RE: [PATCH] Documentation: rapidio: move sysfs interface to ABI

From: Bounine, Alexandre
Date: Wed Jan 17 2018 - 11:16:41 EST


For users convenience and due to limited use of RapidIO I would prefer to keep all subsystem documentation in one place.
Also, having text file in free format gives us ability to easily add explanations and examples which we cannot have
in ABI documentation format.

If converting this file into ABI doc is absolutely necessary:
- please keep the original sysfs.txt with a single statement that directs reader to the ABI docs.
- see comments below

On Tuesday, Jan 9, 2018 at 6:21 AM, Aishwarya Pant wrote:
> Subject: [PATCH] Documentation: rapidio: move sysfs interface to ABI
>
> Right now, the description of the rapidio sysfs interfaces is in
> Documentation/rapidio/sysfs.txt. Since these are a part of the ABI, they
> should be in Documentation/ABI along with the rest.
>
> Signed-off-by: Aishwarya Pant <aishpant@xxxxxxxxx>
> ---
> Documentation/ABI/testing/sysfs-bus-rapidio | 183
> ++++++++++++++++++++++++++
> Documentation/ABI/testing/sysfs-class-rapidio | 55 ++++++++
> Documentation/rapidio/sysfs.txt | 158 ----------------------
> 3 files changed, 238 insertions(+), 158 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-rapidio
> create mode 100644 Documentation/ABI/testing/sysfs-class-rapidio
> delete mode 100644 Documentation/rapidio/sysfs.txt
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-rapidio
> b/Documentation/ABI/testing/sysfs-bus-rapidio
> new file mode 100644
> index 000000000000..9b755776c1ab
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-rapidio
> @@ -0,0 +1,183 @@
> +What: /sys/bus/rapidio/devices/00:e:0000
> +What: /sys/bus/rapidio/devices/00:e:0002
> +What: /sys/bus/rapidio/devices/00:s:0001
> +Description:
> + For each RapidIO device, the RapidIO subsystem creates files
> in
> + an individual subdirectory with the following name format of
> + device_name "nn:d:iiii", where:
> +
> + nn - two-digit hexadecimal ID of RapidIO network where the
> + device resides
> + d - device typr: 'e' - for endpoint or 's' - for switch

Typo here

> + iiii - four-digit device destID for endpoints, or switchID for
> + switches
> +
> + 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.
> +

The note above used without explanatory context changes the idea: it sounds like enumerator's destID is always 1.

> +Attributes Common for All RapidIO Devices
> +-----------------------------------------
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/did
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns the device identifier
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/vid
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns the device vendor identifier
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/device_rev
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns the device revision level
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/asm_did
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns identifier for the assembly containing the device
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/asm_rev
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns revision level of the assembly containing the
> + device
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/asm_vid
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns vendor identifier of the assembly containing the
> + device
> +

The "destid" attribute must be here: it is common for all RapidIO devices. Must be note explaining a different role for switches.

> +What: /sys/bus/rapidio/devices/nn:d:iiii/lprev
> +Date: Mar, 2011
> +KernelVersion: v2.6.39
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns name of previous device (switch) on the path to
> the
> + device that that owns this attribute
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/modalias
> +Date: Jul, 2013
> +KernelVersion: v3.11
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns the device modalias
> +
> +What: /sys/bus/rapidio/devices/nn:d:iiii/config
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RW) reads from and writes to the device configuration
> + registers. Each rapidio device has a binary attribute file that
> + allows read/write access to the device configuration registers
> + using the RapidIO maintenance transactions. 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.
> +
Edited description:
(RW) Binary attribute to read from and write to the device configuration
Registers using the RapidIO maintenance transactions. 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.

> +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
> +integrated into the RapidIO subsystem, it offers a method to create
> +device-specific sysfs attributes by specifying a callback function that may be
> +set by the switch initialization routine during enumeration or discovery
> +process.
> +
> +What: /sys/bus/rapidio/devices/nn:s:iiii/routes
> +Date: Nov, 2005
> +KernelVersion: v2.6.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) reports switch routing information in "destID port"
> format.
> + This attribute reports only valid routing table entries, one
> + line for each entry. number of hops on the path to the switch
> +

"number of hops on the path to the switch" is not from there. See "hopcount" below.

> +What: /sys/bus/rapidio/devices/nn:d:iiii/destid
> +Date: Mar, 2011
> +KernelVersion: v2.6.3
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns device destination ID assigned by the
> enumeration
> + routine
> +

The "destid" attribute should be described where marked above. Just make a note that for switches it identifies a route
by reporting destid of an associated device.

