[U-Boot] phy ic isn't reset

[Andreas Bießmann]

Dear Bo Shen,

On 04/18/2013 08:32 AM, Bo Shen wrote:
> Hi Alex
> 
> On 4/18/2013 13:27, alex wrote:
>>
>> At 2013-04-18 09:23:48,"Bo Shen" <voice.shen at atmel.com> wrote:
>>> Hi Alex,
>>>
>>> On 4/17/2013 18:29, alex wrote:
>>>> Hi:
>>>>    I work on one board based on at9g25evk board now. I find one issue
>>>> that phy IC isn't reset, so network can't work. Only the different
>>>> crystal with evk board is connected to PHY IC. I copy the phy-reset
>>>> part
>>>> of at9260 to at9g25. It can work now. Please the maintainer of at9gx5
>>>> check this. The modification I do is as below:
>>>
>>> As you mentioned, you use different crystal, please specify this in
>>> detail.
>>
>> S3225A package, 50Mhz crystal oscillator. ocean comonents ltd. --->
>> can work.
>>
>> asem series:ASEM1-50.000MHZ-LC-T  ---->can't work.
>>
>>>
>>>> +
>>>> +#ifdef CONFIG_MACB
>>>> +int at91sam9x5ek_macb_hw_init(void)
>>>> +{
>>>> +        struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
>>>> +        struct at91_port *pioa = (struct at91_port *)ATMEL_BASE_PIOA;
>>>> +       struct at91_rstc *rstc = (struct at91_rstc *)ATMEL_BASE_RSTC;
>>>> +       unsigned long erstl;
>>>> +
>>>> +        /* Enable EMAC clock */
>>>> +        writel(1 << ATMEL_ID_EMAC0, &pmc->pcer);
>>>> +
>>>> +       erstl = readl(&rstc->mr) & AT91_RSTC_MR_ERSTL_MASK;
>>>> +
>>>> +       /* Need to reset PHY -> 500ms reset */
>>>> +       writel(AT91_RSTC_KEY | AT91_RSTC_MR_ERSTL(13) |
>>>> +                       AT91_RSTC_MR_URSTEN, &rstc->mr);
>>>> +
>>>> +       writel(AT91_RSTC_KEY | AT91_RSTC_CR_EXTRST, &rstc->cr);
>>>> +
>>>> +       /* Wait for end hardware reset */
>>>> +       while (!(readl(&rstc->sr) & AT91_RSTC_SR_NRSTL))
>>>> +               ;
>>>> +
>>>> +       /* Restore NRST value */
>>>> +       writel(AT91_RSTC_KEY | erstl | AT91_RSTC_MR_URSTEN,
>>>> +                       &rstc->mr);
>>>> +
>>>> +       at91_macb_hw_init();
>>>> +}
>>>> +#endif
>>>
>>> On at91sam9g25ek, it don't need this patch. The network work properly.
>>>
>>> Btw, please help provide the log information for why not ethernet
>>> doesn't work.
>>
>>  From at91sam9g25ek side, no any error. If you only plug network line
>> , the network traffic led is always off, that is,DM9161AEP doesn't
>> check this change.
>> Even if I add this patch, no any defect, right?
> 
> I won't suggest do like this, if you use reset controller, it will
> assert nRST pin. If one more device use nRST, it will also reset other
> device. if only PHY use nRST and no other consideration, I think it is OK.

I would like to point out that older atmel eval kits use this trick
heavily. This is due to missing pullup/pulldown on the board, therefore
it is required to setup some gpio first and then issue a reset (again)
to the PHY cause it is misconfigured. Maybe this can also be esablished
with some (R)MII communication, but thats how it is implemented currently.

Regarding the crystal, what is the root cause of your issue? Does it not
oscillate or is your PHY 'mis-configured' in means of wrong initial
setup on configuration lines?
In both cases I recommend to find a HW solution for the final product.

Best regards

Andreas Bießmann