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