Re: [RFC PATCH] fpga: Introduce new fpga subsystem

From: Michal Simek
Date: Wed Sep 25 2013 - 10:51:54 EST

On 09/25/2013 03:55 PM, Yves Vandervennet wrote:
> Greg,
>>> The default hotplug-script doesn't do anything special (that the kernel
>>> couldn't do by itself). What's great is that it could call another
>>> script that adds headers or does whatever other special un-gzipping or
>>> other massaging that the firmware image needs before it gets loaded.
>> Only if you need to do something "special" like this could it justify
>> not using the in-kernel firmware loader. Also note that I think future
>> versions of udev will have the udev firmware loader removed entirely, so
>> watch out for that.
> If the bit stream is in raw format, the kernel can deal with it.
> however, there are "richer" formats for the FPGA bit streams that need
> to be parsed in order to extract the raw data that an FPGA accepts. In
> this case, user space must be involved.

For xilinx there are two fpga formats which are commonly used. BIT and BIN.
BIT format is that richer one but there is no public documentation available
for it. IRC hwicap just support BIT format and because of any unknown decision
zynq can work just with BIN.
But getting BIN from BIT is easy and currently we have the support
in our driver for doing it.

Not sure what options there are for cplds.

But anyway AFAIK richer formats are not problem for us.

The same situation should be for partial bitstreams too.


Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu -
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform

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