thunderbolt: Add functions for allocating and releasing HopIDs

Each port has a separate path configuration space that is used for
finding the next hop (switch) in the path. HopID is an index to this
configuration space. HopIDs 0 - 7 are reserved by the protocol.

In order to get next available HopID for each direction we provide two
pairs of helper functions that can be used to allocate and release
HopIDs for a given port.

While there remove obsolete TODO comment.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index d1f8e9722f33..1cb5009195f9 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -127,6 +127,8 @@ struct tb_switch {
  * @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.
+ * @in_hopids: Currently allocated input HopIDs
+ * @out_hopids: Currently allocated output HopIDs
  */
 struct tb_port {
 	struct tb_regs_port_header config;
@@ -139,6 +141,8 @@ struct tb_port {
 	bool disabled;
 	struct tb_port *dual_link_port;
 	u8 link_nr:1;
+	struct ida in_hopids;
+	struct ida out_hopids;
 };
 
 /**
@@ -194,6 +198,9 @@ struct tb_path {
 	int path_length; /* number of hops */
 };
 
+/* HopIDs 0-7 are reserved by the Thunderbolt protocol */
+#define TB_PATH_MIN_HOPID	8
+
 /**
  * struct tb_cm_ops - Connection manager specific operations vector
  * @driver_ready: Called right after control channel is started. Used by
@@ -453,6 +460,10 @@ static inline bool tb_switch_is_er(const struct tb_switch *sw)
 int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged);
 int tb_port_add_nfc_credits(struct tb_port *port, int credits);
 int tb_port_clear_counter(struct tb_port *port, int counter);
+int tb_port_alloc_in_hopid(struct tb_port *port, int hopid, int max_hopid);
+void tb_port_release_in_hopid(struct tb_port *port, int hopid);
+int tb_port_alloc_out_hopid(struct tb_port *port, int hopid, int max_hopid);
+void tb_port_release_out_hopid(struct tb_port *port, int hopid);
 
 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec);
 int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap);