path: root/Documentation/rapidio
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authorAlexandre Bounine <alexandre.bounine@idt.com>2013-07-03 15:08:59 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 16:08:05 -0700
commited5edee2f8547d5c2b28de21cb1471aaea71ee0a (patch)
tree3efad73b8afcbce1e37ea499f6c3d8cc2a7feac2 /Documentation/rapidio
parent3bdbb62fe97537252b22f700009863eeb51aa750 (diff)
rapidio: documentation update
Update RapidIO documentation files to reflect modularization changes. Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Li Yang <leoli@freescale.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Andre van Herk <andre.van.herk@Prodrive.nl> Cc: Micha Nelissen <micha.nelissen@Prodrive.nl> Cc: Stef van Os <stef.van.os@Prodrive.nl> Cc: Jean Delvare <jdelvare@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/rapidio')
2 files changed, 86 insertions, 13 deletions
diff --git a/Documentation/rapidio/rapidio.txt b/Documentation/rapidio/rapidio.txt
index a9c16c979da2..717f5aa388b1 100644
--- a/Documentation/rapidio/rapidio.txt
+++ b/Documentation/rapidio/rapidio.txt
@@ -73,28 +73,44 @@ data structure. This structure includes lists of all devices and local master
ports that form the same network. It also contains a pointer to the default
master port that is used to communicate with devices within the network.
+2.5 Device Drivers
+RapidIO device-specific drivers follow Linux Kernel Driver Model and are
+intended to support specific RapidIO devices attached to the RapidIO network.
+2.6 Subsystem Interfaces
+RapidIO interconnect specification defines features that may be used to provide
+one or more common service layers for all participating RapidIO devices. These
+common services may act separately from device-specific drivers or be used by
+device-specific drivers. Example of such service provider is the RIONET driver
+which implements Ethernet-over-RapidIO interface. Because only one driver can be
+registered for a device, all common RapidIO services have to be registered as
+subsystem interfaces. This allows to have multiple common services attached to
+the same device without blocking attachment of a device-specific driver.
3. Subsystem Initialization
In order to initialize the RapidIO subsystem, a platform must initialize and
register at least one master port within the RapidIO network. To register mport
-within the subsystem controller driver initialization code calls function
+within the subsystem controller driver's initialization code calls function
rio_register_mport() for each available master port.
-RapidIO subsystem uses subsys_initcall() or device_initcall() to perform
-controller initialization (depending on controller device type).
After all active master ports are registered with a RapidIO subsystem,
an enumeration and/or discovery routine may be called automatically or
by user-space command.
+RapidIO subsystem can be configured to be built as a statically linked or
+modular component of the kernel (see details below).
4. Enumeration and Discovery
4.1 Overview
-RapidIO subsystem configuration options allow users to specify enumeration and
+RapidIO subsystem configuration options allow users to build enumeration and
discovery methods as statically linked components or loadable modules.
An enumeration/discovery method implementation and available input parameters
define how any given method can be attached to available RapidIO mports:
@@ -115,8 +131,8 @@ several methods to initiate an enumeration and/or discovery process:
endpoint waits for enumeration to be completed. If the specified timeout
expires the discovery process is terminated without obtaining RapidIO network
information. NOTE: a timed out discovery process may be restarted later using
- a user-space command as it is described later if the given endpoint was
- enumerated successfully.
+ a user-space command as it is described below (if the given endpoint was
+ enumerated successfully).
(b) Statically linked enumeration and discovery process can be started by
a command from user space. This initiation method provides more flexibility
@@ -138,15 +154,42 @@ When a network scan process is started it calls an enumeration or discovery
routine depending on the configured role of a master port: host or agent.
Enumeration is performed by a master port if it is configured as a host port by
-assigning a host device ID greater than or equal to zero. A host device ID is
-assigned to a master port through the kernel command line parameter "riohdid=",
-or can be configured in a platform-specific manner. If the host device ID for
-a specific master port is set to -1, the discovery process will be performed
-for it.
+assigning a host destination ID greater than or equal to zero. The host
+destination ID can be assigned to a master port using various methods depending
+on RapidIO subsystem build configuration:
+ (a) For a statically linked RapidIO subsystem core use command line parameter
+ "rapidio.hdid=" with a list of destination ID assignments in order of mport
+ device registration. For example, in a system with two RapidIO controllers
+ the command line parameter "rapidio.hdid=-1,7" will result in assignment of
+ the host destination ID=7 to the second RapidIO controller, while the first
+ one will be assigned destination ID=-1.
+ (b) If the RapidIO subsystem core is built as a loadable module, in addition
+ to the method shown above, the host destination ID(s) can be specified using
+ traditional methods of passing module parameter "hdid=" during its loading:
+ - from command line: "modprobe rapidio hdid=-1,7", or
+ - from modprobe configuration file using configuration command "options",
+ like in this example: "options rapidio hdid=-1,7". An example of modprobe
+ configuration file is provided in the section below.
+ (i) if "hdid=" parameter is omitted all available mport will be assigned
+ destination ID = -1;
+ (ii) the "hdid=" parameter in systems with multiple mports can have
+ destination ID assignments omitted from the end of list (default = -1).
+If the host device ID for a specific master port is set to -1, the discovery
+process will be performed for it.
The enumeration and discovery routines use RapidIO maintenance transactions
to access the configuration space of devices.
+NOTE: If RapidIO switch-specific device drivers are built as loadable modules
+they must be loaded before enumeration/discovery process starts.
+This requirement is cased by the fact that enumeration/discovery methods invoke
+vendor-specific callbacks on early stages.
4.2 Automatic Start of Enumeration and Discovery
@@ -266,7 +309,36 @@ method's module initialization routine calls rio_register_scan() to attach
an enumerator to a specified mport device (or devices). The basic enumerator
implementation demonstrates this process.
-5. References
+4.6 Using Loadable RapidIO Switch Drivers
+In the case when RapidIO switch drivers are built as loadable modules a user
+must ensure that they are loaded before the enumeration/discovery starts.
+This process can be automated by specifying pre- or post- dependencies in the
+RapidIO-specific modprobe configuration file as shown in the example below.
+ File /etc/modprobe.d/rapidio.conf:
+ ----------------------------------
+ # Configure RapidIO subsystem modules
+ # Set enumerator host destination ID (overrides kernel command line option)
+ options rapidio hdid=-1,2
+ # Load RapidIO switch drivers immediately after rapidio core module was loaded
+ softdep rapidio post: idt_gen2 idtcps tsi57x
+ # OR :
+ # Load RapidIO switch drivers just before rio-scan enumerator module is loaded
+ softdep rio-scan pre: idt_gen2 idtcps tsi57x
+ --------------------------
+NOTE: In the example above, one of "softdep" commands must be removed or
+commented out to keep required module loading sequence.
+A. References
[1] RapidIO Trade Association. RapidIO Interconnect Specifications.
diff --git a/Documentation/rapidio/sysfs.txt b/Documentation/rapidio/sysfs.txt
index 19878179da4c..271438c0617f 100644
--- a/Documentation/rapidio/sysfs.txt
+++ b/Documentation/rapidio/sysfs.txt
@@ -40,6 +40,7 @@ device_rev - returns the device revision level
(see 4.1 for switch specific details)
lprev - returns name of previous device (switch) on the path to the device
that that owns this attribute
+ modalias - returns the device modalias
In addition to the files listed above, each device has a binary attribute file
that allows read/write access to the device configuration registers using

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