thunderbolt: Add support for XDomain discovery protocol

When two hosts are connected over a Thunderbolt cable, there is a
protocol they can use to communicate capabilities supported by the host.
The discovery protocol uses automatically configured control channel
(ring 0) and is build on top of request/response transactions using
special XDomain primitives provided by the Thunderbolt base protocol.

The capabilities consists of a root directory block of basic properties
used for identification of the host, and then there can be zero or more
directories each describing a Thunderbolt service and its capabilities.

Once both sides have discovered what is supported the two hosts can
setup high-speed DMA paths and transfer data to the other side using
whatever protocol was agreed based on the properties. The software
protocol used to communicate which DMA paths to enable is service
specific.

This patch adds support for the XDomain discovery protocol to the
Thunderbolt bus. We model each remote host connection as a Linux XDomain
device. For each Thunderbolt service found supported on the XDomain
device, we create Linux Thunderbolt service device which Thunderbolt
service drivers can then bind to based on the protocol identification
information retrieved from the property directory describing the
service.

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: David S. Miller <davem@davemloft.net>

1 files changed, 193 insertions, 4 deletions

diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c
index 9f2dcd48974d..9b90115319ce 100644
--- a/drivers/thunderbolt/domain.c
+++ b/drivers/thunderbolt/domain.c
@@ -20,6 +20,98 @@
 
 static DEFINE_IDA(tb_domain_ida);
 
+static bool match_service_id(const struct tb_service_id *id,
+			     const struct tb_service *svc)
+{
+	if (id->match_flags & TBSVC_MATCH_PROTOCOL_KEY) {
+		if (strcmp(id->protocol_key, svc->key))
+			return false;
+	}
+
+	if (id->match_flags & TBSVC_MATCH_PROTOCOL_ID) {
+		if (id->protocol_id != svc->prtcid)
+			return false;
+	}
+
+	if (id->match_flags & TBSVC_MATCH_PROTOCOL_VERSION) {
+		if (id->protocol_version != svc->prtcvers)
+			return false;
+	}
+
+	if (id->match_flags & TBSVC_MATCH_PROTOCOL_VERSION) {
+		if (id->protocol_revision != svc->prtcrevs)
+			return false;
+	}
+
+	return true;
+}
+
+static const struct tb_service_id *__tb_service_match(struct device *dev,
+						      struct device_driver *drv)
+{
+	struct tb_service_driver *driver;
+	const struct tb_service_id *ids;
+	struct tb_service *svc;
+
+	svc = tb_to_service(dev);
+	if (!svc)
+		return NULL;
+
+	driver = container_of(drv, struct tb_service_driver, driver);
+	if (!driver->id_table)
+		return NULL;
+
+	for (ids = driver->id_table; ids->match_flags != 0; ids++) {
+		if (match_service_id(ids, svc))
+			return ids;
+	}
+
+	return NULL;
+}
+
+static int tb_service_match(struct device *dev, struct device_driver *drv)
+{
+	return !!__tb_service_match(dev, drv);
+}
+
+static int tb_service_probe(struct device *dev)
+{
+	struct tb_service *svc = tb_to_service(dev);
+	struct tb_service_driver *driver;
+	const struct tb_service_id *id;
+
+	driver = container_of(dev->driver, struct tb_service_driver, driver);
+	id = __tb_service_match(dev, &driver->driver);
+
+	return driver->probe(svc, id);
+}
+
+static int tb_service_remove(struct device *dev)
+{
+	struct tb_service *svc = tb_to_service(dev);
+	struct tb_service_driver *driver;
+
+	driver = container_of(dev->driver, struct tb_service_driver, driver);
+	if (driver->remove)
+		driver->remove(svc);
+
+	return 0;
+}
+
+static void tb_service_shutdown(struct device *dev)
+{
+	struct tb_service_driver *driver;
+	struct tb_service *svc;
+
+	svc = tb_to_service(dev);
+	if (!svc || !dev->driver)
+		return;
+
+	driver = container_of(dev->driver, struct tb_service_driver, driver);
+	if (driver->shutdown)
+		driver->shutdown(svc);
+}
+
 static const char * const tb_security_names[] = {
 	[TB_SECURITY_NONE] = "none",
 	[TB_SECURITY_USER] = "user",
@@ -52,6 +144,10 @@ static const struct attribute_group *domain_attr_groups[] = {
 
 struct bus_type tb_bus_type = {
 	.name = "thunderbolt",
+	.match = tb_service_match,
+	.probe = tb_service_probe,
+	.remove = tb_service_remove,
+	.shutdown = tb_service_shutdown,
 };
 
 static void tb_domain_release(struct device *dev)
@@ -128,17 +224,26 @@ err_free:
 	return NULL;
 }
 
