rapidio: rework device hierarchy and introduce mport class of devices

This patch removes an artificial RapidIO bus root device and establishes
actual device hierarchy by providing reference to real parent devices.
It also introduces device class for RapidIO controller devices (on-chip
or an eternal bridge, known as "mport").

Existing implementation was sufficient for SoC-based platforms that have
a single RapidIO controller.  With introduction of devices using
multiple RapidIO controllers and PCIe-to-RapidIO bridges the old scheme
is very limiting or does not work at all.  The implemented changes allow
to properly reference platform's local RapidIO mport devices and provide
device details needed for upper layers.

This change to RapidIO device hierarchy does not break any known
existing kernel or user space interfaces.

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-technologies.com>
Cc: Stef van Os <stef.van.os@prodrive-technologies.com>
Cc: Jerry Jacobs <jerry.jacobs@prodrive-technologies.com>
Cc: Arno Tiemersma <arno.tiemersma@prodrive-technologies.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 58 insertions, 8 deletions

diff --git a/Documentation/rapidio/sysfs.txt b/Documentation/rapidio/sysfs.txt
index 271438c0617f..47ce9a5336e1 100644
--- a/Documentation/rapidio/sysfs.txt
+++ b/Documentation/rapidio/sysfs.txt
@@ -2,8 +2,8 @@
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-1. Device Subdirectories
-------------------------
+1. RapidIO Device Subdirectories
+--------------------------------
 
 For each RapidIO device, the RapidIO subsystem creates files in an individual
 subdirectory with the following name, /sys/bus/rapidio/devices/<device_name>.
@@ -25,8 +25,8 @@ seen by the enumerating host (destID = 1):
 NOTE: An enumerating or discovering endpoint does not create a sysfs entry for
 itself, this is why an endpoint with destID=1 is not shown in the list.
 
-2. Attributes Common for All Devices
-------------------------------------
+2. Attributes Common for All RapidIO Devices
+--------------------------------------------
 
 Each device subdirectory contains the following informational read-only files:
 
@@ -52,16 +52,16 @@ This attribute is similar in behavior to the "config" attribute of PCI devices
 and provides an access to the RapidIO device registers using standard file read
 and write operations.
 
-3. Endpoint Device Attributes
------------------------------
+3. RapidIO Endpoint Device Attributes
+-------------------------------------
 
 Currently Linux RapidIO subsystem does not create any endpoint specific sysfs
 attributes. It is possible that RapidIO master port drivers and endpoint device
 drivers will add their device-specific sysfs attributes but such attributes are
 outside the scope of this document.
 
-4. Switch Device Attributes
----------------------------
+4. RapidIO Switch Device Attributes
+-----------------------------------
 
 RapidIO switches have additional attributes in sysfs. RapidIO subsystem supports
 common and device-specific sysfs attributes for switches. Because switches are
@@ -106,3 +106,53 @@ attribute:
          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.
+
+
+6. RapidIO Bus Controllers/Ports
+--------------------------------
+
+On-chip RapidIO controllers and PCIe-to-RapidIO bridges (referenced as
+"Master Port" or "mport") are presented in sysfs as the special class of
+devices: "rapidio_port".
+
+The /sys/class/rapidio_port subdirectory contains individual subdirectories
+named as "rapidioN" where N = mport ID registered with RapidIO subsystem.
+
+NOTE: An mport ID is not a RapidIO destination ID assigned to a given local
+mport device.
+
+Each mport device subdirectory in addition to standard entries contains the
+following device-specific attributes:
+
+   port_destid - reports RapidIO destination ID assigned to the given RapidIO
+                 mport device. If value 0xFFFFFFFF is returned this means that
+                 no valid destination ID have been assigned to the mport (yet).
+                 Normally, before enumeration/discovery have been executed only
+                 fabric enumerating mports have a valid destination ID assigned
+                 to them using "hdid=..." rapidio module parameter.
+      sys_size - reports RapidIO common transport system size:
+                   0 = small (8-bit destination ID, max. 256 devices),
+                   1 = large (16-bit destination ID, max. 65536 devices).
+
+After enumeration or discovery was performed for a given mport device,
+the corresponding subdirectory will also contain subdirectories for each
+child RapidIO device connected to the mport. Naming conventions for RapidIO
+devices are described in Section 1 above.
+
+The example below shows mport device subdirectory with several child RapidIO
+devices attached to it.
+
+[rio@rapidio ~]$ ls /sys/class/rapidio_port/rapidio0/ -l
+total 0
+drwxr-xr-x 3 root root    0 Feb 11 15:10 00:e:0001
+drwxr-xr-x 3 root root    0 Feb 11 15:10 00:e:0004
+drwxr-xr-x 3 root root    0 Feb 11 15:10 00:e:0007
+drwxr-xr-x 3 root root    0 Feb 11 15:10 00:s:0002
+drwxr-xr-x 3 root root    0 Feb 11 15:10 00:s:0003
+drwxr-xr-x 3 root root    0 Feb 11 15:10 00:s:0005
+lrwxrwxrwx 1 root root    0 Feb 11 15:11 device -> ../../../0000:01:00.0
+-r--r--r-- 1 root root 4096 Feb 11 15:11 port_destid
+drwxr-xr-x 2 root root    0 Feb 11 15:11 power
+lrwxrwxrwx 1 root root    0 Feb 11 15:04 subsystem -> ../../../../../../class/rapidio_port
+-r--r--r-- 1 root root 4096 Feb 11 15:11 sys_size
+-rw-r--r-- 1 root root 4096 Feb 11 15:04 uevent