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-rw-r--r--Documentation/powerpc/cxlflash.txt76
-rw-r--r--Documentation/powerpc/firmware-assisted-dump.txt4
2 files changed, 76 insertions, 4 deletions
diff --git a/Documentation/powerpc/cxlflash.txt b/Documentation/powerpc/cxlflash.txt
index 66b4496d6619..a64bdaa0a1cf 100644
--- a/Documentation/powerpc/cxlflash.txt
+++ b/Documentation/powerpc/cxlflash.txt
@@ -124,8 +124,8 @@ Block library API
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
@@ -257,6 +257,12 @@ DK_CXLFLASH_VLUN_RESIZE
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
@@ -309,6 +315,12 @@ DK_CXLFLASH_VLUN_CLONE
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
@@ -355,3 +367,63 @@ DK_CXLFLASH_MANAGE_LUN
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
+
+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.
+
+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.
diff --git a/Documentation/powerpc/firmware-assisted-dump.txt b/Documentation/powerpc/firmware-assisted-dump.txt
index 9cabaf8a207e..bdd344aa18d9 100644
--- a/Documentation/powerpc/firmware-assisted-dump.txt
+++ b/Documentation/powerpc/firmware-assisted-dump.txt
@@ -61,8 +61,8 @@ as follows:
boot successfully. For syntax of crashkernel= parameter,
refer to Documentation/kdump/kdump.txt. If any offset is
provided in crashkernel= parameter, it will be ignored
- as fadump reserves memory at end of RAM for boot memory
- dump preservation in case of a crash.
+ as fadump uses a predefined offset to reserve memory
+ for boot memory dump preservation in case of a crash.
-- After the low memory (boot memory) area has been saved, the
firmware will reset PCI and other hardware state. It will