-static void tb_domain_event_cb(void *data, enum tb_cfg_pkg_type type,
+static bool tb_domain_event_cb(void *data, enum tb_cfg_pkg_type type,
 			       const void *buf, size_t size)
 {
 	struct tb *tb = data;
 
 	if (!tb->cm_ops->handle_event) {
 		tb_warn(tb, "domain does not have event handler\n");
-		return;
+		return true;
 	}
 
-	tb->cm_ops->handle_event(tb, type, buf, size);
+	switch (type) {
+	case TB_CFG_PKG_XDOMAIN_REQ:
+	case TB_CFG_PKG_XDOMAIN_RESP:
+		return tb_xdomain_handle_request(tb, type, buf, size);
+
+	default:
+		tb->cm_ops->handle_event(tb, type, buf, size);
+	}
+
+	return true;
 }
 
 /**
@@ -443,9 +548,92 @@ int tb_domain_disconnect_pcie_paths(struct tb *tb)
 	return tb->cm_ops->disconnect_pcie_paths(tb);
 }
 
+/**
+ * tb_domain_approve_xdomain_paths() - Enable DMA paths for XDomain
+ * @tb: Domain enabling the DMA paths
+ * @xd: XDomain DMA paths are created to
+ *
+ * Calls connection manager specific method to enable DMA paths to the
+ * XDomain in question.
+ *
+ * Return: 0% in case of success and negative errno otherwise. In
+ * particular returns %-ENOTSUPP if the connection manager
+ * implementation does not support XDomains.
+ */
+int tb_domain_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
+{
+	if (!tb->cm_ops->approve_xdomain_paths)
+		return -ENOTSUPP;
+
+	return tb->cm_ops->approve_xdomain_paths(tb, xd);
+}
+
+/**
+ * tb_domain_disconnect_xdomain_paths() - Disable DMA paths for XDomain
+ * @tb: Domain disabling the DMA paths
+ * @xd: XDomain whose DMA paths are disconnected
+ *
+ * Calls connection manager specific method to disconnect DMA paths to
+ * the XDomain in question.
+ *
+ * Return: 0% in case of success and negative errno otherwise. In
+ * particular returns %-ENOTSUPP if the connection manager
+ * implementation does not support XDomains.
+ */
+int tb_domain_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd)
+{
+	if (!tb->cm_ops->disconnect_xdomain_paths)
+		return -ENOTSUPP;
+
+	return tb->cm_ops->disconnect_xdomain_paths(tb, xd);
+}
+
+static int disconnect_xdomain(struct device *dev, void *data)
+{
+	struct tb_xdomain *xd;
+	struct tb *tb = data;
+	int ret = 0;
+
+	xd = tb_to_xdomain(dev);
+	if (xd && xd->tb == tb)
+		ret = tb_xdomain_disable_paths(xd);
+
+	return ret;
+}
+
+/**
+ * tb_domain_disconnect_all_paths() - Disconnect all paths for the domain
+ * @tb: Domain whose paths are disconnected
+ *
+ * This function can be used to disconnect all paths (PCIe, XDomain) for
+ * example in preparation for host NVM firmware upgrade. After this is
+ * called the paths cannot be established without resetting the switch.
+ *
+ * Return: %0 in case of success and negative errno otherwise.
+ */
+int tb_domain_disconnect_all_paths(struct tb *tb)
+{
+	int ret;
+
+	ret = tb_domain_disconnect_pcie_paths(tb);
+	if (ret)
+		return ret;
+
+	return bus_for_each_dev(&tb_bus_type, NULL, tb, disconnect_xdomain);
+}
+
 int tb_domain_init(void)
 {
-	return bus_register(&tb_bus_type);
+	int ret;
+
+	ret = tb_xdomain_init();
+	if (ret)
+		return ret;
+	ret = bus_register(&tb_bus_type);
+	if (ret)
+		tb_xdomain_exit();
+
+	return ret;
 }
 
 void tb_domain_exit(void)
@@ -453,4 +641,5 @@ void tb_domain_exit(void)
 	bus_unregister(&tb_bus_type);
 	ida_destroy(&tb_domain_ida);
 	tb_switch_exit();
+	tb_xdomain_exit();
 }