path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-24 18:12:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-24 18:12:15 -0700
commit9cf1848278a41f8d5f69b26bca546cfd2d5677d8 (patch)
tree2628cd3e8e3ca1acfe81e636b082c285d97640d9 /Documentation
parent00cec111ac477ba71c99043358f17e9bb4d335fe (diff)
parent03e04f048d2774aabd126fbad84729d4ba9dc40a (diff)
Merge branch 'akpm' (incoming from Andrew Morton)
Merge fixes from Andrew Morton: "A bunch of fixes and one simple fbdev driver which missed the merge window because people will still talking about it (to no great effect)." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (30 commits) aio: fix kioctx not being freed after cancellation at exit time mm/pagewalk.c: walk_page_range should avoid VM_PFNMAP areas drivers/rtc/rtc-max8998.c: check for pdata presence before dereferencing ocfs2: goto out_unlock if ocfs2_get_clusters_nocache() failed in ocfs2_fiemap() random: fix accounting race condition with lockless irq entropy_count update drivers/char/random.c: fix priming of last_data mm/memory_hotplug.c: fix printk format warnings nilfs2: fix issue of nilfs_set_page_dirty() for page at EOF boundary drivers/block/brd.c: fix brd_lookup_page() race fbdev: FB_GOLDFISH should depend on HAS_DMA drivers/rtc/rtc-pl031.c: pass correct pointer to free_irq() auditfilter.c: fix kernel-doc warnings aio: fix io_getevents documentation revert "selftest: add simple test for soft-dirty bit" drivers/leds/leds-ot200.c: fix error caused by shifted mask mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer linux/kernel.h: fix kernel-doc warning mm compaction: fix of improper cache flush in migration code rapidio/tsi721: fix bug in MSI interrupt handling hfs: avoid crash in hfs_bnode_create ...
Diffstat (limited to 'Documentation')
3 files changed, 159 insertions, 11 deletions
diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt
new file mode 100644
index 00000000000..3ea46058311
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt
@@ -0,0 +1,25 @@
+Simple Framebuffer
+A simple frame-buffer describes a raw memory region that may be rendered to,
+with the assumption that the display hardware has already been set up to scan
+out from that buffer.
+Required properties:
+- compatible: "simple-framebuffer"
+- reg: Should contain the location and size of the framebuffer memory.
+- width: The width of the framebuffer in pixels.
+- height: The height of the framebuffer in pixels.
+- stride: The number of bytes in each line of the framebuffer.
+- format: The format of the framebuffer surface. Valid values are:
+ - r5g6b5 (16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b).
+ framebuffer {
+ compatible = "simple-framebuffer";
+ reg = <0x1d385000 (1600 * 1200 * 2)>;
+ width = <1600>;
+ height = <1200>;
+ stride = <(1600 * 2)>;
+ format = "r5g6b5";
+ };
diff --git a/Documentation/rapidio/rapidio.txt b/Documentation/rapidio/rapidio.txt
index c75694b35d0..a9c16c979da 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
+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 97f71ce575d..19878179da4 100644
--- a/Documentation/rapidio/sysfs.txt
+++ b/Documentation/rapidio/sysfs.txt
@@ -88,3 +88,20 @@ that exports additional attributes.
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
+ 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.