> +What: /sys/bus/rapidio/devices/nn:s:iiii/hopcount
> +Date: Mar, 2011
> +KernelVersion: v2.6.39
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) number of hops on the path to the switch
> +
> +What: /sys/bus/rapidio/devices/nn:s:iiii/lnext
> +Date: Mar, 2011
> +KernelVersion: v2.6.39
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) returns names of devices linked to the switch except
> one of
> + a device linked to the ingress port (reported as "lprev"). This
> + is an array names with number of lines equal to number of
> ports
> + in switch. If a switch port has no attached device, returns
> + "null" instead of a device name.
> +
> +Device-specific Switch Attributes
> +---------------------------------
> +
> +IDT_GEN2-
> +
> +What: /sys/bus/rapidio/devices/nn:s:iiii/errlog
> +Date: Oct, 2010
> +KernelVersion: v2.6.37
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) reads contents of device error log until it is empty.
> +
> +RapidIO Bus Attributes
> +----------------------
> +
> +What: /sys/bus/rapidio/scan
> +Date: May, 2013
> +KernelVersion: v3.11
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (WO) Allows to trigger enumeration discovery process from
> user
> + space. 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.
> diff --git a/Documentation/ABI/testing/sysfs-class-rapidio
> b/Documentation/ABI/testing/sysfs-class-rapidio
> new file mode 100644
> index 000000000000..bc867ac758ce
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-rapidio
> @@ -0,0 +1,55 @@
> +What: /sys/class/rapidio_port
> +Description:
> + 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.
> +
> +What: /sys/class/rapidio_port/rapidioN/sys_size
> +Date: Apr, 2014
> +KernelVersion: v3.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) reports RapidIO common transport system size:
> + 0 = small (8-bit destination ID, max. 256 devices),
> + 1 = large (16-bit destination ID, max. 65536 devices).
> +
> +What: /sys/class/rapidio_port/rapidioN/port_destid
> +Date: Apr, 2014
> +KernelVersion: v3.15
> +Contact: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>,
> + Alexandre Bounine <alexandre.bounine@xxxxxxx>
> +Description:
> + (RO) 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.
> +
> +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.
> +
> +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
> diff --git a/Documentation/rapidio/sysfs.txt
> b/Documentation/rapidio/sysfs.txt
> deleted file mode 100644
> index 47ce9a5336e1..000000000000
> --- a/Documentation/rapidio/sysfs.txt
> +++ /dev/null
> @@ -1,158 +0,0 @@
> - RapidIO sysfs Files
> -
> -
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ~~~~~~~~~~~~~~~~~~~~~~
> -
> -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>.
> -
> -The format of device_name is "nn:d:iiii", where:
> -
> -nn - two-digit hexadecimal ID of RapidIO network where the device resides
> -d - device typr: 'e' - for endpoint or 's' - for switch
> -iiii - four-digit device destID for endpoints, or switchID for switches
> -
> -For example, below is a list of device directories that represents a typical
> -RapidIO network with one switch, one host, and two agent endpoints, as it
> is
> -seen by the enumerating host (destID = 1):
> -
> -/sys/bus/rapidio/devices/00:e:0000
> -/sys/bus/rapidio/devices/00:e:0002
> -/sys/bus/rapidio/devices/00:s:0001
> -
> -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 RapidIO Devices
> ---------------------------------------------
> -
> -Each device subdirectory contains the following informational read-only
> files:
> -
> - did - returns the device identifier
> - vid - returns the device vendor identifier
> -device_rev - returns the device revision level
> - asm_did - returns identifier for the assembly containing the device
> - asm_rev - returns revision level of the assembly containing the device
> - asm_vid - returns vendor identifier of the assembly containing the device
> - destid - returns device destination ID assigned by the enumeration
> routine
> - (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
> -the RapidIO maintenance transactions:
> -
> - config - reads from and writes to the device configuration registers.
> -
> -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. 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. 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
> -integrated into the RapidIO subsystem, it offers a method to create
> -device-specific sysfs attributes by specifying a callback function that may be
> -set by the switch initialization routine during enumeration or discovery
> process.
> -
> -4.1 Common Switch Attributes
> -
> - routes - reports switch routing information in "destID port" format. This
> - attribute reports only valid routing table entries, one line for
> - each entry.
> - destid - device destination ID that defines a route to the switch
> - hopcount - number of hops on the path to the switch
> - lnext - returns names of devices linked to the switch except one of a
> device
> - linked to the ingress port (reported as "lprev"). This is an array
> - names with number of lines equal to number of ports in switch. If
> - a switch port has no attached device, returns "null" instead of
> - a device name.
> -
> -4.2 Device-specific Switch Attributes
> -
> -Device-specific switch attributes are listed for each RapidIO switch driver
> -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.
> -
> -
> -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
> --
> 2.15.1