From: Alan Tull <delicious.quinoa@gmail.com>
To: Moritz Fischer <moritz.fischer@ettus.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
"Nadathur, Sundar" <sundar.nadathur@intel.com>,
Yves Vandervennet <yves.vandervennet@linux.intel.com>,
"matthew.gerlach@linux.intel.com"
<matthew.gerlach@linux.intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
"linux-fpga@vger.kernel.org" <linux-fpga@vger.kernel.org>,
"Marek Va??ut" <marex@denx.de>
Subject: Re: [RFC 7/8] fpga-region: add sysfs interface
Date: Wed, 22 Feb 2017 10:52:12 -0600 [thread overview]
Message-ID: <CANk1AXQVVsUf4QpA=Bt7Hsuxy+8M9bEYk90xX9Ux+U4vaQiKeg@mail.gmail.com> (raw)
In-Reply-To: <CAAtXAHfnYd0iWVK6HaAzgvwV5PN5jYYSXnxEAqDoYMiPKeR8nQ@mail.gmail.com>
On Wed, Feb 22, 2017 at 10:44 AM, Moritz Fischer
<moritz.fischer@ettus.com> wrote:
> On Wed, Feb 22, 2017 at 8:33 AM, Alan Tull <delicious.quinoa@gmail.com> wrote:
>> On Tue, Feb 21, 2017 at 11:38 PM, Moritz Fischer
>> <moritz.fischer@ettus.com> wrote:
>>
>> Hi Moritz,
>>
>>> Hi all,
>>>
>>> On Tue, Feb 21, 2017 at 9:12 PM, Jason Gunthorpe
>>> <jgunthorpe@obsidianresearch.com> wrote:
>>>> On Tue, Feb 21, 2017 at 07:49:19PM -0800, Moritz Fischer wrote:
>>>>
>>>>> fdt does this out of the box, too. So far I've seen nothing fdt
>>>>> couldn't do (or doesn't do let's rather say).
>>>>
>>>> tlv/fdt/http headers are all essentially exactly the same
>>>> thing. Key/value pairs with various encoding schemes.
>>>>
>>>> I don't think we don't need a tree of data, so fdt is overkill.
>>>>
>>>> tlv is not substantially easier to parse correctly than the
>>>> structured plain text headers.. It is just in binary so it can
>>>> represent binary-ish things better.
>>>
>>> TLV Seems easy enough. To give an update, I played with fdt a bit to see
>>> how far I get in half an hour. I got bool / int / strings to work
>>> quite fast (~30mins).
>>
>> Thanks for doing this fast piece of exploratory coding. It does
>> confirm that for Linux, using fdt is pretty straightforward here.
>> However...
>>
>>> Please disregard the horrible hackyness of this ...
>>>
>>> For simplicity I stuck the header on top of my bitfile with:
>>>
>>> <snip>
>>> /dts-v1/;
>>>
>>> /{
>>> description = "Test";
>>> compressed = <0>;
>>> encrypted = <1>;
>>> };
>>
>> I understand that this is a simplified example, but it looks a lot
>> like KVP which then gets compiled by dtc.
>>
>> If we do KVP or TLV we get skip using dtc, which would be nice for non-dt
>> OS's using the same images.
>
> I used dtc for pure lazyness. Writing a blob to a file using libfdt is
> about as much
> code as parsing it.
Thanks for that clarification. I haven't used libfdt myself. That
takes care of the license issue I brought up below.
I have heard that MS is averse to using DT, but I'm not clear
about why other than that it isn't native to Windows already.
Alan
> Even with KVP or TLV you have some code that needs
> to encode / pack your header into a file.
>
> libfdt has an example that creates an empty tree. Write that to a file, done.
>
> 1: Create empty tree
> https://github.com/dgibson/dtc/blob/master/libfdt/fdt_empty_tree.c
>
> 2: fopen / fwrite, done
>
>> Also, the license of libfdt allows the use by proprietary
>> os's, but that's not true for dtc.
>
> Why would that be an issue, you don't need to link anything to run
> dtc. That being
> said as I pointed out above you don not have to actually use dtc if the values
> are known ahead of time (like in our case). What you'd get from using dtc is to
> encode arbitrary values (for the types supported).
