Re: TW2866 i2c driver and solo6x10

[Marty Plummer <netz.kernel@gmail.com>]

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On 08/03/2016 02:28 PM, Andrey Utkin wrote:
> On Wed, Jul 27, 2016 at 11:51:22PM -0500, Marty Plummer wrote:
>> I have one of those rebranded chinese security dvrs, the ones with all the gaping
>> security holes. I'd like to fix that up and setup a good rtsp server on it, but
>> first comes low-level stuff, drivers and such. I've been squinting at the pcb and
>> ID'ing chips for a bit now, and I've figured most of them out. Looks like the actual
>> video processing is done on 4 tw2866 chips, though the kernel module has symbols
>> referring to tw2865. I've seen another driver in the kernel tree, the bluecherry
>> solo6x10, but that's on the pci bus. as far as I can figure, the dvr uses i2c for
>> them. So, what I'm wondering is would it be feasible to factor out some of the solo
>> functionality into a generic tw2865 driver and be able to pull from that for an i2c
>> kernel module? I'd really hate to have to rewrite the whole thing, duplicated code
>> and overworking are generally a bad idea, even if I do have a datasheet for the chip
>> in question
> 
> 
> Hi Matt,
> 
> Bluecherry LLC software developer here (barely knowing about tw28xx stuff).
> 
> If I was you, I'd restrain from such project unless I had a bulk of such
> hardware, not just single unit. This is because things are hard to get
> right without tinkering step by step. Also somebody would still need to
> do fair amount of coding. And unless you are already qualified to do it
> alone, you'd need many cycles of asking questions and providing lots of
> details of your actual system. If you are interested in merging your
> results upstream, then there's even more efforts to put.
> As a developer affiliated with Bluecherry LLC, I will do my best to help
> you, but I am mere mortal with all sorts of constraints - knowledge,
> time, etc. But I or Bluecherry won't just make everything for you, even
> if you send us a sample of hardware (which would be a good start for a
> volunteer willing to take that challenge).
> So feel free to post here your specific questions if you go for it.
> 
An understanable sentement, but its not just about me (though I actually own two
of the same dvr's). There is a large number, if reports are to be believed, of
more or less identical dvr systems with the same security holes and hard-coded
credentials, with no vendor firmware updates. In addition, I am also in possesion
of the chip vendor sdk with full source code for the kernel and modules and a
host of pertenant datasheets. My end goal is something along the line of openwrt
or lede for these systems in the interest of the community at large.

I'm not averse to the concept of hard work, and while I'm very experienced when
it comes to kernel hacking I think I can manage well enough with relevant source
and examples, of which there is a large amount.

One concern I have is dealing with devicetree, but I think I can manage.


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