cxl/Documentation: List attribute permissions

Clarify the access permission of CXL sysfs attributes in the
documentation to help development of userspace tooling.
Reported-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/165603881198.551046.12893348287451903699.stgit@dwillia2-xfhSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Documentation/ABI/testing/sysfs-bus-cxl

@@ -57,28 +57,28 @@ Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL device objects export the devtype attribute which mirrors
-		the same value communicated in the DEVTYPE environment variable
-		for uevents for devices on the "cxl" bus.
+		(RO) CXL device objects export the devtype attribute which
+		mirrors the same value communicated in the DEVTYPE environment
+		variable for uevents for devices on the "cxl" bus.
 
 What:		/sys/bus/cxl/devices/*/modalias
 Date:		December, 2021
 KernelVersion:	v5.18
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL device objects export the modalias attribute which mirrors
-		the same value communicated in the MODALIAS environment variable
-		for uevents for devices on the "cxl" bus.
+		(RO) CXL device objects export the modalias attribute which
+		mirrors the same value communicated in the MODALIAS environment
+		variable for uevents for devices on the "cxl" bus.
 
 What:		/sys/bus/cxl/devices/portX/uport
 Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL port objects are enumerated from either a platform firmware
-		device (ACPI0017 and ACPI0016) or PCIe switch upstream port with
-		CXL component registers. The 'uport' symlink connects the CXL
-		portX object to the device that published the CXL port
+		(RO) CXL port objects are enumerated from either a platform
+		firmware device (ACPI0017 and ACPI0016) or PCIe switch upstream
+		port with CXL component registers. The 'uport' symlink connects
+		the CXL portX object to the device that published the CXL port
 		capability.
 
 What:		/sys/bus/cxl/devices/portX/dportY
@@ -86,20 +86,20 @@ Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL port objects are enumerated from either a platform firmware
-		device (ACPI0017 and ACPI0016) or PCIe switch upstream port with
-		CXL component registers. The 'dportY' symlink identifies one or
-		more downstream ports that the upstream port may target in its
-		decode of CXL memory resources.  The 'Y' integer reflects the
-		hardware port unique-id used in the hardware decoder target
-		list.
+		(RO) CXL port objects are enumerated from either a platform
+		firmware device (ACPI0017 and ACPI0016) or PCIe switch upstream
+		port with CXL component registers. The 'dportY' symlink
+		identifies one or more downstream ports that the upstream port
+		may target in its decode of CXL memory resources.  The 'Y'
+		integer reflects the hardware port unique-id used in the
+		hardware decoder target list.
 
 What:		/sys/bus/cxl/devices/decoderX.Y
 Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL decoder objects are enumerated from either a platform
+		(RO) CXL decoder objects are enumerated from either a platform
 		firmware description, or a CXL HDM decoder register set in a
 		PCIe device (see CXL 2.0 section 8.2.5.12 CXL HDM Decoder
 		Capability Structure). The 'X' in decoderX.Y represents the
@@ -111,42 +111,43 @@ Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		The 'start' and 'size' attributes together convey the physical
-		address base and number of bytes mapped in the decoder's decode
-		window. For decoders of devtype "cxl_decoder_root" the address
-		range is fixed. For decoders of devtype "cxl_decoder_switch" the
-		address is bounded by the decode range of the cxl_port ancestor
-		of the decoder's cxl_port, and dynamically updates based on the
-		active memory regions in that address space.
+		(RO) The 'start' and 'size' attributes together convey the
+		physical address base and number of bytes mapped in the
+		decoder's decode window. For decoders of devtype
+		"cxl_decoder_root" the address range is fixed. For decoders of
+		devtype "cxl_decoder_switch" the address is bounded by the
+		decode range of the cxl_port ancestor of the decoder's cxl_port,
+		and dynamically updates based on the active memory regions in
+		that address space.
 
 What:		/sys/bus/cxl/devices/decoderX.Y/locked
 Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		CXL HDM decoders have the capability to lock the configuration
-		until the next device reset. For decoders of devtype
-		"cxl_decoder_root" there is no standard facility to unlock them.
-		For decoders of devtype "cxl_decoder_switch" a secondary bus
-		reset, of the PCIe bridge that provides the bus for this
-		decoders uport, unlocks / resets the decoder.
+		(RO) CXL HDM decoders have the capability to lock the
+		configuration until the next device reset. For decoders of
+		devtype "cxl_decoder_root" there is no standard facility to
+		unlock them.  For decoders of devtype "cxl_decoder_switch" a
+		secondary bus reset, of the PCIe bridge that provides the bus
+		for this decoders uport, unlocks / resets the decoder.
 
 What:		/sys/bus/cxl/devices/decoderX.Y/target_list
 Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		Display a comma separated list of the current decoder target
-		configuration. The list is ordered by the current configured
-		interleave order of the decoder's dport instances. Each entry in
-		the list is a dport id.
+		(RO) Display a comma separated list of the current decoder
+		target configuration. The list is ordered by the current
+		configured interleave order of the decoder's dport instances.
+		Each entry in the list is a dport id.
 
 What:		/sys/bus/cxl/devices/decoderX.Y/cap_{pmem,ram,type2,type3}
 Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		When a CXL decoder is of devtype "cxl_decoder_root", it
+		(RO) When a CXL decoder is of devtype "cxl_decoder_root", it
 		represents a fixed memory window identified by platform
 		firmware. A fixed window may only support a subset of memory
 		types. The 'cap_*' attributes indicate whether persistent
@@ -158,8 +159,8 @@ Date:		June, 2021
 KernelVersion:	v5.14
 Contact:	linux-cxl@vger.kernel.org
 Description:
-		When a CXL decoder is of devtype "cxl_decoder_switch", it can
-		optionally decode either accelerator memory (type-2) or expander
-		memory (type-3). The 'target_type' attribute indicates the
-		current setting which may dynamically change based on what
+		(RO) When a CXL decoder is of devtype "cxl_decoder_switch", it
+		can optionally decode either accelerator memory (type-2) or
+		expander memory (type-3). The 'target_type' attribute indicates
+		the current setting which may dynamically change based on what
 		memory regions are activated in this decode hierarchy.