[PATCH v8 1/4] Documentation: fpga: dfl: Add documentation for DFHv1

[matthew.gerlach@linux.intel.com]

From: Matthew Gerlach <matthew.gerlach@linux.intel.com>

Add documentation describing the extensions provided by Version
1 of the Device Feature Header (DFHv1).

Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
v8: fix section titles

v7: shorten long lines and wording suggestions by bagasdotme@gmail.com

v6: no change

v5: use nested list for field descriptions
    clean up prose
    add reviewed-by and comments from Ilpo Järvinen

v4: Remove marketing speak and separate v0 and v1 descriptions.
    Fix errors reported by "make htmldocs".

v3: no change

v2: s/GUILD/GUID/
    add picture
---
 Documentation/fpga/dfl.rst | 112 +++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)

diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst
index 15b670926084..264b476fc6ac 100644
--- a/Documentation/fpga/dfl.rst
+++ b/Documentation/fpga/dfl.rst
@@ -561,6 +561,118 @@ new DFL feature via UIO direct access, its feature id should be added to the
 driver's id_table.
 
 
+Device Feature Header - Version 0
+=================================
+Version 0 (DFHv0) is the original version of the Device Feature Header.
+The format of DFHv0 is shown below::
+
+    +-----------------------------------------------------------------------+
+    |63 Type 60|59 DFH VER 52|51 Rsvd 41|40 EOL|39 Next 16|15 VER 12|11 ID 0| 0x00
+    +-----------------------------------------------------------------------+
+    |63                                 GUID_L                             0| 0x08
+    +-----------------------------------------------------------------------+
+    |63                                 GUID_H                             0| 0x10
+    +-----------------------------------------------------------------------+
+
+- Offset 0x00
+
+  * Type - The type of DFH (e.g. FME, AFU, or private feature).
+  * DFH VER - The version of the DFH.
+  * Rsvd - Currently unused.
+  * EOL - Set if the DFH is the end of the Device Feature List (DFL).
+  * Next - The offset of the next DFH in the DFL from the DFH start.
+    If EOL is set, Next is the size of MMIO of the last feature in the list.
+  * ID - The feature ID if Type is private feature.
+
+- Offset 0x08
+
+  * GUID_L - Least significant 64 bits of a 128-bit Globally Unique Identifier
+    (present only if Type is FME or AFU).
+
+- Offset 0x10
+
+  * GUID_H - Most significant 64 bits of a 128-bit Globally Unique Identifier
+    (present only if Type is FME or AFU).
+
+
+Device Feature Header - Version 1
+=================================
+Version 1 (DFHv1) of the Device Feature Header adds the following functionality:
+
+* Provides a standardized mechanism for features to describe
+  parameters/capabilities to software.
+* Standardize the use of a GUID for all DFHv1 types.
+* Decouples the DFH location from the register space of the feature itself.
+
+The format of Version 1 of the Device Feature Header (DFH) is shown below::
+
+    +-----------------------------------------------------------------------+
+    |63 Type 60|59 DFH VER 52|51 Rsvd 41|40 EOL|39 Next 16|15 VER 12|11 ID 0| 0x00
+    +-----------------------------------------------------------------------+
+    |63                                 GUID_L                             0| 0x08
+    +-----------------------------------------------------------------------+
+    |63                                 GUID_H                             0| 0x10
+    +-----------------------------------------------------------------------+
+    |63                   Reg Address/Offset                      1|  Rel  0| 0x18
+    +-----------------------------------------------------------------------+
+    |63        Reg Size       32|Params 31|30 Group    16|15 Instance      0| 0x20
+    +-----------------------------------------------------------------------+
+    |63 Next    35|34RSV33|EOP32|31 Param Version 16|15 Param ID           0| 0x28
+    +-----------------------------------------------------------------------+
+    |63                 Parameter Data                                     0| 0x30
+    +-----------------------------------------------------------------------+
+
+                                  ...
+
+    +-----------------------------------------------------------------------+
+    |63 Next    35|34RSV33|EOP32|31 Param Version 16|15 Param ID           0|
+    +-----------------------------------------------------------------------+
+    |63                 Parameter Data                                     0|
+    +-----------------------------------------------------------------------+
+
+- Offset 0x00
+
+  * Type - The type of DFH (e.g. FME, AFU, or private feature).
+  * DFH VER - The version of the DFH.
+  * Rsvd - Currently unused.
+  * EOL - Set if the DFH is the end of the Device Feature List (DFL).
+  * Next - The offset of the next DFH in the DFL from the DFH start.
+    If EOL is set, Next is the size of MMIO of the last feature in the list.
+  * ID - The feature ID if Type is private feature.
+
+- Offset 0x08
+
+  * GUID_L - Least significant 64 bits of a 128-bit Globally Unique Identifier.
+
+- Offset 0x10
+
+  * GUID_H - Most significant 64 bits of a 128-bit Globally Unique Identifier.
+
+- Offset 0x18
+
+  * Reg Address/Offset - If Rel bit is set, then the value is the high 63 bits
+    of a 16-bit aligned absolute address of the feature's registers. Otherwise
+    the value is the offset from the start of the DFH of the feature's registers.
+
+- Offset 0x20
+
+  * Reg Size - Size of feature's register set in bytes.
+  * Params - Set if DFH has a list of parameter blocks.
+  * Group - Id of group if feature is part of a group.
+  * Instance - Id of feature instance within a group.
+
+- Offset 0x28 if feature has parameters
+
+  * Next - Offset to the next parameter block in 8 byte words. If EOP set,
+    size in 8 byte words of last parameter.
+  * Param Version - Version of Param ID.
+  * Param ID - ID of parameter.
+
+- Offset 0x30
+
+  * Parameter Data - Parameter data whose size and format is defined by
+    version and ID of the parameter.
+
 Open discussion
 ===============
 FME driver exports one ioctl (DFL_FPGA_FME_PORT_PR) for partial reconfiguration
-- 
2.25.1