From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: linux-usb@vger.kernel.org
Cc: Andreas Noever <andreas.noever@gmail.com>,
Michael Jamet <michael.jamet@intel.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Yehezkel Bernat <YehezkelShB@gmail.com>,
Rajmohan Mani <rajmohan.mani@intel.com>,
Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>,
Lukas Wunner <lukas@wunner.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Mario.Limonciello@dell.com,
Anthony Wong <anthony.wong@canonical.com>,
Oliver Neukum <oneukum@suse.com>,
Christian Kellner <ckellner@redhat.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 25/25] thunderbolt: Update documentation with the USB4 information
Date: Wed, 23 Oct 2019 14:21:54 +0300 [thread overview]
Message-ID: <20191023112154.64235-26-mika.westerberg@linux.intel.com> (raw)
In-Reply-To: <20191023112154.64235-1-mika.westerberg@linux.intel.com>
Update user's and administrator's guide to mention USB4, how it relates
to Thunderbolt (it is public spec of Thunderbolt 3) and and how it is
supported in Linux.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
Documentation/admin-guide/thunderbolt.rst | 25 ++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst
index 898ad78f3cc7..f44c77860870 100644
--- a/Documentation/admin-guide/thunderbolt.rst
+++ b/Documentation/admin-guide/thunderbolt.rst
@@ -1,6 +1,23 @@
-=============
- Thunderbolt
-=============
+======================
+ Thunderbolt and USB4
+======================
+USB4 is a public spec based on Thunderbolt 3 with some differences at the
+register level among other things. There are two different implementations
+available: firmware connection manager and software connection manager.
+Typically PCs come with a firmware connection manager for Thunderbolt 3 and
+early USB4 capable systems. Apple systems on the other hand use software
+connection manager and the later USB4 compliant devices follow the suit.
+
+The Linux Thunderbolt driver supports both and can detect at runtime which
+connection manager implementation is to be used. To be on the safe side the
+software connection manager in Linux also advertises security level
+``user`` which means PCIe tunneling is disabled by default. The
+documentation below applies to both implementations with the exception that
+the software connection manager only supports ``user`` security level and
+is expected to be accompanied with an IOMMU based DMA protection.
+
+Security levels and how to use them
+-----------------------------------
The interface presented here is not meant for end users. Instead there
should be a userspace tool that handles all the low-level details, keeps
a database of the authorized devices and prompts users for new connections.
@@ -18,8 +35,6 @@ This will authorize all devices automatically when they appear. However,
keep in mind that this bypasses the security levels and makes the system
vulnerable to DMA attacks.
-Security levels and how to use them
------------------------------------
Starting with Intel Falcon Ridge Thunderbolt controller there are 4
security levels available. Intel Titan Ridge added one more security level
(usbonly). The reason for these is the fact that the connected devices can
--
2.23.0
next prev parent reply other threads:[~2019-10-23 11:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-23 11:21 [PATCH 00/25] thunderbolt: Add support for USB4 Mika Westerberg
2019-10-23 11:21 ` [PATCH 01/25] thunderbolt: Introduce tb_switch_is_icm() Mika Westerberg
2019-10-23 11:21 ` [PATCH 02/25] thunderbolt: Log switch route string on config read/write timeout Mika Westerberg
2019-10-23 11:21 ` [PATCH 03/25] thunderbolt: Log error if adding switch fails Mika Westerberg
2019-10-23 11:21 ` [PATCH 04/25] thunderbolt: Convert basic adapter register names to follow the USB4 spec Mika Westerberg
2019-10-23 11:21 ` [PATCH 05/25] thunderbolt: Convert PCIe " Mika Westerberg
2019-10-23 11:21 ` [PATCH 06/25] thunderbolt: Convert DP " Mika Westerberg
2019-10-23 11:21 ` [PATCH 07/25] thunderbolt: Make tb_sw_write() take const parameter Mika Westerberg
2019-10-23 11:21 ` [PATCH 08/25] thunderbolt: Add helper macro to iterate over switch ports Mika Westerberg
2019-10-23 11:21 ` [PATCH 09/25] thunderbolt: Refactor add_switch() into two functions Mika Westerberg
2019-10-23 11:21 ` [PATCH 10/25] thunderbolt: Add support for lane bonding Mika Westerberg
2019-10-23 11:21 ` [PATCH 11/25] thunderbolt: Add default linking between lane adapters if not provided by DROM Mika Westerberg
2019-10-23 11:21 ` [PATCH 12/25] thunderbolt: Expand controller name in tb_switch_is_xy() Mika Westerberg
2019-10-23 11:21 ` [PATCH 13/25] thunderbolt: Add downstream PCIe port mappings for Alpine and Titan Ridge Mika Westerberg
2019-10-23 11:21 ` [PATCH 14/25] thunderbolt: Add Display Port CM handshake for Titan Ridge devices Mika Westerberg
2019-10-23 11:21 ` [PATCH 15/25] thunderbolt: Add Display Port adapter pairing and resource management Mika Westerberg
2019-10-23 11:21 ` [PATCH 16/25] thunderbolt: Add bandwidth management for Display Port tunnels Mika Westerberg
2019-10-23 11:21 ` [PATCH 17/25] thunderbolt: Do not start firmware unless asked by the user Mika Westerberg
2019-10-23 11:21 ` [PATCH 18/25] thunderbolt: Make tb_find_port() available to other files Mika Westerberg
2019-10-23 11:21 ` [PATCH 19/25] thunderbolt: Call tb_eeprom_get_drom_offset() from tb_eeprom_read_n() Mika Westerberg
2019-10-23 11:21 ` [PATCH 20/25] thunderbolt: Add initial support for USB4 Mika Westerberg
2019-10-23 11:21 ` [PATCH 21/25] thunderbolt: Update Kconfig entry to USB4 Mika Westerberg
2019-10-23 11:21 ` [PATCH 22/25] thunderbolt: Make tb_switch_find_cap() available to other files Mika Westerberg
2019-10-23 11:21 ` [PATCH 23/25] thunderbolt: Add support for Time Management Unit Mika Westerberg
2019-10-23 11:21 ` [PATCH 24/25] thunderbolt: Add support for USB 3.x tunnels Mika Westerberg
2019-10-23 11:21 ` Mika Westerberg [this message]
2019-10-23 15:55 ` [PATCH 00/25] thunderbolt: Add support for USB4 Mario.Limonciello
2019-10-23 16:18 ` Mika Westerberg
2019-11-01 11:43 ` Mika Westerberg
2019-11-04 14:31 ` Greg Kroah-Hartman
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