thunderbolt: Add control channel interface

Thunderbolt devices are configured by reading/writing into their
configuration space (similar to pci). This is done by sending packets
through the NHI (native host interface) onto the control channel.

This patch handles the low level packet based protocol and exposes
higher level operations like tb_cfg_read/tb_cfg_write.
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/thunderbolt/Makefile

 obj-${CONFIG_THUNDERBOLT} := thunderbolt.o
-thunderbolt-objs := nhi.o
+thunderbolt-objs := nhi.o ctl.o
 

drivers/thunderbolt/ctl.h

+/*
+ * Thunderbolt Cactus Ridge driver - control channel and configuration commands
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ */
+
+#ifndef _TB_CFG
+#define _TB_CFG
+
+#include "nhi.h"
+
+/* control channel */
+struct tb_ctl;
+
+typedef void (*hotplug_cb)(void *data, u64 route, u8 port, bool unplug);
+
+struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, hotplug_cb cb, void *cb_data);
+void tb_ctl_start(struct tb_ctl *ctl);
+void tb_ctl_stop(struct tb_ctl *ctl);
+void tb_ctl_free(struct tb_ctl *ctl);
+
+/* configuration commands */
+
+#define TB_CFG_DEFAULT_TIMEOUT 5000 /* msec */
+
+enum tb_cfg_space {
+	TB_CFG_HOPS = 0,
+	TB_CFG_PORT = 1,
+	TB_CFG_SWITCH = 2,
+	TB_CFG_COUNTERS = 3,
+};
+
+enum tb_cfg_error {
+	TB_CFG_ERROR_PORT_NOT_CONNECTED = 0,
+	TB_CFG_ERROR_INVALID_CONFIG_SPACE = 2,
+	TB_CFG_ERROR_NO_SUCH_PORT = 4,
+	TB_CFG_ERROR_ACK_PLUG_EVENT = 7, /* send as reply to TB_CFG_PKG_EVENT */
+	TB_CFG_ERROR_LOOP = 8,
+};
+
+struct tb_cfg_result {
+	u64 response_route;
+	u32 response_port; /*
+			    * If err = 1 then this is the port that send the
+			    * error.
+			    * If err = 0 and if this was a cfg_read/write then
+			    * this is the the upstream port of the responding
+			    * switch.
+			    * Otherwise the field is set to zero.
+			    */
+	int err; /* negative errors, 0 for success, 1 for tb errors */
+	enum tb_cfg_error tb_error; /* valid if err == 1 */
+};
+
+
+int tb_cfg_error(struct tb_ctl *ctl, u64 route, u32 port,
+		 enum tb_cfg_error error);
+struct tb_cfg_result tb_cfg_reset(struct tb_ctl *ctl, u64 route,
+				  int timeout_msec);
+struct tb_cfg_result tb_cfg_read_raw(struct tb_ctl *ctl, void *buffer,
+				     u64 route, u32 port,
+				     enum tb_cfg_space space, u32 offset,
+				     u32 length, int timeout_msec);
+struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, void *buffer,
+				      u64 route, u32 port,
+				      enum tb_cfg_space space, u32 offset,
+				      u32 length, int timeout_msec);
+int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
+		enum tb_cfg_space space, u32 offset, u32 length);
+int tb_cfg_write(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
+		 enum tb_cfg_space space, u32 offset, u32 length);
+int tb_cfg_get_upstream_port(struct tb_ctl *ctl, u64 route);
+
+
+#endif