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, 35 insertions, 4 deletions

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index ea21d927bd09..74af9d4929ab 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -9,6 +9,7 @@
 
 #include <linux/nvmem-provider.h>
 #include <linux/pci.h>
+#include <linux/thunderbolt.h>
 #include <linux/uuid.h>
 
 #include "tb_regs.h"
@@ -109,14 +110,25 @@ struct tb_switch {
 
 /**
  * struct tb_port - a thunderbolt port, part of a tb_switch
+ * @config: Cached port configuration read from registers
+ * @sw: Switch the port belongs to
+ * @remote: Remote port (%NULL if not connected)
+ * @xdomain: Remote host (%NULL if not connected)
+ * @cap_phy: Offset, zero if not found
+ * @port: Port number on switch
+ * @disabled: Disabled by eeprom
+ * @dual_link_port: If the switch is connected using two ports, points
+ *		    to the other port.
+ * @link_nr: Is this primary or secondary port on the dual_link.
  */
 struct tb_port {
 	struct tb_regs_port_header config;
 	struct tb_switch *sw;
-	struct tb_port *remote; /* remote port, NULL if not connected */
-	int cap_phy; /* offset, zero if not found */
-	u8 port; /* port number on switch */
-	bool disabled; /* disabled by eeprom */
+	struct tb_port *remote;
+	struct tb_xdomain *xdomain;
+	int cap_phy;
+	u8 port;
+	bool disabled;
 	struct tb_port *dual_link_port;
 	u8 link_nr:1;
 };
@@ -189,6 +201,8 @@ struct tb_path {
  * @add_switch_key: Add key to switch
  * @challenge_switch_key: Challenge switch using key
  * @disconnect_pcie_paths: Disconnects PCIe paths before NVM update
+ * @approve_xdomain_paths: Approve (establish) XDomain DMA paths
+ * @disconnect_xdomain_paths: Disconnect XDomain DMA paths
  */
 struct tb_cm_ops {
 	int (*driver_ready)(struct tb *tb);
@@ -205,6 +219,8 @@ struct tb_cm_ops {
 	int (*challenge_switch_key)(struct tb *tb, struct tb_switch *sw,
 				    const u8 *challenge, u8 *response);
 	int (*disconnect_pcie_paths)(struct tb *tb);
+	int (*approve_xdomain_paths)(struct tb *tb, struct tb_xdomain *xd);
+	int (*disconnect_xdomain_paths)(struct tb *tb, struct tb_xdomain *xd);
 };
 
 static inline void *tb_priv(struct tb *tb)
@@ -331,6 +347,8 @@ extern struct device_type tb_switch_type;
 int tb_domain_init(void);
 void tb_domain_exit(void);
 void tb_switch_exit(void);
+int tb_xdomain_init(void);
+void tb_xdomain_exit(void);
 
 struct tb *tb_domain_alloc(struct tb_nhi *nhi, size_t privsize);
 int tb_domain_add(struct tb *tb);
@@ -343,6 +361,9 @@ int tb_domain_approve_switch(struct tb *tb, struct tb_switch *sw);
 int tb_domain_approve_switch_key(struct tb *tb, struct tb_switch *sw);
 int tb_domain_challenge_switch_key(struct tb *tb, struct tb_switch *sw);
 int tb_domain_disconnect_pcie_paths(struct tb *tb);
+int tb_domain_approve_xdomain_paths(struct tb *tb, struct tb_xdomain *xd);
+int tb_domain_disconnect_xdomain_paths(struct tb *tb, struct tb_xdomain *xd);
+int tb_domain_disconnect_all_paths(struct tb *tb);
 
 static inline void tb_domain_put(struct tb *tb)
 {
@@ -422,4 +443,14 @@ static inline u64 tb_downstream_route(struct tb_port *port)
 	       | ((u64) port->port << (port->sw->config.depth * 8));
 }
 
+bool tb_xdomain_handle_request(struct tb *tb, enum tb_cfg_pkg_type type,
+			       const void *buf, size_t size);
+struct tb_xdomain *tb_xdomain_alloc(struct tb *tb, struct device *parent,
+				    u64 route, const uuid_t *local_uuid,
+				    const uuid_t *remote_uuid);
+void tb_xdomain_add(struct tb_xdomain *xd);
+void tb_xdomain_remove(struct tb_xdomain *xd);
+struct tb_xdomain *tb_xdomain_find_by_link_depth(struct tb *tb, u8 link,
+						 u8 depth);
+
 #endif