[PATCH v2] ahs2: initial support

[Holger Schurig]

> This file is currently not compiled in.

I know, because I current environment have my own _defconfig still as
a quilt-patch. It's local, because it contains hardcoded the IP
address of my development box for TFTP, for example. I thought that I
put up the real environment once I'm able to decide about the final
environment.

> You can either remove it in case
> you don't need it, or move the env/ directory in your board file to
> defaultenv-ahs2/, add to the make rules:
>
> bbenv-y += defaultenv-ahs2
>
> And in some initcall do:
>
> defaultenv_append_directory(defaultenv_ahs2);
>
> This way the ahs2 specific files will be in the environment exactly when
> the binary is started on your board.

Good to know. But, as said, currently I cannot do this. After all,
this is an "initial support" patch.


>> +static inline void early_uart1_init(void)
>> +{
>> +     // 2681: IOMUXC_UART1_UART_RX_DATA_SELECT_INPUT to ALT1 (CSI0_DATA10_ALT3 )
>> +     // 2621: IOMUXC_ECSPI2_MISO_SELECT_INPUT to ALT2 (CSI0_DATA10_ALT2)
>> +     // 2092: IOMUXC_SW_MUX_CTL_PAD_CSI0_DATA10 to ALT3 (UART1_TX_DATA)
>
> What are these numbers?

The page numbers in the i.MX6 reference manual :-)



> Please replace with /* C comments */

Sigh, we still aren't in the year 2014 ?!?!?   Somehow this  "no //"
reminds me that the other day a collegue of me asked me to set the
baudrate to 38400 :-)

And while at it: may I suggest that barebox switches to C99?   Thould
would also liberate the placement of variable definitions ...



>> +     aliases {
>> +             ethernet0 = &fec;
>> +     };
>
> Could you add this to the imx6qdl.dtsi file instead?

Sure, I actually don't even know if it is needed. I took it via cut-and-paste.

> Normally this should be in the upstream dtsi file, but as long as it
> isn't we can keep it in barebox.

I'll look if it is needed, and if yes, I'll put it in the dtsi file.


>> +     phy: ethernet-phy at 0 {
>> +             speed = <10>;
>> +             duplex = <1>;
>> +     };
>
> speed 10? really?

Now, there are two reasons why I tried this:

* our hardware guys had an error on our layout (wrong resistors). I
should have removed that, my board is now fixed.

* currently, the most time consuming operation in in my
barebox-loads-linux-via-TFTP is the autonegotiation of the PHY. After
"ifup eth0" a "time ping 10.1.2.3" reports 4580ms. Transfers after
that are fast enought. My attempt was a try to use some fixes speed,
even a slow one.

But I now grepped for "of_" below drivers/net, I actually think that
neiher fec_imx.c nor phy/smsc.c cares for device tree settings.

Do you have any idea on how to speed up auto-negotiation?