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Linux Driver Source for Xilinx FPGA firmware download
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TABLE OF CONTENTS.
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1. SUMMARY
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2. BACKGROUND
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3. DESIGN
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4. HOW TO USE
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5. REFERENCE
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1. SUMMARY
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- Download Xilinx FPGA firmware
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- This module downloads Xilinx FPGA firmware using gpio pins.
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2. BACKGROUND
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An FPGA (Field Programmable Gate Array) is a programmable hardware that is
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used in various applications. Hardware design needs to programmed through
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a dedicated device or CPU assisted way (serial or parallel).
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This driver provides a way to download FPGA firmware.
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3. DESIGN
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- load Xilinx FPGA bitstream format[1] firmware image file using
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kernel firmware framework, request_firmware()
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- program the Xilinx FPGA using SelectMAP (parallel) mode [2]
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- FPGA prgram is done by gpio based bit-banging, as an example
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- platform independent file: gs_fpgaboot.c
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- platform dependent file: io.c
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4. HOW TO USE
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$ insmod gs_fpga.ko file="xlinx_fpga_top_bitstream.bit"
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$ rmmod gs_fpga
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5. USE CASE (from a mailing list discussion with Greg)
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a. As a FPGA development support tool,
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During FPGA firmware development, you need to download a new FPGA
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image frequently.
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You would do that with a dedicated JTAG, which usually a limited
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resource in the lab.
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However, if you use my driver, you don't have to have a dedicated JTAG.
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This is a real gain :)
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b. For the FPGA that runs without config after the download, which
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doesn't talk to any of Linux interfaces (such as PCIE).
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We download FPGA firmware from user triggered or some other way, and that's it.
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Since that FPGA runs on its own, it doesn't require a linux driver
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after the download.
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c. For the FPGA that requires config after the download, which talk to
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any of linux interfaces (such as PCIE)
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Then, this type of FPGA config can be put into device tree and have a
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separate driver (pcie or others), then THAT driver calls my driver to
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download FPGA firmware during the Linux boot, the take over the device
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through the interface.
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6. REFERENCE
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1. Xilinx APP NOTE XAPP583:
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https://www.xilinx.com/support/documentation/application_notes/xapp583-fpga-configuration.pdf
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2. bitstream file info:
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http://home.earthlink.net/~davesullins/software/bitinfo.html
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