[PATCH v2 4/5] x86/platform/uv: Update ABI documentation of /sys/firmware/sgi_uv/

[Justin Ernst <justin.ernst@hpe.com>]

Update the ABI documentation to describe the sysfs interface provided by
the new uv_sysfs platform driver.

Signed-off-by: Justin Ernst <justin.ernst@hpe.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
---
 .../ABI/testing/sysfs-firmware-sgi_uv         | 141 ++++++++++++++++--
 1 file changed, 127 insertions(+), 14 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-firmware-sgi_uv b/Documentation/ABI/testing/sysfs-firmware-sgi_uv
index 66800baab096..50e25ce80fa2 100644
--- a/Documentation/ABI/testing/sysfs-firmware-sgi_uv
+++ b/Documentation/ABI/testing/sysfs-firmware-sgi_uv
@@ -1,27 +1,140 @@
 What:		/sys/firmware/sgi_uv/
-Date:		August 2008
-Contact:	Russ Anderson <rja@sgi.com>
+Date:		September 2020
+Contact:	Justin Ernst <justin.ernst@hpe.com>
 Description:
 		The /sys/firmware/sgi_uv directory contains information
-		about the SGI UV platform.
+		about the UV platform.
 
-		Under that directory are a number of files::
+		Under that directory are a number of read-only attributes:
 
 			partition_id
 			coherence_id
+			uv_type
 
 		The partition_id entry contains the partition id.
-		SGI UV systems can be partitioned into multiple physical
+		UV systems can be partitioned into multiple physical
 		machines, which each partition running a unique copy
-		of the operating system.  Each partition will have a unique
-		partition id.  To display the partition id, use the command::
-
-			cat /sys/firmware/sgi_uv/partition_id
+		of the operating system. Each partition will have a unique
+		partition id.
 
 		The coherence_id entry contains the coherence id.
-		A partitioned SGI UV system can have one or more coherence
-		domain.  The coherence id indicates which coherence domain
-		this partition is in.  To display the coherence id, use the
-		command::
+		A partitioned UV system can have one or more coherence
+		domains. The coherence id indicates which coherence domain
+		this partition is in.
+
+		The uv_type entry contains the hub revision number.
+		This value can be used to identify the UV system version:
+			"3.0" = UV2
+			"5.0" = UV3
+			"7.0" = UV4
+			"7.1" = UV4a
+			"9.0" = UV5
+
+		The /sys/firmware/sgi_uv directory also contains two directories:
+
+			hubs/
+			pcibuses/
+
+		The hubs directory contains a number of hub objects, each representing
+		a UV Hub visible to the BIOS. Each hub object's name is appended by a
+		unique ordinal value (ex. /sys/firmware/sgi_uv/hubs/hub_5)
+
+		Each hub object directory contains a number of read-only attributes:
+
+			cnode
+			location
+			name
+			nasid
+			shared
+			this_partition
+
+		The cnode entry contains the cnode number of the corresponding hub.
+		If a cnode value is not applicable, the value returned will be -1.
+
+		The location entry contains the location string of the corresponding hub.
+		This value is used to physically identify a hub within a system.
+
+		The name entry contains the name of the corresponding hub. This name can
+		be two variants:
+			"UVHub x.x" = A 'node' ASIC, connecting a CPU to the interconnect
+				fabric. The 'x.x' value represents the ASIC revision.
+				(ex. 'UVHub 5.0')
+			"NLxRouter" = A 'router ASIC, only connecting other ASICs to
+				the interconnect fabric. The 'x' value representing
+				the fabric technology version. (ex. 'NL8Router')
+
+		The nasid entry contains the nasid number of the corresponding hub.
+		If a nasid value is not applicable, the value returned will be -1.
+
+		The shared entry contains a boolean value describing whether the
+		corresponding hub is shared between system partitions.
+
+		The this_partition entry contains a boolean value describing whether
+		the corresponding hub is local to the current partition.
+
+		Each hub object directory also contains a number of port objects,
+		each representing a fabric port on the corresponding hub.
+		A port object's name is appended by a unique ordinal value
+		(ex. /sys/firmware/sgi_uv/hubs/hub_5/port_3)
+
+		Each port object directory contains a number of read-only attributes:
+
+			conn_hub
+			conn_port
+
+		The conn_hub entry contains a value representing the unique
+		oridinal value of the hub on the other end of the fabric
+		cable plugged into the port. If the port is disconnected,
+		the value returned will be -1.
+
+		The conn_port entry contains a value representing the unique
+		oridinal value of the port on the other end of the fabric cable
+		plugged into the port. If the port is disconnected, the value
+		returned will be -1.
+
+		Ex:
+			A value of '3' is read from:
+				/sys/firmware/sgi_uv/hubs/hub_5/port_3/conn_hub
+
+			and a value of '6' is read from:
+				/sys/firmware/sgi_uv/hubs/hub_5/port_3/conn_port
+
+			representing that this port is connected to:
+			/sys/firmware/sgi_uv/hubs/hub_3/port_6
+
+
+		The pcibuses directory contains a number of PCI bus objects.
+		Each PCI bus object's name is appended by its PCI bus address.
+		(ex. pcibus_0003:80)
+
+		Each pcibus object has a number of possible read-only attributes:
+
+			type
+			location
+			slot
+			ppb_addr
+			iio_stack
+
+		The type entry contains a value describing the type of IO at
+		the corresponding PCI bus address. Known possible values
+		across all UV versions are:
+			BASE IO
+			PCIe IO
+			PCIe SLOT
+			NODE IO
+			Riser
+			PPB
+
+		The location entry contains the location string of the UV Hub
+		of the CPU physically connected to the corresponding PCI bus.
+
+		The slot entry contains the physical slot number of the
+		corresponding PCI bus. This value is used to physically locate
+		PCI cards within a system.
+
+		The ppb_addr entry contains the PCI address string of the
+		bridged PCI bus. This entry is only present when the PCI bus
+		object type is 'PPB'.
 
-			cat /sys/firmware/sgi_uv/coherence_id
+		The iio_stack entry contains a value describing the IIO stack
+		number that the corresponding PCI bus object is connected to.
-- 
2.26.2