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, 26 insertions, 0 deletions

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 694cebb50f72..7625c3b81f84 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -683,5 +683,31 @@ struct fsl_mc_device_id {
 	const char obj_type[16];
 };
 
+/**
+ * struct tb_service_id - Thunderbolt service identifiers
+ * @match_flags: Flags used to match the structure
+ * @protocol_key: Protocol key the service supports
+ * @protocol_id: Protocol id the service supports
+ * @protocol_version: Version of the protocol
+ * @protocol_revision: Revision of the protocol software
+ * @driver_data: Driver specific data
+ *
+ * Thunderbolt XDomain services are exposed as devices where each device
+ * carries the protocol information the service supports. Thunderbolt
+ * XDomain service drivers match against that information.
+ */
+struct tb_service_id {
+	__u32 match_flags;
+	char protocol_key[8 + 1];
+	__u32 protocol_id;
+	__u32 protocol_version;
+	__u32 protocol_revision;
+	kernel_ulong_t driver_data;
+};
+
+#define TBSVC_MATCH_PROTOCOL_KEY	0x0001
+#define TBSVC_MATCH_PROTOCOL_ID		0x0002
+#define TBSVC_MATCH_PROTOCOL_VERSION	0x0004
+#define TBSVC_MATCH_PROTOCOL_REVISION	0x0008
 
 #endif /* LINUX_MOD_DEVICETABLE_H */