scsi: cxlflash: Support LUN provisioning

Adopt the SISLite AFU LUN provisioning capability to allow future CXL
Flash adapters the ability to better manage storage. Update the SISLite
header with the changes necessary to support LUN provision operations
and create a host ioctl interface for user LUN management software. Also
update the cxlflash documentation to describe this new host ioctl.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/Documentation/powerpc/cxlflash.txt b/Documentation/powerpc/cxlflash.txt
index ee67021..2d6297b 100644
--- a/Documentation/powerpc/cxlflash.txt
+++ b/Documentation/powerpc/cxlflash.txt
@@ -382,3 +382,34 @@ CXL Flash Driver Host IOCTLs
 
     The structure definitions for these IOCTLs are available in:
     uapi/scsi/cxlflash_ioctl.h
+
+HT_CXLFLASH_LUN_PROVISION
+-------------------------
+    This ioctl is used to create and delete persistent LUNs on cxlflash
+    devices that lack an external LUN management interface. It is only
+    valid when used with AFUs that support the LUN provision capability.
+
+    When sufficient space is available, LUNs can be created by specifying
+    the target port to host the LUN and a desired size in 4K blocks. Upon
+    success, the LUN ID and WWID of the created LUN will be returned and
+    the SCSI bus can be scanned to detect the change in LUN topology. Note
+    that partial allocations are not supported. Should a creation fail due
+    to a space issue, the target port can be queried for its current LUN
+    geometry.
+
+    To remove a LUN, the device must first be disassociated from the Linux
+    SCSI subsystem. The LUN deletion can then be initiated by specifying a
+    target port and LUN ID. Upon success, the LUN geometry associated with
+    the port will be updated to reflect new number of provisioned LUNs and
+    available capacity.
+
+    To query the LUN geometry of a port, the target port is specified and
+    upon success, the following information is presented:
+
+        - Maximum number of provisioned LUNs allowed for the port
+        - Current number of provisioned LUNs for the port
+        - Maximum total capacity of provisioned LUNs for the port (4K blocks)
+        - Current total capacity of provisioned LUNs for the port (4K blocks)
+
+    With this information, the number of available LUNs and capacity can be
+    can be calculated.