[PATCH v2] NTB: switchtec_ntb: Update switchtec documentation with pre-requisites for NTB

From: <Wesley.Sheng@microchip.com>
To: <kurt.schwemmer@microsemi.com>, <logang@deltatee.com>,
	<bhelgaas@google.com>, <corbet@lwn.net>
Cc: <linux-pci@vger.kernel.org>, <linux-doc@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <Wesley.Sheng@microchip.com>,
	<linux-ntb@googlegroups.com>, <linux-ntb@googlegroups.com>
Subject: [PATCH v2] NTB: switchtec_ntb: Update switchtec documentation with pre-requisites for NTB
Date: Thu, 27 Sep 2018 06:36:22 +0000	[thread overview]
Message-ID: <DM2PR11MB010585C1D5584683B31CCF5495140@DM2PR11MB0105.namprd11.prod.outlook.com> (raw)

Update switchtec documentation
1.add pre-requisites for NTB driver
2.misc updates
 change NTB hardware driver name to ntb_hw_switchtec
 update the description of 2 partitions limit
 add reference to Linux Documentation/ntb.txt
 add use of term 'Command ID'
 add use of term 'Command Return Value'
 add a missing ')'

Signed-off-by: Kelvin Cao <kelvin.cao@microchip.com>
Signed-off-by: Wesley Yung <Wesley.Yung@microchip.com>
Signed-off-by: Wesley Sheng <Wesley.sheng@microchip.com>

---
 Documentation/switchtec.txt | 30 ++++++++++++++--------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/Documentation/switchtec.txt b/Documentation/switchtec.txt index f788264..40e839d 100644
--- a/Documentation/switchtec.txt
+++ b/Documentation/switchtec.txt
@@ -23,7 +23,7 @@ The primary means of communicating with the Switchtec management firmware is
 through the Memory-mapped Remote Procedure Call (MRPC) interface.
 Commands are submitted to the interface with a 4-byte command
 identifier and up to 1KB of command specific data. The firmware will 
-respond with a 4 bytes return code and up to 1KB of command specific
+respond with a 4-byte return code and up to 1KB of command specific
 data. The interface only processes a single command at a time.
 
 
@@ -36,8 +36,8 @@ device: /dev/switchtec#, one for each management endpoint in the system.
 The char device has the following semantics:
 
 * A write must consist of at least 4 bytes and no more than 1028 bytes.
-  The first four bytes will be interpreted as the command to run and
-  the remainder will be used as the input data. A write will send the
+  The first 4 bytes will be interpreted as the Command ID and the  
+ remainder will be used as the input data. A write will send the
   command to the firmware to begin processing.
 
 * Each write must be followed by exactly one read. Any double write will
 @@ -45,9 +45,9 @@ The char device has the following semantics:
   produce an error.
 
 * A read will block until the firmware completes the command and return
-  the four bytes of status plus up to 1024 bytes of output data. (The
-  length will be specified by the size parameter of the read call --
-  reading less than 4 bytes will produce an error.
+  the 4-byte Command Return Value plus up to 1024 bytes of output  
+ data. (The length will be specified by the size parameter of the read  
+ call -- reading less than 4 bytes will produce an error.)
 
 * The poll call will also be supported for userspace applications that
   need to do other things while waiting for the command to complete.
@@ -83,10 +83,20 @@ The following IOCTLs are also supported by the device:
 Non-Transparent Bridge (NTB) Driver
 ===================================
 
-An NTB driver is provided for the switchtec hardware in switchtec_ntb.
-Currently, it only supports switches configured with exactly 2 
-partitions. It also requires the following configuration settings:
+An NTB hardware driver is provided for the Switchtec hardware in 
+ntb_hw_switchtec. Currently, it only supports switches configured with 
+exactly 2 NT partitions and zero or more non-NT partitions. It also 
+requires the following configuration settings:
 
-* Both partitions must be able to access each other's GAS spaces.
+* Both NT partitions must be able to access each other's GAS spaces.
   Thus, the bits in the GAS Access Vector under Management Settings
   must be set to support this.
+* Kernel configuration MUST include support for NTB (CONFIG_NTB needs
+  to be set)
+
+NT EP BAR 2 will be dynamically configured as a Direct Window, and the 
+configuration file does not need to configure it explicitly.
+
+Please refer to Documentation/ntb.txt in Linux source tree for an 
+overall understanding of the Linux NTB stack. ntb_hw_switchtec works as 
+an NTB Hardware Driver in this stack.
