http://github.com/open-power/capiflash
-CXL Flash Driver IOCTLs
-=======================
+CXL Flash Driver LUN IOCTLs
+===========================
Users, such as the block library, that wish to interface with a flash
device (LUN) via user space access need to use the services provided
operating in the virtual mode and used to program a LUN translation
table that the AFU references when provided with a resource handle.
+ This ioctl can return -EAGAIN if an AFU sync operation takes too long.
+ In addition to returning a failure to user, cxlflash will also schedule
+ an asynchronous AFU reset. Should the user choose to retry the operation,
+ it is expected to succeed. If this ioctl fails with -EAGAIN, the user
+ can either retry the operation or treat it as a failure.
+
DK_CXLFLASH_RELEASE
-------------------
This ioctl is responsible for releasing a previously obtained
clone. This is to avoid a stale entry in the file descriptor table of the
child process.
+ This ioctl can return -EAGAIN if an AFU sync operation takes too long.
+ In addition to returning a failure to user, cxlflash will also schedule
+ an asynchronous AFU reset. Should the user choose to retry the operation,
+ it is expected to succeed. If this ioctl fails with -EAGAIN, the user
+ can either retry the operation or treat it as a failure.
+
DK_CXLFLASH_VERIFY
------------------
This ioctl is used to detect various changes such as the capacity of
exclusive user space access (superpipe). In case a LUN is visible
across multiple ports and adapters, this ioctl is used to uniquely
identify each LUN by its World Wide Node Name (WWNN).
+
+
+CXL Flash Driver Host IOCTLs
+============================
+
+ Each host adapter instance that is supported by the cxlflash driver
+ has a special character device associated with it to enable a set of
+ host management function. These character devices are hosted in a
+ class dedicated for cxlflash and can be accessed via /dev/cxlflash/*.
+
+ Applications can be written to perform various functions using the
+ host ioctl APIs below.
+
+ The structure definitions for these IOCTLs are available in:
+ uapi/scsi/cxlflash_ioctl.h