scsi: cxlflash: Support AFU debug

Adopt the SISLite AFU debug capability to allow future CXL Flash
adapters the ability to better debug AFU issues. Update the SISLite
header with the changes necessary to support AFU debug operations
and create a host ioctl interface for user debug 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, 14 insertions, 0 deletions

diff --git a/Documentation/powerpc/cxlflash.txt b/Documentation/powerpc/cxlflash.txt
index 2d6297b..a64bdaa 100644
--- a/Documentation/powerpc/cxlflash.txt
+++ b/Documentation/powerpc/cxlflash.txt
@@ -413,3 +413,17 @@ HT_CXLFLASH_LUN_PROVISION
 
     With this information, the number of available LUNs and capacity can be
     can be calculated.
+
+HT_CXLFLASH_AFU_DEBUG
+---------------------
+    This ioctl is used to debug AFUs by supporting a command pass-through
+    interface. It is only valid when used with AFUs that support the AFU
+    debug capability.
+
+    With exception of buffer management, AFU debug commands are opaque to
+    cxlflash and treated as pass-through. For debug commands that do require
+    data transfer, the user supplies an adequately sized data buffer and must
+    specify the data transfer direction with respect to the host. There is a
+    maximum transfer size of 256K imposed. Note that partial read completions
+    are not supported - when errors are experienced with a host read data
+    transfer, the data buffer is not copied back to the user.