mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-25 04:41:15 +07:00
4a6ff3c9a6
Clarify the intention that interfaces and upper layers use regions rather than managers directly. Rearrange API documentation to better group the API functions used to create FPGA mgr/bridge/regions and the API used for programming FPGAs. Signed-off-by: Alan Tull <atull@kernel.org> Suggested-by: Federico Vaga <federico.vaga@cern.ch> Acked-by: Moritz Fischer <mdf@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
104 lines
3.7 KiB
ReStructuredText
104 lines
3.7 KiB
ReStructuredText
FPGA Region
|
|
===========
|
|
|
|
Overview
|
|
--------
|
|
|
|
This document is meant to be a brief overview of the FPGA region API usage. A
|
|
more conceptual look at regions can be found in the Device Tree binding
|
|
document [#f1]_.
|
|
|
|
For the purposes of this API document, let's just say that a region associates
|
|
an FPGA Manager and a bridge (or bridges) with a reprogrammable region of an
|
|
FPGA or the whole FPGA. The API provides a way to register a region and to
|
|
program a region.
|
|
|
|
Currently the only layer above fpga-region.c in the kernel is the Device Tree
|
|
support (of-fpga-region.c) described in [#f1]_. The DT support layer uses regions
|
|
to program the FPGA and then DT to handle enumeration. The common region code
|
|
is intended to be used by other schemes that have other ways of accomplishing
|
|
enumeration after programming.
|
|
|
|
An fpga-region can be set up to know the following things:
|
|
|
|
* which FPGA manager to use to do the programming
|
|
|
|
* which bridges to disable before programming and enable afterwards.
|
|
|
|
Additional info needed to program the FPGA image is passed in the struct
|
|
fpga_image_info including:
|
|
|
|
* pointers to the image as either a scatter-gather buffer, a contiguous
|
|
buffer, or the name of firmware file
|
|
|
|
* flags indicating specifics such as whether the image is for partial
|
|
reconfiguration.
|
|
|
|
How to add a new FPGA region
|
|
----------------------------
|
|
|
|
An example of usage can be seen in the probe function of [#f2]_.
|
|
|
|
.. [#f1] ../devicetree/bindings/fpga/fpga-region.txt
|
|
.. [#f2] ../../drivers/fpga/of-fpga-region.c
|
|
|
|
API to add a new FPGA region
|
|
----------------------------
|
|
|
|
* struct :c:type:`fpga_region` — The FPGA region struct
|
|
* :c:func:`devm_fpga_region_create` — Allocate and init a region struct
|
|
* :c:func:`fpga_region_register` — Register an FPGA region
|
|
* :c:func:`fpga_region_unregister` — Unregister an FPGA region
|
|
|
|
The FPGA region's probe function will need to get a reference to the FPGA
|
|
Manager it will be using to do the programming. This usually would happen
|
|
during the region's probe function.
|
|
|
|
* :c:func:`fpga_mgr_get` — Get a reference to an FPGA manager, raise ref count
|
|
* :c:func:`of_fpga_mgr_get` — Get a reference to an FPGA manager, raise ref count,
|
|
given a device node.
|
|
* :c:func:`fpga_mgr_put` — Put an FPGA manager
|
|
|
|
The FPGA region will need to specify which bridges to control while programming
|
|
the FPGA. The region driver can build a list of bridges during probe time
|
|
(:c:member:`fpga_region->bridge_list`) or it can have a function that creates
|
|
the list of bridges to program just before programming
|
|
(:c:member:`fpga_region->get_bridges`). The FPGA bridge framework supplies the
|
|
following APIs to handle building or tearing down that list.
|
|
|
|
* :c:func:`fpga_bridge_get_to_list` — Get a ref of an FPGA bridge, add it to a
|
|
list
|
|
* :c:func:`of_fpga_bridge_get_to_list` — Get a ref of an FPGA bridge, add it to a
|
|
list, given a device node
|
|
* :c:func:`fpga_bridges_put` — Given a list of bridges, put them
|
|
|
|
.. kernel-doc:: include/linux/fpga/fpga-region.h
|
|
:functions: fpga_region
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-region.c
|
|
:functions: devm_fpga_region_create
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-region.c
|
|
:functions: fpga_region_register
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-region.c
|
|
:functions: fpga_region_unregister
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-mgr.c
|
|
:functions: fpga_mgr_get
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-mgr.c
|
|
:functions: of_fpga_mgr_get
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-mgr.c
|
|
:functions: fpga_mgr_put
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-bridge.c
|
|
:functions: fpga_bridge_get_to_list
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-bridge.c
|
|
:functions: of_fpga_bridge_get_to_list
|
|
|
|
.. kernel-doc:: drivers/fpga/fpga-bridge.c
|
|
:functions: fpga_bridges_put
|