>
> Cheers,
>
> Moritz
next prev parent reply other threads:[~2017-02-22 16:59 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-15 16:14 FPGA Region enhancements and fixes Alan Tull
2017-02-15 16:14 ` [RFC 1/8] fpga-mgr: add a single function for fpga loading methods Alan Tull
2017-02-16 0:36 ` matthew.gerlach
2017-02-15 16:14 ` [RFC 2/8] fpga-region: support more than one overlay per FPGA region Alan Tull
2017-02-16 16:50 ` matthew.gerlach
2017-02-16 17:35 ` Alan Tull
2017-02-15 16:14 ` [RFC 3/8] fpga-bridge: add non-dt support Alan Tull
2017-02-15 16:14 ` [RFC 4/8] doc: fpga-mgr: separate getting/locking FPGA manager Alan Tull
2017-02-17 17:14 ` Li, Yi
2017-02-17 21:55 ` Alan Tull
2017-02-17 17:52 ` Moritz Fischer
2017-02-17 22:02 ` Alan Tull
2017-02-15 16:14 ` [RFC 5/8] " Alan Tull
2017-02-15 16:14 ` [RFC 6/8] fpga-region: separate out common code to allow non-dt support Alan Tull
2017-02-15 16:14 ` [RFC 7/8] fpga-region: add sysfs interface Alan Tull
2017-02-15 17:21 ` Jason Gunthorpe
2017-02-15 17:46 ` Alan Tull
2017-02-15 17:55 ` Moritz Fischer
2017-02-15 18:06 ` Jason Gunthorpe
2017-02-15 18:23 ` Alan Tull
2017-02-15 18:31 ` Moritz Fischer
2017-02-15 19:49 ` Jason Gunthorpe
2017-02-15 22:49 ` Alan Tull
2017-02-15 23:07 ` Jason Gunthorpe
2017-02-15 20:07 ` matthew.gerlach
2017-02-15 20:37 ` Jason Gunthorpe
2017-02-15 20:54 ` Moritz Fischer
2017-02-15 21:15 ` Jason Gunthorpe
2017-02-15 21:36 ` Moritz Fischer
2017-02-15 22:42 ` Alan Tull
2017-02-16 0:16 ` Moritz Fischer
2017-02-16 17:47 ` Alan Tull
2017-02-16 17:56 ` Jason Gunthorpe
2017-02-16 18:11 ` Moritz Fischer
2017-02-17 22:28 ` Yves Vandervennet
2017-02-18 2:30 ` Moritz Fischer
2017-02-18 12:45 ` Nadathur, Sundar
2017-02-18 20:10 ` Alan Tull
2017-02-18 20:45 ` Moritz Fischer
2017-02-19 15:00 ` Alan Tull
2017-02-19 23:16 ` Alan Tull
2017-02-20 23:49 ` Moritz Fischer
2017-02-21 18:33 ` Alan Tull
2017-02-22 3:13 ` Nadathur, Sundar
2017-02-22 3:49 ` Moritz Fischer
2017-02-22 5:12 ` Jason Gunthorpe
2017-02-22 5:38 ` Moritz Fischer
2017-02-22 5:46 ` Nadathur, Sundar
2017-02-22 6:05 ` Moritz Fischer
2017-02-22 16:44 ` Jason Gunthorpe
2017-02-22 17:50 ` Moritz Fischer
2017-02-22 17:54 ` Jason Gunthorpe
2017-02-22 17:57 ` Moritz Fischer
2017-02-22 16:33 ` Alan Tull
2017-02-22 16:44 ` Moritz Fischer
2017-02-22 16:52 ` Alan Tull [this message]
2017-02-27 20:09 ` Alan Tull
2017-02-27 22:49 ` Moritz Fischer
2017-02-28 0:04 ` matthew.gerlach
2017-02-15 21:20 ` Anatolij Gustschin
2017-02-15 16:14 ` [RFC 8/8] doc: fpga: add sysfs document for fpga region Alan Tull
2017-02-28 17:35 ` FPGA Region enhancements and fixes Alan Tull
2017-02-28 22:03 ` Alan Tull
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