Linux 2.6.28 Porting to Oxnas

[ftcodes]

Exactly, the SGDMA is used in the SATA and for the DMA access to the Ethernet part. So, they share a function block within the SoC (PLX-NAS7820). That needs a sharing layer and for that, we have to get into both SATA and Ethernet driver code. I would probably go for a preallocated principle but yet the DMA core needs to be understood enough for that.

Following modules are from Synopsis AFAIK:
- 10/100/1G Ethernet (GMAC)
- SATA core (at least partially)
- DMA core (SGDMA)

I checked http://www.synopsys.com. For a corporate mail at least, they seem to give datasheet access. So, we could get probably datasheets for those cores from there.

And there is Pull Request on github.com, so it is simple to get stuff shared.

[WarheadsSE]

The SATA core is actually based on the OX934

[ftcodes]

But still when checking u-boot source I found a lot of references to synopsys at least for the PHY.

I suggest we should coordinate efforts to some extent. For example, I could go for the analysis stuff like SGDMA.

At least, we are not re-doing a lot of work per person.

[WarheadsSE]

Yes, the PHY attached through the lines is indeed a synopsis. Check my u-boot sources, and you will see the exact device id. Heck, it ought to be in the kernel code. I don't have the documents in front of me at the moment, or I'd spit out what I can (limited as that is)

[ftcodes]

I know that those documents cannot be easily shared due to the NDA. However, what type of documents is within the hardware reference manual set?

I hope we get it a bit more coordinated since a single person is easy but with multiple persons we should avoid redoing too much work.

And since there is a lot from Synopsys, it would not come unexpected when the OX934 would actually be Synopsys based entirely.

[WarheadsSE]

I have access to everything referenced on this page: http://www.plxtech.com/products/consumer/nas7820

Included in this information is about as in depth as you might like, including reference platform pinouts and interconnect diagrams.

[ftcodes]

That is what I thought already but I was more interested in whether that Hardware reference manual are containing things like detailed register set descriptions and some flow diagrams.

[WarheadsSE]

I'll review when I arrive home, but yes, in some instances.

[ftcodes]

At least the blocks about SGDMA, SATA and Ethernet would be nice when they are complete enough for understanding.

However, with some registers, I recognized recurring design methods like on the GPIO cores. That is why I added full GPIO support as it is thought up by kernel developers. So, the LED trigger gpio button is actually working.

Maybe you have tried that GPIO button support already.

[WarheadsSE]

Here's the best I can do, without unwittingly violating too much:
http://ppl.ug/Kpo5YWYbqFw/

The NAS 7820 has a single SATA controller with inbuilt SGDMA and cipher core. "SGDMA engine to DMA directly between the SATA contoller and DDR"

The 7820 containt a single GbE MAC (GMAC) AHB master interface with DMA (bulk transfer), built-in SGDMA engine, RGMII interfacing (listed NOT GMII or MII!), with support of up to 8K JF w/ tx cksum.