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, 123 insertions, 0 deletions

diff --git a/drivers/thunderbolt/tb_msgs.h b/drivers/thunderbolt/tb_msgs.h
index f2b2550cd97c..b0a092baa605 100644
--- a/drivers/thunderbolt/tb_msgs.h
+++ b/drivers/thunderbolt/tb_msgs.h
@@ -101,11 +101,14 @@ enum icm_pkg_code {
 	ICM_CHALLENGE_DEVICE = 0x5,
 	ICM_ADD_DEVICE_KEY = 0x6,
 	ICM_GET_ROUTE = 0xa,
+	ICM_APPROVE_XDOMAIN = 0x10,
 };
 
 enum icm_event_code {
 	ICM_EVENT_DEVICE_CONNECTED = 3,
 	ICM_EVENT_DEVICE_DISCONNECTED = 4,
+	ICM_EVENT_XDOMAIN_CONNECTED = 6,
+	ICM_EVENT_XDOMAIN_DISCONNECTED = 7,
 };
 
 struct icm_pkg_header {
@@ -188,6 +191,25 @@ struct icm_fr_event_device_disconnected {
 	u16 link_info;
 };
 
+struct icm_fr_event_xdomain_connected {
+	struct icm_pkg_header hdr;
+	u16 reserved;
+	u16 link_info;
+	uuid_t remote_uuid;
+	uuid_t local_uuid;
+	u32 local_route_hi;
+	u32 local_route_lo;
+	u32 remote_route_hi;
+	u32 remote_route_lo;
+};
+
+struct icm_fr_event_xdomain_disconnected {
+	struct icm_pkg_header hdr;
+	u16 reserved;
+	u16 link_info;
+	uuid_t remote_uuid;
+};
+
 struct icm_fr_pkg_add_device_key {
 	struct icm_pkg_header hdr;
 	uuid_t ep_uuid;
@@ -224,6 +246,28 @@ struct icm_fr_pkg_challenge_device_response {
 	u32 response[8];
 };
 
+struct icm_fr_pkg_approve_xdomain {
+	struct icm_pkg_header hdr;
+	u16 reserved;
+	u16 link_info;
+	uuid_t remote_uuid;
+	u16 transmit_path;
+	u16 transmit_ring;
+	u16 receive_path;
+	u16 receive_ring;
+};
+
+struct icm_fr_pkg_approve_xdomain_response {
+	struct icm_pkg_header hdr;
+	u16 reserved;
+	u16 link_info;
+	uuid_t remote_uuid;
+	u16 transmit_path;
+	u16 transmit_ring;
+	u16 receive_path;
+	u16 receive_ring;
+};
+
 /* Alpine Ridge only messages */
 
 struct icm_ar_pkg_get_route {
@@ -240,4 +284,83 @@ struct icm_ar_pkg_get_route_response {
 	u32 route_lo;
 };
 
+/* XDomain messages */
+
+struct tb_xdomain_header {
+	u32 route_hi;
+	u32 route_lo;
+	u32 length_sn;
+};
+
+#define TB_XDOMAIN_LENGTH_MASK	GENMASK(5, 0)
+#define TB_XDOMAIN_SN_MASK	GENMASK(28, 27)
+#define TB_XDOMAIN_SN_SHIFT	27
+
+enum tb_xdp_type {
+	UUID_REQUEST_OLD = 1,
+	UUID_RESPONSE = 2,
+	PROPERTIES_REQUEST,
+	PROPERTIES_RESPONSE,
+	PROPERTIES_CHANGED_REQUEST,
+	PROPERTIES_CHANGED_RESPONSE,
+	ERROR_RESPONSE,
+	UUID_REQUEST = 12,
+};
+
+struct tb_xdp_header {
+	struct tb_xdomain_header xd_hdr;
+	uuid_t uuid;
+	u32 type;
+};
+
+struct tb_xdp_properties {
+	struct tb_xdp_header hdr;
+	uuid_t src_uuid;
+	uuid_t dst_uuid;
+	u16 offset;
+	u16 reserved;
+};
+
+struct tb_xdp_properties_response {
+	struct tb_xdp_header hdr;
+	uuid_t src_uuid;
+	uuid_t dst_uuid;
+	u16 offset;
+	u16 data_length;
+	u32 generation;
+	u32 data[0];
+};
+
+/*
+ * Max length of data array single XDomain property response is allowed
+ * to carry.
+ */
+#define TB_XDP_PROPERTIES_MAX_DATA_LENGTH	\
+	(((256 - 4 - sizeof(struct tb_xdp_properties_response))) / 4)
+
+/* Maximum size of the total property block in dwords we allow */
+#define TB_XDP_PROPERTIES_MAX_LENGTH		500
+
+struct tb_xdp_properties_changed {
+	struct tb_xdp_header hdr;
+	uuid_t src_uuid;
+};
+
+struct tb_xdp_properties_changed_response {
+	struct tb_xdp_header hdr;
+};
+
+enum tb_xdp_error {
+	ERROR_SUCCESS,
+	ERROR_UNKNOWN_PACKET,
+	ERROR_UNKNOWN_DOMAIN,
+	ERROR_NOT_SUPPORTED,
+	ERROR_NOT_READY,
+};
+
+struct tb_xdp_error_response {
+	struct tb_xdp_header hdr;
+	u32 error;
+};
+
 #endif