thunderbolt: Add 'boot' attribute for devices

In various cases, Thunderbolt device can be connected by ICM on boot
without waiting for approval from user. Most cases are related to
OEM-specific BIOS configurations. This information is interesting for
user-space as if the device isn't in SW ACL, it may create a friction in
the user experience where the device is automatically authorized if it's
connected on boot but requires an explicit user action if connected
after OS is up. User-space can use this information to suggest adding
the device to SW ACL for auto-authorization on later connections.

Signed-off-by: Yehezkel Bernat <[e-mail]>
Signed-off-by: Mika Westerberg <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>

Documentation/ABI/testing/sysfs-bus-thunderbolt

···
 		   the device did not contain a key at all, and
 		   EKEYREJECTED if the challenge response did not match.
 
+What: /sys/bus/thunderbolt/devices/.../boot
+Date:		Jun 2018
+KernelVersion:	4.17
+Contact:	[e-mail]
+Description:	This attribute contains 1 if Thunderbolt device was already
+		authorized on boot and 0 otherwise.
+
 What: /sys/bus/thunderbolt/devices/.../key
 Date:		Sep 2017
 KernelVersion:	4.13

drivers/thunderbolt/icm.c

···
 static void add_switch(struct tb_switch *parent_sw, u64 route,
 		       const uuid_t *uuid, u8 connection_id, u8 connection_key,
 		       u8 link, u8 depth, enum tb_security_level security_level,
-		       bool authorized)
+		       bool authorized, bool boot)
 {
 	struct tb_switch *sw;
 
···
 	sw->depth = depth;
 	sw->authorized = authorized;
 	sw->security_level = security_level;
+	sw->boot = boot;
 
 	/* Link the two switches now */
 	tb_port_at(route, parent_sw)->remote = tb_upstream_port(sw);
···
 
 static void update_switch(struct tb_switch *parent_sw, struct tb_switch *sw,
 			  u64 route, u8 connection_id, u8 connection_key,
-			  u8 link, u8 depth)
+			  u8 link, u8 depth, bool boot)
 {
 	/* Disconnect from parent */
 	tb_port_at(tb_route(sw), parent_sw)->remote = NULL;
···
 	sw->connection_key = connection_key;
 	sw->link = link;
 	sw->depth = depth;
+	sw->boot = boot;
 
 	/* This switch still exists */
 	sw->is_unplugged = false;
···
 	bool authorized = false;
 	struct tb_xdomain *xd;
 	u8 link, depth;
+	bool boot;
 	u64 route;
 	int ret;
 
···
 	authorized = pkg->link_info & ICM_LINK_INFO_APPROVED;
 	security_level = (pkg->hdr.flags & ICM_FLAGS_SLEVEL_MASK) >>
 			 ICM_FLAGS_SLEVEL_SHIFT;
+	boot = pkg->link_info & ICM_LINK_INFO_BOOT;
 
 	if (pkg->link_info & ICM_LINK_INFO_REJECTED) {
 		tb_info(tb, "switch at %u.%u was rejected by ICM firmware because topology limit exceeded\n",
···
 		if (sw->depth == depth && sw_phy_port == phy_port &&
 		    !!sw->authorized == authorized) {
 			update_switch(parent_sw, sw, route, pkg->connection_id,
-				      pkg->connection_key, link, depth);
+				      pkg->connection_key, link, depth, boot);
 			tb_switch_put(sw);
 			return;
 		}
···
 
 	add_switch(parent_sw, route, &pkg->ep_uuid, pkg->connection_id,
 		   pkg->connection_key, link, depth, security_level,
-		   authorized);
+		   authorized, boot);
 
 	tb_switch_put(parent_sw);
 }

drivers/thunderbolt/switch.c

···
 }
 static DEVICE_ATTR_RW(authorized);
 
+static ssize_t boot_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct tb_switch *sw = tb_to_switch(dev);
+
+	return sprintf(buf, "%u\n", sw->boot);
+}
+static DEVICE_ATTR_RO(boot);
+
 static ssize_t device_show(struct device *dev, struct device_attribute *attr,
 			   char *buf)
 {
···
 
 static struct attribute *switch_attrs[] = {
 	&dev_attr_authorized.attr,
+	&dev_attr_boot.attr,
 	&dev_attr_device.attr,
 	&dev_attr_device_name.attr,
 	&dev_attr_key.attr,
···
 	} else if (attr == &dev_attr_nvm_authenticate.attr ||
 		   attr == &dev_attr_nvm_version.attr) {
 		if (sw->dma_port)
+			return attr->mode;
+		return 0;
+	} else if (attr == &dev_attr_boot.attr) {
+		if (tb_route(sw))
 			return attr->mode;
 		return 0;
 	}

drivers/thunderbolt/tb.h

···
  * @nvm: Pointer to the NVM if the switch has one (%NULL otherwise)
  * @no_nvm_upgrade: Prevent NVM upgrade of this switch
  * @safe_mode: The switch is in safe-mode
+ * @boot: Whether the switch was already authorized on boot or not
  * @authorized: Whether the switch is authorized by user or policy
  * @work: Work used to automatically authorize a switch
  * @security_level: Switch supported security level
···
 	struct tb_switch_nvm *nvm;
 	bool no_nvm_upgrade;
 	bool safe_mode;
+	bool boot;
 	unsigned int authorized;
 	struct work_struct work;
 	enum tb_security_level security_level;

drivers/thunderbolt/tb_msgs.h

···
 #define ICM_LINK_INFO_DEPTH_MASK	GENMASK(7, 4)
 #define ICM_LINK_INFO_APPROVED		BIT(8)
 #define ICM_LINK_INFO_REJECTED		BIT(9)
+#define ICM_LINK_INFO_BOOT		BIT(10)
 
 struct icm_fr_pkg_approve_device {
 	struct icm_pkg_header hdr;