From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail7-214.sinamail.sina.com.cn (mail7-214.sinamail.sina.com.cn. [202.108.7.214]) by gmr-mx.google.com with SMTP id y4si1291612vsa.2.2018.10.09.23.50.48 for ; Tue, 09 Oct 2018 23:50:49 -0700 (PDT) From: Wesley Sheng Subject: [PATCH v3] NTB: switchtec_ntb: Update switchtec documentation with pre-requisites for NTB Date: Wed, 10 Oct 2018 21:47:47 +0800 Message-Id: <1539179267-26534-1-git-send-email-wesleyshenggit@sina.com> To: kurt.schwemmer@microsemi.com, bhelgaas@google.com, logang@deltatee.com, corbet@lwn.net Cc: linux-ntb@googlegroups.com, linux-pci@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Wesley Yung , Kelvin Cao , Wesley Sheng List-ID: From: Wesley Yung The ntb_hw_switchtec driver has requirements on kernel configuration so we add these notes to the documentation and also clean up a few other sentences in the documentation. Signed-off-by: Wesley Yung Signed-off-by: Kelvin Cao Signed-off-by: Wesley Sheng --- Documentation/switchtec.txt | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) diff --git a/Documentation/switchtec.txt b/Documentation/switchtec.txt index f788264..d6f04dcc 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. -- 2.7.4