Question about "missing" tegra features

Question about "missing" tegra features

[Richard Leitner]

Hello folks,
I've a general question regarding the linux-tegra development:
Why are there tegra features which are available in NVIDIA's kernel tree 
[1], but not included in mainline (or at least your tegra tree)?
I've just noticed that for the USB device controller 
(drivers/usb/gadget/tegra_udc.{c,h}), but it seems there are more such 
"cases".

Is there any documentation on what is supported/included in mainline 
already and what not?

I would be grateful for any response.

Thanks & regards,
richard

[1] http://nv-tegra.nvidia.com/gitweb/?p=linux-3.10.git

Re: Question about "missing" tegra features

[Marc Dietrich]

Hi Richard,

Am Donnerstag, 3. Juli 2014, 09:11:39 schrieben Sie:
> Hello folks,
> I've a general question regarding the linux-tegra development:
> Why are there tegra features which are available in NVIDIA's kernel tree
> [1], but not included in mainline (or at least your tegra tree)?
> I've just noticed that for the USB device controller
> (drivers/usb/gadget/tegra_udc.{c,h}), but it seems there are more such
> "cases".

without being a NV fellow, I guess it's just a lag of developer resources. My 
feeling is that NV releases new SoC versions faster than they can add mainline 
support for it, especially for hw blocks which are seldom used.

On the other hand, you are free to forward port drivers you miss and submit 
them here. But still then someone has to maintain them.

> Is there any documentation on what is supported/included in mainline
> already and what not?

Maybe it's time to add this information to some wiki, e.g. 
http://elinux.org/Tegra

Marc

Re: Question about "missing" tegra features

[Stephen Warren]

On 07/03/2014 01:11 AM, Richard Leitner wrote:
> Hello folks,
> I've a general question regarding the linux-tegra development:
> Why are there tegra features which are available in NVIDIA's kernel tree
> [1], but not included in mainline (or at least your tegra tree)?
> I've just noticed that for the USB device controller
> (drivers/usb/gadget/tegra_udc.{c,h}), but it seems there are more such
> "cases".

Just like I think Marc already responded, It's simply a matter of
resources; the upstreaming team isn't as large as the product team.

> Is there any documentation on what is supported/included in mainline
> already and what not?

I don't believe so, no.

The main features I can think of are:

* Various power/performance optimizations.
* Various IO controllers on newer chips (such as SATA, Tegra124 PCIe,
USB3), although there are patches sent for all of these now. NOR flash,
I2C/SPI slave mode, one-wire, perhaps a few other minor IO controllers.
* Various features in supported IO controllers (e.g. high-speed eMMC/SD
modes, USB2 bus suspend, ...)
* USB device mode.