In-kernel API for FPGA Programming
==================================
Overview
--------
The in-kernel API for FPGA programming is a combination of APIs from
FPGA manager, bridge, and regions. The actual function used to
trigger FPGA programming is fpga_region_program_fpga().
fpga_region_program_fpga() uses functionality supplied by
the FPGA manager and bridges. It will:
* lock the region's mutex
* lock the mutex of 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 using info passed in :c:expr:`fpga_region->info`.
* re-enable the bridges
* release the locks
The struct fpga_image_info specifies what FPGA image to program. It is
allocated/freed by fpga_image_info_alloc() and freed with
fpga_image_info_free()
How to program an FPGA using a region
-------------------------------------
When the FPGA region driver probed, it was given a pointer to an FPGA manager
driver so it knows which manager to use. The region also either has a list of
bridges to control during programming or it has a pointer to a function that
will generate that list. Here's some sample code of what to do next::
#include <linux/fpga/fpga-mgr.h>
#include <linux/fpga/fpga-region.h>
struct fpga_image_info *info;
int ret;
/*
* First, alloc the struct with information about the FPGA image to
* program.
*/
info = fpga_image_info_alloc(dev);
if (!info)
return -ENOMEM;
/* Set flags as needed, such as: */
info->flags = FPGA_MGR_PARTIAL_RECONFIG;
/*
* Indicate where the FPGA image is. This is pseudo-code; you're
* going to use one of these three.
*/
if (image is in a scatter gather table) {
info->sgt = [your scatter gather table]
} else if (image is in a buffer) {
info->buf = [your image buffer]
info->count = [image buffer size]
} else if (image is in a firmware file) {
info->firmware_name = devm_kstrdup(dev, firmware_name,
GFP_KERNEL);
}
/* Add info to region and do the programming */
region->info = info;
ret = fpga_region_program_fpga(region);
/* Deallocate the image info if you're done with it */
region->info = NULL;
fpga_image_info_free(info);
if (ret)
return ret;
/* Now enumerate whatever hardware has appeared in the FPGA. */
API for programming an FPGA
---------------------------
* fpga_region_program_fpga() - Program an FPGA
* fpga_image_info() - Specifies what FPGA image to program
* fpga_image_info_alloc() - Allocate an FPGA image info struct
* fpga_image_info_free() - Free an FPGA image info struct
.. kernel-doc:: drivers/fpga/fpga-region.c
:functions: fpga_region_program_fpga
FPGA Manager flags
.. kernel-doc:: include/linux/fpga/fpga-mgr.h
:doc: FPGA Manager flags
.. kernel-doc:: include/linux/fpga/fpga-mgr.h
:functions: fpga_image_info
.. kernel-doc:: drivers/fpga/fpga-mgr.c
:functions: fpga_image_info_alloc
.. kernel-doc:: drivers/fpga/fpga-mgr.c
:functions: fpga_image_info_free
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