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author | Alan Tull <atull@kernel.org> | 2018-05-16 18:50:05 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-25 18:23:56 +0200 |
commit | fcc803956a4725dac790ddfce27f519ca6d84c60 (patch) | |
tree | 80d10c7389299ee557a63a908b05d83c0fb4b303 /Documentation | |
parent | 9e4c36b1c9799de406a183c0fe946a614d97288c (diff) | |
download | linux-stable-fcc803956a4725dac790ddfce27f519ca6d84c60.tar.gz linux-stable-fcc803956a4725dac790ddfce27f519ca6d84c60.tar.bz2 linux-stable-fcc803956a4725dac790ddfce27f519ca6d84c60.zip |
documentation: fpga: move fpga-region.txt to driver-api
Move Documentation/fpga/fpga-region.txt to
driver-api/fpga/fpga-region.rst. Including:
- Add it to driver-api/fpga/index.rst
- Formatting changes to build cleanly as ReST documentation
- Some rewrites for better flow as a ReST doc such as moving
API reference to the end of the doc
- Rewrite API reference section to refer to kernel-doc
documentation in fpga-region.c driver code
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/driver-api/fpga/fpga-region.rst | 102 | ||||
-rw-r--r-- | Documentation/driver-api/fpga/index.rst | 1 | ||||
-rw-r--r-- | Documentation/fpga/fpga-region.txt | 94 |
3 files changed, 103 insertions, 94 deletions
diff --git a/Documentation/driver-api/fpga/fpga-region.rst b/Documentation/driver-api/fpga/fpga-region.rst new file mode 100644 index 000000000000..f89e4a311722 --- /dev/null +++ b/Documentation/driver-api/fpga/fpga-region.rst @@ -0,0 +1,102 @@ +FPGA Region +=========== + +Overview +-------- + +This document is meant to be an 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 if for partial + reconfiguration. + +How to program a FPGA using a region +------------------------------------ + +First, allocate the info struct:: + + info = fpga_image_info_alloc(dev); + if (!info) + return -ENOMEM; + +Set flags as needed, i.e.:: + + info->flags |= FPGA_MGR_PARTIAL_RECONFIG; + +Point to your FPGA image, such as:: + + info->sgt = &sgt; + +Add info to region and do the programming:: + + region->info = info; + ret = fpga_region_program_fpga(region); + +:c:func:`fpga_region_program_fpga()` operates on info passed in the +fpga_image_info (region->info). This function will attempt to: + + * lock the region's mutex + * lock the region's FPGA manager + * build a list of FPGA bridges if a method has been specified to do so + * disable the bridges + * program the FPGA + * re-enable the bridges + * release the locks + +Then you will want to enumerate whatever hardware has appeared in the FPGA. + +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 program a FGPA +--------------------- + +.. kernel-doc:: drivers/fpga/fpga-region.c + :functions: fpga_region_program_fpga + +API to add a new FPGA region +---------------------------- + +.. kernel-doc:: include/linux/fpga/fpga-region.h + :functions: fpga_region + +.. kernel-doc:: drivers/fpga/fpga-region.c + :functions: fpga_region_create + +.. kernel-doc:: drivers/fpga/fpga-region.c + :functions: fpga_region_free + +.. kernel-doc:: drivers/fpga/fpga-region.c + :functions: fpga_region_register + +.. kernel-doc:: drivers/fpga/fpga-region.c + :functions: fpga_region_unregister diff --git a/Documentation/driver-api/fpga/index.rst b/Documentation/driver-api/fpga/index.rst index 968bbbfce0e8..c51e5ebd544a 100644 --- a/Documentation/driver-api/fpga/index.rst +++ b/Documentation/driver-api/fpga/index.rst @@ -10,3 +10,4 @@ FPGA Subsystem intro fpga-mgr fpga-bridge + fpga-region diff --git a/Documentation/fpga/fpga-region.txt b/Documentation/fpga/fpga-region.txt deleted file mode 100644 index d38fa3b4154a..000000000000 --- a/Documentation/fpga/fpga-region.txt +++ /dev/null @@ -1,94 +0,0 @@ -FPGA Regions - -Alan Tull 2017 - -CONTENTS - - Introduction - - The FPGA region API - - Usage example - -Introduction -============ - -This document is meant to be an brief overview of the FPGA region API usage. A -more conceptual look at regions can be found in [1]. - -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 [1]. 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 [2] 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 if for partial - reconfiguration. - -=================== -The FPGA region API -=================== - -To register or unregister a region: ------------------------------------ - - int fpga_region_register(struct fpga_region *region); - int fpga_region_unregister(struct fpga_region *region); - -An example of usage can be seen in the probe function of [3] - -To program an FPGA: -------------------- - int fpga_region_program_fpga(struct fpga_region *region); - -This function operates on info passed in the fpga_image_info -(region->info). - -This function will attempt to: - * lock the region's mutex - * lock the region's FPGA manager - * build a list of FPGA bridges if a method has been specified to do so - * disable the bridges - * program the FPGA - * re-enable the bridges - * release the locks - -============= -Usage example -============= - -First, allocate the info struct: - - info = fpga_image_info_alloc(dev); - if (!info) - return -ENOMEM; - -Set flags as needed, i.e. - - info->flags |= FPGA_MGR_PARTIAL_RECONFIG; - -Point to your FPGA image, such as: - - info->sgt = &sgt; - -Add info to region and do the programming: - - region->info = info; - ret = fpga_region_program_fpga(region); - -Then enumerate whatever hardware has appeared in the FPGA. - --- -[1] ../devicetree/bindings/fpga/fpga-region.txt -[2] ./fpga-mgr.txt -[3] ../../drivers/fpga/of-fpga-region.c |