diff options
Diffstat (limited to 'Documentation/rapidio')
| -rw-r--r-- | Documentation/rapidio/rapidio.txt | 128 | ||||
| -rw-r--r-- | Documentation/rapidio/sysfs.txt | 17 |
2 files changed, 134 insertions, 11 deletions
diff --git a/Documentation/rapidio/rapidio.txt b/Documentation/rapidio/rapidio.txt index c75694b35d08..a9c16c979da2 100644 --- a/Documentation/rapidio/rapidio.txt +++ b/Documentation/rapidio/rapidio.txt @@ -79,20 +79,63 @@ master port that is used to communicate with devices within the network. 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 -rio_register_mport() for each available master port. After all active master -ports are registered with a RapidIO subsystem, the rio_init_mports() routine -is called to perform enumeration and discovery. +rio_register_mport() for each available master port. -In the current PowerPC-based implementation a subsys_initcall() is specified to -perform controller initialization and mport registration. At the end it directly -calls rio_init_mports() to execute RapidIO enumeration and discovery. +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. 4. Enumeration and Discovery ---------------------------- -When rio_init_mports() is called it scans a list of registered master ports and -calls an enumeration or discovery routine depending on the configured role of a -master port: host or agent. +4.1 Overview +------------ + +RapidIO subsystem configuration options allow users to specify 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: +simply to all available mports OR individually to the specified mport device. + +Depending on selected enumeration/discovery build configuration, there are +several methods to initiate an enumeration and/or discovery process: + + (a) Statically linked enumeration and discovery process can be started + automatically during kernel initialization time using corresponding module + parameters. This was the original method used since introduction of RapidIO + subsystem. Now this method relies on enumerator module parameter which is + 'rio-scan.scan' for existing basic enumeration/discovery method. + When automatic start of enumeration/discovery is used a user has to ensure + that all discovering endpoints are started before the enumerating endpoint + and are waiting for enumeration to be completed. + Configuration option CONFIG_RAPIDIO_DISC_TIMEOUT defines time that discovering + 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. + + (b) Statically linked enumeration and discovery process can be started by + a command from user space. This initiation method provides more flexibility + for a system startup compared to the option (a) above. After all participating + endpoints have been successfully booted, an enumeration process shall be + started first by issuing a user-space command, after an enumeration is + completed a discovery process can be started on all remaining endpoints. + + (c) Modular enumeration and discovery process can be started by a command from + user space. After an enumeration/discovery module is loaded, a network scan + process can be started by issuing a user-space command. + Similar to the option (b) above, an enumerator has to be started first. + + (d) Modular enumeration and discovery process can be started by a module + initialization routine. In this case an enumerating module shall be loaded + first. + +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 @@ -104,8 +147,58 @@ for it. The enumeration and discovery routines use RapidIO maintenance transactions to access the configuration space of devices. -The enumeration process is implemented according to the enumeration algorithm -outlined in the RapidIO Interconnect Specification: Annex I [1]. +4.2 Automatic Start of Enumeration and Discovery +------------------------------------------------ + +Automatic enumeration/discovery start method is applicable only to built-in +enumeration/discovery RapidIO configuration selection. To enable automatic +enumeration/discovery start by existing basic enumerator method set use boot +command line parameter "rio-scan.scan=1". + +This configuration requires synchronized start of all RapidIO endpoints that +form a network which will be enumerated/discovered. Discovering endpoints have +to be started before an enumeration starts to ensure that all RapidIO +controllers have been initialized and are ready to be discovered. Configuration +parameter CONFIG_RAPIDIO_DISC_TIMEOUT defines time (in seconds) which +a discovering endpoint will wait for enumeration to be completed. + +When automatic enumeration/discovery start is selected, basic method's +initialization routine calls rio_init_mports() to perform enumeration or +discovery for all known mport devices. + +Depending on RapidIO network size and configuration this automatic +enumeration/discovery start method may be difficult to use due to the +requirement for synchronized start of all endpoints. + +4.3 User-space Start of Enumeration and Discovery +------------------------------------------------- + +User-space start of enumeration and discovery can be used with built-in and +modular build configurations. For user-space controlled start RapidIO subsystem +creates the sysfs write-only attribute file '/sys/bus/rapidio/scan'. To initiate +an enumeration or discovery process on specific mport device, a user needs to +write mport_ID (not RapidIO destination ID) into that file. The mport_ID is a +sequential number (0 ... RIO_MAX_MPORTS) assigned during mport device +registration. For example for machine with single RapidIO controller, mport_ID +for that controller always will be 0. + +To initiate RapidIO enumeration/discovery on all available mports a user may +write '-1' (or RIO_MPORT_ANY) into the scan attribute file. + +4.4 Basic Enumeration Method +---------------------------- + +This is an original enumeration/discovery method which is available since +first release of RapidIO subsystem code. The enumeration process is +implemented according to the enumeration algorithm outlined in the RapidIO +Interconnect Specification: Annex I [1]. + +This method can be configured as statically linked or loadable module. +The method's single parameter "scan" allows to trigger the enumeration/discovery +process from module initialization routine. + +This enumeration/discovery method can be started only once and does not support +unloading if it is built as a module. The enumeration process traverses the network using a recursive depth-first algorithm. When a new device is found, the enumerator takes ownership of that @@ -160,6 +253,19 @@ time period. If this wait time period expires before enumeration is completed, an agent skips RapidIO discovery and continues with remaining kernel initialization. +4.5 Adding New Enumeration/Discovery Method +------------------------------------------- + +RapidIO subsystem code organization allows addition of new enumeration/discovery +methods as new configuration options without significant impact to to the core +RapidIO code. + +A new enumeration/discovery method has to be attached to one or more mport +devices before an enumeration/discovery process can be started. Normally, +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 ------------- diff --git a/Documentation/rapidio/sysfs.txt b/Documentation/rapidio/sysfs.txt index 97f71ce575d6..19878179da4c 100644 --- a/Documentation/rapidio/sysfs.txt +++ b/Documentation/rapidio/sysfs.txt @@ -88,3 +88,20 @@ that exports additional attributes. IDT_GEN2: errlog - reads contents of device error log until it is empty. + + +5. RapidIO Bus Attributes +------------------------- + +RapidIO bus subdirectory /sys/bus/rapidio implements the following bus-specific +attribute: + + scan - allows to trigger enumeration discovery process from user space. This + is a write-only attribute. To initiate an enumeration or discovery + process on specific mport device, a user needs to write mport_ID (not + RapidIO destination ID) into this file. The mport_ID is a sequential + number (0 ... RIO_MAX_MPORTS) assigned to the mport device. + For example, for a machine with a single RapidIO controller, mport_ID + for that controller always will be 0. + To initiate RapidIO enumeration/discovery on all available mports + a user must write '-1' (or RIO_MPORT_ANY) into this attribute file. |