged = true;
+
+	for (i = 1; i <= sw->config.max_port_number; i++) {
+		struct tb_port *port = &sw->ports[i];
+
+		if (tb_is_upstream_port(port))
+			continue;
+		if (!port->remote)
+			continue;
+
+		icm_unplug_children(port->remote->sw);
+	}
+}
+
+static void icm_free_unplugged_children(struct tb_switch *sw)
+{
+	unsigned int i;
+
+	for (i = 1; i <= sw->config.max_port_number; i++) {
+		struct tb_port *port = &sw->ports[i];
+
+		if (tb_is_upstream_port(port))
+			continue;
+		if (!port->remote)
+			continue;
+
+		if (port->remote->sw->is_unplugged) {
+			tb_switch_remove(port->remote->sw);
+			port->remote = NULL;
+		} else {
+			icm_free_unplugged_children(port->remote->sw);
+		}
+	}
+}
+
+static void icm_rescan_work(struct work_struct *work)
+{
+	struct icm *icm = container_of(work, struct icm, rescan_work.work);
+	struct tb *tb = icm_to_tb(icm);
+
+	mutex_lock(&tb->lock);
+	if (tb->root_switch)
+		icm_free_unplugged_children(tb->root_switch);
+	mutex_unlock(&tb->lock);
+}
+
+static void icm_complete(struct tb *tb)
+{
+	struct icm *icm = tb_priv(tb);
+
+	if (tb->nhi->going_away)
+		return;
+
+	icm_unplug_children(tb->root_switch);
+
+	/*
+	 * Now all existing children should be resumed, start events
+	 * from ICM to get updated status.
+	 */
+	__icm_driver_ready(tb, NULL);
+
+	/*
+	 * We do not get notifications of devices that have been
+	 * unplugged during suspend so schedule rescan to clean them up
+	 * if any.
+	 */
+	queue_delayed_work(tb->wq, &icm->rescan_work, msecs_to_jiffies(500));
+}
+
+static int icm_start(struct tb *tb)
+{
+	int ret;
+
+	tb->root_switch = tb_switch_alloc(tb, &tb->dev, 0);
+	if (!tb->root_switch)
+		return -ENODEV;
+
+	ret = tb_switch_add(tb->root_switch);
+	if (ret)
+		tb_switch_put(tb->root_switch);
+
+	return ret;
+}
+
+static void icm_stop(struct tb *tb)
+{
+	struct icm *icm = tb_priv(tb);
+
+	cancel_delayed_work(&icm->rescan_work);
+	tb_switch_remove(tb->root_switch);
+	tb->root_switch = NULL;
+	nhi_mailbox_cmd(tb->nhi, NHI_MAILBOX_DRV_UNLOADS, 0);
+}
+
+/* Falcon Ridge and Alpine Ridge */
+static const struct tb_cm_ops icm_fr_ops = {
+	.driver_ready = icm_driver_ready,
+	.start = icm_start,
+	.stop = icm_stop,
+	.suspend = icm_suspend,
+	.complete = icm_complete,
+	.handle_event = icm_handle_event,
+	.approve_switch = icm_fr_approve_switch,
+	.add_switch_key = icm_fr_add_switch_key,
+	.challenge_switch_key = icm_fr_challenge_switch_key,
+};
+
+struct tb *icm_probe(struct tb_nhi *nhi)
+{
+	struct icm *icm;
+	struct tb *tb;
+
+	tb = tb_domain_alloc(nhi, sizeof(struct icm));
+	if (!tb)
+		return NULL;
+
+	icm = tb_priv(tb);
+	INIT_DELAYED_WORK(&icm->rescan_work, icm_rescan_work);
+	mutex_init(&icm->request_lock);
+
+	switch (nhi->pdev->device) {
+	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_NHI:
+	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_NHI:
+		icm->is_supported = icm_fr_is_supported;
+		icm->get_route = icm_fr_get_route;
+		icm->device_connected = icm_fr_device_connected;
+		icm->device_disconnected = icm_fr_device_disconnected;
+		tb->cm_ops = &icm_fr_ops;
+		break;
+
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_2C_NHI:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_NHI:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_LP_NHI:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_4C_NHI:
+	case PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_C_2C_NHI:
+		icm->is_supported = icm_ar_is_supported;
+		icm->get_mode = icm_ar_get_mode;
+		icm->get_route = icm_ar_get_route;
+		icm->device_connected = icm_fr_device_connected;
+		icm->device_disconnected = icm_fr_device_disconnected;
+		tb->cm_ops = &icm_fr_ops;
+		break;
+	}
+
+	if (!icm->is_supported || !icm->is_supported(tb)) {
+		dev_dbg(&nhi->pdev->dev, "ICM not supported on this controller\n");
+		tb_domain_put(tb);
+		return NULL;
+	}
+
+	return tb;
+}